Prediction and identification of immune genes related to the prognosis of patients with colon adenocarcinoma and its mechanisms.

BACKGROUND: Colon adenocarcinoma (COAD) is a gastrointestinal tumor with a high degree of malignancy. Its deterioration process is closely related to the tumor microenvironment, and transcription factors (TF) play a regulatory role in this process. Currently, there is a lack of exploration between the genes related to the COAD tumor microenvironment and the survival prognosis of patients. Models composed of multiple genes usually predict the survival prognosis of patients more accurately than single genes. We can analyze the multigene models that can predict the prognosis of COAD from the current database. METHODS: The limma package of the R programming language is used for gene differential expression analysis. Kaplan-Meier curve is used to analyze the relationship between the patient risk score model and survival data. The hazard model is used to analyze the relationship between the risk score and the clinical data of COAD patients. The information of immune genes and immune cells is obtained from IMMPORT database and TIMER database. Receiver operating characteristic (ROC) curve is used to judge the stability of the model. RESULTS: We found 7 immune genes, which can built a risk score model to predict the survival prognosis of COAD. According to univariate and multivariate analysis, the risk score can be used as an independent predictor. The content of some immune microenvironment cells will also increase as the risk score increases. CONCLUSIONS: We found 7 immune genes, such as SLC10A2 (solute carrier family 10 member 2), CXCL3 (C-X-C motif chemokine ligand 3), IGHV5-51 (immunoglobulin heavy variable 5-51), INHBA (inhibin subunit beta A), STC1 (stanniocalcin 1), UCN (urocortin), and OXTR (oxytocin receptor), can constitute a model for predicting the prognosis of COAD. They may provide potential therapeutic targets for clinical treatment of COAD.

Antisense bcl-2 retrovirus vector increases the sensitivity of a human gastric adenocarcinoma cell line to photodynamic therapy.

The bcl-2 oncoprotein directly prolongs cellular survival by blocking apoptosis and its overexpression is associated with cellular resistance to killing by chemotherapeutic drugs and gamma-irradiation. Meanwhile, it has been shown that bcl-2 antisense oligonucleotide can induce apoptosis or increase toxicity of the treatment in tumors in vivo and in vitro. However, it is difficult to obtain stable transfection by this approach and there are no reports about the effect of an antisense bcl-2 on the sensitivity to oxidative stress induced by photodynamic therapy (PDT). Here we investigated the effect of an antisense bcl-2 RNA retrovirus vector transfer on the sensitivity of 2-butylamino-2-demethoxy-hypocrellin A (2-BA-2-DMHA) photosensitization in a human gastric adenocarcinoma MGC803 cell line. The results indicate that antisense bcl-2-infected MGC803 cells expressed exogenous antisense bcl-2 mRNA measured by reverse transcription polymerase chain reaction and significantly reduced bcl-2 protein determined by western blotting analysis. The decreased expression of bcl-2 protein was accompanied by increased phototoxicity and susceptibility to apoptosis induced by 2-BA-2-DMHA PDT. Our finding suggests that reduction of bcl-2 protein in gastric cancers, and possibly also in a variety of other tumors, may be a novel and rational approach to improve photosensitivity and the treatment outcome.