Characterization of stemness features and construction of a stemness subtype classifier to predict survival and treatment responses in lung squamous cell carcinoma.

BACKGROUND: Cancer stemness has been proven to affect tumorigenesis, metastasis, and drug resistance in various cancers, including lung squamous cell carcinoma (LUSC). We intended to develop a clinically applicable stemness subtype classifier that could assist physicians in predicting patient prognosis and treatment response. METHODS: This study collected RNA-seq data from TCGA and GEO databases to calculate transcriptional stemness indices (mRNAsi) using the one-class logistic regression machine learning algorithm. Unsupervised consensus clustering was conducted to identify a stemness-based classification. Immune infiltration analysis (ESTIMATE and ssGSEA algorithms) methods were used to investigate the immune infiltration status of different subtypes. Tumor Immune Dysfunction and Exclusion (TIDE) and Immunophenotype Score (IPS) were used to evaluate the immunotherapy response. The pRRophetic algorithm was used to estimate the efficiency of chemotherapeutic and targeted agents. Two machine learning algorithms (LASSO and RF) and multivariate logistic regression analysis were performed to construct a novel stemness-related classifier. RESULTS: We observed that patients in the high-mRNAsi group had a better prognosis than those in the low-mRNAsi group. Next, we identified 190 stemness-related differentially expressed genes (DEGs) that could categorize LUSC patients into two stemness subtypes. Patients in the stemness subtype B group with higher mRNAsi scores exhibited better overall survival (OS) than those in the stemness subtype A group. Immunotherapy prediction demonstrated that stemness subtype A has a better response to immune checkpoint inhibitors (ICIs). Furthermore, the drug response prediction indicated that stemness subtype A had a better response to chemotherapy but was more resistant to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). Finally, we constructed a nine-gene-based classifier to predict patients' stemness subtype and validated it in independent GEO validation sets. The expression levels of these genes were also validated in clinical tumor specimens. CONCLUSION: The stemness-related classifier could serve as a potential prognostic and treatment predictor and assist physicians in selecting effective treatment strategies for patients with LUSC in clinical practice.

Factors affecting the scientific research ability and the corresponding countermeasures in clinical postgraduates.

BACKGROUND: Scientific research ability (SRA) is very important for clinical postgraduates. However, the factors affecting students' SRA are constantly changing with the development of medicine. The aim of this study was to investigate the current situation of SRA in clinical postgraduates and exploring the potential factors and the corresponding countermeasures under the background of new medical science. METHODS: A total of 133 postgraduates (first- or second-year) were investigated by questionnaire in the Second Affiliated Hospital of Fujian Medical University. All results were analyzed by R software. RESULTS: In terms of the SRA, academic-degree postgraduate students (ADPSs) were significantly better than professional-degree postgraduate students (PDPSs) (P = 0.001), the students with scientific research interest were remarkably better than those without scientific research interest (P = 0.004), the students who mastered statistical analysis methods were more prominent than those who did not (P = 0.007), the students with paper-writing skills were obviously superior to those without it (P = 0.003), and the second-year students were notably better than the first-year students (P = 0.003). Stratified analysis by the above factors except the degree type showed no significant difference in the first-year postgraduates. In the second-year postgraduates, the ADPSs were remarkably superior to the PDPSs (P = 0.002), the students with scientific research interest were obviously better than those without scientific research interest (P = 0.014), the students with more time investment in scientific research were more prominent than those with less time investment in scientific research (P = 0.025), the students with paper-writing skills were notably superior to those without it (P = 0.031), and the students with plotting ability were better than those without it (P = 0.013). CONCLUSION: The important factors affecting the SRA of clinical postgraduates include the degree type, the grade of student, scientific research interest, time investment in scientific research, statistical analysis methods, paper-writing skills, plotting ability. In short, earlier systematic SRA training contributes to the improvement of SRA in clinical postgraduates, especially in PDPSs.

B7H4 expression in tumor cells impairs CD8 T cell responses and tumor immunity.

B7 homolog 4 (B7H4) is considered a negative regulator of immune responses, but the immunoregulatory role of B7H4 in the tumor microenvironment is not clear. Here, we assessed B7H4 expression cell types in human breast cancer tissues and addressed its potential mechanisms in the CD8 T cell immune response. The results from flow cytometry and immunohistochemistry demonstrated that B7H4 was highly expressed in 26 out of 30 (86.7%) breast invasive ductal carcinomas, and B7H4 surface expression on tumor cells was inversely correlated with CD8 T lymphocytes infiltration (p < 0.0001). In vivo, B7H4-overexpressing tumor cells showed enhanced tumor growth in immunocompetent mice with impaired CD8 T cell infiltration of the tumor. Further investigation showed that activation and expansion of CD8 T cells within the lymph nodes were suppressed in B7H4-overexpessing tumor-bearing mice. An in vitro killing assay showed that the cytotoxicity of CD8 T cells was inhibited in B7H4-overexpressing tumor cells. These findings suggest that B7H4 in tumor cells is a negative regulator of CD8 T cell activation, expansion and cytotoxicity, indicating that tumor cell-associated B7H4 might be a target for T cell-based cancer immunotherapy.

Iron blocks autophagic flux and induces autophagosomes accumulation in microglia.

Iron is an essential dietary micronutrient for maintaining physiological homeostasis. However, disruption of cerebral iron regulation with the accumulation of iron in different brain structures appears to have a role in the pathogenesis of various neurodegenerative disorders. Studies have reported that autophagy induction could potentially mitigate progression in neurodegenerative diseases with iron deposition, but the relationship between autophagy and iron remains poorly understood. Meanwhile, abnormal autophagy in microglia is closely related to the occurrence of neurodegenerative diseases. Therefore, the effect of iron on microglia autophagy needs to be elaborated. In the present study, we found that iron induces autophagosome accumulation but inhibits its initiation in an Akt-mTOR pathway independent manner. Meanwhile, it caused autophagy flux defects and dysfunction of lysosomes. We also found that iron overload reduced the expression of Rab7, which is an essential protein for the fusion of autophagosomes and lysosomes. These results suggest that iron induces the accumulation of autophagosome in microglia and disrupts the autophagic flux in late stage of autophagy. Therefore, our work provides new insights into the molecular mechanisms of iron neurotoxicity.

Evaluating the tumor immune profile based on a three-gene prognostic risk model in HER2 positive breast cancer.

To date, there have not been great breakthroughs in immunotherapy for HER2 positive breast cancer (HPBC). This study aimed to build a risk model that might contribute to predicting prognosis and discriminating the immune landscape in patients with HPBC. We analyzed the tumor immune profile of HPBC patients from the TCGA using the ESTIMATE algorithm. Thirty survival-related differentially expressed genes were selected according to the ImmuneScore and StromalScore. A prognostic risk model consisting of PTGDR, PNOC and CCL23 was established by LASSO analysis, and all patients were classified into the high- and low-risk score groups according to the risk scores. Subsequently, the risk model was proven to be efficient and reliable. Immune related pathways were the dominantly enriched category. ssGSEA showed stronger immune infiltration in the low-risk score group, including the infiltration of TILs, CD8 T cells, NK cells, DCs, and so on. Moreover, we found that the expression of immune checkpoint genes, including PD-L1, CTLA-4, TIGIT, TIM-3 and LAG-3, was significantly upregulated in the low-risk score group. All the results were validated with corresponding data from the GEO database. In summary, our investigation indicated that the risk model composed of PTGDR, PNOC and CCL23 has potential to predict prognosis and evaluate the tumor immune microenvironment in HPBC patients. More importantly, HPBC patients with a low-risk scores are likely to benefit from immune treatment.

T cell recruitment triggered by optimal dose platinum compounds contributes to the therapeutic efficacy of sequential PD-1 blockade in a mouse model of colon cancer.

Recently, the combination of platinum chemotherapy with PD-1/PD-L1 pathway blockades has shown synergistic efficacy in a few clinical trials. However, the exact mechanisms and the optimized sequence of such combinations are not fully clear. In this study, we combined different doses of platinum agents (cisplatin or oxaliplatin) with sequential therapy of PD-1 blockade therapy (anti-PD-1 antibody or anti-PD-L1 antibody) to treat established MC38 murine colon tumors. Although 10 mg/kg platinum (cisplatin or oxaliplatin) showed no significant effect on tumor growth, its combination with sequential anti-PD-1 antibody administration caused complete tumor remission in 80-100% mice. The synergic therapeutic efficacy was found to be associated with more effector and less exhausted CD8 T cell infiltration in the tumor sites. Platinum chemotherapy is generally considered immunosuppressive, with lymphopenia and neutropenia being common side effects. However, our data showed that high-dose (20 mg/kg) platinum treatment induced lymphopenia in MC38 tumor-bearing mice, and low-dose (10 mg/kg) treatment augmented the T cell response with an increased number of peripheral T cells. Notably, increased numbers of PD-1 positive CD8 T cells were found in draining lymph nodes, peripheral blood and tumor tissues three days after 10 mg/kg oxaliplatin treatment, and increased numbers of CD8 T cells and apoptotic tumor cells were detected at the edge of tumor tissues. Further investigation showed that the death of tumor cells induced by platinum compounds promoted T cell activation. Moreover, increased expression of T cell-attracting chemokines (CXCL9, CXCL10 and CCL5) was detected in MC38 cells after platinum treatment. These data indicated that the optimal dose of platinum chemotherapy could trigger T cell activation and recruitment into tumors, and sequential PD-1 blockade could prevent newly arriving T cell from becoming exhausted in tumor sites. These findings highlight the importance of optimizing the dose and timing of platinum chemotherapy combined with PD-1 blockade and provide an indication for the improvement of combined therapies in clinical trials.

Mcl-1 inhibitor suppresses tumor growth of esophageal squamous cell carcinoma in a mouse model.

Esophageal squamous cell carcinoma (ESCC) has a high morbidity in China, accounting for 90% of all esophageal carcinoma cases. Hence, identifying drug targets for prevention and treatment of ESCC is essential. Due to its critical role in the regulation of cell apoptosis, Mcl-1 holds great potential as a target for treatment against ESCC. In current study, we used a 4-nitroquinoline-1-oxide (4-NQO)-induced ESCC mouse model of test whether A-1210477, a Mcl-1 small molecular inhibitor, could repress ESCC development. We showed that A-1210477 treatment decreased ESCC formation and animal weight loss in a dose dependent manner. We detected decreased cellular proliferation in A-1210477-treated ESCC tissue by Ki67 expression. Moreover, A-1210477 treatment increased the number of apoptotic cells in ESCC tissues. Our study clearly demonstrates the contribution of Mcl-1 to ESCC development through promoting cell proliferation and inhibition of apoptosis, and provides a strong evidence for further evaluation of A-1210477 for treating ESCC.

Genetic variations of TLR5 gene interacted with Helicobacter pylori infection among carcinogenesis of gastric cancer.

Gastric cancer (GC) ranks the second prevalent cancer type and the second cancer-related death in China. However, the precise mechanisms of GC development remain poorly understood. Chronic infection with Helicobacter pylori is the strongest identified risk factor for GC. Toll-like receptor (TLR) genes, which play critical roles in Helicobacter pylori induced chronic inflammation, may also be implicated in GC susceptibility. TLR5 signaling deficiency could deregulate a cascade of inflammatory events. In current study, we systematically evaluated genetic variations of TLR5, and their interaction with Helicobacter pylori infection among carcinogenesis of gastric cancer, using a large case-controls study among Chinese population. Minor alleles of three SNPS, including rs5744174 (P = 0.001), rs1640827 (P = 0.005), and rs17163737 (P = 0.004), were significantly associated with increased GC risk (OR ranged from 1.20-1.24). Significant interactions with Helicobacter pylori infection were also identified for rs1640827 (P for interaction = 0.009) and rs17163737 (P for interaction = 0.006). These findings suggest that genetic variants in TLR5 may modify the role of Helicobacter pylori infection in the process of causing GC.