MiR-221-3p-mediated downregulation of MDM2 reverses the paclitaxel resistance of non-small cell lung cancer in vitro and in vivo

Abstract

Background: MicroRNAs (miRNAs) are involved in the initiation and development of cancer, and participate in drug resistance. Paclitaxel (PTX) is rst-line chemotherapy drug for advanced non-small cell lung cancer (NSCLC). The abnormal miRNA expression in NSCLC and its association with chemotherapy drug resistance remains largely unknown. The study aimed to investigate the aberrant expression of miR-221-3p in NSCLC and to elucidate its molecular mechanisms in relation to PTX resistance. Methods: Quantitative polymerase chain reaction (qPCR) was used to examine miRNA and messenger RNA (mRNA) in NSCLC tissues and cell lines. The roles of miR-221-3p in NSCLC progression and drug resistance were assessed by Western blot analysis, colony formation assay, and CCK-8. Dual-luciferase reporter assay was conducted to evaluate the interaction between miR-221-3p and MDM2. Xenograft tumor models were established by subcutaneously injecting PTX-resistant A549 cells (A549/Taxol) to assess the effect of miR-221-3p on tumor growth. Data regarding miRNAs and target proteins from 20 NSCLC tissues and paired non-cancerous matched tissues were also obtained for correlation analysis. Results: PTX increased miR-221-3p expression, which regulated MDM2/P53 expression in the PTXsensitive NSCLC strain (A549). Meanwhile, miR-221-3p was rarely expressed and not interfered by PTX in A549/Taxol. Dual luciferase reporter assay con rmed that miR-221-3p speci cally binds to MDM2 mRNA. MiR-221-3p down-regulation reduced the sensitivity of A549 cells to PTX, whereas its up-regulation partially reversed the A549/Taxol cells resistance to PTX and increased the chemosensitivity of A549/Taxol cells to PTX in xenograft models. QPCR analysis revealed that miR-221-3p expression increased, whereas the MDM2 level decreased in NSCLC tumor tissues. Furthermore, the result of Western bolt analysis showed that P53 was lowly expressed in tumor tissues with MDM2 overexpression. Conclusions: MiR-221-3p overexpression could regulate MDM2/p53 signaling pathway to reverse the PTX resistance of NSCLC and induce apoptosis in vitro and vivo.

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Cisplatin- and Paclitaxel-Resistant Ovarian Cancer Cell Lines

“…We did not find any data concerning miR-222-3p expression in PAC-resistance cancer or cancer cell lines. On the contrary to our results, strong downregulation of miR-221-3p was observed in non-small-cell lung cancer (NSCLC) PAC-resistant cell line (A549/Taxol) compared to parental control [ 55 ]. Those differences may be due to other PAC-resistance mechanisms in investigated cell lines.…”

MiRNAs as Anti-Angiogenic Adjuvant Therapy in Cancer: Synopsis and Potential

“…miR-221/222 have also been associated with increased chemoresistance to cisplatin in ovarian ( 103 ) and breast cancer cells ( 104 ). Similar results have been reported with Adriamycin (doxorubicin) ( 105 , 106 ), 5-fluorouracil ( 107 ), and paclitaxel ( 108 ). Representatively, in vivo analysis of downregulation of miR-221/222 through local injection in a breast cancer mouse model enhanced the cisplatin’s tumor growth inhibition capacity, but no analysis on tumor vasculature took place ( 104 ).…”

Current treatments for non-small cell lung cancer

“…At the same time, the downstream target E2F transcription factor 2 (E2F2) that could promote the invasion of NSCLC is downregulated ( 58 ). The overexpression of miR-221–3p could decrease the resistance of paclitaxel by inducing apoptosis accompanied by the inhibition of MDM2/p53 signaling pathway ( 59 ). miR-340 is at a lower expression of NSCLC tissues, and its overexpression could inhibit the migration and invasion of NSCLC cells through targeting RAB27B.…”