MicroRNA-302c enhances the chemosensitivity of human glioma cells to temozolomide by suppressing P-gp expression

MiR-3664-3p through suppressing ABCG2, CYP3A4, MCL1, and MLH1 increases the sensitivity of colorectal cancer cells to irinotecan

Background

Colorectal cancer (CRC) is the third most frequently diagnosed malignancy worldwide. Currently, irinotecan (CPT-11) is used alone or in combination with other drugs to treat patients with advanced CRC. However, the 5-year survival rate for metastatic CRC remains below 10 %, largely due to chemotherapy resistance. Several genes, including ABCG2, CYP3A4, MCL1, and MLH1 contribute to irinotecan resistance. This study aimed to identify microRNAs that simultaneously regulate the expression of these genes in irinotecan-resistant cell lines and study their effect on resistant colorectal cancer cells.

Methods

Irinotecan-resistant colorectal cancer cell lines were developed by intermittently exposing HCT116 and SW480 cell lines to gradually increasing doses of irinotecan over four generations. These resistant cell lines were designated HCT116-R1, HCT116-R2, HCT116-R3, HCT116-R4 and SW480-R1, SW480-R2, SW480-R3, SW480-R4. The induction of resistance was confirmed using MTT assays, by calculating IC50 values for each generation and comparing them to the parental cells. The expression levels of the ABCG2, CYP3A4, MCL1, and MLH1 genes, along with miR-3664-3p, were initially measured in all resistant and parental cell lines using quantitative real-time PCR. Following transfection of HCT116-R3 and SW480-R3 cells with pre-miR-3664-3p, the expression levels of ABCG2, CYP3A4, MCL1, MLH1, and miR-3664-3p were re-evaluated using real-time PCR.

Results

In resistant cell lines derived from HCT116 and SW480, increased expression of the ABCG2, CYP3A4, and MCL1 genes was observed. However, a reduction in CYP3A4 expression was noted in the final resistant lines from both cell lines. Additionally, while MLH1 expression increased in HCT116-derived cell lines, no significant increase was observed in SW480-derived lines. A consistent decrease in miR-3664-3p expression was found across all resistant cell lines. When we transfected HCT116-R3 and SW480-R3 cells with pre-miR-3664-3p, there was an increase in miR-3664-3p expression and a reduction in ABCG2, CYP3A4, MCL1, and MLH1 gene expression. This led to increased sensitivity to irinotecan.

Conclusion

It can be concluded that miR-3664-3p can be considered a regulator of resistance to irinotecan by modulating the expression of ABCG2, CYP3A4, MCL1, and MLH1 genes.

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

Essential oil of Ligusticum chuanxiong Hort. Regulated P-gp protein and tight junction protein to change pharmacokinetic parameters of temozolomide in blood, brain and tumor

ETHNOPHARMACOLOGICAL RELEVANCE

The existence of the blood-brain barrier/blood tumor barrier (BBB/BTB) severely restricts the effectiveness of anti-tumor drugs, thus glioma is still an incurable disease with a high fatality rate. Chuanxiong (Ligusticum chuanxiong Hort., Umbelliferae) was used as a messenger drug to increase the distribution of drugs in brain tissue, and its application in Chinese herbal formula for treating glioma was also the highest.

AIM OF THE STUDY

Our previous researches showed that essential oil (EO) of chuanxiong could promote temozolomide (TMZ) entry into glioma cells in vitro and enhance TMZ-induced anticancer efficiency in vivo, and therefore, the aim of this study was to investigate whether EO could increase the concentration accumulation of TMZ in brain or tumor of C6 glioma rats and the related mechanisms.

MATERIALS AND METHODS

The pharmacokinetics were conducted in C6 glioma rats by administering either TMZ alone or combined with EO through oral routes. TMZ concentration in blood, brain and tumor was detected using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and then pharmacokinetic parameters were calculated. The changed expressions of P-gp protein, tight junction occludin, claudin-5 and zonula occludens-1 (ZO-1) in brain of glioma rats were studied by Western blot to clarify the mechanism. Finally, the chemical composition of EO was analyzed by gas chromatography-massspectrometry (GC-MS).

RESULTS

The results showed that EO significantly affected the pharmacokinetic parameters such as T_max, C_max and CL (p < 0.01), but did not significantly change the AUC_(0→∞) of TMZ in blood (p > 0.05). However, EO markedly improved the AUC_(0→∞)of TMZ in brain and tumor (p < 0.01). The calculate drug targeting index was greater than 1, indicating that EO could promote the distribution of TMZ to the brain and tumor. Western blot analysis showed that EO significantly inhibited the expression of P-gp, tight junction protein claudin-5, occludin and ZO-1. And meanwhile, the expressions of P-gp, claudin-5 and occludin also markedly down-regulated in EO-TMZ co-administration treatment. GC-MS analysis of the TIC component of EO was (E)-Ligustilide (36.93%), Terpinolene (7.245%), gamma-terpinene (7.225%) etc. CONCLUSION: EO could promote the distribution of TMZ in the brain and tumor of C6 glioma rats, which may attribute to down-regulate the expression of P-gp, claudin-5 and occludin.

Mechanism of RIP2 enhancing stemness of glioma cells induces temozolomide resistance

AIMS

We aimed to investigate the role of receptor-interacting protein 2 (RIP2) in regulation of stemness of glioma cells and chemotherapy resistance.

METHODS

Plasmid transfection was used to overexpress RIP2. Chemical inhibitors were used to inhibit RIP2 or NF-κB activity. Cancer stemness of glioma cells was investigated by sphere formation assays, clone formation assays, and xenograft tumor formation assays. The expression of RIP2, p-NF-κB, IκBα, CD133, or SOX-2 was detected by Western blotting and immunofluorescence. Apoptosis was detected by flow cytometry. Immunohistochemical staining was used to detect the expression of RIP2, CD133, and SOX-2 in xenograft tumor tissue. The effect of the RIP2/NF-κB pathway on temozolomide (TMZ) resistance was evaluated by xenograft tumor assay.

RESULTS

Transfection with RIP2 plasmid enhanced the sphere formation capability of U251 cells, clone formation capability, and xenograft tumor formation capability. RIP2 could mediate TMZ resistance by upregulating the expression of CD133 and SOX-2 by activating the NF-κB pathway. Both RIP2 inhibitor GSK583 and the NF-κB inhibitor SC75741 could reverse the resistance of U251 cells to TMZ.

CONCLUSION

RIP2 mediates TMZ resistance by regulating the maintenance of stemness in glioma cells through NF-κB. Interventions targeting the RIP2/NF-κB pathway may be a new strategy for TMZ-resistant gliomas.

Lemon-Derived Extracellular Vesicles Nanodrugs Enable to Efficiently Overcome Cancer Multidrug Resistance by Endocytosis-Triggered Energy Dissipation and Energy Production Reduction

Multidrug resistance remains a great challenge for cancer chemotherapy. Herein, a biomimetic drug delivery system based on lemon-derived extracellular vesicles (EVs) nanodrugs (marked with heparin-cRGD-EVs-doxorubicin (HRED)) is demonstrated, achieving highly efficient overcoming cancer multidrug resistance. The HRED is fabricated by modifying functional heparin-cRGD (HR) onto the surface of EVs and then by loading with doxorubicin (DOX). The obtained HRED enable to effectively enter DOX-resistant cancer cells by caveolin-mediated endocytosis (main), macropinocytosis (secondary), and clathrin-mediated endocytosis (last), exhibiting excellent cellular uptake capacity. The diversified endocytosis capacity of HRED can efficiently dissipate intracellular energy and meanwhile trigger downstream production reduction of adenosine triphosphate (ATP), leading to a significant reduction of drug efflux. Consequently, they show excellent anti-proliferation capacities to DOX-resistant ovarian cancer, ensuring the efficiently overcoming ovarian cancer multidrug resistance in vivo. The authors believe this strategy provides a new strategy by endocytosis triggered-energy dissipation and ATP production reduction to design drug delivery system for overcoming cancer multidrug resistance.

The Role of microRNAs in Multidrug Resistance of Glioblastoma

Glioblastoma (GBM) is an aggressive brain tumor that develops from neuroglial stem cells and represents a highly heterogeneous group of neoplasms. These tumors are predominantly correlated with a dismal prognosis and poor quality of life. In spite of major advances in developing novel and effective therapeutic strategies for patients with glioblastoma, multidrug resistance (MDR) is considered to be the major reason for treatment failure. Several mechanisms contribute to MDR in GBM, including upregulation of MDR transporters, alterations in the metabolism of drugs, dysregulation of apoptosis, defects in DNA repair, cancer stem cells, and epithelial-mesenchymal transition. MicroRNAs (miRNAs) are a large class of endogenous RNAs that participate in various cell events, including the mechanisms causing MDR in glioblastoma. In this review, we discuss the role of miRNAs in the regulation of the underlying mechanisms in MDR glioblastoma which will open up new avenues of inquiry for the treatment of glioblastoma.

NcRNAs: Multi‑angle participation in the regulation of glioma chemotherapy resistance (Review)

As the most common primary tumour of the central nervous system, gliomas have a high recurrence rate after surgical resection and are resistant to chemotherapy, particularly high‑grade gliomas dominated by glioblastoma multiforme (GBM). The prognosis of GBM remains poor despite improvements in treatment modalities, posing a serious threat to human health. At present, although drugs such as temozolomide, cisplatin and bevacizumab, are effective in improving the overall survival of patients with GBM, most patients eventually develop drug resistance, leading to poor clinical prognosis. The development of multidrug resistance has therefore become a major obstacle to improving the effectiveness of chemotherapy for GBM. The ability to fully understand the underlying mechanisms of chemotherapy resistance and to develop novel therapeutic targets to overcome resistance is critical to improving the prognosis of patients with GBM. Of note, growing evidence indicates that a large number of abnormally expressed noncoding RNAs (ncRNAs) have a central role in glioma chemoresistance and may target various mechanisms to modulate chemosensitivity. In the present review, the roles and molecular mechanisms of ncRNAs in glioma drug resistance were systematically summarized, the potential of ncRNAs as drug resistance markers and novel therapeutic targets of glioma were discussed and prospects for glioma treatment were outlined. ncRNAs are a research direction for tumor drug resistance mechanisms and targeted therapies, which not only provides novel perspectives for reversing glioma drug resistance but may also promote the development of precision medicine for clinical diagnosis and treatment.

Histone demethylase JMJD1C promotes the polarization of M1 macrophages to prevent glioma by upregulating miR-302a

Glioma is regarded as an aggressive lethal primary brain tumor. Jumonji domain containing 1C (JMJD1C) is a H3K9 demethylase which participates in the progression of various tumors, but its specific function and underlying mechanism in glioma development remain undefined, which is the purpose of our work. We initially assessed JMJD1C expression in glioma tissues and cells using the assays of RT-qPCR and immunohistochemistry. Meanwhile, the H3K9 level at the microRNA (miR)-302a promoter region was measured by chromatin immunoprecipitation assay, while luciferase-based reporter assay was performed for validation of the binding affinity between miR-302a and methyltransferase-like 3 (METTL3). The effect of METTL3 on suppressor of cytokine signaling 2 (SOCS2) was subsequently analyzed by MeRIP-RT-qPCR. Finally, a xenograft tumor model was established in nude mice, followed by measurement of tumor-associated macrophages using flow cytometry. JMJD1C was poorly expressed in glioma tissues. Furthermore, JMJD1C increased miR-302a expression through promoting H3K9me1 demethylation at the miR-302a promoter region. miR-302a was identified to target METTL3, which could inhibit SOCS2 expression via m6A modification. JMJD1C promoted M1 macrophage polarization and suppressed the growth of glioma xenografts through the miR-302a/METTL3/SOCS2 axis both in vivo and in vitro. In conclusion, JMJD1C could enhance M1 macrophage polarization to inhibit the onset of glioma, bringing a new insight into the contribution of JMJD1C to the pathobiology of glioma, with possible implications for targeted therapeutic method.

miR-23b-5p promotes the chemosensitivity of temozolomide via negatively regulating TLR4 in glioma

Glioma is the most common malignancy in the brain, with poor survival and often highly resistant to chemotherapy and radiotherapy. Temozolomide (TMZ) is an alkylating agent widely used for glioma treatment. However, resistance to TMZ results in treatment failure, while the underlying mechanisms remain unclear. Mounting evidence suggests that dysregulated microRNA (miRNA) expression plays a critical function in glioma development and resistance to TMZ treatment. In this study, we found that miR-23b-5p was downregulated in glioma tissues and cell lines. Overexpression of miR-23b-5p inhibited cell proliferation and promoted cell apoptosis in glioma cells, while miR-23b-5p enhanced the chemosensitivity of TMZ in glioma cells. Furthermore, we identified that Toll-like receptor 4 (TLR4) is a direct target of miR-23b-5p in glioma cells. Knockdown of TLR4 suppressed cell proliferation and enhanced cell apoptosis and promoted chemosensitivity to TMZ treatment in glioma cells. In addition, we demonstrated that overexpression of TLR4 abrogated the regulatory function of miR-23b-5p in glioma cells on cell proliferation, cell apoptosis, and the chemosensitivity of TMZ treatment. In summary, our data suggest that miR-23b-5p promotes the chemosensitivity of TMZ via negatively regulating TLR4 in glioma, which provides a new therapeutic strategy for TMZ-resistant glioma treatment.

Inhibition of MicroRNA-302c on Stemness of Colon Cancer Stem Cells via the CARF/Wnt/β-Catenin Axis

BACKGROUND

Even though the relevance of microRNA (miR)-302c has been studied, little is known about its involvement in colon cancer (CC).

AIMS

Our aim here was to investigate the role of miR-302c in the cancer stem cells (CSCs) of CC.

METHODS

Firstly, the CSCs were screened out from cultured SW1116 and SW480 cells by flow cytometry, and the differentially expressed miRNAs in cell were obtained by microarray analysis. The expression of miR-302c, collaborator of ARF (CARF), and Wnt/β-catenin-related genes in CSCs was determined by means of RT-qPCR and Western blot. A dual-luciferase reporter assay was conducted to authenticate the binding relationship between miR-302c and CARF. Proliferation, migration, invasion, sphere formation as well as apoptosis of CSCs were assessed by cell counting kit-8, Transwell assay, sphere formation assay as well as flow cytometric analysis, respectively. The roles of miR-302c and CARF in tumor growth were determined in vivo.

RESULTS

The expression of miR-302c in CC cells was reduced versus that in normal cells. The overexpression of miR-302c weakened the stemness, proliferation, invasion, and migration abilities while induced apoptosis of CSCs in CC. Also, miR-302c reduced tumor size and weight in mice, accompanied with lowered CARF expression. The mechanistic analysis manifested that miR-302c bound to CARF and suppressed its expression and disrupted the Wnt/β-catenin signaling.

CONCLUSION

This study offers a novel characterization of miR-302c function in CSCs in CC, which may be beneficial to the development of capable therapeutic options for CC.