Project description:In the present study, we examined a hypothesis that dichloroacetate, a metabolic inhibitor, might efficiently potentiate the cytotoxic effect of salinomycin, an antibiotic ionophore, on two human colorectal cancer derived cell lines DLD-1 and HCT116. First, we performed a series of dose response experiments in the 2D cell culture by applying mono- and combination therapy and by using the Chou-Talalay method found that salinomycin in combination with dichloroacetate acted synergistically in both cell lines. Secondly, in order to recapitulate the in vivo tumor architecture, we tested various doses of these compounds, alone and in combination, in the 3D multicellular spheroid culture. The effect of combination of dichloracetate and salinomycin on multicellular spheroid size was stronger than the sum of both monotherapies, particularly in HCT116 cells. Further, we demonstrate that the synergistic effect of compounds may be related to the inhibitory effect of dichloroacetate on multidrug resistance proteins, and in contrast, it is not related to dichloroacetate-induced reduction of intracellular pH. Our findings indicate that the combination therapy of salinomycin and dichloroacetate could be an effective option for colorectal cancer treatment and provide the first mechanistic explanation of the synergistic action of these compounds.
Project description:Cancer stem cells (CSCs) are the subpopulation of cells within a tumor that can self-renew, differentiate into multiple lineages, and drive tumor growth. Here we describe a two-pronged approach for the identification and characterization of CSCs from colorectal cancer cell lines, using a Matrigel-based differentiation assay, and cell surface markers CD44 and CD24. About 20 to 30% of cells from the SW1222 cell line form megacolonies in Matrigel that have complex 3D structures resembling colonic crypts. The megacolonies' capacity to self-renew in vitro is direct evidence that they contain the CSCs. Furthermore, just 200 cells from SW1222 megacolonies initiate tumors in NOD/SCID mice. We also showed that CD44(+)CD24(+) cells enriched for colorectal CSCs in the HT29 and SW1222 cell lines, which can self-renew and reform all four CD44/CD24 subpopulations, are the most clonogenic in vitro and can initiate tumors in vivo. A single SW1222 CD44(+)CD24(+) CSC, when grown in Matrigel, can form large megacolonies that differentiate into enterocyte, enteroendocrine, and goblet cell lineages. The HCT116 line does not differentiate or express CDX1, nor does it contain subpopulations of cells with greater tumor-forming capacity, suggesting that HCT116 contains mainly CSCs. However, forced expression of CDX1 in HCT116 leads to reduced clonogenicity and production of differentiating crypt-containing colonies, which can explain the selection for reduced CDX1 expression in many colorectal cancers. In summary, colorectal cancer cell lines contain subpopulations of CSCs, characterized by their cell surface markers and colony morphology, which can self-renew and differentiate into multiple lineages.
Project description:The methanol extracts of the aerial part of four ethnomedicinal plants of Mediterranean region, two non-seed vascular plants, Equisetum hyemale L. and Phyllitis scolopendrium (L.) Newman, and two Spermatophyta, Juniperus communis L. (J. communis) and Cotinus coggygria Scop. (C. coggygria), were screened against four human cells lines (A549, MCF7, TK6 and U937). Only the extracts of J. communis and C. coggygria showed marked cytotoxic effects, affecting both cell morphology and growth. A dose-dependent effect of these two extracts was also observed on the cell cycle distribution. Incubation of all the cell lines in a medium containing J. communis extract determined a remarkable accumulation of cells in the G2/M phase, whereas the C. coggygria extract induced a significant increase in the percentage of G1 cells. The novelty of our findings stands on the observation that the two extracts, consistently, elicited coherent effects on the cell cycle in four cell lines, independently from their phenotype, as two of them have epithelial origin and grow adherent and two are lymphoblastoid and grow in suspension. Even the expression profiles of several proteins regulating cell cycle progression and cell death were affected by both extracts. LC-MS investigation of methanol extract of C. coggygria led to the identification of twelve flavonoids (compounds 1-11, 19) and eight polyphenols derivatives (12-18, 20), while in J. communis extract, eight flavonoids (21-28), a α-ionone glycoside (29) and a lignin (30) were found. Although many of these compounds have interesting individual biological activities, their natural blends seem to exert specific effects on the proliferation of cell lines either growing adherent or in suspension, suggesting potential use in fighting cancer.
Project description:Colorectal cancer (CRC) represents the third most frequently diagnosed malignancy worldwide and is the second most common cause of tumor-associated mortalities in Korea. Due to the disease's aggressive behavior, the 5-year survival rate for CRC patients remains unpromising. Well-characterized cell lines have been used as a biological model for studying the biology of cancer and developing novel therapeutics. To assist in vitro studies, 18 CRC cell lines (SNU-1566, SNU-1983, SNU-2172, SNU-2297, SNU-2303, SNU-2353B, SNU-2359, SNU-2373B, SNU-2407, SNU-2423, SNU-2431, SNU-2465, SNU-2493, SNU-2536C, SNU-2621B, SNU-NCC-61, SNU-NCC-376, and SNU-NCC-377) derived from Korean patients were established and characterized in the present study. General characteristics of each cell line including doubling time, in vitro morphology, mutational profiles, and protein expressions of CRC-related genes were described. Whole exome sequencing was performed on each cell line to configure mutational profiles. Single nucleotide variation, frame shift, in-frame deletions and insertions, start codon deletion, and splice stop codon mutation of various genes were found and classified based on their pathogenicity reports. In addition, cell viability was assayed to measure their sensitivities to 24 anti-cancer drugs including anti-metabolites, kinase inhibitors, histone deacetylase inhibitors, alkylating inhibitors, and topoisomerase inhibitors, all widely used for various cancers. On testing, five CRC cell lines showed MSI, of which MLH1 or MSH6 gene was mutated. These newly established CRC cell lines can be used to investigate biological characteristics of CRC, particularly for investigating gene alterations associated with CRC.
Project description:In defining the genetic profiles in cancer, cytogenetically aberrant cell lines derived from primary tumors are important tools for the study of carcinogenesis. Here, we present the results of a comprehensive investigation of 15 established colorectal cancer cell lines using spectral karyotyping (SKY), fluorescence in situ hybridization, and comparative genomic hybridization (CGH). Detailed karyotypic analysis by SKY on five of the lines (P53HCT116, T84, NCI-H508, NCI-H716, and SK-CO-1) is described here for the first time. The five lines with karyotypes in the diploid range and that are characterized by defects in DNA mismatch repair had a mean of 4.8 chromosomal abnormalities per line, whereas the 10 aneuploid lines exhibited complex karyotypes and a mean of 30 chromosomal abnormalities. Of the 150 clonal translocations, only eight were balanced and none were recurrent among the lines. We also reviewed the karyotypes of 345 cases of adenocarcinoma of the large intestine listed in the Mitelman Database of Chromosome Aberrations in Cancer. The types of abnormalities observed in the cell lines reflected those seen in primary tumors: there were no recurrent translocations in either tumors or cell lines; isochromosomes were the most common recurrent abnormalities; and breakpoints occurred most frequently at the centromeric/pericentromeric and telomere regions. Of the genomic imbalances detected by array CGH, 87% correlated with chromosome aberrations observed in the SKY studies. The fact that chromosome abnormalities predominantly result in copy number changes rather than specific chromosome or gene fusions suggests that this may be the major mechanism leading to carcinogenesis in colorectal cancer.
Project description:In colorectal cancer chemotherapy, the current standard of care includes combination therapy with 5-fluorouracil (5-FU) and leucovorin (LV). However, the factors that determine the LV-mediated enhancement of 5-FU antitumor activity are not fully understood. Therefore, we investigated the roles of thymidine synthase (TYMS), folate receptor 1 (FOLR1), dihydrofolate reductase (DHFR), phosphoribosylglycinamide formyltransferase (GART), methylenetetrahydrofolate dehydrogenase (MTHFD1), and methylenetetrahydrofolate reductase (MTHFR) in LV-mediated enhancement of 5-fluoro-2'-deoxyuridine (FdUrd) cytotoxicity in vitro as a model of 5-FU antitumor activity. These genes were downregulated in DLD-1 and HCT116 human colorectal cancer cells by using small-interfering RNA. Reduced expression of TYMS mRNA significantly increased FdUrd cytotoxicity by 100- and 8.3-fold in DLD-1 and HCT116 cells, respectively. In contrast, reducing the expression of FOLR1, DHFR, GART, MTHFD1, and MTHFR decreased FdUrd cytotoxicity by 2.13- to 12.91-fold in DLD-1 cells and by 3.52- to 10.36-fold in HCT116 cells. These results demonstrate that folate metabolism is important for the efficacy of FdUrd. Overall, the results indicate that it is important to clarify the relationship between folate metabolism-related molecules and 5-FU treatment in order to improve predictions of the effectiveness of 5-FU and LV combination therapy.
Project description:BackgroundPeroxisome proliferator-activated receptor gamma (PPARG) is a member of the nuclear receptor family. It is involved in the regulation of adipogenesis, lipid metabolism, insulin sensitivity, vascular homeostasis and inflammation. In addition, PPARG agonists, known as thiazolidinediones, are well established in the treatment of type 2 diabetes mellitus. PPARGs role in cancer is a matter of debate, as pro- and anti-tumour properties have been described in various tumour entities. Currently, the specific role of PPARG in patients with colorectal cancer (CRC) is not fully understood.Material and methodsThe prognostic impact of PPARG expression was investigated by immunohistochemistry in a case-control study using a matched pair selection of CRC tumours (n = 246) with either distant metastases to the liver (n = 82), lung (n = 82) or without distant metastases (n = 82). Its effect on proliferation as well as the sensitivity to the chemotherapeutic drug 5-fluorouracil (5-FU) was examined after activation, inhibition, and transient gene knockdown of PPARG in the CRC cell lines SW403 and HT29.ResultsHigh PPARG expression was significantly associated with pulmonary metastasis (p = 0.019). Patients without distant metastases had a significantly longer overall survival with low PPARG expression in their tumours compared to patients with high PPARG expression (p = 0.045). In the pulmonary metastasis cohort instead, a trend towards longer survival was observed for patients with high PPARG expression in their tumour (p = 0.059). Activation of PPARG by pioglitazone and rosiglitazone resulted in a significant dose-dependent increase in proliferation of CRC cell lines. Inhibition of PPARG by its specific inhibitor GW9662 and siRNA-mediated knockdown of PPARG significantly decreased proliferation. Activating PPARG significantly increased the CRC cell lines sensitivity to 5-FU while its inhibition decreased it.ConclusionThe prognostic effect of PPARG expression depends on the metastasis localization in advanced CRC patients. Activation of PPARG increased malignancy associated traits such as proliferation in CRC cell lines but also increases sensitivity towards the chemotherapeutic agent 5-FU. Based on this finding, a combination therapy of PPARG agonists and 5-FU-based chemotherapy constitutes a promising strategy which should be further investigated.
Project description:Cell cycle progression and DNA synthesis are essential steps in cancer cell growth. Thymidylate synthase (TS) is a therapeutic target for 5FU. We tested the hypothesis that HSP90 transcriptional and functional inhibition can inhibit cell cycle progression, downregulate TS levels and sensitize colorectal cancer (CRC) cell lines to the effects of 5FU. Treatment with ganetespib (50 nM) for 24 hours inhibited cyclin D1 and pRb at the transcriptional and translational levels and induced p21, leading to G0/G1 cell cycle arrest in both CRC cell lines (HCT-116 and HT-29). This was associated with downregulation of E2F1 and its target gene TS. In addition, ganetespib inhibited PI3K/Akt and ERK signalling pathways. Similar effects were observed with HSP90 knockdown in both cell lines. Ganetespib sensitized CRC cell lines to the effects of oxaliplatin and 5FU. Similar effects were also observed in tumors from animals treated with ganetespib, oxaliplatin and 5FU. In this study, we present in vitro and animal data supporting that the targeting of HSP90 decreases CRC cell survival and proliferation. Ganetespib sensitizes CRC cell lines to the effects of 5FU-based chemotherapy. Combining HSP90 inhibitors with chemotherapy is a rational approach for future drug development in CRC.
Project description:Colorectal cancer has a relatively low sensitivity to paclitaxel. The purpose of this study was to investigate the role of connexin 43 (Cx43), which is a structural component of gap junctional communication (GJC), in paclitaxel cytotoxicity in colorectal cancer cells. Three colorectal cancer cell lines (HCT106, HCT116 and LoVo) were transfected with Cx43 and used to examine paclitaxel cytotoxicity. A western blot assay was used to confirm Cx43 expression in transfected cell lines as well as the expression of several proteins that are associated with paclitaxel cytotoxicity. A parachute dye-coupling assay was used to measure GJC function. An MTT assay was used to analyze the viability of paclitaxel-treated cells. Cx43 expression level and GJC function were significantly upregulated by the transfection (P<0.05). The viability of transfected cells was significantly inhibited compared with that of untransfected cells when treated with paclitaxel (20 or 80 nM) at high culture density but not at low culture density (P<0.05). Cx43 transfection significantly increased the mitotic arrest, tubulin polymerization and apoptosis effects of paclitaxel (P<0.05). It was also found that paclitaxel had an inhibitory effect on GJC function after 12 h of treatment in LoVo cells (P<0.05). These results indicate that Cx43 may serve as a target of paclitaxel chemotherapy for colorectal cancer.