Tumour microenvironment: TGFbeta: the molecular Jekyll and Hyde of cancer

Epigenetic Reprogramming of Tumor-Associated Fibroblasts in Lung Cancer: Therapeutic Opportunities

Simple Summary

Lung cancer is the leading cause of cancer death among both men and women, partly due to limited therapy responses. New avenues of knowledge are indicating that lung cancer cells do not form a tumor in isolation but rather obtain essential support from their surrounding host tissue rich in altered fibroblasts. Notably, there is growing evidence that tumor progression and even the current limited responses to therapies could be prevented by rescuing the normal behavior of fibroblasts, which are critical housekeepers of normal tissue function. For this purpose, it is key to improve our understanding of the molecular mechanisms driving the pathologic alterations of fibroblasts in cancer. This work provides a comprehensive review of the main molecular mechanisms involved in fibroblast transformation based on epigenetic reprogramming, and summarizes emerging therapeutic approaches to prevent or overcome the pathologic effects of tumor-associated fibroblasts.

Abstract

Lung cancer is the leading cause of cancer-related death worldwide. The desmoplastic stroma of lung cancer and other solid tumors is rich in tumor-associated fibroblasts (TAFs) exhibiting an activated/myofibroblast-like phenotype. There is growing awareness that TAFs support key steps of tumor progression and are epigenetically reprogrammed compared to healthy fibroblasts. Although the mechanisms underlying such epigenetic reprogramming are incompletely understood, there is increasing evidence that they involve interactions with either cancer cells, pro-fibrotic cytokines such as TGF-β, the stiffening of the surrounding extracellular matrix, smoking cigarette particles and other environmental cues. These aberrant interactions elicit a global DNA hypomethylation and a selective transcriptional repression through hypermethylation of the TGF-β transcription factor SMAD3 in lung TAFs. Likewise, similar DNA methylation changes have been reported in TAFs from other cancer types, as well as histone core modifications and altered microRNA expression. In this review we summarize the evidence of the epigenetic reprogramming of TAFs, how this reprogramming contributes to the acquisition and maintenance of a tumor-promoting phenotype, and how it provides novel venues for therapeutic intervention, with a special focus on lung TAFs.

TGF-β Signaling: From Tissue Fibrosis to Tumor Microenvironment

Transforming growth factor-β (TGF-β) signaling triggers diverse biological actions in inflammatory diseases. In tissue fibrosis, it acts as a key pathogenic regulator for promoting immunoregulation via controlling the activation, proliferation, and apoptosis of immunocytes. In cancer, it plays a critical role in tumor microenvironment (TME) for accelerating invasion, metastasis, angiogenesis, and immunosuppression. Increasing evidence suggest a pleiotropic nature of TGF-β signaling as a critical pathway for generating fibrotic TME, which contains numerous cancer-associated fibroblasts (CAFs), extracellular matrix proteins, and remodeling enzymes. Its pathogenic roles and working mechanisms in tumorigenesis are still largely unclear. Importantly, recent studies successfully demonstrated the clinical implications of fibrotic TME in cancer. This review systematically summarized the latest updates and discoveries of TGF-β signaling in the fibrotic TME.

Angiogenic Properties of NK Cells in Cancer and Other Angiogenesis-Dependent Diseases

The pathogenesis of many serious diseases, including cancer, is closely related to disturbances in the angiogenesis process. Angiogenesis is essential for the progression of tumor growth and metastasis. The tumor microenvironment (TME) has immunosuppressive properties, which contribute to tumor expansion and angiogenesis. Similarly, the uterine microenvironment (UME) exerts a tolerogenic (immunosuppressive) and proangiogenic effect on its cells, promoting implantation and development of the embryo and placenta. In the TME and UME natural killer (NK) cells, which otherwise are capable of killing target cells autonomously, enter a state of reduced cytotoxicity or anergy. Both TME and UME are rich with factors (e.g., TGF-β, glycodelin, hypoxia), which support a conversion of NK cells to the low/non-cytotoxic, proangiogenic CD56^brightCD16^low phenotype. It is plausible that the phenomenon of acquiring proangiogenic and low cytotoxic features by NK cells is not only limited to cancer but is a common feature of different angiogenesis-dependent diseases (ADDs). In this review, we will discuss the role of NK cells in angiogenesis disturbances associated with cancer and other selected ADDs. Expanding the knowledge of the mechanisms responsible for angiogenesis and its disorders contributes to a better understanding of ADDs and may have therapeutic implications.

Expression of Transforming Growth Factor Beta Isoforms in Canine Endometrium with Cystic Endometrial Hyperplasia-Pyometra Complex

Simple Summary

Pathomorphological changes and functional disorders of the uterus have long been a significant problem in the reproduction of dogs. The most commonly identified uterine disorders leading to permanent loss of fertility in dogs include cystic endometrial hyperplasia (CEH) and pyometra. These diseases may occur jointly as a CEH–pyometra complex. Despite numerous studies, the etiology of this disease remains unclear. TGF-β is considered to be one of the key factors in pathophysiological uterine disorders. The results indicate the significant expression of TGF-β1 in endometrial tissues in bitches affected by CEH–pyometra complex. Consequently, among all TGF-β isoforms, TGF-β1 is a potential biomarker involved in the regulation of a dog’s endometrium with proliferative and degenerative changes.

Abstract

Cystic endometrial hyperplasia (CEH) and pyometra are the most frequently diagnosed uterine diseases affecting bitches of different ages. Transforming growth factor beta (TGF-β) has been classified in females as a potential regulator of many endometrial changes during the estrous cycle or may be involved in pathological disorders. The aim of this study was to determine the expression of TGF-β1, -β2 and -β3 in the endometrium of bitches suffering from CEH or a CEH–pyometra complex compared to clinically healthy females (control group; CG). A significantly increased level of TGF-β1 mRNA expression was observed in the endometrium with CEH–pyometra compared to CEH and CG. Protein production of TGF-β1 was identified only in the endometrium of bitches with CEH–pyometra. An increase in TGF-β3 mRNA expression was observed in all the studied groups compared to CG. The expression of TGF-β2 mRNA was significantly higher in CEH and lower in CEH–pyometra uteri. The results indicate the presence of TGF-β cytokines in canine endometrial tissues affected by proliferative and degenerative changes. However, among all TGF-β isoforms, TGF-β1 could potentially be a key factor involved in the regulation of the endometrium in bitches with CEH–pyometra complex.

Optimizing NK Cell-Based Immunotherapy in Myeloid Leukemia: Abrogating an Immunosuppressive Microenvironment

Natural killer (NK) cells are prominent cytotoxic and cytokine-producing components of the innate immune system representing crucial effector cells in cancer immunotherapy. Presently, various NK cell-based immunotherapies have contributed to the substantial improvement in the reconstitution of NK cells against advanced-staged and high-risk AML. Various NK cell sources, including haploidentical NK cells, adaptive NK cells, umbilical cord blood NK cells, stem cell-derived NK cells, chimeric antigen receptor NK cells, cytokine-induced memory-like NK cells, and NK cell lines have been identified. Devising innovative approaches to improve the generation of therapeutic NK cells from the aforementioned sources is likely to enhance NK cell expansion and activation, stimulate ex vivo and in vivo persistence of NK cells and improve conventional treatment response of myeloid leukemia. The tumor-promoting properties of the tumor microenvironment and downmodulation of NK cellular metabolic activity in solid tumors and hematological malignancies constitute a significant impediment in enhancing the anti-tumor effects of NK cells. In this review, we discuss the current NK cell sources, highlight ongoing interventions in enhancing NK cell function, and outline novel strategies to circumvent immunosuppressive factors in the tumor microenvironment to improve the efficacy of NK cell-based immunotherapy and expand their future success in treating myeloid leukemia.

Irinotecan or Oxaliplatin: Which is the First Move for the Mate?

OBJECTIVES

The aim of the present review is to discuss the potential link between RAS, BRAF and microsatellite instability (MSI) mutational patterns and chemotherapeutic agent efficacy [Irinotecan (IRI) vs. Oxaliplatin (OXA)], and how this can potentially influence the choice of the chemotherapy backbone.

METHODS

Following a review of the research literature, all pertinent articles published in the core journals were selected for the study. The inclusion criteria regarded relevant clinical and pre-clinical studies on the topic of interest (Relationship of OXA and IRI to KRAS/BRAF mutations and MSI).

RESULTS

Excision repair cross complementation group 1 (ERCC1) expression is inhibited by KRAS mutation, making tumor cells more sensitive to OXA. Results from OPUS, COIN and PRIME trials support that no conclusive data are available for BRAF mutant population because of the small number of patients. Enhanced IRI cytotoxicity to MSI cell lines is due to the participation of some of the mismatch repair (MMR) components in various DNA repair processes and their role in the maintenance of the pro-apoptotic effect of IRI and G2/M cell arrest.

CONCLUSION

OXA and IRI are indispensable drugs for mCRC treatment and their selection must be as careful as that of targeted agents. We suggest taking into consideration the interaction between known genomic alterations and OXA and IRI activity to personalize chemotherapy in mCRC patients.

Adenosine/TGFβ axis in regulation of mammary fibroblast functions

Cancer associated fibroblasts (CAF) play a key role in cancer progression and metastasis. Diminished TGFβ response on CAF correlates with poor outcome and recurrence in cancer patients. Mechanisms behind lost TGFβ signaling on CAF are poorly understood, but, utilizing MMTV-PyMT mouse model, we have previously demonstrated that in tumor microenvironment myeloid cells, producing adenosine, contribute to downregulated TGFβ signaling on CAFs. In the current work, we performed serial in vitro studies to investigate the role of adenosine/TGFβ axis in mouse mammary fibroblast functions, i.e., proliferation, protein expression, migration, and contractility. We found that adenosine analog NECA diminished TGFβ-induced CCL5 and MMP9 expression. Additionally, we discovered that NECA completely inhibited effect of TGFβ to upregulate αSMA, key protein of cytoskeletal rearrangements, necessary for migration and contractility of fibroblasts. Our results show that TGFβ increases contractility of mouse mammary fibroblasts and human fibroblast cell lines, and NECA attenuates theses effects. Using pharmacological approach and genetically modified animals, we determined that NECA effects on TGFβ pathway occur via A_2A/A_2B adenosine receptor—AC—PKA dependent manner. Using isolated CD11b⁺ cells from tumor tissue of CD73-KO and CD39-KO animals in co-culture experiments with ATP and AMP, we confirmed that myeloid cells can affect functions of mammary fibroblasts through adenosine signaling. Our data suggest a novel mechanism of interaction between adenosine and TGFβ signaling pathways that can impact phenotype of fibroblasts in a tumor microenvironment.

Transgenic mouse models of breast cancer

Transgenic breast cancer mouse models are critical tools for preclinical studies of human breast cancer. Genetic editing of the murine mammary gland allows for modeling of abnormal genetic events frequently found in human breast cancers. Genetically engineered mouse models (GEMMs) of breast cancer employ tissue-specific genetic manipulation for tumorigenic induction within the mammary tissue. Under the transcriptional control of mammary-specific promoters, transgenic mouse models can simulate spontaneous mammary tumorigenesis by expressing one or more putative oncogenes, such as MYC, HRAS, and PIK3CA. Alternatively, the Cre-Lox system allows for tissue-specific deletion of tumor suppressors, such as p53, Rb1, and Brca1, or specific knock-in of putative oncogenes. Thus, GEMMs can be designed to implement one or more genetic events to induce mammary tumorigenesis. Features of GEMMs, such as age of transgene expression, breeding quality, tumor latency, histopathological characteristics, and propensity for local and distant metastasis, are variable and strain-dependent. This review aims to summarize currently available transgenic breast cancer mouse models that undergo spontaneous mammary tumorigenesis upon genetic manipulation, their varying characteristics, and their individual genetic manipulations that model aberrant signaling events observed in human breast cancers.

Intermittent hypoxia induces tumor immune escape in murine S180 solid tumors via the upregulation of TGF-β1 in mice

PURPOSE

Studies have shown that intermittent hypoxia (IH) alters host immune functions and promotes tumor growth. However, the relevant mechanisms of these effects have not been completely elucidated. We hypothesized that IH promotes the growth of tumors by changing cytokine levels in the tumor microenvironment and inducing immune escape.

METHODS

Sarcoma-180 (S180) solid tumor cells were injected into the right flank of Kunming mice. The mice were then randomly divided into the IH and room air (RA) groups. The mice were euthanized 2 weeks after IH exposure, and the weight of tumor tissues was measured. Next, IL-6, IL-17, IL-10, and TNF-α levels in tumor tissues were measured via enzyme linked immunosorbent assay (ELISA), and hypoxia inducible factor-1α (HIF-1α) and transforming growth factor β1 (TGF-β1) expressions were examined through Western blot analysis.

RESULTS

Two weeks of IH exposure significantly accelerated the growth of S180 solid tumors. Western blot analysis results showed that the expression levels of HIF-1α and TGF-β1 in S180 tumors in the IH group were significantly upregulated compared with those in the RA group. ELISA results showed that compared with the RA group, the IH group had significantly increased TNF-α and IL-10 (P < 0.05) and significantly decreased IL-17 (P < 0.05).

CONCLUSION

IH might promote the growth of S180 solid tumors by inhibiting the antitumor immune response and inducing tumor immune escape via the upregulation of TGF-β1.

A cytokine in turmoil: Transforming growth factor beta in cancer

Cancer remains one of the debilitating health threats to mankind in view of its incurable nature. Many factors are complicit in the initiation, progression and establishment of cancers. Early detection of cancer is the only window of hope that allows for appreciable management and possible limited survival. However, understanding of cancer biology and knowledge of the key factors that interplay at multi-level in the initiation and progression of cancer may hold possible avenues for cancer treatment and management. In particular, dysregulation of growth factor signaling such as that of transforming growth factor beta (TGF-β) and its downstream mediators play key roles in various cancer subtypes. Expanded understanding of the context/cell type-dependent roles of TGF-β and its downstream signaling mediators in cancer may provide leads for cancer pharmacotherapy. Reliable information contained in original articles, reviews, mini-reviews and expert opinions on TGF-β, cancer and the specific roles of TGF-β signaling in various cancer subtypes were retrieved from major scientific data bases including PubMed, Scopus, Medline, Web of Science core collections just to mention but a sample by using the following search terms: TGF-β in cancer, TGF-β and colorectal cancer, TGF-β and brain cancer, TGF-β in cancer initiation, TGF-β and cell proliferation, TGF-β and cell invasion, and TGF-β-based cancer therapy. Retrieved information and reports were carefully examined, contextualized and synchronized into a coherent scientific content to highlight the multiple roles of TGF-β signaling in normal and cancerous cells. From a conceptual standpoint, development of pharmacologically active agents that exert non-specific inhibitory effects on TGF-β signaling on various cell types will undoubtedly lead to a plethora of serious side effects in view of the multi-functionality and pleiotropic nature of TGF-β. Such non-specific targeting of TGF-β could derail any beneficial therapeutic intention associated with TGF-β-based therapy. However, development of pharmacologically active agents designed specifically to target TGF-β signaling in cancer cells may improve cancer pharmacotherapy. Similarly, specific targeting of downstream mediators of TGF-β such as TGF-β type 1 and II receptors (TβRI and TβRII), receptor-mediated Smads, mitogen activated protein kinase (MAPK) and importing proteins in cancer cells may be crucial for cancer pharmacotherapy.

Natural Killer Cell Interactions With Myeloid Derived Suppressor Cells in the Tumor Microenvironment and Implications for Cancer Immunotherapy

The tumor microenvironment (TME) is a complex and heterogeneous environment composed of cancer cells, tumor stroma, a mixture of tissue-resident and infiltrating immune cells, secreted factors, and extracellular matrix proteins. Natural killer (NK) cells play a vital role in fighting tumors, but chronic stimulation and immunosuppression in the TME lead to NK cell exhaustion and limited antitumor functions. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of myeloid cells with potent immunosuppressive activity that gradually accumulate in tumor tissues. MDSCs interact with innate and adaptive immune cells and play a crucial role in negatively regulating the immune response to tumors. This review discusses MDSC-mediated NK cell regulation within the TME, focusing on critical cellular and molecular interactions. We review current strategies that target MDSC-mediated immunosuppression to enhance NK cell cytotoxic antitumor activity. We also speculate on how NK cell-based antitumor immunotherapy could be improved.

N-cadherin mediates the migration of bone marrow-derived mesenchymal stem cells toward breast tumor cells

Rationale: Bone marrow-derived mesenchymal stem cells (BM-MSCs) recruited into breast tumors regulate the behavior of tumor cells via various mechanisms and affect clinical outcomes. Although signaling molecules, such as transforming growth factor β (TGF-β), are known to transmit signals between BM-MSCs and breast tumor cells for recruiting BM-MSCs, it is unclear which specific intrinsic molecules involved in cell motility mediate the migration of BM-MSCs into breast tumor. It is also unclear as to how specific intrinsic molecules contribute to the migration. Methods: Conditioned medium (CM) from breast tumor cells (MCF-7 and MDA-MB-231) that simulates breast tumor secreting TGF-β was used to examine the migration of BM-MSCs into breast tumors. A three-dimensional migration assay was performed to investigate the collective migration of BM-MSCs, maintaining cell-cell adhesion, toward breast tumor cells. Results: N-cadherin formed adherens junction-like structures on the intercellular borders of BM-MSCs, and TGF-β increased the expression of N-cadherin on these borders. Knockdown of Smad4 impaired the TGF-β-mediated increase in N-cadherin expression in BM-MSCs, but inhibitors of non-canonical TGF-β pathways, such as extracellular signal-regulated kinases, Akt, and p38, did not affect it. siRNA-mediated knockdown of N-cadherin and Smad4 impaired the migration of BM-MSCs in response to TGF-β. Conditioned medium from breast tumor cells also enhanced the expression of N-cadherin in BM-MSCs, but inactivation of TGF-β type 1 receptor (TGFBR1) with SB505124 and TGFBR1 knockdown abolished the increase in N-cadherin expression. BM-MSCs collectively migrated toward CM from MDA-MB-231 in vitro while maintaining cell-cell adhesion through N-cadherin. Knockdown of N-cadherin abolished the migration of BM-MSCs toward the CM from breast tumor cells. Conclusion: In the present study, we identified N-cadherin, an intrinsic transmembrane molecule in adherens junction-like structures, on BM-MSCs as a mediator for the migration of these cells toward breast tumor. The expression of N-cadherin increases on the intercellular borders of BM-MSCs through the TGF-β canonical signaling and they collectively migrate in response to breast tumor cells expressing TGF-β via N-cadherin-dependent cell-cell adhesion. We, herein, introduce a novel promising strategy for controlling and re-engineering the breast tumor microenvironment.

Syndecan-1 modulates the invasive potential of endometrioma via TGF-β signalling in a subgroup of women with endometriosis

STUDY QUESTION

What is the physiological role of transforming growth factor-beta (TGF-β1) and syndecans (SDC1, SDC4) in endometriotic cells in women with endometriosis?

SUMMARY ANSWER

We observed an abnormal, pro-invasive phenotype in a subgroup of samples with ovarian endometriosis, which was reversed by combining gene silencing of SDC1 with the TGF-β1 treatment.

WHAT IS KNOWN ALREADY

Women with endometriosis express high levels of TGF-β1 and the proteoglycan co-receptors SDC1 and SDC4 within endometriotic cysts. However, how SDC1 and SDC4 expression is regulated by TGF-β1 and the physiological significance of the high expression in endometriotic cysts remains unknown as does the potential role in disease severity.

STUDY DESIGN, SIZE, DURATION

We utilized a pre-validated panel of stem- and cancer cell-associated markers on endometriotic tissue (n = 15) to stratify subgroups of women with endometriosis. Furthermore, CD90+CD73+CD105+ (SC+) endometriotic stromal cells from these patient subgroups were explored for their invasive behaviour in vitro by transient gene inhibition of SDC1 or SDC4, both in the presence or absence of TGF-β1 treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometriotic cyst biopsies (n = 15) were obtained from women diagnosed with ovarian endometriosis (ASRM Stage III-IV). Gene expression variability was assessed on tissue samples by applying gene clustering tools for the dataset generated from the pre-validated panel of markers. Three-dimensional (3D) spheroids from endometriotic SC+ were treated in vitro with increasing doses of TGF-β1 or the TGFBRI/II inhibitor Ly2109761 and assessed for SDC1, SDC4 expression and in vitro 3D-spheroid invasion. Transcriptomic signatures from the invaded 3D spheroids were evaluated upon combining transient gene silencing of SDC1 or SDC4, both in presence or absence of TGF-β1 treatment. Furthermore, nanoscale changes on the surface of endometriotic cells were analysed after treatment with TGF-β1 or TGFBRI/II inhibitor using atomic force microscopy.

MAIN RESULTS AND THE ROLE OF CHANCE

Gene clustering analysis revealed that endometriotic tissues displayed variability in their gene expression patterns; a small subgroup of samples (2/15, Endo-hi) exhibited high levels of SDC1, SDC4 and molecules involved in TGF-β signalling (TGF-β1, ESR1, CTNNB1, SNAI1, BMI1). The remaining endometriotic samples (Endo-lo) showed a uniform, low gene expression profile. Three-dimensional spheroids derived from Endo-hi SC+ but not Endo-lo SC+ samples showed an aberrant expression of SDC1 and exhibited enhanced 3D-spheroid invasion in vitro, upon rhTGF-β1 treatment. However, this abnormal, pro-invasive response of Endo-hi SC+ was reversed upon gene silencing of SDC1 with the TGF-β1 treatment. Interestingly, transcriptomic signatures of 3D spheroids silenced for SDC1 and consecutively treated with TGF-β1, showed a down-regulation of cancer-associated pathways such as WNT and GPCR signalling.

LARGE SCALE DATA

Transcriptomic data were deposited in NCBI's Gene Expression Omnibus (GEO) and could be retrieved using GEO series accession number: GSE135122.

LIMITATIONS, REASONS FOR CAUTION

It is estimated that about 2.5% of endometriosis patients have a potential risk for developing ovarian cancer later in life. It is possible that the pro-oncogenic molecular changes observed in this cohort of endometriotic samples may not correlate with clinical occurrence of ovarian cancer later in life, thus a validation will be required.

WIDER IMPLICATIONS OF THE FINDINGS

This study emphasizes the importance of interactions between syndecans and TGF-β1 in the pathophysiology of endometriosis. We believe that this knowledge could be important in order to better understand endometriosis-associated complications such as ovarian cancer or infertility.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Cancerfonden (CAN 2016/696), Radiumhemmets Forskningsfonder (Project no. 154143 and 184033), EU MSCA-RISE-2015 project MOMENDO (691058), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695) and Karolinska Institute. Authors do not have any conflict of interest.

Tgf-β1 transcriptionally promotes 90K expression: possible implications for cancer progression

The 90K protein, also known as Mac-2 BP or LGALS3BP, can activate the immune response in part by increasing major histocompatibility (MHC) class I levels. In studies on a non-immune cell model, the rat FRTL-5 cell line, we observed that transforming growth factor (TGF)-β1, like γ-interferon (IFN), increased 90K levels, despite its immunosuppressive functions and the ability to decrease MHC class I. To explain this paradoxical result, we investigated the mechanisms involved in the TGF-β1 regulation of 90K expression with the aim to demonstrate that TGF-β1 utilizes different molecular pathways to regulate the two genes. We found that TGF-β1 was able to increase the binding of Upstream Stimulatory Factors, USF1 and USF2, to an E-box element, CANNTG, at -1926 to -1921 bp, upstream of the interferon response element (IRE) in the 90K promoter. Thyrotropin (TSH) suppressed constitutive and γ-IFN-induced 90K expression by decreasing USF binding to the E-box. TGF-β1 was able to overcome TSH suppression at the transcriptional level by increasing USF binding to the E-box. We suggest that the ability of TGF-β1 to increase 90K did not result in an increase in MHC class I because of a separate suppressive action of TGF-β1 directly on the MHC class I gene. We propose that the increased levels of 90K may play a role, rather than in immune response, in the context of the TGF-β1-induced changing of the cellular microenvironment that predisposes to cell motility and cancer progression. Consistently, analyzing the publicly available cancer patient data sets cBioPortal, we found that 90K expression directly correlated with TGF-β1 and USFs and that high levels of 90K were significantly associated with increased mortality in patients affected by different types of cancer.

GTSE1 promotes SNAIL1 degradation by facilitating its nuclear export in hepatocellular carcin oma cells

Snail family transcriptional repressor 1 (SNAIL1) is a master inducer of the epithelial-to-mesenchymal transition (EMT) process, contributing to tumor metastasis and recurrence. Our previous study reported that G₂ and S phase-expressed-1 (GTSE1) served a role in regulating SNAIL1 expression in hepatocellular carcinoma (HCC). However, the underlying mechanism remains unknown. Therefore, the present study aimed to reveal the regulatory mechanism of GTSE1 on SNAIL1 expression using in vitro assays performed in HCC cell models. It was demonstrated that endogenous SNAIL1 expression was downregulated and upregulated by GTSE1 overexpression or small interfering RNA-mediated knockdown, respectively. Via cycloheximide chase experiments, it was identified that GTSE1 overexpression increased the protein turnover of SNAIL1, while knockdown of GTSE1 reduced its degradation rate. Furthermore, it was demonstrated that GTSE1 overexpression induced the cytoplasmic expression of SNAIL1 using immunofluorescence and subcellular fractionation methods. The nuclear export inhibitor leptomycin B was able to decrease the cytoplasmic retention of SNAIL1 caused by GTSE1 overexpression. In addition, TGF-βI treatment increased both the mRNA and protein expression levels of GTSE1, and decreased the protein expression level of SNAIL1 without affecting its mRNA transcription in Huh7 cells. It was also found that TGF-β signaling could upregulate the transcription of GTSE1 expression by transactivating the Smad binding elements in the GTSE1 promoter. Moreover, the TGF-βI-induced decrease in SNAIL1 protein expression was GTSE1-dependent in Huh7 cells. In conclusion, the current study provides a novel mechanism via which GTSE1 affects the stability of SNAIL1 by regulating its subcellular localization in HCC cells.

Triple-Negative Breast Cancer Cells Recruit Neutrophils by Secreting TGF-β and CXCR2 Ligands

Tumor associated neutrophils (TANs) are frequently detected in triple-negative breast cancer (TNBC). Recent studies also reveal the importance of neutrophils in promoting tumor progression and metastasis during breast cancer. However, the mechanisms regulating neutrophil trafficking to breast tumors are less clear. We sought to determine whether neutrophil trafficking to breast tumors is determined directly by the malignant potential of cancer cells. We found that tumor conditioned media (TCM) harvested from highly aggressive, metastatic TNBC cells induced a polarized morphology and robust neutrophil migration, while TCM derived from poorly aggressive estrogen receptor positive (ER+) breast cancer cells had no activity. In a three-dimensional (3D) type-I collagen matrix, neutrophils migrated toward TCM from aggressive breast cancer cells with increased velocity and directionality. Moreover, in a neutrophil-tumor spheroid co-culture system, neutrophils migrated with increased directionality towards spheroids generated from TNBC cells compared to ER+ cells. Based on these findings, we next sought to characterize the active factors secreted by TNBC cell lines. We found that TCM-induced neutrophil migration is dependent on tumor-derived chemokines, and screening TCM elution fractions based on their ability to induce polarized neutrophil morphology revealed the molecular weight of the active factors to be around 12 kDa. TCM from TNBC cell lines contained copious amounts of GRO (CXCL1/2/3) chemokines and TGF-β cytokines compared to ER+ cell-derived TCM. TCM activity was inhibited by simultaneously blocking receptors specific to GRO chemokines and TGF-β, while the activity remained intact in the presence of either single receptor inhibitor. Together, our findings establish a direct link between the malignant potential of breast cancer cells and their ability to induce neutrophil migration. Our study also uncovers a novel coordinated function of TGF-β and GRO chemokines responsible for guiding neutrophil trafficking to the breast tumor.

Dopamine Pathway Mediated by DRD5 Facilitates Tumor Growth via Enhancing Warburg Effect in Esophageal Cancer

Esophageal cancer (EC) is among the most malignant cancers globally due to its aggressiveness and poor survival. To set off from the inflammatory tumor immune microenvironment, we analyzed tumor tissues of EC patients with or without lymphatic metastasis to explore the importance of cancer cell derived neurotransmitters. Results have emphasized that the accumulation of dopamine but not other neurotransmitters could be observed in EC tumor tissue of patients, especially those who are bearing lymphatic metastasis. Transcriptional analysis of mentioned tissues was also performed to filter out key enzymes involved in dopamine pathway including tyrosine hydroxylase (TH), DOPA decarboxylase (DCC), monoamine oxidase (MAO), etc. Further analysis on tumor tissues of patients indicated that dopamine receptor D5 was aberrantly upregulated and co-located with TH. Both in vitro and in vivo tests have demonstrated that dopamine could stimulate the proliferation and outgrowth of EC tumor cells via the DRD5 mediated pathway. The exploration of mechanism has unveiled that activation of the dopamine pathway significantly enhanced the uptake of glucose and production of lactate of EC tumor cells. It can also facilitate the extracellular acid rate (ECAR), dedicating that DRD5-mediated activated dopamine pathway could effectively form and trigger Warburg effect, which is modulated by the cross-talk of mTOR and AKT pathway. Our results would unveil the relationship between cancer derived neurotransmitters and inflammatory tumor immune microenvironment, thus provide potential therapeutic targets and novel clinical strategy towards metastatic EC.

Novel therapies emerging in oncology to target the TGF-β pathway

The TGF-β signaling pathway governs key cellular processes under physiologic conditions and is deregulated in many pathologies, including cancer. TGF-β is a multifunctional cytokine that acts in a cell- and context-dependent manner as a tumor promoter or tumor suppressor. As a tumor promoter, the TGF-β pathway enhances cell proliferation, migratory invasion, metastatic spread within the tumor microenvironment and suppresses immunosurveillance. Collectively, the pleiotropic nature of TGF-β signaling contributes to drug resistance, tumor escape and undermines clinical response to therapy. Based upon a wealth of preclinical studies, the TGF-β pathway has been pharmacologically targeted using small molecule inhibitors, TGF-β-directed chimeric monoclonal antibodies, ligand traps, antisense oligonucleotides and vaccines that have been now evaluated in clinical trials. Here, we have assessed the safety and efficacy of TGF-β pathway antagonists from multiple drug classes that have been evaluated in completed and ongoing trials. We highlight Vactosertib, a highly potent small molecule TGF-β type 1 receptor kinase inhibitor that is well-tolerated with an acceptable safety profile that has shown efficacy against multiple types of cancer. The TGF-β ligand traps Bintrafusp alfa (a bifunctional conjugate that binds TGF-β and PD-L1), AVID200 (a computationally designed trap of TGF-β receptor ectodomains fused to an Fc domain) and Luspatercept (a recombinant fusion that links the activin receptor IIb to IgG) offer new ways to fight difficult-to-treat cancers. While TGF-β pathway antagonists are rapidly emerging as highly promising, safe and effective anticancer agents, significant challenges remain. Minimizing the unintentional inhibition of tumor-suppressing activity and inflammatory effects with the desired restraint on tumor-promoting activities has impeded the clinical development of TGF-β pathway antagonists. A better understanding of the mechanistic details of the TGF-β pathway should lead to more effective TGF-β antagonists and uncover biomarkers that better stratify patient selection, improve patient responses and further the clinical development of TGF-β antagonists.

Granulocytes and Cells of Granulocyte Origin-The Relevant Players in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancy and cause of cancer death worldwide, and it still remains a therapeutic challenge for western medicine. There is strong evidence that, in addition to genetic predispositions, environmental factors have also a substantial impact in CRC development. The risk of CRC is attributed, among others to dietary habits, alcohol consumption, whereas physical activity, food containing dietary fiber, dairy products, and calcium supplements have a protective effect. Despite progress in the available therapies, surgery remains a basic treatment option for CRC. Implementation of additional methods of treatment such as chemo- and/or targeted immunotherapy, improved survival rates, however, the results are still far from satisfactory. One of the reasons may be the lack of deeper understanding of the interactions between the tumor and different types of cells, including tumor infiltrating granulocytes. While the role of neutrophils is quite well explored in many cancers, role of eosinophils and basophils is often underestimated. As part of this review, we focused on the function of different granulocyte subsets in CRC, emphasizing the beneficial role of eosinophils and basophils, as well as dichotomic mode of neutrophils action. In addition, we addressed the current knowledge on cells of granulocyte origin, specifically granulocytic myeloid derived suppressor cells (Gr-MDSCs) and their role in development and progression of CRC.

Bromelain a Potential Bioactive Compound: A Comprehensive Overview from a Pharmacological Perspective

Bromelain is an effective chemoresponsive proteolytic enzyme derived from pineapple stems. It contains several thiol endopeptidases and is extracted and purified via several methods. It is most commonly used as an anti-inflammatory agent, though scientists have also discovered its potential as an anticancer and antimicrobial agent. It has been reported as having positive effects on the respiratory, digestive, and circulatory systems, and potentially on the immune system. It is a natural remedy for easing arthritis symptoms, including joint pain and stiffness. This review details bromelain's varied uses in healthcare, its low toxicity, and its relationship to nanoparticles. The door of infinite possibilities will be opened up if further extensive research is carried out on this pineapple-derived enzyme.

Enhancing programmed cell death protein 1 axis inhibition in head and neck squamous cell carcinoma: Combination immunotherapy

Anti-programmed cell death protein 1 immunotherapy has become the new standard in the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). However, the population that benefits is small, warranting drug combinations and novel approaches. HNSCC is a profoundly immunosuppressive disease, characterized by the interplay among different immune regulatory pathways. As clinical trials evaluating immunotherapy combinations in patients with HNSCC have started producing preliminary results, preclinical evidence on potential new targets for combination immunotherapy continues to accumulate. This review summarizes emerging clinical and preclinical data on immunotherapy combinations for the treatment of HNSCC.

The Dual Role of STAT1 in Ovarian Cancer: Insight Into Molecular Mechanisms and Application Potentials

The signal transducer and activator of transcription 1 (STAT1) is a transducer protein and acts as a transcription factor but its role in ovarian cancer (OC) is not completely understood. Practically, there are two-faced effects of STAT1 on tumorigenesis in different kinds of cancers. Existing evidence reveals that STAT1 has both tumor-suppressing and tumor-promoting functions involved in angiogenesis, cell proliferation, migration, invasion, apoptosis, drug resistance, stemness, and immune responses mainly through interacting and regulating target genes at multiple levels. The canonical STAT1 signaling pathway shows that STAT1 is phosphorylated and activated by the receptor-activated kinases such as Janus kinase in response to interferon stimulation. The STAT1 signaling can also be crosstalk with other signaling such as transforming growth factor-β signaling involved in cancer cell behavior. OC is often diagnosed at an advanced stage due to symptomless or atypical symptoms and the lack of effective detection at an early stage. Furthermore, patients with OC often develop chemoresistance and recurrence. This review focuses on the multi-faced role of STAT1 and highlights the molecular mechanisms and biological functions of STAT1 in OC.

Genetic and Non-Genetic Mechanisms Underlying Cancer Evolution

Simple Summary

Our manuscript summarizes the up-to-date data on the complex and dynamic nature of adaptation mechanisms and evolutionary processes taking place during cancer initiation, development and progression. Although for decades cancer has been viewed as a process governed by genetic mechanisms, it is becoming more and more clear that non-genetic mechanisms may play an equally important role in cancer evolution. In this review, we bring together these fundamental concepts and discuss how those tightly interconnected mechanisms lead to the establishment of highly adaptive quickly evolving cancers. Furthermore, we argue that in depth understanding of cancer progression from the evolutionary perspective may allow the prediction and direction of the evolutionary path of cancer populations towards drug sensitive phenotypes and thus facilitate the development of more effective anti-cancer approaches.

Abstract

Cancer development can be defined as a process of cellular and tissular microevolution ultimately leading to malignancy. Strikingly, though this concept has prevailed in the field for more than a century, the precise mechanisms underlying evolutionary processes occurring within tumours remain largely uncharacterized and rather cryptic. Nevertheless, although our current knowledge is fragmentary, data collected to date suggest that most tumours display features compatible with a diverse array of evolutionary paths, suggesting that most of the existing macro-evolutionary models find their avatar in cancer biology. Herein, we discuss an up-to-date view of the fundamental genetic and non-genetic mechanisms underlying tumour evolution with the aim of concurring into an integrated view of the evolutionary forces at play throughout the emergence and progression of the disease and into the acquisition of resistance to diverse therapeutic paradigms. Our ultimate goal is to delve into the intricacies of genetic and non-genetic networks underlying tumour evolution to build a framework where both core concepts are considered non-negligible and equally fundamental.

TGF-β-induced cell motility requires downregulation of ARHGAPs to sustain Rac1 activity

Transforming growth factor-β (TGF-β) signaling promotes cancer progression. In particular, the epithelial-mesenchymal transition (EMT) induced by TGF-β is considered crucial to the malignant phenotype of cancer cells. Here, we report that the EMT-associated cellular responses induced by TGF-β are mediated by distinct signaling pathways that diverge at Smad3. By expressing chimeric Smad1/Smad3 proteins in SMAD3 knockout A549 cells, we found that the β4 region in the Smad3 MH1 domain is essential for TGF-β-induced cell motility, but is not essential for other EMT-associated responses including epithelial marker downregulation. TGF-β was previously reported to enhance cell motility by activating Rac1 via phosphoinositide 3-kinase. Intriguingly, TGF-β-dependent signaling mediated by Smad3's β4 region causes the downregulation of multiple mRNAs that encode GTPase activating proteins that target Rac1 (ARHGAPs), thereby attenuating Rac1 inactivation. Therefore, two independent pathways downstream of TGF-β type I receptor contribute cooperatively to sustained Rac1 activation, thereby leading to enhanced cell motility.

On-demand responsive nanoplatform mediated targeting of CAFs and down-regulating mtROS-PYK2 signaling for antitumor metastasis

The desmoplastic tumor microenvironment (DTME), including overexpressed stromal cells and extracellular matrix, formed the first barrier for the accumulation and penetration of nanoparticles in tumors, which compromised the therapeutic efficacy and prognosis. In some metastatic cells, overactivity of the tricarboxylic cycle could overload the electron transport chain resulting in increased mtROS production, which triggered the mitochondria-driven tumor migration and metastasis. Hence, we developed HPBC@TRP/NPs for down-regulating the mtROS-PYK2 pathway and remodeling the DTME to inhibit tumor growth and metastasis for the first time. TPP-RSV prodrugs were synthesized and targeted at mitochondria, resulting in the scavenging of mtROS, lower PYK2 expression, and activation of the mitochondria-driven apoptotic pathway. Pirfenidone fully remodeled the DTME through inhibiting the expression of CAFs, hyaluronan and collagen I, thereby reducing IFP, eliminating the immunosuppressive microenvironment by decreasing the expression of TGF-β, and increasing the infiltration of cytotoxic T lymphocytes. The combination therapy of different mechanisms via targeting the mtROS-PYK2 pathway and CAFs might provide deeper insights into the inhibition of malignant breast cancer growth and metastasis.

MiR-21-5p Induces Pyroptosis in Colorectal Cancer via TGFBI

Pyroptosis is a distinct form of programmed cell death in eukaryotic cells that has garnered increasing attention in cancer-related research. Moreover, although miR-21 has been reported as abnormally expressed in colorectal cancer, due to a lack of in-depth research on the transcriptional regulation mechanisms of miR-21, its clinical usage remains limited. Our study is the first, to our knowledge, to compare the clinical manifestations and laboratory phenotypes associated with miR-21-3p and miR-21-5p. Morphologically, the transfection of miR-21-3p or miR-21-5p inhibitors, as well as miR-21-5p mimics into HCT-116 and HT-29 cell lines, induced cell death. Surprisingly, overexpression of miR-21-5p induced cell death more strongly than its knockdown. Mechanistic studies of miR-21-5p overexpression revealed that various inflammatory factors including IL-1β and IL-18 were released, while pyroptosis-associated mRNAs were upregulated and proteins were activated. Moreover, miR-21-5p was found to act as a downstream factor to significantly and directly regulate transforming growth factor beta-induced (TGFB1). Specifically, miR-21-5p overexpression caused downregulation of TGFBI, which may have led to pyroptosis. Collectively, we revealed that miR-21-5p induces pyroptosis in colorectal cancer via TGFBI regulation, thereby providing important mechanistic insights into its antitumor effects and expanding its potential for clinical applications.

Piperlongumine inhibits the growth of non-small cell lung cancer cells via the miR-34b-3p/TGFBR1 pathway

BACKGROUND

Non-small cell lung cancer is a common type of lung cancer. Piperlongumine (PL), which is extracted from the roots of piperaceae plant, long pepper, and peppercorn, is an alkaloid amide that inhibits tumor growth and metastasis. However, whether it affects lung cancer cells remains unclear.

METHODS

We assessed the effects of PL on the proliferation and apoptosis of A549 and H1299 NSCLC cell lines.

RESULTS

PL was mildly toxic to normal human bronchial epithelial cells and significantly suppressed growth and facilitated apoptosis of A549 and H1299 cells. It also upregulated microRNA (miR)-34b-3p and downregulated the transforming growth factor beta type I receptor (TGFBR1). The dual-luciferase reporter assay showed that TGFBR1 is a target gene of miR-34b-3p. Silencing of miR-34b-3p or overexpression of TGFBR1 partially attenuated the effects of PL on A549 and H1299 cells.

CONCLUSIONS

PL inhibits proliferation and induces apoptosis of A549 and H1299 cells by upregulating miR-34b-3p and modulating TGFBR1 signaling pathway.

Inflammation Mediates the Development of Aggressive Breast Cancer Following Radiotherapy

PURPOSE

Women treated with radiotherapy before 30 years of age have increased risk of developing breast cancer at an early age. Here, we sought to investigate mechanisms by which radiation promotes aggressive cancer.

EXPERIMENTAL DESIGN

The tumor microenvironment (TME) of breast cancers arising in women treated with radiotherapy for Hodgkin lymphoma was compared with that of sporadic breast cancers. To investigate radiation effects on carcinogenesis, we analyzed tumors arising from Trp53-null mammary transplants after irradiation of the target epithelium or host using immunocompetent and incompetent mice, some of which were treated with aspirin.

RESULTS

Compared with age-matched specimens of sporadic breast cancer, radiation-preceded breast cancers (RP-BC) were characterized by TME rich in TGFβ, cyclooxygenase 2, and myeloid cells, indicative of greater immunosuppression, even when matched for triple-negative status. The mechanism by which radiation impacts TME construction was investigated in carcinomas arising in mice bearing Trp53-null mammary transplants. Immunosuppressive TMEs (iTME) were recapitulated in mice irradiated before transplantation, which implicated systemic immune effects. In nu/nu mice lacking adaptive immunity irradiated before Trp53-null mammary transplantation, cancers also established an iTME, which pointed to a critical role for myeloid cells. Consistent with this, irradiated mammary glands contained more macrophages and human cells cocultured with polarized macrophages underwent dysplastic morphogenesis mediated by IFNγ. Treating mice with low-dose aspirin for 6 months postirradiation prevented establishment of an iTME and resulted in less aggressive tumors.

CONCLUSIONS

These data show that radiation acts via nonmutational mechanisms to promote markedly immunosuppressive features of aggressive, RP-BCs.

Salinomycin suppresses TGF-β1-induced EMT by down-regulating MMP-2 and MMP-9 via the AMPK/SIRT1 pathway in non-small cell lung cancer

Salinomycin (Sal) is a recently identified anti-tumor drug for treating several types of solid tumor; however, its effects on the migratory and invasive properties of non-small cell lung cancer (NSCLC) remain unclear. This study investigated the inhibitory effect underlying mechanisms of Salon transforming growth factor-β1 (TGF-β1)-induced epithelial-to-mesenchymal transition (EMT) and cell migration. Sal solidly blocked cell migration and invasion enhancement by TGF-β1-induced EMT, through recovering E-cadherin loss and suppressing mesenchymal markers induction, as well as TGF-β1-mediated AMPK/SIRT signaling activity upregulation. The pharmacologic inhibition or knockdown of AMPK or SIRT1 can act synergistically with Sal to inhibit TGF-β1-induced MMP-2 and MMP-9. In contrast, AMPK or SIRT1 upregulation can protect against TGF-β1-induced MMP-2 and MMP-9 inhibition by Sal. Next we demonstrated that the MMP-2 and MMP-9 knockdown can act synergistically with Sal to inhibit TGF-β1-induced EMT. Moreover, treatment of PMA of MMP activator increased TGF-β1-induced MMP-2 and MMP-9, even with Sal. Our results demonstrate that Sal suppresses TGF-β1-induced EMT by downregulating MMP-2 and MMP-9 through the AMPK/SIRT pathway, thereby inhibiting lung cancer cell migration and invasion.

Flow cytometry detection of cell type-specific expression of programmed death receptor ligand-1 (PD-L1) in colorectal cancer specimens

Aim

PD-1/PD-L1 blockade therapy is now widely used for the treatment of advanced malignancies. Although PD-L1 is known to be expressed by various host cells as well as tumor cells, the role of PD-L1 on non-malignant cells and its clinical significance is unknown. We evaluated cell type-specific expression of PD-L1 in colorectal cancer (CRC) specimens using multicolor flow cytometry.

Methods

Single cell suspensions were made from 21 surgically resected CRC specimens, and immunostained with various mAbs conjugated with different fluorescent dyes. Tumor cells, stromal cells, and immune cells were identified as CD326(+), CD90(+) and CD45(+) phenotype, respectively. CD11b(+) myeloid cells, CD19(+) B cells and CD4(+) or CD8(+) T cells were also stained in different samples, and their frequencies in the total cell population and the ratio of PD-L1(+) cells to each phenotype were determined.

Results

PD-L1 was expressed by all the cell types. The ratio of PD-L1(+) cells to CD326(+) tumor cells was 19.1% ± 14.0%, lower than those for CD90(+) stromal cells (39.6% ± 16.0%) and CD11b(+) myeloid cells (31.9% ± 14.3%). The ratio of PD-L1(+) cells in tumor cells correlated strongly with the ratio in stromal cells, while only weakly with that in myeloid cells. Tumor cells were divided into two populations by CD326 expression levels, and the PD-L1 positive ratios were inversely correlated with the rate of CD326 highly expressing cells as well as mean fluorescein intensity of CD326 in tumor cells, while positively correlated with the frequencies of stromal cells or myeloid cells in CRC.

Conclusion

PD-L1 is differentially expressed on various cell types in CRC. PD-L1 on tumor cells may be upregulated together with CD326 downregulation in the process of epithelial mesenchymal transition. Quantification of cell type-specific expression of PD-L1 using multicolor flow cytometry may provide useful information for the immunotherapy of solid tumors.

Natural Killer Cell Defects in Breast Cancer: A Key Pathway for Tumor Evasion

As the most important innate immune component cancers invader, natural killer (NK) cells have a magnificent role in antitumor immunity without any prior sensitization. Different subsets of NK cells have distinct responses during tumor cell exposure, according to their phenotypes and environments. Their function is induced mainly by the activity of both inhibitory and activating receptors against cancerous cells. Since the immunosuppression in the tumor microenvironment of breast cancer patients has directly deteriorated the phenotype and disturbed the function of NK cells, recruiting compensatory mechanisms indicate promising outcomes for immunotherapeutic approaches. These evidences accentuate the importance of NK cell distinct features in protection against breast tumors. In this review, we discuss the several mechanisms involved in NK cells suppression which consequently promote tumor progression and disease recurrence in patients with breast cancer.

Heparanase and the hallmarks of cancer

Heparanase is the only mammalian enzyme that cleaves heparan sulphate, an important component of the extracellular matrix. This leads to the remodelling of the extracellular matrix, whilst liberating growth factors and cytokines bound to heparan sulphate. This in turn promotes both physiological and pathological processes such as angiogenesis, immune cell migration, inflammation, wound healing and metastasis. Furthermore, heparanase exhibits non-enzymatic actions in cell signalling and in regulating gene expression. Cancer is underpinned by key characteristic features that promote malignant growth and disease progression, collectively termed the 'hallmarks of cancer'. Essentially, all cancers examined to date have been reported to overexpress heparanase, leading to enhanced tumour growth and metastasis with concomitant poor patient survival. With its multiple roles within the tumour microenvironment, heparanase has been demonstrated to regulate each of these hallmark features, in turn highlighting the need for heparanase-targeted therapies. However, recent discoveries which demonstrated that heparanase can also regulate vital anti-tumour mechanisms have cast doubt on this approach. This review will explore the myriad ways by which heparanase functions as a key regulator of the hallmarks of cancer and will highlight its role as a major component within the tumour microenvironment. The dual role of heparanase within the tumour microenvironment, however, emphasises the need for further investigation into defining its precise mechanism of action in different cancer settings.

Dysregulation of Transcription Factor Activity During Formation of Cancer-Associated Fibroblasts

The reciprocal interactions between cancer cells and the quiescent fibroblasts leading to the activation of cancer-associated fibroblasts (CAFs) serve an important role in cancer progression. Here, we investigated the activation of transcription factors (TFs) in prostate fibroblasts (WPMY cell line) co-cultured with normal prostate or tumorous cells (RWPE1 and RWPE2 cell lines, respectively). After indirect co-cultures, we performed mRNA-seq and predicted TF activity using mRNA expression profiles with the Systems EPigenomics Inference of Regulatory Activity (SEPIRA) package and the GTEx and mRNA-seq data of 483 cultured fibroblasts. The initial differential expression analysis between time points and experimental conditions showed that co-culture with normal epithelial cells mainly promotes an inflammatory response in fibroblasts, whereas with the cancerous epithelial, it stimulates transformation by changing the expression of the genes associated with microfilaments. TF activity analysis revealed only one positively regulated TF in the RWPE1 co-culture alone, while we observed dysregulation of 45 TFs (7 decreased activity and 38 increased activity) uniquely in co-culture with RWPE2. Pathway analysis showed that these 45 dysregulated TFs in fibroblasts co-cultured with RWPE2 cells may be associated with the RUNX1 and PTEN pathways. Moreover, we showed that observed dysregulation could be associated with FER1L4 expression. We conclude that phenotypic changes in fibroblast responses to co-culturing with cancer epithelium result from orchestrated dysregulation of signaling pathways that favor their transformation and motility rather than proinflammatory status. This dysregulation can be observed both at the TF and transcriptome levels.

The dichotomous role of TGF-β in controlling liver cancer cell survival and proliferation

Hepatocellular carcinoma (HCC) is the major form of primary liver cancer and one of the most prevalent and life-threatening malignancies globally. One of the hallmarks in HCC is the sustained cell survival and proliferative signals, which are determined by the balance between oncogenes and tumor suppressors. Transforming growth factor beta (TGF-β) is an effective growth inhibitor of epithelial cells including hepatocytes, through induction of cell cycle arrest, apoptosis, cellular senescence, or autophagy. The antitumorigenic effects of TGF-β are bypassed during liver tumorigenesis via multiple mechanisms. Furthermore, along with malignant progression, TGF-β switches to promote cancer cell survival and proliferation. This dichotomous nature of TGF-β is one of the barriers to therapeutic targeting in liver cancer. Thereafter, understanding the underlying molecular mechanisms is a prerequisite for discovering novel antitumor drugs that may specifically disable the growth-promoting branch of TGF-β signaling or restore its tumor-suppressive arm. This review summarizes how TGF-β inhibits or promotes liver cancer cell survival and proliferation, highlighting the functional switch mechanisms during the process.

Pancreatic Fibroblast Heterogeneity: From Development to Cancer

Pancreatic ductal adenocarcinoma (PDA) is characterized by an extensive fibroinflammatory microenvironment that accumulates from the onset of disease progression. Cancer-associated fibroblasts (CAFs) are a prominent cellular component of the stroma, but their role during carcinogenesis remains controversial, with both tumor-supporting and tumor-restraining functions reported in different studies. One explanation for these contradictory findings is the heterogeneous nature of the fibroblast populations, and the different roles each subset might play in carcinogenesis. Here, we review the current literature on the origin and function of pancreatic fibroblasts, from the developing organ to the healthy adult pancreas, and throughout the initiation and progression of PDA. We also discuss clinical approaches to targeting fibroblasts in PDA.

Physiological Roles of ERM Proteins and Transcriptional Regulators in Supporting Membrane Expression of Efflux Transporters as Factors of Drug Resistance in Cancer

One factor contributing to the malignancy of cancer cells is the acquisition of drug resistance during chemotherapy via increased expression of efflux transporters, such as P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs), and breast cancer resistance protein (BCRP). These transporters operate at the cell membrane, and are anchored in place by the scaffold proteins ezrin (Ezr), radixin (Rdx), and moesin (Msn) (ERM proteins), which regulate their functional activity. The identity of the regulatory scaffold protein(s) differs depending upon the transporter, and also upon the tissue in which it is expressed, even for the same transporter. Another factor contributing to malignancy is metastatic ability. Epithelial-mesenchymal transition (EMT) is the first step in the conversion of primary epithelial cells into mesenchymal cells that can be transported to other organs via the blood. The SNAI family of transcriptional regulators triggers EMT, and SNAI expression is used is an indicator of malignancy. Furthermore, EMT has been suggested to be involved in drug resistance, since drug excretion from cancer cells is promoted during EMT. We showed recently that ERM proteins are induced by a member of the SNAI family, Snail. Here, we first review recent progress in research on the relationship between efflux transporters and scaffold proteins, including the question of tissue specificity. In the second part, we review the relationship between ERM scaffold proteins and the transcriptional regulatory factors that induce their expression.

Identification of metabolism-associated genes and construction of a prognostic signature in bladder cancer

BACKGROUND

Bladder cancer (BC) is a commonly diagnosed malignant tumor in the urinary system, with a high morbidity and a high recurrence rate. Current studies indicated that metabolism-associated genes (MAGs) having critical roles in the etiology of BC. The present study aims to identify differentially expressed MAGs and construct a MAGs based prognostic risk signature for BC by using The Cancer Genome Atlas (TCGA) database and proteomics data.

METHODS

RNA-sequence data from the TCGA database and proteomics data from our BC samples were used to identify differentially expressed MAGs and construct a MAGs based prognostic signature in BC. Subsequently, survival analysis and nomogram were used to evaluate the prognostic and predictive value of the MAGs based signature in BC. RNA isolation and reverse transcription‑quantitative PCR (RT-qPCR) were further performed to investigate the expression levels of MAGs in BC cells and explore the relationship between MAGs and M2 tumor associated macrophages (TAMs) secreted transforming growth factor-β1 (TGF-β1) in BC cells.

RESULTS

A total of 23 differentially expressed MAGs were identified and five MAGs were finally used to construct a MAGs based signature. Survival analysis revealed that the MAGs based signature was closely correlated with the survival outcomes of patients with BC. A nomogram with the MAGs based signature risk score and clinical features was also constructed to facilitate the individualized prediction of BC patients. RT-qPCR showed that five MAGs were significantly differentially expressed and the expression levels of three MAGs were positively correlated with M2 TAMs secreted TGF-β1 in T24 cells.

CONCLUSIONS

Our study identified novel prognostic MAGs and constructed a MAGs based signature, which can be used as an independent factor in evaluating the prognosis of patients with BC. Furthermore, M2 TAMs may promote the expression of MAGs via the TGF-β1 signaling pathway in the microenvironment of BC. Further clinical trials and experimental explorations are needed to validate our observations in BC.

Cytokines in oncolytic virotherapy

Tumors represent a hostile environment for the effector cells of cancer immunosurveillance. Immunosuppressive receptors and soluble or membrane-bound ligands are abundantly exposed and released by malignant entities and their stromal accomplices. As a consequence, executioners of antitumor immunity inefficiently navigate across cancer tissues and fail to eliminate malignant targets. By inducing immunogenic cancer cell death, oncolytic viruses profoundly reshape the tumor microenvironment. They trigger the local spread of danger signals and tumor-associated (as well as viral) antigens, thus attracting antigen-presenting cells, promoting the activation and expansion of lymphocytic populations, facilitating their infiltration in the tumor bed, and reinvigorating cytotoxic immune activity. The present review recapitulates key chemokines, growth factors and other cytokines that orchestrate this ballet of antitumoral leukocytes upon oncolytic virotherapy.

Analysis of the Gene Expression Profile of Stromal Pro-Tumor Factors in Cancer-Associated Fibroblasts from Luminal Breast Carcinomas

Luminal tumors are the most frequent type of breast carcinomas showing less tumor aggressiveness, although heterogeneity exists in their clinical outcomes. Cancer-associated fibroblasts (CAFs) are a key component of the tumor stroma which contribute to tumor progression. We investigated by real-time PCR the gene expression of 19 factors implicated in tumor progression. Those factors included the calcium-binding protein S100A4, several growth factors (FGF2, FGF7, HGF, PDGFA, PDGFB, TGFβ, VEGFA, and IGF2), and we also studied inflammatory cytokines (IL6 and IL8), chemokines (CCL2, CXCL12), important proteases (uPA, MMP2, MMP9 and MMP11), the nuclear factor NFκB, and the metalloprotease inhibitor TIMP1, from luminal A and luminal B breast carcinoma CAFs. We performed a similar analysis after co-culturing CAFs with MCF-7 and MDA-MB-231 breast cancer cell lines. MMP-9 and CCL2 gene expressions were higher in CAFs from luminal B tumors. We also found different patterns in the induction of pro-tumoral factors from different CAFs populations co-cultured with different cancer cell lines. Globally, CAFs from luminal B tumors showed a higher expression of pro-tumor factors compared to CAFs from luminal A tumors when co-cultured with breast cancer cell lines. Moreover, we found that CAFs from metastatic tumors had higher IGF-2 gene expression, and we detected the same after co-culture with cell lines. Our results show the variability in the capacities of CAFs from luminal breast carcinomas, which may contribute to a better biological and clinical characterization of these cancer subtypes.

Roles of TGF-β signaling pathway in tumor microenvirionment and cancer therapy

Transforming growth factor β (TGF- β) signaling pathway has pleiotropic effects on cell proliferation, differentiation, adhesion, senescence, and apoptosis. TGF-β can be widely produced by various immune or non-immune cells and regulate cell behaviors through autocrine and paracrine. It plays essential roles in biological processes including embryological development, immune response, and tumor progression. Few cell signalings can contribute to so many pleiotropic functions as the TGF- β signaling pathway in mammals. The significant function of TGF-β signaling in tumor progression and evasion leading it to draw great attention in scientific and clinical research. Understanding the mechanism of TGF- β signaling provides us with chances to potentiate the effectiveness and selectivity of this therapeutic method. Herein, we review the molecular and cellular mechanisms of TGF-β signaling in carcinomas and tumor microenvironment. Then, we enumerate main achievements of TGF-β blockades used or being evaluated in cancer therapy, providing us opportunities to improve therapeutical approaches in the tumor which thrive in a TGF-β-rich environment.

Crosstalk Between Cancer Associated Fibroblasts and Cancer Cells in Scirrhous Type Gastric Cancer

Gastric cancer (GC) is the third leading cause among all cancer deaths globally. Although the treatment outcome of GC has improved, the survival of patients with GC at stages III and IV remains unsatisfactory. Among several types of GC, scirrhous type GC (SGC) shows highly aggressive growth and invasive activity, leading to frequent peritoneal metastasis. SGC is well known to accompany abundant stromal cells that compose the tumor microenvironment (TME) along with the produced extracellular matrix (ECM) and secreted factors. One of the main stromal components is cancer associated fibroblast (CAF). In the SGC microenvironment, CAFs are a source of various secreted factors, including fibroblast growth factors (FGFs), which mediate prominent tumor-stimulating activity. In turn, cancer cells also secrete numerous factors, which can activate and educate CAFs. Current findings suggest that cancer cells and stromal cells communicate interactively via the soluble factors, the ECM, and likely also by exosomes. In this review, we focus on the soluble factors mediating communication between cancer cells and CAFs in SGC, and consider how they are related to the modulation of TME and the high rate of peritoneal metastasis. At last, we discuss the perspectives on targeting these communication pathways for improved future treatment.

Identification and functional analysis of transforming growth factor-β type III receptor (TβR3) from Scylla paramamosain: The first evidence of TβR3 involved in development and innate immunity in invertebrates

Transforming growth factor-β type III receptor (TβR3), as a co-receptor of TGF-β superfamily, plays critical roles in development and growth as well as some disease pathogeneses by presenting ligands to other receptors in vertebrates. However, the identification and functional characterization of TβR3 had not been reported yet in invertebrates. In the present study, TβR3 was first identified and characterized in mud crab Scylla paramamosain. The obtained cDNA length of SpTβR3 was 2, 424 bp with a 1, 854 bp open reading frame, which encoded a putative peptide of 617 amino acids containing a typical transmembrane region and a Zona pellucida (ZP) domain. Real-time PCR results showed that SpTβR3 was predominantly expressed at early embryonic development stage and early postmolt stage, suggesting its participation in development and growth. We report, for the first time in invertebrates, the challenge of both Vibro alginolyticus and Poly (I:C) could alter the expression patterns of SpTβR3. Notably, the expression levels of SpIKK, two NF-κB members (SpRelish and SpDorsal), and five antimicrobial peptide genes (SpCrustin and SpALF1-4) were significantly suppressed when SpTβR3 was interfered in vivo. Secondly, the overexpression of SpTβR3 in vitro could activate NF-κB signaling through the dual-luciferase reporter assays. Furthermore, the bacterial clearance assay after SpTβR3 was silenced in vivo highlighted the potential of SpTβR3 in activating the innate immune responses. These results implied the involvement of SpTβR3 in the innate immune responses by regulating the NF-κB pathway. This study first indicated that TβR3 was present in invertebrate, and it participated in not only the development and growth but also the innate immunity of S. paramamosain. It also provided new insights into the origin or evolution of TGF-β receptors in crustacean species and even in invertebrates.

Smad7 Enhances TGF-β-Induced Transcription of c-Jun and HDAC6 Promoting Invasion of Prostate Cancer Cells

Transforming growth factor β (TGF-β) enhances migration and invasion of cancer cells, causing life-threatening metastasis. Smad7 expression is induced by TGF-β to control TGF-β signaling in a negative feedback manner. Here we report an additional function of Smad7, i.e., to enhance TGF-β induction of c-Jun and HDAC6 via binding to their regulatory regions, promoting migration and invasion of prostate cancer cells. Lysine 102 in Smad7 is crucial for binding to specific consensus sites in c-Jun and HDAC6, even when endogenous Smad2, 3, and 4 were silenced by siRNA. A correlation between the mRNA expression of Smad7 and HDAC6, Smad7 and c-Jun, and c-Jun and HDAC6 was found in public databases from analyses of prostate cancer tissues. High expression of Smad7, HDAC6, and c-Jun correlated with poor prognosis for patients with prostate cancer. The knowledge that Smad7 can activate transcription of proinvasive genes leading to prostate cancer progression provides clinically relevant information.

Porphyromonas gingivalis promotes progression of esophageal squamous cell cancer via TGFβ-dependent Smad/YAP/TAZ signaling

Microbial dysbiosis in the upper digestive tract is linked to an increased risk of esophageal squamous cell carcinoma (ESCC). Overabundance of Porphyromonas gingivalis is associated with shorter survival of ESCC patients. We investigated the molecular mechanisms driving aggressive progression of ESCC by P. gingivalis. Intracellular invasion of P. gingivalis potentiated proliferation, migration, invasion, and metastasis abilities of ESCC cells via transforming growth factor-β (TGFβ)-dependent Drosophila mothers against decapentaplegic homologs (Smads)/Yes-associated protein (YAP)/Transcriptional coactivator with PDZ-binding motif (TAZ) activation. Smads/YAP/TAZ/TEA domain transcription factor1 (TEAD1) complex formation was essential to initiate downstream target gene expression, inducing an epithelial-mesenchymal transition (EMT) and stemness features. Furthermore, P. gingivalis augmented secretion and bioactivity of TGFβ through glycoprotein A repetitions predominant (GARP) up-regulation. Accordingly, disruption of either the GARP/TGFβ axis or its activated Smads/YAP/TAZ complex abrogated the tumor-promoting role of P. gingivalis. P. gingivalis signature genes based on its activated effector molecules can efficiently distinguish ESCC patients into low- and high-risk groups. Targeting P. gingivalis or its activated effectors may provide novel insights into clinical management of ESCC.

TCR Redirected T Cells for Cancer Treatment: Achievements, Hurdles, and Goals

Adoptive T cell therapy (ACT) is a rapidly evolving therapeutic approach designed to harness T cell specificity and function to fight diseases. Based on the evidence that T lymphocytes can mediate a potent anti-tumor response, initially ACT solely relied on the isolation, in vitro expansion, and infusion of tumor-infiltrating or circulating tumor-specific T cells. Although effective in a subset of cases, in the first ACT clinical trials several patients experienced disease progression, in some cases after temporary disease control. This evidence prompted researchers to improve ACT products by taking advantage of the continuously evolving gene engineering field and by improving manufacturing protocols, to enable the generation of effective and long-term persisting tumor-specific T cell products. Despite recent advances, several challenges, including prioritization of antigen targets, identification, and optimization of tumor-specific T cell receptors, in the development of tools enabling T cells to counteract the immunosuppressive tumor microenvironment, still need to be faced. This review aims at summarizing the major achievements, hurdles and possible solutions designed to improve the ACT efficacy and safety profile in the context of liquid and solid tumors.

Breast Tumor Cell Invasion and Pro-Invasive Activity of Cancer-Associated Fibroblasts Co-Targeted by Novel Urokinase-Derived Decapeptides

Among peritumoral cells, cancer-associated fibroblasts (CAFs) are major facilitators of tumor progression. This study describes the effects of two urokinase-derived, novel decapeptides, denoted as Pep 1 and its cyclic derivative Pep 2. In a mouse model of tumor dissemination, using HT1080 fibrosarcoma cells, Pep 2 reduced the number and size of lung metastases. Specific binding of fluoresceinated Pep 2 to HT1080 and telomerase immortalised fibroblasts (TIF) cell surfaces was enhanced by αv overexpression or abolished by excess vitronectin, anti-αv antibodies or silencing of ITGAV αv gene, identifying αv-integrin as the Pep 2 molecular target. In 3D-organotypic assays, peptide-exposed TIFs and primary CAFs from breast carcinoma patients both exhibited a markedly reduced pro-invasive ability of either HT1080 fibrosarcoma or MDA-MB-231 mammary carcinoma cells, respectively. Furthermore, TIFs, either exposed to Pep 2, or silenced for αv integrin, were impaired in their ability to chemoattract cancer cells and to contract collagen matrices, exhibiting reduced α-smooth muscle actin (α-SMA) levels. Finally, peptide exposure of αv-expressing primary CAFs led to the downregulation of α-SMA protein and to a dramatic reduction of their pro-invasive capability. In conclusion, the ability of the novel decapeptides to interfere with tumor cell invasion directly and through the down-modulation of CAF phenotype suggests their use as lead compounds for co-targeting anti-cancer strategies.

The RNA Binding Protein HuR: A Promising Drug Target for Anticancer Therapy

The stability of mRNA is one of the key factors governing the regulation of eukaryotic gene expression and function. Human antigen R (HuR) is an RNA-binding protein that regulates the stability, translation, and nucleus-to-cytoplasm shuttling of its target mRNAs. While HuR is normally localized within the nucleus, it has been shown that HuR binds mRNAs in the nucleus and then escorts the mRNAs to the cytoplasm where HuR protects them from degradation. It contains several RNA recognition motifs, which specifically bind to adenylate and uridylate-rich regions within the 3'-untranslated region of the target mRNA to mediate its effect. Many of the HuR target mRNAs encode proteins important for cell growth, tumorigenesis, angiogenesis, tumor inflammation, invasion and metastasis. HuR overexpression is known to correlate well with high-grade malignancy and poor prognosis in many tumor types. Thus, HuR has emerged as an attractive drug target for cancer therapy. Novel small molecule HuR inhibitors have been identified by high throughput screening and new formulations for targeted delivery of HuR siRNA to tumor cells have been developed with promising anticancer activity. This review summarizes the significant role of HuR in cancer development, progression, and poor treatment response. We will discuss the potential and challenges of targeting HuR therapeutically.

C1222C Deletion in Exon 8 of ABL1 Is Involved in Carcinogenesis and Cell Cycle Control of Colorectal Cancer Through IRS1/PI3K/Akt Pathway

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide. ABL1 (c-Abl) is a non-receptor tyrosine kinase, whose role, and molecular mechanism in CRC remain largely unclear. The aim of this study was to elucidate the role of ABL1 to obtain information on colon cancer gene mutation. We analyzed the tissue samples obtained from patients with CRC, CRC cell lines, and the immunodeficient mice. The proliferation, cell cycle, and apoptosis of CRC cells were examined. IPA software was used to analyze the molecules involved in CRC after ABL1 RNA interference. We found ABL1 was highly expressed in CRC tissues and cells. This high expression was associated with the TNM stage of CRC patients. In exon 8 of the ABL1 gene, we identified a novel mutation of C1222C deletion, which was related to the CRC stage. Depletion of ABL1 resulted in the inhibition of proliferation and escalation of apoptosis in two CRC cell lines, SW480, and HCT-116. Our in vivo study also demonstrated that depletion of ABL1 reduced CRC tumor progression. The results of the ingenuity pathway analysis indicated that the expression of 732 genes was upregulated and that of 691 genes was downregulated in mice transplanted with ABL1-downregulated CRC cells, among which we confirmed that depletion of ABL1 inhibited TGF-β1 via IRS1/PI3K/AKT pathway in CRC progression. These findings demonstrated that ABL1 plays an important role and that it can be a potential molecular target for CRC therapy.

Cancer-Derived Transforming Growth Factor-β Modulates Tumor-Associated Macrophages in Ampullary Cancer

Purpose

Tumor-associated macrophages (TAMs) originate from monocytes and differentiate into mature macrophages. The interaction between cancer cells and TAMs promotes tumor growth and suppresses immunosurveillance. However, this phenomenon has seldom been observed in ampullary cancer.

Patients and Methods

TAMs in ampullary cancer were investigated using immunohistochemical (IHC) staining of cancer tissues. Bioinformatic analysis of data from the Gene Expression Omnibus (GEO) database revealed transforming growth factor-beta (TGF-β) signaling in ampullary cancer. The complementary DNA microarray of cancer was compared with adjacent normal duodenum and enzyme-linked immunosorbent assay of serum was used to verify TGF-β signaling in patients. The THP-1 cell line was activated in vitro to imitate M2 TAMs. ClueGo and CluePedia software were operated to simulate TGF-β-related networks in ampullary cancer.

Results

The IHC study revealed that the majority of TAMs inside ampullary cancer were cluster of differentiation (CD)163⁺ cells and that the expression of mature CD68⁺ macrophages was correlated with advanced cancer stage. Bioinformatics analysis revealed that TGF-β and its downstream signaling were significantly upregulated. To verify our bioinformatics-derived predictions, we performed several experiments and demonstrated that increased TGF-β expression was detected in the cDNA microarray. Higher serum levels of TGF-β were correlated with fewer CD68⁺ and more inducible nitric oxide synthase macrophages in ampullary cancer. Treatment with TGF-β induced modulation of THP-1-derived macrophages.

Conclusion

The present study demonstrates that TGF-β modulates macrophage activity in ampullary cancer. Targeting TGF-β could be an approach to activating immunosurveillance.