A Study of The Effects of Novel Rhenium Compounds on Pancreatic and Prostate Cancer Cell Lines

Cancer is the uncontrolled proliferation of abnormal cells. Different treatment options are available to treat the cancers and chemotherapy is one of them. Numerous chemotherapeutic agents have been developed. Depending on the type of cancer, the particular type of chemotherapeutic agent is used. Unfortunately almost all of these drugs suffer from severe side effects and drug resistances. Besides, some of the organic drugs such as alkylating agents, nitrogen mustards, nitrosoureas, alkylsulfonates, triazines, and ethylenimines can eventually lead to leukemia. Long term use of breast cancer drug tamoxifen leads to endometrial cancer. Drugs derived from inorganic coordination compounds such as cisplatin, carboplatin, etc. are highly effective to several cancers. Fortunately they don’t cause leukemia later on. However, they too suffer from severe toxicity and drug resistances. Compared to classical coordination metal complexes, organometallics offer opportunities for the design of novel drugs with metal specific modes of action [1]. For example, numerous organometallic tamoxifen derivatives have been found to be active against both estrogen receptor-positive and estrogen receptor-negative breast cancer cells [2]. On the contrary, tamoxifen can be used for estrogen receptor-positive breast cancer only. It is not at all effective on estrogen receptor-negative breast cancers. Additionally, it leads to endometrial cancer for its prolonged uses. Majority of the organometallic tamoxifen derivatives have been found to have much lower IC-50 values than the IC-50 value of tamoxifen. In fact, organometallic diphenols have IC-50 values of 0.7 and 0.6 µM for estrogen receptor-positive MCF-7 and estrogen receptor-negative MDA-MB-231 breast cancer cells, respectively [3]. Many tricarbonyl rhenium (I) compounds have been found to be active against several cancer cell lines [4] and surprisingly they are not active against normal cells. Based on these facts, we embarked on the study of the cytotoxic properties of the rhenium tosylato complex, (CO)3(5,6-dimethyl-1,10-phenanthroline)ReOTs (abbreviated as TOS5) on BxPC-3 pancreatic cancer and pentylcarbonato complex, (CO)3(2,2’-Bipyridyl)ReOC(O)OC5H11 (abbreviated as PC1) on LNCaP and MDA prostate cancer cell lines.