salubrinal and Lung-Neoplasms

Marsdenia Tenacissima (Roxb.) Wight et Arn. is a traditional Chinese medicine. Its standardized extract (MTE), with the trade name Xiao-Ai-Ping injection, is widely used for cancer treatment. The pharmacological effects of MTE-inducing cancer cell death have been primarily explored. However, whether MTE triggers tumor endoplasmic reticulum stress (ERS)-associated immunogenic cell death (ICD) is unknown.. To determine the potential role of endoplasmic reticulum stress in the anti-cancer effects of MTE, and uncover the possible mechanisms of endoplasmic reticulum stress-associated immunogenic cell death induced by MTE.. The anti-tumor effects of MTE on non-small cell lung cancer (NSCLC) were examined through CCK-8 and wound healing assay. Network pharmacology analysis and RNA-sequencing (RNA seq) were performed to confirm the biological changes of NSCLCs after MTE treatment. Western blot, qRT-PCR, reactive oxygen species (ROS) assay, and mitochondrial membrane potential (MMP) assay were used to explore the occurrence of endoplasmic reticulum stress. Immunogenic cell death-related markers were tested by ELISA and ATP release assay. Salubrinal was used to inhibit the endoplasmic reticulum stress response. SiRNA and bemcentinib (R428) were used to impede the function of AXL. AXL phosphorylation was regained by recombinant human Gas6 protein (rhGas6). The effects of MTE on endoplasmic reticulum stress and immunogenic cell death response were also proved in vivo. The AXL inhibiting compound in MTE was explored by molecular docking and confirmed by Western blot.. MTE inhibited cell viability and migration of PC-9 and H1975 cells. Enrichment analysis identified that differential genes after MTE treatment were significantly enriched in endoplasmic reticulum stress-related biological processes. MTE decreased mitochondrial membrane potential (MMP) and increased ROS production. Meanwhile, endoplasmic reticulum stress-related proteins (ATF6, GRP-78, ATF4, XBP1s, and CHOP) and immunogenic cell death-related markers (ATP, HMGB1) were upregulated, and the AXL phosphorylation level was suppressed after MTE treatment. However, when salubrinal (an endoplasmic reticulum stress inhibitor) and MTE were co-treated cells, the inhibitory effects of MTE on PC-9 and H1975 cells were impaired. Importantly, inhibition of AXL expression or activity also promotes the expression of endoplasmic reticulum stress and immunogenic cell death-related markers. Mechanistically, MTE induced endoplasmic reticulum stress and immunogenic cell death by suppressing AXL activity, and these effects were attenuated when AXL activity recovered. Moreover, MTE significantly increased the expression of endoplasmic reticulum stress-related markers in LLC tumor-bearing mouse tumor tissues and plasma levels of ATP and HMGB1. Molecular docking illustrated that kaempferol has the strongest binding energy with AXL and suppresses AXL phosphorylation.. MTE induces endoplasmic reticulum stress-associated immunogenic cell death in NSCLC cells. The anti-tumor effects of MTE are dependent upon endoplasmic reticulum stress. MTE triggers endoplasmic reticulum stress-associated immunogenic cell death by inhibiting AXL activity. Kaempferol is an active component that inhibits AXL activity in MTE. The present research revealed the role of AXL in regulating endoplasmic reticulum stress and enriched the anti-tumor mechanisms of MTE. Moreover, kaempferol may be considered a novel AXL inhibitor.

Topics: Adenosine Triphosphate; Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Endoplasmic Reticulum Stress; HMGB1 Protein; Humans; Immunogenic Cell Death; Kaempferols; Lung Neoplasms; Marsdenia; Mice; Molecular Docking Simulation; Plant Extracts; Reactive Oxygen Species

Cisplatin-based chemotherapy is considered a golden standard for treatment of advanced non-small cell lung cancer (NSCLC). However, drug resistance is one of the major problems in NSCLC chemotherapy. The mechanisms and related biological pathways that contribute to chemoresistance are relatively poorly understood. Here, we demonstrated that the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) suppresses cisplatin-induced A549 cell apoptosis. Cisplatin induced eIF2α phosphorylation through protein kinase RNA. Importantly, phospho-eIF2α inhibited cisplatin-induced A549 cells apoptosis, at least in part, by suppressing the p38 pathway. Moreover, analysis of tissue microarrays information demonstrated that phospho-eIF2α predicted a poor prognosis in patients with NSCLC. Taken together, these results provide a potential mechanism that is used for explaining how eIF2α promotes cisplatin resistance in A549 cells. Therefore, the regulation of eIF2α may improve treatment outcomes of cisplatin-based chemotherapy for patients with NSCLC.

Topics: Aged; Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cinnamates; Cisplatin; Drug Resistance, Neoplasm; eIF-2 Kinase; Enzyme Activation; Enzyme Inhibitors; Eukaryotic Initiation Factor-2; Female; Humans; Imidazoles; Lung Neoplasms; Male; Middle Aged; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Prognosis; Pyridines; Signal Transduction; Thiourea; Tissue Array Analysis