3400 Spruce Street 5 Silverstein Bldg
Philadelphia PA 19104
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CD38-Expressing Myeloid-Derived Suppressor Cells Promote Tumor Growth in a Murine Model of Esophageal Cancer. - Cancer research
Myeloid-derived suppressor cells (MDSC) are an immunosuppressive population of immature myeloid cells found in advanced-stage cancer patients and mouse tumor models. Production of inducible nitric oxide synthase (iNOS) and arginase, as well as other suppressive mechanisms, allows MDSCs to suppress T-cell-mediated tumor clearance and foster tumor progression. Using an unbiased global gene expression approach in conditional p120-catenin knockout mice (L2-cre;p120ctn(f/f)), a model of oral-esophageal cancer, we have identified CD38 as playing a vital role in MDSC biology, previously unknown. CD38 belongs to the ADP-ribosyl cyclase family and possesses both ectoenzyme and receptor functions. It has been described to function in lymphoid and early myeloid cell differentiation, cell activation, and neutrophil chemotaxis. We find that CD38 expression in MDSCs is evident in other mouse tumor models of esophageal carcinogenesis, and CD38(high) MDSCs are more immature than MDSCs lacking CD38 expression, suggesting a potential role for CD38 in the maturation halt found in MDSC populations. CD38(high) MDSCs also possess a greater capacity to suppress activated T cells, and promote tumor growth to a greater degree than CD38(low) MDSCs, likely as a result of increased iNOS production. In addition, we have identified novel tumor-derived factors, specifically IL6, IGFBP3, and CXCL16, which induce CD38 expression by MDSCs ex vivo. Finally, we have detected an expansion of CD38(+) MDSCs in peripheral blood of advanced-stage cancer patients and validated targeting CD38 in vivo as a novel approach to cancer therapy. Cancer Res; 75(19); 4074-85. Â©2015 AACR.Â©2015 American Association for Cancer Research.
IGFBP3 promotes esophageal cancer growth by suppressing oxidative stress in hypoxic tumor microenvironment. - American journal of cancer research
Insulin-like growth factor binding protein 3 (IGFBP3), a hypoxia-inducible gene, regulates a variety of cellular processes including cell proliferation, senescence, apoptosis and epithelial-mesenchymal transition (EMT). IGFBP3 has been linked to the pathogenesis of cancers. Most previous studies focus upon proapoptotic tumor suppressor activities of IGFBP3. Nevertheless, IGFBP3 is overexpressed in certain cancers including esophageal squamous cell carcinoma (ESCC), one of the most aggressive forms of squamous cell carcinomas (SCCs). The tumor-promoting activities of IGFBP3 remain poorly understood in part due to a lack of understanding as to how the tumor microenvironment may influence IGFBP3 expression and how IGFBP3 may in turn influence heterogeneous intratumoral cell populations. Here, we show that IGFBP3 overexpression is associated with poor postsurgical prognosis in ESCC patients. In xenograft transplantation models with genetically engineered ESCC cells, IGFBP3 contributes to tumor progression with a concurrent induction of a subset of tumor cells showing high expression of CD44 (CD44H), a major cell surface receptor for hyaluronic acid, implicated in invasion, metastasis and drug resistance. Our gain-of-function and loss-of-function experiments reveal that IGFBP3 mediates the induction of intratumoral CD44H cells. IGFBP3 cooperates with hypoxia to mediate the induction of CD44H cells by suppressing reactive oxygen species (ROS) in an insulin-like growth factor-independent fashion. Thus, our study sheds light on the growth stimulatory functions of IGFPB3 in cancer, gaining a novel mechanistic insight into the functional interplay between the tumor microenvironment and IGFBP3.
Comparative secretome analysis of epithelial and mesenchymal subpopulations of head and neck squamous cell carcinoma identifies S100A4 as a potential therapeutic target. - Molecular & cellular proteomics : MCP
Epithelial-mesenchymal transition (EMT) is a key contributor in tumor progression and metastasis. EMT produces cellular heterogeneity within head and neck squamous cell carcinomas (HNSCC) by creating a phenotypically distinct mesenchymal subpopulation that is resistant to conventional therapies. In this study, we systematically characterized differences in the secretomes of E-cadherin high epithelial-like and E-cadherin low mesenchymal-like subpopulations using unbiased and targeted proteomics. A total 1765 proteins showed significant changes with 177 elevated in the epithelial subpopulation and 173 elevated in the mesenchymal cells. Key nodes in affected networks included NFÎºB, Akt, and ERK, and most implicated cellular components involved various aspects of the extracellular matrix. In particular, large changes were observed in multiple collagens with most affected collagens at much higher abundance levels in the mesenchymal subpopulation. These cells also exhibited a secretome profile resembling that of cancer-associated fibroblastic cells (CAF). S100A4, a commonly used marker for cancer-associated fibroblastic cells, was elevated more than 20-fold in the mesenchymal cells and this increase was further verified at the transcriptome level. S100A4 is a known mediator of EMT, leading to metastasis and EMT has been proposed as a potential source of cancer-associated fibroblastic cells in solid tumors. S100A4 knockdown by small interfering RNA led to decreased expression, secretion and activity of matrix metalloproteinase 2, as verified by quantitative PCR, multiple reaction monitoring and zymography analyses, and reduced invasion in collagen-embedded spheroids. Further confirmation in three-dimensional organotypic reconstructs showed less invasion and advanced differentiation in the S100A4 RNA interference samples. Orthotopic metastasis model, developed to validate the findings in vivo, demonstrated a decrease in spontaneous metastasis and augmented differentiation in the primary tumor in siS100A4 xenografts. These results demonstrate the value of secretome profiling to evaluate phenotypic conversion and identify potential novel therapeutic targets such as S100A4.
EGFR inhibition promotes an aggressive invasion pattern mediated by mesenchymal-like tumor cells within squamous cell carcinomas. - Molecular cancer therapeutics
Squamous cell carcinomas (SCC) with an infiltrative invasion pattern carry a higher risk of treatment failure. Such infiltrative invasion may be mediated by a mesenchymal-like subpopulation of malignant cells that we have previously shown to arise from epithelial-mesenchymal transition (EMT) and resist epidermal growth factor receptor (EGFR) targeting. Here, we show that SCCs with infiltrative, high-risk invasion patterns contain abundant mesenchymal-like cells, which are rare in tumors with low-risk patterns. This cellular heterogeneity was modeled accurately in three-dimensional culture using collagen-embedded SCC spheroids, which revealed distinct invasive fronts created by collective migration of E-cadherin-positive cells versus infiltrative migration of individual mesenchymal-like cells. Because EGFR expression by mesenchymal-like cells was diminished in the spheroid model and in human SCCs, we hypothesized that SCCs shift toward infiltrative invasion mediated by this subpopulation during anti-EGFR therapy. Anti-EGFR treatment of spheroids using erlotinib or cetuximab enhanced infiltrative invasion by targeting collective migration by E-cadherin-positive cells while sparing mesenchymal-like cells; by contrast, spheroid invasion in absence of mesenchymal-like cells was abrogated by erlotinib. Similarly, cetuximab treatment of xenografts containing mesenchymal-like cells created an infiltrative invasive front composed of this subpopulation, whereas no such shift was observed upon treating xenografts lacking these cells. These results implicate mesenchymal-like SCC cells as key mediators of the infiltrative invasion seen in tumors with locally aggressive behavior. They further show that EGFR inhibition can promote an infiltrative invasion front composed of mesenchymal-like cells preferentially in tumors where they are abundant before therapy.Â©2013 AACR.
Stem-like cells and therapy resistance in squamous cell carcinomas. - Advances in pharmacology (San Diego, Calif.)
Cancer stem cells (CSCs) within squamous cell carcinomas (SCCs) are hypothesized to contribute to chemotherapy and radiation resistance and represent potentially useful pharmacologic targets. Hallmarks of the stem cell phenotype that may contribute to therapy resistance of CSCs include quiescence, evasion of apoptosis, resistance to DNA damage, and expression of drug transporter pumps. A variety of CSC populations within SCCs of the head and neck and esophagus have been defined tentatively, based on diverse surface markers and functional assays. Stem-like self-renewal and differentiation capacities of these SCC subpopulations are supported by sphere formation and clonogenicity assays in vitro as well as limiting dilution studies in xenograft models. Early evidence supports a role for SCC CSCs in intrinsic therapy resistance, while detailed mechanisms by which these subpopulations evade treatment remain to be defined. Development of novel SCC therapies will be aided by pursuing such mechanisms as well as refining current definitions for CSCs and clarifying their relevance to hierarchical versus dynamic models of stemness.Copyright Â© 2012 Elsevier Inc. All rights reserved.
A NOTCH3-mediated squamous cell differentiation program limits expansion of EMT-competent cells that express the ZEB transcription factors. - Cancer research
Zinc finger E-box-binding (ZEB) proteins ZEB1 and ZEB2 are transcription factors essential in TGF-Î²-mediated senescence, epithelial-to-mesenchymal transition (EMT), and cancer stem cell functions. ZEBs are negatively regulated by members of the miR-200 microRNA family, but precisely how tumor cells expressing ZEBs emerge during invasive growth remains unknown. Here, we report that NOTCH3-mediated signaling prevents expansion of a unique subset of ZEB-expressing cells. ZEB expression was associated with the lack of cellular capability of undergoing NOTCH3-mediated squamous differentiation in human esophageal cells. Genetic inhibition of the Notch-mediated transcriptional activity by dominant-negative Mastermind-like 1 (DNMAML1) prevented squamous differentiation and induction of Notch target genes including NOTCH3. Moreover, DNMAML1-enriched EMT-competent cells exhibited robust upregulation of ZEBs, downregulation of the miR-200 family, and enhanced anchorage-independent growth and tumor formation in nude mice. RNA interference experiments suggested the involvement of ZEBs in anchorage-independent colony formation, invasion, and TGF-Î²-mediated EMT. Invasive growth and impaired squamous differentiation were recapitulated upon Notch inhibition by DNMAML1 in organotypic three-dimensional culture, a form of human tissue engineering. Together, our findings indicate that NOTCH3 is a key factor limiting the expansion of ZEB-expressing cells, providing novel mechanistic insights into the role of Notch signaling in the cell fate regulation and disease progression of esophageal squamous cancers.Â©2011 AACR.
Detecting and targeting mesenchymal-like subpopulations within squamous cell carcinomas. - Cell cycle (Georgetown, Tex.)
Curative eradication of all cells within carcinomas is seldom achievable with chemotherapy alone. This limitation may be partially attributable to tumor cell subpopulations with intrinsic resistance to current drugs. Within squamous cell carcinoma (SCC) cell lines, we previously characterized a subpopulation of mesenchymal-like cells displaying phenotypic plasticity and increased resistance to both cytotoxic and targeted agents. These mesenchymal-like (Ecad-lo) cells are separable from epithelial-like (Ecad-hi) cells based on loss of surface E-cadherin and expression of vimentin. Despite their long-term plasticity, both Ecad-lo and Ecad-hi subsets in short-term culture maintained nearly uniform phenotypes after purification. This stability allowed testing of segregated subpopulations for relative sensitivity to the cytotoxic agent cisplatin in comparison to salinomycin, a compound with reported activity against CD44(+)CD24(-) stem-like cells in breast carcinomas. Salinomycin showed comparable efficacy against both Ecad-hi and Ecad-lo cells in contrast to cisplatin, which selectively depleted Ecad-hi cells. An in vivo correlate of these mesenchymal-like Ecad-lo cells was identified by immunohistochemical detection of vimentin-positive malignant subsets across a part of direct tumor xenografts (DTXs) of advanced stage SCC patient samples. Cisplatin treatment of mice with established DTXs caused enrichment of vimentin-positive malignant cells in residual tumors, but salinomycin depleted the same subpopulation. These results demonstrate that mesenchymal-like SCC cells, which resist current chemotherapies, respond to a treatment strategy developed against a stem-like subset in breast carcinoma. Further, they provide evidence of mesenchymal-like subsets being well-represented across advanced stage SCCs, suggesting that intrinsic drug resistance in this subpopulation has high clinical relevance.
A temporarily distinct subpopulation of slow-cycling melanoma cells is required for continuous tumor growth. - Cell
Melanomas are highly heterogeneous tumors, but the biological significance of their different subpopulations is not clear. Using the H3K4 demethylase JARID1B (KDM5B/PLU-1/RBP2-H1) as a biomarker, we have characterized a small subpopulation of slow-cycling melanoma cells that cycle with doubling times of >4 weeks within the rapidly proliferating main population. Isolated JARID1B-positive melanoma cells give rise to a highly proliferative progeny. Knockdown of JARID1B leads to an initial acceleration of tumor growth followed by exhaustion which suggests that the JARID1B-positive subpopulation is essential for continuous tumor growth. Expression of JARID1B is dynamically regulated and does not follow a hierarchical cancer stem cell model because JARID1B-negative cells can become positive and even single melanoma cells irrespective of selection are tumorigenic. These results suggest a new understanding of melanoma heterogeneity with tumor maintenance as a dynamic process mediated by a temporarily distinct subpopulation.Copyright (c) 2010 Elsevier Inc. All rights reserved.
Warthin tumor presenting as a fungal abscess in an immunocompetent host: case report and review of the literature. - Head & neck
Fungal abscesses of the parotid gland are rare, and cases arising within parotid neoplasms have not been described previously. This report conveys our experience managing such an entity, which is further distinguished by its occurrence in an immunocompetent host.A 59-year-old man experienced multiple recurrences of a parotid fungal abscess requiring repeated drainage procedures. Definitive excision ultimately demonstrated Candida glabrata infecting a Warthin tumor.This case is the first report of a parotid neoplasm presenting as a fungal abscess. It contributes to the scant literature on fungal abscesses of the parotid, which previously has only been described in debilitated hosts and without an associated neoplasm. The case also expands the spectrum of disease associated with C. glabrata. Warthin tumor may be an occult etiology for a parotid fungal abscess, and definitive diagnosis and therapy may require parotidectomy.
Detection of occult bone metastases from head and neck squamous cell carcinoma: impact of positron emission tomography computed tomography with fluorodeoxyglucose F 18. - Archives of otolaryngology--head & neck surgery
To assess the ability of positron emission tomography-computed tomography with fluorodeoxyglucose F 18 (FDG-PET/CT) to provide early, accurate detection of bone metastases from head and neck squamous cell carcinoma (HNSCC) and to determine the impact of detecting occult bone metastases on patient care.Retrospective medical chart review.Single academic medical center.The study population comprised 13 patients with FDG-PET/CT scans detecting bone lesions suggestive of HNSCC metastases. These patients were identified from a retrospective review of 683 consecutive FDG-PET/CT scans performed for initial staging (n = 198) or restaging (n = 485) of HNSCC between October 2002 and December 2005.Rate of biopsy confirmation of bone lesions detected by FDG-PET/CT as suggestive of metastases, presence of concurrent symptoms or laboratory serologic evidence for bone metastasis, timing of bone metastasis detection relative to initial diagnosis of HNSCC, and change in therapeutic decision making based on bone metastasis detection.Eleven FDG-PET/CT studies that detected bone metastasis were performed to restage a suspected or known recurrence, and 2 studies were performed for radiographic restaging of disease after completion of therapy. Bone biopsy confirmation was performed in 5 patients, and 4 of the biopsy results were positive for metastatic HNSCC. All patients lacked clinical symptoms of bone involvement, and 82% (n = 9) had serum alkaline phosphatase levels in the normal (n = 7) or minimally elevated (n = 2) range. At the time of bone metastasis detection, 6 of the 12 patients (50%) had no other identifiable distant metastatic disease. Furthermore, 2 patients (17%) lacked disease at any other local, regional, or distant site. The identification of bone metastases influenced therapeutic decisions in 5 of 13 cases (38%).Use of FDG-PET/CT in restaging HNSCC allows for detection of occult bone metastases, and this early detection frequently influences therapeutic decision making.
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34Th & Civic Ctr Blvd Children's Hospital Of Philadelphia
3400 Spruce St 1 Maloney Building