School of Stomatology, Dalian Medical University, 9 Western Section, Southern Route, Lvshun, Dalian 116044, China.
Oral Oncol. 2009 Nov;45(11):991-7. doi: 10.1016/j.oraloncology.2009.05.642. Epub 2009 Jul 23.
Multidrug resistance (MDR) is a major barrier for chemotherapy of many cancers. Mdr-1 plays a key role in the development of MDR as extensively verified. However, the role of Raf-1 overexpression in the development of multidrug resistance in human squamous carcinoma (KBv200) cells remains largely unknown. The aim of this study was to investigate the correlation of Raf-1 overexpression with the development of multidrug resistance in KBv200 cells. Furthermore, we explored the reversal effect of Raf-1 siRNA transfection and Raf-1/Mdr-1 siRNAs co-transfection on the multidrug resistance of KBv200 cells and potential mechanism of reversing the multidrug resistance. MTT and flow cytometry assay were used to investigate the reversal effect of single transfection with either Raf-1 or Mdr-1 siRNA and double transfection with Raf-1/Mdr-1 siRNAs to vincristine of KBv200 cells. RT-PCR, immunofluorescence and Western Blot were used to detect mRNA and protein expression of Raf-1 and multidrug-resistant gene Mdr-1. The results of gene detection showed that the expression levels of both Raf-1 and Mdr-1 were greatly decreased upon Raf-1 silencing alone or in combination with Mdr-1 silencing. Raf-1 or Mdr-1 siRNA single transfection could reverse the multidrug resistance of KBv200 cells effectively. Compared with single transfection, Raf-1/Mdr-1 siRNAs co-transfection can significantly reduce IC(50) values and increase the apoptotic rates of KBv200 cells. The above results suggested that Raf-1 gene may be a novel target for reversing the multidrug resistance of human squamous carcinoma cells. Raf-1/Mdr-1 siRNAs co-transfection might be a promising approach to abrogate the multidrug resistance of cancer cells. The potential mechanism may be via inhibiting the multidrug-resistant gene Mdr-1 expression efficiently.
多药耐药（MDR）是许多癌症化疗的主要障碍。Mdr-1 在多药耐药的发展中起着关键作用，这已被广泛证实。然而，Raf-1 过表达在人鳞状细胞癌（KBv200）细胞多药耐药发展中的作用在很大程度上仍然未知。本研究旨在探讨 Raf-1 过表达与 KBv200 细胞多药耐药发展的相关性。此外，我们还探讨了 Raf-1 siRNA 转染和 Raf-1/Mdr-1 siRNAs 共转染对 KBv200 细胞多药耐药的逆转作用及其潜在的逆转多药耐药机制。MTT 和流式细胞术检测 Raf-1 或 Mdr-1 siRNA 单转染以及 Raf-1/Mdr-1 siRNAs 共转染对 KBv200 细胞长春新碱的逆转作用。采用 RT-PCR、免疫荧光和 Western Blot 检测 Raf-1 和多药耐药基因 Mdr-1 的 mRNA 和蛋白表达。基因检测结果表明，Raf-1 沉默单独或与 Mdr-1 沉默联合可显著降低 Raf-1 和 Mdr-1 的表达水平。Raf-1 或 Mdr-1 siRNA 单转染可有效逆转 KBv200 细胞的多药耐药性。与单转染相比，Raf-1/Mdr-1 siRNAs 共转染可显著降低 KBv200 细胞的 IC50 值并增加其凋亡率。上述结果表明，Raf-1 基因可能是逆转人鳞状细胞癌多药耐药的新靶点。Raf-1/Mdr-1 siRNAs 共转染可能是一种有前途的方法，可以消除癌细胞的多药耐药性。潜在的机制可能是通过有效抑制多药耐药基因 Mdr-1 的表达。
