Amareshwar Singh - Academia.edu (original) (raw)

Papers by Amareshwar Singh

Circulation, 2006

The tyrosine kinase receptor erbB2 (or Her2 in humans) is a member of the epidermal growth factor... more The tyrosine kinase receptor erbB2 (or Her2 in humans) is a member of the epidermal growth factor receptor. It is highly expressed in many cancer types, and its overexpression is correlated with a ...

Blood, 2008

Background: Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma (NHL) with a prevalence o... more Background: Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma (NHL) with a prevalence of approximately 15,000 cases in the United States. Although current therapeutics extend longevity, the median survival is 3 to 5 years warranting continued investigation for newer therapeutics. MCL is characterized by cells with enhanced proliferation combined with impaired apoptosis characteristic of indolent lymphomas. Therefore, therapeutic approaches targeting transcription, translation, or cellular bioenergetics may prove to be more effective than therapies targeting DNA replication. In addition, therapeutic strategies that exploit the altered cellular metabolism of tumor cells may be beneficial. Nucleoside analogues have been used extensively in the treatment of hematologic malignancies and are selective for tumor cells. Our laboratories have developed two purine nucleoside analogues i.e. 8-chloro-adenosine (currently in clinical trials) and a congener, 8-amino-adenosine (8-NH2-Ado...

Blood, 2007

MCL, characterized by the t(11;14), results in the overexpression of cyclin D1, and typically has... more MCL, characterized by the t(11;14), results in the overexpression of cyclin D1, and typically has an aggressive clinical course. The disease is not curable by conventional therapy, and new modalities are needed. A MCL cell line, Granta, has been studied and has a complex karyotype and genetic alterations of cell cycle regulatory genes. ATRA is a metabolic derivative of retinoic acid (RA). Upon binding with ATRA, its receptors become transcriptionally activated and transactivate their target genes leading to cell growth arrest or apoptosis. We hypothesized that ATRA would lead to apoptosis or cell growth arrest in Granta MCL cells. We used ATRA nanodisks for increased solubilization and in vivo delivery. Reactive oxygen species (ROS) were measured with fluorescence-activated cell sorting (FACS) following incubation at 6 hours (h) and 24 h with ATRA (12.5–50nM). At 6 h, ATRA induced dose-dependent generation of ROS, which returned to baseline at 24 h. The levels of ROS in untreated co...

Blood, 2007

The cytotoxic activity of As2O3 in leukemia and myeloma has been shown to be mediated in part by ... more The cytotoxic activity of As2O3 in leukemia and myeloma has been shown to be mediated in part by ROS. We determined the mechanism of cytotoxicity of As2O3 in HL and NHL cell lines. Ramos, HF-1, SUDHL4 (NHL lines), and L428 (HL line) cells were cultured with increasing clinically relevant As2O3 concentrations (1.0mm-10mm) at 24-72 hours with and without the oxidizing agent, buthionine sulfoxime (BSO, 100mm), and with and without caspase inhibitors Z-VAD-FMK and Z-IETD-FMK. Apoptosis was measured by Annexin-V/propidium iodide (PI) staining and detected by flow cytometry (FACS). ROS was measured by oxidation of 2′7′ dichlorofluorescein diacetate (H2DCFDA) to Dichlorofluorescein (DCF) and analyzed by FACS. Immunoblots were performed for bcl-2, PARP, cleaved caspases 3, 8, 9, and mitogen activated protein kinase (MAPK) pathways (ERK, JNK, and p38 activation). As2O3 alone at 10mM resulted in dose- and time-dependent apoptosis in all cell lines (HL and NHL) with >75% annexin+/PI+ betwee...

Blood, 2007

We have reported that MGd, an expanded porphyrin and redox stress inducer, lowers p53 protein but... more We have reported that MGd, an expanded porphyrin and redox stress inducer, lowers p53 protein but not message in lymphoma cell lines. These results suggested that there is post-translational modification of p53 induced by MGd, and that this effect depends on the presence of ascorbate (Asc) or zinc (Zn). To expand these earlier studies, we measured the expression of oxidant and antioxidant genes in Ramos (Burkitt’s) cells. We incubated Ramos cells for 5 hours with MGd 100μM with or without Zn acetate (Zn, 100μM), Asc 100μM, and Nutlin-3 15μM. Following incubation, total RNA was isolated by the Qiagen method and dissolved in RNase-free water. 1.0 μg RNA was used for reverse transcription using the Taq DNA polymerase system. PCR amplification was performed at 94°C for 30 sec (denaturation), 55°C (annealing) and 72°C (extension) for 35 cycles. This was followed by an extension at 72°C for 10 minutes. Anti-sense primers and sense primers for SESN1(T2), SESN2, GPX1, CDKN1A, and PP1A were ...

Blood, 2010

3934 Background: Mantle cell lymphoma (MCL) is a pre–germinal center neoplasm characterized by cy... more 3934 Background: Mantle cell lymphoma (MCL) is a pre–germinal center neoplasm characterized by cyclin D1 overexpression resulting from translocation of the cyclin D1 gene on 11q13 to the promoter of the immunoglobulin heavy chain locus on 14q32. Since MCL is incurable with standard lymphoma therapies, new treatment approaches are needed that target specific biologic pathways. The bioactive polyphenol curcumin (Curc), derived from the rhizome of Curcuma longa Linn, has been shown to have pleiotropic activities related to its complex chemistry and its influence on multiple signaling pathways including NF-kB, Akt, Nrf2 and pathways involved in metastasis and angiogenesis. Curc has been shown to cause growth arrest and apoptosis of BKS-2 immature B-cell lymphoma by downregulating growth and survival promoting genes (Clin Immunol 1999; 93:152). However, because of poor aqueous solubility Curc has had limited clinical utility, so investigators have explored nanoparticle drug delivery appr...

Blood, 2009

2713 Poster Board II-689 Introduction: HIF-1 is a transcription factor that serves as a master re... more 2713 Poster Board II-689 Introduction: HIF-1 is a transcription factor that serves as a master regulator of cellular responses to hypoxia and regulates genes required for adaptation to hypoxia. Although the expression of HIF-1α subunit is constitutive, HIF-1α protein levels are regulated in response to oxygen tension. Under normoxic conditions, HIF-1α is degraded by the proteasome, and HIF-1 remains inactive. In hypoxia, HIF-1α is stabilized and forms a complex with HIF-1β that allows HIF-1 to function as a transcription factor. Thus, HIF-1α is activated only during hypoxia under normal physiologic conditions. By contrast, HIF-1α is frequently activated in cancer cells, including under normoxic conditions by oncogene products or impaired activity of tumor suppressor genes. We previously reported that there is constitutive stabilization of HIF-1α in many non-Hodgkin lymphoma (NHL) cell lines as well as among a significant fraction of diffuse large B-cell lymphoma (DLBCL) and follicul...

Blood, 2006

Disruption of the tumor suppressor p53 is a frequent event in malignant disorders, including lymp... more Disruption of the tumor suppressor p53 is a frequent event in malignant disorders, including lymphomas. Loss of constitutive low-level p53-dependent expression of anti-oxidant proteins could render cells more susceptable to the acute oxidant stress induced by oxidant generating agents such as MGd, bortezomib and rituximab. Alternatively, loss of p53 would render cells more resistant to apoptosis normally seen after strong activation of p53 activity in response to DNA damage. We hypothesized that the ROS generating expanded porphyrin, MGd, which we have previously shown to cause apoptosis in lymphoma and myeloma cells, results in loss of low-level, basal p53 expression, making cells more susceptable to oxidant stress. In order to test this hypothesis, we incubated Ramos, HIF-1 and SUDHL-4 lymphoma cells for 30, 60, 120 and 300 min with MGd (0.1–100 μM) with or without zinc acetate (Zn) and ascorbate. Following incubation, whole cell lysates were collected, electrophoresed on SDS-PAGE...

Blood, 2012

157 We report a nanoparticle-enabled therapeutic approach to B cell lymphoma using synthetic, hig... more 157 We report a nanoparticle-enabled therapeutic approach to B cell lymphoma using synthetic, high-density lipoprotein nanoparticles (HDL-NP). Like natural HDLs, biomimetic HDL-NPs target scavenger receptor type B-1 (SR-B1), a high-affinity HDL receptor expressed by lymphoma cells. Functionally, and unlike natural HDL, a gold nanoparticle template used to control HDL-NP synthesis enables differential manipulation of cellular cholesterol flux through SR-B1. Recent evidence in lymphoblasts and myeloblasts from patients with acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) demonstrates enhanced uptake of cholesterol through high-density lipoprotein (HDL) carriers, which may result in increased cell proliferation. We therefore hypothesized that by targeting SR-B1, we could manipulate cholesterol flux in lymphoma cells thereby targeting cellular signaling pathways that would lead to cell death and offer an innovative approach to the treatment of lymphoma and other cancer...

Blood, 2009

1698 Poster Board I-724 Background HIF-1á is a transcription factor that regulates gene expressi... more 1698 Poster Board I-724 Background HIF-1á is a transcription factor that regulates gene expression in response to decreases in cellular oxygenation (hypoxia). Genes activated by HIF are involved in glycolysis, glucose transport, angiogenesis, cell proliferation, cell migration, cell metabolism, and cell survival. Many of these genes confer protection against the consequences of oxygen deprivation while others enhance resistance to chemotherapy or radiotherapy. Clinically, evidence of elevated HIF-1á protein correlates with poor prognosis in lung, breast, colorectal, brain, pancreatic, ovarian, renal and bladder cancers. Our prior data found that constitutive expression of HIF-1á is enhanced in a set of established lymphoma cell lines (Evens et al, BJH, 2008), underscoring the potential impact of HIF in lymphoma. We also found that HIF-1á was stabilized in lymphoma specimens from patients with follicular lymphoma and DLBCL. These observations highlight a potential importance of H...

Anticancer research, Nov 1, 2017

The emerging field of nanotechnology meets the demands for innovative approaches in the diagnosis... more The emerging field of nanotechnology meets the demands for innovative approaches in the diagnosis and treatment of cancer. The nanoparticles are biocompatible and biodegradable and are made of a core, a particle that acts as a carrier, and one or more functional groups on the core which target specific sites. Nanotech in drug delivery includes nanodisks, High Density Lipoprotein nanostructures, liposomes, and gold nanoparticles. The fundamental advantages of nanoparticles are: improved delivery of water-insoluble drugs, targeted delivery, co-delivery of two or more drugs for combination therapy, and visualization of the drug delivery site by combining imaging system and a therapeutic drug. One of the potential applications of nanotechnology is in the treatment of cancer. Conventional methods for cancer treatments have included chemotherapy, surgery, or radiation. Early recognition and treatment of cancer with these approaches is still challenging. Innovative technologies are needed ...

International Journal of Molecular Sciences, 2018

Apoptosis, the cell’s natural mechanism for death, is a promising target for anticancer therapy. ... more Apoptosis, the cell’s natural mechanism for death, is a promising target for anticancer therapy. Both the intrinsic and extrinsic pathways use caspases to carry out apoptosis through the cleavage of hundreds of proteins. In cancer, the apoptotic pathway is typically inhibited through a wide variety of means including overexpression of antiapoptotic proteins and under-expression of proapoptotic proteins. Many of these changes cause intrinsic resistance to the most common anticancer therapy, chemotherapy. Promising new anticancer therapies are plant-derived compounds that exhibit anticancer activity through activating the apoptotic pathway.

Acta cardiologica, 1992

Serum ceruloplasmin levels were estimated in 81 patients within one week after an attack of acute... more Serum ceruloplasmin levels were estimated in 81 patients within one week after an attack of acute myocardial infarction. A total of 126 healthy subjects were taken as controls and investigated for this copper containing protein. Results showed that there is an elevation in the levels of serum ceruloplasmin in patients as compared to the controls. Ceruloplasmin levels showed a return to almost normal values in 54 follow-up cases of acute myocardial infarction during the fourth week after infarction.

Studies were performed to determine the effects of PTH and related compounds on phosphatidylcholi... more Studies were performed to determine the effects of PTH and related compounds on phosphatidylcholine (PC) hydrolysis in UMR-106 cells and the pathway by which the PTH effects occurred. The responses were compared with those of phorbol 12,13-dibutyrate (PDBu). Both bovine PTH-(1-34) (bPTH-(1-34)) and PDBu stimulated PC hydro- lysis within 10 min. Significant effects were elicited by concentrations of 0.3-1 nM bPTH-(1-34) and 5 nM PDBu. Dose-dependent increases were seen at higher concentrations of both compounds, however, the response to bPTH-(1-34) was reduced at 30 nM. Bovine or human PTH-(1-34) and human PTH-related peptide-(1-34) (hPTHrP-(1-34)) were equipotent in their effects, whereas bovine (Nle8,18Tyr34)PTH- (3-34) amide (bPTH-(3-34)) and hPTH-(1-31) amide (hPTH-(1-31)) were less potent than bPTH-(1-34). bPTH-(3-34) did not antagonize the effects of bPTH-(1-34). Down-regulation of protein kinase C isozymes by 24-h treatment with PDBu completely prevented the stimulatory effect...

Nanomedicine: Nanotechnology, Biology and Medicine, 2011

Nanodisks (ND) are nanoscale, disk-shaped phospholipid bilayers whose edge is stabilized by apoli... more Nanodisks (ND) are nanoscale, disk-shaped phospholipid bilayers whose edge is stabilized by apolipoproteins. In the present study, ND were formulated with the bioactive polyphenol, curcumin, at a 6:1 phospholipid:curcumin molar ratio. Atomic force microscopy revealed that curcumin-ND are particles with diameters <50 nm and thickness of a phospholipid bilayer. When formulated in ND, curcumin is water-soluble and gives rise to a characteristic absorbance spectrum with a peak centered at 420 nm. Fluorescence spectroscopy of curcumin-ND provided evidence of self-quenching. Incubation of curcumin-ND with empty-ND relieved the selfquenching, indicating redistribution of curcumin between curcumin loaded-and empty-ND. In HepG2 cells, curcumin-ND mediated enhanced cell growth inhibition compared to free curcumin. In a cell culture model of mantle cell lymphoma, curcumin-ND were a more potent inducer of apoptosis than free curcumin. The nanoscale size of the complexes, combined with their ability to solubilize curcumin, indicates ND may have in vivo therapeutic applications.

Leukemia & Lymphoma, 2011

Cellular Signalling, 2004

Parathyroid hormone (PTH) stimulates both bone formation and resorption by activating diverse ost... more Parathyroid hormone (PTH) stimulates both bone formation and resorption by activating diverse osteoblast signalling pathways. Upstream signalling for PTH stimulation of protein kinase C-a (PKCa) membrane translocation and subsequent expression of the proresorptive cytokine interleukin-6 (IL-6) was investigated in UMR-106 osteoblastic cells. PTH 1-34, PTH 3-34, PTHrP and PTH 1-31 stimulated PKCa translocation and IL-6 promoter activity. Pharmacologic intervention at the adenylyl cyclase (AC) pathway (forskolin, IBMX, PKI) failed to alter PTH 1-34-or PTH 3-34-stimulated PKCa translocation. The phosphoinositol-phospholipase C (PI-PLC) antagonist U73122 slightly decreased PTH 1-34-stimulated PKCa translocation; however, the control analogue U73343 acted similarly. Propranolol, an inhibitor of phosphatidic acid (PA) phosphohydrolase, decreased diacylglycerol (DAG) formation and attenuated PTH 1-34and PTH 3-34-stimulated PKCa translocation and IL-6 promoter activity, suggesting a phospholipase D (PLD)-dependent mechanism. This is the first demonstration that PLD-mediated signalling leads to both PKC-a translocation and IL-6 promoter activation in osteoblastic cells.

Arteriosclerosis, Thrombosis, and Vascular Biology, 1996

Genetic and dietary effects on LDL phenotypes, including predominant LDL particle diameter, LDL s... more Genetic and dietary effects on LDL phenotypes, including predominant LDL particle diameter, LDL size distribution, and non–HDL cholesterol and apoB concentrations, were investigated in 150 pedigreed baboons that are members of 19 sire groups. Baboons were fed a sequence of three defined diets differing in levels of fat and cholesterol. Increasing dietary fat had relatively little effect on two measures of LDL particle size. However, increasing the level of cholesterol in the diet resulted in larger increases of the predominant LDL particle diameters and in the proportion of stain on LDLs >28 nm. As expected, apoB and non–HDL cholesterol concentrations significantly increased when levels of dietary fat and cholesterol were increased. Correlations among the LDL phenotypes suggested that several different aspects of the LDL phenotype were captured by the four LDL measures across the three diets. Genetic effects indicated by sire group membership were significant both for expression ...

Analytical Biochemistry, 1992

A novel method to assay insect plasma lipid transfer particle (LTP) activity has been developed t... more A novel method to assay insect plasma lipid transfer particle (LTP) activity has been developed that employs insect high density lipophorin (HDLp) and human low density lipoprotein (LDL) as donor/acceptor substrate particles. At a 3:1 or greater HDLp:LDL protein ratio, LTP-mediated net vectorial transfer of diacylglycerol from lipophorin to LDL produces destabilized LDL particles that aggregate, causing sample turbidity. Turbidity was measured spectrophotometrically as a function of absorbance at 340 nm. After an initial lag phase, lipoprotein sample turbidity increased as a function of reaction time and LTP concentration. Saturation was observed at longer times or higher LTP concentrations, indicating that a reaction end point had been reached. As the substrate HDLp concentration was increased relative to LDL, a saturable increase in LTP-induced lipoprotein sample turbidity was observed. When the LDL concentration was increased relative to HDLp, however, there was an initial production of turbidity but at higher concentrations the sample did not develop turbidity. Reaction progress was also dependent on temperature over the range 0-37°C. Taken together the results are consistent with the concept that LTP-mediated diacylglycerol transfer from HDLp to LDL creates unstable product LDL particles that aggregate. The assay method is advantageous because it employs relatively abundant, natural lipoprotein substrates, does not require prelabeling of donor lipid particles with radioactive or fluorescent lipids, and does not require separation of donor and acceptor after incubation. This is the first description of a lipid transfer assay that can be measured spectrophotometrically.

Circulation, 2006

The tyrosine kinase receptor erbB2 (or Her2 in humans) is a member of the epidermal growth factor... more The tyrosine kinase receptor erbB2 (or Her2 in humans) is a member of the epidermal growth factor receptor. It is highly expressed in many cancer types, and its overexpression is correlated with a ...

Blood, 2008

Background: Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma (NHL) with a prevalence o... more Background: Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma (NHL) with a prevalence of approximately 15,000 cases in the United States. Although current therapeutics extend longevity, the median survival is 3 to 5 years warranting continued investigation for newer therapeutics. MCL is characterized by cells with enhanced proliferation combined with impaired apoptosis characteristic of indolent lymphomas. Therefore, therapeutic approaches targeting transcription, translation, or cellular bioenergetics may prove to be more effective than therapies targeting DNA replication. In addition, therapeutic strategies that exploit the altered cellular metabolism of tumor cells may be beneficial. Nucleoside analogues have been used extensively in the treatment of hematologic malignancies and are selective for tumor cells. Our laboratories have developed two purine nucleoside analogues i.e. 8-chloro-adenosine (currently in clinical trials) and a congener, 8-amino-adenosine (8-NH2-Ado...

Blood, 2007

MCL, characterized by the t(11;14), results in the overexpression of cyclin D1, and typically has... more MCL, characterized by the t(11;14), results in the overexpression of cyclin D1, and typically has an aggressive clinical course. The disease is not curable by conventional therapy, and new modalities are needed. A MCL cell line, Granta, has been studied and has a complex karyotype and genetic alterations of cell cycle regulatory genes. ATRA is a metabolic derivative of retinoic acid (RA). Upon binding with ATRA, its receptors become transcriptionally activated and transactivate their target genes leading to cell growth arrest or apoptosis. We hypothesized that ATRA would lead to apoptosis or cell growth arrest in Granta MCL cells. We used ATRA nanodisks for increased solubilization and in vivo delivery. Reactive oxygen species (ROS) were measured with fluorescence-activated cell sorting (FACS) following incubation at 6 hours (h) and 24 h with ATRA (12.5–50nM). At 6 h, ATRA induced dose-dependent generation of ROS, which returned to baseline at 24 h. The levels of ROS in untreated co...

Blood, 2007

The cytotoxic activity of As2O3 in leukemia and myeloma has been shown to be mediated in part by ... more The cytotoxic activity of As2O3 in leukemia and myeloma has been shown to be mediated in part by ROS. We determined the mechanism of cytotoxicity of As2O3 in HL and NHL cell lines. Ramos, HF-1, SUDHL4 (NHL lines), and L428 (HL line) cells were cultured with increasing clinically relevant As2O3 concentrations (1.0mm-10mm) at 24-72 hours with and without the oxidizing agent, buthionine sulfoxime (BSO, 100mm), and with and without caspase inhibitors Z-VAD-FMK and Z-IETD-FMK. Apoptosis was measured by Annexin-V/propidium iodide (PI) staining and detected by flow cytometry (FACS). ROS was measured by oxidation of 2′7′ dichlorofluorescein diacetate (H2DCFDA) to Dichlorofluorescein (DCF) and analyzed by FACS. Immunoblots were performed for bcl-2, PARP, cleaved caspases 3, 8, 9, and mitogen activated protein kinase (MAPK) pathways (ERK, JNK, and p38 activation). As2O3 alone at 10mM resulted in dose- and time-dependent apoptosis in all cell lines (HL and NHL) with >75% annexin+/PI+ betwee...

Blood, 2007

We have reported that MGd, an expanded porphyrin and redox stress inducer, lowers p53 protein but... more We have reported that MGd, an expanded porphyrin and redox stress inducer, lowers p53 protein but not message in lymphoma cell lines. These results suggested that there is post-translational modification of p53 induced by MGd, and that this effect depends on the presence of ascorbate (Asc) or zinc (Zn). To expand these earlier studies, we measured the expression of oxidant and antioxidant genes in Ramos (Burkitt’s) cells. We incubated Ramos cells for 5 hours with MGd 100μM with or without Zn acetate (Zn, 100μM), Asc 100μM, and Nutlin-3 15μM. Following incubation, total RNA was isolated by the Qiagen method and dissolved in RNase-free water. 1.0 μg RNA was used for reverse transcription using the Taq DNA polymerase system. PCR amplification was performed at 94°C for 30 sec (denaturation), 55°C (annealing) and 72°C (extension) for 35 cycles. This was followed by an extension at 72°C for 10 minutes. Anti-sense primers and sense primers for SESN1(T2), SESN2, GPX1, CDKN1A, and PP1A were ...

Blood, 2010

3934 Background: Mantle cell lymphoma (MCL) is a pre–germinal center neoplasm characterized by cy... more 3934 Background: Mantle cell lymphoma (MCL) is a pre–germinal center neoplasm characterized by cyclin D1 overexpression resulting from translocation of the cyclin D1 gene on 11q13 to the promoter of the immunoglobulin heavy chain locus on 14q32. Since MCL is incurable with standard lymphoma therapies, new treatment approaches are needed that target specific biologic pathways. The bioactive polyphenol curcumin (Curc), derived from the rhizome of Curcuma longa Linn, has been shown to have pleiotropic activities related to its complex chemistry and its influence on multiple signaling pathways including NF-kB, Akt, Nrf2 and pathways involved in metastasis and angiogenesis. Curc has been shown to cause growth arrest and apoptosis of BKS-2 immature B-cell lymphoma by downregulating growth and survival promoting genes (Clin Immunol 1999; 93:152). However, because of poor aqueous solubility Curc has had limited clinical utility, so investigators have explored nanoparticle drug delivery appr...

Blood, 2009

2713 Poster Board II-689 Introduction: HIF-1 is a transcription factor that serves as a master re... more 2713 Poster Board II-689 Introduction: HIF-1 is a transcription factor that serves as a master regulator of cellular responses to hypoxia and regulates genes required for adaptation to hypoxia. Although the expression of HIF-1α subunit is constitutive, HIF-1α protein levels are regulated in response to oxygen tension. Under normoxic conditions, HIF-1α is degraded by the proteasome, and HIF-1 remains inactive. In hypoxia, HIF-1α is stabilized and forms a complex with HIF-1β that allows HIF-1 to function as a transcription factor. Thus, HIF-1α is activated only during hypoxia under normal physiologic conditions. By contrast, HIF-1α is frequently activated in cancer cells, including under normoxic conditions by oncogene products or impaired activity of tumor suppressor genes. We previously reported that there is constitutive stabilization of HIF-1α in many non-Hodgkin lymphoma (NHL) cell lines as well as among a significant fraction of diffuse large B-cell lymphoma (DLBCL) and follicul...

Blood, 2006

Disruption of the tumor suppressor p53 is a frequent event in malignant disorders, including lymp... more Disruption of the tumor suppressor p53 is a frequent event in malignant disorders, including lymphomas. Loss of constitutive low-level p53-dependent expression of anti-oxidant proteins could render cells more susceptable to the acute oxidant stress induced by oxidant generating agents such as MGd, bortezomib and rituximab. Alternatively, loss of p53 would render cells more resistant to apoptosis normally seen after strong activation of p53 activity in response to DNA damage. We hypothesized that the ROS generating expanded porphyrin, MGd, which we have previously shown to cause apoptosis in lymphoma and myeloma cells, results in loss of low-level, basal p53 expression, making cells more susceptable to oxidant stress. In order to test this hypothesis, we incubated Ramos, HIF-1 and SUDHL-4 lymphoma cells for 30, 60, 120 and 300 min with MGd (0.1–100 μM) with or without zinc acetate (Zn) and ascorbate. Following incubation, whole cell lysates were collected, electrophoresed on SDS-PAGE...

Blood, 2012

157 We report a nanoparticle-enabled therapeutic approach to B cell lymphoma using synthetic, hig... more 157 We report a nanoparticle-enabled therapeutic approach to B cell lymphoma using synthetic, high-density lipoprotein nanoparticles (HDL-NP). Like natural HDLs, biomimetic HDL-NPs target scavenger receptor type B-1 (SR-B1), a high-affinity HDL receptor expressed by lymphoma cells. Functionally, and unlike natural HDL, a gold nanoparticle template used to control HDL-NP synthesis enables differential manipulation of cellular cholesterol flux through SR-B1. Recent evidence in lymphoblasts and myeloblasts from patients with acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) demonstrates enhanced uptake of cholesterol through high-density lipoprotein (HDL) carriers, which may result in increased cell proliferation. We therefore hypothesized that by targeting SR-B1, we could manipulate cholesterol flux in lymphoma cells thereby targeting cellular signaling pathways that would lead to cell death and offer an innovative approach to the treatment of lymphoma and other cancer...

Blood, 2009

1698 Poster Board I-724 Background HIF-1á is a transcription factor that regulates gene expressi... more 1698 Poster Board I-724 Background HIF-1á is a transcription factor that regulates gene expression in response to decreases in cellular oxygenation (hypoxia). Genes activated by HIF are involved in glycolysis, glucose transport, angiogenesis, cell proliferation, cell migration, cell metabolism, and cell survival. Many of these genes confer protection against the consequences of oxygen deprivation while others enhance resistance to chemotherapy or radiotherapy. Clinically, evidence of elevated HIF-1á protein correlates with poor prognosis in lung, breast, colorectal, brain, pancreatic, ovarian, renal and bladder cancers. Our prior data found that constitutive expression of HIF-1á is enhanced in a set of established lymphoma cell lines (Evens et al, BJH, 2008), underscoring the potential impact of HIF in lymphoma. We also found that HIF-1á was stabilized in lymphoma specimens from patients with follicular lymphoma and DLBCL. These observations highlight a potential importance of H...

Anticancer research, Nov 1, 2017

The emerging field of nanotechnology meets the demands for innovative approaches in the diagnosis... more The emerging field of nanotechnology meets the demands for innovative approaches in the diagnosis and treatment of cancer. The nanoparticles are biocompatible and biodegradable and are made of a core, a particle that acts as a carrier, and one or more functional groups on the core which target specific sites. Nanotech in drug delivery includes nanodisks, High Density Lipoprotein nanostructures, liposomes, and gold nanoparticles. The fundamental advantages of nanoparticles are: improved delivery of water-insoluble drugs, targeted delivery, co-delivery of two or more drugs for combination therapy, and visualization of the drug delivery site by combining imaging system and a therapeutic drug. One of the potential applications of nanotechnology is in the treatment of cancer. Conventional methods for cancer treatments have included chemotherapy, surgery, or radiation. Early recognition and treatment of cancer with these approaches is still challenging. Innovative technologies are needed ...

International Journal of Molecular Sciences, 2018

Apoptosis, the cell’s natural mechanism for death, is a promising target for anticancer therapy. ... more Apoptosis, the cell’s natural mechanism for death, is a promising target for anticancer therapy. Both the intrinsic and extrinsic pathways use caspases to carry out apoptosis through the cleavage of hundreds of proteins. In cancer, the apoptotic pathway is typically inhibited through a wide variety of means including overexpression of antiapoptotic proteins and under-expression of proapoptotic proteins. Many of these changes cause intrinsic resistance to the most common anticancer therapy, chemotherapy. Promising new anticancer therapies are plant-derived compounds that exhibit anticancer activity through activating the apoptotic pathway.

Acta cardiologica, 1992

Serum ceruloplasmin levels were estimated in 81 patients within one week after an attack of acute... more Serum ceruloplasmin levels were estimated in 81 patients within one week after an attack of acute myocardial infarction. A total of 126 healthy subjects were taken as controls and investigated for this copper containing protein. Results showed that there is an elevation in the levels of serum ceruloplasmin in patients as compared to the controls. Ceruloplasmin levels showed a return to almost normal values in 54 follow-up cases of acute myocardial infarction during the fourth week after infarction.

Studies were performed to determine the effects of PTH and related compounds on phosphatidylcholi... more Studies were performed to determine the effects of PTH and related compounds on phosphatidylcholine (PC) hydrolysis in UMR-106 cells and the pathway by which the PTH effects occurred. The responses were compared with those of phorbol 12,13-dibutyrate (PDBu). Both bovine PTH-(1-34) (bPTH-(1-34)) and PDBu stimulated PC hydro- lysis within 10 min. Significant effects were elicited by concentrations of 0.3-1 nM bPTH-(1-34) and 5 nM PDBu. Dose-dependent increases were seen at higher concentrations of both compounds, however, the response to bPTH-(1-34) was reduced at 30 nM. Bovine or human PTH-(1-34) and human PTH-related peptide-(1-34) (hPTHrP-(1-34)) were equipotent in their effects, whereas bovine (Nle8,18Tyr34)PTH- (3-34) amide (bPTH-(3-34)) and hPTH-(1-31) amide (hPTH-(1-31)) were less potent than bPTH-(1-34). bPTH-(3-34) did not antagonize the effects of bPTH-(1-34). Down-regulation of protein kinase C isozymes by 24-h treatment with PDBu completely prevented the stimulatory effect...

Nanomedicine: Nanotechnology, Biology and Medicine, 2011

Nanodisks (ND) are nanoscale, disk-shaped phospholipid bilayers whose edge is stabilized by apoli... more Nanodisks (ND) are nanoscale, disk-shaped phospholipid bilayers whose edge is stabilized by apolipoproteins. In the present study, ND were formulated with the bioactive polyphenol, curcumin, at a 6:1 phospholipid:curcumin molar ratio. Atomic force microscopy revealed that curcumin-ND are particles with diameters <50 nm and thickness of a phospholipid bilayer. When formulated in ND, curcumin is water-soluble and gives rise to a characteristic absorbance spectrum with a peak centered at 420 nm. Fluorescence spectroscopy of curcumin-ND provided evidence of self-quenching. Incubation of curcumin-ND with empty-ND relieved the selfquenching, indicating redistribution of curcumin between curcumin loaded-and empty-ND. In HepG2 cells, curcumin-ND mediated enhanced cell growth inhibition compared to free curcumin. In a cell culture model of mantle cell lymphoma, curcumin-ND were a more potent inducer of apoptosis than free curcumin. The nanoscale size of the complexes, combined with their ability to solubilize curcumin, indicates ND may have in vivo therapeutic applications.

Leukemia & Lymphoma, 2011

Cellular Signalling, 2004

Parathyroid hormone (PTH) stimulates both bone formation and resorption by activating diverse ost... more Parathyroid hormone (PTH) stimulates both bone formation and resorption by activating diverse osteoblast signalling pathways. Upstream signalling for PTH stimulation of protein kinase C-a (PKCa) membrane translocation and subsequent expression of the proresorptive cytokine interleukin-6 (IL-6) was investigated in UMR-106 osteoblastic cells. PTH 1-34, PTH 3-34, PTHrP and PTH 1-31 stimulated PKCa translocation and IL-6 promoter activity. Pharmacologic intervention at the adenylyl cyclase (AC) pathway (forskolin, IBMX, PKI) failed to alter PTH 1-34-or PTH 3-34-stimulated PKCa translocation. The phosphoinositol-phospholipase C (PI-PLC) antagonist U73122 slightly decreased PTH 1-34-stimulated PKCa translocation; however, the control analogue U73343 acted similarly. Propranolol, an inhibitor of phosphatidic acid (PA) phosphohydrolase, decreased diacylglycerol (DAG) formation and attenuated PTH 1-34and PTH 3-34-stimulated PKCa translocation and IL-6 promoter activity, suggesting a phospholipase D (PLD)-dependent mechanism. This is the first demonstration that PLD-mediated signalling leads to both PKC-a translocation and IL-6 promoter activation in osteoblastic cells.

Arteriosclerosis, Thrombosis, and Vascular Biology, 1996

Genetic and dietary effects on LDL phenotypes, including predominant LDL particle diameter, LDL s... more Genetic and dietary effects on LDL phenotypes, including predominant LDL particle diameter, LDL size distribution, and non–HDL cholesterol and apoB concentrations, were investigated in 150 pedigreed baboons that are members of 19 sire groups. Baboons were fed a sequence of three defined diets differing in levels of fat and cholesterol. Increasing dietary fat had relatively little effect on two measures of LDL particle size. However, increasing the level of cholesterol in the diet resulted in larger increases of the predominant LDL particle diameters and in the proportion of stain on LDLs >28 nm. As expected, apoB and non–HDL cholesterol concentrations significantly increased when levels of dietary fat and cholesterol were increased. Correlations among the LDL phenotypes suggested that several different aspects of the LDL phenotype were captured by the four LDL measures across the three diets. Genetic effects indicated by sire group membership were significant both for expression ...

Analytical Biochemistry, 1992

A novel method to assay insect plasma lipid transfer particle (LTP) activity has been developed t... more A novel method to assay insect plasma lipid transfer particle (LTP) activity has been developed that employs insect high density lipophorin (HDLp) and human low density lipoprotein (LDL) as donor/acceptor substrate particles. At a 3:1 or greater HDLp:LDL protein ratio, LTP-mediated net vectorial transfer of diacylglycerol from lipophorin to LDL produces destabilized LDL particles that aggregate, causing sample turbidity. Turbidity was measured spectrophotometrically as a function of absorbance at 340 nm. After an initial lag phase, lipoprotein sample turbidity increased as a function of reaction time and LTP concentration. Saturation was observed at longer times or higher LTP concentrations, indicating that a reaction end point had been reached. As the substrate HDLp concentration was increased relative to LDL, a saturable increase in LTP-induced lipoprotein sample turbidity was observed. When the LDL concentration was increased relative to HDLp, however, there was an initial production of turbidity but at higher concentrations the sample did not develop turbidity. Reaction progress was also dependent on temperature over the range 0-37°C. Taken together the results are consistent with the concept that LTP-mediated diacylglycerol transfer from HDLp to LDL creates unstable product LDL particles that aggregate. The assay method is advantageous because it employs relatively abundant, natural lipoprotein substrates, does not require prelabeling of donor lipid particles with radioactive or fluorescent lipids, and does not require separation of donor and acceptor after incubation. This is the first description of a lipid transfer assay that can be measured spectrophotometrically.