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Published on: February 6, 2015
In vitro modulation of Bcl-2 levels in small cell lung cancer cells: effects on cell viability
A O Santos1, J P Pereira, M C Pedroso de Lima
1University of Coimbra, Portugal.
Abstract:
Small cell lung cancer (SCLC) is an aggressive disease, representing 15% of all cases of lung cancer, has high metastatic potential and low prognosis that urgently demands the development of novel therapeutic approaches. One of the proposed approaches has been the down-regulation of BCL2, with poorly clarified and controversial therapeutic value regarding SCLC. The use of anti-BCL2 small interfering RNA (siRNA) in SCLC has never been reported. The aim of the present study was to select and test the in vitro efficacy of anti-BCL2 siRNA sequences against the protein and mRNA levels of SCLC cells, and their effects on cytotoxicity and chemosensitization. Two anti-BCL2 siRNAs and the anti-BCL2 G3139 oligodeoxynucleotide (ODN) were evaluated in SCLC cells by the simultaneous determination of Bcl-2 and viability using a flow cytometry method recently developed by us in addition to Western blot, real-time reverse-transcription PCR, and cell growth after single and combined treatment with cisplatin. In contrast to previous reports about the use of ODN, a heterogeneous and up to 80% sequence-specific Bcl-2 protein knockdown was observed in the SW2, H2171 and H69 SCLC cell lines, although without significant sequence-specific reduction of cell viability, cell growth, or sensitization to cisplatin. Our results question previous data generated with antisense ODN and supporting the present concept of the therapeutic interest in BCL2 silencing per se in SCLC, and support the growing notion of the necessity of a multitargeting molecular approach for the treatment of cancer.
Insights
Small cell lung cancer (SCLC) research shows anti-BCL2 small interfering RNA (siRNA) effectively reduced BCL2 protein and mRNA. However, this did not translate to significant improvements in cell viability or cisplatin sensitivity in vitro.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Small cell lung cancer (SCLC) is an aggressive cancer with poor prognosis, necessitating novel therapeutic strategies.
- BCL2 down-regulation is a proposed therapeutic approach for SCLC, but its efficacy remains controversial.
- The use of anti-BCL2 small interfering RNA (siRNA) in SCLC has not been previously investigated.
Purpose of the Study:
- To evaluate the in vitro efficacy of anti-BCL2 siRNA sequences in SCLC cells.
- To assess the impact of anti-BCL2 siRNA on BCL2 protein and mRNA levels, cytotoxicity, and chemosensitization.
- To compare the effects of anti-BCL2 siRNA with an anti-BCL2 oligodeoxynucleotide (ODN).
Main Methods:
- Utilized two anti-BCL2 siRNA sequences and one anti-BCL2 G3139 ODN in SCLC cell lines (SW2, H2171, H69).
- Assessed BCL2 protein and mRNA levels using Western blot and real-time reverse-transcription PCR.
- Determined cell viability, cell growth, and chemosensitization to cisplatin via flow cytometry and cell growth assays.
Main Results:
- Achieved heterogeneous, sequence-specific BCL2 protein knockdown up to 80% with anti-BCL2 siRNAs, contrasting with ODN results.
- Observed no significant sequence-specific reduction in cell viability or cell growth.
- Found no significant sensitization to cisplatin when combined with anti-BCL2 siRNA treatment.
Conclusions:
- Anti-BCL2 siRNA demonstrates effective BCL2 protein and mRNA knockdown in SCLC cells in vitro.
- The observed BCL2 knockdown did not significantly impact SCLC cell viability, growth, or chemosensitivity to cisplatin.
- Results challenge previous findings with antisense ODN and highlight the need for multitargeting approaches in SCLC treatment.
