Chemosensitization of solid tumors by inhibition of Bcl-xL expression using DNAzyme

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• DNAzymes are catalytic DNA molecules with gene-silencing capabilities.
• The bcl-xL gene plays a crucial role in inhibiting apoptosis, making it a target for cancer therapy.

Purpose of the Study:

• To generate and evaluate the therapeutic potential of DNAzymes targeting the bcl-xL gene.
• To investigate the efficacy of bcl-xL DNAzymes in inducing cancer cell apoptosis and enhancing chemosensitivity.

Main Methods:

• Multiplex in vitro selection was used to generate active DNAzymes against bcl-xL.
• Western blot analysis confirmed DNAzyme-mediated down-regulation of bcl-xL expression in cancer cell lines.
• Apoptosis assays, including cytochrome c release and cell survival assays, were performed.
• In vivo studies utilized a xenograft mouse model with ALZET osmotic pumps for DNAzyme delivery.

Main Results:

• The generated DNAzyme effectively down-regulated bcl-xL expression in various cancer cell lines.
• Treatment with the bcl-xL DNAzyme increased cancer cell apoptosis and cytochrome c release.
• Combination therapy with the DNAzyme and Taxol significantly sensitized cancer cells to apoptosis.
• In Taxol-resistant cells, bcl-xL DNAzyme reversed the chemo-resistant phenotype.
• In vivo, the DNAzyme chemosensitized PC3 tumors when combined with Taxol.

Conclusions:

• The bcl-xL DNAzyme effectively induces apoptosis in solid tumors.
• This DNAzyme holds significant potential for combination therapy with chemotherapeutics in cancer treatment.
• Targeting bcl-xL with DNAzymes offers a promising strategy to overcome chemoresistance.