Anti-clastogenic activity of two structurally related pterocarpans purified from Bituminaria bituminosa in cultured human lymphocytes

Plant-derived isoflavones are currently receiving much attention because of their phyto-estrogenic, antioxidant, anti-mutagenic, and anti-tumor activities. In this study we have evaluated the clastogenic and anti-clastogenic activities in human lymphocytes of two structurally related pterocarpans, iso-flavonoid derivatives, termed erybraedin C and bitucarpin A, recently purified from Bituminaria bituminosa and chemically characterized. Mitomycin C (MMC) and the radio-mimetic bleomycin (BL) were used as reference clastogens. The end point studied was micronucleus formation. The results obtained in this study indicate that erybraedin C and bitucarpin A, when assayed alone, do not affect either the mitotic index or the cell-proliferation index of human lymphocytes. Interestingly, both compounds appear to be non-clastogenic in the range of concentrations used. In contrast, both substances seem to affect significantly the clastogenic effects induced by BL and MMC. A 1-h pre-exposition of the cell culture to erybraedin C was necessary to display its anti-clastogenic potential against BL, whereas bitucarpin A was inactive in this respect, with a structure-activity relationship. In contrast, the clastogenic activity of MMC was significantly reduced by both erybraedin C and bitucarpin A, using either a pre-incubation schedule or simultaneous treatment. These results suggest that the protective effects displayed by the two anti-clastogenic compounds against MMC could be due to the induction or inhibition of cellular reductive metabolic enzymes.     

Glycine-extended gastrin exerts growth-promoting effects on human colon cancer cells.

BACKGROUND: Since human colon cancers often contain significant quantities of progastrin-processing intermediates, we sought to explore the possibility that the biosynthetic precursor of fully processed amidated gastrin, glycine-extended gastrin, may exert trophic effects on human colonic cancer cells. MATERIALS AND METHODS: Binding of radiolabeled glycine-extended and amidated gastrins was assessed on five human cancer cell lines: LoVo, HT 29, HCT 116, Colo 320DM, and T 84. Trophic actions of the peptides were assessed by increases in [3H]thymidine incorporation and cell number. Gastrin expression was determined by northern blot and radioimmunoassay. RESULTS: Amidated gastrin did not bind to or stimulate the growth of any of the five cell lines. In contrast, saturable binding of radiolabeled glycine-extended gastrin was seen on LoVo and HT 29 cells that was not inhibited by amidated gastrin (10(-6) M) nor by a gastrin/CCKB receptor antagonist (PD 134308). Glycine-extended gastrin induced a dose-dependent increase in [3H]thymidine uptake in LoVo (143 +/- 8% versus control at 10(-10) M) and HT 29 (151 +/- 11% versus control at 10(-10) M) cells that was not inhibited by PD 134308 or by a mitogen-activated protein (MAP) or ERK kinase (MEK) inhibitor (PD 98509). Glycine-extended gastrin did stimulate jun-kinase activity in LoVo and HT 29 cells. The two cell lines expressed the gastrin gene at low levels and secreted small amounts of amidated gastrin and glycine-extended gastrin into the media. CONCLUSIONS: Glycine-extended gastrin receptors are present on human colon cancer cells that mediate glycine-extended gastrin's trophic effects via a MEK-independent mechanism. This suggests that glycine-extended gastrin and its novel receptors may play a role in colon cancer cell growth.     

CEA and NCA expressed by colon carcinoma cells affect their interaction with and lysability by activated lymphocytes.

Heterogeneous lysability by interleukin-2 activated lymphocytes (LAK) and other immune effectors was observed in the human colon-carcinoma lines LoVo/Dx, LoVo/H and HT29. The tumor cells with high susceptibility to LAK (LoVo/Dx, HT29) expressed higher amounts of the adhesion molecules ICAMl, LFA3 and NCA/CEA than cells with low LAK sensitivity (LoVo/H). Monoclonal antibodies against these molecules caused a marked reduction of lysis by LAK of LoVo/Dx and HT29. A pool of these antibodies induced a nearly complete inhibition of the LAK lysis of both lines. Treatment of LoVo/Dx with differentiating agents (dimethylformamide and retinoic acid) led to a decreased expression of the adhesion molecules, including NCA, accompanied by increased resistance to LAK-mediated lysis. Moreover, the presence of CEA soluble antigen drastically inhibited the cytotoxic activity of LAK effectors against HT29 and LoVo/Dx cells, in a dose-dependent manner. These data indicate that sensitivity of colon-carcinoma cells to activated lymphocytes depends on the level of expression of adhesion molecules, including CEA and NCA. Given the role of CEA-related antigens in tumor/lymphocyte interaction, soluble CEA, frequently released by colon-carcinoma, may be involved in immunosuppressive effects induced in vivo by tumor cells.     

SOX-17 is involved in invasion and apoptosis of colorectal cancer cells through regulating miR-302b-3p expression

The prognosis of advanced colorectal cancer (CRC) is currently still very poor, which suggests that the biological mechanisms of CRC oncogenesis are not fully understood. This study was conducted to explore the regulatory effect of SOX-17 on the expression of microRNA (miR)-302b-3p, and the involvement of SOX-17 in the invasion and apoptosis of CRC cells. The expression of SOX-17 and miR-302a,b,c,d-3p in colorectal cancer and normal colon epithelial cell lines was measured by real-time polymerase chain reaction and/or western blot. The regulatory effects of SOX-17 on miR-302b-3p gene in HT29 and LoVo cells were tested using the ChiP assay. The biological activities of SOX-17 and miR-302b-3p were evaluated by invasion and apoptosis assay. Results showed that transfection of SOX-17 small interfering RNA (siSOX-17) significantly increased, whereas transfection of SOX-17 overexpression vector (oeSOX-17) significantly decreased, miR-302b expression in HT29 and LoVo cells. Cotransfection of oeSOX-17 and miR-302b-3p inhibitor (INmiR-302b) significantly blocked the effects of SOX-17 in HT29 and LoVo cells. ChIP experiments showed that SOX-17 bonded to the miR-302b-3p promoter in HT29 and LoVo cells. Transfection of oeSOX-17 and miR-302b-3p mimics (MImiR-302b) significantly decreased, whereas transfection of siSOX-17 and INmiR-302b significantly increased, the invasion of HT29 and LoVo cells. In contrast, transfection of oeSOX-17 and MImiR-302b significantly increased, while transfection of siSOX-17 and INmiR-302b significantly decreased, apoptosis in HT29 and LoVo cells. Cotransfection of oeSOX-17 and INmiR-302b significantly blocked the effects of oeSOX-17 on cell invasion and apoptosis in HT29 and LoVo cells. These results suggested that SOX-17 can bind to the promoter of miR-302b-3p gene to regulate its expression, while both SOX-17 and miR-302b regulate the invasion and apoptosis in colorectal cancer cells.     

Caco-2 and LS174T cell lines provide different models for studying mucin expression in colon cancer

To compare the differences in MUC2 and MUC5AC mRNA among four colon cancer cell lines and to identify the best in vitro models for studying mucin expression, quantitative real-time polymerase chain reaction was used to measure the expression of MUC2 and MUC5AC mRNA in Caco-2, HT29, LoVo, and LS174T cell lines. The levels of MUC2 mRNA expression in the four colon cancer cell lines ranked in order of mRNA abundance were: LS174T > LoVo > HT-29 > Caco-2. In contrast to MUC2, the abundances of MUC5AC mRNA were in the order: Caco-2 > HT-29 > LS174T > LoVo. Caco-2 (highest level of MUC5AC mRNA) and LS174T (highest level of MUC2 mRNA) were used to investigate the phenotypes. Morphologically, Caco-2 cells were larger with low electron density mucus-storing vacuoles, many cell surface microvilli, and no obvious intercellular spaces between cells, compared to LS174T cells. The proliferative and invasive capacities of LS174T cells were significantly higher than those of Caco-2 cells. Caco-2 and LS174T cells provide excellent in vitro models for studying mucin expression in colon cancer.     

microRNA-195 promotes apoptosis and suppresses tumorigenicity of human colorectal cancer cells

Deregulated microRNAs and their roles in cancer development have attracted much attention. In the present study, we analyzed the roles of miR-195 in colorectal cancer pathogenesis, as its participation in some other types of cancer has been suggested by previous reports. By comparing miR-195 expression in 81 human colorectal cancer tissues and matched non-neoplastic mucosa tissues, we found that miR-195 was downregulated in cancer tissues. And restoration of miR-195 in colorectal cancer cell lines HT29 and LoVo could reduce cell viability, promote cell apoptosis and suppress tumorigenicity. Moreover, important antiapoptotic Bcl-2 was identified to be directly targeted by miR-195, and miR-195 was further suggested to exert its proapoptotic function mainly through targeting Bcl-2 expression. Taken together, our study provides important roles of miR-195 in colorectal cancer pathogenesis and implicates its potential application in cancer therapy.     

Quinone-induced apoptosis in human colon adenocarcinoma cells via DT-diaphorase mediated bioactivation

DT-diaphorase (DTD) activity has been related to bioactivation and cytotoxicity of antitumor quinones. A pair of human colon adenocarcinoma cell lines, HT29 and BE, were used in this study to examine the role of DTD in antitumor quinone induced apoptosis. HT29 cells have elevated levels of DTD whereas BE cells lack functional DTD due to a point mutation which results in a complete lack of DTD activity. MeDZQ, a quinone that is efficiently bioactivated by DTD, induced apoptosis both in HT29 and BE cells, but with a much higher incidence in HT29, as assessed by morphological criteria and the formation of oligonucleosomal fragments of DNA. Two other quinone compounds which are also substrates for DTD, i.e. streptonigrin and mitomycin C, also preferentially induced apoptosis in HT29 cells, which could be inhibited by dicoumarol. Our data suggest that bioreductive activation of antitumor quinones by DTD results in induction of apoptosis in human colon carcinoma cells.     

Production of MUC1 and MUC2 mucins by human tumor cell lines.

A mucus secreting, clonal derivative (HT29-SB) of the human colonic adenocarcinoma cell line HT29, and the LS174T colon cancer cell line, secrete mucin into the culture medium as a viscoelastic gel. Mab BC2, which defines a peptide epitope present in the variable number of tandem repeats (VNTR) of the MUC1 core protein, reacted with this material after deglycosylation. Two high molecular weight bands were detected in TFMSA treated gel-formed mucin from HT29-SB and LS174T by western blotting (Mr 580 kDa and 420 kDa). A similar pattern of reactivity was seen with the culture supernatants from HT29-SB, the ovarian tumor cell line COLO-316, and the breast cancer cell line MCF-7. Mab CCP58 (anti-MUC2 VNTR) reacted with a 580 kDa band in gel-formed mucin produced by LS174T, but was not reactive with mucin produced by the other cell lines. The findings indicate that human colonic cell lines, in addition to breast and ovarian cell lines, may both express and secrete the MUC1 protein core, and that the LS174T cell line expresses and secretes both the MUC1 and MUC2 core proteins.     

Urolithin A induces cell cycle arrest and apoptosis by inhibiting Bcl-2, increasing p53-p21 proteins and reactive oxygen species production in colorectal cancer cells

Colorectal cancer (CRC) is the second most common gastrointestinal cancer globally. Prevention of tumor cell proliferation and metastasis is vital for prolonging patient survival. Polyphenols provide a wide range of health benefits and prevention from cancer. In the gut, urolithins are the major metabolites of polyphenols. The objective of our study was to elucidate the molecular mechanism of the anticancer effect of urolithin A (UA) on colorectal cancer cells. UA was found to inhibit the cell proliferation of CRC cell lines in a dose-dependent and time-dependent manner in HT29, SW480, and SW620 cells. Exposure to UA resulted in cell cycle arrest in a dose-dependent manner along with alteration in the expression of cell cycle–related protein. Treatment of CRC cell lines with UA resulted in the induction of apoptosis. Treatment of HT29, SW480, and SW620 with UA resulted in increased expression of the pro-apoptotic proteins, p53 and p21. Similarly, UA treatment inhibited the anti-apoptotic protein expression of Bcl-2. Moreover, exposure of UA induced cytochrome c release and caspase activation. Furthermore, UA was found to generate reactive oxygen species (ROS) production in CRC cells. These findings indicate that UA possesses anticancer potential and may be used therapeutically for the treatment of CRC.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-020-01189-8.     

Doxorubicin induces the acetylation of histone H1 in a human colon cancer cell line (LoVo/DX) selected for resistance to the drug, but not in the sensitive parental line (LoVo)

The effect of doxorubicin (DX) treatment on H1 synthesis and acetylation was studied in two human colon adenocarcinoma cell lines, sensitive (LoVo) and resistant (LoVo/DX) to this drug. Histone variants were resolved by a high resolution two-dimensional gel electrophoresis system coupled to fluorography for the detection of radioactive incorporation. The relative synthesis of H1.4 and H1.5 variants was slightly reduced by DX. This is probably related to the inhibition of DNA synthesis consequent to drug treatment. The main effect is that DX induces the acetylation of H1 isoproteins in the LoVo/DX resistant line but not in the parental line, which is 30 times more sensitive to anthracyclines. The different behavior of the two cell lines cannot be attributed to different cellular drug retention since the DX doses chosen (1.25 for LoVo and 40 micrograms/ml for LoVo/DX cells) correspond to similar intracellular drug concentrations. H1 acetylation persisted after exposure to cycloheximide in DX treated LoVo/DX cells, indicating that it is a postranslational event. The induction of H1 acetylation appears rather specific since no increase was found in 3H-acetate incorporation on the total cellular TCA-precipitable fraction. In addition DX treatment did not modify the acetylation of core histones in either LoVo or LoVo/DX cell lines.     

Expression of methionine aminopeptidase 2, N-myristoyltransferase, and N-myristoyltransferase inhibitor protein 71 in HT29

Protein myristoylation is a co-translational process, catalyzed by N-myristoyltransferase (NMT) that occurs after the initiating methionine is removed by methionine aminopeptidase (MetAP). The enzymes NMT and MetAP play a major role in the process of myristoylation of oncoproteins including the c-src family. In this study, we examined the levels of expression of MetAP2, NMT, and NMT inhibitor protein 71 (NIP71) in human colon cancer cell lines (HCCLs). We examined the influence of cell density on the expression of the above proteins in HT29 cells. Western blot analysis of MetAP2 and NMT demonstrated higher levels of protein expression in low density of HT29 while low expression in high density was observed. In addition, we observed that NIP71 and pp60(c-src) expressions were dependent on the cell density of HT29. This is the first study demonstrating the expression of MetAP2, NMT, pp60(c-src), and NIP71 in HCCLs.     

Role of Integrins and Evidence for two Distinct Mechanisms Mediating Human Colorectal Carcinoma Cell Interaction with Peritoneal Mesothelial Cells and Extracellular Matrix

Peritoneal carcinomatosis involves a series of events including tumor cell interactions with mesothelial cells and the extracellular matrix (ECM). We have studied the adhesive and invasive properties of four human colorectal carcinoma cell lines (Co115, HT29, SW480, SW620) confronted in vitro with a human mesothelial cell monolayer or with the ECM proteins collagen IV, laminin-1, fibronectin, tenascin-C and vitronectin. Quantitation was achieved following staining of tumor cells with the calcein-AM fluorescent dye. We found that all four cell lines rapidly adhered to a mesothelial cell monolayer. This adhesion event was not inhibitable by anti-integrin and anti-CD44 antibodies. Following initial attachment, the SW480 and SW620 cells invaded the mesothelial cell monolayer more aggressively than HT29 and Col 15 cells. All cell lines adhered to ECM proteins with each one exhibiting an individual adhesion pattern. Adhesion to matrix was completely integrin-dependent. When tested in an invasion assay, HT29 and Co115 cells crossed Matrigel-coated filters while SW480 and SW620 cells did not. This invasion was inhibited by anti-β1 integrin antibodies. Taken together, our results demonstrate that the initial colorectal tumor cell—mesothelial cell interaction occurs through an integrin-independent mechanism while adhesion to matrix proteins and invasion through Matrigel are integrin-dependent events. Furthermore, the different invasive capacity of SW480 and SW620 versus HT29 and Co115 cells upon interaction with a mesothelial cell monolayer or Matrigel suggests that these two invasion events may be mediated by distinct mechanisms.     

Two human colon tumor cell lines with similar nuclease sensitivities have different ethidium bromide binding characteristics

Chromatin from two human colon adenocarcinoma cell lines (HT-29 and LoVo) showed similar digestion kinetics when sensitivities to DNase I and micrococcal nuclease were examined. Chromatin conformations were probed by examining the binding of ethidium bromide. A Scatchard plot revealed that both chromatins bound the same amount of ethidium bromide per mole of DNA, but the DNA from LoVo cells was more accessible to the intercalator. The results indicate that differences in chromatin conformation are not necessarily accompanied by different nuclease sensitivities.     

(2Alpha,3beta)-2,3-dihydroxyolean-12-en-28-oic acid, a new natural triterpene from Olea europea, induces caspase dependent apoptosis selectively in colon adenocarcinoma cells

Triterpenoids are known to induce apoptosis and to be anti-tumoural. Maslinic acid, a pentacyclic triterpene, is present in high concentrations in olive pomace. This study examines the response of HT29 and Caco-2 colon-cancer cell lines to maslinic-acid treatment. At concentrations inhibiting cell growth by 50-80% (IC50HT29=61+/-1 microM, IC80HT29=76+/-1 microM and IC50Caco-2=85+/-5 microM, IC80Caco-2=116+/-5 microM), maslinic acid induced strong G0/G1 cell-cycle arrest and DNA fragmentation, and increased caspase-3 activity. However, maslinic acid did not alter the cell cycle or induce apoptosis in the non-tumoural intestine cell lines IEC-6 and IEC-18. Moreover, maslinic acid induced cell differentiation in colon adenocarcinoma cells. These findings support a role for maslinic acid as a tumour suppressant and as a possible new therapeutic tool for aberrant cell proliferation in the colon. In this report, we demonstrate for the first time that, in tumoural cancer cells, maslinic acid exerts a significant anti-proliferation effect by inducing an apoptotic process characterized by caspase-3 activation by a p53-independent mechanism, which occurs via mitochondrial disturbances and cytochrome c release.     

Role of Integrins and Evidence for two Distinct Mechanisms Mediating Human Colorectal Carcinoma Cell Interaction with Peritoneal Mesothelial Cells and Extracellular Matrix

Peritoneal carcinomatosis involves a series of events including tumor cell interactions with mesothelial cells and the extracellular matrix (ECM). We have studied the adhesive and invasive properties of four human colorectal carcinoma cell lines (Co115, HT29, SW480, SW620) confronted in vitro with a human mesothelial cell monolayer or with the ECM proteins collagen IV, laminin-1, fibronectin, tenascin-C and vitronectin. Quantitation was achieved following staining of tumor cells with the calcein-AM fluorescent dye. We found that all four cell lines rapidly adhered to a mesothelial cell monolayer. This adhesion event was not inhibitable by anti-integrin and anti-CD44 antibodies. Following initial attachment, the SW480 and SW620 cells invaded the mesothelial cell monolayer more aggressively than HT29 and Col 15 cells. All cell lines adhered to ECM proteins with each one exhibiting an individual adhesion pattern. Adhesion to matrix was completely integrin-dependent. When tested in an invasion assay, HT29 and Co115 cells crossed Matrigel-coated filters while SW480 and SW620 cells did not. This invasion was inhibited by anti-β1 integrin antibodies. Taken together, our results demonstrate that the initial colorectal tumor cell—mesothelial cell interaction occurs through an integrin-independent mechanism while adhesion to matrix proteins and invasion through Matrigel are integrin-dependent events. Furthermore, the different invasive capacity of SW480 and SW620 versus HT29 and Co115 cells upon interaction with a mesothelial cell monolayer or Matrigel suggests that these two invasion events may be mediated by distinct mechanisms.     

The 5-hydrazino-3-methylisothiazole-4-carboxylic acid,its new 5-substituted derivatives and their antiproliferative activity

Currently, the basic method of treatment of colon cancer is surgery. The range of anticancer drugs used in the treatment of colorectal cancer is small and is based mainly on systemic combination chemotherapy. As a result of the designed syntheses, we received new isothiazole derivatives with anticancer activity. The synthesized 5-hydrazino-3-methylisothiazole-4-carboxylic acid has never been obtained before. It is also a substrate for the synthesis of its innovative derivatives, i.e. compounds that are Schiff bases. The identification of the structure of new compounds was carried out using mass spectrometry (MS), proton nuclear magnetic resonance spectroscopy (¹H NMR), carbon nuclear magnetic resonance spectroscopy (¹³C NMR) and infrared spectroscopy (IR). Potential antitumor activity was confirmed in antiproliferative MTT and SRB tests. The selected, most biologically active substances were characterized by high selectivity towards leukemia and colon cancer cell lines. They caused high inhibition of proliferation of human biphenotypic B cell myelomonocytic leukemia MV4-11 (13 compounds), human colon adenocarcinoma cell lines sensitive LoVo (8 compounds) and resistant to doxorubicin LoVo/DX (12 compounds). However, in the conducted studies, their activity against breast adenocarcinoma MCF-7 and normal non-tumorigenic epithelial cell line derived from mammary gland MCF-10A was substantially lower. The result of this work is claimed Polish patent application.     

Adriamycin (ADM) induced apoptosis in Transitional Cell Cancer (TCC) cell lines accompanied by p21 WAF1/CIP1 induction

Genotoxic stimuli, including anticancer drugs, induce apoptosis in cancer cells through increase of p53, p21WAF1/CIP1 , at least in part. Bcl-2 and Bax modify this pathway or directly regulated by p53. Here we studied Adriamycin (ADM)-induced apoptosis in four human bladder cancer cell lines in respect of p53, p21WAF1/CIP1 and Bcl-2 family proteins. After ADM, treatment bladder cancer cells underwent dose-dependent cell death with typical morphologic features of apoptosis. Among four cell lines RT4 with wt p53, low ratio of Bcl-2 to Bax and induction of p21WAF1/CIP1 after ADM treatment, was the most sensitive to induction of apoptosis. Thus, p53, p21WAF1/CIP1 , Bcl-2 and Bax status might determine susceptibility of bladder cancer cells to ADM induced apoptosis.     

Anti-Fas antibody-induced apoptosis in human colorectal carcinoma cell lines: role of the p53 gene

The cell surface Fas antigen transducts an apoptotic signal by its crosslinking with Fas ligand or anti-Fas antibody in a variety of human cultured cells. In this study, we examined the expression of Fas antigen and its mediation of apoptosis in six human colorectal carcinoma cell lines. A flow cytometric analysis revealed that LoVo, DLD-1, WiDr and SW837 cell lines showed higher expression levels of Fas antigen, in contrast to lower expression in COLO201 and COLO320DM. Interferon- enhanced the expression of Fas antigen in all of the cell lines examined. Both Fas ligand and Fas-associated phosphatase-1 (FAP-1) were expressed only in COLO320DM. Anti-Fas antibody induced apoptosis in LoVo carrying wild-type p53 gene, but not in the other five cell lines carrying mutated p53 gene. The transfection of wild-type p53 gene using an adenovirous vector upregulated P53 protein in WiDr and SW837 cells, both of which showed, however, no increase in apoptotic cells by anti-Fas antibody treatment. These results indicated that (1) Fas antigen was variably expressed, regardless of the p53 gene status and (2) the susceptibility to anti-Fas antibody-mediated apoptosis did not correlate to Fas, Fas ligand or FAP-1 expression levels. Therefore, we conclude that wild-type P53 expression might not necessarily be essential for Fas-mediated apoptosis in human colorectal carcinoma cell lines.