Kronos Bio Data Presentation at EORTC-NCI-AACR Symposium Highlights the Importance of p300 KAT Inhibition in HPV-Driven Tumors

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Kronos Bio, Inc.
Kronos Bio, Inc.

– Preclinical data demonstrate that inhibiting the p300 KAT domain reactivates p53 in HPV-driven tumors resulting in anti-tumor activity –

SAN MATEO, Calif., and CAMBRIDGE, Mass., Oct. 23, 2024 (GLOBE NEWSWIRE) -- Kronos Bio, Inc. (Nasdaq: KRON), a company dedicated to developing small molecule therapeutics that address cancers and autoimmune diseases driven by deregulated transcription, today announced preclinical data from its p300 KAT inhibitor program for human papillomavirus (HPV)-driven tumors at the EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics.

Kronos Bio is exploring the utility of its p300 KAT inhibitor, KB-9558, for HPV-driven tumors. In the presentation, the authors show that the HPV genome preferentially integrates into transcriptionally active regions in the human genome where it becomes dependent on p300 to drive expression of its E6 and E7 oncogenes. It is widely recognized that elevated transcription of HPV E6 and E7 genes promotes degradation of tumor suppressors p53 and Rb. Importantly, inhibition of p300 KAT activity was highly selective in repressing the transcription of E6 and E7, which in turn led to restoration of the p53 and Rb pathways and drove anti-tumor effects through apoptosis and inhibition of uncontrolled tumor cell growth.

"Continued expression of certain viral genes, especially E6 and E7, plays a critical role in tumor growth and progression of HPV-driven tumors, including head & neck, cervical, and other anogenital cancers. Importantly, there are no approved targeted therapies that inhibit E6 and E7,” said Charles Lin, Ph.D., chief scientific officer of Kronos Bio. "While this is early-stage research, given the ability of p300 KAT inhibition to target E6 and E7 and restore tumor suppressor pathways, we believe this p300 KAT inhibitor has the potential to be a remarkable and unique approach toward ensuring that fewer people suffer from HPV-driven cancer."

In the presentation titled, "Oncogenic human papillomavirus hijacks p300 to drive viral transcription, creating a therapeutic vulnerability that can be exploited with selective p300/CBP catalytic inhibitors", the authors describe the experiments that led to the following key findings:

  • HPV integrates into the human genome at specific locations where p300 regulates transcription

  • p300 inhibition demonstrated specific and potent reduction of expression of HPV oncogenes E6 and E7, both at the RNA and protein level

  • Loss of E6 and E7 led to restoration of p53 and Rb tumor suppressor pathways which led to the upregulation of p53 activated genes (e.g., CDKN1A) and downregulation of Rb repressed genes (e.g., CDK1)

  • Re-expression of E6 and E7 from an exogenous lentiviral vector where viral oncogene transcription is not mediated by p300 KAT activity reversed the effects of p300 KAT inhibition on p53 restoration and anti-tumor effects

  • These findings support the potential of KB-9558, a p300 KAT inhibitor, to treat HPV-driven tumors given its potential to suppress E6 and E7 expression and restore the p53 pathway