Multifactor assessment of ovarian cancer reveals immunologically interpretable molecular subtypes with distinct prognoses.

Background: Ovarian cancer (OC) is a highly heterogeneous and malignant gynecological cancer, thereby leading to poor clinical outcomes. The study aims to identify and characterize clinically relevant subtypes in OC and develop a diagnostic model that can precisely stratify OC patients, providing more diagnostic clues for OC patients to access focused therapeutic and preventative strategies. Methods: Gene expression datasets of OC were retrieved from TCGA and GEO databases. To evaluate immune cell infiltration, the ESTIMATE algorithm was applied. A univariate Cox analysis and the two-sided log-rank test were used to screen OC risk factors. We adopted the ConsensusClusterPlus algorithm to determine OC subtypes. Enrichment analysis based on KEGG and GO was performed to determine enriched pathways of signature genes for each subtype. The machine learning algorithm, support vector machine (SVM) was used to select the feature gene and develop a diagnostic model. A ROC curve was depicted to evaluate the model performance. Results: A total of 1,273 survival-related genes (SRGs) were firstly determined and used to clarify OC samples into different subtypes based on their different molecular pattern. SRGs were successfully stratified in OC patients into three robust subtypes, designated S-I (Immunoreactive and DNA Damage repair), S-II (Mixed), and S-III (Proliferative and Invasive). S-I had more favorable OS and DFS, whereas S-III had the worst prognosis and was enriched with OC patients at advanced stages. Meanwhile, comprehensive functional analysis highlighted differences in biological pathways: genes associated with immune function and DNA damage repair including CXCL9, CXCL10, CXCL11, APEX, APEX2, and RBX1 were enriched in S-I; S-II combined multiple gene signatures including genes associated with metabolism and transcription; and the gene signature of S-III was extensively involved in pathways reflecting malignancies, including many core kinases and transcription factors involved in cancer such as CDK6, ERBB2, JAK1, DAPK1, FOXO1, and RXRA. The SVM model showed superior diagnostic performance with AUC values of 0.922 and 0.901, respectively. Furthermore, a new dataset of the independent cohort could be automatically analyzed by this innovative pipeline and yield similar results. Conclusion: This study exploited an innovative approach to construct previously unexplored robust subtypes significantly related to different clinical and molecular features for OC and a diagnostic model using SVM to aid in clinical diagnosis and treatment. This investigation also illustrated the importance of targeting innate immune suppression together with DNA damage in OC, offering novel insights for further experimental exploration and clinical trial.

CysLT2 receptor mediates lipopolysaccharide-induced microglial inflammation and consequent neurotoxicity in vitro.

Neuroinflammation induced by microglial activation plays a critical role in many neurodegenerative diseases, including Parkinson's disease (PD). Recent studies have indicated that cysteinyl leukotriene receptor 2 (CysLT2R) is involved in inflammation and brain injury after cerebral ischemia. However, the role of CysLT2R in microglial responses associated with PD remains unclear. In the present study, we determined the regulatory roles of CysLT2R in microglial inflammation and subsequent neurotoxicity in an in vitro brain inflammation model induced by the microglial activator lipopolysaccharide (LPS). We found that LPS induced phagocytosis of a murine microglial cell line (BV-2 cells) and increased production of the proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß). The expression of CysLT2R protein was up-regulated and the nuclear translocation of CysLT2R was induced in LPS-activated BV-2 cells. CysLT2R selective antagonist HAMI 3379 significantly inhibited LPS-induced phagocytosis and overproduction of the cytokines in BV-2 cells. Similarly, the CysLT2R silencing by specific short hairpin RNA (shRNA) had the same effects as those of HAMI 3379, suggesting that the effect might be CysLT2R-dependent. Furthermore, the conditioned medium (CM) derived from LPS-treated BV-2 cells induced the cell death of a rat adrenal pheochromocytoma cell line (PC12). HAMI 3379 and CysLT2R shRNA attenuated neuronal death by suppressing the production of neurotoxic cytokines released from LPS-activated microglia. Collectively, these results suggest that CysLT2R mediates LPS-induced microglial inflammation and consequent neurotoxicity. CysLT2R may be a promising molecular target that modulates microglia-related neuroinflammation in neurodegenerative disorders, such as PD.

Regulation of rotenone-induced microglial activation by 5-lipoxygenase and cysteinyl leukotriene receptor 1.

The 5-lipoxygenase (5-LOX) products cysteinyl leukotrienes (CysLTs) are potent pro-inflammatory mediators. CysLTs mediate their biological actions through activating CysLT receptors (CysLT(1)R and CysLT(2)R). We have recently reported that 5-LOX and CysLT(1)R mediated PC12 cell injury induced by high concentrations of rotenone (0.3-10 µM), which was reduced by the selective 5-LOX inhibitor zileuton and CysLT(1)R antagonist montelukast. The purpose of this study was to examine the regulatory roles of the 5-LOX/CysLT(1)R pathway in microglial activation induced by low concentration rotenone. After mouse microglial BV2 cells were stimulated with rotenone (0.3-3 nM), phagocytosis and release of pro-inflammatory cytokine were assayed as indicators of microglial activation. We found that rotenone (1 and 3 nM) increased BV2 microglial phagocytosis and the release of the pro-inflammatory cytokines interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α). Zileuton and montelukast prevented rotenone (3 nM)-induced phagocytosis and cytokine release. Furthermore, rotenone significantly up-regulated 5-LOX expression, induced 5-LOX translocation to the nuclear envelope, and increased the production of CysLTs. These responses were inhibited by zileuton. Rotenone also increased CysLT(1)R expression and induced nuclear translocation of CysLT(1)R. In primary rat microglia, rotenone (10 nM) increased release of IL-1ß and TNF-α, whereas zileuton (0.1 µΜ) and montelukast (0.01 µΜ) significantly inhibited this response. These results indicated that 5-LOX and CysLT(1)R might be key regulators of microglial activation induced by low concentration of rotenone. Interference of 5-LOX/CysLT(1)R pathway may be an effective therapeutic strategy for microglial inflammation.

Stimulation of autophagy prevents amyloid-ß peptide-induced neuritic degeneration in PC12 cells.

Autophagy is a lysosomal degradative process essential for neuronal homeostasis, whereas autophagic failure has been linked to accumulating neurodegenerative disorders. However, the precise role of autophagy in axonal and dendritic degeneration in Alzheimer's disease (AD) remains unclear. In this study, we aim to investigate the precise effect of autophagy in amyloid-ß peptide (Aß)25-35-mediated neurite degeneration. Aß35-25, the non-neurotoxic reverse sequence analogue of Aß25-35, was used as a negative control. Our results showed that Aß25-35 dose-dependently suppressed PC12 proliferation and induced autophagy induction in neurites (axons and dendrites). A high proportion of autophagic structures in PC12 neurites were autolysosomes after 24 h of Aß25-35 treatment. Autophagy inhibition by 3-methyladenine (3MA), LY294002, and chloroquine (CQ) could not relieve the Aß25-35-induced neurite degeneration, while administration of autophagy stimulator rapamycin or AR-12 efficiently suppressed neurite degeneration. Autophagosomes colocalized with fragmented mitochondria after Aß25-35 treatment. Similar results were obtained using in vitro cultured superior cervical ganglion neurons. These findings demonstrate that autophagy stimulation may prevent neuritic degeneration following Aß25-35 treatment. Upregulation of autophagic activity may provide a valuable approach for the treatment of axonal and dendritic dystrophy in AD patients.