Enhanced growth suppression of Philadephia1 leukemia cells by targeting bcr3/abl2 and VEGF through antisense strategy

Area of Science:

• Oncology
• Molecular Biology
• Gene Therapy

Background:

• Philadelphia chromosome-positive (Ph+) leukemias, including chronic myeloid leukemia (CML), are driven by the bcr-abl fusion gene.
• Vascular Endothelial Growth Factor (VEGF) plays a crucial role in tumor angiogenesis and progression.
• Targeting both the oncogenic driver and tumor vasculature presents a potential therapeutic strategy.

Purpose of the Study:

• To investigate the efficacy of a combined antisense strategy targeting both bcr-abl and VEGF in suppressing Philadelphia chromosome-positive leukemia.
• To evaluate the additive or synergistic effects of dual antisense oligodeoxyribonucleotides (AS-ODNs) in vitro and in vivo.

Main Methods:

• Design and application of antisense oligodeoxyribonucleotides (AS-ODNs) specifically targeting bcr-abl and VEGF transcripts.
• In vitro studies using K562 cells (a human CML cell line) to assess proliferation inhibition, apoptosis induction, and chemosensitivity.
• In vivo studies using a mouse xenograft model with K562 cells to evaluate tumor growth, microvessel density, and apoptosis.

Main Results:

• Individual AS-ODNs targeting bcr-abl or VEGF demonstrated inhibitory effects on K562 cell proliferation.
• Combined bcr-abl and VEGF AS-ODNs exhibited an additive inhibitory effect on K562 cell growth.
• Combination therapy significantly enhanced K562 cell sensitivity to apoptosis-inducing agents, including STI571 (imatinib).
• In vivo, dual AS-ODN treatment led to significant reductions in leukemia tumor size and microvessel density.
• Increased apoptosis within tumors was observed in mice treated with the combination therapy compared to individual agents.

Conclusions:

• Targeting both bcr-abl and VEGF simultaneously via an antisense strategy results in additive tumor-suppressive actions.
• This dual-targeting approach holds promise for augmenting the efficacy of chemotherapy in chronic myeloid leukemia (CML).
• Combined antisense therapy represents a potential novel strategy for CML treatment by hitting both the oncogenic driver and tumor angiogenesis.