Tumor immunotherapy resistance: Revealing the mechanism of PD-1 / PD-L1-mediated tumor immune escape.

Tumor immunotherapy, an innovative anti-cancer therapy, has showcased encouraging outcomes across diverse tumor types. Among these, the PD-1/PD-L1 signaling pathway is a well-known immunological checkpoint, which is significant in the regulation of immune evasion by tumors. Nevertheless, a considerable number of patients develop resistance to anti-PD-1/PD-L1 immunotherapy, rendering it ineffective in the long run. This research focuses on exploring the factors of PD-1/PD-L1-mediated resistance in tumor immunotherapy. Initially, the PD-1/PD-L1 pathway is characterized by its role in facilitating tumor immune evasion, emphasizing its role in autoimmune homeostasis. Next, the primary mechanisms of resistance to PD-1/PD-L1-based immunotherapy are analyzed, including tumor antigen deletion, T cell dysfunction, increased immunosuppressive cells, and alterations in the expression of PD-L1 within tumor cells. The possible ramifications of altered metabolism, microbiota, and DNA methylation on resistance is also described. Finally, possible resolution strategies for dealing with anti-PD-1/PD-L1 immunotherapy resistance are discussed, placing particular emphasis on personalized therapeutic approaches and the exploration of more potent immunotherapy regimens.

Real-world tobacco cessation practice in China: findings from the prospective, nationwide multicenter China National Tobacco Cessation Cohort Study (CNTCCS).

Background: Tobacco cessation is proven to be the most effective and cost-effective strategy for smokers to reduce their risk of smoking-related disease and premature death. Providing effective, efficient, safe, and patient-centred tobacco cessation treatment to reach those who need them is a significant challenge. To date, only a few nationwide studies in China have assessed the overall clinical care practice and treatment outcome of tobacco cessation. Methods: This a prospective, nationwide, multicenter, cohort study covering all Eastern China, Northwest China, Central China, North China, Southwest China, Northeast China, and South China. Participants who were current smokers aged 18-85 years attending clinic for smoking cessation were included. All the participants were treated with 3-month cessation treatment and followed up for 3 months. Data were collected prospectively using online system. The primary outcome was 7-day point abstinence rate at 24 weeks, validated biochemically by an expired carbon monoxide level of less than 10 ppm. The participants lost to follow-up or not providing validation were included as non-abstainers. Findings: A representative sample of 3557 participants were recruited and 2943 participants were included into this analysis. These participants had mean age of 53.05 years, and 94.8% were males, with 75.8% showing symptoms of tobacco dependence. A total of 965 (32.8%) participants were treated with Bupropion + behavioural counselling, followed by 935 (31.8%) with behavioural counselling, 778 (26.4%) with Varenicline + behavioural counselling, 135 (4.6%) with alternative treatments + behavioural counselling, and 130 (4.4%) with nicotine replacement therapy (NRT) + behavioural counselling. After 3-month treatment and 3-month follow-up, 21.74% of the participants quit smoking at 24 weeks. In the multivariable-adjusted analyses, quitting smoking was significantly associated with female, higher socioeconomic status, poor health condition, different treatment received, and less smoking intensity. The tobacco cessation treatment varied widely across different areas of China. In particular, the areas with higher usage of cessation medication were associated with better cessation treatment outcome. Interpretation: The CNTCCS is the first large-scale nationwide cohort study of smoking cessation in China. Rich data collected from this prospective cohort study provided the opportunity to evaluate the clinical practice of tobacco cessation treatment in China. Funding: Chinese Academy of Medical Sciences (CAMS) Initiative for Innovative Medicine (CAMS 2021-I2M-1-010), Heilongjiang Provincial Science and Technology Key Program (2022ZXJ03C02), and National Key R&D Program of China (grant no. 2017YFC1309400).

SIRT7 affects autophagy and activation of hepatic stellate cells by regulating the acetylation level of high mobility group protein 1.

OBJECTIVE: Preventing the progression of hepatic fibrosis is an important strategy to improve the prognosis of liver disease. The purpose of this study was to investigate the role of sirtuin7 (SIRT7) and high mobility group box 1 (HMGB1) acetylation in the occurrence and development of hepatic fibrosis. MATERIALS AND METHODS: Hepatic fibrosis mice model was induced by CCl4. TGF-ß1 was used to activated quiescent hepatic stellate cell (qHSC) into activated HSC (aHSC). Hematoxylin-eosin evaluated hepatic fibrosis in vivo, and the distribution of α-smooth muscle actin (α-SMA) or HMGB1 was detected by immunohistochemistry or immunofluorescence. The expressions of SIRT7, autophagy related proteins, and HSC activation-related proteins were detected by Western blot. Immunoprecipitation detected the acetylation level of HMGB1. Lysine mutants of HMGB1 were constructed in vitro to explore the acetylation sites of HMGB1. RESULTS: Hepatocyte autophagy and activation levels were enhanced in CCl4 group or aHSC group, and the acetylation level of HMGB1 was increased. Nuclear transfer of HMGB1 occurred in aHSC, and HMGB1was mainly distributed in cytoplasm. The expression of SIRT7 in CCl4 group or aHSC group was most significantly decreased, and knockdown of SIRT7 leads to increased levels of HSCs autophagy and activation. Overexpression of SIRT7 or interference of HMGB1 alone in aHSC can reduce the level of autophagy and activation of aHSC. However, continued overexpression of SIRT7 in shHMGB1-aHSC could not reduce the autophagy and activation levels of aHSC. Among the 11 Flag-HMGB1 mutants, the acetylation level of K86R-Flag-HMGB1 was the lowest. The acetylation level of K86R-Flag-HMGB1 did not change due to SIRT7 downregulation. CONCLUSION: This study proved that SIRT7 can directly target the K86R site of HMGB1 and participate in regulating the expression and distribution of HMGB1, thus affecting the autophagy and activation level of HSCs.

Phosphorus facilitation and covariation of root traits in steppe species.

Different phosphorus (P)-acquisition strategies may be relevant for species coexistence and plant performance in terrestrial communities on P-deficient soils. However, how interspecific P facilitation functions in natural systems is largely unknown. We investigated the root physiological activities for P mobilization across 19 coexisting plant species in steppe vegetation, and then grew plants with various abilities to mobilize sorbed P in a microcosm in a glasshouse. We show that P facilitation mediated by rhizosphere processes of P-mobilizing species promoted growth and increased P content of neighbors in a species-specific manner. When roots interacted with a facilitating neighbor, Cleistogenes squarrosa and Bromus inermis tended to show greater plasticity of root proliferation or rhizosheath acid phosphatase activity compared with other non-P-mobilizing species. Greater variation in these root traits was strongly correlated with increased performance in the presence of a facilitator. The results also show, for the first time, that P facilitation was an important mechanism underlying a positive complementarity effect. Our study highlights that interspecific P-acquisition facilitation requires that facilitated neighbors exhibit a better match of root traits with a facilitating species. It provides a better understanding of species coexistence in P-limited communities.

Overexpressing microRNA-34a overcomes ABCG2-mediated drug resistance to 5-FU in side population cells from colon cancer via suppressing DLL1.

Colon cancer side population (SP) cells are a small subset of cancer cells that have cancer stemness capacity and enhanced drug resistance. ABCG2 is a multidrug resistance-related protein in SP cells and has been demonstrated to be regulated by Notch signalling pathway. Recently, microRNAs are reported to play a critical role in SP cell fate. However, their role in ABCG2-mediated drug resistance in colon cancer SP cells remains unclear. In the current study, the different expressions of miR-552, miR-611, miR-34a and miR-5000-3p were compared within SP and non-SP cells, which were separated from human colon cancer cell lines (SW480 and LoVo). We found that miR-34a was significantly down-regulated in SP cells and that overexpressing miR-34a overcame drug resistance to 5-fluorouracil (5-FU). The luciferase reporter assay indicated that miR-34a negatively regulated DLL1, a ligand of Notch signalling pathway, via binding with 3'-untranslated region of its messenger RNA. In addition, overexpressing miR-34a overcame ABCG2-mediated resistance to 5-FU via DLL1/Notch pathway in vitro, and suppressed tumour growth under 5-FU treatment in vivo. In conclusion, our findings suggest that miR-34a acts as a tumour suppressor via enhancing chemosensitivity to 5-FU in SP cells, which provides a novel therapeutic target in chemotherapy-resistant colon cancer.

Long noncoding RNA XIST enhances ethanol-induced hepatic stellate cells autophagy and activation via miR-29b/HMGB1 axis.

Activation of hepatic stellate cells (HSCs) is a prominent driver of liver fibrogenesis, including alcoholic liver fibrosis (ALF). Furthermore, autophagy contributes to HSCs activation. This study aims to investigate the role and the mechanisms of long noncoding RNA XIST in regulating HSCs autophagy and activation. Human HSC cells (LX-2) were treated with 100 mmol/L ethanol to mimic HSCs activation. The HSCs activation was evaluated by determining cell viability and protein levels of fibrosis markers α-smooth muscle actin (α-SMA) and collagen type 1 α1 (CoL1A1). The autophagy was evaluated by measuring autophagy markers Beclin-1 and LC3-II. The interaction among XIST, miR-29b, and high-mobility group box-1 (HMGB1) were analyzed using luciferase reporter assay, qRT-PCR, and western blot. Lentiviruses targeting sh-XIST (LV-sh-XIST) were injected into ALF model mice via tail vein to elucidate the in vivo role of XIST in ALF injury. XIST was upregulated in ethanol-activated LX-2 cells. Furthermore, XIST served as a competitive endogenous RNA of miR-29b to facilitate HMGB1 expression, and thus enhanced ethanol-induced HSCs autophagy and activation. Further in vivo assay showed that downregulation of XIST by LV-sh-XIST alleviated ALF injury in ALF model mice. Collectively, XIST enhances ethanol-induced HSCs autophagy and activation via miR-29b/HMGB1 axis.

Aspirin enhances the sensitivity of hepatocellular carcinoma side population cells to doxorubicin via miR-491/ABCG2.

Objective: To explore whether aspirin (ASA) enhances the sensitivity of hepatocellular carcinoma (HCC) side population (SP) cells to doxorubicin (Doxo) via miR-491/ATP-binding cassette sub-family G member 2 (ABCG2).Methods: Non-SP and SP cells were isolated from MHCC-97L cell line using flow cytometry analysis and fluorescence-activated cell sorting. Colony formation assay was performed to determine the colony-formation ability of cells. Cell viability of SP cells was determined with the MTT assay. Luciferase reporter assay was applied in confirming the binding between miR-491 and ABCG2.Results: Although the Doxo treatment lowered the colony-formation ability of both non-SP and SP cells, the colony-formation ability of SP cells was 2-fold higher than that of non-SP cells (P<0.05). Doxo slightly inhibited the cell viability of SP cells in a concentration-dependent manner; the addition of ASA dramatically enhanced the inhibitory effect of Doxo on SP cell viability in a concentration-dependent manner (P<0.05). Compared with non-SP cells, the miR-491 expression was significantly decreased in SP cells, which was significantly reversed by ASA (P<0.05). miR-491 directly controlled the ABCG2 expression. In the presence of Doxo, miR-491 inhibitor reduced the inhibitory effect of ASA on the cell viability of SP cells, which was significantly reversed by knockdown of ABCG2 (P<0.05).Conclusion: ASA enhanced the sensitivity of SP cells to Doxo via regulating the miR-491/ABCG2 signaling pathway.

Inhibition of autophagy reverses alcohol-induced hepatic stellate cells activation through activation of Nrf2-Keap1-ARE signaling pathway.

BACKGROUND: Numerous documents have indicated a critical role of autophagy in alcoholic liver fibrosis (ALF), but few papers have reported its function in hepatic stellate cells (HSCs) activation. The current study aimed to investigate the regulation effect of autophagy in HSCs activation, in further to explore the underlying mechanism involved. METHODS: HSC-T6 cells were treated with ethanol, 3-MA (autophagy inhibitor) or rapamycin (autophagy inducer), and cells were also transfected with si-Nrf2 or si-Keap1. Moreover, ALF animal model was established and Nrf-2(-/-), Keap1 (-/-) mice were purchased. The level of autophagy, the expression of α-SMA and CoL1A1, and Nrf2 antioxidant response were evaluated in stellate cells and livers. RESULTS: Ethanol treatment in cultured cells increased autophagy, oxidative stress level and promoted HSCs activation. Inhibition of autophagy reversed alcohol-induced HSCs activation and suppressed HSCs oxidative stress. Nrf2-Keap1-ARE pathway was involved in HSCs activation and oxidative stress regulated by autophagy. In addition, through in vivo study, we found that inhibition of autophagy could alleviate alcoholic fatty liver injury in ALF model mice and Nrf2 signaling was involved in autophagy regulated HSCs activation. CONCLUSION: These data implicated mechanisms underlying autophagy in regulating the fibrogenic response in HSCs activation.

[Effects of Cu2+ stress on DNA polymorphism of genome in foxtail millet of different genotypes].

Cu2+ is an essential element for plant growth, and is one of the major elements in the environment. In order to investigate the physiological characteristics and geno-toxicity effects of foxtail millet (Setaria italica (L) Beauv) under different Cu2+ stress, four genotypes of foxtail millet (Zhaogu, Huangmi, An06, D2-8) from Shanxi, China were cultivated for 30 days in a pot filled with soil of with different mass concentrations of Cu2+ (0, 50, 100, 200, 400 mg.kg-l). Effects of Cu2+ stress on DNA damage of genome in foxtail millet were studied using random amplified polymorphic DNA (RAPD) , and the contents of soluble sugar, proline and MDA were tested. The result showed that the content of soluble sugar had a trend of initial increased followed by decline in all four foxtail millet seedlings in response to the rising Cu2+ concentration, and the maximum value was 50 mg.kg-1. At Cu2 concentrations of 200 mg. kg-1 or more, the soluble sugar content in the four kinds of millet showed an average reduction of 32.44% to 56.5% compared to that of the control group. The result showed that proline synthesis was enhanced at low concentrations (less than 50 mg.kg-1) , but inhibited at high concentrations (more than 100 mg.kg-1), and the contents of MDA in the four genotypes of foxtail millet were significantly increased compared with the control group (P <0. 05). The changes occurring in random amplified polymorphic DNA profiles of the four genotypes of foxtail millet following Cu' treatment included loss of normal bands, appearance of new bands and variation in band intensity compared to the plantlet without treatment, showing that Cu2+ significantly affected the stability of the genomic DNA in the cells of millet seedlings. Additionally, the effect of DNA polymorphism changes was dose-dependent with the Cu2+ concentration. The different genotypes of millet showed different response in the physiological and genetic damage under Cu2+ stress. The change of DNA polymorphism using RAPD technique could be used as the biomarkers to find genotoxic effects of Cu2+.

Overexpression of SUMO-1 in hepatocellular carcinoma: a latent target for diagnosis and therapy of hepatoma.

PURPOSE: To investigate the expression of SUMO-1 in human hepatocellular carcinoma (HCC) cell lines and clinical HCC samples. METHODS: RT-PCR and Western blot were used to detect the expressions of SUMO-1 in HCC cell lines, clinical HCC samples,and the non-neoplastic liver tissues adjacent to HCC. After transfection of SUMO-1 siRNA into HCC cell line SMMC-7721, the expression levels of Bcl-2, c-Myc and α-tubulin were examined, and MTT assay and cell cycle analysis were carried out as well. RESULTS: Overexpressions of SUMO-1 were detected in HCC cell lines and clinical HCC samples, while the expression level of SUMO-1 in the non-neoplastic liver tissues was significantly lower (P < 0.001). Transfection of SUMO-1 siRNA resulted in 73.43% of maximal silencing efficiency of SUMO-1 in 48 h. The expressions of Bcl-2 and c-Myc were down-regulated coincidentally. SUMO-1 siRNA notably inhibited SMMC-7721 cells proliferation in vitro and increased the ratios of G2 phase and S phase in the cells. CONCLUSIONS: Owing to overexpression of SUMO-1 in HCC and its important role in the development of HCC, SUMO-1 could be a latent target in diagnosis and therapy of HCC.

[DNA content and its correlation with biological behavior of non-small cell lung cancer].

OBJECTIVE: To analyze the relationship between DNA content and biological behavior and its prognostic significance in non-small cell lung cancer. METHODS: Tumor DNA content was determined by flow cytometry in the specimens from 58 patients with resected non-small cell lung cancer. The DNA content of each cell subpopulation was expressed as the DNA index (DI), and an internal standard was provided by the normal pulmonary parenchymal cells in the same specimen. The prognostic value of DNA content in non-small cell lung cancer was assessed by Cox's model analysis. RESULTS: In qualitative analysis, there was no relationship between DNA ploidy (diploidy or aneuploidy) and the following factors: tumor size, metastasis of lymph node, clinical stage, pathologic type, pathologic grade or survival. In quantitative analysis, high DNA index was observed in tumor size > 3 cm, metastasis of lymph node, stage III/IV, adenocarcinoma and shorter survival, which was statistically significant. Cox's model analysis showed that DNA index was a prognostic factor in non-small cell lung cancer and DNA index > 2.0 was an independent prognostic factor. CONCLUSION: DNA index analysis is useful for the evaluation of the biological behavior and the prognosis of non-small cell lung cancer.