Changes in the expression of cyclin G2 in esophageal cancer cell and its significance

Abstract

This study aimed to analyze the expression, clinical significance of cyclin G2 (CCNG2) in esophageal carcinoma, and the biological effect in its cell line by CCNG2 overexpression. Immunohistochemistry and western blot were used to analyze CCNG2 protein expression in 73 cases of esophageal cancer and normal tissues to study the relationship between CCNG2 expression and clinical factors. CCNG2 lentiviral vector and empty vector were respectively transfected into esophageal cancer Eca-109 cell line. Reverse transcription-polymerase chain reaction and western blot were used to detect the mRNA level and protein of CCNG2. MTT assay and cell cycle were also conducted as to the influence of the upregulated expression of CCNG2 that might be found on Eca-109 cell's biological effect. Immunohistochemistry: The level of CCNG2 protein expression was found to be significantly lower in esophageal cancer tissue than normal tissues (P < 0.05). Western blot: The relative amount of CCNG2 protein in esophageal cancer tissue was respectively found to be significantly lower than in normal tissues (P < 0.05). The level of CCNG2 protein expression was not correlated with gender, age, and tumor size (P > 0.05), but it was correlated with lymph node metastasis, clinic stage, and histological grades (P < 0.05). Loss of CCNG2 expression correlated significantly with poor overall survival time by Kaplan-Meier analysis. The result of the biological function showed that Eca-109 cell-transfected CCNG2 had a lower survival fraction, more percentage of the G0/G1 phases (P < 0.05), and lower cyclin-dependent kinase 2 (CDK2) protein expression. CCNG2 expression decreased in esophageal cancer and correlated significantly with lymph node metastasis, clinic stage, histological grade, and poor overall survival, suggesting that CCNG2 may play important roles as a negative regulator to esophageal cancer cell by promoting degradation of CDK2.

Cyclin G2: A novel independent prognostic marker in pancreatic cancer

“…Previous studies have reported that CCNG2 participates in carcinogenesis and is a known tumor suppressor gene (15)(16)(17)(20)(21)(22)(23)(24)(25)(26). CCNG2 gene expression is downregulated in thyroid (20), oral (21), ovarian (22), breast (23,24), gastric (16), esophageal (17), prostate (25), kidney (26) and colorectal (15) cancer cells.…”

“…Furthermore, our previous study demonstrated that CCNG2 was associated with chemoresistance and cancer stemness via cell apoptosis in pancreatic cancer (13). Recently, CCNG2 has been reported as a novel prognostic marker in several types of cancer (14)(15)(16)(17). However, to date, no study has clarified the association between CCNG2 and the prognosis of pancreatic cancer.…”

“…Cyclins positively regulate cell proliferation to a large extent. However, unexpectedly, CCNG2 has been reported to regulate cell proliferation as a tumor suppressor gene and its decreased expression is associated with malignant phenotypes in several types of cancer (8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Previous studies have reported that CCNG2 is involved in a variety of functions associated with cancer progression, including the regulation of cell proliferation (8-10), chemoresistance (8), DNA repair (11) and cell differentiation (12).…”

MicroRNA-93 regulates cyclin G2 expression and plays an oncogenic role in laryngeal squamous cell carcinoma

“…Previous data showed that as a key negative regulator of cell cycle proliferation, apoptosis, cell death signaling, and even carcinogenesis, suggesting that the decreased expression levels of CCNG2 significantly correlates with tumor progression and unfavorable prognosis, such as studies in colorectal carcinoma, kidney, esophageal, oral cancer, gastric carcinoma, prostate cancer and papillary carcinoma of the thyroid (29)(30)(31)(32)(33)(34)(35). In the present study, we found that CCNG2 expression was markedly decreased in the LSCC tissues compared with the adjacent normal tissues and lower expression of CCNG2 tended to have more advanced clinical stage.…”

MicroRNA-1246 promotes growth and metastasis of colorectal cancer cells involving CCNG2 reduction

“…The expression of CycG2 is repressed by mitogens, however, is upregulated during cell cycle arrest responses to antiproliferative signals (16). The expression of CycG2 decreased in thyroid cancer, esophageal, prostate, kidney and gastric cancer tissues and cells, and is significantly correlated with lymph node metastasis, clinical stage, histological grade and poor overall survival, suggesting that CCNG2 may be important as a negative regulator in thyroid cancer K1 cells by promoting the degradation of CDK2 (17)(18)(19)(20)(21). In addition, abnormal expression of CycG2 was observed in nasopharyngeal carcinoma cells and was closely associated with tumor differentiation, origin and progression (22).…”