cerulenin and Colonic-Neoplasms

Sonic hedgehog (SHH) signaling is essential in normal development of the gastrointestinal (GI) tract, whereas aberrantly activated SHH is implicated in GI cancers because it facilitates carcinogenesis by redirecting stem cells. Since colitis-associated cancer (CAC) is associated with inflammatory bowel diseases, in which SHH and IL-6 signaling, inflammation propagation, and cancer stem cell (CSC) activation have been implicated, we hypothesized that SHH inhibitors may prevent CAC by blocking the above SHH-related carcinogenic pathways. In the intestinal epithelial cells IEC-6 and colon cancer cells HCT-116, IL-6 expression and its signaling were assessed with SHH inhibitors and levels of other inflammatory mediators, proliferation, apoptosis, tumorsphere formation, and tumorigenesis were also measured. CAC was induced in C57BL/6 mice by administration of azoxymethane followed by dextran sodium sulfate administration. SHH inhibitors were administered by oral gavage and the mice were sacrificed at 16 weeks. TNF-α-stimulated IEC-6 cells exhibited increased levels of proinflammatory cytokines and enzymes, whereas SHH inhibitors suppressed TNF-α-induced inflammatory signaling, especially IL-6/IL-6R/gp130 signaling. SHH inhibitors significantly induced apoptosis, inhibited cell proliferation, suppressed tumorsphere formation, and reduced stemness factors. In the mouse model, SHH inhibitors significantly reduced tumor incidence and multiplicity, decreased the expression of IL-6, TNF-α, COX-2, STAT3, and NF-κB, and significantly induced apoptosis. In colosphere xenografts, SHH inhibitor significantly suppressed tumorigenesis by inhibiting tumorsphere formation. Taken together, our data suggest that administration of SHH inhibitors could be an effective strategy to prevent colitis-induced colorectal carcinogenesis, mainly by targeting IL-6 signaling, ablating CSCs, and suppressing oncogenic inflammation, achieving chemoquiescence ultimately.

Topics: Animals; Apoptosis; Azoxymethane; Blotting, Western; Cell Movement; Cell Proliferation; Cerulenin; Colitis; Colonic Neoplasms; Cytokine Receptor gp130; Fatty Acid Synthesis Inhibitors; Flow Cytometry; Fluorescent Antibody Technique; Hedgehog Proteins; Humans; Hydroxyprostaglandin Dehydrogenases; Immunoenzyme Techniques; Interleukin-6; Male; Mice; Mice, Inbred C57BL; Proto-Oncogene Proteins c-bcl-2; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Spheroids, Cellular; Tumor Cells, Cultured; Xenograft Model Antitumor Assays; Zinc Finger Protein GLI1

Fatty acid synthase is highly expressed in many types of human cancers. Cerulenin, a natural inhibitor of fatty acid synthase, induced apoptosis in the human colon cancer cell lines HCT116 and RKO. Oxaliplatin also induced cell death in these cell lines. Cerulenin treatment was associated with reduced levels of phosphorylated Akt, activation of p38 and induced caspase-3 cleavage and finally caused apoptosis. Oxaliplatin induced activation of the p53-p21 pathway and p38. In combination with cerulenin and oxaliplatin, activation of the p53-p21 pathway and p38 occurred in a smaller concentration and finally induced caspase-3 cleavage in a smaller concentration of cerulenin and oxaliplatin. In xenotransplanted SCID mice, the cerulenin + oxaliplatin group significantly inhibited tumor progression compared to the control, cerulenin and oxaliplatin groups. Based on these studies, inhibiting fatty acid synthase would be an effective strategy to treat unresectable colorectal cancer tumors in combination with oxaliplatin. Fatty acid synthase inhibitor would be one of the best counterparts of oxaliplatin, which reduces the dose and side-effects of oxaliplatin and would make it possible to endure the chemotherapy over a longer period.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cerulenin; Colonic Neoplasms; Fatty Acid Synthases; Fatty Acid Synthesis Inhibitors; HCT116 Cells; Humans; Mice; Neoplasm Transplantation; Organoplatinum Compounds; Oxaliplatin

Fatty acid synthase (FAS) is highly expressed in many kinds of human cancers, including colorectal cancer (CRC), and we have investigated the potential use of FAS inhibitors for chemoprevention of liver metastasis of CRC in mice. Expression of FAS was evaluated in murine CRC cell lines Colon 26 and CMT 93. Cerulenin, a natural inhibitor of FAS, induced apoptosis in these cell lines. The ability of cerulenin to prevent development of liver metastatic lesions in Colon 26 was evaluated. The numbers and sizes of liver metastatic CRC tumors were significantly reduced by treating mice with cerulenin. Cerulenin treatment was associated with reduced levels of phosphorylated Akt in Colon 26 cells, suggesting that inhibition of this signal transduction pathway might be involved in the chemopreventive activity of this compound. Based on studies in mouse models, inhibiting FAS would be an effective strategy to prevent and retard growth of liver metastatic tumors of CRC that have high expression of this enzyme.

Topics: Animals; Caspases; Cell Line, Tumor; Cerulenin; Colonic Neoplasms; Dose-Response Relationship, Drug; Fatty Acid Synthases; Lipogenesis; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred BALB C

Endogenous fatty acid synthesis has been observed in certain rapidly proliferating normal and neoplastic tissues. Sterol regulatory element-binding proteins (SREBPs) are transcription factors that regulate the expression of lipogenic genes including fatty acid synthase (FAS), the major biosynthetic enzyme for fatty acid synthesis. We have previously shown that SREBP-1, FAS, and Ki-67, a proliferation marker, colocalized in the crypts of the fetal gastrointestinal tract epithelium. This study sought to determine whether SREBP-1 participates in the regulation of proliferation-associated fatty acid synthesis in colorectal neoplasia. An immunohistochemical analysis of SREBP-1, FAS, and Ki-67 expression in 25 primary human colorectal carcinoma specimens showed colocalization in 22 of these. To elucidate a functional linkage between SREBP-1 activation and proliferation-associated FA synthesis, SREBP-1 and FAS content were assayed during the adaptive response of cultured HCT116 colon carcinoma cells to pharmacological inhibition of FA synthesis. Cerulenin and TOFA each inhibited the endogenous synthesis of fatty acids in a dose-dependent manner and each induced increases in both precursor and mature forms of SREBP-1. Subsequently, both the transcriptional activity of the FAS promoter in a luciferase reporter gene construct and the FAS expression increased. These results demonstrate that tumor cells recognize and respond to a deficiency in endogenous fatty acid synthesis by upregulating both SREBP-1 and FAS expression and support the model that SREBP-1 participates in the transcriptional regulation of lipogenic genes in colorectal neoplasia.

Topics: CCAAT-Enhancer-Binding Proteins; Cell Division; Cerulenin; Colonic Neoplasms; Colorectal Neoplasms; DNA-Binding Proteins; fas Receptor; Fatty Acid Synthases; Furans; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Hypolipidemic Agents; Ki-67 Antigen; Mitotic Index; Promoter Regions, Genetic; Recombinant Fusion Proteins; Sterol Regulatory Element Binding Protein 1; Transcription Factors; Transfection; Tumor Cells, Cultured

To investigate whether cerulenin could induce apoptosis and suppress the proliferation of human colonic cancer cells.. Cell morphology, microculture tetrazolium assay (MTT), agarose gel electrophoresis and flow cytometry assays were performed to identify the inhibitory effect on cell proliferation and the induction of apoptosis in human colonic cancer cells (LoVo).. Cerulenin was able to induce LoVo cells death via apoptosis. Cerulenin also inhibited the proliferation of LoVo cells in vitro and was dose-dependent. Nuclear DNA of apoptotic cells displayed ladder bands characteristic of internucleosomal DNA fragmentation and apoptotic peak. The inhibitory effect of cerulenin on proliferation of LoVo cells was associated with cell cycle arrest from S to G(2)-M phase transition and with induction of apoptosis. In contrast, cerulenin could not affect the proliferation of human fibroblasts in vitro.. The fatty acid synthase inhibitor, cerulenin, enables to induce cell apoptosis and to suppress the growth of human colonic cancer cells by inhibition of the synthesized fatty acids endogenously in the cancer cells.

Topics: Apoptosis; Cell Division; Cell Line, Tumor; Cerulenin; Colonic Neoplasms; DNA Fragmentation; Fatty Acid Synthases; Fibroblasts; Humans

To determine the effects of fatty acid synthase inhibitor, cerulenin, on tumor growth of human colonic carcinoma (LoVo) in nude mice.. The transplantable colonic carcinoma cell line LoVo model was established in BALB/CA-nu/nu mice by subcutaneous implantation. Cerulenin was administrated by i.p. injection (80 mg/kg, 160 mg/kg each time) for 10 times. 17 days later the mice were killed and tumor size evaluated.. The size of tumors in cerulenin-treated group were significantly smaller than in control group and were similar to that of the 5-Fu treated group. Transmission electronic microscopy (TEM) revealed that death of LoVo cells treated by cerulenin was associated with apoptosis characterized by cell shrinkage, condensation and chromosome fragmentation. bcl-2 oncoprotein expression rate was significantly lower in cerulenin-treated group in comparing with the control group. The expression rate of bax was the opposite to that of bcl-2.. Cerulenin effectively suppresses the growth of human colonic carcinoma cells in vivo. The mechanism of cell death may be correlated with apoptosis, and bcl-2 and bax gene may play an important role in regulating cerulenin-induced apoptosis.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Cell Line, Tumor; Cerulenin; Colonic Neoplasms; Dose-Response Relationship, Drug; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Proto-Oncogene Proteins c-bcl-2