Focal Adhesion Kinase Inhibitor Research Articles

Diosmin reduces the stability of Snail and Cyclin D1 by targeting FAK to inhibit NSCLC progression

BackgroundIn different tumours, focal adhesion kinase (FAK), a nonreceptor tyrosine kinase, is upregulated and hence, it represents a promising target for cancer therapy. However, the development of FAK kinase inhibitors has faced a number of challenges. It is therefore imperative that new, effective FAK kinase inhibitors be identified promptly. MethodsSmall molecules that target FAK were identified through molecular docking and validated through surface plasmon resonance (SPR) and cell thermal shift analysis. We investigated the pharmacological effects of FAK kinase inhibitors using CCK-8, colony formation, EdU, and Transwell assays and cell cycle analysis. The molecular mechanism was determined via methods such as coimmunoprecipitation, RNA pull-down and RNA immunoprecipitation. ResultsHere, we confirmed that diosmin (Dio) is an inhibitor of FAK and demonstrated its anti-proliferative and anti-metastatic effects in lung adenocarcinoma. Mechanistically, Dio inhibited tumour proliferation and metastasis by impeding the catalytic activity of FAK. Dio activated the ubiquitin proteasome pathway to induce Cyclin D1 degradation, while inhibiting tumour proliferation and reversing the epithelial mesenchymal transition (EMT) process by reducing the mRNA stability of Snail, thereby inhibiting cancer metastasis. In addition, the inhibitory effect of Dio on lung adenocarcinoma was validated in a mouse xenograft model. ConclusionThese results support the tumour-promoting role of FAK in lung adenocarcinoma by stabilizing Cyclin D1 and Snail and suggest that Dio is a promising candidate for FAK inhibition.

Clotting promotes glioma growth and infiltration through activation of focal adhesion kinase.

The tumor architecture of high-grade gliomas is shaped by tumor cell necrosis, invasive growth and the leakage of a fibrin-rich edema from poorly organized tumor blood vessels. Here, we demonstrate a marked upregulation of clot formation in the interstitial spaces of tumor tissues from patients with glioblastoma while tumor-free brain is essentially devoid of fibrin. The accumulation of fibrin in tumor interstitial spaces is functionally relevant as we demonstrate increased infiltration and growth of primary glioblastoma cells after embedding in a 3-dimensional matrix made of fibrin ex vivo. Additionally, we detected accelerated tumor growth after implanting glioblastoma cells together with clotted plasma in brains of immune deficient mice while glioblastoma development in clotting-deficient hemophilia mice was delayed. Glioblastoma growth correlated with the outgrowth of invadopodia and their adhesive interactions with the 3-dimensional clot matrix, which was mediated by integrins β1 and β3 and their common downstream target focal adhesion kinase (FAK). Knocking down FAK with CRISPR Cas9 caused an upregulation of p21/p27 cell cycle inhibitors, strong growth inhibition in cultured glioblastoma cells and sustained anti-tumorigenic effects in orthotopic glioblastoma xenografts in vivo. These results go hand in hand with genomic data from The Cancer Genome Atlas that indicate increased clotting activity and reduced patient survival in glioma subgroups with high integrin β1 and β3 expression. We therefore conclude that clotting in glioma interstitial spaces provides tumor cells with a potent proliferative stimulus that can be reversed by targeting the adhesive machinery of glioblastoma cells via inhibition of FAK.

EXTH-41. COMBINATION TREATMENT WITH RAF/MEK AND FAK INHIBITION ENHANCES TUMOR GROWTH INHIBITION IN MENINGIOMA

Abstract BACKGROUND Patients with meningiomas who have progressed after multimodal treatments face a significant shortage of viable therapeutic options. Recent advancements in the molecular understanding of meningiomas have identified the FAK and RAF/MEK signaling pathways as potential promising targets for progressive meningiomas. METHODS In vitro, we tested two human meningioma cell lines, IOMM-Lee (NF2 wild-type and CDKN2A loss) and CH157-MN (NF2 mutant). The cells were plated in Matrigel-coated wells, treated with defactinib (FAK inhibitor), VS-6766 (RAF/MEK inhibitor, avutometinib) and the combination over a 7-day period and assessed for cell viability using the CellTiter-Glo 3D assay. In vivo, we tested the efficacy of the FAK inhibitor VS-4718 (possessing favorable pharmacokinetic properties in mice) and RAF/MEK inhibitor VS-6766, both given daily via oral gavage, in athymic nude mice bearing IOMM-Lee or CH157-MN tumors. RESULTS In the matrigel assay, VS-6766 suppressed IOMM-Lee and CH157-MN cells in a dose dependent manner. The drug combination was mostly additive in IOMM-Lee cells. However, CH157-MN cells showed a strong synergistic response across all drug concentrations tested. In the IOMM-Lee flank tumor model, VS-4718 alone had no effect, while VS-6766 alone or in combination significantly reduced tumor growth and extended median survival from 25 days to 47 days (p < 0.05). In the CH157 flank tumor model, VS-4718 monotherapy did not affect tumor growth or survival, but VS-6766 monotherapy slowed tumor growth and increased median survival from 10 days to 31 days (p < 0.001). Combining both drugs further reduced tumor growth and extended median survival to 42 days (p < 0.001). CONCLUSION Treatment with FAK and RAF/MEK inhibitors showed synergistic or combination effects in the NF2 mutant CH157-MN model in vitro and in vivo. RAF/MEK inhibitor monotherapy was effective for the IOMM-Lee model (NF2 wild-type), without clear benefit of combining with the FAK inhibitor. Investigations in intracranial tumor models are underway.

EXTH-62. FOCAL ADHESION KINASE (FAK) IN CHROMOSOME 8 GAIN-ASSOCIATED MALIGNANT PERIPHERAL NERVE SHEATH TUMORS (MPNST)

Abstract OBJECTIVES Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas often associated with Neurofibromatosis type 1 (NF1), a genetic syndrome driven by overactivation of the RAS pathway. MEK inhibitors (MEKi) target downstream components of the RAS pathway and have been approved for NF1 patients with plexiform neurofibromas (PN). However, MPNST often develop resistance to MEKi. Our lab recently discovered the critical role of chromosome 8 (Chr8) genes in MPNST. The Chr8 gene, protein tyrosine kinase 2 (PTK2), also known as focal adhesion kinase (FAK) is overexpressed in multiple cancers, suggesting its importance in tumor progression. In this study, we aim to evaluate FAK as a therapeutic target for MPNST and investigate the FAKi and RAF/MEKi combination. METHODS A CRISPR gRNA screen was used to identify Chr8 genes involved in MPNST survival. The effect of FAK shRNA knockdown and a FAK inhibitor (FAKi), alone or combined with a MEKi, in MPNST cells was assessed using IncuCyte proliferation assays and multiple murine models. RESULTS The CRISPR gRNA screen identified 57 genes on Chr8 important for MPNST cell survival, including PTK2/FAK. Knockdown of FAK by shRNA in MPNST inhibited cell proliferation in vitro and reduced tumorigenesis in vivo. Consistently, the FAKi defactinib significantly inhibited the proliferation of MPNST (IC50-values: 1.72-4.65μM). Moreover, the defactinib/avutometinib combination was synergistic in vitro and the combination of FAKi with RAF/MEKi reduced tumor growth more that either drug alone in Chr8-gain MPNST PDX models. Avutometinib induced compensatory activation of FAK, while defactinib/avutometinib combination decreased phosphorylation of FAK, ERK1/2 and STAT3, and augmented cleavage of Caspase-3 and PARP-1, shown using the WES protein simple system. CONCLUSION These results demonstrate the potential therapeutic efficacy of FAK inhibitors, both alone and in combination with RAF/MEKi, for the treatment of MPNST.

Advanced Computational Pipeline for FAK Inhibitor Discovery: Combining Multiple Docking Methods with MD and QSAR for Cancer Therapy

Synthetic lethality, involving the simultaneous deactivation of two genes, disrupts cellular functions or induces cell death. This study examines its role in cancer, focusing on focal adhesion kinase and Neurofibromin 2. Inhibiting FAK, crucial for synthetic lethality with NF2/Merlin, offers significant cancer treatment potential. No FAK inhibitor has been clinically approved, underscoring the need for new, effective inhibitors. The small-molecule FAK inhibitors identified in this study show promise, with SP docking, IFD, QPLD, and MD simulations revealing intricate interactions. Based on the comprehensive analysis, the MM/GBSA scores from SP docking for amprenavir, bosutinib, ferric derisomaltose, flavin adenine dinucleotide, lactulose, and tafluprost were determined as −72.81, −71.84, −76.70, −69.09, −74.86, and −65.77 kcal/mol, respectively. The MMGBSA results following IFD docking MD identified the top-performing compounds with scores of −84.0518, −75.2591, −71.8943, −84.2638, −56.3019, and −75.3873 kcal/mol, respectively. The MMGBSA results from QPLD docking MD identified the leading compounds with scores of −77.8486, −69.5773, −71.9171, N/A, −62.5716, and −66.8067 kcal/mol, respectively. In conclusion, based on the MMGBSA scores obtained using the three docking methods and the 100 ns MD simulations, and considering the combined evaluation of these methods, amprenavir, ferric derisomaltose, and bosutinib are proposed as the most promising candidates.

Focal adhesion kinase inhibitors as maintenance therapy in a homologous recombination repair proficient high-grade serous ovarian cancer murine model

Focal adhesion kinase inhibitors as maintenance therapy in a homologous recombination repair proficient high-grade serous ovarian cancer murine model

Pre-clinical efficacy of RAF/MEK clamp avutometinib in combination with FAK inhibition for low-grade serous ovarian cancer

Pre-clinical efficacy of RAF/MEK clamp avutometinib in combination with FAK inhibition for low-grade serous ovarian cancer

Kinin Receptors B1 and B2 Mediate Breast Cancer Cell Migration and Invasion by Activating the FAK-Src Axis.

Kinin receptors B1 and B2 are involved in migration and invasion in gastric, glioma, and cervical cancer cells, among others. However, the role of kinin receptors in breast cancer cells has been poorly studied. We aimed to reveal the impact of B1 and B2 receptors on migration and invasion in breast cancer cells and demonstrate their capacity to modulate in vivo tumor growth. MDA-MB-231, MCF-7, and T47D cells treated with Lys-des[Arg9]bradykinin (LDBK) or bradykinin (BK) were used to evaluate migration and invasion. Des-[Arg9]-Leu8-BK and HOE-140 were used as antagonists for the B1 and B2 receptors. MDA-MB-231 cells incubated or not with antagonists were subcutaneously inoculated in BALBc NOD/SCID mice to evaluate tumor growth. LDBK and BK treatment significantly increased migration and invasion in breast cancer cells, effects that were negated when antagonists were used. The use of antagonists in vivo inhibited tumor growth. Moreover, the migration and invasion induced by kinins in breast cancer cells were inhibited when focal adhesion kinase (FAK) and Src inhibitors were used. The novelty revealed in our work is that B1 and B2 receptors activated by LDBK and BK induce migration and invasion in breast cancer cells via a mechanism that involves the FAK-Src signaling pathway, and the antagonism of both receptors in vivo impairs breast tumor growth.

A Computational Perspective into Binding Mechanism of a potent FAK Inhibitor as Anticancer Drug Candidate: Insights from Molecular Dynamics Simulations

Focal adhesion kinase (FAK) is an important non-receptor tyrosine kinase (nRTK) with crucial role in primary cell functions. Fundamental cellular processes, such as migration, adhesion, proliferation, and survival, are regulated by FAK. The tumorigenesis of FAK is very important since it is overexpressed in advanced cancers, causes malignant features and induces cancer metastasis. The available evidence proposes FAK as a promising target for cancer therapy. At the moment, there are no FAK inhibitors (FAKIs) in the market but several small molecule FAKIs have been developed and a few of them entered into clinical studies as anticancer agents. In spite of these achievements, development of selective and potent FAKIs may be partly hampered by the lack of crystallographic or structural data. This limitation could be resolved through proposing robust ligand–protein binding models to design new FAKIs. GSK2256098 is a small molecule ATP-competitive FAKI that undergoes clinical trials as a monotherapy or in combination with other medications against advanced solid tumors. GSK2256098 have been proven to be a selective and potent agent (IC[Formula: see text] 0.4 nM) with respect to other clinical candidates. With regard to appropriate characteristics, this molecule is particularly amenable for performing computational modeling studies. In this study, we try to propose an applicable binding model of GSK2256098 inside the FAK kinase domain. For this purpose, molecular docking, all-atom 200-ns molecular dynamics simulations and free-energy-calculation methods were applied as consecutive modeling techniques. Atomic insight and dynamic evolution of the system were used to attain a stable binding mode and infer chemical interactions of GSK2256098 inside the kinase domain of FAK. Although complementary investigations need to be conducted, obtained results may offer a structural basis for the development of potent and selective FAKIs.

Integrated analysis of bulk and single-cell RNA sequencing reveals the impact of nicotinamide and tryptophan metabolism on glioma prognosis and immunotherapy sensitivity

BackgroundNicotinamide and tryptophan metabolism play important roles in regulating tumor synthesis metabolism and signal transduction functions. However, their comprehensive impact on the prognosis and the tumor immune microenvironment of glioma is still unclear. The purpose of this study was to investigate the association of nicotinamide and tryptophan metabolism with prognosis and immune status of gliomas and to develop relevant models for predicting prognosis and sensitivity to immunotherapy in gliomas.MethodsBulk and single-cell transcriptome data from TCGA, CGGA and GSE159416 were obtained for this study. Gliomas were classified based on nicotinamide and tryptophan metabolism, and PPI network associated with differentially expressed genes was established. The core genes were identified and the risk model was established by machine learning techniques, including univariate Cox regression and LASSO regression. Then the risk model was validated with data from the CGGA. Finally, the effects of genes in the risk model on the biological behavior of gliomas were verified by in vitro experiments.ResultsThe high nicotinamide and tryptophan metabolism is associated with poor prognosis and high levels of immune cell infiltration in glioma. Seven of the core genes related to nicotinamide and tryptophan metabolism were used to construct a risk model, and the model has good predictive ability for prognosis, immune microenvironment, and response to immune checkpoint therapy of glioma. We also confirmed that high expression of TGFBI can lead to an increased level of migration, invasion, and EMT of glioma cells, and the aforementioned effect of TGFBI can be reduced by FAK inhibitor PF-573,228.ConclusionsOur study evaluated the effects of nicotinamide and tryptophan metabolism on the prognosis and tumor immune microenvironment of glioma, which can help predict the prognosis and sensitivity to immunotherapy of glioma.

Irisin promotes intestinal epithelial cell proliferation via Wnt/β-catenin and focal adhesion kinase signaling pathways

The regeneration of epithelia is crucial for maintaining intestinal homeostasis. Irisin is an exercise-induced hormone originally found to be secreted by skeletal muscles, thereby regulating energy metabolism. Recent studies have revealed that irisin protected against gut inflammation. However, the direct effects of irisin on the intestinal epithelial cells remain to be elucidated. In this study, mouse intestinal organoids were used to assess the effects of irisin on the proliferation of the intestinal epithelial cells. At a concentration of 100 ng/mL irisin significantly increased the growth of the intestinal organoids and upregulated the Wnt/β-catenin and focal adhesion kinase (FAK) signaling pathway genes. Notably, a FAK inhibitor 14 blocked the effects of irisin on the proliferation of the intestinal epithelial cells by inhibiting FAK phosphorylation, as well as the expressions of Wnt target genes. Furthermore, irisin (100 ng/mL) improved the recovery of the intestinal organoids from cellular damages caused by TNF-α, and markedly increased the expression of Wnt target genes in the intestinal epithelial cells. Taken together, irisin activates Wnt/β-catenin and FAK signaling pathways in the intestinal epithelial cells, thereby promoting intestinal epithelial self-renewal under normal homeostatic conditions and intestinal epithelial regeneration upon damages.

Focal Adhesion Kinase Inhibition Ameliorates Burn Injury-Induced Chronic Pain in Rats.

Burn injury-induced pain (BIP) is a significant global health concern, affecting diverse populations including children, military veterans, and accident victims. Current pharmacotherapeutics for the management of BIP are associated with severe side effects including drug addiction, respiratory depression, sedation, and constipation posing significant barrier to their clinical utility. In the present study, we have investigated the potential role of focal adhesion kinase (p-FAK) for the very first time in BIP and elucidated the associated underlying mechanisms. Defactinib (DFT), a potent p-FAK inhibitor, administered at doses of 5, 10, and 20mg/kg via intraperitoneal injection, demonstrates significant efficacy in reducing both evoked and spontaneous pain without causing addiction or other central nervous system toxicities. Burn injury triggers p-FAK-mediated phosphorylation of Erk1/2 and NR2B signaling in the DRG, resulting in heightened hypersensitivity through microglial activation, neuropeptide release, and elevated proinflammatory cytokines. Defactinib (DFT) counteracts these effects by reducing NR2B upregulation, lowering substance P levels, inhibiting microglial activation, and restoring IL-10 levels while leaving CGRP levels unchanged. These findings provide valuable insights into the pivotal role of p-FAK in regulating BIP and highlight the potential for developing novel therapeutics for burn injury-induced pain with minimal side effects.

MYO6 contributes to tumor progression and enzalutamide resistance in castration-resistant prostate cancer by activating the focal adhesion signaling pathway

BackgroundEnzalutamide (Enz) resistance is a poor prognostic factor for patients with castration-resistant prostate cancer (CRPC), which often involves aberrant expression of the androgen receptor (AR). Myosin VI (MYO6), one member of the myosin family, plays an important role in regulating cell survival and is highly expressed in prostate cancer (PCa). However, whether MYO6 is involved in Enz resistance in CRPC and its mechanism remain unclear.MethodsMultiple open-access databases were utilized to examine the relationship between MYO6 expression and PCa progression, and to screen differentially expressed genes (DEGs) and potential signaling pathways associated with the MYO6-regulated Enz resistance. Both in vitro and in vivo tumorigenesis assays were employed to examine the impact of MYO6 on the growth and Enz resistance of PCa cells. Human PCa tissues and related clinical biochemical data were utilized to identify the role of MYO6 in promoting PCa progression and Enz resistance. The molecular mechanisms underlying the regulation of gene expression, PCa progression, and Enz resistance in CRPC by MYO6 were investigated.ResultsMYO6 expression increases in patients with PCa and is positively correlated with AR expression in PCa cell lines and tissues. Overexpression of AR increases MYO6 expression to promote PCa cell proliferation, migration and invasion, and to inhibit PCa cell apoptosis; whereas knockdown of MYO6 expression reverses these outcomes and enhances Enz function in suppressing the proliferation of the Enz- sensitive and resistant PCa cells both in vitro and in vivo. Mechanistically, AR binds directly to the promoter region (residues − 503 to − 283 base pairs) of MYO6 gene and promotes its transcription. Furthermore, MYO6 activates focal adhesion kinase (FAK) phosphorylation at tyrosine-397 through integrin beta 8 (ITGB8) modulation to promote PCa progression and Enz resistance. Notably, inhibition of FAK activity by Y15, an inhibitor of FAK, can resensitize CRPC cells to Enz treatment in cell lines and mouse xenograft models.ConclusionsMYO6 has pro-tumor and Enz-resistant effects in CRPC, suggesting that targeting MYO6 may be beneficial for ENZ-resistant CRPC therapy through the AR/MYO6/FAK signaling pathway.

Stromal reprogramming overcomes resistance to RAS-MAPK inhibition to improve pancreas cancer responses to cytotoxic and immune therapy.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that is often resistant to therapy. An immune suppressive tumor microenvironment (TME) and oncogenic mutations in KRAS have both been implicated as drivers of resistance to therapy. Mitogen-activated protein kinase (MAPK) inhibition has not yet shown clinical efficacy, likely because of rapid acquisition of tumor-intrinsic resistance. However, the unique PDAC TME may also be a driver of resistance. We found that long-term focal adhesion kinase (FAK) inhibitor treatment led to hyperactivation of the RAS/MAPK pathway in PDAC cells in mouse models and tissues from patients with PDAC. Concomitant inhibition of both FAK (with VS-4718) and rapidly accelerated fibrosarcoma and MAPK kinase (RAF-MEK) (with avutometinib) induced tumor growth inhibition and increased survival across multiple PDAC mouse models. In the TME, cancer-associated fibroblasts (CAFs) impaired the down-regulation of MYC by RAF-MEK inhibition in PDAC cells, resulting in resistance. By contrast, FAK inhibition reprogramed CAFs to suppress the production of FGF1, which can drive resistance to RAF-MEK inhibition. The addition of chemotherapy to combined FAK and RAF-MEK inhibition led to tumor regression, a decrease in liver metastasis, and improved survival in KRAS-driven PDAC mouse models. Combination of FAK and RAF-MEK inhibition alone improved antitumor immunity and priming of T cell responses in response to chemotherapy. These findings provided the rationale for an ongoing clinical trial evaluating the efficacy of avutometinib and defactinib in combination with gemcitabine and nab-paclitaxel in patients with PDAC and may suggest further paths for combined stromal and tumor-targeting therapies.

Combined machine learning models, docking analysis, ADMET studies and molecular dynamics simulations for the design of novel FAK inhibitors against glioblastoma

Gliomas, particularly glioblastoma (GBM), are highly aggressive brain tumors with poor prognosis and high recurrence rates. This underscores the urgent need for novel therapeutic approaches. One promising target is Focal adhesion kinase (FAK), a key regulator of tumor progression currently in clinical trials for glioma treatment. Drug development, however, is both challenging and costly, necessitating efficient strategies. Computer-Aided Drug Design (CADD), especially when combined with machine learning (ML), streamlines the processes of virtual screening and optimization, significantly enhancing the efficiency and accuracy of drug discovery. Our study integrates ML, docking analysis, ADMET (absorption, distribution, metabolism, elimination, and toxicity) studies to identify novel FAK inhibitors specific to GBM. Predictive models showed strong performance, with an R2 of 0.892, MAE of 0.331, and RMSE of 0.467 using protein-level IC50 data in combined CDK, CDK extended fingerprints, and substructure fingerprint counts derived from 1280 FAK inhibitors. Another model, based on IC50 data from 2608 compounds tested on U87-MG cells, achieved an R2 of 0.789, MAE of 0.395, and RMSE of 0.536. Using these models, we efficiently identified 275 potentially active compounds out of 5107 candidates. Subsequent ADMET analysis narrowed this down to 16 potential FAK inhibitors that meet the established drug-likeness criteria. Moreover, molecular dynamics (MD) simulations validated the stable binding interactions between the selected compounds and the FAK protein. This study highlights the effectiveness of combining ML, docking analysis, and ADMET studies to rapidly identify potential FAK inhibitors from large databases, providing valuable insights for the systematic design of FAK inhibitors.

BRAF Modulates the Interplay Between Cell-Cell and Cell-Extracellular Matrix Adhesions in PECAM-1-Mediated Mechanotransduction.

Mechanotransduction, the process of how cells sense and convert mechanical stimuli into biochemical response, is crucial in the migration of leukocytes or cancer cells through the endothelium during inflammation or metastasis. Migrating cells exert forces on the endothelium through cell surface adhesion molecules, such as platelet endothelial adhesion molecule PECAM-1, and this is essential for a successful transmigration. To study PECAM-1-mediated mechanotransduction, we applied PECAM-1-antibody-coated magnetic beads and exerted about 40 pN force on the endothelial monolayer. We show that force increases cell-ECM adhesion in the cell center and is accompanied by the opening of cell-cell junctions. Upon depletion of the MEK/ERK kinase, BRAF force increases cell-ECM adhesion both at the cell periphery and in the cell center, but this does not result in the opening of cell-cell junctions. Decreasing cell-ECM adhesion in BRAF-depleted cells through FAK inhibition results in the remodeling of cell-cell junctions. Force-induced increase in cell-ECM adhesion in the cell center correlates with the activation of the transcriptional cofactor Yes-associated protein (YAP). Furthermore, the induced activation of YAP through LATS inhibition prevents junctional remodeling in control cells. Thus, the activation of YAP might determine the strength of cell-cell junctions during PECAM-1-mediated mechanotransduction.

FAK inhibition delays liver repair after acetaminophen-induced acute liver injury by suppressing hepatocyte proliferation and macrophage recruitment

FAK inhibition delays liver repair after acetaminophen-induced acute liver injury by suppressing hepatocyte proliferation and macrophage recruitment

Focal Adhesion Kinase (FAK) inhibition induces membrane accumulation of aquaporin2 (AQP2) through endocytosis inhibition and actin depolymerization in renal epithelial cells.

Cellular trafficking of the water channel aquaporin 2 (AQP2) is regulated by the actin cytoskeleton in collecting duct principal cells (PC) to maintain proper water balance in animals. Critical actin depolymerization/polymerization events are involved in both constitutive AQP2 recycling, and the pathway stimulated by vasopressin receptor signaling. Focal adhesion kinase (FAK) plays an important role in modulating the actin cytoskeleton through inhibiting small GTPases, and multiple studies have shown the involvement of FAK in insulin and cholesterol trafficking through actin regulation. To understand whether FAK contributes to water reabsorption by the kidney, we performed a series of in vitro experiments to examine the involvement of FAK and its signaling in mediating AQP2 trafficking in cultured renal epithelial cells. Our data showed that FAK inhibition by specific inhibitors caused membrane accumulation of AQP2 in AQP2expressing LLCPK1 cells by immunofluorescence staining. AQP2 membrane accumulation induced by FAK inhibition is associated with significantly reduced endocytosis of AQP2 via the clathrin-mediated endocytosis pathway. Moreover, AQP2 membrane accumulation induced by FAK inhibition also occurred in cells expressing the constitutive dephosphorylation mutant of AQP2, S256A. This was confirmed by immunoblotting using a specific antibody against phospho-serine 256 AQP2, supporting a phosphorylation independent mechanism. Finally, we demonstrated that inhibition of FAK caused reduced RhoA signaling and promoted F-actin depolymerization. In conclusion, our study identifies FAK signaling as a pathway that could provide a novel therapeutical avenue for AQP2 trafficking regulation in water balance disorders.

Mechanism of collagen type IV regulation by focal adhesion kinase during retained fetal membranes in dairy cows

Retained fetal membranes (RFM) is an important reproductive disease in dairy cows, caused by maternal and fetal placental tissue adhesion. The main collagen in maternal and fetal placenta tissues is collagen type IV (COL-IV) and its breakdown is the key to placental expulsion. Focal adhesion kinase (FAK) has been shown to regulate the hydrolysis of Col-IV by affecting the activity of MMP-2 and MMP-9 activity, but the regulation of the mechanisms involved in placenta expulsion in dairy cows after postpartum are still unclear. The aim of this study was to investigate the pathogenic mechanism of RFM by studying the relationship between the FAK signaling pathway and COL-IV regulation. Maternal placental tissues were collected from six healthy and six cows with RFM of similar age, parity, body condition and milk yield at 12 h postpartum. In vitro experiments were performed on bovine endometrial epithelial cells from three groups including a FAK inhibitor group, a FAK activator group and a control group without FAK inhibitor and activator. The abundance of molecules involved in the FAK signaling pathway and COL-IV was detected by immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The immunohistochemical results showed that the key molecules of FAK signaling pathway FAK, Src, MMP-2 and MMP-9 and Col-IV were expressed in placental tissues. The expression level of FAK, Src, MMP-2, and MMP-9 were significantly down-regulated (P < 0.05) and the abundances of COL-IV were significantly up-regulated (P < 0.05) in maternal placental tissues of RFM cows compared with healthy cows. In the FAK inhibitor treatment group, the relative expression levels of FAK and other related proteins were significantly down-regulated (P < 0.05) and the relative expression levels of COL-IV were significantly up-regulated (P < 0.05) with the results of the FAK activation group the opposite. These results indicated that FAK in maternal endometrial epithelial cells could regulate the hydrolysis process of Col-IV through the expression of key factors of signaling pathways and promote collagen hydrolysis, which in turn facilitated the process of postpartum placenta expulsion in dairy cows.

Assessment of the in vitro metabolic stability of CEP-37440, a selective FAK/ALK inhibitor, in HLMs using fast UPLC-MS/MS method: in silico metabolic lability and DEREK alerts screening.

CEP-37440 was synthesized and supplied by the research and development division of Teva Branded Pharmaceutical Products (West Chester, PA, United States). CEP-37440 represents a newly developed compound that exhibits selectivity inhibition of Focal Adhesion Kinase and Anaplastic Lymphoma Kinase FAK/ALK receptors, demonstrating novel characteristics as an orally active inhibitor. The simultaneous inhibition of ALK and FAK can effectively address resistance and enhance the therapeutic efficacy against tumors through a synergistic mechanism. The objective of this research was to create an LC-MS/MS method that is precise, efficient, environmentally friendly, and possesses a high level of sensitivity for the quantification of CEP-37440 in human liver microsomes (HLMs). The aforementioned approach was subsequently employed to evaluate the metabolic stability of CEP-37440 in HLMs in an in vitro setting. The validation procedures for the LC-MS/MS analytical method in the HLMs were performed following the bio-analytical method validation guidelines set out by the US-FDA. The AGREE program was utilized to assess the ecological impacts of the current LC-MS/MS methodology. The calibration curve linearity was seen in the range of 1-3000ng/mL. The inter-day accuracy (% RE) exhibited a range of -2.33% to 3.22%, whilst the intra-day accuracy demonstrated a range of -4.33% to 1.39%. The inter-day precision (% RSD) exhibited a range of 0.38% to 3.60%, whilst the intra-day precision demonstrated a range of 0.16% to 6.28%. The determination of the in vitro half-life (t1/2) and moderate intrinsic clearance (Clint) of CEP-37440 yielded values of 23.24min and 34.74mL/min/kg, respectively. The current manuscript is considered the first analytical study for CEP-37440 quantification with the application to metabolic stability assessment. These results suggest that CEP-37440 can be categorized as a pharmaceutical agent with a moderate extraction ratio. Consequently, it is postulated that the administration of CEP-37440 to patients may not lead to the accrual of dosages within the human organs. According to in silico P450 metabolic and DEREK software, minor structural alterations to the ethanolamine moiety or substitution of the group in drug design have the potential to enhance the metabolic stability and safety profile of novel derivatives in comparison to CEP-37440.