Even as the introduction of combination chemotherapy using pemetrexed and cisplatin(Alimta Therapy) was a watershed event in the history of mesothelioma treatments, research into the disease’s underlying cellular activity has shown that mesothelioma cells demonstrate a natural resistance to most forms of chemotherapy, as well as a natural resistance to apoptosis. This research has postulated that the disease’s anti-apoptotic tendency may be one of the primary reasons for its aggressiveness and its ability to resist long-term management. Therapies using pemetrexed and cisplatin have certainly achieved longer median survival times than previous therapies have achieved, but they are still not a curative solution for pleural mesothelioma or peritoneal mesothelioma. At some point in a patient’s treatment, the chemo agents begin to lose efficacy and the disease eventually overcomes the treatment’s ability to manage it. If this is due to the disease’s natural resistance to apoptosis, then understanding the biological mechanisms responsible for this resistance should offer researchers the chance to develop treatments that account for these mechanisms, which could then lead to the development of more effective therapies than are currently available.

One of the leading genetic candidates for influencing mesothelioma’s apoptotic resistance is p21, a gene that regulates certain aspects of the S phase—the synthesis phase—of the cell cycle. High levels of p21 expression have been implicated in prior research regarding anti-apoptotic behavior and it has been shown to be highly expressed in mesothelioma cell tissues and cell lines.

Researchers in Italy conducted a study where they investigated the relationship between p21 expression and mesothelioma’s resistance or susceptibility to apoptosis and cytotoxic treatment. They found that p21 was expressed within in tumor cells in response to some chemotherapy agents, which may explain why mesothelioma is so resistant to chemotherapy: even as the chemo agents are being absorbed by the cancer cells, the cells are expressing a genetic agent, p21, that increases their resistance to apoptosis, and therefore, the cytotoxic effects of chemotherapy.

The researchers found that if they could disrupt the expression of p21 in these cells then the cytotoxic effects of the chemotherapy agents they were studying were greatly enhanced. Their results were so successful that they are now calling for more research into the effects of p21 expression in mesothelioma and, specifically, the study of novel therapeutic techniques to inhibit its expression among mesothelioma cells.

Labels: chemotherapy, mesothelioma, treatments