Higher CXCL16 exodomain is associated with aggressive ovarian cancer and promotes the disease by CXCR6 activation and MMP modulation

Personalization of Therapy in High-Grade Serous Tubo-Ovarian Cancer-The Possibility or the Necessity?

High-grade serous tubo-ovarian cancer (HGSTOC) is the most lethal tumor of the female genital tract. The foregoing therapy consists of cytoreduction followed by standard platinum/taxane chemotherapy; alternatively, for primary unresectable tumors, neo-adjuvant platinum/taxane chemotherapy followed by delayed interval cytoreduction. In patients with suboptimal surgery or advanced disease, different forms of targeted therapy have been accepted or tested in clinical trials. Studies on HGSTOC discovered its genetic and proteomic heterogeneity, epigenetic regulation, and the role of the tumor microenvironment. These findings turned attention to the fact that there are several distinct primary tumor subtypes of HGSTOC and the unique biology of primary, metastatic, and recurrent tumors may result in a differential drug response. This results in both chemo-refractoriness of some primary tumors and, what is significantly more frequent and destructive, secondary chemo-resistance of metastatic and recurrent HGSTOC tumors. Treatment possibilities for platinum-resistant disease include several chemotherapeutics with moderate activity and different targeted drugs with difficult tolerable effects. Therefore, the question appears as to why different subtypes of ovarian cancer are predominantly treated based on the same therapeutic schemes and not in an individualized way, adjusted to the biology of a specific tumor subtype and temporal moment of the disease. The paper reviews the genomic, mutational, and epigenetic signatures of HGSTOC subtypes and the tumor microenvironment. The clinical trials on personalized therapy and the overall results of a new, comprehensive approach to personalized therapy for ovarian cancer have been presented and discussed.

Investigating novel biomarkers in uterine corpus endometrial carcinoma: in silico analysis and clinical specimens validation via RT-qPCR and immunohistochemistry

The rising incidence and mortality rate of Uterine Corpus Endometrial Carcinoma (UCEC) pose significant health concerns. CC and CXC chemokines have been linked to tumorigenesis and cancer progression. Recognizing the growing significance of CC and CXC chemokines' diagnostic and prognostic significance in diverse cancer types, our objective was to comprehensively analyze the diagnostic and prognostic values of hub genes from the CC and CXC chemokines in UCEC, utilizing both in silico and clinical samples and cell lines-based approaches. In silico analyses include STRING, Cytoscape, Cytohubba, The Cancer Genome Atlas (TCGA) datasets analysis via the UALCAN, GEPIA, OncoDB, and MuTarget, SurvivalGenie, MEXPRESS, cBioPoratal, TIMER, ENCORI, and DrugBank. Meanwhile, clinical samples and cell lines based analyses include Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), targeted bisulfite sequencing (bisulfite-seq) analysis, and immunohistochemistry (IHC). Through present study, we identified CCL25 (CC motif chemokine ligand 25), CXCL10 (C-X-C motif chemokine ligand 10), CXCL12 (C-X-C motif chemokine ligand 12), and CXCL16 (C-X-C motif chemokine ligand 16) as crucial hub genes among the CC and CXC chemokines. Analyzing the expression data from TCGA, we observed a significant up-regulation of CCL25, CXCL10, and CXCL16 in UCEC samples compared to controls. In contrast, we noted a significant down-regulation of CXCL12 expression in UCEC samples. On clinical UCEC samples and cell lines analysis, the significant higher expression of CCL25, CXCL10, and CXCL16 and significant lower expression of CXCL12 were also denoted in UCEC samples than the controls via RT-qPCR and IHC analyses. Moreover, in silico analysis also confirmed the abnormal promoter methylation levels of the hub genes in TCGA UCEC samples, which was later validated by the clinical samples using targeted based bisulfite-seq analysis. In addition, various additional aspects of the CCL25, CXCL10, CXCL12, and CXCL16 have also been uncovered in UCEC during the present study. Our findings offer novel insights that contribute to the clinical utility of CCL25, CXCL10, CXCL12, and CXCL16 chemokines as potential diagnostic and prognostic biomarkers in UCEC.

Chemokines expressed by engineered bacteria recruit and orchestrate antitumor immunity

Tumors use multiple mechanisms to actively exclude immune cells involved in antitumor immunity. Strategies to overcome these exclusion signals remain limited due to an inability to target therapeutics specifically to the tumor. Synthetic biology enables engineering of cells and microbes for tumor-localized delivery of therapeutic candidates previously unavailable using conventional systemic administration techniques. Here, we engineer bacteria to intratumorally release chemokines to attract adaptive immune cells into the tumor environment. Bacteria expressing an activating mutant of the human chemokine CXCL16 (hCXCL16K42A) offer therapeutic benefit in multiple mouse tumor models, an effect mediated via recruitment of CD8+ T cells. Furthermore, we target the presentation of tumor-derived antigens by dendritic cells, using a second engineered bacterial strain expressing CCL20. This led to type 1 conventional dendritic cell recruitment and synergized with hCXCL16K42A-induced T cell recruitment to provide additional therapeutic benefit. In summary, we engineer bacteria to recruit and activate innate and adaptive antitumor immune responses, offering a new cancer immunotherapy strategy.

Integration of local and systemic immunity in ovarian cancer: Implications for immunotherapy

Cancer is a disease that induces many local and systemic changes in immunity. The difficult nature of ovarian cancer stems from the lack of characteristic symptoms that contributes to a delayed diagnosis and treatment. Despite the enormous progress in immunotherapy, its efficacy remains limited. The heterogeneity of tumors, lack of diagnostic biomarkers, and complex immune landscape are the main challenges in the treatment of ovarian cancer. Integrative approaches that combine the tumor microenvironment - local immunity - together with periphery - systemic immunity - are urgently needed to improve the understanding of the disease and the efficacy of treatment. In fact, multiparametric analyses are poised to improve our understanding of ovarian tumor immunology. We outline an integrative approach including local and systemic immunity in ovarian cancer. Understanding the nature of both localized and systemic immune responses will be crucial to boosting the efficacy of immunotherapies in ovarian cancer patients.

CXCR6 expressing T cells: Functions and role in the control of tumors

CXCR6 is a receptor for the chemokine CXCL16, which exists as a membrane or soluble form. CXCR6 is a marker for resident memory T (TRM) cells that plays a role in immunosurveillance through their interaction with epithelial cells. The interaction of CXCR6 with CXCL16 expressed at the membrane of certain subpopulations of intratumor dendritic cells (DC) called DC3, ideally positions these CXCR6+ T cells to receive a proliferation signal from IL-15 also presented by DC3. Mice deficient in cxcr6 or blocking the interaction of CXCR6 with its ligand, experience a poorer control of tumor proliferation by CD8+ T cells, but also by NKT cells especially in the liver. Intranasal vaccination induces CXCL16 production in the lungs and is associated with infiltration by TRM expressing CXCR6, which are then required for the efficacy of anti-tumor vaccination. Therapeutically, the addition of CXCR6 to specific CAR-T cells enhances their intratumoral accumulation and prolongs survival in animal models of pancreatic, ovarian and lung cancer. Finally, CXCR6 is part of immunological signatures that predict response to immunotherapy based on anti-PD-(L)1 in various cancers. In contrast, a protumoral role of CXCR6+T cells has also been reported mainly in Non-alcoholic steatohepatitis (NASH) due to a non-antigen specific mechanism. The targeting and amplification of antigen-specific TRM expressing CXCR6 and its potential use as a biomarker of response to immunotherapy opens new perspectives in cancer treatment.

Chemokines and NSCLC: Emerging role in prognosis, heterogeneity, and therapeutics

Lung cancer persists to contribute to one-quarter of cancer-associated deaths. Among the different histologies, non-small cell lung cancer (NSCLC) alone accounts for 85% of the cases. The development of therapies involving immune checkpoint inhibitors and angiogenesis inhibitors has increased patients' survival probability and reduced mortality rates. Developing targeted therapies against essential genetic alterations also translates to better treatment strategies. But the benefits still seem farfetched due to the development of drug resistance and refractory tumors. In this review, we have highlighted the interplay of different tumor microenvironment components, essentially discussing the chemokine families (CC, CXC, C, and CX3C) that regulate the tumor biology in NSCLC and promote tumor growth, metastasis, and associated heterogeneity. The development of therapeutics and prognostic markers is a complex and multipronged approach. However, some essential chemokines can act as critical players for being considered potential prognostic markers and therapeutic targets.

Harnessing the chemokine system to home CAR-T cells into solid tumors

CAR-T cell therapy has been heralded as a breakthrough in the field of immunotherapy, but to date, this success has been limited to hematological malignancies. By harnessing the chemokine system and taking into consideration the chemokine expression profile in the tumor microenvironment, CAR-T cells may be homed into tumors to facilitate direct tumor cell cytolysis and overcome a major hurdle in generating effective CAR-T cell responses to solid cancers.

Resveratrol Inhibited ADAM10 Mediated CXCL16-Cleavage and T-Cells Recruitment to Pancreatic β-Cells in Type 1 Diabetes Mellitus in Mice

Background: CXCL16 attracts T-cells to the site of inflammation after cleaving by A Disintegrin and Metalloproteinase (ADAM10). Aim: The current study explored the role of ADAM10/CXCL16/T-cell/NF-κB in the initiation of type 1 diabetes (T1D) with special reference to the potential protecting role of resveratrol (RES). Methods: Four sets of Balb/c mice were created: a diabetes mellitus (DM) group (streptozotocin (STZ) 55 mg/kg, i.p.], a control group administered buffer, a RES group [RES, 50 mg/kg, i.p.), and a DM + RES group (RES (50 mg/kg, i.p.) and STZ (55 mg/kg, i.p.) administered daily for 12 days commencing from the fourth day of STZ injection). Histopathological changes, fasting blood insulin (FBI), glucose (FBG), serum and pancreatic ADAM10, CXCL16, NF-κB, T-cells pancreatic expression, inflammatory, and apoptotic markers were analyzed. Results: FBG, inflammatory and apoptotic markers, serum TNF-α, cellular CXCL16 and ADAM10 protein expression, pancreatic T-cell migration and NF-κB were significantly increased in diabetic mice compared to normal mice. RES significantly improved the biochemical and inflammatory parameters distorted in STZ-treated mice. Conclusions: ADAM10 promotes the cleaved form of CXCL16 driving T-cells into the islets of the pancreatic in T1D. RES successfully prevented the deleterious effect caused by STZ. ADAM10 and CXCL16 may serve as novel therapeutic targets for T1D.

Synergistic Analysis of Circulating Tumor Cells Reveals Prognostic Signatures in Pilot Study of Treatment-Naïve Metastatic Pancreatic Cancer Patients

Simple Summary

Pancreatic cancer is one of the most deadly cancer types because it usually is not diagnosed until the cancer has spread throughout the body. In this study, we isolate cancer cells found in the blood of pancreatic cancer patients called circulating tumor cells (CTCs) to study their mutation and gene expression profiles. Comparing patients with better and worse survival duration revealed signatures found in these cancer cells. Characterizing these signatures may help improve patient care by using alternative treatment options.

Abstract

Pancreatic ductal adenocarcinoma is typically diagnosed at late stages and has one of the lowest five-year survival rates of all malignancies. In this pilot study, we identify signatures related to survival and treatment response found in circulating tumor cells (CTCs). Patients with poor survival had increased mutant KRAS expression and deregulation of connected pathways such as PI3K-AKT and MAPK signaling. Further, in a subset of these patients, expression patterns of gemcitabine resistance mechanisms were observed, even prior to initiating treatment. This work highlights the need for identifying patients with these resistance profiles and designing treatment regimens to circumvent these mechanisms.

Immunological configuration of ovarian carcinoma: features and impact on disease outcome

Epithelial ovarian carcinoma (EOC) is a relatively rare malignancy but is the fifth-leading cause of cancer-related death in women, largely reflecting early, prediagnosis dissemination of malignant disease to the peritoneum. At odds with other neoplasms, EOC is virtually insensitive to immune checkpoint inhibitors, correlating with a tumor microenvironment that exhibits poor infiltration by immune cells and active immunosuppression. Here, we comparatively summarize the humoral and cellular features of primary and metastatic EOC, comparatively analyze their impact on disease outcome, and propose measures to alter them in support of treatment sensitivity and superior patient survival.

CXCR6-CXCL16 Axis Promotes Breast Cancer by Inducing Oncogenic Signaling

Simple Summary

Breast cancer (BrCa) is the second leading cause of cancer-related deaths in American women, and its incidence is on the rise. Insufficient understanding of the mechanisms leading to BrCa limits the effectiveness of the treatment. In this article, we show the importance of a chemokine axis-CXCR6/CXCL16 in supporting BrCa progression. We have delineated BrCa-promoting mechanisms induced by this chemokine axis at the molecular level. This work projects the therapeutic significance of CXCR6/CXCL16 signaling for the treatment of BrCa.

Abstract

Precise mechanisms underlying breast cancer (BrCa) metastasis are undefined, which becomes a challenge for effective treatments. Chemokine signaling instigates the trafficking of cancer cells in addition to leukocytes. This study aimed to ascertain the clinical and biological significance of the CXCR6/CXCL16 signaling axis in the pathobiology of BrCa. Our data show a higher expression of CXCR6 in BrCa cell lines and tissues. Stage-III BrCa tissues express significantly higher CXCR6 compared to stage-II tissues. The ligand, CXCL16, could remain tethered to the cell surface, and, after proteolytic shedding of the ectodomain, the N-terminal fragment is released, converting it to its oncogenic, soluble form. Like CXCR6, N-terminal CXCL16 and ADAM-10 were significantly higher in stage-III than stage-II, but no significant difference was observed in the C-terminal fragment of CXCL16. Further, stimulation of the CXCR6/CXCL16 axis activated Src, FAK, ERK1/2, and PI3K signaling pathways, as per antibody microarray analysis, which also underlie CXCL16-induced F-actin polymerization. The CXCR6/CXCL16 axis induces cytoskeleton rearrangement facilitating migration and invasion and supports BrCa cell survival by activating the PI3K/Akt pathway. This study highlights the significance of the CXCR6/CXCL16 axis and ADAM10 as potential therapeutic targets for advanced-stage BrCa.

CXC chemokine ligand 16: a Swiss army knife chemokine in cancer

Today, cancer is one of the leading causes of death worldwide. Lately, cytokine and chemokine imbalances have gained attention amongst different involved pathways in cancer development and attracted much consideration in cancer research. CXCL16, as a member of the CXC subgroup of chemokines, has been attributed to be responsible for immune cell infiltration into the tumour microenvironment. The aberrant expression of CXCL16 has been observed in various cancers. This chemokine has been shown to play a conflicting role in tumour development through inducing pro-inflammatory conditions. The infiltration of various immune and non-immune cells such as lymphocytes, cancer-associated fibroblasts and myeloid-derived suppressor cells by CXCL16 into the tumour microenvironment has complicated the tumour fate. Given this diverse role of CXCL16 in cancer, a better understanding of its function might build-up our knowledge about tumour biology. Hence, this study aimed to review the impact of CXCL16 in cancer and explored its therapeutic application. Consideration of these findings might provide opportunities to achieve novel approaches in cancer treatment and its prognosis.

The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (T_reg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

Determination of Potential Therapeutic Targets and Prognostic Markers of Ovarian Cancer by Bioinformatics Analysis

This study is to study the expression of CXCRs in ovarian cancer tissues and their value in prognosis. The expressions of CXCR1-CXCR7 mRNA between ovarian tumor tissues and normal tissues and in different pathological types of ovarian tumor tissues were compared by ONCOMINE online tool. The relationship between the expression of CXCRs and clinical pathological staging was studied by GEPIA. Kaplan-Meier plotter online tool was used to analyze prognosis. Finally, GO and KEGG analyses and protein interaction network analysis were performed for CXCRs by the DAVID software to predict their function, and cBioPortal was used to identify the key functional genes. The expression of CXCR3/4/7 mRNA in ovarian cancer tissues was higher than that in normal ovarian tissues, and the expression of CXCR4 was the highest (fold change = 306.413, P < 0.05). The expression of CXCR1/2/3/4/7 mRNA in different pathological types of ovarian tumors was significantly different (P < 0.05). Only CXCR5 expression level was associated with tumor staging. Survival analysis showed that high CXCR7 mRNA expression and low CXCR5/6 expression were associated with the shortening of overall survival. High CXCR4/7 expression and low CXCR5/6 expression were associated with the shortening of progression-free survival. High CXCR2/4 expression and low CXCR5/6 expression were closely related to the shortening of postprogressing survival. Protein interaction network analysis showed that GNB1, PTK2, MAPK1, PIK3CA, GNB4, GNA11, KNG1, and ARNT proteins were closely related to the CXC receptor family. CXCR3/4/7 are potential therapeutic targets, and CXCR2/4/5/6/7 are new markers for the prognosis of ovarian cancer.

A novel seven-gene panel predicts the sensitivity and prognosis of head and neck squamous cell carcinoma treated with platinum-based radio(chemo)therapy

PURPOSE

The aim of the study is to identify a reliable gene panel to predict the prognosis of HNSCC patients by integrated genomic analysis.

METHODS

Co-expression gene networks were constructed by WGCNA using GSE113282 gene expression profile. The biological functional investigation was performed by GO and KEGG function enrichment analysis. The hub gene module was screened by PPI. The prognostic gene panel was established by Lasso regression analysis, and further progression-free survival (PFS) analysis was validated by Kaplan-Meier survival analysis using GSE102995 data.

RESULTS

We identified 195 genes associated with the overall survival (OS) status (correlation coefficients: - 0.42, and p value: 2e-05) by WGCNA. These genes were enriched in immune-related cytokines and pathways analyzed by GO and KEGG. Among the 195 genes, the module (42 genes) with the highest score was screened by PPI. A novel seven-gene predictive panel (CD19, CD40LG, CD5, CXCR6, FPR2, NCAM1, and SELL) was established by Lasso regression analysis, and the area under ROC curve (AUC) for 3-year OS status was 0.8298 and 0.7571, respectively, in the training set and the test set. The PFS time of the low-risk patients was significantly longer than the high-risk patients (p < 0.0001; log-rank test) by further validation using GSE102995 data.

CONCLUSION

The seven-gene panel may serve as a reliable predictive tool for HNSCC patients treated with platinum-based radio (chemo) therapy, and may be potential therapeutic targets for HNSCC patients.

Bioinformatics Analysis of Potential Therapeutic Targets and Prognostic Biomarkers amid CXC Chemokines in Ovarian Carcinoma Microenvironment

Background

Ovarian cancer (OC) is one of the leading lethal gynecologic cancers of women around the world. More than 70% of patients are diagnosed with stage III or IV with poor outcome. This is partly because of lacking early effective screening techniques and potential biomarkers of OC. CXC chemokines in tumor microenvironment (TME) and their interaction with relative receptors can excite the downstream signaling pathways to influence tumor progression. However, the role of CXC chemokines in OC has not been identified.

Methods

ONCOMINE, GEPIA, Kaplan–Meier plotter, cBioPortal, TIMER, Metascape, and LinkedOmics were applied in our study.

Results

The transcriptional levels of CXCL1/8/9/10/11/12/13/14/16/17 were significantly elevated while CXCL3 was obviously reduced in OC vs normal ovarian tissue. CXCL8/9/11/13 were correlated with clinic pathological stage. Patients with low expression of CXCL8/9/11/13 were associated with better prognosis. We also found that CXCL3 and CXC12 could be used as potential prognostic markers of OC through Kaplan–Meier plotter. Patients with high expression of CXCL3/12 had a significantly better prognosis. Their functions focus on locomotion, signaling, response to stimulus, undergoing the process of multiorganism, immune system, biological regulation, etc. The differentiated CXC chemokines mainly participate in cytokine-cytokine receptor interaction, chemokine signaling pathway, IL-17 signaling pathway, and toll-like receptor signaling pathway. Our results showed that CXC chemokines were highly correlated with infiltration of immune cells. The kinase targets of differentially expressed CXC chemokines are mainly in ATM, LYN, LCK, PLK1, FYN, CDK2, and ATR.

Conclusions

Our results may provide a new insight for selecting precision biomarkers of targeted therapy of OC.

Characterization of the Prognostic Values of the CXCR1-7 in Clear Cell Renal Cell Carcinoma (ccRCC) Microenvironment

Background: As cancer immunotherapy has become a hot research topic, the values of CXC chemokine receptors (CXCRs) in tumor microenvironment have been increasingly realized. More and more evidence showed that the aberrant expression of CXCRs is closely related to the prognosis of various cancers. However, prognostic values and the exact roles of different CXCRs in clear cell renal cell carcinoma (ccRCC) have not yet been elucidated.

Methods: To further evaluate the potential of seven CXCRs as prognostic biomarkers for ccRCC, multiple online analysis tools, including ONCOMINE, UALCAN (TCGA dataset), Kaplan–Meier Plotter, MethSurv, cBioPortal, GEPIA, Metascape, and TIMER databases, were utilized in our research.

Results: The mRNA expression of CXCR4/6/7 was significantly increased in ccRCC patients, and all CXCRs are remarkably related to tumor stage or grade of ccRCC. Higher levels of CXCR3/4/5/6 expression were correlated with worse overall survival (OS) in patients with ccRCC, while higher expression of CXCR2 was associated with better OS. 23.14% mutation rate (118/510) of CXCR1-7 was observed in ccRCC patients, and the genetic alterations in CXCRs were related to worse OS and progression-free survival in ccRCC patients. Additionally, 53 CpGs of CXCR1-7 showed significant prognostic values. For functional enrichment, our results showed that CXCRs and their similar genes may be involved in cancer-associated pathways, immune process, and angiogenesis, etc. Besides, CXCRs were significantly correlated with multiple immune cells (e.g., CD8+ T cell, CD4+ cell, and dendritic cell).

Conclusion: This study explored the potential prognostic values and roles of the CXCRs in ccRCC microenvironment. Our results suggested that CXCR4 and CXCR6 could be the prognostic biomarkers for the patients with ccRCC.

CXC Chemokine Receptors in the Tumor Microenvironment and an Update of Antagonist Development

Chemokine receptors, a diverse group within the seven-transmembrane G protein-coupled receptor superfamily, are frequently overexpressed in malignant tumors. Ligand binding activates multiple downstream signal transduction cascades that drive tumor growth and metastasis, resulting in poor clinical outcome. These receptors are thus considered promising targets for anti-tumor therapy. This article reviews recent studies on the expression and function of CXC chemokine receptors in various tumor microenvironments and recent developments in cancer therapy using CXC chemokine receptor antagonists.

Phosphodiesterase 5 (PDE5) Is Highly Expressed in Cancer-Associated Fibroblasts and Enhances Breast Tumor Progression

The overexpression of phosphodiesterase (PDE) 5 is frequently found in various human cancers, such as those of the breast. However, PDE5’s role in the tumor microenvironment is still unknown. As PDE5 represents a high-value therapeutic target, we investigated whether the expression and function of PDE5 in breast cancer-associated fibroblasts (CAFs) may be clinically relevant to malignant progression. PDE5 expression was increased in human breast cancer stroma compared with normal stroma and was correlated to a shorter overall survival. Treatment of CAFs, isolated from breast tumor biopsies, with selective PDE5 inhibitors inhibited their proliferation, motility, and invasiveness, and negatively controlled tumor–stroma interactions in both ‘in vitro’ and ‘in vivo’ models. PDE5 stable overexpression transformed immortalized mouse embryonic fibroblasts (MEFs) towards an activated fibroblast phenotype, impacting their intrinsic characteristics and paracrine effects on breast cancer cell growth and migration through an enhanced production of the C-X-C motif chemokine 16 (CXCL16). On the other hand, CAF exposure to PDE5 inhibitors was associated with reduced CXCL16 expression and secretion. Importantly, CXCL16 levels in breast cancer stroma showed a strong correlation with PDE5 levels and poor patient outcomes. In conclusion, PDE5 is overexpressed in breast cancer stroma, enhances the tumor-stimulatory activities of fibroblasts, and impacts clinical outcomes; thus, we propose this enzyme as an attractive candidate for prognosis and a potential target for treatments in breast cancer patients.

Detection and Quantification of GPCR mRNA: An Assessment and Implications of Data from High-Content Methods

G protein-coupled receptors (GPCRs) are the largest family of membrane receptors and targets for approved drugs. The analysis of GPCR expression is, thus, important for drug discovery and typically involves messenger RNA (mRNA)-based methods. We compared transcriptomic complementary DNA (cDNA) (Affymetrix) microarrays, RNA sequencing (RNA-seq), and quantitative polymerase chain reaction (qPCR)-based TaqMan arrays for their ability to detect and quantify expression of endoGPCRs (nonchemosensory GPCRs with endogenous agonists). In human pancreatic cancer-associated fibroblasts, RNA-seq and TaqMan arrays yielded closely correlated values for GPCR number (∼100) and expression levels, as validated by independent qPCR. By contrast, the microarrays failed to identify ∼30 such GPCRs and generated data poorly correlated with results from those methods. RNA-seq and TaqMan arrays also yielded comparable results for GPCRs in human cardiac fibroblasts, pancreatic stellate cells, cancer cell lines, and pulmonary arterial smooth muscle cells. The magnitude of mRNA expression for several Gq/11-coupled GPCRs predicted cytosolic calcium increase and cell migration by cognate agonists. RNA-seq also revealed splice variants for endoGPCRs. Thus, RNA-seq and qPCR-based arrays are much better suited than transcriptomic cDNA microarrays for assessing GPCR expression and can yield results predictive of functional responses, findings that have implications for GPCR biology and drug discovery.