RESUMEN
PURPOSE: Because of the scarcity of suitable brain cancer drugs, researchers are frantically trying to discover novel and highly potent drugs free of side effects and drug-resistance. Rhenium compounds are known to be nontoxic and exhibit no drug resistance. For that reason, we have developed a series of novel rhenium acetylsalicylato (RAC or ASP) complexes to test their cytotoxicity on brain cancer cells. Also we have attempted to explore the DNAbinding properties of these compounds because many drugs either directly or indirectly bind to DNA. METHODS: We have treated the RAC series compounds on human astrocytoma brain cancer cell lines and rat normal brain astrocyte cells and determined the efficacy of these complexes through in vitro cytotoxicity assay. We carried out the DNA-binding study through UV titrations of a RAC compound with DNA. Also we attempted to determine the planarity of the polypyridyl ligands of the RAC series compounds using DFT calculations. RESULTS: RAC6 is more potent than any other RAC series compounds on HTB-12 human astrocytoma cancer cells as well as on Glioblastoma Multiforme D54 cell lines. In fact, The IC-50 value of RAC6 on HTB-12 cancer cells is approximately 2 µM. As expected, the RAC series compounds were not active on normal cells. The DFT calculations on the RAC series compounds were done and suggest that the polypyridyl ligands in the complexes are planar. The UV-titrations of RAC9 with DNA were carried out. It suggests that RAC9 and possibly all RAC series compounds bind to minor grooves of the DNA. CONCLUSION: Because of the very low activity of RAC6 on normal cells and low lC50 value of on astrocytoma (HTB-12) cell lines, it is possible that RAC6 and its derivatives may potentially find application in the treatment of brain cancers. The DFT calculations and UV titrations suggest that RAC series compounds either bind to DNA intercalatively or minor grooves of the DNA or both. However, it is highly premature to make any definite statement in the absence of other techniques.
RESUMEN
Glioblastoma multiforme (GBM) is the most common and aggressive type of the primary brain tumors with pathologic hallmarks of necrosis and vascular proliferation. The diagnosis of GBM is currently mostly based on histological examination of brain tumor tissues, after radiological characterization and surgical biopsy. The ability to characterize tumors comprehensively at the molecular level raises the possibility that diagnosis can be made based on molecular profiling with or without histological examination, rather than solely on histological phenotype. The development of novel genomic and proteomic techniques will foster in the identification of such diagnostic and prognostic molecular markers. We analyzed the global differential gene expression of a GBM cell line HTB15 in comparison to normal human Astrocytes, and established a few canonical pathways that are important in determining the molecular mechanisms of cancer using global gene expression microarray, coupled with the Ingenuity Pathway Analysis (IPA®). Overall, we revealed a discrete gene expression profile in the experimental model that resembled progression of GBM cancer. The canonical pathway analysis showed the involvement of genes that differentially expressed in such a disease condition that included Inositol pathway, Polo like kinases, nNOS signaling, and Tetrapyrrole biosynthesis. Our findings established that the gene expression pattern of this dreaded brain cancer will probably help the cancer research community by finding out newer therapeutic strategies to combat this dreaded cancer type that leads to the identification of high-risk population in this category, with almost hundred percent mortality rate.
