In Vitro | In vitro activity: GSK2256098 is a small molecule developed by GlaxoSmithKline) as a selective FAK (Focal Adhesion Kinase) kinase inhibitor to inhibit FAK activity through targeting the phosphorylation site of FAK, tyrosine (Y) 397. GSK2256098 inhibits growth and survival of pancreatic ductal adenocarcinoma cells. It is a thousand fold more selective for FAK compared to the nearest FAK family member, Pyk2. GSK2256098 inhibits FAK activity through targeting the phosphorylation site of FAK, tyrosine (Y) 397. Treatment with GSK2256098 resulted in greater inhibition of pFAK(Y397) in PTEN-mutated (Ishikawa) than in PTEN-wild-type (Hec1A) cells. Ishikawa cells were more sensitive to GSK2256098 than the treated Hec1A cells. Ishikawa cells were transfected with a wild-type PTEN construct and pFAK(Y397) expression was unchanged after treatment with GSK2256098. Decreased cell viability and enhanced sensitivity to chemotherapy (paclitaxel and topotecan) in combination with GSK2256098 was observed in Ishikawa cells as compared with Hec1a cells.
Kinase Assay: GSK2256098 is a thousand fold more selective for FAK compared to the nearest FAK family member, Pyk2. GSK2256098 inhibits FAK activity through targeting the phosphorylation site of FAK, tyrosine (Y) 397. GSK2256098 inhibits FAK activity or Y397 phosphorylation in cancer cell lines, OVCAR8 (ovary), U87MG (brain), and A549 (lung), at IC50s of 15, 8.5 and 12 nM, respectively.
Cell Assay: PDAC cells are cultured on a 6-well plate. When cell confluence reachs about 70% in regular medium, the cells are incubated in the medium containing 0.1-10 μM GSK2256098 for 48 or 72 hr. At the end of treatments, cells are re-seeded and kept for 9 d Then, the cells are stained using Clonogenic Reagent, and the blue colonies are counted.GSK2256098 has been developed to inhibit FAK activity through targeting the phosphorylation site of FAK, tyrosine (Y) 397. After a 30-min incubation, GSK2256098 inhibits FAK activity or Y397 phosphorylation in cancer cell lines, OVCAR8 (ovary), U87MG (brain), and A549 (lung), at IC50 values of 15, 8.5 and 12 nM, respectively. In addition, the data suggests that cellular inhibition of FAK by GSK2256098 can occur as early as 30 min in cultured cells and lasts up to 12 hours in mouse tumor xenografts. GSK2256098 inhibition of FAK kinase activity can decrease Akt and ERK activity. PI3K/Akt and ERK signaling contributes to cell survival, implying a pharmacological value of GSK2256098 in attenuation of abnormal survival pathways in specific types of PDAC cells. GSK2256098 can promote apoptosis in L3.6P1 cells through caspase-9/PARP-related pathways. It attenuates abnormal growth and aberrant motility of PDAC cells in a FAK specific manner. |
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In Vivo | Pharmacokinetic (PK) studies in mice and rats with an intact blood brain barrier indicate that the penetration of GSK2256098 into the CNS is poor. However, it achieves concentrations in tumor of patients with GBM(glioblastoma) exceeding those associated with preclinical activity.In the Ishikawa orthoptopic murine model, treatment with GSK2256098 results in lower tumor weights and fewer metastases than mice inoculated with Hec1A cells. Tumors treated with GSK2256098 have lower microvessel density (CD31), less cellular proliferation (Ki67), and higher apoptosis (TUNEL) rates in the Ishikawa model when compared to the Hec1a model. GSK2256098 may be therapeutically beneficial to patients with PTEN-mutant uterine cancer, and PTEN represents a potential predictive biomarker. FAK is well-known to play an important role in angiogenesis, proliferation, and apoptosis, so the tumor samples harvested from the therapy experiments are examined. Evaluating CD31, significantly lower microvessel densities in tumors from mice treated with GSK2256098 and Paclitaxel is observed than in tumors from mice in the vehicle control group (P<0.05). This is consistent across both models, but Ishikawa tumors had the lowest microvessel density. All tumor models in mice treated with GSK2256098 exhibit less proliferation via Ki67 than control. Ishikawa tumors have the lowest Ki67 expression in response to therapy. Ishikawa tumors have higher apoptotic indices than Hec1A tumors after treatment with GSK2256098. Significant rates of apoptosis are seen in all models that had been treated with combination GSK2256098 and Paclitaxel |
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