Inhibition Of Focal Adhesion Kinase Phosphorylation Research Articles

Schisandrin B prevents ulcerative colitis and colitis-associated-cancer by activating focal adhesion kinase and influence on gut microbiota in an in vivo and in vitro model

Colitis-associated cancer (CAC) has a close relationship with ulcerative colitis (UC). Therapeutic effect of Schisandrin B (SchB) on UC and CAC remains largely unknown. We investigated the preventative effect of SchB on the dextran sulphate sodium (DSS) model of UC and azoxymethane (AOM)/DSS model of CAC. Furthermore, focal adhesion kinase (FAK) activation and influence on commensal microbiota are important for UC treatment. Impact on FAK activation by SchB in UC development was evaluated in vivo and vitro. We also conducted 16S rRNA sequencing to detect regulation of gut microbiota by SchB. Enhanced protection of intestinal epithelial barrier by SchB through activating FAK contributed to protective effect on colon for the fact that protection of SchB can be reversed by inhibition of FAK phosphorylation. Furthermore, influence on gut microbiota by SchB also played a significant role in UC prevention. Our results revealed that SchB was potent to prevent UC by enhancing protection of intestinal epithelial barrier and influence on gut microbiota, which led to inhibition of CAC. SchB was potential to become a new treatment for UC and prevention of CAC.

Daurinol blocks breast and lung cancer metastasis and development by inhibition of focal adhesion kinase (FAK)

FAK overexpression has been reported in diverse primary and metastatic tumor tissues, supporting its pro-tumorigenic and pro-metastatic roles. Therefore, we have developed a neo-treatment strategy using daurinol to effectively treat cancer metastasis. Daurinol blocked cancer cell migration and invasion in vitro and exhibited anti-metastatic activity in an experimental metastasis model of breast and lung cancer. Daurinol selectively inhibited phosphorylation of FAK at Tyr925, Tyr576/577, and Tyr397 sites in a dose- and time-dependent manner. Daurinol effectively suppressed migration and invasion of MDA-MB-231 and A549 cancer cells. These data were associated with inhibition of expression and secretion of invasion factors, including matrix metalloproteinase (MMP) 2, MMP9, and urokinase plasminogen activator (uPA). Consistent with these in vitro results, daurinol (10 mg/kg; Oral gavage) effectively inhibited breast and lung cancer metastasis in a mouse model. In addition, daurinol showed strong suppressive activity of cell survival as revealed by colony formation assays. Analysis of cellular phenotypes revealed that inhibition of FAK phosphorylation in cancer cells limited colony formation, cell migration, and invasion, thereby reducing the cell proliferation rate. Furthermore, daurinol significantly reduced tumor development in 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK)/benzo(a)pyrene (BaP)-treated A/J mice. Our results suggest that daurinol suppresses lung metastasis through inhibition of migration and survival via blockade of FAK activity.

Abstract A23: Daurinol suppresses human cancer metastasis by inhibition of focal adhesion kinase (FAK) signaling pathways

Abstract Background and Purpose: Globally most of the cancers associated with mortality and morbidity arise from metastatic spread of primary tumors. Traditional anti-cancer drugs mostly focus on inhibiting tumor cell growth or killing tumor cells directly or indirectly; however, there are only a few drugs that specifically inhibit metastasis of tumor cells. Noteworthy, the focal adhesive kinase (FAK) plays an important role in cytoskeleton remodeling and in regulating the tumor cell invasiveness and metastasis. The FAK is a tyrosine kinase that is localized to cellular focal adhesions and is associated with a number of other proteins, such as the integrin adhesion receptors clusters called focal adhesions. FAK overexpression has been detected in diverse primary and metastatic tumor tissues, supporting its pro-tumorigenic and pro-metastatic roles. Daurinol, which is a natural compound purified from Haplophyllum dauricum, has historically been used to treat tumors. Anti-proliferative activities of daurinol against various human cancer cells have been reported and daurinol displayed strong anti-tumor activity without any significant adverse effects. Therefore, we have developed a neo-treatment strategy with daurinol to effectively treat cancer. Herein, we extend our knowledge with the characterization of daurinol, an inhibitor of metastasis which blocks FAK signaling in breast and lung cancer. Results: Daurinol blocked cancer cell migration and invasion in in vitro and exhibited anti-metastatic activity in orthotopic breast cancer and xenograft lung cancer mouse models. Daurinol (10 mg/kg; Oral gavage) inhibited effectively breast and lung metastasis. Consistently with these in vivo results, a relatively low concentration of daurinol suppressed cell migration and Invasion in MDA-MB-231 and A549 human cancer cells. These data were associated with inhibition of invasion factors, such as matrix metalloproteinase (MMP)-2, MMP-9, and urokinase plasminogen activator (uPA) secretion. Daurinol also significantly decreased the tumor development in 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) / benzo(a)pyrene (BaP)-treated A/J mice. Daurinol showed strong growth suppressive activity as revealed by colony formation assays. In addition, daurinol selectively inhibited the phosphorylation of FAK at Tyr925, Tyr 576/577, and Tyr 397 sites in a dose- and time-dependent manner. Analysis of cellular phenotypes revealed that the inhibition of FAK phosphorylation in cancer cells limits their colony-formation, cell migration and invasion less affecting cell proliferation rate. These data suggest that the effects of daurinol on metastasis and tumor development in cancer cells are restricted in cellular survival machinery. Conclusion: Our results suggest that daurinol suppresses lung metastasis through inhibition of migration and survival via blockade of FAK activity. However, it still remains to be seen whether daurinol has direct anticancer actions in clinics. Citation Format: Jong Kyu Woo, Ji-Youn Park, Chu Won Nho, Seung Hyun Oh. Daurinol suppresses human cancer metastasis by inhibition of focal adhesion kinase (FAK) signaling pathways. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A23.

Tyrosine 397 phosphorylation is critical for FAK-promoted Rac1 activation and invasive properties in oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) is a common cancer worldwide. Despite advances in diagnosis and therapy, treatment options for patients with metastatic OSCC are few, due in part to the limited understanding of the molecular events involved in the invasion and metastasis of OSCC. In this study, we investigated the expression of focal adhesion kinase (FAK) and its tyrosine 397 phosphorylation (pY397) in the tissue specimens of OSCC. The roles of pY397 in regulating the activities of Rac1 and cortactin and the invasive properties of OSCC cells were further determined. Results from immunohistochemical analyses in 9 benign, 19 premalignant, and 19 malignant oral tissues showed that the immunoreactivity of FAK was observed in 5 benign (56%), 19 premalignant (100%), and 18 malignant tissues (95%), whereas the immunoreactivity of pY397 was only found in 1 of 9 (11%) benign lesions but was observed in 9 premalignant (47%) and 12 malignant (63%) lesions. Compared with the low-invading SCC4 cells, the high-invading OECM-1 cells exhibited higher levels of FAK expression and pY397, correlating with higher levels of GTP-bound Rac1 and cortactin phosphorylation. Manipulation of FAK expression or Y397 phosphorylation in SCC4, FaDu, OECM-1, or HSC-3 cells regulated their Rac1 activities and invasive properties. Furthermore, treatment of NSC23766, a Rac1-specific inhibitor, in OECM-1 and HSC-3 cells led to reduced invasive properties. Nevertheless, knockdown of FAK expression or suppression of pY397 had no effect on the cortactin activity in OECM-1 cells. The data collectively suggest that pY397 plays critical roles in the FAK-promoted Rac1 activation and invasive properties in OSCC cells. Thus, the inhibition of FAK phosphorylation at Y397 or Rac1 activity can serve as a therapeutic strategy for treating patients with metastatic OSCC.

DNA copy number aberrations in small-cell lung cancer reveal activation of the focal adhesion pathway

Small-cell lung cancer (SCLC) is the most aggressive subtype of lung cancer in its clinical behavior, with a 5-year overall survival as low as 5%. Despite years of research in the field, molecular determinants of SCLC behavior are still poorly understood, and this deficiency has translated into an absence of specific diagnostics and targeted therapeutics. We hypothesized that tumor DNA copy number alterations would allow the identification of molecular pathways involved in SCLC progression. Array comparative genomic hybridization was performed on DNA extracted from 46 formalin-fixed paraffin-embedded SCLC tissue specimens. Genomic profiling of tumor and sex-matched control DNA allowed the identification of 70 regions of copy number gain and 55 regions of copy number loss. Using molecular pathway analysis, we found a strong enrichment in these regions of copy number alterations for 11 genes associated with the focal adhesion pathway. We verified these findings at the genomic, gene expression and protein level. Focal Adhesion Kinase (FAK), one of the central genes represented in this pathway, was commonly expressed in SCLC tumors and constitutively phosphorylated in SCLC cell lines. Those were poorly adherent to most substrates but not to laminin-322. Inhibition of FAK phosphorylation at Tyr(397) by a small-molecule inhibitor, PF-573,228, induced a dose-dependent decrease of adhesion and an increase of spreading in SCLC cell lines on laminin-322. Cells that tended to spread also showed a decrease in focal adhesions, as demonstrated by a decreased vinculin expression. These results support the concept that pathway analysis of genes in regions of copy number alterations may uncover molecular mechanisms of disease progression and demonstrate a new role of FAK and associated adhesion pathways in SCLC. Further investigations of FAK at the functional level may lead to a better understanding of SCLC progression and may have therapeutic implications.

Ciprofloxacin-mediated inhibition of tenocyte migration and down-regulation of focal adhesion kinase phosphorylation

Ciprofloxacin-induced tendinopathy and tendon rupture have been previously described, principally affecting the Achilles tendon. However, the underlying mechanism remains unclear. Tendon healing requires migration of tenocytes to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of ciprofloxacin on migration of tenocytes intrinsic to rat Achilles tendon. Whether a correlation exits between this effect and the expression and phosphorylation of focal adhesion kinase (FAK), which is a positive regulator of cell motility, was also investigated. Using cultured tenocytes, migration was evaluated by counting the number of initial cell outgrowth from the tendon explants and by transwell filter migration assay. Tenocyte spreading was also evaluated microscopically. The serum-induced protein expression and phosphorylation of FAK were determined by Western blot analysis in synchronized tenocytes. Ciprofloxacin dose-dependently inhibited tenocytes outgrowth from the explants ex vivo, migration of tenocytes through the transwell filter, as well as cell spreading in vitro. Suppression of FAK phosphorylation was revealed by Western blot analyses. In conclusion, ciprofloxacin inhibits tenocyte migration in a process that is probably mediated by inhibition of FAK phosphorylation.

Critical role of estrogen receptor on anoikis and invasion of squamous cell carcinoma

Estrogen receptor (ER) plays an important role in various physiological functions. We examined whether ERalpha and ERbeta are expressed in squamous cell carcinoma (SCC), and whether ER is a potential target for antitumor therapy. High-level expression of ERbeta, but not ERalpha, was observed in tumor cells of human primary SCC tissues and various SCC cultured cell lines. Treatment with ER antagonist (tamoxifen), but not agonist (estradiol), caused apoptotic cell death of SCC cells in a concentration- and time-dependent manner. Adhesion of SCC was inhibited by the treatment with tamoxifen, but not with estradiol. Tamoxifen reduced the phosphorylation of focal adhesion kinase (FAK), resulting in decreases in phosphorylation of extracellular signal-related kinase (Erk) and mitogen-activated protein kinase. Inhibition of FAK phosphorylation is accompanied by disorder of the cytoskeletal component actin. The cell death caused by tamoxifen is therefore the result of direct interference in cell adhesion, which is called 'anoikis', involving a decrease in intracellular FAK signaling. Expression of epidermal growth factor receptor was also inhibited by treatment with a high concentration of tamoxifen. Knockdown of ERbeta by small interfering RNA inhibited the proliferation of SCC. In addition, tamoxifen strongly inhibited invasion of SCC. These results imply a potentially important role for ER, whose inhibition may be effective for the treatment of SCC and the prevention of invasion and metastasis.

Anti-cancer activity of NVP-TAE226, a potent dual FAK/IGF-IR kinase inhibitor, against pancreatic carcinoma

13162 Background: Focal adhesion kinase (FAK) is a non-receptor cytoplasmic tyrosine kinase that regulates multiple cell functions. Elevated expression levels of FAK have been detected in various tumor samples and are closely correlated with invasive potential. Activation of integrins and the growth factor receptors result in FAK autophosphorylation at Y397 and the presentation of suitable binding sites for proteins containing either SH2 or phosphotyrosine binding domains. Recent evidences suggest that FAK plays important roles in cancer cell proliferation and survival. IGF-IR function is required for tumor cell survival, but dispensable for survival of normal cells. Therefore, a dual inhibitor of both kinases may selectively block the growth, migration, and survival of FAK- and IGF-IR- expressing tumor cells compared to proliferating and migrating normal cells. Methods: In this study, anti-cancer activity of NVP-TAE226 that is identified as a potent and selective FAK inhibitor was evaluated in cancer cell lines panel and MIA PaCa-2 pancreatic carcinoma in vivo model. Results: Mean GI50 value of NVP-TAE226 against 37 cancer cell lines was 0.76 μmole/L. Inhibition of cancer cell proliferation was not affected by expression of P-glycoprotein, suggesting that NVP-TAE226 is not served as a substrate of P-glycoprotein. Oral administration of NVP-TAE226 efficiently inhibited MIA PaCa-2 human pancreatic tumor growth at all doses tested. Tumor stasis was observed at a dose of 30 mg/kg, qd for 7×/week and tumor regression was observed at a dose of 100 mg/kg, qd for 5×/week. All animals tolerated NVP-TAE226 treatment up to 100 mg/kg, 5×/wk, qd, po for 2 weeks with no body weight loss. Inhibition of downstream signaling such as phosphorylation of Akt at Serine473 was accompanied by inhibition of FAK phosphorylation in human pancreatic carcinoma cell lines. Conclusions: NVP-TAE226 is a novel class of selective and small molecule kinase inhibitors with a potent in vivo activity and potential therapeutic application. No significant financial relationships to disclose.

Activation of focal adhesion kinase enhances the adhesion and invasion of pancreatic cancer cells via extracellular signal-regulated kinase-1/2 signaling pathway activation

BackgroundInteraction with integrin and focal adhesion kinase (FAK) regulates the cancer cell adhesion and invasion into extracellular matrix (ECM). In addition, phosphorylation of FAK correlates with the increase of cell motility and invasion. Adhesion and spreading of cancer cells on a variety of ECM proteins, including collagen type IV (Coll IV), leads to an increase in tyrosine phosphorylation and activation of FAK. In this study, we investigated the mechanism of activation of FAK and its downstream extracellular signal-regulated kinase (ERK)-1/2 signaling following stimulation by interleukin (IL)-1α and adhesion to ECM with subsequent enhancement of pancreatic cancer cell adhesion and invasion.ResultsIn immunoblotting analysis, all three pancreatic cancer cell lines (AsPC-1, BxPC-3, and Capan-2) expressed the protein of FAK and β1 integrin. Enhancement of FAK protein association with β1 integrin when cells were plated on Coll IV was more increased by stimulation with IL-1α. Preincubation with anti-β1 integrin antibody and FAK siRNA transfection inhibited the association of FAK with β1 integrin of pancreatic cancer cells. FAK phosphorylation was observed by adhesion to Coll IV, furthermore, stronger FAK phosphorylation was observed by stimulation with IL-1α of pancreatic cancer cells adhered to Coll IV in time-dependent manner. Genistein, a tyrosine kinase inhibitor, markedly inhibited the FAK phosphorylation. IL-1α stimulation and Coll IV adhesion enhanced the activation of Ras, as evidenced by the increased Ras-GTP levels in pancreatic cancer cells. Activation of Ras correlated with the phosphorylation of ERK. While not statistical affecting the apoptosis of pancreatic cancer cells, IL-1α-induced adhesion and invasion on Coll IV were inhibited with FAK gene silencing by siRNA, β1 integrin blocking, and inhibition of FAK phosphorylation. PD98059, a MEK inhibitor, also inhibited IL-1α-induced enhancement of adhesion and invasion in pancreatic cancer cells.Conclusion Our results demonstrated that activation of FAK is involved with the aggressive capability in pancreatic cancer through Ras/ERK signaling pathway. Based on our results, we suggest that the modification of IL-1, FAK, and integrins functions might be a novel therapeutic approach to aggressive spread of pancreatic cancer.

Regulation of focal adhesion kinase by its amino-terminal domain through an autoinhibitory interaction.

We have investigated a role for the amino-terminal FERM-like domain of the focal adhesion kinase (FAK) as a negative regulator of its own activity and phosphorylation state. Deletion of the first 375 amino acids from the amino terminus of FAK increases its catalytic activity in vitro, its phosphorylation when expressed in mammalian cells, and the phosphorylation of a FAK substrate, paxillin. Deletion mutants are phosphorylated in suspension, suggesting that they are no longer regulated by adhesion. The amino terminus of FAK can interact with the kinase domain of FAK in vitro and in vivo, suggesting that it might act as an autoinhibitor of FAK activity. The amino terminus of FAK can act in trans to inhibit FAK phosphorylation when expressed in mammalian cells or to directly inhibit FAK activity in vitro. Expression of the amino terminus of FAK inhibits cell cycle progression in CHO cells, consistent with its inhibition of FAK phosphorylation and function in trans. A glutathione S-transferase fusion protein containing the cytoplasmic tail of the beta1 integrin stimulates FAK activity in vitro, suggesting that FAK could be regulated by molecular interactions with the amino terminus. Based on these and previous data, we propose a working model for activation of FAK in cell adhesion.

The C-terminal domain of focal adhesion kinase reduces the tumor cell invasiveness in chondrosarcoma cell lines

Human chondrosarcoma is a malignancy that has no effective systemic therapy, making the interruption of the metastatic cascade critical to enhance patient survival. The processes of local invasion and metastases share similar mechanisms at a cellular level. Focal adhesion kinase (FAK) has been implicated in local invasion of malignant tumor cells. In the current manuscript we examine the effect of FAK inhibition on cell attachment to extracellular matrix (ECM) and in vitro invasion. Bovine articular chondrocytes and two human chondrosarcoma cell lines were utilized to examine FAK activity in tumor cell invasiveness. Endogenous FAK activity was inhibited by adenoviral transfection with the C-terminal domain of FAK. This inhibition resulted from decreased FAK phosphorylation, while FAK expression remained unchanged. Inhibition of FAK phosphorylation and hence its activity lead to decreased cell adhesion to Type II collagen and decreased cell invasiveness. These effects were not due to changes in integrin expression, indicating that the inhibition was the result of disruption of outside: in signaling. There are three important aspects to these results. The first is that interruption of transmembrane signaling can affect cell attachment. The second is that in chondrosarcoma, cell differentiation correlates with FAK expression and metastatic potential. Thirdly, that cell invasiveness correlates with FAK activity and implies a mechanistic role for this molecular complex in local invasion and metastasis.

Human herpesvirus 8 envelope glycoprotein B mediates cell adhesion via its RGD sequence.

Human herpesvirus 8 (HHV-8) or Kaposi's sarcoma-associated herpesvirus, implicated in the pathogenesis of Kaposi's sarcoma, utilizes heparan sulfate-like molecules to bind the target cells via its envelope-associated glycoproteins gB and gpK8.1A. HHV-8-gB possesses the Arg-Gly-Asp (RGD) motif, the minimal peptide region of many proteins known to interact with subsets of host cell surface integrins. HHV-8 utilizes alpha3beta1 integrin as one of the receptors for its entry into the target cells via its gB interaction and induces the activation of focal adhesion kinase (FAK) (S. M. Akula, N. P. Pramod, F.-Z. Wang, and B. Chandran, Cell 108:407-419, 2002). Since FAK activation is the first step in the outside-in signaling necessary for integrin-mediated cytoskeletal rearrangements, cell adhesions, motility, and proliferation, the ability of HHV-8-gB to mediate the target cell adhesion was examined. A truncated form of gB without the transmembrane and carboxyl domains (gBdeltaTM) and a gBdeltaTM mutant (gBdeltaTM-RGA) with a single amino acid mutation (RGD to RGA) were expressed in a baculovirus system and purified. Radiolabeled HHV-8-gBdeltaTM, gBdeltaTM-RGA, and deltaTMgpK8.1A proteins bound to the human foreskin fibroblasts (HFFs), human dermal microvascular endothelial (HMVEC-d) cells, human B (BJAB) cells, and Chinese hamster ovary (CHO-K1) cells with equal efficiency, which was blocked by preincubation of proteins with soluble heparin. Maxisorp plate-bound gBdeltaTM protein induced the adhesion of HFFs and HMVEC-d and monkey kidney epithelial (CV-1) cells in a dose-dependent manner. In contrast, the gBdeltaTM-RGA and DeltaTMgpK8.1A proteins did not mediate adhesion. Adhesion mediated by gBdeltaTM was blocked by the preincubation of target cells with RGD-containing peptides or by the preincubation of plate-bound gBdeltaTM protein with rabbit antibodies against gB peptide containing the RGD sequence. In contrast, adhesion was not blocked by the preincubation of plate-bound gBdeltaTM protein with heparin, suggesting that the adhesion is mediated by the RGD amino acids of gB, which is independent of the heparin-binding domain of gB. Integrin-ligand interaction is dependent on divalent cations. Adhesion induced by the gBdeltaTM was blocked by EDTA, thus suggesting the role of integrins in the observed adhesions. Focal adhesion components such as FAK and paxillin were activated by the binding of gBdeltaTM protein to the target cells but not by gBdeltaTM-RGA protein binding. Inhibition of FAK phosphorylation by genistein blocked gBdeltaTM-induced FAK activation and cell adhesion. These findings suggest that HHV-8-gB could mediate cell adhesion via its RGD motif interaction with the cell surface integrin molecules and indicate the induction of cellular signaling pathways, which may play roles in the infection of target cells and in Kaposi's sarcoma pathogenesis.

GFP-FRNK disrupts focal adhesions and induces anoikis in neonatal rat ventricular myocytes.

Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase involved in adhesion-dependent signal transduction. FAK is highly expressed in cultured neonatal rat ventricular myocytes (NRVMs) and undergoes tyrosine autophosphorylation in response to cell adhesion, stretch, and growth factor stimulation. We previously showed that inhibition of FAK phosphorylation by adenovirally mediated overexpression of FRNK (the autonomously expressed C-terminal domain of FAK) prevented endothelin-1 (ET)-induced NRVM hypertrophy. One question raised by these studies was whether FRNK localized to focal adhesions and displaced FAK from sites required for downstream signaling. Therefore, we constructed a replication-defective adenovirus encoding a GFP-FRNK fusion protein (Adv-GFP-FRNK) and examined its effects on NRVM cytoarchitecture and signaling. Uninfected NRVMs contained small amounts of endogenous FRNK. NRVMs infected with Adv-GFP-FRNK expressed much larger amounts of a 66-/68-kDa protein that localized to costameres and focal adhesions. GFP-FRNK overexpression suppressed basal and ET-induced FAK phosphorylation and also inhibited ET-induced phosphorylation of PYK2, the other member of the FAK family of nonreceptor protein tyrosine kinases. In contrast, GFP-FRNK overexpression did not prevent ET-induced ERK, JNK, or p70S6K phosphorylation. Furthermore, GFP-FRNK resulted in the loss of detectable FAK and paxillin in focal adhesions, which was accompanied by reduced levels of total paxillin and, ultimately, cell detachment and apoptosis. We conclude that FRNK functions as a dominant-negative inhibitor of adhesion-dependent signaling by displacing FAK from focal adhesions and interfering with the anchorage of NRVMs that is necessary for cell survival, a process known as anoikis.