SARS-CoV-2 receptor ACE2 identifies immuno-hot tumors in breast cancer

Angiotensin-converting enzyme 2 (ACE2) is known as a host cell receptor for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which is identified to be dysregulated in multiple tumors. Although the characterization of abnormal ACE2 expression in malignancies has been preliminarily explored, in-depth analysis of ACE2 in breast cancer (BRCA) has not been elucidated. A systematic pan-cancer analysis was conducted to assess the expression pattern and immunological role of ACE2 based on RNA-sequencing (RNA-seq) data downloaded from The Cancer Genome Atlas (TCGA). Next, correlations between ACE2 expression immunological characteristics in the BRCA tumor microenvironment (TME) were evaluated. Also, the role of ACE2 in predicting the clinical features and the response to therapeutic options in BRCA was estimated. These findings were subsequently validated in another public transcriptomic cohort as well as a recruited cohort. ACE2 was lowly expressed in most cancers compared with adjacent tissues. ACE2 was positively correlated with immunomodulators, tumor-infiltrating immune cells (TIICs), cancer immunity cycles, immune checkpoints, and tumor mutation burden (TMB). Besides, high ACE2 levels indicated the triple-negative breast cancer (TNBC) subtype of BRCA, lower response to endocrine therapy and higher response to chemotherapy, anti-ERBB therapy, antiangiogenic therapy and immunotherapy. To sum up, ACE2 correlates with an inflamed TME and identifies immuno-hot tumors, which may be used as an auxiliary biomarker for the identification of immunological characteristics in BRCA.

Systemic analysis of tissue cells potentially vulnerable to SARS-CoV-2 infection by the protein-proofed single-cell RNA profiling of ACE2, TMPRSS2 and Furin proteases

Single-cell RNA profiling of ACE2, the SARS-CoV-2 receptor, had proposed multiple tissue cells as the potential targets of SARS-CoV-2, the novel coronavirus causing the COVID-19 pandemic. However, most were not echoed by the patients clinical manifestations, largely due to the lack of protein expression information of ACE2 and co-factors. Here, we incorporated the protein information to analyse the expression of ACE2, together with TMPRSS2 and Furin, two proteases assisting SARS-CoV-2 infection, at single cell level in situ, which we called protein-proofed single-cell RNA (pscRNA) profiling. Systemic analysis across 36 tissues revealed a rank list of candidate cells potentially vulnerable to SARS-CoV-2. The top targets are lung AT2 cells and macrophages, then cardiomyocytes and adrenal gland stromal cells, followed by stromal cells in testis, ovary and thyroid. Whereas, the polarized kidney proximal tubule cells, liver cholangiocytes and intestinal enterocytes are less likely to be the primary SARS-CoV-2 targets as ACE2 localizes at the apical region of cells, where the viruses may not readily reach. Actually, the stomach may constitute a physical barrier against SARS-CoV-2 as the acidic environment in normal stomach (pH < 2.0) could completely inactivate SARS-CoV-2 pseudo-viruses. These findings are in concert with the clinical characteristics of prominent lung symptoms, frequent heart injury, and uncommon intestinal symptoms and acute kidney injury. Together, we provide a comprehensive view on the potential SARS-CoV-2 targets by pscRNA profiling, and propose that, in addition to acute respiratory distress syndrome, attentions should also be paid to the potential injuries in cardiovascular, endocrine and reproductive systems during the treatment of COVID-19 patients.

SMAR1 promotes immune escape of Tri-negative Breast Cancer through a mechanism involving T-bet/PD-1 Axis.

This study was aimed at investigating the specific molecular mechanisms involved in the regulation of immune escape of triple-negative breast cancer (TNBC) by SMRI, so as to provide a new clinical treatment target for the disease. Mouse original 4T1 breast cancer cells were inoculated subcutaneously in BALB/C to establish TNBC mouse model. CD8+T cells with immunological effects were selected from mouse thymus glands for primary culture. The CD8+positive T cells were infected with lentivirus interference vectors, and the proliferation of CD8+ T cells were determined by trypan blue staining and flow cytometry. CD8+T cells and 4T1 cells were cultured together so as to determine the cytotoxic effects of SMAR1-downregulated CD8+ T cells on tumor cells and the expression of cytokines (IFN-γ, TNF-α, IL-2, IL-4 and IL-6). The expressions of SMAR1, T-bet and PD-1 were assayed by Western blot. SMAR1-downregulated CD8+T cells were injected into 4T1 tumor-bearing mice through the caudal vein, and the growth of tumor in mice was monitored. Following the infection of CD8+T cells with SMAR1-downregulated lentiviral system, cell apoptosis level was decreased significantly (control vs. sh-SMAR1: 32.23 ± 12.4 % vs. 18.28 ± 8.93 %, p < 0.05). Results from trypan blue staining experiments showed that the proliferation of CD8+ T cells in the SMAR1-downregulated group was significantly increased; SMAR1-downregulated CD8+ T cells promoted the production of IFN-γ, TNF-α, IL-2, IL-4 and IL-6 in 4T1 breast cancer cells (p < 0.05). Western blot showed that SMAR1 down-regulation led to significant upregulation of T-bet, while PD-1 was downregulated, when compared to the control group (p < 0.05). The downregulation of SMAR1 was associated with significant reduction in tumor size in mice (p < 0.05). SMAR1 downregulation enhances the tumor killing effect of CD8+T cells by activating T-bet and down-regulating PD-1.

Bone marrow mesenchymal stem cells modulated the inflammatory response by regulating the expression of IL-4 and RAGE products in the rats with MODS / 中华危重病急救医学

Objective To investigate the underlying mechanism of bone marrow mesenchymal stem cells (BMSC) modulating the inflammatory response during the multiple organ dysfunction syndrome (MODS), especially the expression of inflammatory cytokines, which will provide new theoretical and experimental basis of MODS in clinic. Methods BMSC of Sprague-Dawley (SD) rat (female, 4 weeks) was extracted and cultivated, and the 4th passage were used in experimental study. According to the random number table, 60 female SD rats were divided into three groups (n = 20 per group): sham group, MODS group, BMSC group. MODS model in rats was induced by lipopolysaccaride (LPS, 1 mg/kg) via femoral vein injection. Sham group was injected with the sterile phosphate buffer saline (PBS) in the same volume. BMSC group, in which BMSC infusion was started at 2 hours after 0.5 mL LPS stimulation (1×106/cells) through the tail vein. The survival rate was observed after 72 hours in each group. Abdominal aortic blood was collected for routine blood and biochemical examination at 72 hours after operation. Protein microarray was used to detect the related 34 inflammatory cytokines. Signal ratio was defined as the differentially expressed factors when it was more than 2.0 or less than 0.5. And enzyme linked immunosorbent assay (ELISA) was be applied to validate the significant inflammation factor. Meanwhile, the heart, kidney, intestine tissue was harvested, then their pathological changes were observed by hematoxylin eosin (HE) staining.Results 20, 12, 16 rats lived in sham group, MODS group and BMSC group respectively at 72 hours after operation. Compared with the sham group, the indicators (routine blood, liver and kidney function, myocardial enzyme) were apparently unusual, and the heart, kidney, intestine tissue were injured obviously in the MODS group. After BMSC administration, the organ function was improved and tissue damaged was alleviated significantly. Protein microarray showed that interleukin-4 (IL-4) and receptor for advanced glycation end products (RAGE) were significantly different in 34 goal cytokines. The signal ratio change of IL-4 was 0.397, 1.124, 2.826 respectively, and the signal ratio of RAGE was 6.197, 1.552, 0.250, respectively in MODS/sham group, BMSC/sham group, BMSC/MODS group. ELISA validated the result that the expression level of IL-4 decreased significantly (ng/L:3.59±1.21 vs. 29.10±5.78) and the expression level of RAGE increased significantly (ng/L: 1.09±0.04 vs. 0.11±0.03) in MODS group as compared with sham group (bothP < 0.05). Compared with the MODS group, the level of IL-4 was obviously higher than that in BMSC group (ng/L: 9.59±2.21 vs. 3.59±1.21,P < 0.01), and RAGE decreased significantly (ng/L: 0.29±0.07 vs. 1.09±0.04,P < 0.05).Conclusions BMSC administration can regulate the expression of IL-4 and RAGE in the rats subjected to MODS. Moreover, BMSC can promote the restoration of tissue and organ function, thus improve the survival rate. BMSC may be the target in cell therapy for the inflammatory disease.