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Updated: Jul 15, 2026
Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 6, 2015
Bcl-XL small interfering RNA sensitizes cisplatin-resistant human lung adenocarcinoma cells
Xiaoyong Lei1, Zexiang Huang, Miao Zhong
1Institute of Pharmacy and Pharmacology, University of South China, Hengyang 421001, China. lei_xiaoyong@yahoo.com.cn
Abstract:
Bcl-XL is overexpressed in a variety of human tumors and is involved in tumorigenesis and chemoresistance. This study investigated the inhibitory effect of the hairpin Bcl-XL small interfering RNA (siRNA) on the expression of the Bcl-XL gene in the cisplatin (DDP)-resistant human lung adenocarcinoma cell line A549/DDP, and the effect of Bcl-XL siRNA on drug sensitization in A549/DDP cells. Bcl-XL siRNA and negative siRNA plasmids were constructed and stably transfected into A549/DDP cells. Reverse transcription-polymerase chain reaction and Western blot analysis were used to detect the target gene expression. Spontaneous apoptosis of cells was detected by acridine orange and ethidium bromide staining. Drug sensitivity of the cells to DDP was analyzed with dimethylthiazol-diphenyltetrazolium bromide (MTT) and flow cytometry. Expression levels of Bcl-XL mRNA and protein in siRNA stable transfectants were clearly reduced as compared with negative siRNA transfectants and untreated cells. MTT results indicated that Bcl-XL transfectants had a higher cell inhibition rate than the negative vector or untreated cells after treatment with 0.2-200 micarog/ml DDP. Flow cytometry revealed increased apoptosis in Bcl-XL siRNA cells. After the addition of 20 microg/ml DDP, siRNA targeting of the Bcl-XL gene specifically down-regulated gene expression in A549/DDP cells, increased spontaneous apoptosis, and sensitized cells to DDP. The results showed that Bcl-XL siRNA contributed to an increase of DDP-induced cell death in non-small-cell lung cancer and sensitized cells to DDP, leading to increased the effectiveness of the drug in treating non-small-cell lung cancer.
Insights
Small interfering RNA (siRNA) targeting Bcl-XL reduces gene expression in lung cancer cells. This enhances cisplatin chemotherapy effectiveness by increasing apoptosis and drug sensitivity.
Area of Science:
- Molecular Biology
- Oncology
- Gene Therapy
Background:
- Bcl-XL overexpression is common in human tumors, contributing to cancer development and resistance to chemotherapy.
- Cisplatin (DDP) is a key chemotherapy drug, but resistance limits its effectiveness in treating non-small-cell lung cancer (NSCLC).
Purpose of the Study:
- To investigate the inhibitory effect of Bcl-XL small interfering RNA (siRNA) on Bcl-XL gene expression in cisplatin-resistant A549/DDP lung adenocarcinoma cells.
- To evaluate the impact of Bcl-XL siRNA on sensitizing these cells to cisplatin treatment.
Main Methods:
- Stable transfection of A549/DDP cells with Bcl-XL siRNA or negative control siRNA.
- Quantitative assessment of Bcl-XL mRNA and protein expression using RT-PCR and Western blot.
- Analysis of spontaneous and DDP-induced apoptosis via acridine orange/ethidium bromide staining and flow cytometry.
- Evaluation of drug sensitivity using MTT assays and flow cytometry.
Main Results:
- Bcl-XL siRNA significantly reduced Bcl-XL mRNA and protein levels in A549/DDP cells compared to controls.
- Cells transfected with Bcl-XL siRNA exhibited increased sensitivity to DDP, showing higher inhibition rates.
- Bcl-XL siRNA treatment led to increased spontaneous apoptosis and enhanced DDP-induced apoptosis in the lung cancer cells.
Conclusions:
- Targeting Bcl-XL with siRNA effectively down-regulates its expression in cisplatin-resistant lung cancer cells.
- Bcl-XL siRNA enhances the efficacy of DDP by increasing apoptosis and overcoming chemoresistance.
- This approach holds potential for improving DDP treatment outcomes in non-small-cell lung cancer.
