Fotis Asimakopoulos - Academia.edu (original) (raw)

Papers by Fotis Asimakopoulos

$Research paper thumbnail of Research Article Tumoricidal Effects of Macrophage-Activating Immunotherapy in a Murine Model of Relapsed/Refractory Multiple Myeloma$

Myeloma remains a virtually incurable malignancy. The inev-itable evolution of multidrug-resistan... more Myeloma remains a virtually incurable malignancy. The inev-itable evolution of multidrug-resistant clones and widespread clonal heterogeneity limit the potential of traditional and novel therapies to eliminateminimal residual disease (MRD), a reliable harbinger of relapse. Here, we show potent anti-myeloma acti-vity of macrophage-activating immunotherapy (aCD40þCpG) that resulted in prolongation of progression-free survival (PFS) and overall survival (OS) in an immunocompetent, preclinical-ly validated, transplant-based model of multidrug-resistant, relapsed/refractory myeloma (t-VkMYC). aCD40þCpG was effective in vivo in the absence of cytolytic natural killer, T, or B cells and resulted in expansion ofM1-polarized (cytolytic/tumor-icidal)macrophages in the bonemarrow.Moreover, we show that concurrent loss/inhibition of Tpl2 kinase (Cot, Map3k8), a MAP3K that is recruited to activated CD40 complex and regulates macrophage activation/cytokine production, potentiated direct, ex vivo ...

Journal for ImmunoTherapy of Cancer, 2021

BackgroundStimulatory dendritic cells (SDC), enriched within the Batf3-DC lineage (also known as ... more BackgroundStimulatory dendritic cells (SDC), enriched within the Batf3-DC lineage (also known as conventional type 1 DC, cDC1), engage in productive interactions with CD8+ effectors along tumor-stroma boundaries. This puzzling pattern of T-cell-DC localization has been interpreted as ”tumor-exclusion”, limiting anti-tumor immunity. To understand this paradox, we hypothesized that dynamic matrix remodeling at the invasive margin generates unique activation and cell-fate cues critical for Batf3-DC homeostasis.MethodsWe studied immunocompetent tumor models of lung carcinoma, breast carcinoma, melanoma and multiple myeloma. For mechanistic experiments, we generated novel Vcan-targeted models through CRISPR-Cas9 targeting. We delineated DC subsets through multi-parametric flow cytometry and tumor immune contexture through mass cytometry. Batf3-DC cellular models included MutuDC1940 immortalized DC and iCD103 primary cells. TCGA data were mined for human validation.ResultsWe find that CD8...

Advances in Experimental Medicine and Biology, 2020

Versican is an extracellular matrix proteoglycan with nonredundant roles in diverse biological an... more Versican is an extracellular matrix proteoglycan with nonredundant roles in diverse biological and cellular processes, ranging from embryonic development to adult inflammation and cancer. Versican is essential for cardiovascular morphogenesis, neural crest migration, and skeletal development during embryogenesis. In the adult, versican acts as an inflammation "amplifier" and regulator of immune cell activation and cytokine production. Increased versican expression has been observed in a wide range of malignant tumors and has been associated with poor patient outcomes. The main sources of versican production in the tumor microenvironment include accessory cells (myeloid cells and stromal components) and, in some contexts, the tumor cells themselves. Versican has been implicated in several classical hallmarks of cancer such as proliferative signaling, evasion of growth suppressor signaling, resistance to cell death, angiogenesis, and tissue invasion and metastasis. More recently, versican has been implicated in escape from tumor immune surveillance, e.g., through dendritic cell dysfunction. Versican's multiple contributions to benign and malignant biological processes are further diversified through the generation of versican-derived bioactive proteolytic fragments (matrikines), with versikine being the most studied to date. Versican and versican-derived matrikines hold promise as targets in the management of inflammatory and malignant conditions as well as in the development of novel predictive and prognostic biomarkers.

Cancer Research, 2020

The impact of tumor matrix remodeling to the generation of an “inflamed” microenvironment that mo... more The impact of tumor matrix remodeling to the generation of an “inflamed” microenvironment that modulates responses to immunotherapy is unclear. Versican (VCAN) is a chondroitin sulphate matrix proteoglycan that promotes tolerogenic polarization of intratumoral DC through Toll-like receptor 2 (TLR2). Proteolytic processing of VCAN releases a bioactive N-terminal fragment (matrikine), versikine. In contrast to the tolerogenic actions of parental VCAN, versikine triggers IRF8-dependent transcription in myeloid cells and promotes Batf3-dendritic cell (DC) generation from FLT3L-mobilized bone marrow progenitors in vitro. Consistent with the Batf3-promoting effects of versikine, VCAN proteolysis correlates with T-cell infiltration across multiple cancers.The aims were to 1. define the impact of versikine on the intratumoral myeloid repertoire in vivo and 2. to define the efficacy of versikine as a vaccine adjuvant.4T1 breast carcinoma and Lewis Lung Carcinoma (LLC) empty vector (EV)- and ...

Journal of Clinical Oncology, 2017

e15082 Background: Colorectal cancer (CRC) originates within immunologically complex microenviron... more e15082 Background: Colorectal cancer (CRC) originates within immunologically complex microenvironments. To date the benefits of immunotherapy have been modest except in neoantigen-laden mismatch repair (MMR)-deficient tumors. Approaches to enhance tumor-infiltrating lymphocytes (TILS) in the tumor bed may substantially augment clinical immunotherapy responses. Proteolysis of the tolerogenic matrix proteoglycan versican (VCAN) generates a bioactive fragment, versikine, with putative immunostimulatory activities. Methods: Matched normal and CRC tissue samples were collected from 122 patients with cancers across all stages and locations throughout the colon and rectum. These samples were stained for VCAN, αDPEAAE (neoepitope generated in cleaving VCAN to versikine), and CD8 and scored by a pathologist. Tumors were classified as VCAN proteolysis-predominant (VPP) if their staining for total VCAN staining intensity was < 1+ and staining for VCAN proteolysis (αDPEAAE antibody) was >...

Blood, 2019

Regulated proteolysis of the tolerogenic matrix proteoglycan versican (VCAN) through the actions ... more Regulated proteolysis of the tolerogenic matrix proteoglycan versican (VCAN) through the actions of ADAMTS-proteases, is associated with enhanced CD8+ infiltration in both hematopoietic and solid tumors. However, it is unclear whether the enhanced CD8+ infiltration results from proteolysis-mediated depletion of precursor VCAN at the tumor site or from generation of bioactive proteolytic fragments ("matrikines") (e.g., the 441-aa N-terminal fragment of V1-VCAN isoform, versikine). We have previously shown that versikine promotes Batf3-dendritic cell (DC) generation from FLT3L-mobilized bone marrow (BM) progenitors in vitro. However, the effects of versikine in DC homeostasis in the tumor microenvironment in vivo are unknown. To investigate the effects of versikine in DC homeostasis in vivo, we utilized the first Ras-driven myeloma (MM) model (VQ model- Rajagopalan et al., Blood 132:1006, 2018) as well as transplantable solid tumor models in both C57BL/6J (LLC lung carcinoma...

Leukemia & Lymphoma, 2019

Journal for immunotherapy of cancer, Jan 3, 2018

Recent advances in our understanding of the dynamics of cellular cross-talk have highlighted the ... more Recent advances in our understanding of the dynamics of cellular cross-talk have highlighted the significance of host-versus-tumor effect that can be harnessed with immune therapies. Tumors exploit immune checkpoints to evade adaptive immune responses. Cancer immunotherapy has witnessed a revolution in the past decade with the development of immune checkpoint inhibitors (ICIs), monoclonal antibodies against cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) or their ligands, such as PD1 ligand 1 (PD-L1). ICIs have been reported to have activity against a broad range of tumor types, in both solid organ and hematologic malignancy contexts. However, less than one-third of the patients achieve a durable and meaningful treatment response. Expression of immune checkpoint ligands (e.g., PD-L1), mutational burden and tumor-infiltrating lymphocytes are currently used as biomarkers for predicting response to ICIs. However, they do not reliably predict which p...

Journal of immunology (Baltimore, Md. : 1950), Sep 1, 2017

Colorectal cancer originates within immunologically complex microenvironments. To date, the benef... more Colorectal cancer originates within immunologically complex microenvironments. To date, the benefits of immunotherapy have been modest, except in neoantigen-laden mismatch repair-deficient tumors. Approaches to enhance tumor-infiltrating lymphocytes in the tumor bed may substantially augment clinical immunotherapy responses. In this article, we report that proteolysis of the tolerogenic matrix proteoglycan versican (VCAN) strongly correlated with CD8(+) T cell infiltration in colorectal cancer, regardless of mismatch repair status. Tumors displaying active VCAN proteolysis and low total VCAN were associated with robust (10-fold) CD8(+) T cell infiltration. Tumor-intrinsic WNT pathway activation was associated with CD8(+) T cell exclusion and VCAN accumulation. In addition to regulating VCAN levels at the tumor site, VCAN proteolysis results in the generation of bioactive fragments with novel functions (VCAN-derived matrikines). Versikine, a VCAN-derived matrikine, enhanced the gener...

Handbook of Experimental Pharmacology, 2017

Multiple myeloma (MM) is an incurable hematopoietic cancer that is characterized by malignant pla... more Multiple myeloma (MM) is an incurable hematopoietic cancer that is characterized by malignant plasma cell infiltration of the bone marrow and/or extramedullary sites. Multi-modality approaches including "novel agents," traditional chemotherapy, and/or stem cell transplantation are used in MM therapy. Drug resistance, however, ultimately develops and the disease remains incurable for the vast majority of patients. In this chapter, we review both tumor cell-autonomous and non-autonomous (microenvironment-dependent) mechanisms of drug resistance. MM provides an attractive paradigm highlighting a number of current concepts and challenges in oncology. Firstly, identification of MM cancer stem cells and their unique drug resistance attributes may provide rational avenues towards MM eradication and cure. Secondly, the oligoclonal evolution of MM and alternation of "clonal tides" upon therapy challenge our current understanding of treatment responses. Thirdly, the success of MM "novel agents" provides exemplary evidence for the impact of therapies that target the immune and non-immune microenvironment. Fourthly, the rapid pace of drug approvals for MM creates an impetus for development of precision medicine strategies and biomarkers that promote efficacy and mitigate toxicity and cost. While routine cure of the disease remains the ultimate and yet unattainable prize, MM advances in the last 10-15 years have provided an astounding paradigm for the treatment of blood cancers in the modern era and have radically transformed patient outcomes.

Journal of leukocyte biology, Aug 2, 2017

The last 10-15 years have witnessed a revolution in treating multiple myeloma, an incurable cance... more The last 10-15 years have witnessed a revolution in treating multiple myeloma, an incurable cancer of Ab-producing plasma cells. Advances in myeloma therapy were ushered in by novel agents that remodel the myeloma immune microenvironment. The first generation of novel agents included immunomodulatory drugs (thalidomide analogs) and proteasome inhibitors that target crucial pathways that regulate immunity and inflammation, such as NF-κB. This paradigm continued with the recent regulatory approval of mAbs (elotuzumab, daratumumab) that impact both tumor cells and associated immune cells. Moreover, recent clinical data support checkpoint inhibition immunotherapy in myeloma. With the success of these agents has come the growing realization that the myeloid infiltrate in myeloma lesions-what we collectively call the myeloid-in-myeloma compartment-variably sustains or deters tumor cells by shaping the inflammatory milieu of the myeloma niche and by promoting or antagonizing immune-modulat...

Blood, Aug 3, 2016

Myeloma immunosurveillance remains incompletely understood. We have demonstrated proteolytic proc... more Myeloma immunosurveillance remains incompletely understood. We have demonstrated proteolytic processing of the matrix proteoglycan, versican, in myeloma tumors. Whereas intact versican exerts tolerogenic activities through Toll-like receptor (TLR)-2 binding, the immunoregulatory consequences of versican proteolysis remain unknown. Here we show that human myeloma tumors displaying CD8+ infiltration/aggregates underwent versican proteolysis at a site predicted to generate a glycosaminoglycan-bereft N-terminal fragment, versikine Myeloma-associated macrophages (MAM), but not tumor cells, produced V1-versican, the precursor to versikine, whereas stromal cell-derived ADAMTS1 was the most robustly expressed versican-degrading protease. Purified versikine induced early expression of inflammatory cytokines IL1β and IL6 by human myeloma marrow-derived MAM. We show that versikine signals through pathways both dependent and independent of Tpl2 kinase, a key regulator of NFκB1-mediated MAPK act...

American journal of cancer research, 2015

Neuroblastoma (NB) is the most common extracranial solid tumor in children and is associated with... more Neuroblastoma (NB) is the most common extracranial solid tumor in children and is associated with high mortality in advanced stages. Survivors suffer from long-term treatment-related sequelae. Thus, new targeted treatment options are urgently needed. 18-(p-[(127)I] iodophenyl) octadecyl phosphocholine (CLR1404) is a novel, broadly tumor targeted small molecule drug suitable for intravenous injection with highly selective tumor uptake. As a carrier molecule for radioactive iodine, CLR1404 is in clinical trials as cancer imaging agent and radiotherapeutic drug. Chemically, CLR1404 belongs to the anti-tumor alkyl phospholipids, a class of drugs known to have intrinsic cytotoxic effects on cancer cells. Therefore, we hypothesized that CLR1404 could be a tumor-targeted anti-cancer agent for neuroblastoma, and investigated its effect in vitro and in vivo. CLR1404 was taken up by NB cells in a highly tumor-selective manner both in vitro and in vivo, confirmed by flow cytometry and PET/CT i...

OncoImmunology, 2015

Myeloma remains incurable despite recent therapeutic advances. We propose that minimal residual d... more Myeloma remains incurable despite recent therapeutic advances. We propose that minimal residual disease following cytoreductive therapy may be controlled through re-education of myeloid cells to elicit tumoricidal activity. We review work from our laboratory and others highlighting aspects of macrophagemyeloma cell crosstalk as well as strategies for therapeutic macrophage reprogramming.

Journal of Biological Chemistry, 2015

B cell malignancies comprise a diverse group of cancers that proliferate in lymph nodes, bone mar... more B cell malignancies comprise a diverse group of cancers that proliferate in lymph nodes, bone marrow, and peripheral blood. SIRT3 (sirtuin 3) is the major deacetylase within the mitochondrial matrix that promotes aerobic metabolism and controls reactive oxygen species (ROS) by deacetylating and activating isocitrate dehydrogenase 2 (IDH2) and superoxide dismutase 2 (SOD2). There is controversy as to whether SIRT3 acts as an oncogene or a tumor suppressor, and here we investigated its role in B cell malignancies. In mantle cell lymphoma patient samples, we found that lower SIRT3 protein expression was associated with worse overall survival. Further, SIRT3 protein expression was reduced in chronic lymphocytic leukemia primary samples and malignant B cell lines compared to primary B cells from healthy donors. This lower level of expression correlated with hyperacetylation of IDH2 and SOD2 mitochondrial proteins, lowered enzymatic activities, and higher ROS levels. Overexpression of SIRT3 decreased proliferation and diminished the Warburg-like phenotype in SIRT3-deficient cell lines, and this effect is largely dependent on deacetylation of IDH2 and SOD2. Lastly, depletion of SIRT3 from malignant B cell lines resulted in greater susceptibility to treatment with an ROS scavenger but did not result in greater sensitivity to inhibition of the hypoxia-inducible factor-1␣ pathway, suggesting that loss of SIRT3 increases proliferation via ROS-dependent but hypoxiainducible factor-1␣-independent mechanisms. Our study suggests that SIRT3 acts as a tumor suppressor in B cell malignancies, and activating the SIRT3 pathway might represent a novel therapeutic approach for treating B cell malignancies.

Integrative Biology, 2015

We have developed a microfluidicscis-coculture assay platform to identify myeloma patient respons... more We have developed a microfluidicscis-coculture assay platform to identify myeloma patient responsesex vivo.

$Research paper thumbnail of Tumoricidal Effects of Macrophage-activating Immunotherapy in a Murine Model of Relapsed/ Refractory Multiple Myeloma$

Cancer immunology research, Jan 4, 2015

Myeloma remains a virtually incurable malignancy. The inevitable evolution of multi-drug resistan... more Myeloma remains a virtually incurable malignancy. The inevitable evolution of multi-drug resistant clones and widespread clonal heterogeneity limit the potential of traditional and novel therapies to eliminate minimal residual disease, a reliable harbinger of relapse. Here we show potent anti-myeloma activity of macrophage-activating immunotherapy (αCD40+CpG) that resulted in prolongation of progression-free and overall survival in an immunocompetent, preclinically validated, transplant-based model of multi-drug resistant, relapsed/refractory myeloma (t-Vκ*MYC). αCD40+CpG was effective in vivo in the absence of cytolytic NK, T or B cells and resulted in expansion of M1-polarized (cytolytic/tumoricidal) macrophages in the bone marrow. Moreover, we show that concurrent loss/inhibition of TPL2 (Cot, MAP3K8), a MAP3K that is recruited to activated CD40 complex and regulates macrophage activation/cytokine production, potentiated direct, ex vivo anti-myeloma tumoricidal activity of αCD40+...

Proceedings of the National Academy of Sciences of the United States of America, Jan 8, 2015

Multiple myeloma (MM), a malignancy of plasma cells, is characterized by widespread genomic heter... more Multiple myeloma (MM), a malignancy of plasma cells, is characterized by widespread genomic heterogeneity and, consequently, differences in disease progression and drug response. Although recent large-scale sequencing studies have greatly improved our understanding of MM genomes, our knowledge about genomic structural variation in MM is attenuated due to the limitations of commonly used sequencing approaches. In this study, we present the application of optical mapping, a single-molecule, whole-genome analysis system, to discover new structural variants in a primary MM genome. Through our analysis, we have identified and characterized widespread structural variation in this tumor genome. Additionally, we describe our efforts toward comprehensive characterization of genome structure and variation by integrating our findings from optical mapping with those from DNA sequencing-based genomic analysis. Finally, by studying this MM genome at two time points during tumor progression, we ha...

Cancer Research, 2014

Early-stage myeloma tumor cells are critically dependent on paracrine cytokine support originatin... more Early-stage myeloma tumor cells are critically dependent on paracrine cytokine support originating from their bone marrow microenvironment whereas advanced-stage myeloma tumor cells may elaborate autocrine cytokine production mechanisms and/or cell-autonomous mutations in critical downstream signaling pathways (e.g., NFκB pathway). However, the molecular mechanisms underpinning the paracrine network in myeloma are unclear. The pro-inflammatory cytokine IL-1β has emerged as a major link between inflammation and cancer and has been validated as a therapeutic target in high-risk monoclonal gammopathy, the precursor to myeloma, as well as early-stage myeloma. To determine the source of IL-1β production in early-stage myeloma we analyzed paired purified cell fractions obtained from each of 5 patients at diagnosis: CD138+ tumor cells, CD14+ bone marrow-resident monocyte/macrophages as well as bone marrow-derived stromal/mesenchymal cells (BM-MSC). We found that in all cases, monocytes/mac...

$Research paper thumbnail of Acetyl-l-carnitine (ALCAR) for the prevention of chemotherapy-induced peripheral neuropathy in patients with relapsed or refractory multiple myeloma treated with bortezomib, doxorubicin and low-dose dexamethasone: a study from the Wisconsin Oncology Network$

Cancer Chemotherapy and Pharmacology, 2014

PN was 32 % in the BDD group versus 15 % in the BDD-A group (p = ns). Patient-reported fatigue an... more PN was 32 % in the BDD group versus 15 % in the BDD-A group (p = ns). Patient-reported fatigue and PN measured by FACT-GOG-TX increased throughout the treatment period in the BDD-A group, although time to complete GP testing declined. In a sub-study examining constitutive bortezomib-inducible NF-κB activity in primary subjectspecific MM cells, the presence of NF-κB activation correlated with lower likelihood of response. Conclusions Addition of ALCAR to BDD did not alter the incidence or severity of PN in relapsed MM patients receiving a B-based regimen. Bortezomib-inducible NF-κB activation in patient-derived primary MM cells may be associated with poorer response. Keywords Multiple myeloma • Bortezomib • Neuropathy • Acetyl-l-carnitine • NF-kB [2]. Initial trials of single agent bortezomib for relapsed MM resulted in response rates of 30-35 % [3, 4]. However, MM patients rapidly acquire resistance to bortezomib when used as a single agent, and it is apparent that this resistance may in part be modified through combination with other existing chemotherapy agents, including steroids,