Hypoxia and aberrant activation of epidermal growth factor receptor (EGFR) are considered important features of various malignancies. However, whether hypoxia can directly trigger EGFR activation and its clinical implications remain unclear. In this study, we demonstrated that in oral cancer, a typical hypoxic tumor, hypoxia can induce chronic but constitutive phosphorylation of wild-type EGFR in the absence of ligands. Oral cancer cell lines exhibit different EGFR phosphorylation responses to hypoxia. In hypoxic HN4 and HN6 cells, ubiquitination-mediated endocytosis, lysosomal sorting, and degradation lead to low levels of EGFR phosphorylation. However, in CAL-27 and HN30 cells, a novel HIF-1α-induced long noncoding RNA (lncRNA), EUDAL, can compete with the E3 ligase/adaptor complex c-Cbl/Grb2 for binding to EGFR, stabilizing phosphorylated EGFR (pEGFR) and resulting in sustained activation of EGFR and its downstream STAT3/BNIP3 signaling. STAT3/BNIP3-mediated autophagy leads to antitumor drug resistance. A high EUDAL/EGFR/STAT3/autophagy pathway activation predicts poor response to chemotherapy in oral cancer patients. Collectively, hypoxia can induce noncanonical ligand-independent EGFR phosphorylation. High EUDAL expression facilitates sustained EGFR phosphorylation in hypoxic tumor cells and leads to autophagy-related drug resistance.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/pathology* ; RNA, Long Noncoding/genetics* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor ; Phosphorylation ; Signal Transduction ; STAT3 Transcription Factor/metabolism* ; Cell Hypoxia ; Autophagy ; Proto-Oncogene Proteins c-cbl/metabolism*

The transcription factor HOXB13 plays crucial roles in cancer development. HOXB13 is abnormally expressed in most cancers, which makes it a valuable therapeutic target for cancer therapy. The level of HOXB13 differs significantly between healthy and cancer tissues, which indicates that the level of HOXB13 is closely related to carcinogenesis. The regulatory network mediated by HOXB13 in cancer proliferation, metastasis, and invasion has been systematically investigated. Moreover, HOXB13 variants play distinct roles in different cancers and populations. By understanding the molecular mechanisms and mutation features of HOXB13, we provide a comprehensive overview of carcinogenesis networks dependent on HOXB13. Finally, we discuss advancements in anticancer therapy targeting HOXB13 and the roles of HOXB13 in drug resistance to molecular-targeted therapies, which serves as a foundation for developing HOXB13-targeted drugs for clinical diagnosis and cancer therapies.
Humans ; Neoplasms/metabolism* ; Homeodomain Proteins/metabolism* ; Carcinogenesis/genetics* ; Mutation ; Gene Expression Regulation, Neoplastic ; Molecular Targeted Therapy ; Drug Resistance, Neoplasm/genetics*

Cancer multidrug resistance (MDR) impairs the therapeutic efficacy of various chemotherapeutics. Novel approaches, particularly the development of MDR reversal agents, are critically needed to address this challenge. This study demonstrates that tenacissoside I (TI), a compound isolated from Marsdenia tenacissima (Roxb.) Wight et Arn, traditionally used in clinical practice as an ethnic medicine for cancer treatment, exhibits significant MDR reversal effects in ABCB1-mediated MDR cancer cells. TI reversed the resistance of SW620/AD300 and KBV200 cells to doxorubicin (DOX) and paclitaxel (PAC) by downregulating ABCB1 expression and reducing ABCB1 drug transport function. Mechanistically, protein arginine methyltransferase 1 (PRMT1), whose expression correlates with poor prognosis and shows positive association with both ABCB1 and EGFR expressions in tumor tissues, was differentially expressed in TI-treated SW620/AD300 cells. SW620/AD300 and KBV200 cells exhibited elevated levels of EGFR asymmetric dimethylarginine (aDMA) and enhanced PRMT1-EGFR interaction compared to their parental cells. Moreover, TI-induced PRMT1 downregulation impaired PRMT1-mediated aDMA of EGFR, PRMT1-EGFR interaction, and EGFR downstream signaling in SW620/AD300 and KBV200 cells. These effects were significantly reversed by PRMT1 overexpression. Additionally, TI demonstrated resistance reversal to PAC in xenograft models without detectable toxicities. This study establishes TI's MDR reversal effect in ABCB1-mediated MDR human cancer cells through inhibition of PRMT1-mediated aDMA of EGFR, suggesting TI's potential as an MDR modulator for improving chemotherapy outcomes.
Humans ; Protein-Arginine N-Methyltransferases/antagonists & inhibitors* ; Drug Resistance, Neoplasm/drug effects* ; ErbB Receptors/genetics* ; Animals ; Cell Line, Tumor ; Drug Resistance, Multiple/drug effects* ; Methylation/drug effects* ; Saponins/administration & dosage* ; Mice ; Mice, Nude ; Mice, Inbred BALB C ; ATP Binding Cassette Transporter, Subfamily B/genetics* ; Doxorubicin/pharmacology* ; Paclitaxel/pharmacology* ; Female ; Repressor Proteins

Objective To study the impacts of curcumin on the proliferation, migration and cisplatin (DDP) resistance of bladder cancer cells by regulating the liver kinase B1-AMP activated protein kinase-microtubule-associated protein 1 light chain 3 (LKB1-AMPK-LC3) signaling pathway. Methods Human bladder cancer cell line T24 was cultured in vitro, and its DDP resistant T24/DDP cells were induced by cisplatin (DDP). After treating T24 and T24/DDP cells with different concentrations of curcumin, the optimal concentration of curcumin was screened by MTT assay. T24 cells were randomly grouped into control group, curcumin group, metformin group, and combination group of curcumin and metformin. After treatment with curcumin and LKB1-AMPK activator metformin, the proliferation, autophagy, migration, and apoptosis of T24 cells in each group were detected by MTT assay, monodansylcadavrine (MDC) fluorescence staining, cell scratch assay, and flow cytometry, respectively. Western blot was used to detect the expression of proteins related to LKB1-AMPK-LC3 signaling pathway in T24 cells of each group. T24/DDP cells were randomly assigned into control group, curcumin group, metformin group, and combination group of curcumin and metformin. Cells were treated with curcumin and metformin according to grouping and treated with different concentrations of DDP simultaneously. Then, the effect of curcumin on the DDP resistance coefficient of T24/DDP cells was detected by MTT assay. T24/DDP cells were randomly grouped into control group, DDP group, combination groups of DDP and curcumin, DDP and metformin, DDP, curcumin and metformi. After treatment with DDP, curcumin, and metformin, the proliferation, autophagy, migration, apoptosis, drug resistance, and the expression of proteins related to LKB1-AMPK-LC3 signaling pathway in T24/DDP cells of each group were detected with the same methods. Results Compared with the control group, the activity of T24 cells, relative number of autophagosomes, migration rate, Phosphorylated-LKB1 (p-LKB1)/LKB1, Phosphorylated-AMPK (p-AMPK)/AMPK, LC3II/LC3I, and the DDP resistance coefficient of T24/DDP cells in the curcumin group were lower, and the apoptosis rate of T24 cells was higher; the changes in various indicators in the metformin group were opposite to those in the curcumin group. Compared with the curcumin group, the activity of T24 cells, relative number of autophagosomes, migration rate, p-LKB1/LKB1, p-AMPK/AMPK, LC3II/LC3I, and the DDP resistance coefficient of T24/DDP cells in the combination group of curcumin and metformin were higher, and the apoptosis rate of T24 cells was lower. Compared with the control group, there were no obvious changes in various indicators of T24/DDP cells in the DDP group. Compared with the control group and DDP group, the viability of T24/DDP cells, relative number of autophagosomes, migration rate, P-glycoprotein (P-gp) protein expression, p-LKB1/LKB1, p-AMPK/AMPK, and LC3II/LC3I in the combination group of DDP and curcumin were lower, and the apoptosis rate of T24/DDP cells was higher; the changes in the above indicators in the combination group of DDP and metformin were opposite to those in the combination group of DDP and curcumin. Compared with the combination group of DDP and curcumin, the viability of T24/DDP cells, relative number of autophagosomes, migration rate, P-gp protein expression, p-LKB1/LKB1, p-AMPK/AMPK, and LC3II/LC3I in the combination group of DDP, curcumin and metformin were higher, and the apoptosis rate of T24/DDP cells was lower. Conclusion Curcumin can reduce the activity of LKB1-AMPK-LC3 signaling pathway, thereby inhibiting autophagy, proliferation and migration of bladder cancer cells, promoting their apoptosis, and weakening their resistance to DDP.
Humans ; Cisplatin/pharmacology* ; Curcumin/pharmacology* ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects* ; Protein Serine-Threonine Kinases/genetics* ; AMP-Activated Protein Kinases/metabolism* ; Drug Resistance, Neoplasm/drug effects* ; Urinary Bladder Neoplasms/pathology* ; Cell Line, Tumor ; Cell Movement/drug effects* ; AMP-Activated Protein Kinase Kinases ; Microtubule-Associated Proteins/metabolism* ; Apoptosis/drug effects* ; Antineoplastic Agents/pharmacology* ; Metformin/pharmacology* ; Autophagy/drug effects*

It has been popular and challenging to undertake researches on the delay of acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI). As key cells for tumor initiation, cancer stem cells (CSC) play an important role in the process of resistance to EGFR-TKI. Although preliminary studies found that traditional Chinese medicine (TCM) could inhibit CSC properties and delay EGFR-TKI resistance, the specific molecular mechanism remains unclear. By summarizing the empirical syndrome treatment of EGFR-TKI resistance via TCM and combining recent researches on TCM intervention in CSC to delay EGFR-TKI resistance, this review discussed the potential molecular pathways and mechanisms of deceleration in resistance to EGFR-TKI by TCM via inhibiting CSC characteristics, in order to expand the research ideas of TCM in combination with targeted therapy.
Humans ; Neoplastic Stem Cells/metabolism* ; Drug Resistance, Neoplasm/drug effects* ; ErbB Receptors/genetics* ; Protein Kinase Inhibitors/therapeutic use* ; Medicine, Chinese Traditional ; Neoplasms/drug therapy* ; Animals ; Drugs, Chinese Herbal/therapeutic use*

Objective The aim of this study was to investigate the effect of p38 on stem cell maintenance of pancreatic cancer. Methods Human pancreatic cancer cells PANC-1 were treated with different concentrations of 5-fluorouracil(5-FU)(0.5×IC₅₀, IC₅₀, and 2×IC₅₀) for 24 hours, and VX-702 (p38 phosphorylation inhibitor) was added, and the cells were inoculated in 6-well culture dishes with ultra-low adhesion to observe the changes of sphere tumors. The expression levels of cyclin-dependent kinase 2(CDK2), cyclin B1 and D1, Octamer-binding transcription factor 4(OCT4), SRY-box transcription factor 2(SOX2), Nanog and p38 were measured by Western blot. The mRNA expression levels of p38, OCT4, Nanog and SOX2 were tested by RT-PCR. Cell cycle, apoptosis, and the proportion of CD44⁺CD133⁺PANC-1 cells were evaluated by flow cytometry. Results The results showed that 5-FU inhibited the formation of tumor spheres in PANC-1 cells, increased CD44⁺CD133⁺cell fragments, down-regulated the expression of OCT4, Nanog and SOX2, and inhibited the stemness maintenance of PANC-1 tumor stem cells. Phosphorylation of PANC-1 cells was inhibited by a highly selective p38 MAPK inhibitor, VX-702(p38 mitogen-activated protein kinase inhibitor), which had the same effect as 5-FU treatment. When VX-702 combined with 5-FU was used to treat PANC-1 cells, the therapeutic effect was enhanced. Conclusion p38 inhibitors decreased PANC-1 cell activity and increased cell apoptosis. p38 inhibitors inhibit the stemness maintenance of pancreatic cancer stem cells.
Humans ; Phosphorylation/drug effects* ; Cell Line, Tumor ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors* ; Neoplastic Stem Cells/metabolism* ; Drug Resistance, Neoplasm/drug effects* ; Fluorouracil/pharmacology* ; Pancreatic Neoplasms/pathology* ; Apoptosis/drug effects* ; SOXB1 Transcription Factors/genetics* ; Octamer Transcription Factor-3/genetics*

Immune checkpoint inhibitors (ICIs) have become the cornerstone of treatment for driver gene-negative advanced non-small cell lung cancer (NSCLC). However, resistance is inevitable, and the underlying mechanisms remain incompletely understood. Histological transformation is a rare but emerging cause of acquired resistance to immunotherapy, with only sporadic case reports documented to date. Here, we report the first case of lung adenocarcinoma that underwent histological transformation to atypical carcinoid following first-line therapy with ICIs combined with chemotherapy, highlighting the critical role of histological lineage switching in mediating NSCLC resistance to ICIs. Notably, the patient harbored a rearranged during transfection (RET) fusion mutation. Subsequent targeted therapy with Selpercatinib after histological transformation demonstrated favorable efficacy, suggesting a potential therapeutic strategy for atypical carcinoid patients with co-occurring rare driver mutations. This case provides a potential therapeutic option for atypical carcinoid patients with rare mutations.
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Humans ; Carcinoid Tumor/drug therapy* ; Carcinoma, Non-Small-Cell Lung/immunology* ; Drug Resistance, Neoplasm ; Immune Checkpoint Inhibitors/therapeutic use* ; Immunotherapy ; Lung Neoplasms/immunology* ; Oncogene Proteins, Fusion/genetics* ; Proto-Oncogene Proteins c-ret/genetics*

Non-small cell lung cancer (NSCLC) ranks among the most lethal malignancies worldwide. The clinical application of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have successfully revolutionized the treatment paradigm for EGFR-mutant NSCLC, significantly prolonging progression-free survival and establishing EGFR-TKIs as the standard first-line therapy for advanced lung adenocarcinoma. However, acquired resistance remains a major obstacle to sustained clinical benefit, with mechanisms that are highly heterogeneous. A phenomenon of "oxidative stress compensation" is commonly observed in EGFR-TKIs-resistant cells, where in redox homeostasis, through the precise regulation of reactive oxygen species (ROS) generation and elimination, plays a pivotal role in maintaining the balance between tumor cell proliferation and apoptosis. This review aims to innovatively construct a theoretical framework describing how dynamic redox regulation influences resistance to third-generation EGFR-TKIs. It focuses on the multifaceted roles of ROS in both EGFR-dependent and EGFR-independent resistance mechanisms, and further explores therapeutic strategies that target ROS kinetic thresholds and antioxidant systems. These insights not only propose an innovative "metabolic checkpoint" regulatory pathway to overcome acquired resistance to third-generation EGFR-TKIs, but also lay a molecular foundation for developing the redox biomarker-based dynamic therapeutic decision-making systems, thereby facilitating a shift in NSCLC therapy from single-target inhibition toward multi-dimensional metabolic remodeling in the context of precision medicine.
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Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; ErbB Receptors/genetics* ; Drug Resistance, Neoplasm/drug effects* ; Lung Neoplasms/genetics* ; Oxidation-Reduction/drug effects* ; Homeostasis/drug effects* ; Protein Kinase Inhibitors/therapeutic use* ; Reactive Oxygen Species/metabolism* ; Animals

BACKGROUND: Lung cancer currently ranks first globally in both incidence and mortality. Pemetrexed (PMX) serves as a first-line treatment for lung adenocarcinoma (LUAD), but the patients often develop drug resistance during therapy. Milk exosome (mEXO) have the advantages of low immunogenicity, high tissue affinity, and low cost, and mEXO itself has anti-tumor effects. Hyaluronan (HA) naturally bind to CD44, a receptor which is highly expressed in LUAD tissues. This study aims to construct hyaluronan-modified milk exosome (HA-mEXO) and preliminarily investigate their molecular mechanisms for reversing PMX resistance through cellular experiments. METHODS: Exosomes were extracted from milk using high-speed centrifugation, and HA-mEXO was constructed. PMX-resistant A549 and PC-9 cell lines were treated with mEXO and HA-mEXO, respectively. CCK-8 assays, colony formation assays, Transwell assays, and flow cytometry were performed to evaluate proliferation, colony formation, migration, invasion, and apoptosis phenotypes in the treated resistant cell lines. Finally, transcriptomic sequencing, analysis, and cellular functional recovery experiments were conducted to investigate the mechanism by which HA-mEXO reverses PMX resistance in LUAD cells. RESULTS: The expression of CD44 in A549 and PC-9 LUAD drug-resistant cell lines was significantly higher than that in parental cells, and the uptake rate of HA-mEXO by drug-resistant cell lines was significantly higher than that of mEXO. Compared to the mEXO group, HA-mEXO-treated A549 and PC-9 resistant cells exhibited significantly reduced half maximal inhibitory concentration (IC50) values for PMX, markedly diminished clonogenic, migratory, and invasive capabilities, and a significantly increased proportion of apoptotic cells. Western blot analysis revealed that, compared to parental cells, A549 and PC-9 drug-resistant cells exhibited downregulated ZNF516 expression and upregulated ABCC5 expression. Immunofluorescence analysis revealed that HA-mEXO treatment downregulated ABCC5 expression in A549 and PC-9 drug-resistant cells compared to the PBS group, whereas co-treatment with HA-mEXO and ZNF516 knockdown showed no significant change in ABCC5 expression. CONCLUSIONS HA-mEXO carrying ZNF516 suppress ABCC5 expression, thereby enhancing the sensitivity of A549 and PC-9 LAUD drug-resistant cells to PMX.
Humans ; Hyaluronic Acid/chemistry* ; Drug Resistance, Neoplasm/drug effects* ; Exosomes/chemistry* ; Adenocarcinoma of Lung/genetics* ; Pemetrexed/pharmacology* ; Animals ; Lung Neoplasms/pathology* ; Milk/chemistry* ; Cell Proliferation/drug effects* ; Apoptosis/drug effects* ; Cell Line, Tumor ; Hyaluronan Receptors/metabolism*

OBJECTIVES: Oxaliplatin (OXA) and 5-fluorouracil (5-FU) are 2 commonly used chemotherapeutic agents for colorectal cancer (CRC). MicroRNAs (miRNAs, miRs) play crucial roles in the development of chemoresistance in various cancers. However, the role and mechanism of miR-224-5p in regulating CRC chemoresistance remain unclear. This study aims to investigate the function of miR-224-5p in chemoresistant CRC cells and the underlying mechanisms. METHODS: CRC datasets GSE28702 and GSE69657 were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed miRNAs between drug-sensitive and resistant groups (OXA or 5-FU) were analyzed, and miR-224-5p was identified as the target miRNA. Chemoresistant cell lines HCT15-OXR, HCT15-5-FU, SW480-OXR, and SW480-5-FU were established. Transient transfections were performed using miR-224-5p mimics, inhibitors, and their respective negative controls (control mimic, control inhibitor) in these cell lines. Cells were treated with different concentrations of OXA or 5-FU post-transfection, and the half-maximal inhibitory concentration (IC₅₀) was determined using the cell counting kit-8 (CCK-8) assay. Cell proliferation was assessed by CCK-8 and colony formation assays. The expression levels of miR-224-5p, LC3, and P62 were measured by real-time polymerase chain reaction (real-time PCR) and/or Western blotting. Autophagic flux was assessed using a tandem fluorescent-tagged LC3 reporter assay. TargetScan 8.0, miRTarBase, miRPathDB, and HADb were used to predict B-cell lymphoma-2 (Bcl-2) as a potential miR-244-5p target, which was further validated by dual-luciferase reporter assays. RESULTS: Chemoresistant CRC cells exhibited down-regulated miR-224-5p expression, whereas up-regulation of miR-224-5p enhanced chemotherapy sensitivity. Exposure to OXA or 5-FU significantly increased autophagic activity in chemoresistant CRC cells, which was reversed by miR-224-5p overexpression. Dual-luciferase assays verified Bcl-2 as a direct target of miR-224-5p. CONCLUSIONS MiR-224-5p regulates chemoresistance in CRC by modulating autophagy through direct targeting of Bcl-2.
Humans ; MicroRNAs/physiology* ; Colorectal Neoplasms/drug therapy* ; Drug Resistance, Neoplasm/genetics* ; Autophagy/drug effects* ; Fluorouracil/pharmacology* ; Oxaliplatin ; Cell Line, Tumor ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Gene Expression Regulation, Neoplastic