Early clinical and metabolic response to tazemetostat in advanced relapsed INI1 negative epithelioid sarcoma

Overcoming the therapeutic limitations of EZH2 inhibitors in Burkitt's lymphoma: a comprehensive study on the combined effects of MS1943 and Ibrutinib

Enhancer of zeste homolog 2 (EZH2) and Bruton's tyrosine kinase (BTK) are both key factors involved in the development and progression of hematological malignancies. Clinical studies have demonstrated the potential of various EZH2 inhibitors, which target the methyltransferase activity of EZH2, for the treatment of lymphomas. However, despite their ability to effectively reduce the H3K27me3 levels, these inhibitors have shown limited efficacy in blocking the proliferation of lymphoma cells. To overcome this challenge, we employed a hydrophobic tagging approach utilizing MS1943, a selective EZH2 degrader. In this study, we investigated the inhibitory effects of two drugs, the FDA-approved EZH2 inhibitor Tazemetostat, currently undergoing clinical trials, and the novel drug MS1943, on Burkitt's lymphoma. Furthermore, we assessed the potential synergistic effect of combining these drugs with the BTK inhibitor Ibrutinib. In this study, we evaluated the effects of combination therapy with MS1943 and Ibrutinib on the proliferation of three Burkitt's lymphoma cell lines, namely RPMI1788, Ramos, and Daudi cells. Our results demonstrated that the combination of MS1943 and Ibrutinib significantly suppressed cell proliferation to a greater extent compared to the combination of Tazemetostat and Ibrutinib. Additionally, we investigated the underlying mechanisms of action and found that the combination therapy of MS1943 and Ibrutinib led to the upregulation of miR29B-mediated p53-upregulated modulator of apoptosis PUMA, BAX, cleaved PARP, and cleaved caspase-3 in Burkitt's lymphoma cells. These findings highlight the potential of this innovative therapeutic strategy as an alternative to traditional EZH2 inhibitors, offering promising prospects for improving treatment outcomes in Burkitt's lymphoma.

Preclinical and clinical aspects of using Tazemetostate in human cancers

Abstract:

Epigenetic drugs are novel drug categories with promising effects in different cancers. Tazemetostate is among the drugs that were recently used in clinical settings, especially in the treatment of specific tumors and lymphomas. There are a growing number of ongoing clinical trials evaluating the safety and efficacy of tazemetostate in different cancers. The present review addressed the available preclinical studies evaluating the combination of tazemetostate and other chemotherapy agents in treating different cancers and summarized the limited clinical evidence available regarding the efficacy of this novel Enhancer of Zeste Homolog 2 (EZH2) inhibitor in cancer. Based on the available clinical studies, tazemetostate could be considered a safe epigenetic agent with limited adverse events for treating specific types of lymphomas and solid tumors. However, the superiority of using tazemetostate over other chemotherapy agents in patients with cancer as well as using the drug for other clinical conditions including non-alcoholic steatohepatitis needs further investigation. Moreover, the effect of tazemetostate on human germline cells is clearly evaluated as some animal studies demonstrated that the drug can affect germline epigenome suggesting further studies on this issue.