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

OBJECTIVES: To investigate the effect of downregulation of medium-chain acyl-coenzyme A dehydrogenase (ACADM) on invasion and migration of estrogen receptor-positive breast cancer cells and the underlying mechanism. METHODS: The Kaplan-Meier Plotter database was used to analyze the ACADM expression levels in breast cancer and normal tissues and their association with patient prognosis. Human breast cancer MCF-7 and T47D cell lines with lentivirus-mediated ACADM knockdown were established, and their in situ tumor formation and metastasis after tail vein injection were evaluated in nude mice. The MCF-7 and T47D cells with ACADM knockdown and their unmodified parental cells were examined with oil-red O staining assay, ROS assay, mitochondrial respiratory chain function assay before and after treatments with ROS scavenger, Elamipretide (a cardiolipin oxidation inhibitor) or SC79 (an AKT activator), and the changes in migration and invasion abilities of the treated cells were analyzed with Transwell invasion assay and Boyden chamber assay. Western blotting was used to detect protein expression levels of related signaling pathways in the treated cells. RESULTS: ACADM overexpression was associated with a significantly shorter overall survival of breast cancer patients. In MCF-7 and T47D cells, ACADM knockdown resulted in downregulation of N calnexin, vimentin, p-P13K and p-AKT proteins, increased levels of free fatty acids and reactive oxygen species, lowered activities of mitochondrial respiratory chain complex III and V, and reduced mitochondrial inner phospholipids. ACADM knockdown significantly decreased the invasive capacity of the cells, which were obviously reversed by treatment with ROS scavenger, Elamipretide, and SC79. CONCLUSIONS Down-regulation of ACADM inhibits migration and invasion ability of estrogen receptor-positive breast cancer cells by lowering lipotoxicity and impairing mitochondrial function through the ROS/PI3K/AKT pathway.
Humans ; Breast Neoplasms/metabolism* ; Female ; Mice, Nude ; Down-Regulation ; Neoplasm Invasiveness ; Animals ; Mice ; Receptors, Estrogen/metabolism* ; MCF-7 Cells ; Cell Movement ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Acyl-CoA Dehydrogenase/genetics* ; Signal Transduction ; Neoplasm Metastasis ; Proto-Oncogene Proteins c-akt/metabolism*

OBJECTIVES: To study the effect of CDC20 knockdown on proliferation, migration and invasion of cervical cancer cells and its underlying mechanism. METHODS: CDC20 expression in cervical cancer tissues was analyzed using the TCGA database, and the protein expressions of CDC20 and β-Catenin in clinical specimens of cervical cancer and adjacent tissues were detected using immunohistochemistry. A dual target sgRNA2&7 sequence for CDC20 gene was designed for CDC20 gene knockdown in cervical cancer C33A cells using CRISPR/Cas9 technology, and CDC20 mRNA and protein expression levels in the transfected cells were detected using qRT-PCR and Western blotting. The changes in proliferation, cell cycle, apoptosis, migration and invasiveness of the transfected cells were evaluated using colony-forming assay, fluorescence activated cell sorting (FACS) and Transwell assay. In the animal experiment, naïve C33A cells and the cells with CDC20 knockdown were injected subcutaneously into the left and right axillae of nude mice (n=5) to observe tumor growth. The expressions of CDC20 and β-Catenin proteins in transfected cells and the xenograft were analyzed using Western blotting, and their interaction was confirmed by co-immunoprecipitation (CoIP) and immunofluorescence co-localization assays. RESULTS: Cervical cancer tissues expressed significantly higher CDC20 and β‑Catenin levels than the adjacent tissues. C33A cells with CDC20 knockdown showed reduced proliferation, increased apoptosis, and lowered migration and invasion abilities. CDC20 knockdown significantly suppressed the growth of C33A cell xenograft in nude mice, and the tumor-bearing mice did not exhibit obvious body mass changes. CDC20 and β-Catenin levels were both significantly lowered in C33A cells with CDC20 knockdown. Co-immunoprecipitation and co-localization assays confirmed the interaction between CDC20 and β‑Catenin. CONCLUSIONS CDC20 is highly expressed in cervical cancer tissues, and CDC20 knockdown can suppress proliferation, invasion, and metastasis while enhancing apoptosis of C33A cells, which is closely related with the regulation of the Wnt/β-Catenin signaling pathway.
Humans ; Uterine Cervical Neoplasms/metabolism* ; Female ; Cdc20 Proteins/genetics* ; Cell Proliferation ; Animals ; Cell Movement ; Neoplasm Invasiveness ; Apoptosis ; Mice, Nude ; beta Catenin/metabolism* ; CRISPR-Cas Systems ; Mice ; Cell Line, Tumor ; Gene Knockout Techniques ; Neoplasm Metastasis

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*

Loss of protein homeostasis is a hallmark of cellular senescence, and ribosome pausing plays a crucial role in the collapse of proteostasis. However, our understanding of ribosome pausing in senescent cells remains limited. In this study, we utilized ribosome profiling and G-quadruplex RNA immunoprecipitation sequencing techniques to explore the impact of RNA G-quadruplex (rG4) on the translation efficiency in senescent cells. Our results revealed a reduction in the translation efficiency of rG4-rich genes in senescent cells and demonstrated that rG4 structures within coding sequence can impede translation both in vivo and in vitro. Moreover, we observed a significant increase in the abundance of rG4 structures in senescent cells, and the stabilization of the rG4 structures further exacerbated cellular senescence. Mechanistically, the RNA helicase DHX9 functions as a key regulator of rG4 abundance, and its reduced expression in senescent cells contributing to increased ribosome pausing. Additionally, we also observed an increased abundance of rG4, an imbalance in protein homeostasis, and reduced DHX9 expression in aged mice. In summary, our findings reveal a novel biological role for rG4 and DHX9 in the regulation of translation and proteostasis, which may have implications for delaying cellular senescence and the aging process.
G-Quadruplexes ; Cellular Senescence ; Ribosomes/genetics* ; Humans ; Animals ; Mice ; DEAD-box RNA Helicases/genetics* ; Protein Biosynthesis ; RNA/chemistry* ; Neoplasm Proteins

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 explore the correlation between single nucleotide polymorphisms (SNPs) of ARID5B gene and the risk of acute lymphoblastic leukemia (ALL) and minimal residual disease (MRD) in children of Hui and Han nationality in Ningxia. METHODS: In this case-control study, 54 ALL children and control group with matched age, sex and nationality were detected for the polymorphism of ARID5B gene using fluorescence resonance energy transfer technique, and the susceptibility of different ALL genotypes and their correlation with MRD were analyzed. RESULTS: There were no significant differences in genotype and allele frequency of rs10994982, rs7089424, rs10740055, rs7073837, rs4245595 and rs7090445 between the two groups (P >0.05). At the locus of rs10821936, the frequencies of T/T genotype and T allele in ALL group were significantly higher than those in the control group (both P < 0.05). The C/C genotype of ARID5B gene SNP rs10821936 was a risk factor for early MRD positive in ALL children ( P < 0.05). CONCLUSION ARID5B gene SNP rs10821936 is related to the development of childhood ALL and MRD.
Humans ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics* ; Polymorphism, Single Nucleotide ; Case-Control Studies ; Neoplasm, Residual/genetics* ; DNA-Binding Proteins/genetics* ; Transcription Factors/genetics* ; Genotype ; Genetic Predisposition to Disease ; Gene Frequency ; Child ; Male ; Female ; Alleles ; Risk Factors ; Child, Preschool

BACKGROUND: Abnormalities of the switch/sucrose nonfermentable (SWI/SNF) chromatin-remodeling complex are closely related to various cancers, and ARID1B (AT-rich interaction domain 1B) is one of the core subunits of the SWI/SNF complex. Mutations or copy number deletions of the ARID1B gene are associated with impaired DNA damage response and altered chromatin accessibility. However, whether ARID1B deficiency affects the proliferation, migration and invasion abilities of non-small cell lung cancer (NSCLC) cells and its molecular mechanisms remain poorly understood. This study aims to reveal the regulatory role of ARID1B gene deletion on the malignant phenotype of NSCLC cells and its molecular mechanism. METHODS: Online databases were used to analyze the relationship between ARID1B and the prognosis of patients with lung cancer, and the expression levels of ARID1B in lung cancer tissues. The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeat) technology was employed to construct stable ARID1B gene knockout (KO) cell lines. The plate colony formation assay was used to detect cell proliferation, and the Transwell cell migration and invasion assays were used to detect changes in cell migration ability. RNA-Seq was utilized for the expression and enrichment analysis of differentially expressed genes. Western blot (WB) was used to verify the knockout effect of the ARID1B gene and to detect the expression changes of epithelial-mesenchymal transition (EMT) markers and mitogen-activated protein kinases (MAPK) signaling pathway-related proteins. Nude mouse tumor models were constructed and the tumorigenic abilities of control and ARID1B-deficient cells were compared. RESULTS: Patients with low ARID1B expression have poor overall survival. ARID1B is differentially expressed in lung cancer and normal tissues, and its expression level being lower in cancer cells. ARID1B-deficient cells had significantly enhanced in vitro proliferation, migration and invasion abilities. In animal experiments, the tumor formation speed of ARID1B gene deficient cells was significantly accelerated. Enrichment analysis of RNA-Seq results revealed that the differentially expressed genes were mainly enriched in MAPK, phosphoinositide 3-kinase-protein kinase B (PI3K/Akt) and other signaling pathways. WB experiments demonstrated that the expressions of E-cadherin, N-cadherin and Vimentin changed in ARID1B gene deficient cells, and the expressions of MAPK and p-MAPK was increased. CONCLUSIONS The A549-ARID1B KO and PC9-ARID1B KO cell lines were successfully established. The ARID1B-deficient cell lines demonstrated high migration, invasion and proliferation potential at both in vitro and in vivo biological behavior levels and at the transcriptome sequencing level. The changes in the expression of EMT markers and the activation of the MAPK signaling pathway suggest possible metastasis mechanisms of ARID1B-deficient NSCLC.
Humans ; Cell Proliferation/genetics* ; Cell Movement/genetics* ; Lung Neoplasms/metabolism* ; Animals ; Carcinoma, Non-Small-Cell Lung/physiopathology* ; Transcription Factors/metabolism* ; Neoplasm Invasiveness ; Mice ; DNA-Binding Proteins/metabolism* ; Gene Deletion ; Cell Line, Tumor ; Epithelial-Mesenchymal Transition ; Mice, Nude ; Gene Expression Regulation, Neoplastic

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*