FAK Inhibition disrupts a β5 integrin signaling axis controlling anchorage-independent ovarian carcinoma growth

Focal adhesion kinase signaling - tumor vulnerabilities and clinical opportunities

Focal adhesion kinase (FAK; encoded by PTK2) was discovered over 30 years ago as a cytoplasmic protein tyrosine kinase that is localized to cell adhesion sites, where it is activated by integrin receptor binding to extracellular matrix proteins. FAK is ubiquitously expressed and functions as a signaling scaffold for a variety of proteins at adhesions and in the cell cytoplasm, and with transcription factors in the nucleus. FAK expression and intrinsic activity are essential for mouse development, with molecular connections to cell motility, cell survival and gene expression. Notably, elevated FAK tyrosine phosphorylation is common in tumors, including pancreatic and ovarian cancers, where it is associated with decreased survival. Small molecule and orally available FAK inhibitors show on-target inhibition in tumor and stromal cells with effects on chemotherapy resistance, stromal fibrosis and tumor microenvironment immune function. Herein, we discuss recent insights regarding mechanisms of FAK activation and signaling, its roles as a cytoplasmic and nuclear scaffold, and the tumor-intrinsic and -extrinsic effects of FAK inhibitors. We also discuss results from ongoing and advanced clinical trials targeting FAK in low- and high-grade serous ovarian cancers, where FAK acts as a master regulator of drug resistance. Although FAK is not known to be mutationally activated, preventing FAK activity has revealed multiple tumor vulnerabilities that support expanding clinical combinatorial targeting possibilities.

Integrin β5 is an independent prognostic marker for intrahepatic cholangiocarcinoma in a Chinese population

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver tumor and a major cause of cancer mortality worldwide. Integrin β5 (ITGB5) is considered to be involved in the intercellular signal transduction and regulation of tumorigenesis and development. The present study investigated the association between ITGB5 expression levels and the prognosis of ICC, as well as the effects of ITGB5 on the proliferation and invasion of ICC cells. RNA-sequencing transcriptomic profiling data of ICC samples were retrieved from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Tissue specimens from patients with ICC treated at Taizhou People's Hospital were collected and the ITGB5 expression levels were evaluated using immunohistochemical staining. The biological function of ITGB5 in ICC was investigated using Gene Ontology (GO), Gene Set Enrichment Analysis (GSEA) and in vitro experiments using HuCCT1 cells. After knocking down ITGB5 expression, cell proliferation was detected using Cell Counting Kit-8 assay, while cell invasion was assessed using Transwell assays. According to TCGA dataset, ITGB5 was highly expressed in ICC; however, there was no significant difference in prognosis between patients with high and low ITGB5 expression levels. High expression of ITGB5 was present in the tissues of patients with ICC from the GEO database, which was associated with poor prognosis. Survival analyses of the clinical data obtained in the present study revealed that high expression levels of ITGB5 in patients with ICC were associated with a reduced overall survival. GO and GSEA indicated that genes associated with ITGB5 were enriched in the extracellular matrix-receptor interaction and focal adhesion signaling pathways. Silencing ITGB5 inhibited the proliferation and invasion of ICC cells. In conclusion, ITGB5 may act as an essential regulator of ICC development and progression by influencing the proliferation and invasion of ICC cells. However, future studies with larger sample sizes are required to validate the role of ITGB5 in the prognosis of patients with ICC.

Long non-coding RNA NRSN2-AS1 promotes ovarian cancer progression through targeting PTK2/β-catenin pathway

As a common malignant tumor among women, ovarian cancer poses a serious threat to their health. This study demonstrates that long non-coding RNA NRSN2-AS1 is over-expressed in ovarian cancer tissues using patient sample and tissue microarrays. In addition, NRSN2-AS1 is shown to promote ovarian cancer cell proliferation and metastasis both in vitro and in vivo. Mechanistically, NRSN2-AS1 stabilizes protein tyrosine kinase 2 (PTK2) to activate the β-catenin pathway via repressing MG-53-mediated ubiquitinated degradation of PTK2, thereby facilitating ovarian cancer progression. Rescue experiments verify the function of the NRSN2-AS1/PTK2/β-catenin axis and the effects of MG53 on this axis in ovarian cancer cells. In conclusion, this study demonstrates the key role of the NRSN2-AS1/PTK2/β-catenin axis for the first time and explores its potential clinical applications in ovarian cancer.

Ascitic autotaxin as a potential prognostic, diagnostic, and therapeutic target for epithelial ovarian cancer

BACKGROUND

Malignant ascites contributes to the metastatic process by facilitating the multifocal dissemination of ovarian tumour cells onto the peritoneal surface. However, the prognostic and diagnostic relevance of ascitic fluid remains largely unknown. Herein, we investigated the potential clinical value and therapeutic utility of ascitic autotaxin (ATX) in epithelial ovarian cancer (EOC).

METHODS

ATX expression was assessed in clinical samples. Spheroid-forming assay, real-time PCR, western blot analysis, invadopodia assay, and adhesion assays were performed.

RESULTS

Ascitic ATX expression was highly elevated in patients with ovarian cancer compared to those with benign ascites and was associated with advanced stage, high grade, and a short disease-free period in patients with EOC. Combining the diagnostic ability of ascitic ATX and serum CA-125 levels significantly improved the area under the curve (AUC) value for EOC compared to serum CA125 level alone. This marker combination showed a large odds ratio for short disease-free period in high-risk EOC groups. Functional studies revealed that ascitic ATX was required for maintaining cancer stem cell-like characteristics and invadopodia formation.

CONCLUSION

Ascitic ATX levels may serve as a useful prognostic indicator for predicting aggressive behaviour in EOC. ATX-linked invadopodia are a potential target to prevent peritoneal dissemination in ovarian cancer.

FAK PROTAC Inhibits Ovarian Tumor Growth and Metastasis by Disrupting Kinase Dependent and Independent Pathways

Focal adhesion kinase (FAK) is highly expressed in a variety of human cancers and is a target for cancer therapy. Since FAK kinase inhibitors only block the kinase activity of FAK, they are not highly effective in clinical trials. FAK also functions as a scaffold protein in a kinase-independent pathway. To effectively target FAK, it is required to block both FAK kinase-dependent and FAK-independent pathways. Thus, we tested a new generation drug FAK PROTAC for ovarian cancer therapy, which blocks both kinase and scaffold activity. We tested the efficacy of FAK PROTAC and its parent kinase inhibitor (VS-6063) in ovarian cancer cell lines in vitro by performing cell functional assays including cell proliferation, migration, invasion. We also tested in vivo activity in orthotopic ovarian cancer mouse models. In addition, we assessed whether FAK PROTAC disrupts kinase-dependent and kinase-independent pathways. We demonstrated that FAK PROTAC is highly effective as compared to its parent FAK kinase inhibitor VS-6063 in inhibiting cell proliferation, survival, migration, and invasion. FAK PROTAC not only inhibits the FAK kinase activity but also FAK scaffold function by disrupting the interaction between FAK and its interaction protein ASAP1. We further showed that FAK PROTAC effectively inhibits ovarian tumor growth and metastasis. Taken together, FAK PROTAC inhibits both FAK kinase activity and its scaffold protein activity by disrupting the interaction between FAK and ASAP1 and is highly effective in inhibiting ovarian tumor growth and metastasis.

Clinical significance of metabolism-related genes and FAK activity in ovarian high-grade serous carcinoma

BACKGROUND

Administration of poly (ADP-ribose) polymerase (PARP) inhibitors after achieving a response to platinum-containing drugs significantly prolonged relapse-free survival compared to placebo administration. PARP inhibitors have been used in clinical practice. However, patients with platinum-resistant relapsed ovarian cancer still have a poor prognosis and there is an unmet need. The purpose of this study was to examine the clinical significance of metabolic genes and focal adhesion kinase (FAK) activity in advanced ovarian high-grade serous carcinoma (HGSC).

METHODS

The RNA sequencing (RNA-seq) data and clinical data of HGSC patients were obtained from the Genomic Data Commons (GDC) Data Portal and analysed ( https://portal.gdc.cancer.gov/ ). In addition, tumour tissue was sampled by laparotomy or screening laparoscopy prior to treatment initiation from patients diagnosed with stage IIIC ovarian cancer (International Federation of Gynecology and Obstetrics (FIGO) classification, 2014) at the Saitama Medical University International Medical Center, and among the patients diagnosed with HGSC, 16 cases of available cryopreserved specimens were included in this study. The present study was reviewed and approved by the Institutional Review Board of Saitama Medical University International Medical Center (Saitama, Japan). Among the 6307 variable genes detected in both The Cancer Genome Atlas-Ovarian (TCGA-OV) data and clinical specimen data, 35 genes related to metabolism and FAK activity were applied. RNA-seq data were analysed using the Subio Platform (Subio Inc, Japan). JMP 15 (SAS, USA) was used for statistical analysis and various types of machine learning. The Kaplan-Meier method was used for survival analysis, and the Wilcoxon test was used to analyse significant differences. P < 0.05 was considered significant.

RESULTS

In the TCGA-OV data, patients with stage IIIC with a residual tumour diameter of 1-10 mm were selected for K means clustering and classified into groups with significant prognostic correlations (p = 0.0444). These groups were significantly associated with platinum sensitivity/resistance in clinical cases (χ2 test, p = 0.0408) and showed significant relationships with progression-free survival (p = 0.0307).

CONCLUSION

In the TCGA-OV data, 2 groups classified by clustering focusing on metabolism-related genes and FAK activity were shown to be associated with platinum resistance and a poor prognosis.

Focal adhesion kinase inhibitors in the treatment of solid tumors: Preclinical and clinical evidence

Focal Adhesion Kinase (FAK) is a 125-kDa cytoplasmic protein kinase that is implicated in several cellular functions. This protein is an attractive molecular target for cancer therapy because a wide variety of studies have demonstrated associations between the activation or elevated expression of FAK and tumor progression, invasion, and drug resistance in malignant tumors. Here, we review the strategies used to inhibit FAK activity in solid tumors. We also include an overview of the preclinical (in vitro and in vivo) and clinical studies on FAK inhibitors.

Mirage or long-awaited oasis: reinvigorating T-cell responses in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is plagued by a dismal 5-year survival rate, early onset of metastasis and limited efficacy of systemic therapies. This scenario highlights the need to fervently pursue novel therapeutic strategies to treat this disease. Recent research has uncovered complicated dynamics within the tumor microenvironment (TME) of PDAC. An abundant stroma provides a framework for interactions between cancer-associated fibroblasts, suppressive myeloid cells and regulatory lymphocytes, which together create an inhospitable environment for adaptive immune responses. This accounts for the poor infiltration and exhausted phenotypes of effector T cells within pancreatic tumors. Innovative studies in genetically engineered mouse models have established that with appropriate pharmacological modulation of suppressive elements in the TME, T cells can be prompted to regress pancreatic tumors. In light of this knowledge, innovative combinatorial strategies involving immunotherapy and targeted therapies working in concert are rapidly emerging. This review will highlight recent advances in the field related to immune suppression in PDAC, emerging preclinical data and rationale for ongoing immunotherapy clinical trials. In particular, we draw attention to foundational findings involving T-cell activity in PDAC and encourage development of novel therapeutics to improve T-cell responses in this challenging disease.

FAK inhibitors as promising anticancer targets: present and future directions

FAK, a nonreceptor tyrosine kinase, has been recognized as a novel target class for the development of targeted anticancer agents. Overexpression of FAK is a common occurrence in several solid tumors, in which the kinase has been implicated in promoting metastases. Consequently, designing and developing potent FAK inhibitors is becoming an attractive goal, and FAK inhibitors are being recognized as a promising tool in our armamentarium for treating diverse cancers. This review comprehensively summarizes the different classes of synthetically derived compounds that have been reported as potent FAK inhibitors in the last three decades. Finally, the future of FAK-targeting smart drugs that are designed to slow down the emergence of drug resistance is discussed.

Integrin β5 enhances the malignancy of human colorectal cancer by increasing the TGF-β signaling

Increased integrin β5 (ITGB5) expression is associated with the progression and metastasis of several types of cancers. However, whether upregulated ITGB5 expression can act as a prognostic factor for colorectal cancer (CRC) remains controversial. In this study, we aimed to identify the role ITGB5 plays during the pathogenesis of human CRC and explore the underlying molecular mechanism. Here, we show that ITGB5 expression is upregulated in CRC and is significantly associated with exacerbated CRC malignancy and an unfavourable overall survival rate among CRC patients. ITGB5 silencing significantly inhibited the proliferation and invasion of human CRC cell lines (HCT116 and HT29) in vitro and suppressed the growth and metastasis of implanted CRC tumours in vivo. Mechanistically, upregulated ITGB5 expression enhanced transforming growth factor β/Smad signalling and facilitated the epithelial-mesenchymal transition in CRC cells. Together, such findings indicate that ITGB5 acts as an oncogenic factor to enhance the malignancy of CRC and suggest that ITGB5 may be a therapeutic target.

The driving role of the Cdk5/Tln1/FAKS732 axis in cancer cell extravasation dissected by human vascularized microfluidic models

BACKGROUND

Understanding the molecular mechanisms of metastatic dissemination, the leading cause of death in cancer patients, is required to develop novel, effective therapies. Extravasation, an essential rate-limiting process in the metastatic cascade, includes three tightly coordinated steps: cancer cell adhesion to the endothelium, trans-endothelial migration, and early invasion into the secondary site. Focal adhesion proteins, including Tln1 and FAK, regulate the cytoskeleton dynamics: dysregulation of these proteins is often associated with metastatic progression and poor prognosis.

METHODS

Here, we studied the previously unexplored role of these targets in each extravasation step using engineered 3D in vitro models, which recapitulate the physiological vascular niche experienced by cancer cells during hematogenous metastasis.

RESULTS

Human breast cancer and fibrosarcoma cell lines respond to Cdk5/Tln1/FAK axis perturbation, impairing their metastatic potential. Vascular breaching requires actin polymerization-dependent invadopodia formation. Invadopodia generation requires the structural function of FAK and Tln1 rather than their activation through phosphorylation. Our data support that the inhibition of FAKS732 phosphorylation delocalizes ERK from the nucleus, decreasing ERK phosphorylated form. These findings indicate the critical role of these proteins in driving trans-endothelial migration. In fact, both knock-down experiments and chemical inhibition of FAK dramatically reduces lung colonization in vivo and TEM in microfluidic setting. Altogether, these data indicate that engineered 3D in vitro models coupled to in vivo models, genetic, biochemical, and imaging tools represent a powerful weapon to increase our understanding of metastatic progression.

CONCLUSIONS

These findings point to the need for further analyses of previously overlooked phosphorylation sites of FAK, such as the serine 732, and foster the development of new effective antimetastatic treatments targeting late events of the metastatic cascade.

Extracellular Matrices and Cancer-Associated Fibroblasts: Targets for Cancer Diagnosis and Therapy?

Solid cancer progression is dictated by neoplastic cell features and pro-tumoral crosstalks with their microenvironment. Stroma modifications, such as fibroblast activation into cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM) remodeling, are now recognized as critical events for cancer progression and as potential therapeutic or diagnostic targets. The recent appreciation of the key, complex and multiple roles of the ECM in cancer and of the CAF diversity, has revolutionized the field and raised innovative but challenging questions. Here, we rapidly present CAF heterogeneity in link with their specific ECM remodeling features observed in cancer, before developing each of the impacts of such ECM modifications on tumor progression (survival, angiogenesis, pre-metastatic niche, chemoresistance, etc.), and on patient prognosis. Finally, based on preclinical studies and recent results obtained from clinical trials, we highlight key mechanisms or proteins that are, or may be, used as potential therapeutic or diagnostic targets, and we report and discuss benefits, disappointments, or even failures, of recently reported stroma-targeting strategies.

MERTK-Mediated LC3-Associated Phagocytosis (LAP) of Apoptotic Substrates in Blood-Separated Tissues: Retina, Testis, Ovarian Follicles

Timely and efficient elimination of apoptotic substrates, continuously produced during one’s lifespan, is a vital need for all tissues of the body. This task is achieved by cells endowed with phagocytic activity. In blood-separated tissues such as the retina, the testis and the ovaries, the resident cells of epithelial origin as retinal pigmented epithelial cells (RPE), testis Sertoli cells and ovarian granulosa cells (GC) provide phagocytic cleaning of apoptotic cells and cell membranes. Disruption of this process leads to functional ablation as blindness in the retina and compromised fertility in males and females. To ensure the efficient elimination of apoptotic substrates, RPE, Sertoli cells and GC combine various mechanisms allowing maintenance of tissue homeostasis and avoiding acute inflammation, tissue disorganization and functional ablation. In tight cooperation with other phagocytosis receptors, MERTK—a member of the TAM family of receptor tyrosine kinases (RTK)—plays a pivotal role in apoptotic substrate cleaning from the retina, the testis and the ovaries through unconventional autophagy-assisted phagocytosis process LAP (LC3-associated phagocytosis). In this review, we focus on the interplay between TAM RTKs, autophagy-related proteins, LAP, and Toll-like receptors (TLR), as well as the regulatory mechanisms allowing these components to sustain tissue homeostasis and prevent functional ablation of the retina, the testis and the ovaries.

Comprehending the Proteomic Landscape of Ovarian Cancer: A Road to the Discovery of Disease Biomarkers

Despite recent technological advancements allowing the characterization of cancers at a molecular level along with biomarkers for cancer diagnosis, the management of ovarian cancers (OC) remains challenging. Proteins assume functions encoded by the genome and the complete set of proteins, termed the proteome, reflects the health state. Comprehending the circulatory proteomic profiles for OC subtypes, therefore, has the potential to reveal biomarkers with clinical utility concerning early diagnosis or to predict response to specific therapies. Furthermore, characterization of the proteomic landscape of tumor-derived tissue, cell lines, and PDX models has led to the molecular stratification of patient groups, with implications for personalized therapy and management of drug resistance. Here, we review single and multiple marker panels that have been identified through proteomic investigations of patient sera, effusions, and other biospecimens. We discuss their clinical utility and implementation into clinical practice.

Collagen I Fibrous Substrates Modulate the Proliferation and Secretome of Estrogen Receptor-Positive Breast Tumor Cells in a Hormone-Restricted Microenvironment

The fibril orientation of type I collagen has been shown to contribute to tumor invasion and metabolic changes. Yet, there is limited information about its impact on tumor cells' behavior in a restrictive growth environment. Restrictive growth environments are generated by the inhibition of a proliferation stimulus during therapy or as an inflammatory response to suppress tumor expansion. In this study, the impact of a type I collagen matrix orientation and fibrous architecture on cell proliferation and response to estrogen receptor (ER) therapy were examined using estrogen-dependent breast tumor cells (MCF-7 and T-47D) cultured in a hormone-restricted environment. The use of hormone-free culture media, as well as pharmacological inhibitors of ER, Tamoxifen, and Fulvestrant, were investigated as hormone restrictive conditions. Examination of cultures at 72 h showed that tumor cell proliferation was significantly stimulated (1.8-fold) in the absence of hormones on collagen fibrous substrates, but not on polycaprolactone fibrous substrates of equivalent orientation. ER inhibitors did not suppress cell proliferation on collagen fibrous substrates. The examination of reporter cells for ER signaling showed a lack of activity, thus confirming a shift toward an ER-independent proliferation mechanism. Examination of two selective inhibitors of α2β1 and α1β1 integrins showed that cell proliferation is suppressed in the presence of the α2β1 integrin inhibitor only, thereby indicating that the observed changes in tumor cell behavior are caused by a combination of integrin signaling and/or an intrinsic structural motif that is uniquely present in the collagen fibrils. Adjacent coculture studies on collagen substrates showed that tumor cells on collagen can stimulate the proliferation of cells on tissue culture plastic through soluble factors. The magnitude of this effect correlated with the increased surface anisotropy of the substrate. This sensing in fibril orientation was further supported by a differential expression pattern of secreted proteins that were identified on random and aligned orientation substrates. Overall, this study shows a new role for electrospun collagen I fibrous substrates by supporting a shift toward an ER-independent tumor cell proliferation mechanism in ER+ breast tumor cells.

RNF185-AS1 promotes hepatocellular carcinoma progression through targeting miR-221-5p/integrin β5 axis

AIMS

Recently, long noncoding RNAs (lncRNAs) have been reported to play important role in the pathogenesis of various cancers. However, the functions of RNF185-AS1 in hepatocellular carcinoma (HCC) remain unknown.

MATERIALS AND METHODS

The RNF185-AS1 expression in HCC cells and tissues was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The effects of RNF185-AS1 on tumor cell proliferation, migration and invasion were assessed by Cell Counting Kit-8 (CCK8) assay, colony formation assay, transwell assay. The luciferase reporter assay, RNA-binding protein immunoprecipitation assay, qRT-PCR and Western blot were performed to explore and confirm the interaction between RNF185-AS1 and miR-221-5p and integrin β5. The role of RNF185-AS1 in tumor progression was explored through in vivo experiments.

KEY FINDINGS

RNF185-AS1 was highly expressed in HCC tissues and cell lines. High levels of RNF185-AS1 were correlated with advanced TNM stage, distant metastasis and a poorer overall survival rate. RNF185-AS1 knockdown inhibited cell proliferation, migration and invasion. Additionally, RNF185-AS1 acted as a sponge for miR-221-5p and integrin β5 was identified as a target gene of miR-221-5p. Rescue assays showed that miR-221-5p inhibitor or integrin β5 overexpression rescued the function of RNF185-AS1 knockdown on cell proliferation, migration, and invasion. Moreover, we found that RNF185-AS1 knockdown inhibited tumor growth and metastasis.

SIGNIFICANCE

Our study demonstrates that RNF185-AS1 is a new oncogenic lncRNA in HCC and suggests that the RNF185-AS1/miR-221-5p/integrin β5 axis might be a potential therapeutic target for HCC.

Expression correlation attenuates within and between key signaling pathways in chronic kidney disease

BACKGROUND

Compared to the conventional differential expression approach, differential coexpression analysis represents a different yet complementary perspective into diseased transcriptomes. In particular, global loss of transcriptome correlation was previously observed in aging mice, and a most recent study found genetic and environmental perturbations on human subjects tended to cause universal attenuation of transcriptome coherence. While methodological progresses surrounding differential coexpression have helped with research on several human diseases, there has not been an investigation of coexpression disruptions in chronic kidney disease (CKD) yet.

METHODS

RNA-seq was performed on total RNAs of kidney tissue samples from 140 CKD patients. A combination of differential coexpression methods were employed to analyze the transcriptome transition in CKD from the early, mild phase to the late, severe kidney damage phase.

RESULTS

We discovered a global expression correlation attenuation in CKD progression, with pathway Regulation of nuclear SMAD2/3 signaling demonstrating the most remarkable intra-pathway correlation rewiring. Moreover, the pathway Signaling events mediated by focal adhesion kinase displayed significantly weakened crosstalk with seven pathways, including Regulation of nuclear SMAD2/3 signaling. Well-known relevant genes, such as ACTN4, were characterized with widespread correlation disassociation with partners from a wide array of signaling pathways.

CONCLUSIONS

Altogether, our analysis reported a global expression correlation attenuation within and between key signaling pathways in chronic kidney disease, and presented a list of vanishing hub genes and disrupted correlations within and between key signaling pathways, illuminating on the pathophysiological mechanisms of CKD progression.

Focal Adhesion Kinase in Ovarian Cancer: A Potential Therapeutic Target for Platinum and Taxane-Resistant Tumors

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase, which is an essential player in regulating cell migration, invasion, adhesion, proliferation, and survival. Its overexpression and activation have been identified in sixty-eight percent of epithelial ovarian cancer patients and this is significantly associated with higher tumor stage, metastasis, and shorter overall survival of these patients. Most recently, a new role has emerged for FAK in promoting resistance to taxane and platinum-based therapy in ovarian and other cancers. The development of resistance is a complex network of molecular processes that make the identification of a targetable biomarker in platinum and taxane-resistant ovarian cancer a major challenge. FAK overexpression upregulates ALDH and XIAP activity in platinum-resistant and increases CD44, YB1, and MDR-1 activity in taxaneresistant tumors. FAK is therefore now emerging as a prognostically significant candidate in this regard, with mounting evidence from recent successes in preclinical and clinical trials using small molecule FAK inhibitors. This review will summarize the significance and function of FAK in ovarian cancer, and its emerging role in chemotherapeutic resistance. We will discuss the current status of FAK inhibitors in ovarian cancers, their therapeutic competencies and limitations, and further propose that the combination of FAK inhibitors with platinum and taxane-based therapies could be an efficacious approach in chemotherapeutic resistant disease.

Identification and analysis of dysregulated lncRNA and associated ceRNA in the pathogenesis of keloid

Background

Keloid is an excessive fibrosis disease caused by the abnormal proliferation of collagen fibers following trauma. Previous studies have shown that genetic factors have been considered to play important roles in keloid formation. This study is aimed to investigate the regulatory network of messenger RNAs (mRNAs) microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in keloid, and identifying its key biomarkers.

Methods

We performed RNA-seq and miRNA-seq on keloid and normal skin samples. Sequencing datasets were analyzed by bioinformatics. Gene ontology (GO) and pathway analysis presented the characteristics of associated protein-coding genes. Differentially expressed ceRNAs were validated by quantitative reverse transcriptase-PCR (qRT-PCR).

Results

We identified a total of 319 lncRNAs, 1,533 mRNAs and 40 miRNAs as keloid-specific RNAs. Both the GO biological processes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed for 1,219 specific genes with differentially expressed mRNAs. Then, with 509 key lncRNAs, 25 miRNAs, and 94 mRNAs, we constructed a ceRNA network and explored any potential underlying mechanisms. In the regulation of the actin cytokeleton pathway, we validated 2 pairs of ceRNAs EGFR/miR-370-3p/lnc-GLB1L-1 and ITGB5/ miR-204/ lnc-CASP9-3 in another sample size in keloid.

Conclusions

Through RNA-seq and miRNA-seq, we identified keloid-associated lncRNAs, mRNAs and miRNAs, which can be used as potential therapeutic targets and biomarkers for keloid. Our study may lay a foundation for future pathogenesis studies.

Integrin αvβ5 Internalizes Zika Virus during Neural Stem Cells Infection and Provides a Promising Target for Antiviral Therapy

We perform a CRISPR-Cas9 genome-wide screen in glioblastoma stem cells and identify integrin αvβ5 as an internalization factor for Zika virus (ZIKV). Expression of αvβ5 is correlated with ZIKV susceptibility in various cells and tropism in developing human cerebral cortex. A blocking antibody against integrin αvβ5, but not αvβ3, efficiently inhibits ZIKV infection. ZIKV binds to cells but fails to internalize when treated with integrin αvβ5-blocking antibody. αvβ5 directly binds to ZIKV virions and activates focal adhesion kinase, which is required for ZIKV infection. Finally, αvβ5 blocking antibody or two inhibitors, SB273005 and cilengitide, reduces ZIKV infection and alleviates ZIKV-induced pathology in human neural stem cells and in mouse brain. Altogether, our findings identify integrin αvβ5 as an internalization factor for ZIKV, providing a promising therapeutic target, as well as two drug candidates for prophylactic use or treatments for ZIKV infections.

Wang et al. show that Zika virus (ZIKV) uses integrin αvβ5 to infect neural stem cells. ZIKV infection can be inhibited by αvβ5 blocking antibody or inhibitors, SB273005 and cilengitide, in human neural stem cells and in mouse brain, providing drug candidates for prophylactic use or treatments for ZIKV infections.

FAK activity sustains intrinsic and acquired ovarian cancer resistance to platinum chemotherapy

Gene copy number alterations, tumor cell stemness, and the development of platinum chemotherapy resistance contribute to high-grade serous ovarian cancer (HGSOC) recurrence. Stem phenotypes involving Wnt-β-catenin, aldehyde dehydrogenase activities, intrinsic platinum resistance, and tumorsphere formation are here associated with spontaneous gains in Kras, Myc and FAK (KMF) genes in a new aggressive murine model of ovarian cancer. Adhesion-independent FAK signaling sustained KMF and human tumorsphere proliferation as well as resistance to cisplatin cytotoxicity. Platinum-resistant tumorspheres can acquire a dependence on FAK for growth. Accordingly, increased FAK tyrosine phosphorylation was observed within HGSOC patient tumors surviving neo-adjuvant chemotherapy. Combining a FAK inhibitor with platinum overcame chemoresistance and triggered cell apoptosis. FAK transcriptomic analyses across knockout and reconstituted cells identified 135 targets, elevated in HGSOC, that were regulated by FAK activity and β-catenin including Myc, pluripotency and DNA repair genes. These studies reveal an oncogenic FAK signaling role supporting chemoresistance.

The post-abscission midbody is an intracellular signaling organelle that regulates cell proliferation

Once thought to be a remnant of cell division, the midbody (MB) has recently been shown to have roles beyond its primary function of orchestrating abscission. Despite the emerging roles of post-abscission MBs, how MBs accumulate in the cytoplasm and signal to regulate cellular functions remains unknown. Here, we show that extracellular post-abscission MBs can be internalized by interphase cells, where they reside in the cytoplasm as a membrane-bound signaling structure that we have named the MBsome. We demonstrate that MBsomes stimulate cell proliferation and that MBsome formation is a phagocytosis-like process that depends on a phosphatidylserine/integrin complex, driven by actin-rich membrane protrusions. Finally, we show that MBsomes rely on dynamic actin coats to slow lysosomal degradation and propagate their signaling function. In summary, MBsomes may sometimes serve as intracellular organelles that signal via integrin and EGFR-dependent pathways to promote cell proliferation and anchorage-independent growth and survival.

VS-4718 Antagonizes Multidrug Resistance in ABCB1- and ABCG2-Overexpressing Cancer Cells by Inhibiting the Efflux Function of ABC Transporters

Overexpression of ATP-binding cassette (ABC) transporters is one of the most important mechanisms responsible for multi-drug resistance (MDR). VS-4718, a tyrosine kinase inhibitor targeting focal adhesion kinase (FAK) with a potential anticancer effect, is currently evaluated in clinical trials. In this study, we investigated whether VS-4718 could reverse MDR mediated by ABC transporters, including ABCB1, ABCG2, and ABCC1. The results showed that VS-4718 significantly reversed ABCB1- and ABCG2-mediated MDR, but not MDR mediated by ABCC1. Treatment of VS-4718 did not alter the protein level and subcellular localization of ABCB1 or ABCG2. Mechanism studies indicated that the reversal effects of VS-4718 were related to attenuation of the efflux activity of ABCB1 and ABCG2 transporters. ATPase analysis indicated that VS-4718 stimulated the ATPase activity of ABCB1 and ABCG2. Docking study showed that VS-4718 interacted with the substrate-binding sites of both ABCB1 and ABCG2, suggesting that VS-4718 may affect the activity of ABCB1 and ABCG2 competitively. This study provided a novel insight for MDR cancer treatment. It indicated that combination of VS-4718 with antineoplastic drugs could attenuate MDR mediated by ABCB1 or ABCG2 in ABCB1- or ABCG2-overexpressing cancer cells.

The chemopreventive isothiocyanate sulforaphane reduces anoikis resistance and anchorage-independent growth in non-small cell human lung cancer cells

The capacity of cancer cells to resist detachment-induced apoptosis, i.e. anoikis, as well as anchorage-independent growth are crucial prerequisites for tumor metastasis. Therefore, agents interfering these properties may provide novel anti-metastatic strategies. Sulforaphane (SFN), an isothiocyanate found in cruciferous vegetables, is known as a potent chemopreventive agent, but its effect on anoikis resistance has not been investigated. In this study, two non-small cell lung cancer (NSCLC) cell lines, A549 and CL1-5 cells, were treated with SFN under either suspension or adhesion conditions. SFN exhibited more potent cytotoxicity against suspending rather than adherent cancer cells. The selective cytotoxicity was due to the induction of anoikis, as evident by chromatin condensation, Annexin V binding, and activation of the mitochondrial apoptotic pathway. SFN also inhibited NSCLC cell to form spherical colonies, suggesting that anchorage-independent growth was prevented by SFN. Consistently, SFN treatment led to inactivation of FAK and Akt, down-regulation of β-catenin, and up-regulation of the cyclin-dependent kinase inhibitor p21. Because A549 cells with wild-type p53 are more sensitive to SFN than p53-mutant CL1-5 cells, p53 dependency of SFN responses were determined in p53-knockdown A549 cells. Knockdown of p53 attenuated the ability of SNF to inhibit anoikis resistance and sphere formation in A549 cancer cells, suggesting that the presence of p53 in NSCLC cancer cells is involved in the sensitivity to SFN. These results provide new insight into mechanisms underlying the chemopreventive ability of SFN and suggest a potential benefit of SFN to interfere with tumor metastasis.

The mechanical microenvironment regulates ovarian cancer cell morphology, migration, and spheroid disaggregation

There is growing appreciation of the importance of the mechanical properties of the tumor microenvironment on disease progression. However, the role of extracellular matrix (ECM) stiffness and cellular mechanotransduction in epithelial ovarian cancer (EOC) is largely unknown. Here, we investigated the effect of substrate rigidity on various aspects of SKOV3 human EOC cell morphology and migration. Young’s modulus values of normal mouse peritoneum, a principal target tissue for EOC metastasis, were determined by atomic force microscopy (AFM) and hydrogels were fabricated to mimic these values. We find that cell spreading, focal adhesion formation, myosin light chain phosphorylation, and cellular traction forces all increase on stiffer matrices. Substrate rigidity also positively regulates random cell migration and, importantly, directional increases in matrix tension promote SKOV3 cell durotaxis. Matrix rigidity also promotes nuclear translocation of YAP1, an oncogenic transcription factor associated with aggressive metastatic EOC. Furthermore, disaggregation of multicellular EOC spheroids, a behavior associated with dissemination and metastasis, is enhanced by matrix stiffness through a mechanotransduction pathway involving ROCK, actomyosin contractility, and FAK. Finally, this pattern of mechanosensitivity is maintained in highly metastatic SKOV3ip.1 cells. These results establish that the mechanical properties of the tumor microenvironment may play a role in EOC metastasis.

Capn4 contributes to tumor invasion and metastasis in clear cell renal cell carcinoma cells via modulating talin-focal adhesion kinase signaling pathway

Calpain small subunit 1 (Capn4) has been shown to correlate with the metastasis/invasion of clear cell renal cell carcinoma (ccRCC). This study aimed to further elucidate the molecular mechanisms underlying Capn4-mediated ccRCC progression. The mRNA expression levels in ccRCC cells were measured by quantitative real-time PCR. The effects of Capn4 on cell adhesion, invasion, and migration were examined by cell adhesion assay, cell invasion assay, and wound-healing assay, respectively. The protein levels were detected by western blot analysis. The effect of Capn4 on cancer metastasis in vivo was assessed in a nude mice xenograft model. It was found that Capn4 was up-regulated in the ccRCC cells, and Capn4 overexpression suppressed cell adhesion activity and increased cell invasion and migration in 786-O cells, while Capn4 silencing increased cell adhesion activity and impaired the invasion and migration ability of Caki-1 cells. Capn4 overexpression also increased the protein level of cleaved talin in 786-O cells, while Capn4 silencing decreased the protein level of cleaved talin in Caki-1 cells. The focal adhesion kinase (FAK)/AKT/MAPK signaling was activated by Capn4 overexpression in 786-O cells, and was inhibited by Capn4 down-regulation in Caki-1 cells. Capn4 overexpression increased the protein levels of matrix metalloproteinase 2 (MMP-2), vimentin, N-cadherin, and down-regulated E-cadherin in 786-O cells, while Capn4 silencing decreased the protein levels of MMP-2, vimentin, N-cadherin, and up-regulated E-cadherin in Caki-1 cells. Capn4 also promoted cancer metastasis in the in vivo nude mice xenograft model. Our results implicate the functional role of Capn4 in ccRCC invasion and migration, which may contribute to cancer metastasis in ccRCC.

CCL2/CCL5 secreted by the stroma induce IL-6/PYK2 dependent chemoresistance in ovarian cancer

BACKGROUND

Minimal residual disease is the main issue of advanced ovarian cancer treatment. According to the literature and previous results, we hypothesized that Mesenchymal Stromal Cells (MSC) could support this minimal residual disease by protecting ovarian cancer cells (OCC) from chemotherapy. In vitro study confirmed that MSC could induce OCC chemoresistance without contact using transwell setting. Further experiments showed that this induced chemoresistance was dependent on IL-6 OCC stimulation.

METHODS

We combined meticulous in vitro profiling and tumor xenograft models to study the role of IL-6 in MSC/OCC intereactions.

RESULTS

We demonstrated that Tocilizumab® (anti-IL-6R therapy) in association with chemotherapy significantly reduced the peritoneal carcinosis index (PCI) than chemotherapy alone in mice xenografted with OCCs+MSCs. Further experiments showed that CCL2 and CCL5 are released by MSC in transwell co-culture and induce OCCs IL-6 secretion and chemoresistance. Finally, we found that IL-6 induced chemoresistance was dependent on PYK2 phosphorylation.

CONCLUSIONS

These findings highlight the potential key role of the stroma in protecting minimal residual disease from chemotherapy, thus favoring recurrences. Future clinical trials targeting stroma could use anti-IL-6 therapy in association with chemotherapy.

Integrin-β5, a miR-185-targeted gene, promotes hepatocellular carcinoma tumorigenesis by regulating β-catenin stability

Background

The tumour microenvironment is essential for cancer progress and metastasis. Integrin-β5 (ITGB5), a member of the integrin family, has been implicated to mediate the interactions of cells with the extracellular matrix (ECM) and promote tumorigenesis in several malignancies. However, the role of ITGB5 in hepatocellular carcinoma (HCC) is still unknown.

Methods

The biological function of ITGB5 in HCC was investigated using migration, colony formation assays. The potential molecular mechanism of ITGB5 in regulating HCC tumorigenesis and β-catenin stabilization was investigated by western blotting, co-immunoprecipitation and ubiquitination assays. The expression level of ITGB5 mediated by miR-185 was confirmed by bioinformatic analysis, luciferase assay. The clinical significance of ITGB5 was based on human tissue microarray (TMA) analysis.

Results

Here, we found that the expression of ITGB5 is increased in HCC tissues. Elevated ITGB5 markedly facilitates HCC cell migration and tumorigenesis in vitro and in vivo. Further mechanistic studies revealed that ITGB5, as a partner of β-catenin, directly interacts with β-catenin and inhibits its degradation, thus leading to WNT/β-catenin activity. Subsequently, we also found that ITGB5 is a direct targeted gene of miR-185. The downregulation of miR-185 in HCC cells promotes an increase in ITGB5. An additional increase of ITGB5 is associated with β-catenin upregulation and a miR-185 decrease in HCC tissues.

Conclusions

Our data reveal that the miR-185-ITGB5-β-catenin pathway plays an important role in HCC tumorigenesis, and ITGB5 may be a promising specific target for HCC therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0691-9) contains supplementary material, which is available to authorized users.

The interplay between extracellular matrix remodelling and kinase signalling in cancer progression and metastasis

The extracellular matrix (ECM) is a master regulator of cellular phenotype and behaviour. It plays a crucial role in both normal tissue homeostasis and complex diseases such as cancer. The interplay between the intrinsic factors of cancer cells themselves, including their genotype and signalling networks; and the extrinsic factors of the tumour stroma, such as the ECM and ECM remodelling; together determine the fate and behaviour of cancer cells. As a consequence, tumour progression, metastatic spread and response to therapy are ultimately controlled by ECM-driven fine-tuning of intracellular kinase signalling. The ability to target and uncouple this interaction presents an emerging and promising potential in the treatment of cancer.

Lycopene reduces ovarian tumor growth and intraperitoneal metastatic load

Mutagens like oxidants cause lesions in the DNA of ovarian and fallopian tube epithelial cells, resulting in neoplastic transformation. Reduced exposure of surface epithelia to oxidative stress may prevent the onset or reduce the growth of ovarian cancer. Lycopene is well-known for its excellent antioxidant properties. In this study, the potential of lycopene in the prevention and treatment of ovarian cancer was investigated using an intraperitoneal animal model. Lycopene prevention significantly reduced the metastatic load of ovarian cancer-bearing mice, whereas treatment of already established ovarian tumors with lycopene significantly diminished the tumor burden. Lycopene treatment synergistically enhanced anti-tumorigenic effects of paclitaxel and carboplatin. Immunostaining of tumor and metastatic tissues for Ki67 revealed that lycopene reduced the number of proliferating cancer cells. Lycopene decreased the expression of the ovarian cancer biomarker, CA125. The anti-metastatic and anti-proliferative effects were accompanied by down-regulated expression of ITGA5, ITGB1, MMP9, FAK, ILK and EMT markers, decreased protein expression of integrin α5 and reduced activation of MAPK. These findings indicate that lycopene interferes with mechanisms involved in the development and progression of ovarian cancer and that its preventive and therapeutic use, combined with chemotherapeutics, reduces the tumor and metastatic burden of ovarian cancer in vivo.

p14ARF interacts with the focal adhesion kinase and protects cells from anoikis

The ARF protein functions as an important sensor of hyper-proliferative stimuli restricting cell proliferation through both p53-dependent and -independent pathways. Although to date the majority of studies on ARF have focused on its anti-proliferative role, few studies have addressed whether ARF may also have pro-survival functions. Here we show for the first time that during the process of adhesion and spreading ARF re-localizes to sites of active actin polymerization and to focal adhesion points where it interacts with the phosphorylated focal adhesion kinase. In line with its recruitment to focal adhesions, we observe that hampering ARF function in cancer cells leads to gross defects in cytoskeleton organization resulting in apoptosis through a mechanism dependent on the Death-Associated Protein Kinase. Our data uncover a novel function for p14ARF in protecting cells from anoikis that may reflect its role in anchorage independence, a hallmark of malignant tumor cells.

Targeting glutamine metabolism and the focal adhesion kinase additively inhibits the mammalian target of the rapamycin pathway in spheroid cancer stem-like properties of ovarian clear cell carcinoma in vitro

Ovarian cancer is one of the leading causes of death in the world, which is linked to its resistance to chemotherapy. Strategies to overcome chemoresistance have been keenly investigated. Culturing cancer cells in suspension, which results in formation of spheroids, is a more accurate reflection of clinical cancer behavior in vitro than conventional adherent cultures. By performing RNA-seq analysis, we found that the focal adhesion pathway was essential in spheroids. The phosphorylation of focal adhesion kinase (FAK) was increased in spheroids compared to adherent cells, and inhibition of FAK in spheroids resulted in inhibition of the downstream mammalian target of the rapamycin (mTOR) pathway in ovarian clear cell carcinomas. This result also suggested that only using a FAK inhibitor might have limitations because the phosphorylation level of FAK could not be reduced to the level in adherent cells, and it appeared that some combination therapies might be necessary. We previously reported that glutamine and glutamate concentrations were higher in spheroids than adherent cells, and we investigated a synergistic effect targeting glutamine metabolism with FAK inhibition on the mTOR pathway. The combination of AOA, a pan-transaminase inhibitor, and PF 573228, a FAK inhibitor, additively inhibited the mTOR pathway in spheroids from ovarian clear cell carcinomas. Our in vitro study proposed a rationale for the positive and negative effects of using FAK inhibitors in ovarian clear cell carcinomas and suggested that targeting glutamine metabolism could overcome the limitation of FAK inhibitors by additively inhibiting the mTOR pathway.

Inhibition of the integrin/FAK signaling axis and c-Myc synergistically disrupts ovarian cancer malignancy

Integrins, a family of heterodimeric receptors for extracellular matrix, are promising therapeutic targets for ovarian cancer, particularly high-grade serous-type (HGSOC), as they drive tumor cell attachment, migration, proliferation and survival by activating focal adhesion kinase (FAK)-dependent signaling. Owing to the potential off-target effects of FAK inhibitors, disruption of the integrin signaling axis remains to be a challenge. Here, we tackled this barrier by screening for inhibitors being functionally cooperative with small-molecule VS-6063, a phase II FAK inhibitor. From this screening, JQ1, a potent inhibitor of Myc oncogenic network, emerged as the most robust collaborator. Treatment with a combination of VS-6063 and JQ1 synergistically caused an arrest of tumor cells at the G2/M phase and a decrease in the XIAP-linked cell survival. Our subsequent mechanistic analyses indicate that this functional cooperation was strongly associated with the concomitant disruption of activation or expression of FAK and c-Myc as well as their downstream signaling through the PI3K/Akt pathway. In line with these observations, we detected a strong co-amplification or upregulation at genomic or protein level for FAK and c-Myc in a large portion of primary tumors in the TCGA or a local HGSOC patient cohort. Taken together, our results suggest that the integrin–FAK signaling axis and c-Myc synergistically drive cell proliferation, survival and oncogenic potential in HGSOC. As such, our study provides key genetic, functional and signaling bases for the small-molecule-based co-targeting of these two distinct oncogenic drivers as a new line of targeted therapy against human ovarian cancer.

Kaempferol Inhibits the Invasion and Migration of Renal Cancer Cells through the Downregulation of AKT and FAK Pathways

Kaempferol, which is isolated from several natural plants, is a polyphenol belonging to the subgroup of flavonoids. Kaempferol exhibits various pharmacological activities, including anti-inflammatory, antioxidant, antimicrobial, and anticancer activities. In this study, kaempferol can significantly inhibit the invasion and migration of 786-O renal cell carcinoma (RCC) without cytotoxicity. We examined the potential mechanisms underlying its anti-invasive activities on 786-O RCC cells. Western blot was performed, and the results showed that kaempferol attenuates the manifestation of metalloproteinase-2 (MMP-2) protein and activity. The inhibitive effect of kaempferol on MMP-2 may be attributed to the downregulation of phosphorylation of Akt and focal adhesion kinase (FAK). By examining the SCID mice model, we found that kaempferol can safely inhibit the metastasis of the 786-O RCC cells into the lungs by about 87.4% as compared to vehicle treated control animals. In addition, the lung tumor masses of mice pretreated with 2-10 mg/kg kaempferol were reduced about twofold to fourfold. These data suggested that kaempferol can play a promising role in tumor prevention and cancer metastasis inhibition.

Plasticity of Cancer Cell Invasion-Mechanisms and Implications for Therapy

Cancer cell migration is a plastic and adaptive process integrating cytoskeletal dynamics, cell-extracellular matrix and cell-cell adhesion, as well as tissue remodeling. In response to molecular and physical microenvironmental cues during metastatic dissemination, cancer cells exploit a versatile repertoire of invasion and dissemination strategies, including collective and single-cell migration programs. This diversity generates molecular and physical heterogeneity of migration mechanisms and metastatic routes, and provides a basis for adaptation in response to microenvironmental and therapeutic challenge. We here summarize how cytoskeletal dynamics, protease systems, cell-matrix and cell-cell adhesion pathways control cancer cell invasion programs, and how reciprocal interaction of tumor cells with the microenvironment contributes to plasticity of invasion and dissemination strategies. We discuss the potential and future implications of predicted "antimigration" therapies that target cytoskeletal dynamics, adhesion, and protease systems to interfere with metastatic dissemination, and the options for integrating antimigration therapy into the spectrum of targeted molecular therapies.

Molecular Pathways: Endothelial Cell FAK-A Target for Cancer Treatment

The nonreceptor protein tyrosine kinase, focal adhesion kinase (FAK, also known as PTK2), is a key mediator of signal transduction downstream of integrins and growth factor receptors in a variety of cells, including endothelial cells. FAK is upregulated in several advanced-stage solid tumors and has been described to promote tumor progression and metastasis through effects on both tumor cells and stromal cells. This observation has led to the development of several FAK inhibitors, some of which have entered clinical trials (GSK2256098, VS-4718, VS-6062, VS-6063, and BI853520). Resistance to chemotherapy is a serious limitation of cancer treatment and, until recently, most studies were restricted to tumor cells, excluding the possible roles performed by the tumor microenvironment. A recent report identified endothelial cell FAK (EC-FAK) as a major regulator of chemosensitivity. By dysregulating endothelial cell-derived paracrine (also known as angiocrine) signals, loss of FAK solely in the endothelial cell compartment is able to induce chemosensitization to DNA-damaging therapies in the malignant cell compartment and thereby reduce tumor growth. Herein, we summarize the roles of EC-FAK in cancer and development and review the status of FAK-targeting anticancer strategies. Clin Cancer Res; 22(15); 3718-24. ©2016 AACR.

FAK Expression, Not Kinase Activity, Is a Key Mediator of Thyroid Tumorigenesis and Protumorigenic Processes

There are limited therapy options for advanced thyroid cancer, including papillary and anaplastic thyroid cancer (PTC and ATC). Focal adhesion kinase (FAK) regulates cell signaling by functioning as a scaffold and kinase. Previously, we demonstrated that FAK is overexpressed and activated in thyroid cancer cells and human PTC clinical specimens. However, it remains unclear whether patients with advanced thyroid cancer will benefit from FAK inhibition. Therefore, the dual functions of FAK in mediating protumorigenic processes and thyroid tumorigenesis were investigated. Evidence here shows that FAK expression predominantly regulates thyroid cancer cell growth, viability, and anchorage-independent growth. FAK inhibition, with PF-562,271 treatment, modestly reduced tumor volumes, while FAK depletion, through shRNA knockdown, significantly reduced tumor volumes in vivo A role for FAK expression in tumor establishment was demonstrated in a model of PTC, where FAK knockdown tumors did not develop. FAK depletion also led to a significant decrease in overall metastatic burden. Interestingly, pretreatment with a FAK inhibitor resulted in a paradoxical increase in metastasis in a model of ATC, but decreased metastasis in a model of PTC. These data provide the first evidence that FAK expression is critical for the regulation of thyroid tumorigenic functions.

IMPLICATIONS

This study demonstrates that FAK expression, but not kinase activity alone, predominantly mediates thyroid tumor growth and metastasis, indicating that targeting the scaffolding function(s) of FAK may be an important therapeutic strategy for advanced thyroid cancer, as well as other FAK-dependent tumors. Mol Cancer Res; 14(9); 869-82. ©2016 AACR.

3D matrix-based cell cultures: Automated analysis of tumor cell survival and proliferation

Three-dimensional ex vivo cell cultures mimic physiological in vivo growth conditions thereby significantly contributing to our understanding of tumor cell growth and survival, therapy resistance and identification of novel potent cancer targets. In the present study, we describe advanced three-dimensional cell culture methodology for investigating cellular survival and proliferation in human carcinoma cells after cancer therapy including molecular therapeutics. Single cells are embedded into laminin-rich extracellular matrix and can be treated with cytotoxic drugs, ionizing or UV radiation or any other substance of interest when consolidated and approximating in vivo morphology. Subsequently, cells are allowed to grow for automated determination of clonogenic survival (colony number) or proliferation (colony size). The entire protocol of 3D cell plating takes ~1 h working time and pursues for ~7 days before evaluation. This newly developed method broadens the spectrum of exploration of malignant tumors and other diseases and enables the obtainment of more reliable data on cancer treatment efficacy.

The traditional Tibetan medicine Yukyung Karne exhibits a potent anti-metastatic activity by inhibiting the epithelial to mesenchymal transition and cell migration

BACKGROUND

In Traditional Tibetan medicine, Yukyung Karne has been used for the treatment of ovarian cancer. Though Yukyung Karne has been reported to be clinically effective, the molecular mechanism of its anti-metstatic action remains elusive.

METHODS

The cytotoxic property of Yukyung Karne was evaluated by crystal violet staining while its ability to induce ceramide production was analyzed by sphingomyelinase assay. The anti-metastatic property was investigated using adhesion, invasion, migration and colony formation assays. The effect of Yukyung Karne on the expression of extracellular matrix components, and epithelial and mesenchymal markers were evaluated by confocal microscopy and western blotting.

RESULTS

Yukyung Karne exhibited a strong anti-metastatic property by significantly reducing the invasion, migration and colony formation ability of ovarian cancer cells. Besides it inhibited the levels of biomarkers involved in epithelial to mesenchymal transition such as down-regulation of vimentin and N-cadherin and up-regulation of epithelial E-cadherin. Yukyung Karne also induced the neutral sphingomyelinase II (nSMNaseII) enzyme activity that is known to hydrolyze sphingomyelins into pro-apoptotic intracellular molecule ceramide.

CONCLUSIONS

The study provides some compelling evidences supporting the anti-metastatic potential of Yukyung Karne which strongly suggests its possible usage as a promising alternative medicine. Thus, Yukyung Karne may be used as an anticancer and anti-metastatic agent along with other conventional anticancer therapeutics to increase their efficacy.

FAK activity protects nucleostemin in facilitating breast cancer spheroid and tumor growth

Introduction

Focal adhesion kinase (FAK) controls cell growth and survival downstream of integrin-matrix receptors. Upon adhesion loss or FAK inhibition, FAK can translocate to the nucleus. The nucleolus is a non-membrane nuclear structure that regulates ribosome biogenesis and cell proliferation. Nucleostemin (NS), a nucleolar-localized protein, modulates cell cycle progression, stemness, and three-dimensional tumor spheroid formation. The signaling pathways that regulate NS levels in tumors remain undefined.

Methods

Human breast carcinoma cells were evaluated for growth in culture (adherent and anchorage-independent spheroid) and as orthotopic tumors. FAK signaling was evaluated by pharmacological FAK inhibitor addition (PF-271, IC50 ~ 0.1 μM) and by small hairpin RNA (shRNA) knockdown followed by re-expression of FAK wildtype (WT) or a kinase-dead (KD, K454R) FAK point mutant. Immunoblotting was used to evaluate FAK, NS, nucleolar phosphoprotein B23, and nucleolin levels. Total and phosphospecific antibody imunoblotting were used to detect changes in FAK, Akt kinase (Akt also known as protein kinase B), and 4E-binding protein 1 (4E-BP1) phosphorylation, a translation repressor protein and target of the mammalian target of rapamycin (mTOR) complex. Immunohistochemical, co-immunoprecipitation, and cellular fractionation analyses were used to evaluate FAK association with nucleoli.

Results

Pharmacological (0.1 μM PF-271) or genetic inhibition of FAK activity prevents MDA-MB-231 and 4T1L breast carcinoma growth as spheroids and as orthotopic tumors. FAK inhibition triggers proteasome-mediated decreased NS levels but no changes in other nucleolar proteins such as B23 (nucleophosmin) or nucleolin. Active FAK was associated with purified nucleoli of anchorage-independent cells and present within nucleoli of human invasive ductal carcinoma tumor samples. FAK co-immunoprecipitated with B23 that binds NS and a complex between FAK, NS, Akt, and mTOR was detected. Constitutively-active Akt kinase promoted tumor spheroid growth, stabilized NS levels, and promoted pS65 4E-BP1 phosphorylation in the presence of inhibited FAK. Rapamycin lowered NS levels and inhibited pS65 4E-BP1 phosphorylation in cells with activated Akt-mTOR signaling.

Conclusions

FAK signaling occurs in the nucleolus, active FAK protects NS, and Akt-mTOR pathway regulates NS protein stability needed for breast carcinoma spheroid and tumor growth.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0551-x) contains supplementary material, which is available to authorized users.

Frequent Loss of NISCH Promotes Tumor Proliferation and Invasion in Ovarian Cancer via Inhibiting the FAK Signal Pathway

NISCH encodes the imidazoline receptor Nischarin and is a known tumor suppressor in many human malignancies; however, its roles in ovarian cancer are still largely unknown. Here, we aim to investigate the biologic functions of NISCH in ovarian cancer. We found that NISCH was significantly downregulated, which correlated considerably with advanced tumor stage, poor differentiation, lymph node metastasis, and the serous/mucinous subtypes in a panel of ovarian cancer tissues. Moreover, NISCH gene silencing was mainly the product of promoter hypermethylation, which could be reversed by treatment with 5-aza-dC. In vitro, NISCH overexpression suppressed cell proliferation and colony formation by hindering cell-cycle progression, whereas the opposite was observed in NISCH knockdown counterparts. In vivo, abundant NISCH expression hindered the growth of HO8910 xenografts, whereas NISCH knockdown accelerated the growth of SKOV3 xenografts. In addition, NISCH significantly attenuated cell invasion by inhibiting the phosphorylation of FAK and ERK, which could be neutralized by PF-562271 (a FAK/Pyk2 inhibitor). Accordingly, NISCH knockdown xenografts exhibited increased peritoneal/pelvic metastases that were not present in counterparts treated with PF-562271. Furthermore, NISCH expression in primary ovarian cancer cells predicted a cellular resistance to PF-562271. In conclusion, we showed that NISCH was frequently silenced by promoter hypermethylation in human ovarian cancer. NISCH manipulated cellular proliferation and invasion by arresting cell cycle and inhibiting the FAK signal. Our findings revealed the biologic functions of NISCH in ovarian cancer, and might be useful for treating patients with aberrant expression of NISCH.

An oncogenic role of Agrin in regulating focal adhesion integrity in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. The identity and role of cell surface molecules driving complex biological events leading to HCC progression are poorly understood, hence representing major lacunae in HCC therapies. Here, combining SILAC quantitative proteomics and biochemical approaches, we uncover a critical oncogenic role of Agrin, which is overexpressed and secreted in HCC. Agrin enhances cellular proliferation, migration and oncogenic signalling. Mechanistically, Agrin’s extracellular matrix sensor activity provides oncogenic cues to regulate Arp2/3-dependent ruffling, invadopodia formation and epithelial–mesenchymal transition through sustained focal adhesion integrity that drives liver tumorigenesis. Furthermore, Agrin signalling through Lrp4-muscle-specific tyrosine kinase (MuSK) forms a critical oncogenic axis. Importantly, antibodies targeting Agrin reduced oncogenic signalling and tumour growth in vivo. Together, we demonstrate that Agrin is frequently upregulated and important for oncogenic property of HCC, and is an attractive target for antibody therapy.

The proteoglycan Agrin is known to be expressed in neurons and muscle and to bind ECM protein laminin. Here the authors report that Agrin promotes hepatocellular carcinoma by stimulating proliferation, decreasing focal adhesion, increasing invasiveness and promoting an epithelial-to-mesenchymal transition.

Understanding the roles of FAK in cancer: inhibitors, genetic models, and new insights

Focal adhesion kinase (FAK) is a protein tyrosine kinase that regulates cellular adhesion, motility, proliferation and survival in various types of cells. Interestingly, FAK is activated and/or overexpressed in advanced cancers, and promotes cancer progression and metastasis. For this reason, FAK became a potential therapeutic target in cancer, and small molecule FAK inhibitors have been developed and are being tested in clinical phase trials. These inhibitors have demonstrated to be effective by inducing tumor cell apoptosis in addition to reducing metastasis and angiogenesis. Furthermore, several genetic FAK mouse models have made advancements in understanding the specific role of FAK both in tumors and in the tumor environment. In this review, we discuss FAK inhibitors as well as genetic mouse models to provide mechanistic insights into FAK signaling and its potential in cancer therapy.

FERM domain-containing protein FRMD5 regulates cell motility via binding to integrin β5 subunit and ROCK1

FRMD5 is a novel FERM domain-containing protein depicted in tumor progression. However, the mechanisms underlying FRMD5 inhibition of cell migration is largely unknown. Here, we show that FRMD5 regulates cell migration by interacting with integrin β5 cytoplasmic tail and ROCK1 in human lung cancer cells. FRMD5 promotes cell-matrix adhesion and cell spreading on vitronectin, and thus inhibits cell migration. Furthermore, FRMD5 interacts with ROCK1 and inhibits its activation that leads to the inhibition of myosin light chain phosphorylation and the actin stress fiber formation. Taken together, these findings demonstrate that the putative tumor suppressive protein FRMD5 regulates tumor cell motility via a dual pathway involving FRMD5 binding to integrin β5 tail and to ROCK1.

FAK in cancer: mechanistic findings and clinical applications

Focal adhesion kinase (FAK) is a cytoplasmic protein tyrosine kinase that is overexpressed and activated in several advanced-stage solid cancers. FAK promotes tumour progression and metastasis through effects on cancer cells, as well as stromal cells of the tumour microenvironment. The kinase-dependent and kinase-independent functions of FAK control cell movement, invasion, survival, gene expression and cancer stem cell self-renewal. Small molecule FAK inhibitors decrease tumour growth and metastasis in several preclinical models and have initial clinical activity in patients with limited adverse events. In this Review, we discuss FAK signalling effects on both tumour and stromal cell biology that provide rationale and support for future therapeutic opportunities.