Mutational landscape of homologous recombination-related genes in small-cell lung cancer.

BACKGROUND: Homologous recombination deficiency (HRD) is a well-known biomarker which could predict poly-ADP ribose polymerase 1 (PARP) inhibitor and platinum drug response. As an aggressive cancer, small-cell lung cancer (SCLC) is sensitive to platinum drugs, but relapse occurs rapidly. Herein, we aim to illustrate the genomic alteration patterns of homologous recombination repair (HRR)-related genes in a Chinese SCLC cohort and further analyze the relationship among HRR gene mutations and known biomarkers of immune checkpoint inhibitor (ICI) response, including tumor mutation burden (TMB) and programmed cell death-ligand 1 (PD-L1) expression. METHODS: Next-generation sequencing (NGS)-based target capture sequencing of 543 cancer-related genes was performed to analyze the genomic profiles of 133 Chinese SCLC patients, and TMB was calculated. PD-L1 expression was evaluated in 90 out of 133 patients using the SP142 PD-L1 immunohistochemistry assay. RESULTS: Among the 133 patients with SCLC, 47 (35.3%) had HRR gene mutations. ATM (8.3%) was the most frequently mutated HRR gene in the cohort, followed by NBN (4.5%). Pathogenic somatic and germline mutations of HRR genes were identified in 11 (23.4%) and 4 (8.5%) patients, respectively. HRR gene mutations cooccurred with KMT2D gene mutations. There were several differences in genomic alterations between patients with HRR gene mutations (HRR-Mut) and without HRR mutations (HRR-WT). The results revealed that TP53 and RB1 were commonly mutated genes in both groups. Mutations in the KMT2D gene and genes in the RTK-RAS pathway occurred more frequently in the HRR-Mut group. Furthermore, we found that mutations in HRR genes were associated with high TMB (Wilcoxon, p = 0.048), but there was no correlation of HRR gene mutation status with PD-L1 expression. CONCLUSIONS: We exhaustively describe the genomic alteration profile of Chinese SCLC patients and provide further evidence that HRR gene mutations are prevalent in SCLC patients.

Immune response to fused core protein of hepatitis C virus and truncated tetanus toxin peptides in mice.

Because no vaccine or effective therapy is available, thousands of people with HCV have died in recent years. Cytotoxic T lymphocytes (CTLs) play a critical role in the host cellular immune response against HCV. CTL epitopes in HCV core protein have been identified and used in vaccine development. T helper epitopes could promote cytokine secretion and antibody production to fight HCV. Tetanus toxin, an immunogen with many T helper epitopes, was once used in HBV therapeutic vaccine design. Here, eukaryotic and prokaryotic expression vectors were constructed to express truncated fragments of tetanus toxin and core genes of HCV. HLAA2.1 transgenic mice were inoculated with a recombinant plasmid vehicle with these two heterogenic gene fragments, and this augmented the titres of antibody against HCV. Antigen-specific lymphocyte proliferation, Th1 and Th2 cytokine levels and the number of lysed cells were markedly increased in the combined immunization group compared to controls. These findings provide new insights into a potential role for T helper epitopes from tetanus toxin combined with protein from the HCV core gene, which has numerous CTL epitopes. This design strategy may aid in the development of new vaccines against HCV.

[Expression of apoptosis related protein in transforming growth factors-beta signaling pathway and its effects on the cell apoptosis in the lung tissues after acute pulmonary embolism].

OBJECTIVE: To study the expression changes in apoptosis related protein in transforming growth factors-beta signaling pathway (ARTS) in the lung tissues in a rat acute pulmonary embolism (APE) model and its effects on cell apoptosis. METHODS: A rat APE model was reproduced. Samples of lung tissues were harvested at time points of 1, 8, 24 and 48 hours after APE. Healthy rats were used as control. The changes in mRNA level of ARTS were identified by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), and the changes in its protein level, and also Bcl-2, Bcl-xL, XIAP and H2Ax proteins, which were related with ARTS-mediated cell apoptosis, were determined by Western blotting. Immunohistochemical method was employed to study the distribution and expression changes in ARTS in the lung tissue before and after APE. Apoptotic cells in lung tissue sections were identified by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) method. RESULTS: At different time points, the mRNA levels and the protein levels of ARTS significantly increased in the lung tissues of rats with APE at 1 hour and 48 hours (P<0.05 or P<0.01). The immunohistochemical study showed that ARTS had low expression levels and could not be detected in the normal lung tissue, but it was up-regulated obviously at 48 hours after APE, mainly expressed in the bronchial epithelium and the lung alveolar epithelium. Apoptotic cells could be observed in the lung tissue by TUNEL after APE and at the same time when the lung tissue cells exhibited lower levels of the anti-apoptotic proteins Bcl-2, Bcl-xL, and XIAP, as compared with controls. Apoptosis level (as evaluated by H2Ax, apoptotic marker staining) in the lung tissue cells was obviously raised compared with controls (P<0.05 or P<0.01). CONCLUSION: The expression of ARTS is up-regulated after APE, and ARTS-mediated apoptosis plays an important role in the cell apoptosis of lung tissue.