The role of c2orf68 and PI3K/Akt/mTOR pathway in human colorectal cancer

Abstract

The aim of the research is to determine whether c2orf68 gene plays a role in the carcinogenesis of human colorectal cancer and to study the function of c2orf68 belonging to the UPF0561 family. The mRNA expression levels of c2orf68 were examined in 30 pairs of human colorectal adenocarcinoma tissues and adjacent normal colorectal tissues by qRT-PCR. The SW480 and SW620 cell lines were transfected with siRNA against the c2orf68 gene and set gene. The expressed mRNA levels of Akt, PI3K, Bax, Bcl-2, caspase3, c-Myc, cyclinD1, pp2a and set were determined by qRT-PCR, and the protein levels of C2ORF68, c-Myc, PP2A and SET were examined by Western blot. Cell proliferation was tested by MTT assay, and apoptosis and cell cycle were studied by flow cytometry. Cancer metastasis assay was performed by transwell chamber. The c2orf68 mRNA expression was down-regulated in 63.33 % of the cancer samples, and a positive correlation was found between the mRNA expression of c-Myc and pp2a that of c2orf68. Meanwhile, there was a negative correlation between the mRNA expression of c2orf68 and set. The c2orf68 mRNA was significantly down-regulated in SW480(-c2orf68) and SW620(-c2orf68) cells. The inhibitory rate in the two cell lines was, respectively, 65.2 and 71.6 % by qRT-PCR. A 22.7 % inhibition on cell proliferation in SW480(-c2orf68) cells and a 21.2 % inhibition in SW620(-c2orf68) cells were observed using the MTT assay. Flow cytometry analysis indicates that the cell apoptosis rate was 21.42 % in SW480(-c2orf68) cells and 17.78 % in SW620(-c2orf68) cells, whereas the percentage of G1 phase cells was 61.8 and 58.6 % in SW480(-c2orf68) and SW620(-c2orf68) cells, respectively. In addition, the mRNA expression of set and Bax was up-regulated after c2orf68 interfered in SW480(-c2orf68) and SW620(-c2orf68) cells, whereas that of Bcl-2, c-Myc, cyclinD1, caspase3 and pp2a was down-regulated. Consistent with the mRNA results, the protein expression of C2ORF68, PP2A and c-Myc was down-regulated, whereas that of SET was up-regulated. Our data thus suggest that c2orf68 promotes carcinogenesis through the regulation of mammalian target of rapamycin signaling pathway.

Interaction between C2ORF68 and HuR in human colorectal cancer

“…Our study revealed that cell apoptosis increased, cell proliferation and cell migration decreased when c2orf68 was inhibited in SW480 cells. These results are consistent with our previous study (16). In addition, we also demonstrated that cell apoptosis increased while cell proliferation and cell migration decreased in SW480 -HuR and SW480 -c2orf68,-HuR cells.…”

“…The cell apoptosis rate, cell proliferation and cell migration in SW480 -c2orf68,-HuR cells which has more significant results than that in SW480 -HuR cells revealed that c2orf68 and HuR may have a synergistic effect in regulating cell apoptosis, cell proliferation and cell migration. This study differed from our previous study (16), which focused on the PI3K/Akt/mTOR signaling pathway and its downstream molecules, such as Akt, PI3K, Bcl-2, c-Myc, cyclin D1 and bax when c2orf68 was inhibited. A recent study showed that the HuR expression level is closely related to AKT phosphorylation and PI3K/AKT/NF-κB signaling can notably elevate HuR gene transcription (18).…”

“…C2orf68 and HuR may co-regulate cell proliferation and apoptosis by upregulating Bcl-2, c-Myc, cyclin D and cyclin A gene expression and downregulating Bax gene expression, resulting in the development of colorectal cancer. Our previous study indicated that C2ORF68 can regulate cancer cell proliferation and apoptosis through PI3K/AKT/mTOR signaling (16). At the same time, a recent study (18) showed that the HuR expression level is closely related to AKT phosphorylation and cytoplasmic abundance of HuR in human cancer may be associate with oncogenic activation of AKT signaling.…”

“…The predicted potential NLS and NES sequences of C2ORF68 and the domain of the EF hand indicate that c2orf68 could function as a cell cycle regulator in the nucleus, which may explain its possible role in CRC pathogenesis. Our early research suggests that C2ORF68 may regulate colon cancer cell apoptosis, proliferation, migration and cell cycle distribution through the PI3K/Akt/mTOR pathway (16). We also suggested that C2ORF68 may promote the carcinogenesis of CRC and play a vital role in the pathogenesis of CRC through activation of the Wnt/β-catenin signaling pathway (17), such as the upregulation of β-catenin, survivin, cyclin D1 and c-Myc, and the downregulation of GSK-3β in CRC cells.…”

CDKN3 mRNA as a Biomarker for Survival and Therapeutic Target in Cervical Cancer

“…The use of specific siRNAs to block or inhibit the activity of a gene is a well-established methodology for in vitro models, particularly to investigate gene function [ 57 – 59 ]. However, the use of siRNAs as therapeutic agents in tumor models has not been entirely successful, especially for invasive or metastatic cancers [ 60 , 61 ].…”