Focal adhesion kinase inhibitors are potent anti-angiogenic agents

A molecular landscape of quiescence and proliferation highlights the role of Pten in mammary gland acinogenesis

Cell context is key for cell state. Using physiologically relevant models of laminin-rich extracellular matrix (lrECM) induction of mammary epithelial cell quiescence and differentiation, we provide a landscape of the key molecules for the proliferation-quiescence decision, identifying multiple layers of regulation at the mRNA and protein levels. Quiescence occurred despite activity of Fak (also known as PTK2), Src and phosphoinositide 3-kinases (PI3Ks), suggesting the existence of a disconnecting node between upstream and downstream proliferative signalling. Pten, a lipid and protein phosphatase, fulfils this role, because its inhibition increased proliferation and restored signalling via the Akt, mTORC1, mTORC2 and mitogen-activated protein kinase (MAPK) pathways. Pten and laminin levels were positively correlated in developing murine mammary epithelia, and Pten localized apicolaterally in luminal cells in ducts and near the nascent lumen in terminal end buds. Consistently, in three-dimensional acinogenesis models, Pten was required for triggering and sustaining quiescence, polarity and architecture. The multilayered regulatory circuitry that we uncovered provides an explanation for the robustness of quiescence within a growth-suppressive microenvironment, which could nonetheless be disrupted by perturbations in master regulators such as Pten.

Activation of skeletal muscle FAPs by LPA requires the Hippo signaling via the FAK pathway

Lysophosphatidic acid (LPA) is a lysophospholipid that signals through six G-protein coupled receptors (LPARs), LPA₁ to LPA₆. LPA has been described as a potent modulator of fibrosis in different pathologies. In skeletal muscle, LPA increases fibrosis-related proteins and the number of fibro/adipogenic progenitors (FAPs). FAPs are the primary source of ECM-secreting myofibroblasts in acute and chronic damage. However, the effect of LPA on FAPs activation in vitro has not been explored. This study aimed to investigate FAPs' response to LPA and the downstream signaling mediators involved. Here, we demonstrated that LPA mediates FAPs activation by increasing their proliferation, expression of myofibroblasts markers, and upregulation of fibrosis-related proteins. Pretreatment with the LPA₁/LPA₃ antagonist Ki16425 or genetic deletion of LPA₁ attenuated the LPA-induced FAPs activation, resulting in decreased expression of cyclin e1, α-SMA, and fibronectin. We also evaluated the activation of the focal adhesion kinase (FAK) in response to LPA. Our results showed that LPA induces FAK phosphorylation in FAPs. Treatment with the P-FAK inhibitor PF-228 partially prevented the induction of cell responses involved in FAPs activation, suggesting that this pathway mediates LPA signaling. FAK activation controls downstream cell signaling within the cytoplasm, such as the Hippo pathway. LPA induced the dephosphorylation of the transcriptional coactivator YAP (Yes-associated protein) and promoted direct expression of target pathway genes such as Ctgf/Ccn2 and Ccn1. The blockage of YAP transcriptional activity with Super-TDU further confirmed the role of YAP in LPA-induced FAPs activation. Finally, we demonstrated that FAK is required for LPA-dependent YAP dephosphorylation and the induction of Hippo pathway target genes. In conclusion, LPA signals through LPA₁ to regulate FAPs activation by activating FAK to control the Hippo pathway.

Design, synthesis and evaluation of nitric oxide releasing derivatives of 2,4-diaminopyrimidine as novel FAK inhibitors for intervention of metastatic triple-negative breast cancer

To search for novel medicines for intervention of triple-negative breast cancer (TNBC), a series of phenylsulfonyl furoxan-based 2,4-diaminopyrimidine derivatives (8a-t) were designed and synthesized based on blocking FAK-mediated signaling pathways through both kinase-dependent and -independent manners. The most active compound 8f not only significantly inhibited FAK kinase activity (IC₅₀ = 27.44 nM), displayed potent inhibitory effects on the proliferation (IC₅₀ = 0.126 μM), invasion and migration of MDA-MB-231 cells, superior to the most widely studied FAK inhibitor, TAE226, bearing 2,4-diaminopyrimidine, but also released high levels of NO, contributing to blockage of FAK mediated-signaling pathways by upregulating of p53 as well as suppressing the Y397 phosphorylation and its downstream effectors, including p-Akt, MMP-2, and MMP-9 via kinase-independent manner, leading to apoptosis induction and decrease of FAs and SFs in TNBC cells. Importantly, 8f inhibited the lung metastasis of TNBC in vivo. Together, 8f may serve as a promising candidate for the treatment of metastatic TNBC.

Lack of Paxillin phosphorylation promotes single-cell migration in vivo

Focal adhesions are structures that physically link the cell to the extracellular matrix for cell migration. Although cell culture studies have provided a wealth of information regarding focal adhesion biology, it is critical to understand how focal adhesions are dynamically regulated in their native environment. We developed a zebrafish system to visualize focal adhesion structures during single-cell migration in vivo. We find that a key site of phosphoregulation (Y118) on Paxillin exhibits reduced phosphorylation in migrating cells in vivo compared to in vitro. Furthermore, expression of a non-phosphorylatable version of Y118-Paxillin increases focal adhesion disassembly and promotes cell migration in vivo, despite inhibiting cell migration in vitro. Using a mouse model, we further find that the upstream kinase, focal adhesion kinase, is downregulated in cells in vivo, and cells expressing non-phosphorylatable Y118-Paxillin exhibit increased activation of the CRKII-DOCK180/RacGEF pathway. Our findings provide significant new insight into the intrinsic regulation of focal adhesions in cells migrating in their native environment.

Discovery of novel chloropyramine-cinnamic acid hybrids as potential FAK inhibitors for intervention of metastatic triple-negative breast cancer

To search for novel focal adhesion kinase (FAK) inhibitors for intervention of metastatic triple-negative breast cancer (TNBC), a series of hybrids 7a-s from chloropyramine and cinnamic acid analogs were designed, synthesized and biologically evaluated. The most active compound 7d could potently inhibit the proliferation, invasion and migration of TNBC cells in vitro. The docking analysis of 7d was performed to elucidate its possible binding modes to focal adhesion targeting (FAT) domain of FAK scaffold. Further mechanism studies indicated the ability of 7d in disrupting Y925 autophosphorylation of FAK, reducing formation of focal adhesions (FAs) and stress fibers (SFs) as well as inducing apoptosis of TNBC cells. Together, 7d is a novel FAK inhibitor to inhibit the essential nonkinase scaffolding function of FAK via binding FAT domain and may be worth studying further for intervention of TNBC.

MicroRNA-766-3p-mediated downregulation of HNF4G inhibits proliferation in colorectal cancer cells through the PI3K/AKT pathway

Nuclear receptors (NRs) are a class of transcription factors that play a pivotal role in carcinogenesis, but their function in colorectal cancer (CRC) remains unclear. Here, we investigate the role NRs play in CRC pathogenesis. We found that hepatocyte nuclear factor 4 gamma (HNF4G; NR2A2), hepatocyte nuclear factor 4α (HNF4A; NR2A1), and retinoid-related orphan receptor γ (RORC; NR1F3) were significantly upregulated in CRC tissues analyzed by GEPIA bioinformatics tool. The expression of HNF4G was examined in CRC samples and cell lines by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Increased expression of HNF4G was strongly associated with high tumor-node-metastasis stage and poor prognosis. Moreover, overexpression of HNF4G significantly promoted the proliferation of CRC cells in vitro. Next, we found that HNF4G promoted CRC proliferation via the PI3K/AKT pathway through targeting of GNG12 and PTK2. In addition, HNF4G was verified as a direct target of microRNA-766-3p (miR-766-3p). miR-766-3p inhibited the proliferation of CRC cells by targeting HNF4G in vitro and in vivo. Collectively, our study indicates that miR-766-3p reduces the proliferation of CRC cells by targeting HNF4G expression and thus inhibits the PI3K/AKT pathway. Therefore, development of therapies which target the miR-766-3p/HNF4G axis may aid in the treatment of CRC.

Focal Adhesion Kinase Inhibitors Prevent Osteoblast Mineralization in Part Due to Suppression of Akt-mediated stabilization of Osterix

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Pharmacological blockade of FAK results in reduced ALP expression and mineralization by differentiated osteoblasts.

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Although FAK inhibition resulted in increased levels of BMP2, Wnt3a and Mdm2, and decreased p53, alteration of these pathways was unable to restore mineralization in the presence of FAK tyrosine kinase inhibitors.

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FAK tyrosine kinase inhibitors resulted in decreased levels of phospho-S473 Akt which led to increased levels of active GSK3β which in turn inhibited Runx2 activity that could contribute to the observed reduced ALP levels.

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FAK tyrosine kinase inhibitors blocked Akt-mediated stabilization of osterix leading to decreased overall levels of osterix and impaired mineralization in MC3T3-E1 cells differentiated into osteoblasts.

Focal Adhesion Kinase (FAK) is an important regulator of tumor cell proliferation, survival and metastasis. As such it has become a therapeutic target of interest in cancer. Previous studies suggested that use of FAK tyrosine kinase inhibitors (TKIs) blocks osteolysis in in vivo models of bone metastasis. However, from these studies it was not clear whether FAK TKIs blocked bone degradation by osteoclasts or also promoted bone formation by osteoblasts. In this study we evaluated whether use of the FAK TKI PF-562,271 affected the differentiation of pre-osteoblasts, or activity of mature differentiated osteoblasts. MC3T3-E1 pre-osteoblastic cells were treated with various doses of PF-562,271 following 3 or 10 days of differentiation which led to the inhibition of alkaline phosphatase (ALP) expression and reduced viable cell numbers in a dose-dependent manner. MC3T3-E1 cells which had been differentiated for 21 days prior to treatment with PF-562,271 showed a dose dependent decrease in mineralization as assessed by Alizarin Red staining, with concomitant decreased expression of ALP which is known to facilitate the bone mineralization activity of osteoblasts, however mRNA levels of the transcription factors RUNX2 and osterix which are important for osteoblast maturation and mineralization appeared unaffected at this time point. We speculated that this may be due to altered function of RUNX2 protein due to inhibitory phosphorylation by GSK3β. We found treatment with PF-562,271 resulted in increased GSK3β activity as measured by reduced levels of phospho-Ser9-GSK3β which would result in phosphorylation and inhibition of RUNX2. Treatment of 21 day differentiated MC3T3-E1 cells with PF-562,271 in combination with GSK3β inhibitors partially restored mineralization however this was not statistically significant. As we observed that FAK TKI also resulted in suppression of Akt, which is known to alter osterix protein stability downstream of RUNX2, we examined protein levels by western blot and found a dose-dependent decrease in osterix in FAK TKI treated differentiated MC3T3-E1 cells which is likely responsible for the reduced mineralization observed. Taken together our results suggest that use of FAK TKIs as therapeutics in the bone metastatic setting may block new bone formation as an off-target effect and thereby exacerbate the defective bone regulation that is characteristic of the bone metastatic environment.

FAK in Cancer: From Mechanisms to Therapeutic Strategies

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, is overexpressed and activated in many cancer types. FAK regulates diverse cellular processes, including growth factor signaling, cell cycle progression, cell survival, cell motility, angiogenesis, and the establishment of immunosuppressive tumor microenvironments through kinase-dependent and kinase-independent scaffolding functions in the cytoplasm and nucleus. Mounting evidence has indicated that targeting FAK, either alone or in combination with other agents, may represent a promising therapeutic strategy for various cancers. In this review, we summarize the mechanisms underlying FAK-mediated signaling networks during tumor development. We also summarize the recent progress of FAK-targeted small-molecule compounds for anticancer activity from preclinical and clinical evidence.

Sunitinib malate inhibits hemangioma cell growth and migration by suppressing focal adhesion kinase signaling

Sunitinib malate is a small molecule that targets multiple receptor tyrosine kinases and blocks their activity. Receptors targeted by sunitinib are implicated in tumor vascularization and are overexpressed by vascular tumors encountered in infants, namely, hemangiomas. Of note is that there is still no definitive treatment for these commonly occurring tumors of infancy. The purpose of this study was to investigate the effects of sunitinib malate on hemangioma using endothelial cells isolated from a murine model of the neoplasm (sEnd.2). The effects of the drug on cell growth were evaluated using the crystal violet assay and flow cytometry, while the scratch assay was employed to measure cell migration. Proteins associated with cell migration and angiogenesis were detected using western blotting. Sunitinib was investigated further to determine its effects on the production of reactive oxygen species, a parameter associated with the promotion of neovascularization in tumors. The results showed that sunitinib significantly reduced the growth of sEnd.2 cells by causing the cells to accumulate in the sub-G1 phase of the cell cycle, and also induced a significant decrease in the migration of these hemangioma cells (P < 0.05). The western blot assay showed a decrease in the expression of adhesion proteins, focal adhesion kinase and paxillin at IC50 doses, although the expression of cadherin did not change significantly (P < 0.05). In addition, transforming growth factor-β1 (TGF-β1) expression was decreased in sunitinib-treated cells at the same dose. The adhesion proteins as well as TGF-β1 regulate cell movement and have been implicated in tumor progression. Thus, sunitinib malate may have potential in the treatment of hemangiomas.

FAK Regulates VEGFR2 Expression and Promotes Angiogenesis in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) remains a significant clinical challenge because of its high vascularity and metastatic and recurrent rates. Tumor angiogenesis is considered an important mediator in the regulation of tumor cell survival and metastasis in TNBC. Angiogenesis is induced by the binding of vascular endothelial growth factor to vascular endothelial growth factor receptor 2 (VEGFR2). Focal adhesion kinase (FAK) plays an important role in regulating various cell functions in normal and cancer cells. Previous studies have focused on investigating the function of endothelial FAK in tumor cell angiogenesis. However, the association between tumor FAK and VEGFR2 in tumor angiogenesis and the possible mechanisms of this remain unclear. In this study, we used a public database and human specimens to examine the association between FAK and VEGFR2. At the same time, we verified the association between FAK and VEGFR2 through several experimental methods, such as quantitative real-time polymerase chain reaction, Western blotting, and next-generation sequencing. In addition, we used the endothelial cell model, zebrafish, and xenograft animal models to investigate the role of FAK in TNBC angiogenesis. We found that FAK and VEGFR2 were positively correlated in patients with TNBC. VEGFR2 and several other angiogenesis-related genes were regulated by FAK. In addition, FAK regulated VEGFR2 and VEGF protein expression in TNBC cells. Functional assays showed that FAK knockdown inhibited endothelial tube formation and zebrafish angiogenesis. An animal model showed that FAK inhibitors could suppress tumor growth and tumor vascular formation. FAK promotes angiogenesis in TNBC cells by regulating VEGFR2 expression. Therefore, targeting FAK could be another antiangiogenic strategy for TNBC treatment.

Focal adhesion kinase inhibitors, a heavy punch to cancer

Kinases are the ideal druggable targets for diseases and especially were highlighted on cancer therapy. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase and its aberrant signaling extensively implicates in the progression of most cancer types, involving in cancer cell growth, adhesion, migration, and tumor microenvironment (TME) remodeling. FAK is commonly overexpressed and activated in a variety of cancers and plays as a targetable kinase in cancer therapy. FAK inhibitors already exhibited promising performance in preclinical and early-stage clinical trials. Moreover, substantial evidence has implied that targeting FAK is more effective in combination strategy, thereby reversing the failure of chemotherapies or targeted therapies in solid tumors. In the current review, we summarized the drug development progress, chemotherapy strategy, and perspective view for FAK inhibitors.

Extracellular PKM2 facilitates organ-tissue fibrosis progression

Persistent activation of fibroblasts and resistance of myofibroblasts to turnover play important roles in organ-tissue fibrosis development and progression. The mechanism that mediates apoptosis resistance of myofibroblasts is not understood. Here, we report that myofibroblasts express and secrete PKM2. Extracellular PKM2 (EcPKM2) facilitates progression of fibrosis by protecting myofibroblasts from apoptosis. EcPKM2 upregulates arginase-1 expression in myofibroblasts and therefore facilitates proline biosynthesis and subsequent collagen production. EcPKM2 interacts with integrin αvβ3 on myofibroblasts to activate FAK-PI3K signaling axis. Activation of FAK-PI3K by EcPKM2 activates downstream NF-κB survival pathway to prevent myofibroblasts from apoptosis. On the other hand, activation of FAK- PI3K by EcPKM2 suppresses PTEN to subsequently upregulate arginase-1 in myofibroblasts. Our studies uncover an important mechanism for organ fibrosis progression. More importantly, an antibody disrupting the interaction between PKM2 and integrin αvβ3 is effective in reversing fibrosis, suggesting a possible therapeutic strategy and target for treatment of organ fibrosis.

Identification of Thieno[3,2-d]pyrimidine Derivatives as Dual Inhibitors of Focal Adhesion Kinase and FMS-like Tyrosine Kinase 3

Focal adhesion kinase (FAK) is overexpressed in highly invasive and metastatic cancers. To identify novel FAK inhibitors, we designed and synthesized various thieno[3,2-d]pyrimidine derivatives. An intensive structure-activity relationship (SAR) study led to the identification of 26 as a lead. Moreover, 26, a multitargeted kinase inhibitor, possesses excellent potencies against FLT3 mutants as well as FAK. Gratifyingly, 26 remarkably inhibits recalcitrant FLT3 mutants, including F691L, that cause drug resistance. Importantly, 26 is superior to PF-562271 in terms of apoptosis induction, anchorage-independent growth inhibition, and tumor burden reduction in the MDA-MB-231 xenograft mouse model. Also, 26 causes regression of tumor growth in the MV4-11 xenograft mouse model, indicating that it could be effective against acute myeloid leukemia (AML). Finally, in an orthotopic mouse model using MDA-MB-231, 26 remarkably prevents metastasis of orthotopic tumors to lymph nodes. Taken together, the results indicate that 26 possesses potential therapeutic value against highly invasive cancers and relapsed AML.

Na+/K+-ATPase Revisited: On Its Mechanism of Action, Role in Cancer, and Activity Modulation

Maintenance of Na⁺ and K⁺ gradients across the cell plasma membrane is an essential process for mammalian cell survival. An enzyme responsible for this process, sodium-potassium ATPase (NKA), has been currently extensively studied as a potential anticancer target, especially in lung cancer and glioblastoma. To date, many NKA inhibitors, mainly of natural origin from the family of cardiac steroids (CSs), have been reported and extensively studied. Interestingly, upon CS binding to NKA at nontoxic doses, the role of NKA as a receptor is activated and intracellular signaling is triggered, upon which cancer cell death occurs, which lies in the expression of different NKA isoforms than in healthy cells. Two major CSs, digoxin and digitoxin, originally used for the treatment of cardiac arrhythmias, are also being tested for another indication—cancer. Such drug repositioning has a big advantage in smoother approval processes. Besides this, novel CS derivatives with improved performance are being developed and evaluated in combination therapy. This article deals with the NKA structure, mechanism of action, activity modulation, and its most important inhibitors, some of which could serve not only as a powerful tool to combat cancer, but also help to decipher the so-far poorly understood NKA regulation.

Targeting Intercellular Communication in the Bone Microenvironment to Prevent Disseminated Tumor Cell Escape from Dormancy and Bone Metastatic Tumor Growth

Metastasis to the bone is a common feature of many cancers including those of the breast, prostate, lung, thyroid and kidney. Once tumors metastasize to the bone, they are essentially incurable. Bone metastasis is a complex process involving not only intravasation of tumor cells from the primary tumor into circulation, but extravasation from circulation into the bone where they meet an environment that is generally suppressive of their growth. The bone microenvironment can inhibit the growth of disseminated tumor cells (DTC) by inducing dormancy of the DTC directly and later on following formation of a micrometastatic tumour mass by inhibiting metastatic processes including angiogenesis, bone remodeling and immunosuppressive cell functions. In this review we will highlight some of the mechanisms mediating DTC dormancy and the complex relationships which occur between tumor cells and bone resident cells in the bone metastatic microenvironment. These inter-cellular interactions may be important targets to consider for development of novel effective therapies for the prevention or treatment of bone metastases.

NH2 -terminal fragment of ZF21 protein suppresses tumor invasion via inhibiting the interaction of ZF21 with FAK

Cellular migration, coupled with the degradation of the extracellular matrix (ECM), is a key step in tumor invasion and represents a promising therapeutic target in malignant tumors. Focal adhesions (FAs) and invadopodia, which are distinct actin-based cellular structures, play key roles in cellular migration and ECM degradation, respectively. The molecular machinery coordinating the dynamics between FAs and invadopodia is not fully understood, although several lines of evidence suggest that the disassembly of FAs is an important step in triggering the formation of invadopodia. In a previous study, we identified the ZF21 protein as a regulator of both FA turnover and invadopodia-dependent ECM degradation. ZF21 interacts with multiple factors for FA turnover, including focal adhesion kinase (FAK), microtubules, m-Calpain, and Src homology region 2-containing protein tyrosine phosphatase 2 (SHP-2). In particular, the dephosphorylation of FAK by ZF21 is a key event in tumor invasion. However, the precise role of ZF21 binding to FAK remains unclear. We established a method to disrupt the interaction between ZF21 and FAK using the FAK-binding NH₂ -terminal region of ZF21. Tumor cells expressing the ZF21-derived polypeptide had significantly decreased FA turnover, migration, invadopodia-dependent ECM degradation, and Matrigel invasion. Furthermore, the expression of the polypeptide inhibited an early step of experimental lung metastasis in mice. These findings indicate that the interaction of ZF21 with FAK is necessary for FA turnover as well as ECM degradation at the invadopodia. Thus, ZF21 is a potential regulator that coordinates the equilibrium between FA turnover and invadopodia activity by interacting with FAK.

Improved renal outcomes after revascularization of the stenotic renal artery in pigs by prior treatment with low-energy extracorporeal shockwave therapy

BACKGROUND

Revascularization does not restore renal function in most patients with atherosclerotic renal artery stenosis (RAS), likely because of inflammation and fibrosis within the stenotic kidney. Low-energy shockwave therapy (LE-SWT) stimulates angiogenesis in the stenotic kidney, but its ability to improve renal function and structure after revascularization remains unexplored. We tested the hypothesis that a LE-SWT regimen before percutaneous transluminal renal angioplasty (PTRA) would enable PTRA to restore renal function in hypercholesterolemic pigs with RAS (HC+RAS), and that this would be associated with attenuation of renal inflammation and fibrosis.

METHODS AND RESULTS

Twenty-six pigs were studied after 16 weeks of HC+RAS, HC+RAS treated with PTRA with or without a preceding LE-SWT regimen (bi-weekly for 3 weeks), and controls. Single-kidney renal blood flow (RBF), glomerular filtration rate (GFR), and oxygenation were assessed in vivo using imaging 4 weeks after PTRA, and then inflammation and fibrosis ex vivo.Four weeks after successful PTRA, blood pressure fell similarly in both revascularized groups. Yet, stenotic-kidney GFR remained lower in HC+RAS and HC+RAS+PTRA (P < 0.01 vs. normal), but was improved in HC+RAS+PTRA+SW (P > 0.05 vs. normal). Furthermore, reduced inflammation, medullary fibrosis, and cortical hypoxia were only shown in swine stenotic kidneys pretreated with LE-SWT before PTRA 4 weeks later.

CONCLUSION

LE-SWT delivery before revascularization permitted PTRA to improve function and decrease cortical and medullary damage in the stenotic swine kidney. This study, therefore, supports the use of an adjunct SW pretreatment to enhance the success of PTRA in blunting loss of kidney function in experimental HC+RAS.

4-hydroxy-2-nonenal decreases coronary endothelial cell migration: Potentiation by aldehyde dehydrogenase 2 inhibition

4-hydroxynonenal (4HNE) is a reactive aldehyde, which is involved in oxidative stress associated pathogenesis. The cellular toxicity of 4HNE is mitigated by aldehyde dehydrogenase (ALDH) 2. Thus, we hypothesize that ALDH2 inhibition exacerbates 4HNE-induced decrease in coronary endothelial cell (EC) migration in vitro. To test our hypothesis, we pharmacologically inhibited ALDH2 in cultured mouse coronary ECs (MCECs) by disulfiram (DSF) (2.5 μM) before challenging the cells with different doses of 4HNE (25, 50 and 75 μM) for 4, 12, 16 and 24 h. We evaluated MCEC migration by scratch wound migration assay. 4HNE attenuated MCEC migration significantly relative to control (P < .05), which was exacerbated with DSF pretreatment (P < .05). DSF pretreatment exacerbated 4HNE-induced decrease in ALDH2 activity in MCECs. Next, we showed that 75 μM 4HNE significantly decreased the intracellular mRNA levels of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), focal adhesion kinase (FAK) and other promigratory genes compared to control, which were further decreased by DSF pretreatment. 75 μM 4HNE also decreased the protein levels of VEGFR2, FAK, phospho-FAK, Src and paxillin in MCECs. Thus, we conclude that ALDH2 inhibition potentiates 4HNE-induced decrease in MCECs migration in vitro.

The Roles of Plant-Derived Triptolide on Non-Small Cell Lung Cancer

Over the past decade, natural compounds have been proven to be effective against many human diseases, including cancers. Triptolide (TPL), a diterpenoid triepoxide from the Chinese herb Tripterygium wilfordii Hook F, has exhibited attractive cytotoxic activity on several cancer cells. An increasing number of studies have emphasized the antitumor effects of TPL on non-small cell lung cancer (NSCLC). Here we mainly focused on the key molecular signaling pathways that lead to the inhibitory effects of TPL on human NSCLC, such as mitogen-activated protein kinases (MAPKs) modulation, inhibition of NF-κB activation, suppression of miRNA expression, etc. In addition, the effect of TIG on immune response in cancer patients is summarized for improved immune modulation utilization. However, the clinical use of TPL is often limited by its severe toxicity and water insolubility. Future clinical trials and drug delivery strategies that will evaluate the security and validate the underlying tumor-killing properties of TPL in human NSCLC are also to be discussed.

Inhibition of astrocyte FAK-JNK signaling promotes subventricular zone neurogenesis through CNTF

Astrocyte-derived ciliary neurotrophic factor (CNTF) promotes adult subventricular zone (SVZ) neurogenesis. We found that focal adhesion kinase (FAK) and JNK, but not ERK or P38, repress CNTF in vitro. Here, we defined the FAK-JNK pathway and its regulation of CNTF in mice, and the related leukemia inhibitory factor (LIF) and interleukin-6 (IL-6), which promote stem cell renewal at the expense of neurogenesis. Intrastriatal injection of FAK inhibitor, FAK14, in adult male C57BL/6 mice reduced pJNK and increased CNTF expression in the SVZ-containing periventricular region. Injection of a JNK inhibitor increased CNTF without affecting LIF and IL-6, and increased SVZ proliferation and neuroblast formation. The JNK inhibitor had no effect in CNTF-/- mice, suggesting that JNK inhibits SVZ neurogenesis by repressing CNTF. Inducible deletion of FAK in astrocytes increased SVZ CNTF and neurogenesis, but not LIF and IL-6. Intrastriatal injection of inhibitors suggested that P38 reduces LIF and IL-6 expression, whereas ERK induces CNTF and LIF. Intrastriatal FAK inhibition increased LIF, possibly through ERK, and IL-6 through another pathway that does not involve P38. Systemic injection of FAK14 also inhibited JNK while increasing CNTF, but did not affect P38 and ERK activation, or LIF and IL-6 expression. Importantly, systemic FAK14 increased SVZ neurogenesis in wild-type C57BL/6 and CNTF+/+ mice, but not in CNTF-/- littermates, indicating that it acts by upregulating CNTF. These data show a surprising differential regulation of related cytokines and identify the FAK-JNK-CNTF pathway as a specific target in astrocytes to promote neurogenesis and possibly neuroprotection in neurological disorders.

Disassembling a cancer puzzle: Cell junctions and plasma membrane as targets for anticancer therapy

Despite an enhanced permeability and retention effect typical of many solid tumors, drug penetration is not always sufficient. Possible strategies for the drug delivery improvement are a modification of the tumor cell-to-cell junctions and usage of cell membrane permeabilization proteins. In this review we discuss epithelial cell junctions as targets for a combined anticancer therapy and propose new possible sources of such agents. We suggest considering viral and bacterial pathogens disrupting epithelial layers as plentiful sources of new therapeutic agents for increasing tumor permeability for other effector agents. We also observe the application of pore forming proteins and peptides of different origin for cytoplasmic delivery of anti-cancer agents and consider the main obstacles of their use in vivo.

Collagen Fiber Orientation Regulates 3D Vascular Network Formation and Alignment

Alignment of collagen type I fibers is a hallmark of both physiological and pathological tissue remodeling. However, the effects of collagen fiber orientation on endothelial cell behavior and vascular network formation are poorly understood because of a lack of model systems that allow studying these potential functional connections. By casting collagen type I into prestrained (0, 10, 25, 50% strain), poly(dimethylsiloxane) (PDMS)-based microwells and releasing the mold strain following polymerization, we have created collagen gels with varying fiber alignment as confirmed by structural analysis. Endothelial cells embedded within the different gels responded to increased collagen fiber orientation by assembling into 3D vascular networks that consisted of thicker, more aligned branches and featured elevated collagen IV deposition and lumen formation relative to control conditions. These substrate-dependent changes in microvascular network formation were associated with altered cell division and migration patterns and related to enhanced mechanosignaling. Our studies indicate that collagen fiber alignment can directly regulate vascular network formation and that culture models with aligned collagen may be used to investigate the underlying mechanisms ultimately advancing our understanding of tissue development, homeostasis, and disease.

Novel benzotriazole N-acylarylhydrazone hybrids: Design, synthesis, anticancer activity, effects on cell cycle profile, caspase-3 mediated apoptosis and FAK inhibition

A series of novel benzotriazole N-acylarylhydrazone hybrids was synthesized according fragment-based design strategy. All the synthesized compounds were evaluated for their anticancer activity against 60 human tumor cell lines by NCI (USA). Five compounds: 3d, 3e, 3f, 3o and 3q exhibited significant to potent anticancer activity at low concentrations. Compound 3q showed the most prominent broad-spectrum anticancer activity against 34 tumor cell lines, with mean growth inhibition percent of 45.80%. It exerted the highest potency against colon HT-29 cell line, with cell growth inhibition 86.86%. All leukemia cell lines were highly sensitive to compound 3q. Additionally, compound 3q demonstrated lethal activity to MDA-MB-435 belonging melanoma. Compound 3e exhibited the highest anticancer activity against leukemic CCRF-CEM and HL-60(TB) cell lines, with cell growth inhibition 86.69% and 86.42%, respectively. Moreover, it exerted marked potency against ovarian OVCAR-3 cancer cell line, with cell growth inhibition 78.24%. Four compounds: 3d, 3e, 3f and 3q were further studied through determination of IC₅₀ values against the most sensitive cancer cell lines. The four compounds exhibited highly potent anticancer activity against ovarian cancer OVCAR-3 and leukemia HL-60 (TB) cell lines, with IC₅₀ values in nano-molar range between 25 and 130 nM. They showed 18-2.3 folds more potent anticancer activity than doxorubicin. The most prominent compound was 3e, (IC₅₀ values 29 and 25 nM against OVCAR-3 and HL-60 (TB) cell lines, respectively), representing 10 and 18 folds more potency than doxorubicin. The anti-proliferative activity of these four compounds appeared to correlate well with their ability to inhibit FAK at nano-molar range between 44.6 and 80.75 nM. Compound 3e was a potent, inhibitor of FAK and Pyk2 activity with IC₅₀ values of 44.6 and 70.19 nM, respectively. It was 1.6 fold less potent for Pyk2 than FAK. Additionally, it displayed inhibition in cell based assay measuring phosphorylated-FAK (IC₅₀ = 32.72 nM). Inhibition of FAK enzyme led to a significant increase in the level of active caspase-3, compared to control (11.35 folds), accumulation of cells in pre-G1 phase and annexin-V and propidium iodide staining in addition to cell cycle arrest at G2/M phase indicating that cell death proceeded through an apoptotic mechanism.

Attenuation of murine acute lung injury by PF-573,228, an inhibitor of focal adhesion kinase

Acute lung injury (ALI) is characterized by endothelial barrier disruption resulting in increased vascular permeability. As focal adhesion kinase (FAK), a non-receptor protein tyrosine kinase, is involved in endothelial cell (EC) barrier regulation, we hypothesized that FAK inhibition could attenuate agonist-induced EC barrier disruption relevant to ALI. Human lung EC were pretreated with one of three pharmacologic FAK inhibitors, PF-573,228 (PF-228, 10 μM), PF-562,271 (PF-271, 5 μM) or NVP-TAE226 (TAE226, 5 μM) for 30 min prior to treatment with thrombin (1 U/ml, 30 min). Western blotting confirmed attenuated thrombin-induced FAK phosphorylation associated with all three inhibitors. Subsequently, EC were pretreated with either PF-228 (10 μM), TAE226 (5 μM) or PF-271 (5 μM) for 30 min prior to thrombin stimulation (1 U/ml) followed by measurements of barrier integrity by transendothelial electrical resistance (TER). Separately, EC grown in transwell inserts prior to thrombin (1 U/ml) with measurements of FITC-dextran flux after 30 min confirmed a significant attenuation of thrombin-induced EC barrier disruption by PF-228 alone. Finally, in a murine ALI model induced by LPS (1.25 mg/ml, IT), rescue treatment with PF-228 was associated with significantly reduced lung injury. Our findings PF-228, currently being studied in clinical trials, may serve as a novel and effective therapeutic agent for ALI.

Gefitinib or lapatinib with foretinib synergistically induce a cytotoxic effect in melanoma cell lines

Melanoma is an aggressive cancer type with a high mortality rate and an elevated resistance to conventional treatment. Recently, promising new tools for anti-melanoma targeted therapy have emerged including inhibitors directed against frequently overexpressed receptors of growth factors implicated in the progression of this cancer. The ineffectiveness of single-targeted therapy prompted us to study the efficacy of treatment with a combination of foretinib, a MET (hepatocyte growth factor receptor) inhibitor, and gefitinib or lapatinib, EGFR (epidermal growth factor receptor) inhibitors. We observed a synergistic cytotoxic effect for the combination of foretinib and lapatinib on the viability and proliferation of the examined melanoma cell lines. This combination of inhibitors significantly decreased Akt and Erk phosphorylation, while the drugs used independently were insufficient. Additionally, after treatment with pairs of inhibitors, cells became larger, with more pronounced stress fibers and abnormally shaped nuclei. We also noticed the appearance of polyploid cells and massive enrichment in the G2/M phase. Therefore, combination treatment was much more effective against melanoma cells than a single-targeted approach. Based on our results, we conclude that both EGFR and MET receptors might be effective targets in melanoma therapy. However, variation in their levels in patients should be taken into consideration.

Stressful Surfaces: Cell Metabolism on a Poorly Adhesive Substrate

The adhesion and proliferation of cells are exquisitely sensitive to the nature of the surface to which they attach. Aside from cell counting, cell "health" on surfaces is typically established by measuring the metabolic rate with dyes that participate in the metabolic pathway or using "live/dead" assays with combinations of membrane permeable/impermeable dyes. The binary information gleaned from these tests-whether cells are attached or not, and whether they are living or dead-provides an incomplete picture of cell health. In the present work, proliferation rates and net metabolism of 3T3 fibroblasts seeded on "biocompatible" ultrathin polyelectrolyte multilayer films and on control tissue culture plastic were compared. Cells adhered to, and proliferated on, both surfaces, which were shown to be nontoxic according to live/dead assays. However, adhesion was poorer on the multilayer surface, illustrated by diffuse organization of the actin cytoskeleton and less-developed focal adhesions. Proliferation was also slower on the multilayer. When normalized for the total number of cells, it was shown that cells on multilayers experienced a five-day burst of metabolic stress, after which the metabolic rate approached that of the control surface. This initial state of high stress has not been reported or appreciated in studies of cell growth on multilayers, although the observation period for this system is usually a few days.

Focal adhesion kinase a potential therapeutic target for pancreatic cancer and malignant pleural mesothelioma

The non-receptor cytoplasmic tyrosine kinase, Focal Adhesion Kinase (FAK) is known to play a key role in a variety of normal and cancer cellular functions such as survival, proliferation, migration and invasion. It is highly active and overexpressed in various cancers including Pancreatic Ductal Adenocarcinoma (PDAC) and Malignant Pleural Mesothelioma (MPM). Here, initially, we demonstrate that FAK is overexpressed in both PDAC and MPM cell lines. Then we analyze effects of two small molecule inhibitors PF-573228, and PF-431396, which are dual specificity inhibitors of FAK and proline rich tyrosine kinase 2 (PYK2), as well as VS-6063, another small molecule inhibitor that specifically inhibits FAK but not PYK2 for cell growth, motility and invasion of PDAC and MPM cell lines. Treatment with PF-573228, PF-431396 and VS-6063 cells resulted in a dose-dependent inhibition of growth and anchorage-independent colony formation in both cancer cell lines. Furthermore, these compounds suppressed the phosphorylation of FAK at its active site, Y397, and functionally induced significant apoptosis and cell cycle arrest in both cell lines. Using the ECIS (Electric cell-substrate impedance sensing) system, we found that treatment of both PF compounds suppressed adherence and migration of PDAC cells on fibronectin. Interestingly, 3D-tumor organoids derived from autochthonous KC (Kras;PdxCre) mice treated with PF-573228 revealed a significant decrease in tumor organoid size and increase in organoid cell death. Taken together, our results show that FAK is an important target for mesothelioma and pancreatic cancer therapy that merit further translational studies.

A Metabolomics Pilot Study on Desmoid Tumors and Novel Drug Candidates

Desmoid tumors (aggressive fibromatosis) are locally invasive soft tissue tumors that lack the ability to metastasize. There are no directed therapies or standard treatment plan, and chemotherapeutics, radiation, and surgery often have temporary effects. The majority of desmoid tumors are related to T41A and S45F mutations of the beta-catenin encoding gene (CTNNB1). Using broad spectrum metabolomics, differences were investigated between paired normal fibroblast and desmoid tumor cells from affected patients. There were differences identified, also, in the metabolomics profiles associated with the two beta-catenin mutations, T41A and S45F. Ongoing drug screening has identified currently available compounds which inhibited desmoid tumor cellular growth by more than 50% but did not affect normal fibroblast proliferation. Two drugs were investigated in this study, and Dasatinib and FAK Inhibitor 14 treatments resulted in unique metabolomics profiles for the normal fibroblast and desmoid tumor cells, in addition to the T41A and S45F. The biochemical pathways that differentiated the cell lines were aminoacyl-tRNA biosynthesis in mitochondria and cytoplasm and signal transduction amino acid-dependent mTORC1 activation. This study provides preliminary understanding of the metabolic differences of paired normal and desmoid tumors cells, their response to desmoid tumor therapeutics, and new pathways to target for therapy.

Design, synthesis and biological evaluation of sulfonamide-substituted diphenylpyrimidine derivatives (Sul-DPPYs) as potent focal adhesion kinase (FAK) inhibitors with antitumor activity

A class of sulfonamide-substituted diphenylpyrimidines (Sul-DPPYs) were synthesized to improve activity against the focal adhesion kinase (FAK). Most of these new Sul-DPPYs displayed moderate activity against the FAK enzyme with IC₅₀ values of less than 100nM; regardless, they could effectively inhibit several classes of refractory cancer cell lines with IC₅₀ values of less than 10µM, including the pancreatic cancer cell lines (AsPC-1, Panc-1 and BxPC-3), the NSCLC-resistant H1975 cell line, and the B lymphocyte cell line (Ramos cells). Results of flow cytometry indicated that inhibitor 7e promoted apoptosis of pancreatic cancer cells in a dose-dependent manner. In addition, it almost completely induced the apoptosis at a concentration of 10µM. Compound 7e may be selected as a potent FAK inhibitor for the treatment of pancreatic cancer.

Synthesis of novel 1,2,4-triazine scaffold as FAK inhibitors with antitumor activity

A series of 1,3,5-triazinic inhibitors of focal adhesion kinase (FAK) has recently been shown to exert antiangiogenic activity against HUVEC cells and anticancer efficacy against several cancer cell lines. In this report, we designed and synthesized a series of new compounds containing a 1,2,4-triazine core as novel scaffold for FAK inhibitors. These compounds displayed 10^-7M IC₅₀ values, and the best one showed IC₅₀ value of 0.23μM against FAK enzymatic activity. Among them, several inhibitors potently inhibited the proliferation of glioblastoma (U-87MG) and colon (HCT-116) cancer cell lines. Docking of compound 10 into the active site of the FAK kinase was performed to explore its potential binding mode.

KCNMA1 cooperating with PTK2 is a novel tumor suppressor in gastric cancer and is associated with disease outcome

BACKGROUND

Inactivation of tumor suppressor genes by promoter hypermethylation plays a key role in the tumorgenesis. It is necessary to uncover the detailed pattern of whole genome-wide abnormal DNA methylation during the development of gastric cancer (GC).

METHOD

We performed a genome-wide methylation detection using 12 paired of GC tissues and their corresponding normal tissues. Methylation-specific PCR (MSP) and bisulphite sequencing (BSP) were used to measure methylation status of specific CpG site. Based on the bioinformatic analysis, the cell phenotypes and mouse model experiments were constructed to detect effect of the target gene. Using the Kaplan-Meier survival curve, the clinical value of KCNMA1 was assessed in GC patients.

RESULTS

The CpG site cg24113782 located at the promoter of KCNMA1 showed the most significant difference, contributing to the commonly silenced KCNMA1in gastric cancer cells and primary GC tissues. The promoter methylation of KCNMA1 was detected in 68.7% (77/112) of tumor tissues, compared with 16.2% (18/112) of normal tissues (P < 0.001). The survival curve indicated that KCNMA1 hypermethylation was significantly associated with the shortened survival in GC patients (P = 0.036). KCNMA1 significantly inhibited biological malignant behavior of gastric cancer cell by inducing cell apoptosis in vitro, and suppressed xenograft tumor growth in subcutaneous mouse models (both P < 0.001). Furthermore, the anti-tumor effect of KCNMA1was mediated through suppressing the expression of PTK2.

CONCLUSION

KCNMA1 is a critical tumor suppressor in gastric carcinogenesis and its hypermethylation is an independent prognostic factor in patients with gastric cancer.

Synthesis and evaluation of novel F-18-labeled pyrimidine derivatives: potential FAK inhibitors and PET imaging agents for cancer detection

Compound [¹⁸F]-8a exhibited good in vivo biodistribution data in mice bearing S180 tumor. And the microPET imaging study of [¹⁸F]-8a in S180 tumor-bearing mice was also preformed, which illustrated that the uptake in S180 tumor at 60 min post-injection of [¹⁸F]-8a was obvious.

Integrin-FAK signaling rapidly and potently promotes mitochondrial function through STAT3

Background

STAT3 is increasingly becoming known for its non-transcriptional regulation of mitochondrial bioenergetic function upon activation of its S727 residue (S727-STAT3). Lengthy mitochondrial dysfunction can lead to cell death. We tested whether an integrin-FAK-STAT3 signaling pathway we recently discovered regulates mitochondrial function and cell survival, and treatments thereof.

Methods

Cultured mouse brain bEnd5 endothelial cells were treated with integrin, FAK or STAT3 inhibitors, FAK siRNA, as well as integrin and STAT3 activators. STAT3 null cells were transfected with mutant STAT3 plasmids. Outcome measures included oxygen consumption rate for mitochondrial bioenergetics, Western blotting for protein phosphorylation, mitochondrial membrane potential for mitochondrial integrity, ROS production, and cell counts.

Results

Vitronectin-dependent mitochondrial basal respiration, ATP production, and maximum reserve and respiratory capacities were suppressed within 4 h by RGD and αvβ3 integrin antagonist peptides. Conversely, integrin ligands vitronectin, laminin and fibronectin stimulated mitochondrial function. Pharmacological inhibition of FAK completely abolished mitochondrial function within 4 h while FAK siRNA treatments confirmed the specificity of FAK signaling. WT, but not S727A functionally dead mutant STAT3, rescued bioenergetics in cells made null for STAT3 using CRISPR-Cas9. STAT3 inhibition with stattic in whole cells rapidly reduced mitochondrial function and mitochondrial pS727-STAT3. Stattic treatment of isolated mitochondria did not reduce pS727 whereas more was detected upon phosphatase inhibition. This suggests that S727-STAT3 is activated in the cytoplasm and is short-lived upon translocation to the mitochondria. FAK inhibition reduced pS727-STAT3 within mitochondria and reduced mitochondrial function in a non-transcriptional manner, as shown by co-treatment with actinomycin. Treatment with the small molecule bryostatin-1 or hepatocyte growth factor (HGF), which indirectly activate S727-STAT3, preserved mitochondrial function during FAK inhibition, but failed in the presence of the STAT3 inhibitor. FAK inhibition induced loss of mitochondrial membrane potential, which was counteracted by bryostatin, and increased superoxide and hydrogen peroxide production. Bryostatin and HGF reduced the substantial cell death caused by FAK inhibition over a 24 h period.

Conclusion

These data suggest that extracellular matrix molecules promote STAT3-dependent mitochondrial function and cell survival through integrin-FAK signaling. We furthermore show a new treatment strategy for cell survival using S727-STAT3 activators.

Focal adhesion kinase is required for actin polymerization and remodeling of the cytoskeleton during sperm capacitation

Several focal adhesion proteins are known to cooperate with integrins to link the extracellular matrix to the actin cytoskeleton; as a result, many intracellular signaling pathways are activated and several focal adhesion complexes are formed. However, how these proteins function in mammalian spermatozoa remains unknown. We confirm the presence of focal adhesion proteins in guinea pig spermatozoa, and we explore their role during capacitation and the acrosome reaction, and their relationship with the actin cytoskeleton. Our results suggest the presence of a focal adhesion complex formed by β1-integrin, focal adhesion kinase (FAK), paxillin, vinculin, talin, and α-actinin in the acrosomal region. Inhibition of FAK during capacitation affected the protein tyrosine phosphorylation associated with capacitation that occurs within the first few minutes of capacitation, which caused the acrosome reaction to become increasingly Ca²⁺ dependent and inhibited the polymerization of actin. The integration of vinculin and talin into the complex, and the activation of FAK and paxillin during capacitation, suggests that the complex assembles at this time. We identify that vinculin and α-actinin increase their interaction with F-actin while it remodels during capacitation, and that during capacitation focal adhesion complexes are structured. FAK contributes to acrosome integrity, likely by regulating the polymerization and the remodeling of the actin cytoskeleton.

Summary: We describe the role of FAK and focal adhesion proteins in capacitation, acrosome reaction, polymerization and remodeling of actin cytoskeleton, and how inhibition of FAK affects sperm physiology.

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.

Focal Adhesion Kinase Inhibitors in Combination with Erlotinib Demonstrate Enhanced Anti-Tumor Activity in Non-Small Cell Lung Cancer

Blockade of epidermal growth factor receptor (EGFR) activity has been a primary therapeutic target for non-small cell lung cancers (NSCLC). As patients with wild-type EGFR have demonstrated only modest benefit from EGFR tyrosine kinase inhibitors (TKIs), there is a need for additional therapeutic approaches in patients with wild-type EGFR. As a key component of downstream integrin signalling and known receptor cross-talk with EGFR, we hypothesized that targeting focal adhesion kinase (FAK) activity, which has also been shown to correlate with aggressive stage in NSCLC, would lead to enhanced activity of EGFR TKIs. As such, EGFR TKI-resistant NSCLC cells (A549, H1299, H1975) were treated with the EGFR TKI erlotinib and FAK inhibitors (PF-573,228 or PF-562,271) both as single agents and in combination. We determined cell viability, apoptosis and 3-dimensional growth in vitro and assessed tumor growth in vivo. Treatment of EGFR TKI-resistant NSCLC cells with FAK inhibitor alone effectively inhibited cell viability in all cell lines tested; however, its use in combination with the EGFR TKI erlotinib was more effective at reducing cell viability than either treatment alone when tested in both 2- and 3-dimensional assays in vitro, with enhanced benefit seen in A549 cells. This increased efficacy may be due in part to the observed inhibition of Akt phosphorylation when the drugs were used in combination, where again A549 cells demonstrated the most inhibition following treatment with the drug combination. Combining erlotinib with FAK inhibitor was also potent in vivo as evidenced by reduced tumor growth in the A549 mouse xenograft model. We further ascertained that the enhanced sensitivity was irrespective of the LKB1 mutational status. In summary, we demonstrate the effectiveness of combining erlotinib and FAK inhibitors for use in known EGFR wild-type, EGFR TKI resistant cells, with the potential that a subset of cell types, which includes A549, could be particularly sensitive to this combination treatment. As such, further evaluation of this combination therapy is warranted and could prove to be an effective therapeutic approach for patients with inherent EGFR TKI-resistant NSCLC.

Repulsive guidance molecule A suppresses angiogenesis

The repulsive guidance molecule-a (RGMa) is a membrane-associated glycoprotein that has diverse functions in the developing and adult central nervous system. Here, we show that RGMa suppresses new blood vessel formation. Treatment of human umbilical artery endothelial cells (HUAEC) on Matrigel with recombinant RGMa inhibits vascular endothelial growth factor (VEGF)-induced and VEGF-independent tubular formation and migration. RGMa enhances adhesion presumably through dephosphorylation of focal adhesion kinase (FAK) at tyrosine-397. Neogenin, an RGMa receptor, in HUAEC is required for the effect of RGMa. In vivo Matrigel plug assay reveals that treatment with recombinant RGMa suppresses angiogenesis. Thus, we conclude that RGMa inhibits angiogenesis in vitro and in vivo suggesting that its manipulation would be an efficient therapeutic strategy for pro-angiogenic conditions.

Targeting of proangiogenic signalling pathways in chronic inflammation

Angiogenesis is de novo capillary outgrowth from pre-existing blood vessels. This process not only is crucial for normal development, but also has an important role in supplying oxygen and nutrients to inflamed tissues, as well as in facilitating the migration of inflammatory cells to the synovium in rheumatoid arthritis, spondyloarthritis and other systemic autoimmune diseases. Neovascularization is dependent on the balance of proangiogenic and antiangiogenic mediators, including growth factors, cytokines, chemokines, cell adhesion molecules and matrix metalloproteinases. This Review describes the various intracellular signalling pathways that govern these angiogenic processes and discusses potential approaches to interfere with pathological angiogenesis, and thereby ameliorate inflammatory disease, by targeting these pathways.

Genome-Wide Gene Expression Analysis Identifies the Proto-oncogene Tyrosine-Protein Kinase Src as a Crucial Virulence Determinant of Infectious Laryngotracheitis Virus in Chicken Cells

Given the side effects of vaccination against infectious laryngotracheitis (ILT), novel strategies for ILT control and therapy are urgently needed. The modulation of host-virus interactions is a promising strategy to combat the virus; however, the interactions between the host and avian ILT herpesvirus (ILTV) are unclear. Using genome-wide transcriptome studies in combination with a bioinformatic analysis, we identified proto-oncogene tyrosine-protein kinase Src (Src) to be an important modulator of ILTV infection. Src controls the virulence of ILTV and is phosphorylated upon ILTV infection. Functional studies revealed that Src prolongs the survival of host cells by increasing the threshold of virus-induced cell death. Therefore, Src is essential for viral replication in vitro and in ovo but is not required for ILTV-induced cell death. Furthermore, our results identify a positive-feedback loop between Src and the tyrosine kinase focal adhesion kinase (FAK), which is necessary for the phosphorylation of either Src or FAK and is required for Src to modulate ILTV infection. To the best of our knowledge, we are the first to identify a key host regulator controlling host-ILTV interactions. We believe that our findings have revealed a new potential therapeutic target for ILT control and therapy.

IMPORTANCE

Despite the extensive administration of live attenuated vaccines starting from the mid-20th century and the administration of recombinant vaccines in recent years, infectious laryngotracheitis (ILT) outbreaks due to avian ILT herpesvirus (ILTV) occur worldwide annually. Presently, there are no drugs or control strategies that effectively treat ILT. Targeting of host-virus interactions is considered to be a promising strategy for controlling ILTV infections. However, little is known about the mechanisms governing host-ILTV interactions. The results from our study advance our understanding of host-ILTV interactions on a molecular level and provide experimental evidence that it is possible to control ILT via the manipulation of host-virus interactions.

Combination of heat shock protein 90 and focal adhesion kinase inhibitors synergistically inhibits the growth of non-small cell lung cancer cells

Discovery of effective drug combinations is a promising strategy to improve patient survival. This study explores the impact of heat shock protein 90 (Hsp90) inhibition in combination with focal adhesion kinase (FAK) inhibitor on the growth of non-small cell lung cancer cells (NSCLC cells). Our data show that 17-N-Allylamino-17-demethoxygeldanamycin (17-AAG), a well-studied Hsp90 inhibitor, synergized with FAK inhibitor, PF-573228, on the growth inhibition of NSCLC cells. This combination effect was confirmed using additional chemically distinct Hsp90 inhibitor, STA-9090, which is currently undergoing phase 3 clinical evaluation. Co-treatment of NSCLC cells with Hsp90 and FAK inhibitors significantly enhanced the inhibition on long-term colony formation compared to that with single agent. Inhibition of FAK exacerbated the G₂ cell cycle arrest and annexin-V apoptotic staining induced by 17-AAG. Further mechanistic studies revealed that the combination of Hsp90 and FAK inhibitors reduced the activity of canonical proliferative and survival Akt-mTOR signaling, and increased pro-apoptotic caspase activation. Interestingly, FAK inhibition alone induced feedback activation of pro-survival Erk signaling, which was abrogated by co-treatment with Hsp90 inhibitors. Both Hsp90 and FAK inhibitors are undergoing clinical evaluation. Our studies suggest the tandem of Hsp90 and FAK inhibitors may provide an effective treatment option for NSCLC patients.

Cellular fibronectin 1 promotes VEGF-C expression, lymphangiogenesis and lymph node metastasis associated with human oral squamous cell carcinoma

Lymph node metastasis (LNM) is associated with poor survival in patients with oral squamous cell carcinoma (OSCC). Vascular endothelial growth factor-C (VEGF-C) is thought to be responsible for increased lymphangiogenesis and LNM. Understanding of the mechanism by which VEGF-C expression is regulated in OSCC is thus important to design logic therapeutic interventions. We showed that inoculation of the SAS human OSCC cells expressing the venus GFP (V-SAS cells) into the tongue in nude mice developed LNM. V-SAS cells in LNM were isolated by FACS and re-inoculated into the tongue. This procedure was repeated eight times, establishing V-SAS-LM8 cells. Differential metastasis PCR array between the parental V-SAS and V-SAS-LM8 was performed to identify a molecule responsible for lymphangiogenesis and LNM. Fibronectin 1 (FN1) expression was elevated in V-SAS-LM8 cells compared to V-SAS-cells. V-SAS-LM8 tongue tumor showed increased expression of FN1 and VEGF-C, and promoted lymphangiogenesis and LNM compared with V-SAS tumor. Further, phosphorylation of focal adhesion kinase (FAK), a main downstream signaling molecule of FN1, was up-regulated, and epithelial-mesenchymal transition (EMT) was promoted in V-SAS-LM8 cells. Silencing of FN1 by shRNA in V-SAS-LM8 cells decreased FAK phosphorylation, VEGF-C expression and inhibited lymphangiogenesis and LNM. EMT was also reversed. The FAK phosphorylation inhibitor PF573228 also decreased VEGF-C expression and reversed EMT in V-SAS-LM8 cells. Finally, we detected intense FN1 expression in some clinical specimens obtained from OSCC patients with LNM. These results demonstrate that elevated expression of cellular FN1 and following activation of FAK lead to increased VEGF-C expression, lymphangiogenesis and LNM and promoted EMT in SAS human OSCC cells and suggest that FN1-phosphorylated FAK signaling cascade is a potential therapeutic target in the treatment of LNM in OSCC.

Triptolide Inhibits Lung Cancer Cell Migration, Invasion, and Metastasis

BACKGROUND

Triptolide is an extract from Tripterygium wilfordii used in traditional Chinese medicine to treat autoimmune disorders. Triptolide has anticancer effects in vitro and is reported to impair cancer cell migration. We studied whether triptolide inhibits lung cancer cell migration and metastasis.

METHODS

We determined the microRNA expression profile of triptolide-treated cells. We tested the effects of triptolide treatment on migration and invasion of lung cancer cells by using Transwell filters coated with fibronectin and Matrigel, respectively. Western blot analyses were used to compare expression of proteins involved in cell migration before and after 10 nmol/L triptolide treatment. Tail vein injections with H358 cells were performed. The mice were treated with 1 mg/kg triptolide or vehicle by intraperitoneal injection three times per week. Lung and liver metastases were compared at 9 weeks. Means of groups were compared by using a t test.

RESULTS

Triptolide altered the expression of microRNAs involved in cellular movement and significantly decreased migration and invasion of lung cancer cells from approximately 18 to 3 cells per field (p < 0.001). Triptolide decreases focal adhesion kinase expression, which leads to impairment of downstream signaling. Finally, triptolide-treated mice injected with lung cancer cells significantly decreased metastatic colony formation in the lungs (p < 0.01).

CONCLUSIONS

Triptolide decreases lung cancer cell migration and invasion in vitro and inhibits metastatic tumor formation in mice. Triptolide suppresses focal adhesion kinase, which causes deregulation of the migration machinery. These results suggest that triptolide inhibits lung cancer metastasis and should be investigated as a new lung cancer therapy.

High basal Wnt signaling is further induced by PI3K/mTor inhibition but sensitive to cSRC inhibition in mammary carcinoma cell lines with HER2/3 overexpression

Background

Elevated basal, ligand-independent, Wnt signaling in some canine breast cancer cells is not caused by classical mutations in APC, β-Catenin or GSK3β but, at least partially, by enhanced LEF1 expression. We examined the expression and function of EGFR/HER-regulated pathways on the ligand-independent Wnt signaling.

Methods

Twelve canine mammary tumor cell lines with previously reported differential basal Wnt activity were used. The expression levels of genes related to EGF-signaling were analyzed by cluster analysis. Cell lines with a combined overexpression of EGF-related genes and enhanced basal Wnt activity were treated with PI3K/mTor or cSRC inhibitors or transfected with a construct expressing wild-type PTEN. Subsequently, effects were measured on Wnt activity, cell proliferation, gene expression and protein level.

Results

High basal Wnt/LEF1 activity was associated with overexpression of HER2/3, ID1, ID2, RAC1 and HSP90 together with low to absent cMET and PTEN mRNA expression, suggesting a connection between Wnt- and HER-signaling pathways. Inhibition of the HER-regulated PI3K/mTor pathway using the dual PI3K/mTor inhibitor BEZ235 or the mTor inhibitor Everolimus® resulted in reduced cell proliferation. In the cell line with high basal Wnt activity, however, an unexpected further increased Wnt activity was found that could be greatly reduced after inhibition of the HER-regulated cSRC activity. Inhibition of the PI3K/mTor pathway was associated with enhanced expression of β-Catenin, Axin2, MUC1, cMET, EGFR and HER2 and a somewhat increased β-Catenin protein content, whereas cSRC inhibition was associated with slightly enhanced HER3 and SLUG mRNA expression. A high protein expression of HER3 was found only in a cell line with high basal Wnt activity.

Conclusions

High basal Wnt activity in some mammary cancer cell lines is associated with overexpression of HER-receptor related genes and HER3 protein, and the absence of PTEN. Inhibition of the PI3K/mTor pathway further stimulated, however, canonical Wnt signaling, whereas the inhibitory effect with the cSRC inhibitor Src-I1 on the Wnt activity further suggested a connection between Wnt and HER2/3-signaling.

Focal adhesion kinase and p53 synergistically decrease neuroblastoma cell survival

Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of neuroblastoma tumor development and progression. The p53 oncogene, although wild type in most neuroblastomas, lacks significant function as a tumor suppressor in these tumors. Recent reports have found that FAK and p53 interact in some tumor types. We have hypothesized FAK and p53 coordinately control each other's expression and also interact in neuroblastoma. In the present study, we showed that not only do FAK and p53 interact but each one controls the expression of the other. In addition, we also examined the effects of FAK inhibition combined with p53 activation in neuroblastoma and showed that these two, in combination, had a synergistic effect on neuroblastoma cell survival. The findings from this present study help to further our understanding of the regulation of neuroblastoma tumorigenesis and may provide novel therapeutic strategies and targets for neuroblastoma and other pediatric solid tumors.