Chemotherapy In Various Tumors Research Articles

Depolymerization of tubulin as the main molecular mechanism of the cytotoxic and antitumor activity of pyrrole-containing heterocyclic compounds

Introduction. Microtubules are highly dynamic polymers of α, β-tubulin dimers involves in a broad spectrum of the processes, such as intracellular transport and cell proliferation. This makes them an attractive molecular target for anti-cancer therapies. Substances that affect the dynamic state of tubulin microtubules are known as the mitotic poisons that are effectiveand widely used in the chemotherapy of various tumors. Mitotic poisons are able to interfere with polymerization (stabilization) or depolymerization of tubulin, which in turn leads to the arrest of cells in the M-phase (named as a mitotic catastrophe) and their subsequent death via activation of apoptotic mechanisms. However, the effectiveness of MP-based therapies is gradually decreasing over the time due to development of multiple drug resistance mechanisms in cancer cells. Thus, development of novel compounds selectively targeting tubulin and effectively overcoming multiple drugresistance phenotype in cancer is an urgent need in current oncology. Aim. To examine the cytotoxic and antitumor activities of several pyrrole-containing heterocyclic compounds (EPC-91, EPC-92 and PCA-93) against cancer cell lines with epithelial and mesenchymal origin, including those with multiple drug resistance phenotype. Materials and methods. Studies were performed on parental human cancer cell lines – triple-negative breast cancer HCC1806, gastrointestinal stromal tumor GIST T-1, osteosarcoma SaOS-2, – sensitive to chemotherapy (paclitaxel, doxorubicin) and their resistant sublines (HCC1806 Tx-R, GIST T-1 Tx-R, SaOS-2 Dox-R), as well as on murine colorectal adenocarcinoma cell line Colon-26, exhibiting primary resistance to the aforementioned chemotherapeutic agents. Results. The cytotoxic activities of EPC-91 and PCA-93 were due to their abilities to depolymerize tubulin. The results of immunofluorescence microscopy and Western blotting indicated that the compounds disrupt assembly of tubulin microtubules and prevent polymerization of α-tubulin in cancer cells. Inhibition of tubulin polymerizations led to significant increasein number of round-shaped and phospho-histone 3 (e. g. mitotic) cells, followed by their death through apoptosis. PCA-93 also exhibited potent anti-tumor effect against Colon-26 cells due to its anti-proliferative and proapoptotic activities. Conclusion. The data shown here illustrates potent cytotoxic activities of EPC-91 and PCA-93 against multiple cancer cell lines in vitro including those with multiple drug resistance phenotype. Similarly, PCA-93 was found to be highly effective against Colon-26 cell in vivo, thereby illustrating the attractive platform for the development of novel pyrrole-based agents exhibiting potent anti-tumor activities.

PI3K/AKT signaling pathway as a critical regulator of Cisplatin response in tumor cells

Chemotherapy is one of the main therapeutic modalities for cancer patients. Cisplatin (CDDP) as one of the first line drugs is of great importance in the chemotherapy of various tumors. However, a significant percentage of cancer patients are resistant toward CDDP treatment. Due to the CDDP side effects on normal tissues, therefore, the diagnosis of CDDP resistance is required to suggest the most efficient therapeutic strategies in cancer patients. Several molecular mechanisms and signaling pathways are associated with CDDP response. The PI3K/AKT signaling pathway has a pivotal role in transmission of extracellular signals into the cells to regulate various pathophysiological processes such as cell proliferation, migration, and drug resistance. In the present review, we summarized all of the studies which have been reported the role of PI3K/AKT pathway in regulation of CDDP response. It was shown that the PI3K/AKT pathway is mainly involved in CDDP response in lung, ovarian, and gastrointestinal cancers. It was also observed that the non-coding RNAs have a key role in CDDP response by regulation of PI3K/AKT pathway. This review paves the way of suggesting a PI3K/AKT-related panel marker for the prediction of CDDP response in different cancer patients.

Abstract A36: Developing a novel treatment for advanced ovarian cancer by targeting the c-Met pathway

Abstract Approximately one-third of epithelial ovarian tumors exhibit higher levels of c-Met, a receptor tyrosine kinase, activated by Hepatocyte Growth Factor (HGF). c-Met plays an important role in the growth and metastasis of tumor cells. Increased c-Met expression is associated with decreased survival and resistance to chemotherapy in various tumors. More recently, our team identified c-Met overexpression as a mechanism of resistance to neoadjuvant chemotherapy (NACT) in ovarian cancer (OC). The c-Met pathway has been explored as a therapeutic target in various solid tumors, and antibodies targeting c-Met have been proposed as novel anticancer agents. This project aims to investigate the effectiveness of a c-Met monoclonal antibody-drug conjugate (c-Met ADC) in OC models. Here we show that the anti-c-Met antibody alone effectively diminishes c-Met signaling (phosphorylation of c-Met and downstream Akt) but does not inhibit OC cell proliferation. In contrast, the c-Met ADC significantly decreases viability and induces apoptosis in c-Met-expressing OC cells. To validate c-Met expression as a predictor of resistance to NACT in OC, we analyzed c-Met expression in matched pre- and post-treatment samples collected from OC patients undergoing treatment with NACT and in a tissue microarray containing 20 ovarian tumors post-NACT. Detectable c-Met was recorded in ~50% of post-NACT specimens. We evaluated the in vitro antitumor activity of c-Met-ADC on the primary cells isolated from patients, before and after NACT, to assess tumor cell sensitivity to c-Met ADC. The results from these studies support the development of c-Met-ADC as a novel treatment for OC. Citation Format: Anusha Chaparala, Wendy M. Swetzig, Anna E. Strohl, Jian-Jun Wei, Daniela Matei, Shohreh Shahabi. Developing a novel treatment for advanced ovarian cancer by targeting the c-Met pathway [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A36.

Targeting lung cancer stem cells using combination of Tel and Docetaxel liposomes in 3D cultures and tumor xenografts

Cancer stem cells (CSCs) accounts for recurrence and resistance to chemotherapy in various tumors. Efficacy of chemotherapeutic drugs is limited by tumor stromal barriers, which hinder their penetration into deep tumor sites. We have earlier shown telmisartan (Tel) pretreatment prior to Docetaxel (DTX) administration enhances anti-cancer effects in non-small cell lung cancer (NSCLC). Herein, we demonstrated for the first time the efficacy of Docetaxel liposomes (DTXPL) in combination with Tel in 3D cultures of H460 cells by using polysaccharide-based hydrogels (TheWell Biosciences) and also in xenograft model of DTX resistant H460 derived CD133+ lung tumors. DTXPL and Tel combination showed enhanced cytotoxicity in H460 WT 3D cultures by two folds. In H460 3D cultures, Tel pretreatment showed increased liposomal uptake. DTXPL and Tel combination treated tumors showed reduction in tumor volume (p < .001), increased apoptosis and downregulation of CSC markers (p < .01) in H460 WT and DTX resistant CD133+ xenograft models.

Abstract 1663: Selective CDK8 inhibitor SEL120-34A alters expression of interferon-related DNA damage resistance signature genes in colorectal cancer

Abstract CDK8 (cyclin-dependent kinase 8) is a kinase component of a multi - protein Mediator complex, involved in transcription control. Several studies indicated that high overexpression and activity of CDK8 could be a driver of malignant progression in colorectal cancer (CRC). Herewith we present molecular insights into mechanism of action of SEL120-34A - a selective small molecule inhibitor of CDK8 kinase. Biochemical and binding studies indicated that SEL120-34A selectively binds and inhibits enzymatic activity of CDK8 in the low nM range. Recently CDK8 has been described as a regulator of STAT1 activity in NK cells where by phosphorylating STAT1 serine 727 (Ser727) influences a possible immunoescape mechanism in various cancers. Consistently, SEL120-34A and other recently reported selective CDK8 inhibitors could repress phosphorylation of STAT1 at a Ser727 at low nM concentrations in cancer cells without any significant changes on tyrosine sites directly regulated by JAK kinases. SEL120-34A inhibited expression of several STAT1 dependent genes in CRC cell lines, stimulated by various cytokines and growth factors. These results were further corroborated with specific CDK8 siRNA knockdown experiments and chromatin immunoprecipitation studies showing CDK8 occupancy on promoters of SEL120-34A regulated genes. In order to better characterize in vivo mechanism of action, mice bearing HCT116 and Colo205 xenograft tumors were treated with SEL120-34A and gene expression changes were measured with microarrays in excised tumors. In animals treated with the CDK8 inhibitor a dose dependent repression of STAT1 Ser727 was observed. The functional analyses of significantly (adj. p. value &amp;lt; 0.05) altered genes with Gene Ontology revealed that those with reduced expression belong to interferon I pathway and type I interferon-mediated signaling pathway terms. This subset of STAT regulated genes was further characterized as an interferon-related DNA damage resistance signature (IRDS) - a prosurvival pathway which correlated strongly with resistance to radiation and chemotherapy in various tumors. Consistently, SEL120-34A has shown very potent cytotoxic synergy with standard of care drugs in CRC, particularly in cells stimulated with interferons. Taken together, for the first time we have shown that selective CDK8 inhibitors are potent regulators of STAT related - IRDS signaling pathway in vitro and in vivo. In addition to previously reported stand-alone efficacy of CDK8 inhibitors in vivo, we provide also a combination treatment rationale for CRC. Citation Format: Tomasz Rzymski, Michał Mikula, Małgorzata Szajewska-Skuta, Eliza Zyłkiewicz, Łukasz Sapała, Izabela Dolata, Agata Kitlińska, Krzysztof Goryca, Aleksandra Grochowska, Aleksandra Cabaj, Agnieszka Dreas, Katarzyna Kucwaj, Artur Białas, Adam Radzimierski, Aniela Gołas, Renata Windak, Jerzy Ostrowski, Krzysztof Brzózka. Selective CDK8 inhibitor SEL120-34A alters expression of interferon-related DNA damage resistance signature genes in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1663. doi:10.1158/1538-7445.AM2015-1663

2-Deoxy-D-Ribose, a Downstream Mediator of Thymidine Phosphorylase, Regulates Tumor Angiogenesis and Progression

Angiogenesis plays an important role in tumor metastasis and progression, and thus inhibiting angiogenesis is a promising strategy for treatment of cancer. However, tumor-associated angiogenesis is influenced by various angiogenic factors in the tumor microenvironment. Thymidine phosphorylase (TP, EC 2. 4. 2. 4), an enzyme involved in the reversible conversion of thymidine to thymine, is an important mediator of angiogenesis, tumorigenicity, metastasis and invasion. The angiogenic effect of TP requires the enzymatic activity of TP. TP activity is expressed at higher levels in a wide variety of solid tumors than in adjacent non-neoplastic tissue. The tumor microenvironment (hypoxia, acidosis) regulates the expression of TP, and TP expression in tumor tissue shows significant correlation with microvessel density and poor prognosis. 2-Deoxy-D-ribose (D-dRib), one of the degradation products of thymidine generated by TP activity, promotes angiogenesis and the chemotactic activity of endothelial cells and also confers resistance to hypoxia-induced apoptosis in some cancer cell lines. These findings suggest that D-dRib is a downstream mediator of TP function. 2-Deoxy-L-ribose, a stereoisomer of D-dRib, can inhibit D-dRib's anti-apoptotic effects and suppress metastasis and invasion of TP-expressing tumors in mice. Although the mechanism of action of D-dRib is still unknown, the physiological activities of D-dRib have recently been reported by several groups. We review the role of D-dRib in tumor progression and discuss inhibition of D-dRib as a promising approach for chemotherapy of various tumors.

Analysis of UbcH10 expression represents a useful tool for the diagnosis and therapy of astrocytic tumors

Previous studies suggest the expression of UbcH10 gene, that codes for a protein belonging to the ubiquitin-conjugating enzyme family, as a valid indicator of the proliferative and aggressive status of tumors of different origin. Therefore, to look for possible tools to be used as diagnostic markers in astrocytic neoplasias, we investigated UbcH10 expression in normal brain, gliosis and low-grade and high-grade astrocytic tumors by immunohistochemistry. UbcH10 expression was observed in low-grade astrocytoma and in glioblastoma. Our data indicate a clear correlation between UbcH10 expression and the histological grade of the astrocytic tumors. Moreover, the analysis of UbcH10 expression allows the differentiation between gliotic and malignant tissues. Finally, since proteasome inhibitors have recently been considered as possible drugs in the chemotherapy of various tumors, our results would suggest new perspectives for the treatment of brain malignancies based on the suppression of the UbcH10 function.

The role of thymidine phosphorylase, an angiogenic enzyme, in tumor progression

Thymidine phosphorylase (TP), an enzyme involved in pyrimidine metabolism, is identical with an angiogenic factor, platelet-derived endothelial cell growth factor (PD-ECGF). TP is overexpressed in various tumors and plays an important role in angiogenesis, tumor growth, invasion and metastasis. The enzymatic activity of TP is required for the angiogenic effect of TP. A novel, specific TP inhibitor, TPI, inhibits angiogenesis induced by overexpression of TP in KB/TP cells (human KB epidermoid carcinoma cells transfected with TP cDNA), as well as the growth and metastasis of KB/TP cells in vivo. 2-deoxy-D-ribose, the degradation product of thymidine generated by TP activity, has both angiogenic and chemotactic activity. Both 2-deoxy-D-ribose and TP inhibit a hypoxia-induced apoptotic pathway. These findings suggest that 2-deoxy-D-ribose is a downstream mediator of TP function. 2-deoxy-L-ribose, a stereoisomer of 2-deoxy-D-ribose, inhibits the promotion of angiogenesis, tumor growth and metastasis by TP. Although the mechanism of the action of 2-deoxy-D-ribose is still unknown, 2-deoxy-L-ribose may inhibit the physiological activities of 2-deoxy-D-ribose, and consequently those of TP. Inhibition of TP activity and function appears to be a promising approach for the chemotherapy of various tumors.