Comprehensive pan-cancer analysis of role of GPRASP1, associated with clinical outcomes, immune microenvironment, and immunotherapeutic efficiency in pancreatic cancer.

BACKGROUND: GPRASP1 (G-protein-coupled receptor-associated sorting protein 1) plays an important role in tumorigenesis. However, GPRASP1 specific role has not been clearly clarified in cancer, particularly in pancreatic cancer(PC). METHODS: Firstly, we utilized pan-cancer analysis based on RNA sequencing data from TCGA (The Cancer Genome Atlas) to evaluate the expression pattern and immunological role of GPRASP1. Then, through multiple transcriptome datasets (TCGA and Gene Expression Omnibus (GEO)) and multi-omics (RNA-seq, DNA methylation, copy number variations (CNV), somatic mutation data) in-depth analysis, we comprehensively explore the relationship of GPRASP1 expression with clinicopathologic characteristics, clinical outcomes, CNV, and DNA methylation in pancreatic cancer. Additionally, we employed immunohistochemistry (IHC) to further confirm GPRASP1 expression pattern between PC tissues and paracancerous tissues. Lastly, we systematically associated the GPRASP1 with immunological properties from numerous perspectives, such as immune cell infiltration, immune-related pathways, immune checkpoint inhibitors, immunomodulators, immunogenicity, and immunotherapy. RESULTS: Through pan-cancer analysis, we identified that GPRASP1 plays a critical role in the occurrence and prognosis of PC, and is closely related to immunological characteristics in PC. IHC analysis confirmed that GPRASP1 is significantly down-regulated in PC compared with normal tissues. The expression of GPRASP1 is significantly negatively correlated with clinical features (histologic grade, T stage, and TNM stage), and is an independent predictor of favorable prognosis, regardless of other clinicopathological features (HR: 0.69, 95% CI 0.54-0.92, p= 0.011). The etiological investigation found that the abnormal expression of GPRASP1 was related to DNA methylation and CNV frequency. Subsequently, the high expression of GPRASP1 was significantly correlated with immune cell infiltration (CD8 + T cell, tumor-infiltrating lymphocyte(TIL)), immune-related pathways(cytolytic activity, check-point, human leukocyte antigen (HLA)), immune checkpoint inhibitors (CTLA4, HAVCR2, LAG3, PDCD1 and TIGIT), immunomodulators ( CCR4/5/6, CXCL9, CXCR4/5), and immunogenicity(immune score, neoantigen, TMB(tumor mutation burden)). Finally, IPS (immunophenoscore) and TIDE (tumor immune dysfunction and exclusion) analysis demonstrated that GPRASP1 expression levels can accurately predict the immunotherapeutic response. CONCLUSION: GPRASP1 is a promising candidate biomarker that plays a role in the occurrence, development, and prognosis of PC. Evaluating GPRASP1 expression will aid in the characterization of tumor microenvironment (TME) infiltration and orient more efficient immunotherapy strategies.

Undifferentiated destruction of mitochondria by photoacoustic shockwave to overcome chemoresistance and radiation resistance in cancer therapy.

Resistance to either radiation or chemotherapy remains a complex and stubborn obstacle in cancer therapy and is responsible for a significant portion of the treatment failure. While the underlying mechanisms of the resistance are often associated with multiple factors, direct destruction of mitochondria is likely to ensure the ultimate death of the cell. Herein, a strategy of precise mitochondrial destruction using a photoacoustic (PA) shockwave was proposed to overcome chemoresistance and radiation resistance in cancer therapy. A nanoparticle featuring mitochondria-targeting and high near-infrared absorbance is constructed. The nanoparticle was found to indiscriminately localize in the mitochondria of both parental and its corresponding resistant tumor cells due to the mitochondrial transmembrane potential. By absorbing a controllable amount of energy from a pulsed laser, the nanoparticle could generate a mechanical PA shockwave that physically damages the mitochondria leading to the opening of apoptotic pathways and thus yielding a precision antitumor effect. The cell-killing efficiency was validated in vitro and in vivo. The results demonstrate that a PA shockwave can result in undifferentiated killing of the resistant tumor cells via destruction of mitochondria. Given the critical importance of resistant tumor cells, although at its preliminary stage, the proposed modality may open a new window in cancer therapy.

Regulatory coupling between long noncoding RNAs and senescence in irradiated microglia.

BACKGROUND: Microglia have been implicated in the pathogenesis of radiation-induced brain injury (RIBI), which severely influences the quality of life during long-term survival. Recently, irradiated microglia were speculated to present an aging-like phenotype. Long noncoding RNAs (lncRNAs) have been recognized to regulate a wide spectrum of biological processes, including senescence; however, their potential role in irradiated microglia remains largely uncharacterized. METHODS: We used bioinformatics and experimental methods to identify and analyze the senescence phenotype of irradiated microglia. Western blotting, enzyme-linked immunosorbent assays, immunofluorescence, and quantitative real-time reverse transcription-polymerase chain reaction were performed to clarify the relationship between the radiation-induced differentially expressed lncRNAs (RILs) and the distinctive molecular features of senescence in irradiated microglia. RESULTS: We found that the senescence of microglia could be induced using ionizing radiation (IR). A mutual regulation mode existed between RILs and three main features of the senescence phenotype in irradiated microglia: inflammation, the DNA damage response (DDR), and metabolism. Specifically, for inflammation, the expression of two selected RILs (ENSMUST00000190863 and ENSMUST00000130679) was dependent on the major inflammatory signaling pathways of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK). The two RILs modulated the activation of NF-κB/MAPK signaling and subsequent inflammatory cytokine secretion. For the DDR, differential severity of DNA damage altered the expression profiles of RILs. The selected RIL, ENSMUST00000130679, promoted the DDR. For metabolism, blockade of sterol regulatory element-binding protein-mediated lipogenesis attenuated the fold-change of several RILs induced by IR. CONCLUSIONS: Our findings revealed that certain RILs interacted with senescence in irradiated microglia. RILs actively participated in the regulation of senescence features, suggesting that RILs could be promising intervention targets to treat RIBI.

Regulating glioma stem cells by hypoxia through the Notch1 and Oct3/4 signaling pathway.

To investigate the effects of hypoxia on the features of cancer stem cells in the glioma cancer U87 cell line and underlying mechanism, stem cell markers and features in U87 were studied under the hypoxic and normoxic culture conditions by reverse transcription-quantitative polymerase chain reaction, western blot analysis, MTT, a colony formation test and flow cytometry. Compared to the normoxic group, the cluster of differentiation 133+ phenotype, clone formation rate and cell vitality were significantly elevated in U87 cells cultured in a hypoxic microenvironment. Also, the mRNA and protein expression of neurogenic locus notch homolog protein 1 (Notch1) and Oct3/4 were significantly elevated in U87 cells cultured in a hypoxic microenvironment, however, transcription factor SOX-2 expression was not significantly changed. These results indicate that hypoxia can promote the proliferation of glioma stem cells and maintain the characteristics of stem cells through the activation of Notch1 and Oct3/4 or Notch1 activation, affecting the biological characteristics of glioma cells.

[Enhancement of NMDA receptor sensitivity by thrombin and its relationship with tissue transglutaminase].

OBJECTIVE: To explore the possible relationship between the thrombin induced potentiation of rat cerebellum granular cell N-methyl-D-aspartate (NMDA) receptor function and the change of intracellular tissue transglutaminase (tTG). METHODS: Primary cultured rat cerebellum granular cells were pretreated by using thrombin (0.01 U/ml) with or without co-pretreatment of 0.5 x 10(-4) mol/L MDC (monodansylcadaverine, a tTG inhibitor) 30 minutes. Induce cells mentioned above to undergo apoptosis with different concentration of NMDA (0.1 x 10(-4) mol/L, 0.25 x 10(-4) mol/L and 0.5 x 10(-4) mol/L). Flowcytometer was applied 3 hours later to detect the changed function of NMDA receptor by counting percentage of apoptotic cells. RT-PCR was used to compare the tTG mRNA level in the cerebellum granular cells treated with NMDA of same dosage with/without thrombin pretreatment. RESULTS: Thrombin pretreatment increased the percentage of apoptosis cells induced by NMDA [(8.3 +/- 0.5)% to (15.1 +/- 0.8)% at 0.1 x 10(-4) mol/L, (14.1 +/- 1.1)% to (23.8 +/- 0.7)% at 0.25 x 10(-4) mol/L, (26.8 +/- 1.9)% to (33.7 +/- 2.1)% at 0.5 x 10(-4) mol/L)]; and this effect was inhibited by co-pretreatment MDC with thrombin, cell apoptosis decreased to (5.8 +/- 1.2)%, (11.5 +/- 1.5)% and (19.0 +/- 1.7)%; Thrombin increased intracellular tTG mRNA levels comparing with those without thrombin pretreatment. CONCLUSION: Thrombin potentiates rat cerebellum granular cell NMDA receptor function by increasing intracellular tissue transglutaminase.