ObjectiveTo further understand function of circular RNA (circRNA) and explore its relationship with occurrence and development of gastric cancer and its value in diagnosis and prognosis of gastric cancer.MethodThe published literatures on the circRNA function and its relationship with gastric cancer were reviewed and summarized.ResultsThe closed loop structure of circRNA made it was enzymatically stable. At present, it was clear that the circRNA acted as a microRNA (miRNA) sponge and regulated the gene transcription by binding with the corresponding sites, even could be as a translation template to participate in the protein translation. Further the circRNA could act on the target gene regulated by the miRNA through the miRNA sponge. The biosignal pathway involved in the development of gastric cancer regulated by the growth of gastric cancer cells. The circRNA was differentially expressed in the gastric cancer tissue and its adjacent tissue as well as in the serums of patient and healthy human, which had the close relationships with the clinical features (pathological staging, lymph node metastasis, distant metastasis, CEA, CA19-9, etc.) and the poor prognosis and shorter postoperative survival time of patients with gastric cancer.ConclusionsDue to structural characteristics of circRNA closed loop, it has an enzyme stability and can play a variety of biological functions based on miRNA sponge. Differential expression of circRNA in gastric cancer is expected to play an important role in diagnosis and prognosis evaluation of gastric cancer.
Objective To summarize research progress of relationship between chloride intracellular channel protein 1 (CLIC1) and colonic cancer. Method The related literatures in recent years on the relationship between the CLIC1 and the colonic cancer were reviewed and analyzed. Results The CLIC1 could play its physiological function as a chloride ion channel, with a wide tissue distribution and high expression in many tumor tissues. The abnormal expression of CLIC1 could result in many diseases and participate in many processes such as the occurrence, development, metastasis, and treatment of the colonic cancer. Conclusions CLIC1 might be a biomarker for early diagnosis and a target for gene therapy of colonic cancer, key genes regulated its expression, signal transduction pathways involved in occurrence and progression of colonic cancer, and interaction with other related molecules are still unclear, and further study is needed.
ObjectiveTo understand the function of long non-coding RNA (lncRNA) colon cancer associated transcript-1 (CCAT1) and summarize its relationship with gastric cancer.MethodThe published literatures on the studies of lncRNA CCAT1 function and its relationship with gastric cancer were reviewed and analyzed.ResultsThe lncRNA CCAT1 exerted the negative regulation on the genes by binding to microRNAs (miR) as a competitive endogenous RNA, mediating chromatin circulation between the c-MYC promoter and its upstream enhancer, and promoted the expression of c-MYC gene. The recent studies had found that the CCAT1 could bind to the miR-219-1 and miR-490, thereby promoting the progress of gastric cancer. The expression of lncRNA CCAT1 in the gastric cancer tissues increased, which was obviously different from that in the paracancer tissues and normal tissues. The high expression of lncRNA CCAT1 was related to the tumor size, lymphatic metastasis and TNM stage.ConclusionsThe specific mechanism, intracellular signal transduction pathway and interaction mechanism between CCAT1 and other molecules involved in the progress of gastric cancer still need to be further explored. With the in-depth study of lncRNA, especially CCAT1, it may provide a broader prospect for the diagnosis and treatment of gastric cancer as a target of CCAT1.
Objective To establish a xenograft model of hydroxycamptothecine (HCPT)-resistant human gastric cancer cell line (SGC-7901/HCPT) in nude mice and study its biological characteristics. Methods The SGC-7901 and SGC-7901/ HCPT cells were cultured in vitro. The cell suspension was injected subcutaneously into the nude mice. When the subcutaneous carcinoma was 1.0 cm in diameter, it was cut off and divided into pieces of 0.1-0.2 cm in diameter． Then the small pieces of tumor were re-transplanted subcutaneously into the second generation nude mice until the fourth generation. The morphological feature, ultramicro-structure, and growth characteristics of the fourth generation transplanted tumor were examined. The drug resistance was measured by methyl thiazolyl tetrazolium (MTT) assay. Results The transplanted tumor in nude mice was round or oval, and many blood vessels were on its surface. Under the light microscope, the sizes of SGC-7901 transplanted tumor cells were similar, and sizes of cell nuclei were also similar; Meanwhile, the morphous of SGC-7901/HCPT transplanted tumor cells were irregular and in disorder, and the size of the cell nuclei was different from each other. Under the electron microscope, the mitochondria and endoplasmic reticulum of SGC-7901 transplanted tumor cells were nearly normal and no swelling in cell nuclei; Meanwhile the cell nuclei of SGC-7901/HCPT transplanted tumor cells were lightly swelled, a the mitochondria and endoplasmic reticulum were obviously swelled. By MTT assay, compared with SGC-7901 transplanted tumor cells, the resistance index of SGC-7901/HCPT transplanted tumor cells was 9.02±0.78 in HCPT, and resistance index to Adriamycin， Mitomycin C, 5-fluorouracil, and Etoposide was 1.24±0.09, 1.31±0.17, 0.96±0.12, and 1.07±0.16, respectively. Conclusions A transplanted tumor model of SGC-7901/HCPT in nude mice is established successfully， and showing stable drug resistance to HCPT and no cross-resistance to other chemotherapeutics, which can be used for further experiments.