Investigating the Role of SNAI1 and ZEB1 Expression in Prostate Cancer Progression and Immune Modulation of the Tumor Microenvironment.

Prostate cancer (PCa) is an immunologically cold tumor and the molecular processes that underlie this behavior are poorly understood. In this study, we investigated a primary cohort of intermediate-risk PCa (n = 51) using two NanoString profiling panels designed to study cancer progression and immune response. We identified differentially expressed genes (DEGs) and pathways associated with biochemical recurrence (BCR) and clinical risk. Confirmatory analysis was performed using the TCGA-PRAD cohort. Noteworthy DEGs included collagens such as COL1A1, COL1A2, and COL3A1. Changes in the distribution of collagens may influence the immune activity in the tumor microenvironment (TME). In addition, immune-related DEGs such as THY1, IRF5, and HLA-DRA were also identified. Enrichment analysis highlighted pathways such as those associated with angiogenesis, TGF-beta, UV response, and EMT. Among the 39 significant DEGs, 11 (28%) were identified as EMT target genes for ZEB1 using the Harmonizome database. Elevated ZEB1 expression correlated with reduced BCR risk. Immune landscape analysis revealed that ZEB1 was associated with increased immunosuppressive cell types in the TME, such as naïve B cells and M2 macrophages. Increased expression of both ZEB1 and SNAI1 was associated with elevated immune checkpoint expression. In the future, modulation of EMT could be beneficial for overcoming immunotherapy resistance in a cold tumor, such as PCa.

Epithelial-Mesenchymal Transition Signaling and Prostate Cancer Stem Cells: Emerging Biomarkers and Opportunities for Precision Therapeutics.

Prostate cancers may reactivate a latent embryonic program called the epithelial-mesenchymal transition (EMT) during the development of metastatic disease. Through EMT, tumors can develop a mesenchymal phenotype similar to cancer stem cell traits that contributes to metastasis and variation in therapeutic responses. Some of the recurrent somatic mutations of prostate cancer affect EMT driver genes and effector transcription factors that induce the chromatin- and androgen-dependent epigenetic alterations that characterize castrate-resistant prostate cancer (CRPC). EMT regulators in prostate cancer comprise transcription factors (SNAI1/2, ZEB1, TWIST1, and ETS), tumor suppressor genes (RB1, PTEN, and TP53), and post-transcriptional regulators (miRNAs) that under the selective pressures of antiandrogen therapy can develop an androgen-independent metastatic phenotype. In prostate cancer mouse models of EMT, Slug expression, as well as WNT/ß-Catenin and notch signaling pathways, have been shown to increase stemness potential. Recent single-cell transcriptomic studies also suggest that the stemness phenotype of advanced prostate cancer may be related to EMT. Other evidence correlates EMT and stemness with immune evasion, for example, activation of the polycomb repressor complex I, promoting EMT and stemness and cytokine secretion through RB1, TP53, and PRC1. These findings are helping clinical trials in CRPC that seek to understand how drugs and biomarkers related to the acquisition of EMT can improve drug response.

The Role of Somatic Mutations on the Immune Response of the Tumor Microenvironment in Prostate Cancer.

Immunotherapy has improved patient survival in many types of cancer, but for prostate cancer, initial results with immunotherapy have been disappointing. Prostate cancer is considered an immunologically excluded or cold tumor, unable to generate an effective T-cell response against cancer cells. However, a small but significant percentage of patients do respond to immunotherapy, suggesting that some specific molecular subtypes of this tumor may have a better response to checkpoint inhibitors. Recent findings suggest that, in addition to their function as cancer genes, somatic mutations of PTEN, TP53, RB1, CDK12, and DNA repair, or specific activation of regulatory pathways, such as ETS or MYC, may also facilitate immune evasion of the host response against cancer. This review presents an update of recent discoveries about the role that the common somatic mutations can play in changing the tumor microenvironment and immune response against prostate cancer. We describe how detailed molecular genetic analyses of the tumor microenvironment of prostate cancer using mouse models and human tumors are providing new insights into the cell types and pathways mediating immune responses. These analyses are helping researchers to design drug combinations that are more likely to target the molecular and immunological pathways that underlie treatment failure.

Emerging role of PTEN loss in evasion of the immune response to tumours.

Mutations in PTEN activate the phosphoinositide 3-kinase (PI3K) signalling network, leading to many of the characteristic phenotypic changes of cancer. However, the primary effects of this gene on oncogenesis through control of the PI3K-AKT-mammalian target of rapamycin (mTOR) pathway might not be the only avenue by which PTEN affects tumour progression. PTEN has been shown to regulate the antiviral interferon network and thus alter how cancer cells communicate with and are targeted by immune cells. An active, T cell-infiltrated microenvironment is critical for immunotherapy success, which is also influenced by mutations in DNA damage repair pathways and the overall mutational burden of the tumour. As PTEN has a role in the maintenance of genomic integrity, it is likely that a loss of PTEN affects the immune response at two different levels and might therefore be instrumental in mediating failed responses to immunotherapy. In this review, we summarise findings that demonstrate how the loss of PTEN function elicits specific changes in the immune response in several types of cancer. We also discuss ongoing clinical trials that illustrate the potential utility of PTEN as a predictive biomarker for immune checkpoint blockade therapies.

Envolvimento das galectinas na angiogênese tumoral em modelo de melanoma murino e associação com o microambiente tumoral via receptores toll-like / Involvement of galectins in tumor angiogenesis in a murine melanoma model and association with tumor microenvironment through toll-like receptors

O melanoma é a forma mais letal entre os cânceres de pele. Essa neoplasia freqüentemente apresenta-se resistente a abordagens terapêuticas. A angiogênese associada ao tumor representa um crítico passo da tumorigênese, resultado da ação de diferentes citocinas e fatores de crescimento como VEGF produzidos no microambiente tumoral. As galectinas extracelulares participam de múltiplos processos biológicos incluindo angiogênese tumoral e metástases, sua interação com as células presentes no microambiente tumoral pode ocorrer via receptores toll-like sugerindo seu envolvimento nos processos pro-inflamatórios e na secreção de citocinas. Recentemente mostramos que a ausência de gal-3 no estroma e parênquima tumoral diminui a angiogênese por interferir na resposta de macrófagos via VEGF e/ou TGFbeta1. Entretanto, o envolvimento de galectinas extracelulares na angiogênese e na modulação do sistema imune no microambiente tumoral ainda não está esclarecido. Assim, este estudo visa buscar respostas ao envolvimento das galectinas no crescimento tumoral e angiogênese contribuindo ao combate do melanoma maligno. Nossos resultados mostram a participação das galectinas 1 e 3 no crescimento tumoral e seu envolvimento com macrófagos via receptores toll-like, além de coordenarem a modulação do perfil de polarização de macrófagos derivados da medula óssea de camundongos wild-type. Dessa forma, podemos inferir que essas galectinas agem como coordenadoras de mudança de perfil dos macrófagos, uma vez que inibidas extracelularmente promovem uma diminuição do crescimento tumoral em camundongos wild-type, inoculados com células de melanoma murino e uma manutenção do perfil de macrófagos M1 in vitro. Assim, concluimos que as galectinas 1 e 3 extracelulares são importantes para o crescimento tumoral de melanomas murinos pois promovem o crescimento tumoral e são coordenadoras da mudança do perfil de macrófagos.

Melanoma is the most aggressive form of skin cancer. This tumor often presents itself resistant to therapeutic approaches. The tumor-associated angiogenesis is a critical step in tumorigenesis and the result of the action of several cytokines and growth factors such as VEGF produced in the tumor microenvironment. The extracellular galectins participate in multiple biological processes including tumor angiogenesis and metastasis, their interaction with cells present in the tumor microenvironment may occur via toll-like receptors suggesting their involvement in pro-inflammatory processes and the secretion of cytokines. We have recently shown that the absence of Gal-3 the stroma and tumor parenchyma decreases angiogenesis by interfering with the macrophage response by VEGF and / or TGFbeta1. However, the involvement of extracellular galectins on angiogenesis modulation of the immune system in the tumor microenvironment is not yet clear. This study aims is to find answers to the involvement of galectins on tumor growth and angiogenesis contributing to the study of the malignant melanoma. Our results demonstrate the involvement of galectin 1 and 3 on tumor growth and its involvement in macrophage by toll-like receptors pathway, and coordinating the modulation of the polarization profile in wild-type mice bone marrow derived macrophages. Therefore, we show these galectins act as coordinators of macrophages profile change, since inhibited extracellularly promote a reduction in tumor growth in wild-type mice inoculated with murine melanoma cells and macrophages M1 maintenance of profile in vitro. Thus, we conclude that galectins 1 and 3 extracellular are important for tumor growth of murine melanomas because they promote tumor growth and are coordinators of change macrophages profile.

Galectin-3 disruption impaired tumoral angiogenesis by reducing VEGF secretion from TGFß1-induced macrophages.

In order to study the role of galectin-3 in tumor angiogenesis associated with tumor-associated macrophages (TAM) and tumor parenchyma, the galectin-3 expression was reconstituted in Tm1 melanoma cell line that lacks this protein. Galectin-3-expressing cells (Tm1G3) and mock-vector transfected cells (Tm1N3) were injected into wild-type (WT) and galectin-3 knockout (KO) C57Bl/6 mice. Tumors originated from Tm1G3 were larger in tumor volume with enlarged functional vessels, decreased necrotic areas, and increased vascular endothelial growth factor (VEGF) protein levels. Galectin-3-nonexpressing-cells injected into WT and KO showed increased levels of transforming growth factor beta 1 (TGFß1) and, in WT animals this feature was also accompanied by increased VEGFR2 expression and its phosphorylation. In KO animals, tumors derived from galectin-3-expressing cells were infiltrated by CD68(+)-cells, whereas in tumors derived from galectin-3-nonexpressing-cells, CD68(+) cells failed to infiltrate tumors and accumulated in the periphery of the tumor mass. In vitro studies showed that Tm1G3 secreted more VEGF than Tm1N3 cells. In the latter case, TGFß1 induced VEGF production. Basal secretion of VEGF was higher in WT-bone marrow-derived macrophages (BMDM) than in KO-BMDM. TGFß1 induced secretion of VEGF only in WT-BMDM. Tm1G3-induced tumors had the Arginase I mRNA increased, which upregulated alternative macrophage (M2)/TAM induction. M2 stimuli, such as interleukin-4 (IL4) and TGFß1, increased Arginase I protein levels and galectin-3 expression in WT- BMDM, but not in cells from KO mice. Hence, we report that galectin-3 disruption in tumor stroma and parenchyma decreases angiogenesis through interfering with the responses of macrophages to the interdependent VEGF and TGFß1 signaling pathways.