Overexpression of COX7A1 Promotes the Resistance of Gastric Cancer to Oxaliplatin and Weakens the Efficacy of Immunotherapy.

Gastric cancer (GC) is one of the most common clinical malignant tumors worldwide, with high morbidity and mortality. Presently, the overall response rate to immunotherapy is low, and current methods for predicting the prognosis of GC are not optimal. Therefore, novel biomarkers with accuracy, efficiency, stability, performance ratio and wide clinical application are needed. Based on public data sets, the Chemotherapy Cohort and the Immunotherapy Cohort from Sun Yat-sen University Cancer Center, a series of bioinformatics analyses, such as differential expression analysis, survival analysis, drug sensitivity prediction, enrichment analysis, tumor immune dysfunction and exclusion (TIDE) analysis, single-sample gene set enrichment analysis (ssGSEA), stemness index calculation, immune cell infiltration analysis, were performed for screening and preliminary exploration. Immunohistochemical staining and in vitro experiments were performed for further verification. Overexpression of COX7A1 promoted the resistance of GC cells to Oxaliplatin. COX7A1 may induce immune escape by regulating the number of fibroblasts and their cellular communication with immune cells. In summary, measuring the expression levels of COX7A1 in the clinic may be useful to predict the prognosis of GC patients, the degree of chemotherapy resistance and the efficacy of immunotherapy.

Construction of a gene model related to the prognosis of patients with gastric cancer receiving immunotherapy and exploration of COX7A1 gene function.

BACKGROUND: GC is a highly heterogeneous tumor with different responses to immunotherapy, and the positive response depends on the unique interaction between the tumor and the tumor microenvironment (TME). However, the currently available methods for prognostic prediction are not satisfactory. Therefore, this study aims to construct a novel model that integrates relevant gene sets to predict the clinical efficacy of immunotherapy and the prognosis of GC patients based on machine learning. METHODS: Seven GC datasets were collected from the Gene Expression Omnibus (GEO) database, The Cancer Genome Atlas (TCGA) database and literature sources. Based on the immunotherapy cohort, we first obtained a list of immunotherapy related genes through differential expression analysis. Then, Cox regression analysis was applied to divide these genes with prognostic significancy into protective and risky types. Then, the Single Sample Gene Set Enrichment Analysis (ssGSEA) algorithm was used to score the two categories of gene sets separately, and the scores differences between the two gene sets were used as the basis for constructing the prognostic model. Subsequently, Weighted Correlation Network Analysis (WGCNA) and Cytoscape were applied to further screen the gene sets of the constructed model, and finally COX7A1 was selected for the exploration and prediction of the relationship between the clinical efficacy of immunotherapy for GC. The correlation between COX7A1 and immune cell infiltration, drug sensitivity scoring, and immunohistochemical staining were performed to initially understand the potential role of COX7A1 in the development and progression of GC. Finally, the differential expression of COX7A1 was verified in those GC patients receiving immunotherapy. RESULTS: First, 47 protective genes and 408 risky genes were obtained, and the ssGSEA algorithm was applied for model construction, showing good prognostic discrimination ability. In addition, the patients with high model scores showed higher TMB and MSI levels, and lower tumor heterogeneity scores. Then, it is found that the COX7A1 expressions in GC tissues were significantly lower than those in their corresponding paracancerous tissues. Meanwhile, the patients with high COX7A1 expression showed higher probability of cancer invasion, worse clinical efficacy of immunotherapy, worse overall survival (OS) and worse disease-free survival (DFS). CONCLUSIONS: The ssGSEA score we constructed can serve as a biomarker for GC patients and provide important guidance for individualized treatment. In addition, the COX7A1 gene can accurately distinguish the prognosis of GC patients and predict the clinical efficacy of immunotherapy for GC patients.

Chemoradiotherapy in combination with radical surgery is associated with better outcome in cervical cancer patients.

OBJECTIVES: To retrospectively assess the influence of radical surgery following concurrent chemoradiotherapy (CCRT) on outcomes in cervical cancer (CC) patients. METHODS: Patients diagnosed with cervical squamous cell carcinoma or adenocarcinoma (FIGO stages IB2 to IIB) at the Yinbin Second People's Hospital between September 2008 and September 2013, were included in this study. Patients were classified into 2 groups based on the treatment received: surgery group (CCRT plus radical surgery) and non-surgery groups (CCRT only). In addition to clinical information, inter-group differences with respect to local control rate (LCR), local recurrence rate (LRR), metastasis rate, overall survival (OS), progress free survival(PFS) and complications were assessed. RESULTS: A total of 314 patients were included in the analysis. Parametrial invasion, pelvic lymph node metastasis, tumor diameter > 4 cm and presence of residual disease were risk factors for recurrence in the non-surgery group. In patients with risk factors, radical surgery significantly improved their clinical outcome. The 3-year/5-year LCR in the surgery and non-surgery groups was 88.3%/87.4% and 82.3%/77.5%, respectively (P = 0.04). The 3-year/5-year OS rate in the two groups was 87.1%/81.7% and 72.8%/67.3%, respectively (P = 0.001). The 3-year/5-year LRR in the two groups were 11.7%/12.6% and 17.7%/22.5%, respectively (P = 0.04). The metastasis rates in the two groups were 19.9% and 24.8%, respectively (P = 0.09). CONCLUSIONS: Surgery following CCRT could improve overall survival and progressfree survival. Radical surgery following CCRT appears to confer significant benefits including an increase in LCRs and decrease in LRR in CC patients with risk factors.

[The bio-effects of high single-dose radiation on xenografts of Lewis lung carcinoma].

OBJECTIVE: To investigate the bio-effects of high single-dose radiation on xenografts of Lewis lung carcinoma. METHODS: Female 8-week-old C57 mice bearing 4-6 mm diameter Lewis lung carcinoma tumors in the hind legs were divided into 3 groups, control group (0 Gy), high single-dose group (12 Gy/one fraction/day) and routine radiation group (22 Gy/11 fraction/15 d). The mean biological effective dose (BED) of both radiation groups was 26.4 Gy. Changes in hypoxia, DNA damage and cell cycle of the tumor cells at 1, 3, 8, 15 and 21 d after first irradiation was assessed by immunofluorescence and flow-cytometry and the tumor growth curve was also made. RESULTS: Compared to the fractionated treatment, the tumor growth was delayed after single dose irradiation. The percent of hypoxic cells after single dose radiation was lower than fractioned irradiation at 3, 8, 15 d after first radiation. The foci of gamma-H2AX showed that the single dose caused heavier DNA damages than fractioned irradiation at 1, 3 d after first radiation. The decline of G0/G1 percentage and increase of G2/M percentage of cells was found in both radiation schedules, but the G2/M percentage after single dose radiation was higher. CONCLUSION: In the C57 mice bearing Lewis lung carcinoma, the high single-dose regimen inhibits the tumor growth more than fractioned irradiation. We hypothesized that conversion of high single-dose to BED using the LQ formalism under estimated the in vivo effect of hypofractionated radiation.

Ablative hypofractionated radiotherapy normalizes tumor vasculature in lewis lung carcinoma mice model.

Ablative hypofractionated radiotherapy (HFRT) significantly improves the overall survival of inoperable non-small cell lung cancer (NSCLC) patients compared with conventional radiation therapy. However, the radiobiological mechanisms of ablative HFRT remain largely unknown. The purpose of this study was to investigate the dynamic changes of tumor vessels and perfusion during and after ablative hypofractionated radiotherapy. Lewis lung carcinoma-bearing mice were treated with sham (control) and ablative hypofractionated radiotherapy of 12 Gy in 1 fraction (12 Gy/1F) and 36 Gy in 3 fractions (36 Gy/3F). Tumor microvessel density (MVD), morphology and function were examined at different times after irradiation. The results showed that, compared to the controls the MVD and hypoxia in ablative HFRT groups decreased, which were accompanied by an increase in the number of pericytes and their coverage of vessels. Functional tests revealed that tumor hypoxia and perfusion were improved, especially in the 36 Gy/3F group. Our results revealed that ablative hypofractionated radiotherapy not only repressed MVD and hypoxia, but also increased the vascular perfusion and the number of pericyte-covered vessels, suggesting that ablative HFRT normalized the tumor vasculature.

[Detection of epidermal growth factor receptor gene mutation in non-small cell lung cancer by allele-specific oligonucleotide-PCR and bi-loop probe specific primer quantitative PCR].

OBJECTIVE: To compare the detection sensitivity of epidermal growth factor receptor (EGFR) mutations between allele specific oligonucleotide PCR (ASO-PCR) and bi-loop probe and specific primer quantitative PCR (BPSP-qPCR). METHODS: A total of 96 non-small cell lung cancer specimens were selected from West China Hospital from September 2009 to December 2010. ASO-PCR was developed to detect the presence of classical EGFR mutations. A total 39 available specimens were also tested by BPSP-qPCR. RESULTS: EGFR mutation detection rate was 30.2% (26/96) by ASO-PCR. The mutation rate was higher in female than in male patients [45.5% (20/44) vs. 17.3% (9/52), P = 0.003], non-smokers than smokers [44.1% (26/59) vs. 8.1% (3/37), P < 0.001] and adenocarcinomas than other subtypes of lung cancer [37.0% (27/73) vs. 8.7% (2/23), P = 0.01]. Among mutation negative cases by ASO-PCR, BPSP-qPCR increased the rate of detection of 19-del and L858R mutation by 10.3% (4/39) in adenocarcinomas and non-smoking subset. Overall, the mutation detection rate of BPSP-qPCR was higher than that of ASO-PCR [66.7% (26/39) vs. 41.0% (16/39), P = 0.02]. CONCLUSION: BPSP-qPCR has a better detection sensitivity than that of ASO-PCR.

[Detection of epidermal growth factor receptor gene mutations in non-small cell lung cancer using bi-loop probe specific primer quantitative PCR].

OBJECTIVE: To investigate the sensitivity of bi-loop probe and specific primer quantitative PCR (BPSP-qPCR) in the detection of epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC). METHODS: BPSP-qPCR was employed to examine the presence of mutations of EFGR exon 19 through 21. Correlation of the mutations with clinicopathological characteristics and types of tumor samples were performed. RESULTS: In the cohort of 265 specimens, 30.2% (80/265) mutations were found to be 19-del and/or L858R. Females (39.7%, 31/78), non-smokers (41.0%, 43/105) and adenocarcinoma patients (37.8%, 51/135) had a higher mutation rate (P<0.05) among 184 patients whose profiles were available. T790M combined with 19-del and/or L858R accounted for 3.3% (6/184) of the mutations. Male metastatic tumors (29.6%, 8/27), pleural fluids of females (42.9%, 9/21) and non-smokers (40.7%, 11/27) were found to have higher percentage of 19-del and/or L858R mutations, in contrast, no mutations were found in the metastatic lesions of non-adenocarcinoma patients (P>0.05). CONCLUSIONS: BPSP-qPCR is a robust method in detection of EGFR mutations with high consistency and sensitivity. The difference of EGFR mutations in primary tumors, metastatic lesions and pleural fluids suggests that EGFR tyrosine kinase inhibitors (EGFR-TKI) treatment may have variable treatment effects depending on the tumor sites.