Silence of the tumor suppressor miR-34c is implicated in the development of colorectal cancer (CRC). For the past few years, Resveratrol (Res) has been introduced to oncotherapies alone or with traditional chemotherapeutic drugs. However, the study of molecular mechanism involved in the anti-CRC effect of Res is still ongoing. The anti-CRC effect of Res alone or with Oxaliplatin (Oxa) was determined by cell viability assay, soft agar colony formation assay, flow cytometry and real-time cellular analyzer in HT-29 (p53 + ) and HCT-116 (p53 − ) CRC cell lines. Expressions of miR-34c and its targets were detected by qPCR and/or western blot. To evaluate the role of miR-34c in anti-CRC effect by Res alone or with Oxa, miR-34c was up or down-regulated by lentiviral mediation or specific inhibitor, respectively. To investigate how miR-34c was increased by Res, the methylation status of miR-34c promoter was detected by MSP. The tumor bearing mouse model was established by subcutaneous injection of HCT-116 cells to assess anti-CRC effect of Res alone or with Oxa in vivo. IL-6 and TNF-α in xenografts were detected by ELISA. Res inhibited cell viability, proliferation, migration and invasion as well as promoted apoptosis both in HT-29 and HCT-116 CRC cells. The anti-CRC effect of Res was partially but specifically through up-regulating miR-34c which further knocked down its target KITLG; and the effect was enhanced in the presence of p53 probably through inactivating PI3K/Akt pathway. Besides, Res sensitized CRC cells to Oxa in a miR-34c dependent manner. The xenograft experiments showed that exposure to Res or Oxa suppressed tumor growth; and the efficacy was evidently augmented by the co-treatment of Res and Oxa. Likewise, miR-34c level was elevated in xenografts of Res-treated mice while the KITLG was decreased. Finally, Res clearly reduced IL-6 in xenografts. Res suppressed CRC by specifically activating miR-34c-KITLG in vitro and in vivo; and the effect was strengthened in the presence of p53. Besides, Res exerted a synergistic effect with Oxa in a miR-34c dependent manner. We also suggested that Res-increased miR-34c could interfere IL-6-triggered CRC progression.

Li X, et al. J Gynecol Oncol. 2013 Apr;24(2):177-185. http://dx.doi.org/10.3802/jgo.2013.24.2.177

Although it is well known that the reduction of interstitial cells of Cajal (ICCs) is associated with several gastrointestinal motility disorders in clinic, it is unknown whether the mature ICCs still have an active plasticity in adult mammals. This study focused on the issues of the reduction of ICCs during Imatinib administration and the recovery of ICCs following drug withdrawal in the small intestine of adult guinea pigs. ICCs were revealed by immunofluorescence on whole mount preparations with anti‐Kit, α‐smooth muscle actin, (α‐SMA), and 5‐bromo‐2′‐deoxyuridine (BrdU) antibodies. Moreover, the occurrence of apoptosis was also assayed. Imatinib treatment led to a gradual reduction of ICCs in number around the myenteric plexus and deep muscular plexus, which was dependent on the time but no apoptosis of ICCs was detected with the TUNEL method. During Imatinib treatment, some ICC‐like cells were double labeled for Kit and α‐SMA and a few ICC‐like cells were only stained with α‐SMA. When Imatinib was discontinued, the number of ICCs recovered to normal within 32 days. During this time, some proliferating ICCs were demonstrated by double labeling with Kit and BrdU antibodies. Our results indicated that Kit signaling was essential for the maintenance of survival and proliferation of the mature ICCs in the small intestine of adult guinea pigs. Moreover, ICCs might transdifferentiate to a type of α‐SMA⁺ cells, perhaps a phenotype of smooth muscle cells, when there is a loss‐of‐function of Kit. Anat Rec, 292:985–993, 2009.

MiR‐34c is considered a potent tumour suppressor because of its negative regulation of multiple target mRNAs that are critically associated with tumorigenesis and metastasis. In the present study, we demonstrated a novel target of miR‐34c, KITLG, which has been implicated in colorectal cancer (CRC). First, we found a significant negative relationship between miR‐34c and KITLG mRNA expression levels in CRC cell lines, including HT‐29, HCT‐116, SW480 and SW620 CRC cell lines. In silico analysis predicted putative binding sites for miR‐34c in the 3′ untranslated region (3′UTR) of KITLG mRNA. A dual‐luciferase reporter assay further confirmed that KITLG is a direct target of miR‐34c. Then, the cell lines were infected with lentiviruses expressing miR‐34c or a miR‐34c specific inhibitor. Restoration of miR‐34c dramatically reduced the expression of KITLG mRNA and protein, while silencing of endogenous miR‐34c increased the expression of KITLG protein. The miR‐34c‐mediated down‐regulation of KITLG was associated with the suppression on proliferation, cellular transformation, migration and invasion of CRC cells, as well as the promotion on apoptosis. Knockdown of KITLG by its specific siRNA confirmed a critical role of KITLG down‐regulation for the tumour‐suppressive effects of miR‐34c in CRC cells. In conclusion, our results demonstrated that miR‐34c might interfere with KITLG‐related CRC and could be a novel molecular target for CRC patients.

C-kit signaling promotes proliferation and invasion of colorectal mucinous adenocarcinoma in a murine model C-kit signaling promotes proliferation and invasion of colorectal mucinous adenocarcinoma in a murine model