Mediate Tumor Progression Research Articles

Regular Physical Activity Can Prevent the Oncogenic Effects of Lifestyle-Associated Advanced Glycation End Products

Abstract Objectives Lifestyle factors such as a sedentary lifestyle, obesity and a diet consisting of foods high in protein, fat, and highly processed foods contribute to the accumulation of advanced glycation end products (AGEs). AGE pathogenic effects are mediated through modification of protein function, genetic fidelity, stress responses, and cellular signaling pathways which can promote the development of a variety of chronic diseases. However, a gap in the literature exists on the role of dietary AGE in cancer progression and the potential impact of physical activity (PA) to negate such effects. Given the links between lifestyle and AGEs, we propose that a diet high in AGEs can accelerate prostate cancer progression and can be reversed by PA. Methods Xenograft and spontaneous prostate cancer mouse models were utilized to assess the effects of dietary AGE on prostate tumor growth. Mice were exposed to PA on an Animal Treadmill for 1 hr, 5 days a week to assess the impact on dietary AGE mediated tumor progression. Tumor and prostate tissue were collected for histology, and Western Blot analysis. PBMCs were isolated from endpoint blood draws for flow cytometric analysis. Results We found that chronic consumption of AGEs leads to a 3-fold increase in tumor growth in xenograft mice, accompanied by decreased expression of AR, increased expression of MYC, RAGE, and AGE as well as cell proliferation. In the spontaneous prostate cancer model chronic consumption of AGE resulted in increased progression towards high grade PIN and carcinoma when compared to l mice. IHC showed that the high AGE fed mice had increased recruitment of macrophages to PIN lesions. Mice in the PA arm showed a decrease in tumor growth (xenograft) and delayed progression (spontaneous). This was observed in all diet groups, but was most significant in the dietary AGE mice. Conclusions Our studies support the concept that AGEs represent a biological consequence of lifestyle factors that promote cancer progression, and that PA may alleviate these effects. This may have the greatest impact in African American populations who have worse outcomes in prostate cancer, and where a lack of PA, poor diet, and high obesity rates are more prevalent. Funding Sources Bradley Krisanits was supported by Hollings Cancer Center Pre-Doctoral Fellowship (MUSC), Graduate Assistance in Areas of National Need (US Dept. of Ed.), and U54 CA21096.

The aegis: platelets as biomarkers of tumor progression.

There is increasing awareness that platelets play a significant role in creating a hypercoagulable environment that mediates tumor progression, beyond their classical hemostatic function. Platelets have heterogenic responses to agonists, and differential release and uptake of bioactive molecules may be manipulated via reciprocal cross-talk with cells of the tumor microenvironment. Platelets thus promote tumor progression by enhancing tumor growth, promoting the development of tumor-associated vasculature and encouraging invasion. In the metastatic process, platelets form the shield that protects tumor cells from high-velocity forces and immunosurveillance, while ensuring the establishment of the pre-metastatic niche. This review presents the complexity of these concepts, considering platelets as biomarkers for diagnosis, prognosis and potentially as therapeutic targets in cancer.

Abstract B52: KRAS-IRF2 axis drives immune suppression and immune therapy resistance in colorectal cancer

Abstract The precise biologic functions and mechanisms of oncogenic KrasG12D (Kras*) in therapeutic resistance, including immune therapy, are not understood. Here, utilizing a colorectal cancer (CRC) mouse model engineered with an inducible Kras* transgene and conditional null APC and Trp53 alleles (iKAP) that we recently established (Boutin et al., Gene & Development 2017), we observed that KRAS*-expressing invasive tumors possess a prominent immune-suppressive profile characterized by a preponderance of myeloid-derived suppressor cells (MDSCs). Integrated transcriptomic and genomic analyses identified the Interferon Regulatory Factor 2 (IRF2) gene as a key downstream target of KRAS* mediating tumor progression and immune suppression. Mechanistically, integrated transcriptomics, cytokine profiling and ChIP-seq analysis identified CXCL3 as a key direct target of IRF2, and pharmacologic inhibition of CXCL3 or its receptor CXCR2 resulted in suppression of MDSC migration and infiltration in KRAS*-expressing CRC tumors. Translational studies established that de novo anti-PD1 resistance of KRAS*-expressing tumors can be overcome by enforced IRF2 expression or by treatment with small-molecule CXCR2 antagonist SX-682. Correspondingly, CRC patient tumors with higher IRF2 expression show increased response to anti-PD1 therapy. This KRAS*-mediated immune suppressive mechanism provides a framework for patient selection and combination therapies to enhance the effectiveness of immune checkpoint blockade therapy in advanced CRC. Citation Format: Wenting Liao, Michael Overman, Adam Boutin, Scott Kopetz, Ron DePinho, Alan Wang. KRAS-IRF2 axis drives immune suppression and immune therapy resistance in colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B52.

Porphyromonas gingivalis Promotes Oral Squamous Cell Carcinoma Progression in an Immune Microenvironment

Increasing evidence has revealed a significant association between microorganisms and oral squamous cell carcinoma (OSCC). Porphyromonas gingivalis, the keystone pathogen in chronic periodontitis, is considered an important potential etiologic agent of OSCC, but the underlying immune mechanisms through which P. gingivalis mediates tumor progression of the oral cancer remain poorly understood. Our cohort study showed that the localization of P. gingivalis in tumor tissues was related to poor survival of patients with OSCC. Moreover, P. gingivalis infection increased oral lesion multiplicity and size and promoted tumor progression in a 4-nitroquinoline-1 oxide (4NQO)–induced carcinogenesis mouse model by invading the oral lesions. In addition, CD11b+ myeloid cells and myeloid-derived suppressor cells (MDSCs) showed increased infiltration of oral lesions. Furthermore, in vitro observations showed that MDSCs accumulated when human-derived dysplastic oral keratinocytes (DOKs) were exposed to P. gingivalis, and CXCL2, CCL2, interleukin (IL)–6, and IL-8 may be potential candidate genes that facilitate the recruitment of MDSCs. Taken together, our findings suggest that P. gingivalis promotes tumor progression by generating a cancer-promoting microenvironment, indicating a close relationship among P. gingivalis, tumor progression of the oral cancer, and immune responses.

TRAF6 Activates Fibroblasts to Cancer-Associated Fibroblasts through FGF19 in Tumor Microenvironment to Benefit the Malignant Phenotype of Melanoma Cells

Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment and mediate tumor progression in various cancers. A previous study demonstrated that TRAF6 promotes the malignant phenotype of melanoma cells. However, the role of TRAF6 in melanoma CAFs remains unclear. In this study, we found that TRAF6 was significantly upregulated in CAFs adjacent to melanoma cells. Functional assays showed that TRAF6 promoted fibroblast proliferation and migration as well as MMP and α-SMA expression. Moreover, the expression of TRAF6 in fibroblasts promoted the malignant phenotype of melanoma cells invitro and invivo. Meanwhile, the intervention of TRAF6 expression in melanoma cells affected the activation of CAFs. We found that FGF19 was a key cytokine regulated by TRAF6 through NF-κB1 using luciferase assay and chromatin immunoprecipitation in melanoma cells. Because plasma FGF19 levels are elevated in patients with melanoma, it may significantly induce fibroblast activation invitro and invivo. Taken together, our results support that TRAF6 is a key molecule that mediates the interaction between melanoma cells and stromal fibroblasts, suggesting that TRAF6 is a potentially promising target in melanoma therapy.

A Review of the Literature on Metastatic Spine Disease

Metastatic spine disease is increasing in incidence and is a major cause for patient morbidity and mortality. The clinical presentation is often characterised by pain and spinal deformity and often progresses to neurological deficits without treatment. The cornerstones of treatment have been chemotherapy, radiation therapy and surgery to debulk and stabilize the spine. However, these are considered palliative procedures being limited by damage to normal healthy tissues. Recent studies have focused on the key pathways that mediate tumour progression and spread to bone and more targeted therapies that may reduce the injury to normal cells. This article reviews the key features, clinical presentation, workup and treatment options of spinal metastases.

Abstract PR08: Intratumoral T-cell distribution in murine and patient pancreatic cancer correlates with tissue heterogeneity and survival

Abstract The complex microenvironment characteristic of pancreatic ductal adenocarcinoma (PDAC) has been implicated as a critical mediator of tumor progression and therapeutic response. Spatial relationships of individual cellular and acellular components within tumors may offer novel insights into the dynamic and complex functions of PDAC. Using eight-color multiplex immunohistochemistry and novel spatial analysis algorithms, we report a heterogeneous and increased population of infiltrating T lymphocytes in the tumors compared to uninvolved pancreatic tissues of treatment-naïve PDAC patients. Spatial distribution of cytotoxic T cells in proximity to cancer cells independently correlates with increased overall patient survival. Collagen-I and aSMA-positive fibroblasts do not correlate with a paucity of T-cell accumulation around cancer cells, suggesting that PDAC desmoplasia may not be a simple physical barrier. However, T-cell infiltration was reduced in proximity to specific cancer cell subpopulations, supporting cancer-cell intrinsic mechanisms for immune avoidance. Further expansion of this technology using early and late primary tumors and metastatic tissue of genetically engineered mouse models (KrasLSL-G12D; p53R172H; PDX1-Cre; EYFPLSL) demonstrates similar T-cell heterogeneity and spatial associations. These data support the validity of multiplex and spatial analysis platforms for exploring the structure-function relationships in the PDAC microenvironment and suggest differential spatial relationships between cancer subtypes and the surrounding microenvironment may be a determining factor in PDAC progression. This abstract is also being presented as Poster A04. Citation Format: Julienne L. Carstens, Pedro Correa de Sampaio, Soutik Barua, Huamin Wang, Jared K. Burks, Arvind Rao, Valerie S. LeBleu, Raghu Kalluri. Intratumoral T-cell distribution in murine and patient pancreatic cancer correlates with tissue heterogeneity and survival [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr PR08.

Exploiting Current Understanding of Hypoxia Mediated Tumour Progression for Nanotherapeutic Development.

Hypoxia is one of the most common phenotypes of malignant tumours. Hypoxia leads to the increased activity of hypoxia-inducible factors (HIFs), which regulate the expression of genes controlling a raft of pro-tumour phenotypes. These include maintenance of the cancer stem cell compartment, epithelial-mesenchymal transition (EMT), angiogenesis, immunosuppression, and metabolic reprogramming. Hypoxia can also contribute to the tumour progression in a HIF-independent manner via the activation of a complex signalling network pathway, including JAK-STAT, RhoA/ROCK, NF-κB and PI3/AKT. Recent studies suggest that nanotherapeutics offer a unique opportunity to target the hypoxic microenvironment, enhancing the therapeutic window of conventional therapeutics. In this review, we summarise recent advances in understanding the impact of hypoxia on tumour progression, while outlining possible nanotherapeutic approaches for overcoming hypoxia-mediated resistance.

MicroRNA Regulates Estrogen Receptor Alpha in Breast Cancer Metastasis

Breast cancer (BCa) is a common endocrine disorder among postmenopausal women and estradiol (E2) known causative agent for metastasis. During previous decade, tiny microRNAs (miRNAs) become a potential mediator of tumor suppressor or tumorigenic factor. Numerous miRNA regulates nuclear receptor ERα under the influence of estradiol (E2) such as miR101, miR-21 whereas miR145, miR-29a, miR-206, let-7 potentiates ERα proliferating activity. MiR-221/222 have established in hormone refractory condition after long exposure of Selective Estrogen Receptor Modulators (SERMs) or Selective Estrogen Receptor Down Regulator (SERDs). The target genes and the role of miRNAs in ERα mediated tumor progression is a challenging area of research that will open new clinical values as novel biomarkers in diagnosis and therapy.

Prognostic significance of tumour-infiltrating lymphocytes on survival outcomes of patients with resected pancreatic ductal adenocarcinoma: A systematic review and meta-analysis

Abstract Background Pancreatic cancer remains a leading cause of cancer-related mortality worldwide. Tumor-infiltrating lymphocytes (TILs) play an important role in mediating tumor progression and treatment resistance in pancreatic cancer. However, the prognostic value of TILs in pancreatic cancer remains uncertain. This meta-analysis evaluated the prognostic significance of TIL subsets (CD3+, CD4+, CD8+, FoxP3+ T cells) on overall survival (OS) and disease-free survival (DFS) of patients with resected pancreatic ductal adenocarcinoma. Methods Pertinent studies were gathered through systematic search of PubMed, Google Scholar and Cochrane Library databases up to August 1, 2019. Using Review Manager version 5.3, pooled hazard ratios and 95% confidence intervals were calculated using random or fixed effects models, depending on the heterogeneity of studies. Results A total of 11 studies comprising 1760 patients were included. Pooled analysis revealed that high levels of CD8+ TILs were associated with improved OS (HR = 0.59, 95% CI = 0.51-0.69, p Conclusion TILs are a promising prognostic biomarker in pancreatic cancer. High levels of CD8+ TILs correlated with favorable OS and DFS, while high levels of FoxP3+ TILs associated with poor OS. Nonetheless, results of this meta-analysis should be approached with caution due to the lack of established standards in assessment of TILs and the small number of available studies. Prospective studies that assess TILs in a more comprehensive and standardized manner are needed. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Endocan Expression Profile in Different Grades of Oral Squamous Cell Carcinoma

Background: Oral cancer is one of the most prevalent malignancies and presents increasing incidence and mortality trends in the world, with a mortality rate of 14.33. Oral squamous cell carcinoma (OSCC) constitutes 90 of all malignancies in the oral cavity. In spite of new therapeutic strategies, the risk of metastasis and mortality rate is still very high. Methods: A total of 54 samples (18 samples of each grade) were collected from the archives of the Pathology Department of Be’sat Educational Hospital, Hamadan, Iran from 2000 to 2017. The specimens were processed for immunohistochemistry (IHC) analysis. Besides, the samples were stained with Periodic Acid-Schiff (PAS) method for vasculogenic mimicry (VM) detection. Results: The chi-square test showed statistically significant differences between the expression level of endocan and lesion grade in the research groups (P = 0.025), lesion grade and VM formation (P = 0.001), and tumor grade and microvessel density (MVD) count (P = 0.000). Conclusions: The results suggest that endocan mediates tumor progression possibly via a few mechanisms such as cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), and VM formation. Further studies are required to reveal the mechanisms, by which the endocan acts as an oncogene. In addition, endocan could be considered as one of the tumor markers and a possible new target for cancer therapy. © 2019, Author(s).

CCAAT/enhancer-binding protein delta regulates the stemness of glioma stem-like cells through activating PDGFA expression upon inflammatory stimulation

BackgroundThe small population of glioma stem-like cells (GSCs) contributes to tumor initiation, malignancy, and recurrence in glioblastoma. However, the maintenance of GSC properties in the tumor microenvironment remains unclear. In glioma, non-neoplastic cells create an inflammatory environment and subsequently mediate tumor progression and maintenance. Transcriptional factor CCAAT/enhancer-binding protein delta (CEBPD) is suggested to regulate various genes responsive to inflammatory cytokines, thus prompting us to investigate its role in regulating GSCs stemness after inflammatory stimulation.MethodsStemness properties were analyzed by using spheroid formation. Oncomine and TCGA bioinformatic databases were used to analyze gene expression. Western blotting, quantitative real-time polymerase chain reaction, luciferase reporter assay, and chromatin immunoprecipitation assay were used to analyze proteins and gene transcript levels. The glioma tissue microarrays were used for CEBPD and PDGFA expression by immunohistochemistry staining.ResultsWe first found that IL-1β promotes glioma spheroid formation and is associated with elevated CEBPD expression. Using microarray analysis, platelet-derived growth factor subunit A (PDGFA) was confirmed as a CEBPD-regulated gene that mediates IL-1β-enhanced GSCs self-renewal. Further analysis of the genomic database and tissue array revealed that the expression levels between CEBPD and PDGFA were coincident in glioma patient samples.ConclusionThis is the first report showing the activation of PDGFA expression by CEBPD through IL-1β treatment and a novel CEBPD function in maintaining the self-renewal feature of GSCs.

Abstract 111: Tumor microenvironment derived NRG1 promotes antiandrogen resistance in prostate cancer

Abstract Despite the improved clinical outcomes for patients with advanced prostate cancer due to the use of second generation antiandrogens, acquired drug resistance inevitably occurs and remains the major challenge for prostate cancer therapy. While several cell-autonomous mechanisms of drug resistance have been elucidated previously, for a large number of patients the mechanism of resistance remains unclear. Recent studies point to the importance of the tumor microenvironment (TME), and cancer associated fibroblasts (CAF) in the TME, in mediating tumor progression and resistance to therapy, but whether CAFs specifically contribute to antiandrogen resistance in prostate cancer is not known. Using a preclinical model that faithfully mimics the typical progression of patients on antiandrogen therapy, we found that antiandrogen resistance develops significantly faster when cells are grown in the presence of their cognate CAFs. By carrying out biochemical purification and mass spectrometry analysis, we identified NRG1 as a CAF secreted factor, and found that it can promote antiandrogen resistance in tumor cells, via activation of HER3 in the tumor. Importantly, blocking either NRG1 or HER3 can re-sensitize tumors to antiandrogen treatment in this model. Moreover, NRG1 expression is up-regulated in CAFs after antiandrogen exposure or in androgen deprivation condition. Clinically, increased stroma-NRG1 expression was observed in patients post androgen deprivation therapy but not in hormonally intact men. Taken together, this work has revealed a novel, NRG1-mediated non-cell autonomous mechanism of antiandrogen resistance in prostate cancer, and suggests that therapeutically targeting NRG1 in the setting of metastatic, antiandrogen-resistant prostate cancer with elevated NRG1 could provide significant benefit to patients. Note: This abstract was not presented at the meeting. Citation Format: Zeda Zhang, Wouter Karthaus, Jose Mauricio Mota, Ping Mu, Chao Wu, Wassim Abida, Eliot Linton, Young Sun Lee, Eugine Lee, Ninghui Mao, Elizabeth Adams, Danielle Choi, Dana E. Rathkopf, Brett Carver, Anuradha Gopalan, Xuejun Jiang, Philip Watson, Charles Sawyers. Tumor microenvironment derived NRG1 promotes antiandrogen resistance in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 111.

Abstract 1981: M2-macrophage derived exosomes mediates tumor progression via GATA3-IL-4-IL-13 axis in ovarian cancer

Abstract Tumor microenvironment is the key factor for tumor progression. Stromal cells which consist of, tumor associated macrophages(TAMs), tumor associated fibroblast as well as cancer stem cells has been implicated in the acquisition of oncogenic phenotype via cell-cell communication. Exosomes are the major players in tumor microenvironment that contributes to tumorigenesis. Exosomes carry genetic information from host cells to another cell to reprogram the recipient cell. Exosomes from TAMS has emerged as important mediators of tumor growth. Here, we report that GATA3 is released abundantly from TAM cells via exosomes and promote oncogenesis. GATA3 acts as an oncogenic protein and silencing GATA3 by siRNA led to decrease in tumor cell viability. Our data showed that silencing GATA3 increased the release of IL-4 and IL-13 from EOC cells, which leads to M2 cell polarization from M0 cells. Our results suggest that GATA3 released from macrophage exosomes contributes to tumor growth by affecting intracellular processes as well as tumor microenvironment. P.K. and A. El-A. contributed equally. Citation Format: Pinar Kanlikilicer, Amr Ahmed El-Arabey, Merve Denizli, Recep Bayraktar, Bulent Ozpolat, Gabriel Lopez-Berestein, Salama Abdu Salama, Adel Rashad Abd-Allah. M2-macrophage derived exosomes mediates tumor progression via GATA3-IL-4-IL-13 axis in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1981.

Abstract 5154: Developing Micro-fluidic Chip to understand Altruistic stem cell reprogramming

Abstract Background:Tumor microenvironment (TME) is a complex network of cancer and stromal cell interactions in specialized niches. Cancer stem cells (CSCs) and mesenchymal stem cells (MSCs) co-exist as significant components of TME that contribute to tumor progression. However, it is not clear whether MSCs compete or co-operate with CSCs for niche occupancy. In principle, stem cell competition eliminates the competing neighbors (e.g. p53 mutant cancer cells) while stem cell altruism enhances group-fitness in the niche. We found that the conditioned media of oral cancer CSCs, ABCG2+ cells, induced stem cell altruism in CD271+ MSCs (1). This indirect demonstration suggests the potential role of stem cell altruism in TME mediated tumor progression. Here we hypothesize that CSC mediated stem cell altruism of MSCs can be studied using an organ-on-chip microfluidic device. Methods:Naïve CD271+ MSCs were maintained in vitro by using an established culture method that we previously reported (2). Development of organ-on-chip microfluidic platform involved coating of 96 wells with polydimethylsiloxane (PDMS) and squalene to enhance cellular adhesion and delay stem cell differentiation. Two wells were linked by microfluidic channels to facilitate cell-to-cell interaction. We used 1000 ABCG2+ CSCs obtained from SCC-25 cell line (3) and equal numbers of naïve CD271+ MSCs. CSCs co-cultured with MSC in a Boyden-chamber assay was used as control population. After two weeks of culture, MSCs were evaluated for potential reprogramming to altruistic stem cell (ASC) phenotype as previously described. Results:We observed that MSCs collected from organ-on-chip exhibit stem cell altruism as indicated by loss of p53 and gain of HIF-2alpha expression as measured by In-Cell western assay (1). These MSCs also exhibited secretion of GSH, another characteristic of ASCs. Subsequently, these cells activated p53/MDM2 oscillation, and underwent apoptosis/differentiation, another important characteristic of ASCs. While, MSCs cultured in Boyden chamber assay, showed rapid proliferation and loss of CD271+ expression, and gain of markers associated with carcinoma-associated-fibroblasts including SMA and cytokeratin 8. Conclusion:Overall, our findings suggest that microfluidics-based organ-on-chip device can be used to understand stem cell altruism in TME. 1. PMID:22689594.2. PMID: 288841133. Talukdar J et al In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 920. Note: This abstract was not presented at the meeting. Citation Format: Bidisha Pal, Sorra Sandhya, Joyeeta Talukdar, Lekhika Pathak, Hong Li, Bikul Das. Developing Micro-fluidic Chip to understand Altruistic stem cell reprogramming [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5154.

UBE2S mediates tumor progression via SOX6/β-Catenin signaling in endometrial cancer.

Dysregulation of ubiquitin-conjugating enzyme E2S (UBE2S) contributes to tumor progression. However, its clinical significance and biological function in endometrial cancer (EMC) remain unclear. Here, we show that UBE2S is upregulated in EMC and exhibits oncogenic activities via activation of SOX6/β-Catenin signaling. High expression of UBE2S is significantly associated with poor prognosis in two independent cohorts consisting of a total of 773 patients with EMC. in vitro studies demonstrate that ectopic expression of UBE2S promotes cell proliferation and migration, whereas knockdown of UBE2S results in opposite phenotypes. Overexpression of UBE2S in EMC cells enhances the nuclear translocation of β-Catenin, and subsequently induces the expression of c-Myc and Cyclin D1. Inhibition of β-Catenin by XAV-939 markedly attenuates UBE2S-promoted cell growth. Mechanistically, UBE2S suppresses the expression of SOX6 to trigger β-Catenin signaling. Re-expression of SOX6 in UBE2S-expressing EMC cells abolishes the nuclear localization of β-Catenin. Collectively, these data suggest UBE2S may serve as a promising prognostic factor and function as an oncogene in EMC. The newly identified UBE2S/SOX6/β-Catenin axis represents a new potential therapeutic target for EMC intervention.

The cancer-related transcription factor RUNX2 modulates expression and secretion of the matricellular protein osteopontin in osteosarcoma cells to promote adhesion to endothelial pulmonary cells and lung metastasis.

Osteosarcomas are bone tumors that frequently metastasize to the lung. Aberrant expression of the transcription factor, runt-related transcription factor 2 (RUNX2), is a key pathological feature in osteosarcoma and associated with loss of p53 and miR-34 expression. Elevated RUNX2 may transcriptionally activate genes mediating tumor progression and metastasis, including the RUNX2 target gene osteopontin (OPN/SPP1). This gene encodes a secreted matricellular protein produced by osteoblasts to regulate bone matrix remodeling and tissue calcification. Here we investigated whether and how the RUNX2/OPN axis regulates lung metastasis of osteosarcoma. Importantly, RUNX2 depletion attenuates lung metastasis of osteosarcoma cells in vivo. Using next-generation RNA-sequencing, protein-based assays, as well as the loss- and gain-of-function approaches in selected osteosarcoma cell lines, we show that osteopontin messenger RNA levels closely correlate with RUNX2 expression and that RUNX2 controls the levels of secreted osteopontin. Elevated osteopontin levels promote heterotypic cell-cell adhesion of osteosarcoma cells to human pulmonary microvascular endothelial cells, but not in the presence of neutralizing antibodies. Collectively, these findings indicate that the RUNX2/OPN axis regulates the ability of osteosarcoma cells to attach to pulmonary endothelial cells as a key step in metastasis of osteosarcoma cells to the lung.

Lactate inhibits ATP6V0d2 expression in tumor-associated macrophages to promote HIF-2α-mediated tumor progression.

Macrophages perform key functions in tissue homeostasis that are influenced by the local tissue environment. Within the tumor microenvironment, tumor-associated macrophages can be altered to acquire properties that enhance tumor growth. Here, we found that lactate, a metabolite found in high concentration within the anaerobic tumor environment, activated mTORC1 that subsequently suppressed TFEB-mediated expression of the macrophage-specific vacuolar ATPase subunit ATP6V0d2. Atp6v0d2-/- mice were more susceptible to tumor growth, with enhanced HIF-2α-mediated VEGF production in macrophages that display a more protumoral phenotype. We found that ATP6V0d2 targeted HIF-2α but not HIF-1α for lysosome-mediated degradation. Blockade of HIF-2α transcriptional activity reversed the susceptibility of Atp6v0d2-/- mice to tumor development. Furthermore, in a cohort of patients with lung adenocarcinoma, expression of ATP6V0d2 and HIF-2α was positively and negatively correlated with survival, respectively, suggesting a critical role of the macrophage lactate/ATP6V0d2/HIF-2α axis in maintaining tumor growth in human patients. Together, our results highlight the ability of tumor cells to modify the function of tumor-infiltrating macrophages to optimize the microenvironment for tumor growth.

BAG3 contributes to HGF-mediated cell proliferation, migration, and invasion via the Egr1 pathway in gastric cancer.

Bcl2-associated athanogene 3 (BAG3) is elevated in several types of cancers. However, the role of BAG3 in progression of gastric cancer is unknown. Therefore, the present study aims to find out the role of BAG3 in hepatocyte growth factor (HGF)-mediated tumor progression and the molecular mechanisms by which HGF regulates BAG3 expression. BAG3 mRNA and protein were measured using reverse transcription polymerase chain reaction and Western blot in the 2 human gastric cancer cell lines, NUGC3 and MKN28, treated with or without HGF. The effects of BAG3 knockdown on cell proliferation, cell invasion, and apoptosis were analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the in vitro 2-chamber invasion assay, and flow cytometry in BAG3 short hairpin RNA (shRNA)-transfected cells and control cells. The signaling pathways involved in BAG3 that are regulated by HGF were analyzed. The chromatin immunoprecipitation assay was used to determine binding of Egr1 to the BAG3 promoter. BAG3 mRNA and protein levels were increased following treatment with HGF. HGF-mediated BAG3 upregulation increased cell proliferation and cell invasion; however, it decreased apoptosis. HGF-mediated BAG3 upregulation is regulated by an ERK and Egr1-dependent pathway. BAG3 may have an important role in HGF-mediated cell proliferation and metastasis in gastric cancer through an ERK and Egr1-dependent pathway. This pathway may provide novel therapeutic targets and provide information for further identification of other targets of therapeutic significance in gastric cancer.

Tumor-Induced Cholesterol Efflux from Macrophages Drives IL-4 Mediated Reprogramming and Tumor Progression

Tumor-associated macrophages (TAM) have been shown to have important roles in the malignant progression of various cancers. However, macrophages also posses intrinsic tumoricidal activity and can promote the activity of cytotoxic lymphocytes, but they rapidly adopt an alternative phenotype within tumors, associated with immune-suppression and trophic functions that support tumor growth. The mechanisms that promote TAM polarization in the tumor-microenvironment remain poorly understood, these mechanisms may represent important therapeutic targets to block the tumor-promoting functions of TAM and restore their anti-tumor potential. Here we have characterized TAM in a mouse model of metastatic ovarian cancer. We show that ovarian cancer cells promote membrane-cholesterol efflux and the depletion of lipid rafts from macrophages. Increased cholesterol efflux promoted IL-4 mediated reprogramming while inhibiting IFNγ-induced gene expression. These studies reveal an unexpected role for tumor-induced membrane-cholesterol efflux in driving the IL-4 signaling and the tumor-promoting functions of TAM, while rendering them refractory to pro-inflammatory stimuli. Thus, preventing cholesterol efflux in TAM could represent a novel therapeutic strategy to block pro-tumor functions and restore anti-tumor immunity.