MicroRNA-34a inhibits cell invasion and epithelial-mesenchymal transition via targeting AXL/PI3K/AKT/Snail signaling in nasopharyngeal carcinoma

Context-Dependent Regulation of Peripheral Nerve Abundance by the PI3K Pathway in the Tumor Microenvironment of Head and Neck Squamous Cell Carcinoma

Recent studies have highlighted neurons and their associated Schwann cells (SCs) as key regulators of cancer development. However, the mode of their interaction with tumor cells or other components of the tumor microenvironment (TME) remains elusive. We established an SC-related 43-gene set as a surrogate for peripheral nerves in the TME. Head and neck squamous cell carcinoma (HNSCC) from The Cancer Genome Atlas (TCGA) were classified into low, intermediate and high SC score groups based on the expression of this gene set. Perineural invasion (PNI) and TGF-β signaling were hallmarks of SChigh tumors, whereas SClow tumors were enriched for HPV16-positive OPSCC and higher PI3K-MTOR activity. The latter activity was partially explained by a higher frequency of PTEN mutation and PIK3CA copy number gain. The inverse association between PI3K-MTOR activity and peripheral nerve abundance was context-dependent and influenced by the TP53 mutation status. An in silico drug screening approach highlighted the potential vulnerabilities of HNSCC with variable SC scores and predicted a higher sensitivity of SClow tumors to DNA topoisomerase inhibitors. In conclusion, we have established a tool for assessing peripheral nerve abundance in the TME and provided new clinical and biological insights into their regulation. This knowledge may pave the way for new therapeutic strategies and impart proof of concept in appropriate preclinical models.

FZKA reverses gefitinib resistance by regulating EZH2/Snail/EGFR signaling pathway in lung adenocarcinoma

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzheng Kang-Ai (FZKA) decoction is mainly composed of 12 components with different types of herbs. In the last decade, FZKA has been used as an adjuvant treatment for lung cancer in clinical practice. Our previous studies have confirmed that FZKA shows a strong anti-cancer activity, significantly increases the clinical efficacy of gefitinib and reverses gefitinib resistance in non-small cell lung cancer (NSCLC). However, the molecular mechanism still needs to be further elucidated.

AIM OF THE STUDY

The aim of this study was to investigate the role and mechanism by which FZKA inhibited the cell growth, proliferation and invasion of lung adenocarcinoma(LUAD) and reversed the acquired resistance of gefitinib for the therapy in LUAD.

MATERIALS AND METHODS

Cell viability assay and EDU assay were used for detecting of cell viability and cell proliferation. Transwell assay was performed to measure cell invasion. Western Blot and qRT-PCR were used for protein and gene expression test. The gene promoter activity was determined by dul-luciferase reporter assay. The in situ expression of protein was measured by cell immunofluorescence. Stabilized cell lines were established for stable overexpression of EZH2. Transient transfection assay was used for gene silence and overexpression. Xenograft tumors and bioluminescent imaging were used for in vivo experiments.

RESULTS

FZKA significantly inhibited the cell viability, proliferation and cell invasion of LUAD, the combination of FZKA and gefitinib had a great synergy on the above processes. Moreover, FZKA significantly decreased EZH2 mRNA and protein expression, FZKA reversed the resistance of gefitinib by down-regulation of EZH2 protein. ERK1/2 kinase mediated the down-regulation of EZH2 reduced by FZKA. In addition, FZKA decreased the expression of Snail and EGFR by decreasing EZH2. Overexpression of Snail and EGFR significantly reversed the effect of FZKA-inhibited cell invasion and cell proliferation. More important, the combination of FZKA and gefitinib enhanced the inhibitory effect on EZH2, Snail and EGFR proteins. Furthermore, the growth inhibition and reversal of gefitinib resistance induced by FZKA were further validated in vivo. Finally, the expression and clinical correlation of EZH2,EGFR and Snail in cancer patients were further validated using bioinformatics analysis.

CONCLUSIONS

FZKA significantly suppressed tumor progression and reversed gefitinib resistance by regulating the p-ERK1/2-EZH2-Snail/EGFR signaling pathway in LUAD.

MiR-34a functions as a tumor suppressor in oral cancer through the inhibition of the Axl/Akt/GSK-3β pathway

Background/purpose

Oral cancer is a prevalent malignancy affecting men globally. This study aimed to investigate the regulatory role of miR-34a in oral cancer cells through the Axl/Akt/glycogen synthase kinase-3β (GSK-3β) pathway and its impact on cellular malignancy.

Materials and methods

We examined the effects of miR-34a overexpression on the malignancy of oral cancer cells. Multiple oral cancer cell lines were assessed to determine the correlation between endogenous miR-34a and Axl levels. Transfection experiments with miR-34a were conducted to analyze its influence on Axl mRNA and protein expression. Luciferase reporter assays were performed to investigate miR-34a's modulation of Axl gene transcription. Manipulation of miR-34a expression was utilized to demonstrate its regulatory effects on oral cancer cells through the Axl/Akt/GSK-3β pathway.

Results

Overexpression of miR-34a significantly suppressed the malignancy of oral cancer cells. We observed an inverse correlation between endogenous miR-34a and Axl levels across multiple oral cancer cell lines. Transfection of miR-34a resulted in decreased Axl mRNA and protein expression, and luciferase reporter assays confirmed miR-34a-mediated modulation of Axl gene transcription. The study revealed regulatory effects of miR-34a on oral cancer cells through the Axl/Akt/GSK-3β pathway, leading to alterations in downstream target genes involved in cellular proliferation and tumorigenesis.

Conclusion

Our findings highlight the significance of the miR-34a/Axl/Akt/GSK-3β signaling axis in modulating the malignancy of oral cancer cells. Targeting miR-34a may hold therapeutic potential in oral cancer treatment, as manipulating its expression can attenuate the aggressive behavior of oral cancer cells via the Axl/Akt/GSK-3β pathway.

Triple‑negative breast cancer cells that survive ionizing radiation exhibit an Axl‑dependent aggressive radioresistant phenotype

This study aimed to investigate the aggressive behavior of triple-negative breast cancer (TNBC) cells that had survived ionizing radiation and explore the potential targets of TNBC combination treatment. Consistent with the previous literature, Axl was highly expressed in TNBC and closely associated with the degree of malignancy based on immunohistochemical staining. Using a gradient irradiation method, the ionizing radiation-resistant mouse TNBC cell line 4T-1/IRR was established. It was found that Axl expression was upregulated in 4T-1/IRR cells. After irradiation by X-ray, the cell viability and colony formation ability of 4T-1/IRR cells were significantly increased when compared with the 4T-1 cells. Combined radiotherapy with Axl inhibition by treatment with R428 and small interfering RNA lentivirus targeting Axl infection significantly reduced cell viability, colony formation ability, DNA double-stranded break repair, and the invasive and migratory ability of 4T-1/IRR cells. In vivo, the small animal radiation research platform was applied to precisely administer radiotherapy of the tumor-bearing mice. R428 treatment combined with 6 Gy X-ray significantly inhibited the growth of 4T-1/IRR cells-derived xenograft tumors in the BALB/c mouse. The results of western blotting showed that the critical molecular mechanism involved in the radioresistance of TNBC cells was the PI3K/Akt/mTOR signaling pathway induced by Axl activation. Thus, it is hypothesized that targeted Axl therapy combined with radiotherapy may have significant potential for the treatment of TNBC.

Promising Biomarkers in Head and Neck Cancer: The Most Clinically Important miRNAs

Head and neck cancers (HNCs) comprise a heterogeneous group of tumors that extend from the oral cavity to the upper gastrointestinal tract. The principal etiologic factors for oral tumors include tobacco smoking and alcohol consumption, while human papillomavirus (HPV) infections have been accused of a high incidence of pharyngeal tumors. Accordingly, HPV detection has been extensively used to categorize carcinomas of the head and neck. The diverse nature of HNC highlights the necessity for novel, sensitive, and precise biomarkers for the prompt diagnosis of the disease, its successful monitoring, and the timely prognosis of patient clinical outcomes. In this context, the identification of certain microRNAs (miRNAs) and/or the detection of alterations in their expression patterns, in a variety of somatic fluids and tissues, could serve as valuable biomarkers for precision oncology. In the present review, we summarize some of the most frequently studied miRNAs (including miR-21, -375, -99, -34a, -200, -31, -125a/b, -196a/b, -9, -181a, -155, -146a, -23a, -16, -29, and let-7), their role as biomarkers, and their implication in HNC pathogenesis. Moreover, we designate the potential of given miRNAs and miRNA signatures as novel diagnostic and prognostic tools for successful patient stratification. Finally, we discuss the currently ongoing clinical trials that aim to identify the diagnostic, prognostic, or therapeutic utility of miRNAs in HNC.

Small biomarkers with massive impacts: PI3K/AKT/mTOR signalling and microRNA crosstalk regulate nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignant tumours of the head and neck in Southeast Asia and southern China. The Phosphatidylinositol 3-kinase/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway is involved in processes related to tumour initiation/progression, such as proliferation, apoptosis, metastasis, and drug resistance, and is closely related to the clinicopathological features of NPC. In addition, key genes involved in the PI3K/AKT/mTOR signalling pathway undergo many changes in NPC. More interestingly, a growing body of evidence suggests an interaction between this signalling pathway and microRNAs (miRNAs), a class of small noncoding RNAs. Therefore, in this review, we discuss the interactions between key components of the PI3K/AKT/mTOR signalling pathway and various miRNAs and their importance in NPC pathology and explore potential diagnostic biomarkers and therapeutic targets.

Circ_0028007 Aggravates the Malignancy of Nasopharyngeal Carcinoma by Regulating miR-656-3p/ELF2 Axis

Circular RNAs function as important regulators in the pathogenesis of human cancers, including nasopharyngeal carcinoma (NPC). We aimed to explore the functions of circ_0028007 in NPC development. Quantitative real-time polymerase chain reaction assay was employed for the levels of circ_0028007, NUAK family kinase 1, microRNA-656-3p (miR-656-3p), and E74 like ETS transcription factor 2 (ELF2). RNase R assay was used to verify the feature of circ_0028007. Cell Counting Kit-8 assay and colony formation assay were performed to assess cell growth. Wound-healing assay and transwell assay were adopted to analyze cell migration and invasion. Tube formation assay was conducted for cell angiogenic capacity. Flow cytometry analysis was performed for cell apoptosis. Western blot assay was conducted for protein levels. Compared to normal tissues and cells, circ_0028007 level was elevated in NPC tissues and cells. Knockdown of circ_0028007 repressed NPC cell growth, migration, invasion, and angiogenesis, facilitated apoptosis in vitro and blocked tumor growth in vivo. Moreover, circ_0028007 silencing could regulate the AMP-activated protein kinase/mammalian target of rapamycin pathway in NPC cells. Circ_0028007 promoted the malignant behaviors of NPC cells via acting as miR-656-3p sponge. In addition, ELF2 was demonstrated to be the target gene of miR-656-3p. MiR-656-3p overexpression restrained NPC cell malignant phenotypes, while ELF2 elevation reversed the effects. Circ_0028007 contributed to the progression of NPC by decoying miR-656-3p and elevating ELF2. The findings might provide potential targets for NPC therapy.

Crosstalk between miRNA and PI3K/AKT/mTOR signaling pathway in cancer

Phosphoinositide-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important proliferative signaling pathways with critical undeniable function in various aspects of cancer initiation/progression, including proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. On the other hand, numerous genetic alterations in the key genes involved in the PI3K/AKT/mTOR signaling pathway have been identified in multiple solid and hematological tumors. In addition, accumulating recent evidences have demonstrated a reciprocal interaction between this signaling pathway and microRNAs, a large group of small non-coding RNAs. Therefore, in this review, it was attempted to discuss about the interaction between key components of PI3K/AKT/mTOR signaling pathway with various miRNAs and their importance in cancer biology.

Dysregulated tumor-associated macrophages in carcinogenesis, progression and targeted therapy of gynecological and breast cancers

Gynecological and breast cancers are a group of heterogeneous malignant tumors. Although existing treatment strategies have ameliorated the clinical outcomes of patients, the overall survival rate of advanced diseases remains unsatisfactory. Increasing evidence has indicated that the development and prognosis of tumors are closely related to the tumor microenvironment (TME), which restricts the immune response and provokes malignant progression. Tumor-associated macrophages (TAMs) are the main component of TME and act as a key regulator in tumor metastasis, immunosuppression and therapeutic resistance. Several preclinical trials have studied potential drugs that target TAMs to achieve potent anticancer therapy. This review focuses on the various functions of TAMs and how they influence the carcinogenesis of gynecological and breast cancers through regulating cancer cell proliferation, tumor angiogenesis and tumor-related immunosuppression. Besides, we also discuss the potential application of disabling TAMs signaling as a part of cancer therapeutic strategies, as well as CAR macrophages, TAMs-based vaccines and TAMs nanobiotechnology. These research advances support that targeting TAMs combined with conventional therapy might be used as effective therapeutics for gynecological and breast cancers in the future.

New insight towards development of paclitaxel and docetaxel resistance in cancer cells: EMT as a novel molecular mechanism and therapeutic possibilities

Epithelial-to-mesenchymal transition (EMT) mechanism is responsible for metastasis and migration of cancer cells to neighboring cells and tissues. Morphologically, epithelial cells are transformed to mesenchymal cells, and at molecular level, E-cadherin undergoes down-regulation, while an increase occurs in N-cadherin and vimentin levels. Increasing evidence demonstrates role of EMT in mediating drug resistance of cancer cells. On the other hand, paclitaxel (PTX) and docetaxel (DTX) are two chemotherapeutic agents belonging to taxene family, capable of inducing cell cycle arrest in cancer cells via preventing microtubule depolymerization. Aggressive behavior of cancer cells resulted from EMT-mediated metastasis can lead to PTX and DTX resistance. Upstream mediators of EMT such as ZEB1/2, TGF-β, microRNAs, and so on are involved in regulating response of cancer cells to PTX and DTX. Tumor-suppressing factors inhibit EMT to promote PTX and DTX sensitivity of cancer cells. Furthermore, three different strategies including using anti-tumor compounds, gene therapy and delivery systems have been developed for suppressing EMT, and enhancing cytotoxicity of PTX and DTX against cancer cells that are mechanistically discussed in the current review.

Circular dumbbell miR-34a-3p and -5p suppresses pancreatic tumor cell-induced angiogenesis and activates macrophages

Angiogenesis is a tightly regulated biological process by which new blood vessels are formed from pre-existing blood vessels. This process is also critical in diseases such as cancer. Therefore, angiogenesis has been explored as a drug target for cancer therapy. The future of effective anti-angiogenic therapy lies in the intelligent combination of multiple targeting agents with novel modes of delivery to maximize therapeutic effects. Therefore, a novel approach is proposed that utilizes dumbbell RNA (dbRNA) to target pathological angiogenesis by simultaneously targeting multiple molecules and processes that contribute to angiogenesis. In the present study, a plasmid expressing miR-34a-3p and -5p dbRNA (db34a) was constructed using the permuted intron-exon method. A simple protocol to purify dbRNA from bacterial culture with high purity was also developed by modification of the RNASwift method. To test the efficacy of db34a, pancreatic cancer cell lines PANC-1 and MIA PaCa-2 were used. Functional validation of the effect of db34a on angiogenesis was performed on human umbilical vein endothelial cells using a tube formation assay, in which cells transfected with db34a exhibited a significant reduction in tube formation compared with cells transfected with scrambled dbRNA. These results were further validated in vivo using a zebrafish angiogenesis model. In conclusion, the present study demonstrates an approach for blocking angiogenesis using db34a. The data also show that this approach may be used to targeting multiple molecules and pathways.

LukS-PV Inhibits Hepatocellular Carcinoma Cells Migration via the TNNC1/PI3K/AKT Axis

Purpose

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. LukS-PV is the S component of Panton-Valentine leucocidin (PVL), a toxin secreted by Staphylococcus aureus. We aimed to investigate the role of LukS-PV in HCC cell migration and the specific molecular mechanism involved.

Methods

We used scratch assays to detect the mobility of liver cancer cells treated with LukS-PV. Quantitative real-time PCR and Western blot analysis were performed to detect the expression levels of related genes. RNA sequencing and quantitative proteomics sequencing were used to assess the transcriptional and proteomic alterations of target genes. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) pathway analyses revealed the downstream signaling pathway targets of LukS-PV.

Results

Our results demonstrated that LukS-PV could inhibit HCC cell migration in a concentration-dependent manner. LukS-PV could also downregulate the expression of TNNC1, which was highly expressed in HCC cells. Additionally, the study showed that LukS-PV inhibited HCC cell migration by downregulating TNNC1. Further studies showed that LukS-PV inhibited the phosphorylation of PI3K/AKT pathway by targeting TNNC1, thereby inhibiting HCC cell migration.

Conclusion

Our study demonstrated that LukS-PV has an inhibitory role in the migration of liver cancer cells through the TNNC1/PI3K/AKT axis.