Browsing by Subject "Targeted therapy"
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Item Open Access The AKT inhibitor MK-2206 is cytotoxic in hepatocarcinoma cells displaying hyperphosphorylated AKT-1 and synergizes with conventional chemotherapy(Impact Group, 2013) Simioni, C.; Martelli, A. M.; Cani, A.; Cetin-Atalay, R.; McCubrey, J. A.; Capitani, S.; Neri, L. M.Hepatocellular carcinoma (HCC) is one of the most common potentially lethal human malignancies worldwide. Advanced or recurrent HCC is frequently resistant to conventional chemotherapeutic agents and radiation. Therefore, targeted agents with tolerable toxicity are mandatory to improve HCC therapy and prognosis. In this neoplasia, the PI3K/Akt signaling network has been frequently shown to be aberrantly up-regulated. To evaluate whether Akt could represent a target for treatment of HCC, we studied the effects of the allosteric Akt inhibitor, MK-2206, on a panel of HCC cell lines characterized by different levels of Akt-1 activation. The inhibitor decreased cell viability and induced cell cycle arrest in the G0/G1 phase of the cell cycle, with a higher efficacy in cells with hyperphosphorylated Akt-1. Moreover, MK-2206 induced apoptosis, as documented by Annexin V labeling, and also caused autophagy, as evidenced by increased levels of the autophagy marker LC3A/B. Autophagy was shown to be a protective mechanism against MK-2206 cytotoxicity. MK-2206 down-regulated, in a concentration-dependent manner, the phosphorylation levels of Akt-1 and its downstream targets, GSK3 α/β and FOXO3A. MK-2206 synergized with doxorubicin, a chemotherapeutic drug widely used for HCC treatment. Our findings suggest that the use of Akt inhibitors, either alone or in combination with doxorubicin, may be considered as an attractive therapeutic regimen for the treatment of HCC.Item Open Access BO-264: Highly potent TACC3 inhibitor as a novel anticancer drug candidate(2021-01) Akbulut, ÖzgeBreast cancer has been consistently ranked to be the most common cancer and the second leading cause of cancer-related death in women worldwide for many years. Despite better understanding of tumor biology and the availability of plethora of anti-cancer therapeutics utilizing different strategies, complete response and/or long-term survival is achieved in only a small fraction of patients with aggressive disease. Since microtubule re-organization is an important step during cell division, drugs that interfere with this process have been a major focus of cancer research. Although anti-microtubule agents are widely used in clinic, cytotoxicity to non-tumorigenic cells and drug resistance are still the main obstacles. Therefore, development of alternative target molecules that selectively and efficiently target cancer cells, but restore normal cells are needed. Transforming acidic coiled-coil containing protein 3 (TACC3) is an important TACC family member, having both mitosis-related roles e.g. regulation of centrosomes and microtubule stability and interphase-related roles e.g. regulation of gene expression and cell migration. Being overexpressed in a broad spectrum of cancers and correlation of its expression with disease progression make TACC3 a highly attractive therapeutic target. Although the oncogenic role of TACC3 has been established albeit mostly in in vitro settings, there is currently no TACC3 inhibitor being tested in clinics. Therefore, by combining rational drug design and screening, we aimed to identify and characterize a novel TACC3 inhibitor hit molecule with high potency and minimum toxicity in in vitro and in vivo systems that is amenable for future drug development. BO-264 was identified as a novel inhibitor targeting TACC3 by direct binding validated by using several biochemical methods, including drug affinity responsive target stability, cellular thermal shift assay, and isothermal titration calorimetry. Compared to two other available TACC3 inhibitors, it showed superior inhibition of mitotic progression and cell viability, especially in aggressive basal and HER2+ breast cancer cell lines. Notably, BO-264 had remarkable cytotoxicity effect on several cancer cell lines in NCI-60 human cancer cell line panel (≥ 90% have less than 1 µM GI50 value) and inhibited the proliferation of FGFR3-TACC3 fusion protein-harboring cells, an oncogenic driver in several malignancies. Importantly, BO-264 did not cause any cytotoxicity to non-cancerous cell lines. Noteworthy, its oral administration significantly suppressed tumor growth in both breast and colon cancer syngeneic and xenograft models, and prolonged survival with no major toxicity. Finally, TACC3 expression level has been identified as a strong independent prognostic factor in breast cancer. Collectively, our preclinical findings suggest that BO-264 is a potent and non-toxic anti-cancer agent targeting TACC3 in breast and colon cancer and can be developed further to obtain better drug-like properties.Item Open Access Identification of actionable drug targets in triple-negative breast cancer(2022-09) Tokat, Ünal MetinTriple-negative breast cancer (TNBC) is the most aggressive subtype of the breast cancer, representing 15-20% of all cases. Due to a lack of clinically available/approved targeted therapies, TNBC patients are still in desperate need of chemotherapy. Although TNBC patients initially have relatively high rates of response to chemotherapy, de novo and acquired resistance constitute a major problem, leading to worsened patient outcomes. Considering the initial high response rates and broad availability and affordability of the chemotherapy agents, it is of great utility to explore the molecular mechanisms driving or contributing to de novo and acquired chemoresistance. Therefore, I developed 9 acquired resistant cell lines and 3 acquired resistant xenografts and harnessed 4 de novo TNBC chemoresistance models to identify the resistance-driving factors for each chemotherapy class/agent. Following characterization of these models in comparison to their parental counterparts at protein level, I determined few candidate proteins involved in chemoresistance. By combining experimental and bioinformatic approaches, I showed translational potential of i) p38 and JNK MAPK, and PI3K/AKT inhibitors, and ER stress inducers in de novo and acquired resistance against antimetabolite chemotherapy agents such as gemcitabine and fluorouracil; ii) dual EGFR/HER2, EGFR, SRC and CDK1 inhibitors against an antimicrotubule agent, paclitaxel; iii) FAK and dual PI3K/mTOR inhibitors against an alkylating chemotherapy agent, cisplatin, and iv) FAK, SRC and PI3K/AKT inhibitors against a topoisomerase II inhibitor, doxorubicin. I further observed that molecular underpinnings of de novo and acquired resistance were largely overlapping albeit not the same. We have also investigated cross chemotherapy resistance patterns in each acquired cell line model, which can guide second- or third-line treatment selection. As a result, I present a rational approach to exploit chemotherapy-small molecule inhibitor combinations for previously untreated or treated TNBC patients. In other words, using low-dose chemotherapy and targeted therapy combinations we provide promising preclinical in vitro data for future in vivo testing.