Drug-resistant exosome miR-99b-3p induces macrophage polarization and confers chemoresistance on sensitive cells by targeting PPP2CA.

The most frequent cancer in women to be diagnosed is breast cancer, and chemotherapy's ability to be effective is still significantly hampered by drug resistance. Tumor-derived exosomes play a significant role in drug resistance, immunological modulation, metastasis, and tumor proliferation. In this work, the differential miRNAs in the exosomes of drug-resistant and susceptible breast cancer cell lines were screened using miRNA-seq. It was demonstrated that drug-resistant human breast cancer cells and their exosomes expressed more miR-99b-3p than did susceptible cells and their exosomes. While drug-resistant cells' migration and paclitaxel resistance can be inhibited by driving down the expression of miR-99b-3p in those cells, exosomes containing miR-99b-3p from those cells can help susceptible cells migrate and become resistant. miR-99b-3p affects cell migration and paclitaxel resistance by targeting PPP2CA to promote AKT/mTOR phosphorylation. The drug-resistant cell exosome miR-99b-3p can be taken up by macrophages and affect the drug resistance and migration ability of sensitive cells by promoting the M2 polarization of macrophages. Downregulating miR-99b-3p has been shown in vivo to reverse macrophage M2 polarization, suppress tumor development, and prevent treatment resistance. The present study shows that drug-resistant cell exosomes miR-99b-3p can directly influence the migration, proliferation, and paclitaxel sensitivity of sensitive cells via PPP2CA. Additionally, the exosomes from drug-resistant cells can influence the polarization of macrophage M2 in the tumor microenvironment, which can also have an impact on the proliferation, migration, and paclitaxel sensitivity of sensitive cells.

LncRNA HIF1A-AS2 promotes triple-negative breast cancer progression and paclitaxel resistance via MRPS23 protein.

Dysregulation of lncRNAs is a critical factor in the migration and invasion of tumors. Here our study reveals that lncRNA HIF1A-AS2 is highly expressed in breast cancer tissues and various TNBC cell lines. Moreover, we present compelling evidence supporting the role of HIF1A-AS2 in promoting TNBC cell proliferation, metastasis, invasion, and resistance to paclitaxel treatment. Additionally, our transcriptome sequencing analysis identifies MRPS23 as a potential downstream target protein regulated by HIF1A-AS2 and knockdown of HIF1A-AS2 leads to decreased expression of MRPS23 in TNBC cells. Moreover, MRPS23 exhibits similar effects on enhancing cell proliferation, metastasis, invasion, and paclitaxel resistance in TNBC cells. Furthermore, downregulating HIF1A-AS2 suppresses the enhanced functionality observed in TNBC cells due to upregulated MRPS23 expression. These findings suggest that modulation of MRPS23 protein expression by HIF1A-AS2 may influence cellular processes and paclitaxel sensitivity in TNBC cells.

miR-141-3p promotes paclitaxel resistance by attenuating ferroptosis via the Keap1-Nrf2 signaling pathway in breast cancer.

Purpose: Breast cancer poses a huge threat to the lives and health of women worldwide. However, drug resistance makes the treatment of breast cancer challenging. This study aims to investigate the effect of miR-141-3p on paclitaxel resistance and its underlying mechanisms in breast cancer. Methods: Using bioinformatics analysis and qRT-PCR to explore the potential molecule miR-141-3p. Specific binding of miR-141-3p to Keap1 was determined by using a dual luciferase reporter assay. qRT-PCR and Western blot were utilized to observe the expression of miR-141-3p, Keap1, Nrf2, SLC7A11 and GPX4. GSH/GSSG content, MDA content and JC-1 assays were used to observe the ferroptosis levels of breast cancer cells. CCK-8 assay was used to observe the cell viability of breast cancer cells. Tumor subcutaneous transplantation experiment was used to understand the effect of miR-141-3p on paclitaxel resistance in breast cancer in vivo. Results: In the present study, miR-141-3p was found to be highly expressed and associated with poor prognosis in breast cancer. miR-141-3p inhibited Keap1 expression, promoted Nrf2 expression, and facilitated paclitaxel resistance in breast cancer cells. Inhibition of miR-141-3p promoted Keap1 expression, inhibited Nrf2 and its downstream SLC7A11-GSH-GPX4 signaling pathway, as well as promoted ferroptosis in cancer cells, and inhibited paclitaxel and RSL3 resistance. ML385 blocks the effect of miR-141-3p on paclitaxel resistance and ferroptosis resistance in breast cancer cells. In vivo, miR-141-3p mimics promoted paclitaxel resistance, whereas miR-141-3p inhibitors inhibited paclitaxel resistance in breast cancer cells. Conclusion: This work revealed that modulation of the Keap1-Nrf2 signaling pathway by miR-141-3p promoted paclitaxel resistance via regulating ferroptosis in breast cancer cells.

Targeting RAC1 reactivates pyroptosis to reverse paclitaxel resistance in ovarian cancer by suppressing P21-activated kinase 4.

Pyroptosis may play an important role in the resistance of ovarian cancer (OC) to chemotherapy. However, the mechanism by which pyroptosis modulation can attenuate chemotherapy resistance has not been comprehensively studied in OC. Here, we demonstrated that RAS-associated C3 botulinum toxin substrate 1 (RAC1) is highly expressed in OC and is negatively correlated with patient outcomes. Through cell function tests and in vivo tumor formation tests, we found that RAC1 can promote tumor growth by mediating paclitaxel (PTX) resistance. RAC1 can mediate OC progression by inhibiting pyroptosis, as evidenced by high-throughput automated confocal imaging, the release of lactate dehydrogenase (LDH), the expression of the inflammatory cytokines IL-1ß/IL-18 and the nucleotide oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. Mechanically, RNA-seq, gene set enrichment analysis (GSEA), coimmunoprecipitation (Co-IP), mass spectrometry (MS), and ubiquitination tests further confirmed that RAC1 inhibits caspase-1/gasdermin D (GSDMD)-mediated canonical pyroptosis through the P21-activated kinase 4 (PAK4)/mitogen-activated protein kinase (MAPK) pathway, thereby promoting PTX resistance in OC cells. Finally, the whole molecular pathway was verified by the results of in vivo drug combination tests, clinical specimen detection and the prognosis. In summary, our results suggest that the combination of RAC1 inhibitors with PTX can reverse PTX resistance by inducing pyroptosis through the PAK4/MAPK pathway.

Paclitaxel-resistance facilitates glycolytic metabolism via Hexokinase-2-regulated ABC and SLC transporter genes in ovarian clear cell carcinoma.

Ovarian clear cell carcinoma (OCCC) frequently develops resistance to platinum-based therapies, which is regarded as an aggressive subtype. However, metabolic changes in paclitaxel resistance remain unclear. Herein, we present the metabolic alternations of paclitaxel resistance in bioenergetic profiling in OCCC. Paclitaxel-resistant OCCC cells were developed and metabolically active with oxygen consumption rates (OCR) compared to parental cells. Metabolite profiling analysis revealed that paclitaxel-resistant OCCC cells reduced intracellular ATP and GTP influx rates, increasing the NADH/NAD+ ratio. We further demonstrated that paclitaxel-resistant OCCC cells led to characteristic alternations of metabolite levels in energy-requiring and energy-releasing steps of glycolysis and their corresponding glycolytic enzymes. Copy number alterations and RNA sequencing analysis demonstrated that ATP-binding cassette (ABC) transporters and solute carrier (SLC) transporter genes involved in glycolysis metabolism and molecular transport were enriched in paclitaxel-resistant OCCC cells. We first identified that Hexokinase 2 (HK2) expression is upregulated in paclitaxel-resistant OCCC cells to determine the quantity of glucose entering glycolysis. Utilizing proteolysis-targeting chimera (PROTAC) HK2 degraders, we also found that paclitaxel sensitivity, viability, and oxygen consumption rates under paclitaxel treatment were restored by HK2 degraders treatment, and decreased downstream expression of the ABC and SLC transporters was shown in OCCC cells. Taken together, these findings highlight the paclitaxel resistance in OCCC elucidates metabolic alternation, including ABC- and SLC- drug transporters, thereby affecting glycolysis metabolism in response to paclitaxel resistance, and HK2 may become a novel potential therapeutic target for paclitaxel resistance.

Oncogenic tRNA-derived fragment tRF-Leu-CAG promotes tumorigenesis of lung cancer via targeting TCEA3 and increasing autophagy.

BACKGROUND: Lung cancer is a prevalent and severe form of malignant tumors worldwide. tRF-Leu-CAG, a recently discovered non-coding single-stranded small RNA derived from transfer RNA, has sparked interest in exploring its biological functions and potential molecular mechanisms in lung cancer. METHODS: The abundance of tRF-Leu-CAG was measured via quantitative real-time polymerase chain reaction (qRT-PCR) in 96 sets of lung cancer tissue samples obtained from clinical patients. Subsequently, both in vivo and in vitro experiments were conducted to validate the biological functions of tRF-Leu-CAG in lung cancer. Furthermore, an exploration of the potential target genes of tRF-Leu-CAG and its association with autophagy and drug resistance in lung cancer was undertaken. RESULTS: Our analysis revealed a significant upregulation of tRF-Leu-CAG in non-small cell lung cancer (NSCLC) tissues. Additionally, we observed that heightened expression of tRF-Leu-CAG significantly augmented the proliferation and migration of NSCLC cells, facilitated cell cycle progression, and suppressed apoptosis. Furthermore, we identified transcription elongation factor A3 (TCEA3) as a direct target gene of tRF-Leu-CAG. TCEA3 inhibited the proliferation and migration of NSCLC, and tRF-Leu-CAG promoted the proliferation and migration of NSCLC by mediating the silencing of TCEA3. Moreover, we demonstrated that the augmentation of paclitaxel resistance by tRF-Leu-CAG was contingent on autophagy. Finally, tRF-Leu-CAG notably accelerated tumor growth and promoted the process of epithelial-mesenchymal transition (EMT) in vivo. CONCLUSIONS: tRF-Leu-CAG promotes NSCLC tumor growth and metastasis by targeting TCEA3 and promotes paclitaxel resistance by enhancing cellular autophagy. These results provide potentially effective targets and therapeutic options for the clinical treatment of NSCLC.

Integrated analysis of single-cell and bulk RNA-sequencing identifies a signature based on drug response genes to predict prognosis and therapeutic response in ovarian cancer.

Ovarian cancer represents a severe gynecological malignancy with a dire prognosis, underscoring the imperative need for dependable biomarkers that can accurately predict drug response and guide therapeutic choices. In this study, we harnessed online single-cell RNA sequencing (scRNAseq) and bulk RNA sequencing (RNAseq) datasets, applying the Scissor algorithm to identify cells responsive to paclitaxel. From these cells, we derived a gene signature, subsequently used to construct a prognostic model that demonstrated high sensitivity and specificity in predicting patient outcomes. Moreover, we conducted pathway and functional enrichment analyses to uncover potential molecular mechanisms driving the prognostic gene signature. This study illustrates the critical role of scRNAseq and bulk RNAseq in developing precise prognostic models for ovarian cancer, potentially transforming clinical decision-making.

Elemene Injection Overcomes Paclitaxel Resistance in Breast Cancer through AR/RUNX1 Signal: Network Pharmacology and Experimental Validation.

BACKGROUND: Paclitaxel (PTX) is a cornerstone chemotherapy for Breast Cancer (BC), yet its impact is limited by emerging resistance. Elemene Injection (EI) has shown potential in overcoming chemotherapy resistance. However, the efficacy by which EI restores PTX sensitivity in BC and the implicated molecular mechanism remain uncharted. METHODS: Network pharmacology and bioinformatic analysis were conducted to investigate the targets and mechanisms of EI in overcoming PTX resistance. A paclitaxel-resistant MCF-7 cell line (MCF-7PR) was established. The efficacy of EI and/or PTX in inhibiting cell viability was evaluated using sulforhodamine B assay, while cell proliferation was assessed using EdU staining. Furthermore, protein and gene expression analysis was performed through Western blotting and qPCR. RESULTS: The EI containing three active components exhibited a multifaceted impact by targeting an extensive repertoire of 122 potential molecular targets. By intersecting with 761 differentially expressed genes, we successfully identified 9 genes that displayed a direct association with resistance to PTX in BC, presenting promising potential as therapeutic targets for the EI to effectively counteract PTX resistance. Enrichment analysis indicated a significant correlation between these identified targets and critical biological processes, particularly DNA damage response and cell cycle regulation. This correlation was further substantiated through meticulous analysis of single-cell datasets. Molecular docking analysis revealed robust binding affinities between the active components of the EI and the identified molecular targets. Subsequently, in vitro experiments unequivocally demonstrated the dose- and time-dependent inhibitory effects of the EI on both PTX-resistant and sensitive BC cell lines, effectively mitigating the resistance phenotype associated with PTX administration. Furthermore, our findings have indicated EI to effectively suppress the protein expression levels of AR and RUNX1 in MCF-7 and MCF-7PR cells under PTX treatment, as well as downregulate the mRNA expression levels of stem-like properties' markers, KLF4 and OCT4, in these cell lines. CONCLUSION: Elemene Injection (EI) application has exhibited a significant capability to mitigate PTX resistance in BC, which has been achieved through targeted suppression of the AR/RUNX1 axis, revealing a key strategy to overcome chemotherapeutic resistance.

Deguelin Restores Paclitaxel Sensitivity in Paclitaxel-Resistant Ovarian Cancer Cells via Inhibition of the EGFR Signaling Pathway.

Background: Ovarian cancer is one of women's malignancies with the highest mortality among gynecological cancers. Paclitaxel is used in first-line ovarian cancer chemotherapy. Research on paclitaxel-resistant ovarian cancer holds significant clinical importance. Methods: Cell viability and flow cytometric assays were conducted at different time and concentration points of deguelin and paclitaxel treatment. Immunoblotting was performed to assess the activation status of key signaling molecules important for cell survival and proliferation following treatment with deguelin and paclitaxel. The fluo-3 acetoxymethyl assay for P-glycoprotein transport activity assay and cell viability assay in the presence of N-acetyl-L-cysteine were also conducted. Results: Cell viability and flow cytometric assays demonstrated that deguelin resensitized paclitaxel in a dose- and time-dependent manner. Cotreatment with deguelin and paclitaxel inhibited EGFR and its downstream signaling molecules, including AKT, ERK, STAT3, and p38 MAPK, in SKOV3-TR cells. Interestingly, cotreatment with deguelin and paclitaxel suppressed the expression level of EGFR via the lysosomal degradation pathway. Cotreatment did not affect the expression and function of P-glycoprotein. N-acetyl-L-cysteine failed to restore cell cytotoxicity when used in combination with deguelin and paclitaxel in SKOV3-TR cells. The expression of BCL-2, MCL-1, and the phosphorylation of the S155 residue of BAD were downregulated. Moreover, inhibition of paclitaxel resistance by deguelin was also observed in HeyA8-MDR cells. Conclusion: Our research showed that deguelin effectively suppresses paclitaxel resistance in SKOV3-TR ovarian cancer cells by downregulating the EGFR and its downstream signaling pathway and modulating the BCL-2 family proteins. Furthermore, deguelin exhibits inhibitory effects on paclitaxel resistance in HeyA8-MDR ovarian cancer cells, suggesting a potential mechanism for paclitaxel resensitization that may not be cell-specific. These findings suggest that deguelin holds promise as an anticancer therapeutic agent for overcoming chemoresistance in ovarian cancer.

ANGPTL3 diminishes the resistance of ovarian cancer to paclitaxel by blocking the PI3K-AKT-mTOR signaling pathway.

Angiopoietin-like protein 3 (ANGPTL3) is key in ovarian cancer (OC) cell growth and metastasis, notably by enhancing natural killer cells' capacity for inducing cell toxicity and apoptosis. However, its role in influencing chemotherapy resistance in OC remains ambiguous. In this study, we discovered a correlation between reduced ANGPTL3 levels and a less favorable outcome in OC patients using the Kaplan-Meier Plotter database. Lower levels of ANGPTL3 were detected in paclitaxel (PTX)-resistant OC tissues and cell lines via western blotting and immunohistochemistry. To investigate ANGPTL3's effects, we established SKOV3/PTX and 2780/PTX as PTX-resistant OC cell lines by incrementally increasing PTX exposure and then transfecting them with overexpress ANGPTL3 (OE-ANGPTL3) lentivirus. We conducted various assays such as CCK-8, colony formation, Edu staining, flow cytometry, and transwell to investigate the impact of ANGPTL3 on PTX resistance. Additionally, this effect was examined in a mouse subcutaneous xenograft model. Both in vitro and in vivo experiments demonstrated that ANGPTL3 overexpression mitigated PTX resistance in OC cells by inactivating the PI3K-AKT-mTOR pathway. In summary, our research reveals that ANGPTL3 enhances PTX sensitivity in OC by downregulating the PI3K-AKT-mTOR pathway. The study of this study suggest that ANGPTL3 could serve as a valuable therapeutic target for OC, signifying its clinical relevance in OC management.

Exosome-Mediated Transfer of ALDH2 in Nasopharyngeal Carcinoma Cells Confers Increased Resistance to Paclitaxel Treatment.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is an aggressive and highly metastatic malignant tumor. Despite recent therapeutic advances, resistance to Taxol (the generic name of paclitaxel) therapy remains a major challenge in clinical management. Therefore, it is imperative to explore the potential mechanisms of paclitaxel resistance in NPC. This study aimed to investigate the expression of aldehyde dehydrogenase 2 (ALDH2) in NPC cells and its critical role in paclitaxel resistance. METHODS: Paclitaxel-resistant cell line CNE1/Taxol (CNE1-TR), a drug-resistant cell line, was established by exposing the CNE1 nasopharyngeal carcinoma cell line to progressively increasing concentrations of paclitaxel. Furthermore, we investigated the role of ALDH2 in paclitaxel resistance and the function of exosomes using cell culture, Western blotting, reverse transcription-polymerase chain reaction (RT-PCR), Cell Counting Kit-8 (CCK-8), and nanoparticle tracking analysis. RESULTS: The results showed that in the presence of paclitaxel, the CNE1-TR cells manifested higher survival rate and half-maximal inhibitory concentration (IC50) value compared to the parental cell line, indicating strong resistance to paclitaxel. CNE1-TR cells had significantly upregulated mRNA and protein levels of ALDH2. In addition, exosome analysis showed that CNE1-TR cells were able to deliver ALDH2 via exosomes, increasing paclitaxel resistance in the recipient cells. We observed that the ALDH2 expression levels and paclitaxel resistance in CNE1-TR cells were effectively reduced by blocking the release of exosomes. CONCLUSION: ALDH2 is not only a key molecular marker indicative of therapeutic efficacy, but also a potential therapeutic target for developing novel anticancer strategies. By blocking the exosomal transport of ALDH2 or directly inhibiting its activity, it may be possible to overcome paclitaxel resistance, thus improving the success rate of clinical treatment.

CircRNA_0044556 affects the sensitivity of triple-negative breast cancer cells to paclitaxel by regulating miR-665.

CircRNAs have been implicated in the development of resistance in triple-negative breast cancer (TNBC). However, the association between circRNA_0044556 and paclitaxel (PTX) resistance in TNBC is still limited. Therefore, the purpose of this study was to investigate the effect of circRNA_0044556 on biological function and PTX resistance in TNBC cells. PTX-resistant TNBC cells (MDA-MB-231/PTX) were obtained by continuously exposing MDA-MB-231 cells to increasing paclitaxel levels. The expression levels of circRNA_0044556 and miR-665 were measured by qRT-PCR. The regulatory relationship between miR-665 and circRNA_0044556 was verified by biological information website analysis and double-luciferase reporter gene detection experiments. MTT assay, clone assay, flow cytometry and Western blot analysis were used to evaluate the influence of cell biological function. Elevated circRNA_0044556 was observed in TNBC, and paclitaxel increased the expression of circRNA_0044556 in TNBC cells. In TNBC, circRNA_0044556 acted as a ceRNA for miR-665. In addition, low expression of circRNA_0044556 combined with miR-665 inhibited the proliferation of TNBC cells and paclitaxel-resistant TNBC cells while inducing cell death. Our study demonstrated that the downregulation of circRNA_0044556 inhibits the malignant progression of TNBC cells and paclitaxel resistance via miR-665. Thus, circRNA_0044556 may be a potential therapeutic target for PTX-resistance TNBC.

Bioinformatics approach combined with experimental verification reveals OAS3 gene implicated in paclitaxel resistance in head and neck cancer.

BACKGROUND: This study aimed to identify a candidate gene associated with paclitaxel (PTX) resistance and to evaluate functionally its biological role in the PTX-resistant head and neck squamous cell carcinoma (HNSCC) cell lines and clinical specimens. METHODS: Microarray data series containing samples of different types of cancers resistant to PTX were analyzed and then a candidate gene associated with PTX resistance was identified using various bioinformatics tools. After the suppression of the target gene expression, changes in cell viability and colony-forming ability were evaluated in PTX-resistant FaDu and SCC-9 cell lines. RESULTS: Bioinformatics analyses of upregulated genes in PTX-resistant cancer cells indicated that OAS3 was associated with PTX resistance. The downregulation of OAS3 expression significantly reduced the viability and colony-forming capacity of PTX-resistant SCC-9 cells by inducing apoptosis and cell cycle arrest at G0/G1 phase. CONCLUSIONS: The therapeutic targeting of OAS3 may resensitize PTX-resistant HNSCC cells with high OAS3 expression to PTX treatment.

Corrigendum: Sesquiterpene lactones attenuate paclitaxel resistance via inhibiting MALAT1/STAT3/ FUT4 axis and P-Glycoprotein transporters in lung cancer cells.

[This corrects the article DOI: 10.3389/fphar.2022.795613.].

CCAAT enhancer binding protein delta activates vesicle associated membrane protein 3 transcription to enhance chemoresistance and extracellular PD-L1 expression in triple-negative breast cancer.

BACKGROUND: Chemoresistance and immunosuppression are two major obstacles in the current anti-cancer treatments. This study investigates the involvements of a CCAAT enhancer binding protein delta (CEBPD)/vesicle associated membrane protein 3 (VAMP3) axis in paclitaxel (PTX) resistance and immune evasion in triple-negative breast cancer (TNBC). METHODS: PTX resistance-related genes were screened by bioinformatics. CEBPD and VAMP3 expression in clinical TNBC samples was examined by immunohistochemistry. Three PTX-resistant TNBC cell lines (MDA-MB-231/PTX, MDA-MB-468/PTX and MDA-MB-453/PTX) were generated, and their drug resistance was analyzed. Autophagy of cells was analyzed by immunofluorescence staining. Interaction between CEBPD and VAMP3 promoter was identified by immunoprecipitation and luciferase assays. The extracellular expression of programmed cell death-ligand 1 (PD-L1) in TNBC cells was detected. Extracellular vesicles (EVs) from TNBC cells were isolated to examine their effects on CD8+ T cell exhaustion. RESULTS: CEBPD and VAMP3 were upregulated in chemo-resistant tissue samples and in PTX-resistant TNBC cells. The CEBPD downregulation enhanced PTX sensitivity of cells. However, further upregulation of VAMP3 in cells restored PTX resistance, which was likely due to the activation of autophagy, as the autophagy antagonist chloroquine enhanced PTX sensitivity of cells. CEBPD was found to bind to the VAMP3 promoter to activate its transcription. The CEBPD/VAMP3 axis also increased the PD-L1 expression in the conditioned medium of TNBC cells. The TNBC cell-derived EVs increased the exhaustion of co-cultured CD8+ T cells. CONCLUSION: This study provides novel evidence that CEBPD plays a key role in enhancing PTX resistance in TNBC cells across various subtypes through VAMP3-mediated autophagy activation. Additionally, the CEBPD/VAMP3 axis also increases extracellular PD-L1 level, delivered by cancer cell-derived EVs, to suppress CD8+ T cell-mediated anti-tumor immune response. These significant observations may provide new insights into the treatment of TNBC, suggesting CEBPD and VAMP3 as promising targets to overcome treatment resistance.

Crocin enhances the sensitivity to paclitaxel in human breast cancer cells by reducing BIRC5 expression.

Paclitaxel (PTX) is one of the first-line chemotherapeutic agents for treating breast cancer. However, PTX resistance remains a major hurdle in breast cancer therapy. Crocin, the main chemical constituent of saffron, shows anti-cancer activity against various types of cancer. However, the effect of crocin on the resistance of PTX in breast cancer is still unknown. CCK-8 and TUNEL assays were employed to detect cell viability and apoptosis, respectively. The targets of crocin were predicted using HERB database and the targets associated with breast cancer were acquired using GEPIA database. The Venn diagram was utilized to identify the common targets between crocin and breast cancer. Baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5) expression was detected by qRT-PCR and western blot analysis. The correlation between BIRC5 expression and survival was analyzed by Kaplan-Meier plotter and PrognoScan databases. Our data suggested that crocin aggravated PTX-induced decrease of viability and increase of apoptosis in MCF-7 and MCF-7/PTX cells. BIRC5 was identified as the target of crocin against breast cancer. Crocin inhibited BIRC5 expression in MCF-7 and MCF-7/PTX cells. BIRC5 is overexpressed in breast cancer tissues, as well as PTX-sensitive and PTX-resistant breast cancer cells. BIRC5 expression is related to the poor survival of patients with breast cancer. Depletion of BIRC5 strengthened PTX-induced viability reduction and promotion of apoptosis in MCF-7 and MCF-7/PTX cells. Moreover, BIRC5 overexpression reversed the inhibitory effect of crocin on PTX resistance in breast cancer cells. In conclusion, crocin enhanced the sensitivity of PTX in breast cancer cells partially through inhibiting BIRC5 expression.

WP1066, a small molecule inhibitor of STAT3, chemosensitizes paclitaxel-resistant ovarian cancer cells to paclitaxel by simultaneously inhibiting the activity of STAT3 and the interaction of STAT3 with Stathmin.

Paclitaxel is widely used to treat cancer, however, drug resistance limits its clinical utility. STAT3 is constitutively activated in some cancers, and contributes to chemotherapy resistance. Currently, several STAT3 inhibitors including WP1066 are used in cancer clinical trials. However, whether WP1066 reverses paclitaxel resistance and the mechanismremains unknown. Here, we report that in contrast to paclitaxel-sensitive parental cells, the expressions of several pro-survival BCL2 family members such as BCL-2, BCL-XL and MCL-1 are higher in paclitaxel-resistant ovarian cancer cells. Meanwhile, STAT3 is constitutively activated while stathmin loses its activity in paclitaxel-resistant cells. Importantly, WP1066 amplifies the inhibition of cell proliferation, colony-forming ability and apoptosis of ovarian cancer cells induced by paclitaxel. Mechanistically, WP1066, on the one hand, interferes the STAT3/Stathmin interaction, causing unleash of STAT3/Stathmin from microtubule, thus destroying microtubule stability. This process results in reduction of Ac-α-tubulin, further causing MCL-1 reduction. On the other hand, WP1066 inhibits phosphorylation of STAT3 by JAK2, and blocks its nuclear translocation, therefore repressing the transcription of pro-survival targets such as BCL-2, BCL-XL and MCL-1. Finally, the two pathways jointly promote cell death. Our findings reveal a new mechanism wherein WP1066 reverses paclitaxel-resistance of ovarian cancer cells by dually inhibiting STAT3 activity and STAT3/Stathmin interaction, which may layfoundation for WP1066 combined with paclitaxel in treating paclitaxel-resistant ovarian cancer.

MUC1-EGFR crosstalk with IL-6 by activating NF-κB and MAPK pathways to regulate the stemness and paclitaxel-resistance of lung adenocarcinoma.

BACKGROUND: The chemotherapy resistance often leads to chemotherapy failure. This study aims to explore the molecular mechanism by which MUC1 regulates paclitaxel resistance in lung adenocarcinoma (LUAD), providing scientific basis for future target selection. METHODS: The bioinformatics method was used to analyse the mRNA and protein expression characteristics of MUC1 in LUAD. RT-qPCR and ELISA were used to detect the mRNA and protein expression, flow cytometry was used to detect CD133+ cells, and cell viability was detected by CCK-8 assay. The mRNA-seq was performed to analyse the changes in expression profile, GO and KEGG analysis were used to explore the potential biological functions. RESULTS: MUC1 is highly expressed in LUAD patients and is associated with a higher tumour infiltration. In paclitaxel resistance LUAD cells (A549/TAX cells), the expression of MUC1, EGFR/p-EGFR and IL-6 were higher than that of A549 cells, the proportion of CD133+ cells was significantly increased, and the expression of cancer stem cell (CSCs) transcription factors (NANOG, OCT4 and SOX2) were significantly up-regulated. After knocking down MUC1 in A549/Tax cells, the activity of A549/Tax cells was significantly decreased. Correspondingly, the expression of EGFR, IL-6, OCT4, NANOG, and SOX2 were significantly down-regulated. The mRNA-seq showed that knocking down MUC1 affected the gene expression, DEGs mainly enriched in NF-κB and MAPK signalling pathway. CONCLUSION: MUC1 was highly expressed in A549/TAX cells, and MUC1-EGFR crosstalk with IL-6 may be due to the activation of NF-κB and MAPK pathways, which promote the enrichment of CSCs and lead to paclitaxel resistance.

Alpha-hederin reprograms multi-miRNAs activity and overcome small extracellular vesicles-mediated paclitaxel resistance in NSCLC.

Background: Small extracellular vesicles (sEVs) mediate intercellular communication in the tumor microenvironment (TME) and contribute to the malignant transformation of tumors, including unrestricted growth, metastasis, or therapeutic resistance. However, there is a lack of agents targeting sEVs to overcome or reverse tumor chemotherapy resistance through sEVs-mediated TME reprogramming. Methods: The paclitaxel (PTX)-resistant A549T cell line was used to explore the inhibitory effect of alpha-hederin on impeding the transmission of chemoresistance in non-small cell lung cancer (NSCLC) through the small extracellular vesicles (sEVs) pathway. This investigation utilized the CCK-8 assay and flow cytometry. Transcriptomics, Western blot, oil red O staining, and targeted metabolomics were utilized to evaluate the impact of alpha-hederin on the expression of signaling pathways associated with chemoresistance transmission in NSCLC cells before and after treatment. In vivo molecular imaging and immunohistochemistry were conducted to assess how alpha-hederin influences the transmission of chemoresistance through the sEVs pathway. RT-PCR was employed to examine the expression of miRNA and lncRNA in response to alpha-hederin treatment. Results: The resistance to PTX chemotherapy in A549T cells was overcome by alpha-hederin through its dependence on sEV secretion. However, the effectiveness of alpha-hederin was compromised when vesicle secretion was blocked by the GW4869 inhibitor. Transcriptomic analysis for 463 upregulated genes in recipient cells exposed to A549T-derived sEVs revealed that these sEVs enhanced TGFß signaling and unsaturated fatty acid synthesis pathways. Alpha-hederin inhibited 15 types of unsaturated fatty acid synthesis by reducing the signaling activity of the sEVs-mediated TGFß/SMAD2 pathway. Further, we observed that alpha-hederin promoted the production of three microRNAs (miRNAs, including miR-21-5p, miR-23a-3p, and miR-125b-5p) and the sorting to sEVs in A549T cells. These miRNAs targeted the TGFß/SMADs signaling activity in sEVs-recipient cells and sensitized them to the PTX therapy. Conclusion: Our finding demonstrated that alpha-hederin could sensitize PTX-resistant NSCLC cells by sEV-mediated multiple miRNAs accumulation, and inhibiting TGFß/SMAD2 pathways in recipient cells.

Non-coding RNA-related FCGBP downregulation in head and neck squamous cell carcinoma: a novel biomarker for predicting paclitaxel resistance and immunosuppressive microenvironment.

In head and neck squamous cell carcinoma (HNSC), chemoresistance is a major reason for poor prognosis. Nevertheless, there is a lack of validated biomarkers to screen for patients for categorical chemotherapy. Fc gamma binding protein (FCGBP) is a mucus protein associated with mucosal epithelial cells and has immunological functions that protect against tumors and metastasis. However, the effect of FCGBP on HNSC is unclear. In pan-cancer tissues, the expression of FCGBP and the survival status of patients were analyzed using information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Correlation analysis and Cox regression analysis were conducted to confirm the relationship and survival outcome. Bioinformatics analysis was utilized to predict the probable upstream non-coding RNA. FCGBP functioned as a potential tumor suppressor gene in HNSC. Notably, FCGBP expression was negatively correlated with enriched tumor-infiltrating macrophages and paclitaxel resistance. Cox regression with gene, clinical, and immune factors showed that FCGBP was a risk factor acting in an independent manner. In HNSC, the utmost possibly upstream non-coding RNA-related pathway of FCGBP was also discovered to be the PART1/AC007728.2/LINC00885/hsa-miR-877-5p/FCGBP axis. According to the present study, non-coding RNA-related low levels of FCGBP are a prognostic indicator and are linked to an HNSC-related immunosuppressive state.