Splicing inhibition mediated by reduced splicing factors and helicases is associated with the cellular response of lung cancer cells to cisplatin.

Lung cancer's mortality is predominantly linked to post-chemotherapy recurrence, driven by the reactivation of dormant cancer cells. Despite the critical role of these reactivated cells in cancer recurrence and metastasis, the molecular mechanisms governing their therapeutic selection remain poorly understood. In this study, we conducted an integrative analysis by combining PacBio single molecule real-time (SMRT) sequencing with short reads Illumina RNA-seq. Our study revealed that cisplatin-induced dormant and reactivated cancer cells exhibited a noteworthy reduction in gene transcripts and alternative splicing events. Particularly, the differential alternative splicing events were found to be overlapping with the differentially expression genes and enriched in genes related to cell cycle and cell division. Utilizing ENCORI database and correlation analysis, we identified key splicing factors, including SRSF7, SRSF3, PRPF8, and HNRNPC, as well as RNA helicase such as EIF4A3, DDX39A, DDX11, and BRIP1, which were associated with the observed reduction in alternative splicing and subsequent decrease in gene expression. Our study demonstrated that lung cancer cells reduce gene transcripts through diminished alternative splicing events mediated by specific splicing factors and RNA helicase in response to the chemotherapeutic stress. These findings provide insights into the molecular mechanisms underlying the therapeutic selection and reactivation of dormant cancer cells. This discovery opens a potential avenue for the development of therapeutic strategies aimed at preventing cancer recurrence following chemotherapy.

EphB1 promotes the differentiation and maturation of dendritic cells in non-small cell lung cancer.

EphB1 is implicated in numerous physiological and pathological processes, including nervous system diseases, cardiovascular diseases and cancers. It binds to membrane-bound ligands and drives bidirectional signaling. EphB1, along with its ligand ehrinB, plays a pivotal role in activating immune cells. However, despite its presence in dendritic cells (DCs), EphB1's involvement in the differentiation and maturation of DCs in cancers remains inadequately understood. In this study, we found compromised differentiation and maturation of DCs in EphB1-/- mice bearing lung adenocarcinoma syngeneic tumors. Our in vitro assays revealed that EphB1 phosphorylation induced DC differentiation and maturation. Cox-2, a key enzyme involved in the production of proinflammatory molecules, is implicated in DC differentiation induced by phosphorylated EphB1. Additionally, the study has identified lead compounds that specifically target EphB1 phosphorylation sites. Collectively, this research on EphB1 phosphorylation has provided valuable insights into the regulation of immune cell functionality and holds the potential for the development of innovative therapeutic strategies for a range of diseases.

Exosomes from cisplatin-induced dormant cancer cells facilitate the formation of premetastatic niche in bone marrow through activating glycolysis of BMSCs.

Introduction: Lung cancer is the leading cause of cancer-related deaths worldwide. Chemotherapy kills most cancer cells; however, residual cells enter a dormant state. The dormant cancer cells can be reactivated under specific circumstances. The "premetastatic niche" that is suitable for colonization of cancer cells is formed before the arrival of cancer cells. Tumor-derived exosomes are the main mediators of tumorigenesis. We are aiming to elucidate the roles of exosomes from cisplatin-induced dormant lung cancer cells in the formation of premetastatic niches in bone marrow. Methods: We performed differential proteomics in dormant A549 cell- and A549 cell-derived exosomes. Non-targeted metabolomics and RNA sequencing were performed to explore the molecular and metabolic reprogramming of bone marrow stromal cells (BMSCs). The growth and metastasis of A549 cells in vivo were monitored by bioluminescence imaging. Results: We found that Insulin-like growth factor 2 (IGF-2) and Insulin-like growth factor binding protein 2 (IGFBP2) were upregulated in dormant A549 cell-derived exosomes. BMSCs that took up exosomes from dormant A549 cells showed enhanced glycolysis and promoted the growth and metastasis of A549 cells possibly through Insulin-like growth factor 1 receptor (IGF-1R)-induced metabolic reprogramming. Inhibition of the production of lactate and IGF-1R signaling can suppress the growth and metastasis of A549 cells from bone marrow. Discussion: Overall, we demonstrated that BMSCs formed a premetastatic niche upon taking up exosomes from cisplatin-induced dormant lung cancer cells. BMSCs promoted lung cancer cell growth and metastasis through the reverse Warburg effect.

Cell-cell contact-driven EphB1 cis- and trans- signalings regulate cancer stem cells enrichment after chemotherapy.

Reactivation of chemotherapy-induced dormant cancer cells is the main cause of relapse and metastasis. The molecular mechanisms underlying remain to be elucidated. In this study, we introduced a cellular model that mimics the process of cisplatin responsiveness in NSCLC patients. We found that during the process of dormancy and reactivation induced by cisplatin, NSCLC cells underwent sequential EMT-MET with enrichment of cancer stem cells. The ATAC-seq combined with motif analysis revealed that OCT4-SOX2-TCF-NANOG motifs were associated with the enrichment of cancer stem cells induced by chemotherapy. Gene expression profiling suggested a dynamic regulatory mechanism during the process of enrichment of cancer stem cells, where Nanog showed upregulation in the dormant state and SOX2 showed upregulation in the reactivated state. Further, we showed that EphB1 and p-EphB1 showed dynamic expression in the process of cancer cell dormancy and reactivation, where the expression profiles of EphB1 and p-EphB1 showed negatively correlated. In the dormant EMT cells which showed disrupted cell-cell contacts, ligand-independent EphB1 promoted entry of lung cancer cells into dormancy through activating p-p38 and downregulating E-cadherin. On the contrary, in the state of MET, in which cell-cell adhesion was recovered, interactions of EphB1 and ligand EphrinB2 in trans promoted the stemness of cancer cells through upregulating Nanog and Sox2. In conclusion, lung cancer stem cells were enriched during the process of cellular response to chemotherapy. EphB1 cis- and trans- signalings function in the dormant and reactivated state of lung cancer cells respectively. It may provide a therapeutic strategy that target the evolution process of cancer cells induced by chemotherapy.

Chromatin accessibility regulates chemotherapy-induced dormancy and reactivation.

Cisplatin-based chemotherapy remains the standard care for non-small cell lung cancer (NSCLC) patients. Relapse after chemotherapy-induced dormancy affects the overall survival of patients. The evolution of cancer cells under chemotherapy stress is regulated by transcription factors (TFs) with binding sites initially buried deep within inaccessible chromatin. The transcription machinery and dynamic epigenetic alterations during the process of dormancy-reactivation of lung cancer cells after chemotherapy need to be investigated. Here, we investigated the chromatin accessibility of lung cancer cells after cisplatin treatment, using an assay for transposase-accessible chromatin sequencing (ATAC-seq). We observed that global chromatin accessibility was extensively improved. Transcriptional Regulatory Relationships Unraveled by Sentence-based Text mining (TRRUST) v.2 was used to elucidate TF-target interaction during the process of dormancy and reactivation. Enhancer regions and motifs specific to key TFs including JUN, MYC, SMAD3, E2F1, SP1, CTCF, SMAD4, STAT3, NFKB1, and KLF4 were enriched in differential loci ATAC-seq peaks of dormant and reactivated cancer cells induced by chemotherapy. The findings suggest that these key TFs regulated gene expressions during the process of dormancy and reactivation of cancer cells through altering promoter accessibility of target genes. Our study helps advance understanding of how cancer cells adapt to the stress induced by chemotherapy through TF binding motif accessibility.

Reassessment of the role of CaCO3 in n-butanol production from pretreated lignocellulosic biomass by Clostridium acetobutylicum.

In this study, the role of CaCO3 in n-butanol production was further investigated using corn straw hydrolysate (CSH) media by Clostridium acetobutylicum CICC 8016. CaCO3 addition stimulated sugars utilization and butanol production. Further study showed that calcium salts addition to CSH media led to the increase in Ca2+ concentration both intracellularly and extracellularly. Interestingly, without calcium salts addition, intracellular Ca2+ concentration in the synthetic P2 medium was much higher than that in the CSH medium despite the lower extracellular Ca2+ concentrations in the P2 medium. These results indicated that without additional calcium salts, Ca2+ uptake by C. acetobutylicum CICC 8016 in the CSH medium may be inhibited by non-sugar biomass degradation compounds, such as furans, phenolics and organic acids. Comparative proteomics analysis results showed that most enzymes involved in glycolysis, redox balance and amino acids metabolism were up-regulated with CaCO3 addition. This study provides further insights into the role of CaCO3 in n-butanol production using real biomass hydrolysate.