Research on radiotherapy related genes and prognostic target identification of rectal cancer based on multi-omics.

BACKGROUND: Radiosensitivity of rectal cancer is related to the radiotherapy efficacy and prognosis of patients with rectal cancer, and the genes and molecular mechanisms related to radiosensitivity of rectal cancer have not been clarified. We explored the radiosensitivity related genes of rectal cancer at a multi omics level. METHODS: mRNA expression data and rectum adenocarcinoma (READ) data were obtained from the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus Database (GEO) (GSE150082, GSE60331, GSE46862, GSE46862). Differentially expressed genes between radiotherapy sensitive group and radiotherapy insensitive group were screened. GO analysis and KEGG pathway analysis were performed for differentially expressed genes. Among the differentially expressed genes, five core genes associated with rectal cancer prognosis were selected using random survival forest analysis. For these five core genes, drug sensitivity analysis, immune cell infiltration analysis, TISIDB database immune gene correlation analysis, GSEA enrichment analysis, construction of Nomogram prediction model, transcriptional regulatory network analysis, and qRT-PCR validation was performed on human rectal adenocarcinoma tissue. RESULTS: We found that 600 up-regulated genes and 553 down-regulated genes were significantly different between radiotherapy sensitive group and radiotherapy insensitive group in rectal cancer. Five key genes, TOP2A, MATR3, APOL6, JOSD1, and HOXC6, were finally screened by random survival forest analysis. These five key genes were associated with different immune cell infiltration, immune-related genes, and chemosensitivity. A comprehensive transcriptional regulatory network was constructed based on these five core genes. qRT-PCR revealed that MATR3 expression was different in rectal cancer tissues and adjacent non-cancerous tissues, while APOL6, HOXC6, JOSD1, and TOP2A expression was not different. CONCLUSION: Five radiosensitivity-related genes related to the prognosis of rectal cancer: TOP2A, MATR3, APOL6, JOSD1, HOXC6, are involved in multiple processes such as immune cell infiltration, immune-related genes, chemosensitivity, signaling pathways and transcriptional regulatory networks and may be potential biomarkers for radiotherapy of rectal cancer.

Correlation between Preoperative Platelet Count/(Lymphocyte Count × Prealbumin Count) Ratio and the Prognosis of Patients with Gastric Cancer Undergoing Radical Operation.

Objective: To clarify the relationship between preoperative platelet count/(lymphocyte count × prealbumin count) ratio (PLPR) and the prognosis of patients with gastric cancer undergoing a radical operation, combined with Tumor Node Metastasis (TNM) staging, a scoring system was established to guide clinical application. Methods: The clinical data of 238 patients receiving radical operations for gastric cancer were retrospectively analyzed. According to the area under the Receiver operating characteristic curve, the predictive value of the preoperative PLPR for the 5-year overall survival (OS) of gastric cancer was determined, and the best cut-off value of the ratio was corresponding to the maximum value of Yoden index. Chi-squared test was applied to analyze the correlation between the ratio and clinicopathological features. Kaplan-Meier curve was applied to analyze the influence of this ratio on 5-year OS. The Cox regression model was applied to analyze the hazards affecting the long-term survival of patients. The nomogram model was used to predict the long-term survival rate. Results: The optimal cut-off point of preoperative PLPR ratio was 7.46, and the patients were segmented into two sets: one set of ratio <7.46 and another set of ratio ≥7.46. The ratio was correlated with the size of the tumor, T stage, N stage, total stage, vascular cancer thrombus, and nerve invasion. In stage I-III patients, the prognosis was better in the low-ratio set than in the high-ratio set (P < 0.001), subgroup analysis indicated the prognosis was obviously better in the low-ratio set than in the high-ratio set in stage II and III patients (P < 0.05 and P < 0.001), but there was no difference in stage I patients (P > 0.05). Age, T stage, N stage, total TNM stage, tumor size, vascular tumor thrombus, nerve invasion, preoperative neutrophil count/lymphocyte count (NLR; reference value 3.68), preoperative PLPR (reference value 7.46), preoperative platelet count/lymphocyte count (PLR; reference value 159.56), and preoperative platelet count × NLR (SII; reference value 915.48) were related to patient prognosis (P < 0.05); meanwhile age, total TNM stage, preoperative PLPR (reference value 7.46), preoperative PLR (reference value 159.56), and preoperative SII (reference value 915.48) were independent hazards for prognosis (P < 0.05). Five independent risk factors were analyzed by nomogram model to predict the 5-year OS of patients who underwent a radical operation for carcinoma of the stomach. Conclusion: Preoperative PLPR ratio (reference value 7.46) is an independent risk factor for long-term prognosis in patients undergoing a radical operation for gastric cancer. The nomogram scoring system established by postoperative TNM staging combined with this ratio and age, PLR, and SII can better forecast the survival of patients who underwent radical operation for carcinoma of the stomach.

Expression of pyroptosis-related genes are correlated with immune microenvironment and predict prognosis in ESCA.

OBJECTIVES: Pyroptosis-related genes (PRGs) are abnormally expressed in a variety of gastrointestinal tumors, this study aimed to investigate the role of pyroptosis genes in assessing the prognosis of esophageal cancer (ESCA). METHODS: Through consensus clustering, we identified two subtypes associated with PRGs. After Lasso regression and multivariate Cox regression analysis, a polygenic signature based on six prognostic PRGS was constructed. Afterwards, we combined the risk score with clinical predictors to construct and validate a PRGs-associated ESCA prognostic model. RESULTS: Through analysis, we Successfully constructed and validated a PRGs-associated ESCA prognostic model that predicts ESCA survival and correlates with the tumor immune microenvironment. CONCLUSION: Based on PRGs features, we established a new ESCA hierarchical model. This model has important clinical implications for ESCA patients, both in terms of assessing prognosis and in terms of targeted and immunotherapy.

Comprehensive Curative Effect of Targeting PD-1 or Traditional Single-Agent Chemotherapy in Second-Line Therapy for Terminal or Metastatic Esophageal Cancer: A Systematic Review and Meta-Analysis.

The number of programmed cell death protein 1 (PD-1) inhibitors is gradually increasing; this study aimed to comprehensively and systematically evaluate the impact of PD-1 inhibitors as second-line therapy for terminal or metastatic esophageal cancer (EC) on patient survival and the occurrence of adverse events. Suitable randomized controlled trials (RCTs) were retrieved from PubMed, Web of Science, Embase, and Cochrane Library databases. Moreover, we searched for conference abstracts from the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) to compare the comprehensive curative effects of PD-1 inhibitors or single-agent therapy in terminal or metastatic EC. The primary outcome indicators were overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR). Treatment-related adverse events (TRAEs) were the secondary outcome indicators. We compared the previously mentioned indicators of the two treatment modalities using Stata software (version 12.0). We compared the long-term survival rates of both treatment groups and analyzed the possible factors affecting OS. We selected five RCTs with 2197 patients as study subjects. Compared with conventional single-agent chemotherapy, PD-1 inhibitors greatly improved the patients' OS (HR = 0.77, 95% CI 0.70-0.85, P < 0.001), but PFS (HR = 0.93, 95% CI 0.77-1.12, P=0.431) and DCR (RR = 0.93, 95% CI 0.71-1.22, P=0.609) were not greatly improved. Moreover, PD-1 inhibitors improved ORR (RR = 1.83, 95% CI 1.16-2.89, P=0.009) and decreased TRAEs (RR = 0.76, 95% CI 0.61-0.95, P < 0.001) and serious TRAEs (RR = 0.40, 95% CI 0.32-0.49, P < 0.001). Further analysis demonstrated that OS was affected by age, sex, region, smoking history, and the number of organ and lymph node metastases. Compared with the traditional single chemotherapy drugs, PD-1 inhibitors can achieve higher OS and ORR, fewer and more serious TRAEs, and better efficacy and safety for second-line therapy of terminal or metastatic EC.

GDF15 Contributes to Radioresistance by Mediating the EMT and Stemness of Breast Cancer Cells.

Radiotherapy is one of the conventional methods for the clinical treatment of breast cancer. However, radioresistance has an adverse effect on the prognosis of breast cancer patients after radiotherapy. In this study, using bioinformatic analysis of GSE59732 and GSE59733 datasets in the Gene Expression Omnibus (GEO) database together with the prognosis database of breast cancer patients after radiotherapy, the GDF15 gene was screened out to be related to the poor prognosis of breast cancer after radiotherapy. Compared with radiosensitive parental breast cancer cells, breast cancer cells with acquired radioresistance exhibited a high level of GDF15 expression and enhanced epithelial-to-mesenchymal transition (EMT) properties of migration and invasion, as well as obvious stem-like traits, including the increases of mammosphere formation ability, the proportion of stem cells (CD44+ CD24- cells), and the expressions of stem cell-related markers (SOX2, NANOG). Moreover, knockdown of GDF15 sensitized the radioresistance cells to irradiation and significantly inhibited their EMT and stem-like traits, indicating that GDF15 promoted the radioresistance of breast cancer by enhancing the properties of EMT and stemness. Conclusively, GDF15 may be applicable as a novel prognosis-related biomarker and a potential therapeutic target for breast cancer radiotherapy.

TIGAR knockdown radiosensitizes TrxR1-overexpressing glioma in vitro and in vivo via inhibiting Trx1 nuclear transport.

The up-regulation of thioredoxin reductase-1 (TrxR1) is detected in more than half of gliomas, which is significantly associated with increased malignancy grade and recurrence rate. The biological functions of NADPH-dependent TrxR1 are mainly associated with reduced thioredoxin-1 (Trx1) which plays critical roles in cellular redox signaling and tumour radio-resistance. Our previous work has proved that TP53 induced glycolysis and apoptosis regulator (TIGAR) knockdown could notably radiosensitize glioma cells. However, whether TrxR1-overexpressing glioma cells could be re-radiosensitized by TIGAR silence is still far from clear. In the present study, TrxR1 was stably over-expressed in U-87MG and T98G glioma cells. Both in vitro and in vivo data demonstrated that the radiosensitivity of glioma cells was considerably diminished by TrxR1 overexpression. TIGAR abrogation was able to radiosensitize TrxR1-overexpressing gliomas by inhibiting IR-induced Trx1 nuclear transport. Post-radiotherapy, TIGAR low-expression predicted significant longer survival time for animals suffering from TrxR1-overexpessing xenografts, which suggested that TIGAR abrogation might be a promising strategy for radiosensitizing TrxR1-overexpressing glial tumours.

Induction chemotherapy followed by concurrent chemoradiation and nimotuzumab for locoregionally advanced nasopharyngeal carcinoma: preliminary results from a phase II clinical trial.

Overexpression of epidermal growth factor receptor can be found in more than 80% of patients with locoregionally advanced nasopharyngeal carcinoma and is associated with shorter survival. In this work, we evaluated the feasibility of adding nimotuzumab to chemoradiation in locoregionally advanced nasopharyngeal carcinoma. Twenty-three patients with clinically staged T3-4 or any node-positive disease were enrolled. They were scheduled to receive one cycle of induction chemotherapy followed by intensity-modulated radiotherapy, weekly administration of nimotuzumab and concurrent chemotherapy. Results showed that all patients received a full course of radiotherapy, 19(82.6%)patients completed the scheduled neoadjuvant and concurrent chemotherapy, and 22(95.7%) patients received ≥6 weeks of nimotuzumab. During the period of concurrent chemoradiation and nimotuzumab, grade 3-4 toxicities occurred in 14(60.9%) patients: 8 (34.8%) had grade 3-4 oral mucositis, 6(26.1%) had grade 3 neutropenia, and 1(4.3%) had grade 3 dermatitis. No acne-like rash was observed. With a median follow-up of 24.1 months, the 2-year progression-free survival and overall survival were 83.5% and 95.0%, respectively. In conclusion, concurrent administration of chemoradiation and nimotuzumab was well-tolerated with good compliance. Preliminary clinical outcome data appear encouraging with favorable normal tissue toxicity results comparing with historical data of concurrent chemoradiation plus cetuximab.

TIGAR overexpression diminishes radiosensitivity of parotid gland fibroblast cells and inhibits IR-induced cell autophagy.

Our previous study proved that TP53-induced glycolysis and apoptosis regulator (TIGAR) abrogation is able to radiosensitize glioma cells. Whether TIGAR over-expression has radio-protective effect in human parotid gland cells is still unknown. In this study human parotid gland fibroblast Hs 917.T cells were transfected with pcDNA3.1-TIGAR, and clonogenic assay was performed to investigate the radiosensitivity of Hs 917.T cells over-expressing pcDNA3.1 or pcDNA3.1-TIGAR. Western blot was carried out to demonstrate the autophagy activity of cells being irradiated, and immunofluorescence assay was used to evaluate the DNA damage repair process of irradiated Hs 917.T cells. It was revealed that TIGAR over-expression could diminish the radiosensitivity of Hs 917.T cells, and the autophagy level induced by ionizing radiation (IR) was also decreased by TIGAR transfection. The mechanism might rely on TIGAR over-expression induced ROS scavenging and NADPH increasing. Using autophagy inhibitor, it was also elaborated that IR-induced autophagy in Hs 917.T cells was protective autophagy but not traumatic autophagy.

Fenofibrate enhances radiosensitivity of esophageal squamous cell carcinoma by suppressing hypoxia-inducible factor-1α expression.

Radiation therapy is widely used in esophageal squamous cell carcinoma (ESCC). Promoting radiation sensitivity is important. Recent studies have shown that fenofibrate can inhibit the growth of several cancer lines and hypoxia-inducible factor-1α (HIF-1α) expression in MCF-7 cells. However, few studies on the radiosensitive effect of fenofibrate on ESCCs under hypoxic condition have been conducted. In this study, we assessed the radiosensitive effects of fenofibrate on human ESCC cells. In vitro experiments showed the inhibition of cytotoxic effects after ionizing irradiation. We measured cell viability and clonogenic survival rate. Flow cytometry showed that fenofibrate pretreatment promoted apoptosis. The in vivo data also suggest that fenofibrate had radiosensitizing effects in ECA-109 cells xenografted into nude mice. Western blot and immunohistochemical analyses revealed that the HIF-1α and vascular endothelial growth factor (VEGF) protein content decreased by fenofibrate. Thus, the inhibition of HIF-1α and VEGF expression in ESCC cells contributed to the radiosensitive effect. These data suggest that fenofibrate may be a potential radiosensitive drug.

Adenovirus-mediated coexpression of DCX and SPARC radiosensitizes human malignant glioma cells.

This study is designed to examine the radiosensitizing effects of coexpression of doublecortin (DCX) and secreted protein and rich in cysteine (SPARC). Previously, we showed that downregulation of SPARC by small interfering RNA increased radioresistance of U-87MG glioma cells. Therefore, overexpression of SPARC might increase radiosensitivity of glioma cells. But SPARC has been shown to promote glioma cell invasion both in vitro and vivo. In order to radiosensitize glioma cells without stimulating invasion, we chose DCX, which is a well-characterized anti-tumor gene, to coexpress with SPARC. An adenovirus-mediated double gene expression system was constructed and applied to U251 and A172 glioma cell lines. Our data showed that coexpression of DCX and SPARC collaboratively diminished radioresistance of glioma cells, interfered with cell cycle turnover and increased irradiation-induced apoptosis. In addition, transwell assay revealed that coexpression was able to counteract the invasion-promoting effects of SPARC, and even inhibited intrinsic invasion, evidenced by less invading cells in double gene overexpressed group than that of control adenovirus-treated group. In conclusion, genetic engineering combining two or more genes might be a more effective method to overcome radioresistance of glioma cells.