GPER is a mechanoregulator of pancreatic stellate cells and the tumor microenvironment

Immune cell distribution and DNA methylation signatures differ between tumor and stroma enriched compartment in pancreatic ductal adenocarcinoma

The presence of abundant tumor stroma is a prominent characteristic of pancreatic ductal adenocarcinomas (PDAC) that potentially influences disease progression and therapy response. This study aims to investigate immune cell infiltration and epigenetic profiles in tumor cell enriched ("Tumor") and stroma cell enriched ("Stroma") regions within human PDAC tissue samples. By comparing those regions, we identified 25,410 differentially methylated positions (DMPs) distributed across 6,963 unique genes. Pathway enrichment analysis using the top 2,000 DMPs that were either hyper- or hypomethylated indicated that immune response pathways and the estrogen receptor pathway are epigenetically dysregulated in Tumor and Stroma regions, respectively. In terms of immune cell infiltration, we observed overall low levels of T cells in both regions. In Tumor regions however, occurrence of tumor-associated macrophages (TAMs) was higher than in Stroma regions (p = 0.02) concomitant with a dualistic distribution that stratifies PDAC patients into those with high and low TAM infiltration. By categorizing TAM levels into quartiles, our analysis revealed that PDAC patients with more than 1,515 TAMs per mm² exhibited significantly shorter overall survival (p = 0.036). Our data suggest that variations in inflammatory characteristics between the Tumor and Stroma defined compartments of PDAC may primarily stem from the presence of macrophages rather than lymphocytes. The abundance of TAMs within regions enriched with tumor cells correlates with patient survival, underscoring the potential significance of exploring therapeutic interventions targeting TAMs. Furthermore, directing attention towards the estrogen receptor pathway may represent a promising strategy to address the stroma cell component within the PDAC tumor microenvironment.

Advances in immune regulation of the G protein-coupled estrogen receptor

Estrogen and related receptors have been shown to have a significant impact on human development, reproduction, metabolism and immune regulation and to play a critical role in tumor development and treatment. Traditionally, the nuclear estrogen receptors (nERs) ERα and ERβ have been thought to be involved in mediating the estrogenic effects. However, our group and others have previously demonstrated that the G protein-coupled estrogen receptor (GPER) is the third independent ER, and estrogen signaling mediated by GPER is known to play an important role in normal physiology and a variety of abnormal diseases. Interestingly, recent studies have progressively revealed GPER involvement in the maintenance of the normal immune system, abnormal immune diseases, and inflammatory lesions, which may be of significant clinical value primarily in the immunotherapy of tumors. In this article, we review current advances in GPER-related immunomodulators and provide a theoretical basis and potential clinical targets to ameliorate immune-related diseases and immunotherapy for tumors.

YAP-mediated GPER signaling impedes proliferation and survival of prostate epithelium in benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) occurs when there is an imbalance between the proliferation and death of prostate cells, which is regulated tightly by estrogen signaling. However, the role of G protein-coupled estrogen receptor (GPER) in prostate cell survival remains ambiguous. In this study, we observed that prostates with epithelial hyperplasia showed increased yes-associated protein 1 (YAP) expression and decreased levels of estrogen and GPER. Blocking YAP through genetic or drug interventions led to reduced proliferation and increased apoptosis in the prostate epithelial cells. Interestingly, GPER agonists produced similar effects. GPER activation enhanced the phosphorylation and degradation of YAP, which was crucial for suppressing cell proliferation and survival. The Gαs/cAMP/PKA/LATS pathway, downstream of GPER, transmitted signals that facilitated YAP inhibition. This study investigated the interaction between GPER and YAP in the prostate epithelial cells and its contribution to BPH development. It lays the groundwork for future research on developing BPH treatments.

GPER involvement in inflammatory pain

Chronic pain is a worldwide refractory health disease that causes major financial and emotional burdens and that is devastating for individuals and society. One primary source of pain is inflammation. Current treatments for inflammatory pain are weakly effective, although they usually replace analgesics, such as opioids and non-steroidal anti-inflammatory drugs, which display serious side effects. Emerging evidence indicates that the membrane G protein-coupled estrogen receptor (GPER) may play an important role in the regulation of inflammation and pain. Herein, we focus on the consequences of pharmacological and genetic GPER modulation in different animal models of inflammatory pain. We also provide a brief overview of the putative mechanisms including the direct action of GPER on pain transmission and inflammation.

Integration of Chemo-mechanical signaling in response to fluid shear stress by the endothelium

Physical forces exert profound effects on cells affecting fate, function, and response to stressors. In the case of the endothelium, the layer that resides in the inner surface of blood vessels, the collective effect of hemodynamic forces influences the onset and severity of vascular pathologies. Justifiably, much emphasis has been placed in understanding how endothelial cells sense and respond to mechanical challenges, particularly hemodynamic shear stress. In this review, we highlight recent developments that have expanded our understanding of the molecular mechanisms underlying mechanotransduction. We describe examples of protein compartmentalization in response to shear stress, consider the contribution of the glycocalyx, and discuss the specific role ion channels in response to flow. We also highlight the recently recognized contribution of the receptor ALK5 in sensing turbulent flow. Research in the last three years has enriched our understanding of the molecular landscape responsible for recognizing and transducing shear stress responses, including novel transcriptional-dependent and transcriptional-independent mechanisms.

Utility of G protein-coupled oestrogen receptor 1 as a biomarker for pan-cancer diagnosis, prognosis and immune infiltration: a comprehensive bioinformatics analysis

BACKGROUND

The G protein-coupled oestrogen receptor (GPER) 1 mediates non-genomic oestrogen-related signalling and plays an important role in the regulation of cell growth and programmed cell death through multiple downstream pathways. Despite the increasing interest in the role of GPER1 in cancer development, no pan-cancer analysis has been available for GPER1.

METHODS

In this study we performed a comprehensive analysis of the role of GPER1 in pan-cancer via Human Protein Atlas (HPA), The Cancer Genome Atlas (TCGA), University of California, Santa Cruz Xena (UCSC XENA), Genotype-Tissue Expression (GTEx), MethSurv, The University of Alabama at Birmingham CANcer data analysis Portal (UALCAN), cBioPortal, STRING and TISIDB detabases, followed by enrichment analysis using R software.

RESULTS

GPER1 was widely expressed in tissues and organs and differed in expression from normal tissue in a variety of cancers. In diagnostic assessment, it's Area Under the Curve (AUC) surpassed 0.9 in nine cancer types. Survival analysis showed that GPER1 was correlated with the prognosis of 11 cancer types. Moreover, GPER1 expression was associated with immune infiltration in multiple cancers.

CONCLUSIONS

In summary, GPER1 has good diagnostic or prognostic value across various malignancies. Together with its extensive correlation with immune components, the aforementioned results suggests that GPER1 shows promise in tumour diagnosis and prognosis, providing new ideas for precise and personalised anti-tumour strategies.

Repurposing Tamoxifen for Tumor Microenvironment Priming and Enhanced Tumor-Targeted Drug Delivery

The dense stromal matrix in fibrotic tumors hinders tumor-targeted drug delivery. Tamoxifen (TMX), an estrogen receptor modulator that is clinically used for the treatment of breast cancer, has been shown to reprogram the tumor microenvironment (TME) and to alleviate desmoplasia. We here investigated if TMX, administered in free and nano-formulated form, can be repurposed as a TME remodeling agent to improve tumor accumulation of nano-formulations in pancreatic ductal adenocarcinoma and triple-negative breast cancer mouse models, evaluated using clinical-stage Cy7-labeled core-crosslinked polymeric micelles (CCPM). Under control conditions, we found higher levels of Cy7-CCPM in PANC-1 tumors (16.7 % ID g-1 at 48 h post i.v. injection) than in 4T1 tumors (11.0 % ID g-1). In both models, free and nano-formulated TMX failed to improve CCPM delivery. These findings were congruent with the results from histopathological immunofluorescence analysis of tumor tissue, which indicated that TMX treatment did not significantly change vascularization, perfusion, macrophage infiltration, collagen density, and collagen fiber thickness. Altogether, our results demonstrate that in PANC-1 and 4T1 mouse models, TMX treatment does not contribute to beneficial TME priming and enhanced tumor-targeted drug delivery.

Biophysics in tumor growth and progression: from single mechano-sensitive molecules to mechanomedicine

Evidence from physical sciences in oncology increasingly suggests that the interplay between the biophysical tumor microenvironment and genetic regulation has significant impact on tumor progression. Especially, tumor cells and the associated stromal cells not only alter their own cytoskeleton and physical properties but also remodel the microenvironment with anomalous physical properties. Together, these altered mechano-omics of tumor tissues and their constituents fundamentally shift the mechanotransduction paradigms in tumorous and stromal cells and activate oncogenic signaling within the neoplastic niche to facilitate tumor progression. However, current findings on tumor biophysics are limited, scattered, and often contradictory in multiple contexts. Systematic understanding of how biophysical cues influence tumor pathophysiology is still lacking. This review discusses recent different schools of findings in tumor biophysics that have arisen from multi-scale mechanobiology and the cutting-edge technologies. These findings range from the molecular and cellular to the whole tissue level and feature functional crosstalk between mechanotransduction and oncogenic signaling. We highlight the potential of these anomalous physical alterations as new therapeutic targets for cancer mechanomedicine. This framework reconciles opposing opinions in the field, proposes new directions for future cancer research, and conceptualizes novel mechanomedicine landscape to overcome the inherent shortcomings of conventional cancer diagnosis and therapies.

GPER: An Estrogen Receptor Key in Metastasis and Tumoral Microenvironments

Estrogens and their role in cancer are well-studied, and some cancer types are classified in terms of their response to them. In recent years, a G protein-coupled estrogen receptor (GPER) has been described with relevance in cancer. GPER is a pleiotropic receptor with tissue-specific activity; in normal tissues, its activation is related to correct development and homeostasis, while in cancer cells, it can be pro- or anti-tumorigenic. Also, GPER replaces estrogen responsiveness in estrogen receptor alpha (ERα)-lacking cancer cell lines. One of the most outstanding activities of GPER is its role in epithelial-mesenchymal transition (EMT), which is relevant for metastasis development. In addition, the presence of this receptor in tumor microenvironment cells contributes to the phenotypic plasticity required for the dissemination and maintenance of tumors. These characteristics suggest that GPER could be a promising therapeutic target for regulating cancer development. This review focuses on the role of GPER in EMT in tumorigenic and associated cells, highlighting its role in relation to the main hallmarks of cancer and possible therapeutic options.

Pancreatic stellate cells in pancreatic cancer: as potential targets for future therapy

Pancreatic cancer is a strongly malignant gastrointestinal carcinoma characterized by late detection, high mortality rates, poor patient prognosis and lack of effective treatments. Consequently, there is an urgent need to identify novel therapeutic strategies for this disease. Pancreatic stellate cells, which constitute a significant component of the mesenchymal cellular layer within the pancreatic tumor microenvironment, play a pivotal role in modulating this environment through their interactions with pancreatic cancer cells. This paper reviews the mechanisms by which pancreatic stellate cells inhibit antitumor immune responses and promote cancer progression. We also discuss preclinical studies focusing on these cells, with the goal of providing some theoretical references for the development of new therapeutic approaches for pancreatic cancer.

The G protein-coupled oestrogen receptor GPER in health and disease: an update

Oestrogens and their receptors contribute broadly to physiology and diseases. In premenopausal women, endogenous oestrogens protect against cardiovascular, metabolic and neurological diseases and are involved in hormone-sensitive cancers such as breast cancer. Oestrogens and oestrogen mimetics mediate their effects via the cytosolic and nuclear receptors oestrogen receptor-α (ERα) and oestrogen receptor-β (ERβ) and membrane subpopulations as well as the 7-transmembrane G protein-coupled oestrogen receptor (GPER). GPER, which dates back more than 450 million years in evolution, mediates both rapid signalling and transcriptional regulation. Oestrogen mimetics (such as phytooestrogens and xenooestrogens including endocrine disruptors) and licensed drugs such as selective oestrogen receptor modulators (SERMs) and downregulators (SERDs) also modulate oestrogen receptor activity in both health and disease. Following up on our previous Review of 2011, we herein summarize the progress made in the field of GPER research over the past decade. We will review molecular, cellular and pharmacological aspects of GPER signalling and function, its contribution to physiology, health and disease, and the potential of GPER to serve as a therapeutic target and prognostic indicator of numerous diseases. We also discuss the first clinical trial evaluating a GPER-selective drug and the opportunity of repurposing licensed drugs for the targeting of GPER in clinical medicine.

A Quick Guide to CAF Subtypes in Pancreatic Cancer

Pancreatic cancer represents one of the most desmoplastic malignancies and is characterized by an extensive deposition of extracellular matrix. The latter is provided by activated cancer-associated fibroblasts (CAFs), which are abundant cells in the pancreatic tumor microenvironment. Many recent studies have made it clear that CAFs are not a singular cellular entity but represent a multitude of potentially dynamic subgroups that affect tumor biology at several levels. As mentioned before, CAFs significantly contribute to the fibrotic reaction and the biomechanical properties of the tumor, but they can also modulate the local immune environment and the response to targeted, chemo or radiotherapy. As the number of known and emerging CAF subgroups is steadily increasing, it is becoming increasingly difficult to keep up with these developments and to clearly discriminate the cellular subsets identified so far. This review aims to provide a helpful overview that enables readers to quickly familiarize themselves with field of CAF heterogeneity and to grasp the phenotypic, functional and therapeutic distinctions of the various stromal subpopulations.

Retinoic acid receptor β modulates mechanosensing and invasion in pancreatic cancer cells via myosin light chain 2

Pancreatic ductal adenocarcinoma (PDAC) is the most common and lethal form of pancreatic cancer, characterised by stromal remodelling, elevated matrix stiffness and high metastatic rate. Retinoids, compounds derived from vitamin A, have a history of clinical use in cancer for their anti-proliferative and differentiation effects, and more recently have been explored as anti-stromal therapies in PDAC for their ability to induce mechanical quiescence in cancer associated fibroblasts. Here, we demonstrate that retinoic acid receptor β (RAR-β) transcriptionally represses myosin light chain 2 (MLC-2) expression in pancreatic cancer cells. As a key regulatory component of the contractile actomyosin machinery, MLC-2 downregulation results in decreased cytoskeletal stiffness and traction force generation, impaired response to mechanical stimuli via mechanosensing and reduced ability to invade through the basement membrane. This work highlights the potential of retinoids to target the mechanical drivers of pancreatic cancer.

Mechanisms of obesity- and diabetes mellitus-related pancreatic carcinogenesis: a comprehensive and systematic review

Research on obesity- and diabetes mellitus (DM)-related carcinogenesis has expanded exponentially since these two diseases were recognized as important risk factors for cancers. The growing interest in this area is prominently actuated by the increasing obesity and DM prevalence, which is partially responsible for the slight but constant increase in pancreatic cancer (PC) occurrence. PC is a highly lethal malignancy characterized by its insidious symptoms, delayed diagnosis, and devastating prognosis. The intricate process of obesity and DM promoting pancreatic carcinogenesis involves their local impact on the pancreas and concurrent whole-body systemic changes that are suitable for cancer initiation. The main mechanisms involved in this process include the excessive accumulation of various nutrients and metabolites promoting carcinogenesis directly while also aggravating mutagenic and carcinogenic metabolic disorders by affecting multiple pathways. Detrimental alterations in gastrointestinal and sex hormone levels and microbiome dysfunction further compromise immunometabolic regulation and contribute to the establishment of an immunosuppressive tumor microenvironment (TME) for carcinogenesis, which can be exacerbated by several crucial pathophysiological processes and TME components, such as autophagy, endoplasmic reticulum stress, oxidative stress, epithelial-mesenchymal transition, and exosome secretion. This review provides a comprehensive and critical analysis of the immunometabolic mechanisms of obesity- and DM-related pancreatic carcinogenesis and dissects how metabolic disorders impair anticancer immunity and influence pathophysiological processes to favor cancer initiation.

Characterization of Estrogen Receptors in Pancreatic Adenocarcinoma with Tertiary Lymphoid Structures

The role of estrogen signaling in antitumor immunology remains unknown for non-traditional sex-biased cancer types such as pancreatic adenocarcinoma (PAAD). Tertiary lymphoid structures (TLS) are active zones composed of multiple types of immune cells, whose presence indicates anti-tumor immune responses. In this study, we employed a 12-chemokine signature to characterize potential gene categories associated with TLS development and identified seventeen major gene categories including estrogen receptors (ERs). Immunohistochemistry staining revealed the expression patterns of three ERs (ERα, ERβ, and GPER) in 174 PAAD samples, and their correlation with clinicopathological characteristics, immune cell infiltration levels, and intratumoral TLS presence was analyzed. The results indicated that ERα (+) and ERβ (+) were correlated with high tumor grade, and ERβ (+) and GPER (+) were correlated with lower TNM stage, and both ERα (+) and GPER (+) displayed a beneficial effect on prognosis in this cohort. Interestingly, positive staining of all three ERs was significantly correlated with the presence of intratumoral TLSs and infiltration of more active immune cells into the microenvironment. Moreover, the chemotaxis of CD8⁺T-cells to PAAD cells was significantly increased in vitro with upregulated expression of ERα or ERβ on PAAD cells. To conclude, our study showed a novel correlation between ER expression and TLS development, suggesting that ERs may play a protective role by enhancing anti-tumor immune responses in PAAD.

Heterogeneous cancer-associated fibroblasts: A new perspective for understanding immunosuppression in pancreatic cancer

Immunotherapy has shown promising efficacy in the treatment of a wide range of cancers; however, it has had little effect on pancreatic cancer. Cancer-associated fibroblasts (CAFs), the predominant mesenchymal cells present in the pancreatic cancer microenvironment, are powerful supporters of the malignant progression of pancreatic cancer. CAFs can modify the microenvironment, establish a refuge to aid cancer cells in immune escape by secreting large amounts of extracellular matrix, and produce soluble cytokines and exosomal vesicles. Hence, CAFs are important contributors to the failure of immunotherapy. Current in-depth studies of CAFs have shown that CAFs are a heterogeneous population of mesenchymal cells; therefore, the functional complexity of their populations needs in-depth explorations in future studies. This review summarizes how heterogeneous CAFs help cancer cells achieve immune escape and suggests potential directions for using CAFs as targets to address immune escape.

Mechanobiology of Colorectal Cancer

In this review, the mechanobiology of colorectal cancer (CRC) are discussed. Mechanotransduction of CRC is addressed considering the relationship of several biophysical cues and biochemical pathways. Mechanobiology is focused on considering how it may influence epithelial cells in terms of motility, morphometric changes, intravasation, circulation, extravasation, and metastization in CRC development. The roles of the tumor microenvironment, ECM, and stroma are also discussed, taking into account the influence of alterations and surface modifications on mechanical properties and their impact on epithelial cells and CRC progression. The role of cancer-associated fibroblasts and the impact of flow shear stress is addressed in terms of how it affects CRC metastization. Finally, some insights concerning how the knowledge of biophysical mechanisms may contribute to the development of new therapeutic strategies and targeting molecules and how mechanical changes of the microenvironment play a role in CRC disease are presented.

Substrate Stiffness-Driven Membrane Tension Modulates Vesicular Trafficking via Caveolin-1

Liver fibrosis, a condition characterized by extensive deposition and cross-linking of extracellular matrix (ECM) proteins, is idiosyncratic in cases of chronic liver injury. The dysregulation of ECM remodeling by hepatic stellate cells (HSCs), the main mediators of fibrosis, results in an elevated ECM stiffness that drives the development of chronic liver disease such as cirrhosis and hepatocellular carcinoma. Tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) is a key element in the regulation of ECM remodeling, which modulates the degradation and turnover of ECM components. We have previously reported that a rigid, fibrotic-like substrate can impact TIMP-1 expression at the protein level in HSCs without altering its mRNA expression. While HSCs are known to be highly susceptible to mechanical stimuli, the mechanisms through which mechanical cues regulate TIMP-1 at the post-translational level remain unclear. Here, we show a mechanism of regulation of plasma membrane tension by matrix stiffness. We found that this effect is orchestrated by the β1 integrin/RhoA axis and results in elevated exocytosis and secretion of TIMP-1 in a caveolin-1- and dynamin-2-dependent manner. We then show that TIMP-1 and caveolin-1 expression increases in cirrhosis and hepatocellular carcinoma. These conditions are associated with fibrosis, and this effect can be recapitulated in 3D fibrosis models consisting of hepatic stellate cells encapsulated in a self-assembling polypeptide hydrogel. This work positions stiffness-dependent membrane tension as a key regulator of enzyme secretion and function and a potential target for therapeutic strategies that aim at modulating ECM remodeling in chronic liver disease.

Loss of LAT1 sex-dependently delays recovery after caerulein-induced acute pancreatitis

BACKGROUND

The expression of amino acid transporters is known to vary during acute pancreatitis (AP) except for LAT1 (slc7a5), the expression of which remains stable. LAT1 supports cell growth by importing leucine and thereby stimulates mammalian target of rapamycin (mTOR) activity, a phenomenon often observed in cancer cells. The mechanisms by which LAT1 influences physiological and pathophysiological processes and affects disease progression in the pancreas are not yet known.

AIM

To evaluate the role of LAT1 in the development of and recovery from AP.

METHODS

AP was induced with caerulein (cae) injections in female and male mice expressing LAT1 or after its knockout (LAT1 Cre/LoxP). The development of the initial AP injury and its recovery were followed for seven days after cae injections by daily measuring body weight, assessing microscopical tissue architecture, mRNA and protein expression, protein synthesis, and enzyme activity levels, as well as by testing the recruitment of immune cells by FACS and ELISA.

RESULTS

The initial injury, evaluated by measurements of plasma amylase, lipase, and trypsin activity, as well as the gene expression of dedifferentiation markers, did not differ between the groups. However, early metabolic adaptations that support regeneration at later stages were blunted in LAT1 knockout mice. Especially in females, we observed less mTOR reactivation and dysfunctional autophagy. The later regeneration phase was clearly delayed in female LAT1 knockout mice, which did not regain normal expression of the pancreas-specific differentiation markers recombining binding protein suppressor of hairless-like protein (rbpjl) and basic helix-loop-helix family member A15 (mist1). Amylase mRNA and protein levels remained lower, and, strikingly, female LAT1 knockout mice presented signs of fibrosis lasting until day seven. In contrast, pancreas morphology had returned to normal in wild-type littermates.

CONCLUSION

LAT1 supports the regeneration of acinar cells after AP. Female mice lacking LAT1 exhibited more pronounced alterations than male mice, indicating a sexual dimorphism of amino acid metabolism.

A review of the functions of G protein-coupled estrogen receptor 1 in vascular and neurological aging

Aging-related diseases, especially vascular and neurological disorders cause huge economic burden. How to delay vascular and neurological aging is one of the insurmountable questions. G protein-coupled estrogen receptor 1 (GPER) has been extensively investigated in recent years due to its multiple biological responses. In this review, the function of GPER in aging-related diseases represented by vascular diseases, and neurological disorders were discussed. Apart from that, activation of GPER was also found to renovate the aging brain characterized by memory decline, but in a manner different from another two nuclear estrogen receptors estrogen receptor (ER)α and ERβ. This salutary effect would be better clarified from the aspects of synaptic inputs and transmission. Furthermore, we carefully described molecular mechanisms underpinning GPER-mediated effects. This review would update our understanding of GPER in the aging process. Targeting GPER may represent a promising strategy in the aging-related disorders.

Repositioning of duloxetine to target pancreatic stellate cells

Pancreatic cancer cells (PCCs) are surrounded by an abundant stroma, which is produced by pancreatic stellate cells (PSCs). PSCs promote tumor cell proliferation and invasion. The objective of the current study was to identify compounds that suppress PSC activation. Gene expression profiles of cancer-derived fibroblasts and normal fibroblasts were used, and the pathway analysis suggested altered pathways that were chosen for validation. It was found that the ‘neuroactive ligand-receptor interaction’ pathway from the Kyoto Encyclopedia of Genes and Genomes pathway analysis was one of the altered pathways. Several compounds related with this pathway were chosen, and changes in PSC activity were investigated using fluorescence staining of lipid droplets, reverse transcription-quantitative PCR, western blotting, and invasion and migration assays. Among these candidates, duloxetine, a serotonin-noradrenaline reuptake inhibitor, was found to suppress PSC activation and disrupt tumor-stromal interaction. Thus, duloxetine may be a potential drug for suppressing PSC activation and pancreatic cancer growth.

Endogenous and Therapeutic Estrogens: Maestro Conductors of the Microenvironment of ER+ Breast Cancers

Estrogen receptor alpha (ERα) marks heterogeneous breast cancers which display a repertoire of somatic genomic mutations and an immune environment that differs from other breast cancer subtypes. These cancers also exhibit distinct biological behaviors; despite an overall better prognosis than HER2+ or triple negative breast cancers, disseminated dormant cells can lead to disease recurrence decades after the initial diagnosis and treatment. Estrogen is the best studied driver of these cancers, and antagonism or reduction of estrogen activity is the cornerstone of therapeutic approaches. In addition to reducing proliferation of ERα+ cancer cells, these treatments also alter signals to multiple other target cells in the environment, including immune cell subpopulations, cancer-associated fibroblasts, and endothelial cells via several distinct estrogen receptors. In this review, we update progress in our understanding of the stromal cells populating the microenvironments of primary and metastatic ER+ tumors, the effects of estrogen on tumor and stromal cells to modulate immune activity and the extracellular matrix, and net outcomes in experimental and clinical studies. We highlight new approaches that will illuminate the unique biology of these cancers, provide the foundation for developing new treatment and prevention strategies, and reduce mortality of this disease.

New high-throughput screening detects compounds that suppress pancreatic stellate cell activation and attenuate pancreatic cancer growth

BACKGROUND/OBJECTIVES

Pancreatic stellate cells (PSCs) are involved in abundant desmoplasia, which promotes cancer cell aggressiveness and resistance to anti-cancer drugs. Therefore, PSCs are suggested to be a promising therapeutic target by attenuating PSC activation to inhibit tumor-stromal interactions with pancreatic cancer cells. Here, we developed a screen to identify compounds that reduce the activity of PSCs and investigated the effect of candidates on pancreatic cancer.

METHODS

Lipid droplet accumulation in PSCs was used to observe differences in PSC activity and a new high-throughput screening platform that quantified lipid droplets in PSCs was established. A library of 3398 Food and Drug Administration-approved drugs was screened by this platform. Validation assays were performed in vitro and in vivo.

RESULTS

Thirty-two compounds were finally selected as candidate compounds by screening. These compounds decreased α-smooth muscle actin expression and inhibited autophagic flux in PSCs in vitro. Among the candidates, three drugs selected for validation assays inhibited the proliferation and migration of PSCs and invasion of cancer cells by disrupting tumor-stromal interactions. Production of extracellular matrix molecules was also decreased significantly by this treatment. In vivo testing in xenograft models showed that dopamine antagonist zuclopenthixol suppressed tumor growth; this suppression was significantly increased when combined with gemcitabine.

CONCLUSIONS

A new screening platform that focused on the morphological features of PSCs was developed. Candidate drugs from this screening suppressed PSC activation and tumor growth. This screening system may be useful to discover new compounds that attenuate PSC activation.

Role of G Protein-Coupled Estrogen Receptor in Digestive System Carcinomas: A Minireview

Digestive system carcinomas are one of the leading causes of cancer-related deaths worldwide. G protein-coupled estrogen receptor (GPER), a novel estrogen receptor, has been recognized as an important mediator in numerous cancer types. Recently, the function and clinical significance of GPER in digestive system carcinomas has been a subject of interest. Increasing evidence has revealed that GPER plays an important role as a potential biomarker in digestive system carcinomas. This work summarizes the recent literature and focuses on the emerging functional role of GPER in digestive system carcinomas, including gastric cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer. The potential application of GPER in novel strategies for the diagnosis and treatment of digestive system carcinomas is discussed and highlighted.

Dissecting FGF Signalling to Target Cellular Crosstalk in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with a 5 year survival rate of less than 8%, and is predicted to become the second leading cause of cancer-related death by 2030. Alongside late detection, which impacts upon surgical treatment, PDAC tumours are challenging to treat due to their desmoplastic stroma and hypovascular nature, which limits the effectiveness of chemotherapy and radiotherapy. Pancreatic stellate cells (PSCs), which form a key part of this stroma, become activated in response to tumour development, entering into cross-talk with cancer cells to induce tumour cell proliferation and invasion, leading to metastatic spread. We and others have shown that Fibroblast Growth Factor Receptor (FGFR) signalling can play a critical role in the interactions between PDAC cells and the tumour microenvironment, but it is clear that the FGFR signalling pathway is not acting in isolation. Here we describe our current understanding of the mechanisms by which FGFR signalling contributes to PDAC progression, focusing on its interaction with other pathways in signalling networks and discussing the therapeutic approaches that are being developed to try and improve prognosis for this terrible disease.

New Roles for Vitamin D Superagonists: From COVID to Cancer

Vitamin D is a potent steroid hormone that induces widespread changes in gene expression and controls key biological pathways. Here we review pathophysiology of vitamin D with particular reference to COVID-19 and pancreatic cancer. Utility as a therapeutic agent is limited by hypercalcemic effects and attempts to circumvent this problem have used vitamin D superagonists, with increased efficacy and reduced calcemic effect. A further caveat is that vitamin D mediates multiple diverse effects. Some of these (anti-fibrosis) are likely beneficial in patients with COVID-19 and pancreatic cancer, whereas others (reduced immunity), may be beneficial through attenuation of the cytokine storm in patients with advanced COVID-19, but detrimental in pancreatic cancer. Vitamin D superagonists represent an untapped resource for development of effective therapeutic agents. However, to be successful this approach will require agonists with high cell-tissue specificity.

The Role of Stellate Cells in Pancreatic Ductal Adenocarcinoma: Targeting Perspectives

Pancreatic ductal adenocarcinoma (PDAC) is a gastrointestinal malignancy with a dismal clinical outcome. Accumulating evidence suggests that activated pancreatic stellate cells (PSCs), the major producers of extracellular matrix (ECM), drive the severe stromal/desmoplastic reaction in PDAC. Furthermore, the crosstalk among PSCs, pancreatic cancer cells (PCCs) as well as other stroma cells can establish a growth-supportive tumor microenvironment (TME) of PDAC, thereby enhancing tumor growth, metastasis, and chemoresistance via various pathways. Recently, targeting stroma has emerged as a promising strategy for PDAC therapy, and several novel strategies have been proposed. The aim of our study is to give a profound review of the role of PSCs in PDAC progression and recent advances in stroma-targeting strategies.

Modifications on the Tetrahydroquinoline Scaffold Targeting a Phenylalanine Cluster on GPER as Antiproliferative Compounds against Renal, Liver and Pancreatic Cancer Cells

The implementation of chemo- and bioinformatics tools is a crucial step in the design of structure-based drugs, enabling the identification of more specific and effective molecules against cancer without side effects. In this study, three new compounds were designed and synthesized with suitable absorption, distribution, metabolism, excretion and toxicity (ADME-tox) properties and high affinity for the G protein-coupled estrogen receptor (GPER) binding site by in silico methods, which correlated with the growth inhibitory activity tested in a cluster of cancer cell lines. Docking and molecular dynamics (MD) simulations accompanied by a molecular mechanics/generalized Born surface area (MMGBSA) approach yielded the binding modes and energetic features of the proposed compounds on GPER. These in silico studies showed that the compounds reached the GPER binding site, establishing interactions with a phenylalanine cluster (F206, F208 and F278) required for GPER molecular recognition of its agonist and antagonist ligands. Finally, a 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay showed growth inhibitory activity of compounds 4, 5 and 7 in three different cancer cell lines-MIA Paca-2, RCC4-VA and Hep G2-at micromolar concentrations. These new molecules with specific chemical modifications of the GPER pharmacophore open up the possibility of generating new compounds capable of reaching the GPER binding site with potential growth inhibitory activities against nonconventional GPER cell models.

Diversity and Biology of Cancer-Associated Fibroblasts

Efforts to develop anti-cancer therapies have largely focused on targeting the epithelial compartment, despite the presence of non-neoplastic stromal components that substantially contribute to the progression of the tumor. Indeed, cancer cell survival, growth, migration, and even dormancy are influenced by the surrounding tumor microenvironment (TME). Within the TME, cancer-associated fibroblasts (CAFs) have been shown to play several roles in the development of a tumor. They secrete growth factors, inflammatory ligands, and extracellular matrix proteins that promote cancer cell proliferation, therapy resistance, and immune exclusion. However, recent work indicates that CAFs may also restrain tumor progression in some circumstances. In this review, we summarize the body of work on CAFs, with a particular focus on the most recent discoveries about fibroblast heterogeneity, plasticity, and functions. We also highlight the commonalities of fibroblasts present across different cancer types, and in normal and inflammatory states. Finally, we present the latest advances regarding therapeutic strategies targeting CAFs that are undergoing preclinical and clinical evaluation.

Heterogeneous Pancreatic Stellate Cells Are Powerful Contributors to the Malignant Progression of Pancreatic Cancer

Pancreatic cancer is associated with highly malignant tumors and poor prognosis due to strong therapeutic resistance. Accumulating evidence shows that activated pancreatic stellate cells (PSC) play an important role in the malignant progression of pancreatic cancer. In recent years, the rapid development of single-cell sequencing technology has facilitated the analysis of PSC population heterogeneity, allowing for the elucidation of the relationship between different subsets of cells with tumor development and therapeutic resistance. Researchers have identified two spatially separated, functionally complementary, and reversible subtypes, namely myofibroblastic and inflammatory PSC. Myofibroblastic PSC produce large amounts of pro-fibroproliferative collagen fibers, whereas inflammatory PSC express large amounts of inflammatory cytokines. These distinct cell subtypes cooperate to create a microenvironment suitable for cancer cell survival. Therefore, further understanding of the differentiation of PSC and their distinct functions will provide insight into more effective treatment options for pancreatic cancer patients.

G Protein-Coupled Estrogen Receptor Regulates Actin Cytoskeleton Dynamics to Impair Cell Polarization

Mechanical forces regulate cell functions through multiple pathways. G protein-coupled estrogen receptor (GPER) is a seven-transmembrane receptor that is ubiquitously expressed across tissues and mediates the acute cellular response to estrogens. Here, we demonstrate an unidentified role of GPER as a cellular mechanoregulator. G protein-coupled estrogen receptor signaling controls the assembly of stress fibers, the dynamics of the associated focal adhesions, and cell polarization via RhoA GTPase (RhoA). G protein-coupled estrogen receptor activation inhibits F-actin polymerization and subsequently triggers a negative feedback that transcriptionally suppresses the expression of monomeric G-actin. Given the broad expression of GPER and the range of cytoskeletal changes modulated by this receptor, our findings position GPER as a key player in mechanotransduction.

Non-alcoholic Fatty Liver Disease as a Canonical Example of Metabolic Inflammatory-Based Liver Disease Showing a Sex-Specific Prevalence: Relevance of Estrogen Signaling

There is extensive evidence supporting the interplay between metabolism and immune response, that have evolved in close relationship, sharing regulatory molecules and signaling systems, to support biological functions. Nowadays, the disruption of this interaction in the context of obesity and overnutrition underlies the increasing incidence of many inflammatory-based metabolic diseases, even in a sex-specific fashion. During evolution, the interplay between metabolism and reproduction has reached a degree of complexity particularly high in female mammals, likely to ensure reproduction only under favorable conditions. Several factors may account for differences in the incidence and progression of inflammatory-based metabolic diseases between females and males, thus contributing to age-related disease development and difference in life expectancy between the two sexes. Among these factors, estrogens, acting mainly through Estrogen Receptors (ERs), have been reported to regulate several metabolic pathways and inflammatory processes particularly in the liver, the metabolic organ showing the highest degree of sexual dimorphism. This review aims to investigate on the interaction between metabolism and inflammation in the liver, focusing on the relevance of estrogen signaling in counteracting the development and progression of non-alcoholic fatty liver disease (NAFLD), a canonical example of metabolic inflammatory-based liver disease showing a sex-specific prevalence. Understanding the role of estrogens/ERs in the regulation of hepatic metabolism and inflammation may provide the basis for the development of sex-specific therapeutic strategies for the management of such an inflammatory-based metabolic disease and its cardio-metabolic consequences.

Mechanically stressed cancer microenvironment: Role in pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies in the world due to its insensitivity to current therapies and its propensity to metastases from the primary tumor mass. This is largely attributed to its complex microenvironment composed of unique stromal cell populations and extracellular matrix (ECM). The recruitment and activation of these cell populations cause an increase in deposition of ECM components, which highly influences the behavior of malignant cells through disrupted forms of signaling. As PDAC progresses from premalignant lesion to invasive carcinoma, this dynamic landscape shields the mass from immune defenses and cytotoxic intervention. This microenvironment influences an invasive cell phenotype through altered forms of mechanical signaling, capable of enacting biochemical changes within cells through activated mechanotransduction pathways. The effects of altered mechanical cues on malignant cell mechanotransduction have long remained enigmatic, particularly in PDAC, whose microenvironment significantly changes over time. A more complete and thorough understanding of PDAC's physical surroundings (microenvironment), mechanosensing proteins, and mechanical properties may help in identifying novel mechanisms that influence disease progression, and thus, provide new potential therapeutic targets.

Environmentally controlled magnetic nano-tweezer for living cells and extracellular matrices

The magnetic tweezer technique has become a versatile tool for unfolding or folding of individual molecules, mainly DNA. In addition to single molecule analysis, the magnetic tweezer can be used to analyze the mechanical properties of cells and extracellular matrices. We have established a magnetic tweezer that is capable of measuring the linear and non-linear viscoelastic behavior of a wide range of soft matter in precisely controlled environmental conditions, such as temperature, CO₂ and humidity. The magnetic tweezer presented in this study is suitable to detect specific differences in the mechanical properties of different cell lines, such as human breast cancer cells and mouse embryonic fibroblasts, as well as collagen matrices of distinct concentrations in the presence and absence of fibronectin crosslinks. The precise calibration and control mechanism employed in the presented magnetic tweezer setup provides the ability to apply physiological force up to 5 nN on 4.5 µm superparamagnetic beads coated with fibronectin and coupled to the cells or collagen matrices. These measurements reveal specific local linear and non-linear viscoelastic behavior of the investigated samples. The viscoelastic response of cells and collagen matrices to the force application is best described by a weak power law behavior. Our results demonstrate that the stress stiffening response and the fluidization of cells is cell type specific and varies largely between differently invasive and aggressive cancer cells. Finally, we showed that the viscoelastic behavior of collagen matrices with and without fibronectin crosslinks measured by the magnetic tweezer can be related to the microstructure of these matrices.

Fibroblast Reprogramming in Gastrointestinal Cancer

Gastrointestinal cancers are a significant cause of cancer mortality worldwide and have been strongly linked with chronic inflammation. Current therapies focus on epithelial/cancer cells; however, the importance of the tumor microenvironment in the development and treatment of the disease is also now well established. Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment, and are actively participating in tumor initiation, promotion and metastasis. They structurally and functionally affect cancer cell proliferation, tumor immunity, angiogenesis, extracellular matrix remodeling and metastasis through a variety of signaling pathways. CAFs originate predominantly from resident mesenchymal cells, which are activated and reprogrammed in response to cues from cancer cells. In recent years, chronic inflammation of the gastrointestinal tract has also proven an important driver of mesenchymal cell activation and subsequent CAF development, which in turn are capable of regulating the transition from acute to chronic inflammation and cancer. In this review, we will provide a concise overview of the mechanisms that drive fibroblast reprogramming in cancer and the recent advances on the downstream signaling pathways that regulate the functional properties of the activated mesenchyme. This new mechanistic insight could pave the way for new therapeutic strategies and better prognosis for cancer patients.

Reprogramming of Mesothelial-Mesenchymal Transition in Chronic Peritoneal Diseases by Estrogen Receptor Modulation and TGF-β1 Inhibition

In chronic peritoneal diseases, mesothelial-mesenchymal transition is determined by cues from the extracellular environment rather than just the cellular genome. The transformation of peritoneal mesothelial cells and other host cells into myofibroblasts is mediated by cell membrane receptors, Transforming Growth Factor β1 (TGF-β1), Src and Hypoxia-inducible factor (HIF). This article provides a narrative review of the reprogramming of mesothelial mesenchymal transition in chronic peritoneal diseases, drawing on the similarities in pathophysiology between encapsulating peritoneal sclerosis and peritoneal metastasis, with a particular focus on TGF-β1 signaling and estrogen receptor modulators. Estrogen receptors act at the cell membrane/cytosol as tyrosine kinases that can phosphorylate Src, in a similar way to other receptor tyrosine kinases; or can activate the estrogen response element via nuclear translocation. Tamoxifen can modulate estrogen membrane receptors, and has been shown to be a potent inhibitor of mesothelial-mesenchymal transition (MMT), peritoneal mesothelial cell migration, stromal fibrosis, and neoangiogenesis in the treatment of encapsulating peritoneal sclerosis, with a known side effect and safety profile. The ability of tamoxifen to inhibit the transduction pathways of TGF-β1 and HIF and achieve a quiescent peritoneal stroma makes it a potential candidate for use in cancer treatments. This is relevant to tumors that spread to the peritoneum, particularly those with mesenchymal phenotypes, such as colorectal CMS4 and MSS/EMT gastric cancers, and pancreatic cancer with its desmoplastic stroma. Morphological changes observed during mesothelial mesenchymal transition can be treated with estrogen receptor modulation and TGF-β1 inhibition, which may enable the regression of encapsulating peritoneal sclerosis and peritoneal metastasis.

Pharmacologic Activation of the G Protein-Coupled Estrogen Receptor Inhibits Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

Female sex is associated with lower incidence and improved clinical outcomes for most cancer types including pancreatic ductal adenocarcinoma (PDAC). The mechanistic basis for this sex difference is unknown. We hypothesized that estrogen signaling may be responsible, despite the fact that PDAC lacks classic nuclear estrogen receptors.

METHODS

Here we used murine syngeneic tumor models and human xenografts to determine that signaling through the nonclassic estrogen receptor G protein-coupled estrogen receptor (GPER) on tumor cells inhibits PDAC.

RESULTS

Activation of GPER with the specific, small molecule, synthetic agonist G-1 inhibited PDAC proliferation, depleted c-Myc and programmed death ligand 1 (PD-L1), and increased tumor cell immunogenicity. Systemically administered G-1 was well-tolerated in PDAC bearing mice, induced tumor regression, significantly prolonged survival, and markedly increased the efficacy of PD-1 targeted immune therapy. We detected GPER protein in a majority of spontaneous human PDAC tumors, independent of tumor stage.

CONCLUSIONS

These data, coupled with the wide tissue distribution of GPER and our previous work showing that G-1 inhibits melanoma, suggest that GPER agonists may be useful against a range of cancers that are not classically considered sex hormone responsive and that arise in tissues outside of the reproductive system.

G protein-coupled estrogen receptor-1 agonist induces chemotherapeutic effect via ER stress signaling in gastric cancer

G protein-coupled estrogen receptor (GPER) is known to play an important role in hormone-associated cancers. G-1, a novel synthetic GPER agonist, has been reported to exhibit anti-carcinogenic properties. However, the chemotherapeutic mechanism of GPER is yet unclear. Here, we evaluated GPER expression in human gastric cancer tissues and cells. We found that G-1 treatment attenuates GPER expression in gastric cancer. GPER expression increased G-1-induced antitumor effects in mouse xenograft model. We analyzed the effects of knockdown/overexpression of GPER on G-1-induced cell death in cancer cells. Increased GPER expression in human gastric cancer cells increased G-1-induced cell death via increased levels of cleaved caspase-3, -9, and cleaved poly ADP-ribose polymerase. Interestingly, during G-1-induced cell death, GPER mRNA and protein expression was attenuated and associated with ER stress-induced expression of PERK, ATF-4, GRP-78, and CHOP. Furthermore, PERK-dependent induction of ER stress activation increased G-1-induced cell death, whereas PERK silencing decreased cell death and increased drug sensitivity. Taken together, the data suggest that the induction of ER stress via GPER expression may increase G-1-induced cell death in gastric cancer cells. These results may contribute to a new paradigm shift in gastric cancer therapy.

Influence of the Hippo-YAP signalling pathway on tumor associated macrophages (TAMs) and its implications on cancer immunosuppressive microenvironment

A large number of immune cells are present in the tumour microenvironment (TME), of which, tumour-associated macrophages (TAMs) are among the most important and highly infiltrated cells, and mainly include the M1 type classically activated and M2 type alternatively activated TAMs. Both cell types are known to play an important role in tumour initiation and proliferation. It has recently been confirmed that the TAMs in tumours tend to be dominated by the M2 type. However, the precise mechanism underlying TAM recruitment and polarization in the immune microenvironment remains to be elucidated. The Hippo-Yes-associated protein (YAP) signalling pathway is one of the most extensively discussed mechanism for the regulation of tumour proliferation, migration, angiogenesis, and invasion in recent years. To date, several studies have revealed that YAP is involved in the interrelating interactions between tumour and immune cells, particularly the TAMs. In this review, we have summarized the mechanism by which the YAP regulates the activity of TAMs and its impact on the TME.

Signaling in the Physiology and Pathophysiology of Pancreatic Stellate Cells - a Brief Review of Recent Advances

The interest in pancreatic stellate cells (PSCs) has been steadily growing over the past two decades due mainly to the central role these cells have in the desmoplastic reaction associated with diseases of the pancreas, such as pancreatitis or pancreatic cancer. In recent years, the scientific community has devoted substantial efforts to understanding the signaling pathways that govern PSC activation and interactions with neoplastic cells. This mini review aims to summarize some very recent findings on signaling in PSCs and highlight their impact to the field.

G Protein-Coupled Estrogen Receptor in Immune Cells and Its Role in Immune-Related Diseases

G protein-coupled estrogen receptor 1 (GPER1), is a functional estrogen receptor involved in estrogen related actions on several systems including processes of the nervous, reproductive, metabolic, cardiovascular, and immune system. Regarding the latter, GPER is expressed in peripheral B and T lymphocytes as well as in monocytes, eosinophils, and neutrophils. Several studies have implicated GPER in immune-mediated diseases like multiple sclerosis, Parkinson's disease, and atherosclerosis-related inflammation, while a recent report suggests that its deletion could be responsible for a form of familial immunodeficiency. It has also been suggested that it is a key regulator of immune-mediated events in breast, pancreatic, prostate, and hepatocellular cancer as well as in melanoma. GPER has been also reported to interact with classic ER-alpha or its splice variants in order to modify immune functions. This review aims to present current knowledge relating GPER to immune functions, the cellular and signaling pathways involved, as well as the potential clinical implications of GPER modulation in immune-related diseases.

GPER as a Receptor for Endocrine-Disrupting Chemicals (EDCs)

Endocrine-disrupting chemicals (EDCs) are exogenous chemicals that interfere with endogenous hormonal systems at various levels, resulting in adverse health effects. EDCs belong to diverse chemical families and can accumulate in the environment, diet and body fluids, with different levels of persistence. Their action can be mediated by several receptors, including members of the nuclear receptor family, such as estrogen and androgen receptors. The G protein-coupled estrogen receptor (GPER), a seven-transmembrane domain receptor, has also attracted attention as a potential target of EDCs. This review summarizes our current knowledge concerning GPER as a mediator of EDCs' effects.

Fibroblasts Fuel Immune Escape in the Tumor Microenvironment

Immune escape is central to the persistence of most, if not all, solid tumors and poses a critical obstacle to successful cancer (immuno)therapy. Cancer-associated fibroblasts (CAFs) constitute the most prevalent, yet heterogeneous, component of the tumor stroma, where they 'cool down' the immune microenvironment. The central role played by CAFs, both as a physical barrier and source of immunosuppressive molecules, sets them as a target to enhance immunotherapy of cancer. We outline the current understanding of how CAFs fuel immune escape, as well as their potential clinical applications. Whether these therapeutics really have clinically significant activity remains to be seen, but the outlook is positive.

Modulation of retinoid signaling: therapeutic opportunities in organ fibrosis and repair

The vitamin A metabolite, retinoic acid, is an important signaling molecule during embryonic development serving critical roles in morphogenesis, organ patterning and skeletal and neural development. Retinoic acid is also important in postnatal life in the maintenance of tissue homeostasis, while retinoid-based therapies have long been used in the treatment of a variety of cancers and skin disorders. As the number of people living with chronic disorders continues to increase, there is great interest in extending the use of retinoid therapies in promoting the maintenance and repair of adult tissues. However, there are still many conflicting results as we struggle to understand the role of retinoic acid in the multitude of processes that contribute to tissue injury and repair. This review will assess our current knowledge of the role retinoic acid signaling in the development of fibroblasts, and their transformation to myofibroblasts, and of the potential use of retinoid therapies in the treatment of organ fibrosis.

Clinical candidate and genistein analogue AXP107-11 has chemoenhancing functions in pancreatic adenocarcinoma through G protein-coupled estrogen receptor signaling

Despite advances in cancer therapeutics, pancreatic cancer remains difficult to treat and often develops resistance to chemotherapies. We have evaluated a bioavailable genistein analogue, AXP107-11 which has completed phase Ib clinical trial, as an approach to sensitize tumor cells to chemotherapy. Using organotypic cultures of 14 patient-derived xenografts (PDX) of pancreatic ductal adenocarcinoma, we found that addition of AXP107-11 indeed sensitized 57% of cases to gemcitabine treatment. Results were validated using PDX models in vivo. Further, RNA-Seq from responsive and unresponsive tumors proposed a 41-gene treatment-predictive signature. Functional and molecular assays were performed in cell lines and demonstrated that the effect was synergistic. Transcriptome analysis indicated activation of G-protein-coupled estrogen receptor (GPER1) as the main underlying mechanism of action, which was corroborated using GPER1-selective agonists and antagonists. GPER1 expression in pancreatic tumors was indicative of survival, and our study proposes that activation of GPER1 may constitute a new avenue for pancreatic cancer therapeutics.

Mechanism of GPER promoting proliferation, migration and invasion of triple-negative breast cancer cells through CAF

Triple-negative breast cancer (TNBC) is an important histological subtype of breast cancer. Abnormal GPER expression has been reported in human breast cancer. However, the functional mechanism of GPER through carcinoma-associated fibroblast (CAF) in TNBC needed further investigations. The proliferation and cycle progression of the MDA-MB-231 cells were respectively analyzed by CCK-8 assay and flow cytometry, while cell migration and invasion were examined by wound healing assay and transwell assay. GPER expression in TNBC tissues and MDA-MB-231 cells was investigated by RT-qPCR, western blotting and immunohistochemistry. Collagen-1 was measured using ELISA. In addition, the role of GPER through CAF was investigated through cells were transfected with GPER interference plasmid and treated with GPER agonist, respectively. The transfection effects were verified by RT-qPCR. The results demonstrated that CAF could promote proliferation, migration and invasion of MDA-MB-231 cells compared with normal fibroblast (NF). GPER expression was decreased in TNBC tissues and MDA-MB-231 cells in comparison with the adjacent normal tissues and MCF-10A cells. GPER expression could affect the expression of Coll-1 in CAF. Downregulation of GPER inhibited Coll-1 expression in CAF, thereby inducing the decrease of cell proliferation, arrest of S phase and suppression of migration and invasion of MDA-MB-231 cells, while GPER agonist could be resulted in the opposite effects. In conclusion, the present data demonstrated that GPER promoted proliferation, migration and invasion of TNBC cells through CAF. Furthermore, GPER expression was positively related to the prognosis of TNBC.

G protein-coupled estrogen receptor in colon function, immune regulation and carcinogenesis

Estrogens play important roles in the development and progression of multiple tumor types. Accumulating evidence points to the significance of estrogen action not only in tumors of hormonally regulated tissues such as the breast, endometrium and ovary, but also in the development of colorectal cancer (CRC). The effects of estrogens in physiological and pathophysiological conditions are mediated by the nuclear estrogen receptors α and β, as well as the membrane-bound G protein-coupled estrogen receptor (GPER). The roles of GPER in CRC development and progression, however, remain poorly understood. Studies on the functions of GPER in the colon have shown that this estrogen receptor regulates colonic motility as well as immune responses in CRC-associated diseases, such as Crohn’s disease and ulcerative colitis. GPER is also involved in cell cycle regulation, endoplasmic reticulum stress, proliferation, apoptosis, vascularization, cell migration, and the regulation of fatty acid and estrogen metabolism in CRC cells. Thus, multiple lines of evidence suggest that GPER may play an important role in colorectal carcinogenesis. In this review, we present the current state of knowledge regarding the contribution of GPER to colon function and CRC.

YAP1-mediated pancreatic stellate cell activation inhibits pancreatic cancer cell proliferation

Pancreatic stellate cells (PSCs) are activated in pancreatic ductal adenocarcinoma (PDAC) and are responsible for dense desmoplastic stroma. Yes-associated protein 1 (YAP1) can induce cancer-associated fibroblast activation in liver and breast tumors, but its effect on PSCs is unknown. In the present study, we determined that YAP1 was highly expressed in the nuclei of PDAC-derived activated PSCs. RNAi-mediated or pharmacological inhibition of YAP1 led to PSC deactivation. In addition, YAP1 stimulated the expression of secreted protein acidic and cysteine rich (SPARC) in PSCs, which was inhibited by RUNX1. SPARC secreted from PSCs inhibited pancreatic cancer cell (PCC) proliferation. High expression of nuclear YAP1 in tumor stroma was significantly correlated with SPARC expression and fibrosis degree in human PDAC tissues. Our study revealed a critical role for YAP1 in the regulation of PSC activation and paracrine signaling. Our findings provide insights into a novel rationale for targeting YAP1 to reprogram the PDAC microenvironment.