Combining immunotherapy with drug therapy could be a beneficial strategy for treating cancer. Blocking the tumor-producing protein MDM2, by MDM2-inhibiting drug AMG-232, could bolster immunotherapy. While immunotherapy, a form of treatment that uses the body's immune system to recognize, attack and kill tumor cells, has given hope to people across the worldwide, it fails in a significant proportion of cancer patients.
‘With MDM2 amplification and over-expression implicated in various cancers, AMG-232 or similar drugs, could be widely used, and could benefit immunotherapy patients whose tumors have normal MDM2 levels.’
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However, a new study published in the Nature journal Cell Death Discovery suggests that blocking the tumor-promoting protein MDM2 could bolster immunotherapy's effectiveness."Immunotherapy has been one of the biggest breakthroughs in biomedical science and medicine of the last two decades," said Dr. Wafik El-Deiry, professor of pathology and laboratory medicine and associate dean for oncologic sciences at Brown University. "But, it has limitations."
Some people's tumors respond to immunotherapy initially and then relapse. Other patients experience pseudoprogression, where tumors appear to grow before eventually shrinking. And a third group -- between 5% and 29% of patients -- experience hyper-progression, which means that immunotherapy actually worsens their tumor growth.
El-Deiry hopes that blocking MDM2, either through gene-silencing or the MDM2-inhibiting drug AMG-232, could be especially helpful for people with hyper-progression.
Various studies have found that when the MDM2 gene is amplified -- meaning that cells contain too many copies of the gene -- or when the MDM2 protein is overexpressed because the gene is not being regulated properly, tumor cells tend to grow more quickly and are more resistant to immunotherapy.
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In their study, El-Deiry and his colleagues treated cell lines of MDM2-overexpressing ovarian cancer cells with the therapeutic AMG-232. The data show that AMG-232 allowed immune cells to kill the tumor cells much more efficiently and reduced levels of IL-6. These results suggest that MDM2 inhibitors could be combined with immunotherapy to enhance its effectiveness.
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For this specific finding, El-Deiry hopes the study will lead to a clinical trial so the research team can further evaluate the safety and effectiveness of this novel treatment. With MDM2 amplification and over-expression implicated in a variety of cancers, he believes that AMG-232 (or similar drugs, including those that block both MDM2 and a related protein, MDMX) could be widely applicable -- and it could even benefit immunotherapy patients whose tumors have normal MDM2 levels.
"We think this might be a good approach to treat patients whose tumors are predicted to undergo hyper-progression, but I would say our results show that targeting MDM2 in combination with immunotherapy works well even if MDM2 is not amplified or over-expressed," El-Deiry said. "It's tapping into a vulnerability within tumors to help immunotherapy work better."
In addition to El-Deiry, other Brown University authors on the study were Ilyas Sahin, Shengliang Zhang, Arunasalam Navaraj, Lanlan Zhou, Don Dizon and Howard Safran. The study was supported by the Mencoff Family endowed professorship at Brown.
Source-Eurekalert