MK-8776

Here, we have analysed the response of head and neck squamous cell carcinoma (HNSCC) cell lines, spheroids and patient-derived organoids to X-rays and proton beam therapy (PBT) in the presence of either a Chk1 (MK-8776) or a Wee1 (MK-1775) inhibitor. We demonstrate that inhibitors of Chk1 or Wee1 can significantly enhance the radiosensitivity of both 2D and 3D models of HNSCC to X-rays and PBT (performed at both low and high ionisation densities), and that this effect is caused through abrogation of the G2/M checkpoint causing the persistence of DSBs. Our results therefore suggest that targeting Chk1 and Wee1 kinases in combination with X-rays and PBT could represent a promising therapeutic avenue to enhance the clinical efficacy of HNSCC treatment.

No changes were observed in corresponding liver tissues using Ki-67 and pCHK staining, which indicates the absence of metastases and a hepatotoxic effect. Thus, our results indicate that the dual inhibition of PARP and CHK1 may prove to be a promising therapeutic approach in the treatment of primary HCC as well as OC tumors without the risk of liver metastases, especially in patients with olaparib-resistant tumor profiles.

Olaparib-resistant xenografts were treated with olaparib, ATR inhibitor (ATRi, ceralasertib), CHK1 inhibitor (CHK1i, MK-8776) or their combinations. Our collective findings indicate that ATR/CHK1 pathway inhibition restores the olaparib efficacy in resistant BRCA1/2MUT high-grade serous OC, highlighting promising approach for olaparib rechallenge of non-responsive patients. Uncovered mechanisms might improve our understanding of acquisition and overcoming resistance to olaparib in ovarian cancer.

Loss of FAM110C expression sensitizes PDAC cells to VE-822 (an ATR inhibitor) and MK-8776 (a CHK1 inhibitor). FAM110C methylation is a potential diagnostic and prognostic marker in PDAC, and its epigenetic silencing sensitizes PDAC cells to ATR/CHK1 inhibitors.

HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier. Collectively, our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H, providing a potential therapeutic approach for the treatment of TNBC.

Through in silico screening of 2183 drug targets and 1646 compounds, we identified two targets (RRM2 and OPRD1) and eight agents (AZ960, carmustine, lasalocid, SGI-1776, AZD8055_1059, BPD.00008900_1998, MK.8776_2046, and XAV939_1268) with potential therapeutic implications for high-MRPScore patients. Indeed, a high MRPScore profile appears to elevate the risk of tumor progression and mortality, potentially through its influence on immune regulation. This suggests that the MRPS-related risk model holds promise as a prognostic predictor and may offer novel insights into personalized therapeutic strategies.

Here we newly demonstrate that pharmacological inhibition of Chk1 using potent and selective inhibitor SCH900776, currently profiled in phase II clinical trials, significantly enhances cytotoxic effects of the combination of platinum-based drugs (cisplatin or LA-12) and TRAIL (tumor necrosis factor-related apoptosis inducing ligand) in human prostate cancer cells. The triple drug combination-induced cytotoxicity was partially enhanced by siRNA-mediated Mcl-1 silencing. Our findings suggest that targeting Chk1 may be used as an efficient strategy for sensitization of prostate cancer cells to killing action of platinum-based chemotherapeutic drugs and TRAIL.

Importantly, targeted inhibition of the check-point inhibitor CHK1 with MK-8776 effectively caused death of p21-high T47D cells, thus establishing a new vulnerability of BYL719-resistant breast cancer cells. Together, our integrated studies uncover hidden molecular mediators causing resistance to PI3Kα inhibition and provide a framework to prioritize combination therapies for PI3K-mutant breast cancer.

Antitumor activity of olaparib alone or combined with an ATR inhibitor (ATRi, ceralasertib) or CHK1 inhibitor (CHK1i, MK-8776) was evaluated in OC cell lines sensitive (PEO1, PEO4) and resistant (PEO1-OR) to olaparib. Overall, the addition of ATRi or CHK1i to olaparib effectively overcomes resistance to PARPi exerting anti-proliferative effect in BRCA2 olaparib-resistant OC cells and alters expression of DDR-related proteins. These new molecular insights into cellular response to olaparib combined with ATR/CHK1 inhibitors might help improve targeted therapies for olaparib-resistant OC.

We classified 3 molecular subtypes for HNSC patients and established an ARS prognostic model, which offered a prospective direction for prognosis in HNSC.

The current treatment approach for APL involves differentiation therapy using all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Overall, the ability of MK-8776 to induce PML-RARα degradation and stimulate differentiation of immature APL cancer cells into more mature forms recapitulates the concept of differentiation therapy. Considering the in vivo tolerability of MK-8776, it will be relevant to evaluate its potential clinical benefit in APL patients resistant to standard ATRA/ATO therapy, as well as in patients with other forms of acute leukemias.

Different TNBC cell lines were treated with AURKA inhibitor (AURKAi, MLN8237) and CHK1i (CHK1i, MK8776). Additionally, dual inhibition of AURKA and CHK1 synergistically enhanced radiosensitivity in MDA-MB-231 xenografts. Moreover, we detected that both CHEK1 and AURKA were overexpressed in TNBC patients and negatively correlated with patients' survival Our findings suggested that AURKAi in combination with CHK1i enhanced TNBC radiosensitivity in preclinical models, potentially providing a novel strategy of precision treatment for patients with TNBC.