Lytic induction therapy for Epstein-Barr virus-positive B-cell lymphomas

Area of Science:

• Oncology
• Virology
• Pharmacology

Background:

• Epstein-Barr virus (EBV)-positive tumors pose a therapeutic challenge due to the virus's latent nature.
• A novel strategy involves inducing EBV's lytic cycle to activate ganciclovir (GCV) for targeted cell killing.
• Identifying drugs that reliably induce EBV lytic infection in B-cell lymphomas is crucial for clinical application.

Purpose of the Study:

• To identify chemotherapeutic agents capable of inducing EBV lytic infection in B-cell lymphomas.
• To evaluate the synergistic efficacy of these agents combined with ganciclovir (GCV) against EBV-driven lymphoproliferative disease.

Main Methods:

• Screening of various chemotherapeutic agents (gemcitabine, doxorubicin, 5-azacytidine, cis-platinum, 5-fluorouracil) for their ability to induce EBV lytic infection in vitro and in vivo.
• Analysis of viral immediate-early gene promoter activation (BZLF1, BRLF1) and identification of key regulatory elements.
• Assessment of cell killing and tumor inhibition in SCID mouse models using combinations of gemcitabine or doxorubicin with GCV.

Main Results:

• Gemcitabine and doxorubicin, but not other tested agents, effectively induced EBV lytic infection in EBV-transformed B cells.
• These drugs activated key viral immediate-early gene promoters, dependent on specific promoter motifs.
• The combination of gemcitabine or doxorubicin with GCV significantly enhanced tumor inhibition in vivo compared to chemotherapy alone, dependent on EBV's BZLF1 gene.

Conclusions:

• Gemcitabine and doxorubicin are effective inducers of EBV lytic infection, offering a potential therapeutic avenue.
• Combining these agents with GCV demonstrates enhanced efficacy against EBV-driven lymphoproliferative disease.
• This strategy holds promise for improving treatment outcomes in patients with EBV-associated malignancies.