TELOMERASE ASSOCIATED FACTORS AND THEIR ROLES IN CANCER PROGRESSION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cancer cells commonly upregulate the ribonucleoprotein telomerase. Inhibition of telomerase has previously been predicted to slow cancer growth, but only after a sufficient period elapses for telomere shortening to occur. Recently, we have inhibited cancer cell growth specifically by inhibiting telomerase function through an siRNA targeting the template region of wild-type telomerase RNA. Expression of such siRNA in cancer cells resulted in dramatic reduction of telomerase activity, rapid inhibition of cell growth and induction of apoptosis. Unexpectedly, those potent cellular effects were not apparently induced by the disruption of telomere structures, suggesting that inhibition of telomerase by siRNA may inhibit a function of telomerase in cancer cells other than telomere length maintenance. DNA microarray analysis in these cells indicates rapid changes in growth-related gene expression that is independent of interferon response triggered by double stranded RNA. These data suggested that telomerase may be essential for cancer cell proliferation in addition to telomere length maintenance. Therefore, a main focus of our research is to further understand the underlying mechanisms by which telomerase regulates cell proliferation through identification of novel telomerase associated factors. Biochemistal purification of telomerase complexes from the human cancer cell line Hela S3 was achieved using Tandem affinity purification (TAP) protocol. Proteins associated specifically with telomerase were isolated for identification by Mass Spectrometry.