sheetal pundir | McGill University (original) (raw)
Papers by sheetal pundir
Scientific Reports
In subretinal inflammation, activated mononuclear phagocytes (MP) play a key role in the progress... more In subretinal inflammation, activated mononuclear phagocytes (MP) play a key role in the progression of retinopathies. Little is known about the mechanism involved in the loss of photoreceptors leading to vision impairment. Studying retinal damage induced by photo-oxidative stress, we observed that cluster of differentiation 36 (CD36)-deficient mice featured less subretinal MP accumulation and attenuated photoreceptor degeneration. Moreover, treatment with a CD36-selective azapeptide ligand (MPE-001) reduced subretinal activated MP accumulation in wild type mice and preserved photoreceptor layers and function as assessed by electroretinography in a CD36-dependent manner. The azapeptide modulated the transcriptome of subretinal activated MP by reducing proinflammatory markers. In isolated MP, MPE-001 induced dissociation of the CD36-Toll-like receptor 2 (TLR2) oligomeric complex, decreasing nuclear factor-kappa B (NF-κB) and NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. In addition, MPE-001 caused an aerobic metabolic shift in activated MP, involving peroxisome proliferator-activated receptor-γ (PPAR-γ) activation, which in turn mitigated inflammation. Accordingly, PPAR-γ inhibition blocked the cytoprotective effect of MPE-001 on photoreceptor apoptosis elicited by activated MP. By altering activated MP metabolism, MPE-001 decreased immune responses to alleviate subsequent inflammation-dependent neuronal injury characteristic of various vision-threatening retinal disorders.
The American Journal of Pathology
Journal of Enzyme Inhibition and Medicinal Chemistry
Scientific reports, Jan 8, 2018
Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ developm... more Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1β participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1β associated with preterm birth (PTB) in retinal vasculopathy (independent of hyperoxia) is unknown. Using a murine model of PTB induced with IL-1β injection in utero, we studied consequent retinal and choroidal vascular development; in this process we evaluated the efficacy of IL-1R antagonists. Eyes of foetuses exposed only to IL-1β displayed high levels of pro-inflammatory genes, and a persistent postnatal infiltration of inflammatory cells. This prolonged inflammatory response was associated with: (1) a marked delay in retinal vessel growth; (2) long-lasting thinning of the choroid; and (3) long-term morphological and functional alterations of the retina. Antenatal administr...
European journal of medicinal chemistry, 2018
In an attempt to develop effective and safe anticancer agents, we designed, synthesized and exami... more In an attempt to develop effective and safe anticancer agents, we designed, synthesized and examined 23 novel quinacrine (QC) derivatives by combining the 9-aminoacridine scaffold and the [1,3]thiazinan-4-ones group. Most of these hybrids showed strong anticancer activities, among which 3-(3-(6-chloro-2-methoxyacridin-9-ylamino)propyl)-2-(thiophen-2-yl)-1,3-thiazinan-4-one (25; VR151) effectively killed many different cancer cell types, including eight breast cancer cell lines with different genetic background, two prostate cancer and two lung cancer cell lines. In contrast, compound 25 is less effective against non-cancer cells, suggesting it may be less toxic to humans. Our data showed that cancer cells are arrested in S phase for a prolonged period due to the down-regulation of DNA replication, leading to eventual cell death. We have also shown that the S phase arrest may be resulted by the down-regulation of cyclin A coupled with the continued up-regulation of cyclin E, which co...
The Journal of Immunology, 2017
Preterm birth (PTB) is commonly accompanied by in utero fetal inflammation, and existing tocolyti... more Preterm birth (PTB) is commonly accompanied by in utero fetal inflammation, and existing tocolytic drugs do not target fetal inflammatory injury. Of the candidate proinflammatory mediators, IL-1 appears central and is sufficient to trigger fetal loss. Therefore, we elucidated the effects of antenatal IL-1 exposure on postnatal development and investigated two IL-1 receptor antagonists, the competitive inhibitor anakinra (Kineret) and a potent noncompetitive inhibitor 101.10, for efficacy in blocking IL-1 actions. Antenatal exposure to IL-1b induced Tnfa, Il6, Ccl2, Pghs2, and Mpges1 expression in placenta and fetal membranes, and it elevated amniotic fluid IL-1b, IL-6, IL-8, and PGF 2a , resulting in PTB and marked neonatal mortality. Surviving neonates had increased Il1b, Il6, Il8, Il10, Pghs2, Tnfa, and Crp expression in WBCs, elevated plasma levels of IL-1b, IL-6, and IL-8, increased IL-1b, IL-6, and IL-8 in fetal lung, intestine, and brain, and morphological abnormalities: e.g., disrupted lung alveolarization, atrophy of intestinal villus and colonresident lymphoid follicle, and degeneration and atrophy of brain microvasculature with visual evoked potential anomalies. Late gestation treatment with 101.10 abolished these adverse outcomes, whereas Kineret exerted only modest effects and no benefit for gestation length, neonatal mortality, or placental inflammation. In a LPS-induced model of infection-associated PTB, 101.10 prevented PTB, neonatal mortality, and fetal brain inflammation. There was no substantive deviation in postnatal growth trajectory or adult body morphometry after antenatal 101.10 treatment. The results implicate IL-1 as an important driver of neonatal morbidity in PTB and identify 101.10 as a safe and effective candidate therapeutic.
Since Bortezomib®, a proteasome inhibitor, was approved by US FDA for the treatment of multiple m... more Since Bortezomib®, a proteasome inhibitor, was approved by US FDA for the treatment of multiple myeloma in 2003, proteasome is recognized as one of the most promising targets for cancer therapeutics. The proteasomes play a critical role in regulating the level of cellular proteins and recycling damaged and misfolded proteins. Although the activity of the proteasome is essential for normal cells, it is especially critical for the proliferation and survival of cancer cells. In an attempt to develop effective and safe proteasome inhibitor-based anticancer drugs, the Lee laboratory created a chemical library by a hybrid approach using a 4-piperazinylquinoline scaffold and a sulfonyl phamarcophore. It is known that the chloroquine scaffold possesses a weak proteasome inhibition activity, and chloroquine itself preferentially kills malignant cells over noncancer cells, alone or in combination with other therapeutics. To identify compounds with desirable anticancer activities, I have screened the aforementioned chemical library. The screening yielded several hits with substantial efficacy and selectivity against malignant cells. In this thesis, I describe the functional mechanism of VR23, one of the most promising compounds identified from my screening, as it kills cancer cells up to 17 fold more effectively than non-cancer cells. Molecular docking and substrate competition studies revealed that VR23 binds to the β2 peptide of the 20S proteasome catalytic subunit. The IC 50 value of VR23 in inhibiting trypsin-like proteasome activity is 1.0 nM. VR23 is also substantially effective in inhibiting chymotrypsin-like proteasome activity (IC 50 , 50-100 nM). The inhibition of proteasome activity by VR23 led to the accumulation of ubiquitinated cyclin E at centrosomes. This, in turn, induces abnormal ii centrosome amplification by a de novo centrosome synthesis pathway in cancer cells, but not in non-cancer cells. The presence of multiple centrosomes in single cancer cells results in cell cycle arrest at prometaphase and, eventually, cell death by apoptosis. Thus, VR23 possesses a very desirable property as a safe anticancer drug. iii ACKNOWLEDGEMENTS First and foremost I would like to thank my research supervisor, Dr. Hoyun Lee, for giving me this opportunity to work in his lab. I thank him for always taking me seriously and most importantly for respecting my opinions and ideas and giving me the freedom to make errors. His unbounded enthusiasm transformed the project into an exciting work. I have learned much more than I ever thought possible in the short time since I have known him. I thank him for his patience and for always keeping his "door open". I learnt to always see the big picture and above all to enjoy working in the lab.
The proteasome is clinically validated as a target for cancer therapeutics. However, proteasome-i... more The proteasome is clinically validated as a target for cancer therapeutics. However, proteasome-inhibitory agents that are cancer selective have yet to be developed. In this study, we report the identification of a safe and effective proteasome inhibitor with selective anticancer properties. We screened a chemical library constructed using a hybrid approach that incorporated a 4-piperazinylquinoline scaffold and a sulfonyl phamarcophore. From this library, we identified 7-chloro-4-(4-(2,4-dinitrophenylsulfonyl)piperazin-1-yl)quinoline (VR23) as a small molecule that potently inhibited the activities of trypsin-like proteasomes (IC 50 ¼ 1 nmol/L), chymotrypsin-like proteasomes (IC 50 ¼ 50-100 nmol/L), and caspase-like proteasomes (IC 50 ¼ 3 mmol/L). Data from molecular docking and substrate competition assays established that the primary molecular target of VR23 was b2 of the 20S proteasome catalytic subunit. Notably, VR23 was structurally distinct from other known proteasome inhibitors and selectively killed cancer cells by apoptosis, with little effect on noncancerous cells. Mechanistic investigations showed that cancer cells exposed to VR23 underwent an abnormal centrosome amplification cycle caused by the accumulation of ubiquitinated cyclin E. In combinations with the clinically approved chymotrypsin-like proteasome inhibitor bortezomib, VR23 produced a synergistic effect in killing multiple myeloma cells, including those that were resistant to bortezomib. VR23 was effective in vivo in controlling multiple myelomas and metastatic breast cancer cells, in the latter case also enhancing the antitumor activity of paclitaxel while reducing its side effects. Overall, our results identify VR23 as a structurally novel proteasome inhibitor with desirable properties as an anticancer agent. Cancer Res; 75(19); 4164-75. Ó2015 AACR.
Scientific Reports
In subretinal inflammation, activated mononuclear phagocytes (MP) play a key role in the progress... more In subretinal inflammation, activated mononuclear phagocytes (MP) play a key role in the progression of retinopathies. Little is known about the mechanism involved in the loss of photoreceptors leading to vision impairment. Studying retinal damage induced by photo-oxidative stress, we observed that cluster of differentiation 36 (CD36)-deficient mice featured less subretinal MP accumulation and attenuated photoreceptor degeneration. Moreover, treatment with a CD36-selective azapeptide ligand (MPE-001) reduced subretinal activated MP accumulation in wild type mice and preserved photoreceptor layers and function as assessed by electroretinography in a CD36-dependent manner. The azapeptide modulated the transcriptome of subretinal activated MP by reducing proinflammatory markers. In isolated MP, MPE-001 induced dissociation of the CD36-Toll-like receptor 2 (TLR2) oligomeric complex, decreasing nuclear factor-kappa B (NF-κB) and NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. In addition, MPE-001 caused an aerobic metabolic shift in activated MP, involving peroxisome proliferator-activated receptor-γ (PPAR-γ) activation, which in turn mitigated inflammation. Accordingly, PPAR-γ inhibition blocked the cytoprotective effect of MPE-001 on photoreceptor apoptosis elicited by activated MP. By altering activated MP metabolism, MPE-001 decreased immune responses to alleviate subsequent inflammation-dependent neuronal injury characteristic of various vision-threatening retinal disorders.
The American Journal of Pathology
Journal of Enzyme Inhibition and Medicinal Chemistry
Scientific reports, Jan 8, 2018
Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ developm... more Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1β participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1β associated with preterm birth (PTB) in retinal vasculopathy (independent of hyperoxia) is unknown. Using a murine model of PTB induced with IL-1β injection in utero, we studied consequent retinal and choroidal vascular development; in this process we evaluated the efficacy of IL-1R antagonists. Eyes of foetuses exposed only to IL-1β displayed high levels of pro-inflammatory genes, and a persistent postnatal infiltration of inflammatory cells. This prolonged inflammatory response was associated with: (1) a marked delay in retinal vessel growth; (2) long-lasting thinning of the choroid; and (3) long-term morphological and functional alterations of the retina. Antenatal administr...
European journal of medicinal chemistry, 2018
In an attempt to develop effective and safe anticancer agents, we designed, synthesized and exami... more In an attempt to develop effective and safe anticancer agents, we designed, synthesized and examined 23 novel quinacrine (QC) derivatives by combining the 9-aminoacridine scaffold and the [1,3]thiazinan-4-ones group. Most of these hybrids showed strong anticancer activities, among which 3-(3-(6-chloro-2-methoxyacridin-9-ylamino)propyl)-2-(thiophen-2-yl)-1,3-thiazinan-4-one (25; VR151) effectively killed many different cancer cell types, including eight breast cancer cell lines with different genetic background, two prostate cancer and two lung cancer cell lines. In contrast, compound 25 is less effective against non-cancer cells, suggesting it may be less toxic to humans. Our data showed that cancer cells are arrested in S phase for a prolonged period due to the down-regulation of DNA replication, leading to eventual cell death. We have also shown that the S phase arrest may be resulted by the down-regulation of cyclin A coupled with the continued up-regulation of cyclin E, which co...
The Journal of Immunology, 2017
Preterm birth (PTB) is commonly accompanied by in utero fetal inflammation, and existing tocolyti... more Preterm birth (PTB) is commonly accompanied by in utero fetal inflammation, and existing tocolytic drugs do not target fetal inflammatory injury. Of the candidate proinflammatory mediators, IL-1 appears central and is sufficient to trigger fetal loss. Therefore, we elucidated the effects of antenatal IL-1 exposure on postnatal development and investigated two IL-1 receptor antagonists, the competitive inhibitor anakinra (Kineret) and a potent noncompetitive inhibitor 101.10, for efficacy in blocking IL-1 actions. Antenatal exposure to IL-1b induced Tnfa, Il6, Ccl2, Pghs2, and Mpges1 expression in placenta and fetal membranes, and it elevated amniotic fluid IL-1b, IL-6, IL-8, and PGF 2a , resulting in PTB and marked neonatal mortality. Surviving neonates had increased Il1b, Il6, Il8, Il10, Pghs2, Tnfa, and Crp expression in WBCs, elevated plasma levels of IL-1b, IL-6, and IL-8, increased IL-1b, IL-6, and IL-8 in fetal lung, intestine, and brain, and morphological abnormalities: e.g., disrupted lung alveolarization, atrophy of intestinal villus and colonresident lymphoid follicle, and degeneration and atrophy of brain microvasculature with visual evoked potential anomalies. Late gestation treatment with 101.10 abolished these adverse outcomes, whereas Kineret exerted only modest effects and no benefit for gestation length, neonatal mortality, or placental inflammation. In a LPS-induced model of infection-associated PTB, 101.10 prevented PTB, neonatal mortality, and fetal brain inflammation. There was no substantive deviation in postnatal growth trajectory or adult body morphometry after antenatal 101.10 treatment. The results implicate IL-1 as an important driver of neonatal morbidity in PTB and identify 101.10 as a safe and effective candidate therapeutic.
Since Bortezomib®, a proteasome inhibitor, was approved by US FDA for the treatment of multiple m... more Since Bortezomib®, a proteasome inhibitor, was approved by US FDA for the treatment of multiple myeloma in 2003, proteasome is recognized as one of the most promising targets for cancer therapeutics. The proteasomes play a critical role in regulating the level of cellular proteins and recycling damaged and misfolded proteins. Although the activity of the proteasome is essential for normal cells, it is especially critical for the proliferation and survival of cancer cells. In an attempt to develop effective and safe proteasome inhibitor-based anticancer drugs, the Lee laboratory created a chemical library by a hybrid approach using a 4-piperazinylquinoline scaffold and a sulfonyl phamarcophore. It is known that the chloroquine scaffold possesses a weak proteasome inhibition activity, and chloroquine itself preferentially kills malignant cells over noncancer cells, alone or in combination with other therapeutics. To identify compounds with desirable anticancer activities, I have screened the aforementioned chemical library. The screening yielded several hits with substantial efficacy and selectivity against malignant cells. In this thesis, I describe the functional mechanism of VR23, one of the most promising compounds identified from my screening, as it kills cancer cells up to 17 fold more effectively than non-cancer cells. Molecular docking and substrate competition studies revealed that VR23 binds to the β2 peptide of the 20S proteasome catalytic subunit. The IC 50 value of VR23 in inhibiting trypsin-like proteasome activity is 1.0 nM. VR23 is also substantially effective in inhibiting chymotrypsin-like proteasome activity (IC 50 , 50-100 nM). The inhibition of proteasome activity by VR23 led to the accumulation of ubiquitinated cyclin E at centrosomes. This, in turn, induces abnormal ii centrosome amplification by a de novo centrosome synthesis pathway in cancer cells, but not in non-cancer cells. The presence of multiple centrosomes in single cancer cells results in cell cycle arrest at prometaphase and, eventually, cell death by apoptosis. Thus, VR23 possesses a very desirable property as a safe anticancer drug. iii ACKNOWLEDGEMENTS First and foremost I would like to thank my research supervisor, Dr. Hoyun Lee, for giving me this opportunity to work in his lab. I thank him for always taking me seriously and most importantly for respecting my opinions and ideas and giving me the freedom to make errors. His unbounded enthusiasm transformed the project into an exciting work. I have learned much more than I ever thought possible in the short time since I have known him. I thank him for his patience and for always keeping his "door open". I learnt to always see the big picture and above all to enjoy working in the lab.
The proteasome is clinically validated as a target for cancer therapeutics. However, proteasome-i... more The proteasome is clinically validated as a target for cancer therapeutics. However, proteasome-inhibitory agents that are cancer selective have yet to be developed. In this study, we report the identification of a safe and effective proteasome inhibitor with selective anticancer properties. We screened a chemical library constructed using a hybrid approach that incorporated a 4-piperazinylquinoline scaffold and a sulfonyl phamarcophore. From this library, we identified 7-chloro-4-(4-(2,4-dinitrophenylsulfonyl)piperazin-1-yl)quinoline (VR23) as a small molecule that potently inhibited the activities of trypsin-like proteasomes (IC 50 ¼ 1 nmol/L), chymotrypsin-like proteasomes (IC 50 ¼ 50-100 nmol/L), and caspase-like proteasomes (IC 50 ¼ 3 mmol/L). Data from molecular docking and substrate competition assays established that the primary molecular target of VR23 was b2 of the 20S proteasome catalytic subunit. Notably, VR23 was structurally distinct from other known proteasome inhibitors and selectively killed cancer cells by apoptosis, with little effect on noncancerous cells. Mechanistic investigations showed that cancer cells exposed to VR23 underwent an abnormal centrosome amplification cycle caused by the accumulation of ubiquitinated cyclin E. In combinations with the clinically approved chymotrypsin-like proteasome inhibitor bortezomib, VR23 produced a synergistic effect in killing multiple myeloma cells, including those that were resistant to bortezomib. VR23 was effective in vivo in controlling multiple myelomas and metastatic breast cancer cells, in the latter case also enhancing the antitumor activity of paclitaxel while reducing its side effects. Overall, our results identify VR23 as a structurally novel proteasome inhibitor with desirable properties as an anticancer agent. Cancer Res; 75(19); 4164-75. Ó2015 AACR.