Biomedical subjects
Peter T Rowley
Publications and source records attributed to Peter T Rowley.
Inhibition of telomerase activity in human cancer cells by RNA interference.
Telomerase is an attractive molecular target toward which to direct cancer therapeutic agents because telomerase activity is present in most malignant cells but undetectable in most normal somatic cells. Short duplex RNA (short-interfering RNA or siRNA) has recently been shown to be an effective method for inhibiting the expression of a given gene in human cells. Accordingly, we evaluated the ability of siRNA to inhibit telomerase activity in human cancer cells. Human cancer cell lines were transfected with 21 nt double-stranded RNA homologous to either the catalytic subunit of telomerase (human telomerase reverse transcriptase) or to its template RNA [human telomerase RNA(hTR)]. Both types of agents reduced telomerase activity in a variety of human cancer cell lines representing both carcinomas and sarcomas. Inhibition was dose-dependent, although modest in degree and, as expected, transient in duration. Transfection of HeLa cells using a plasmid containing the hTR gene in both forward and reverse orientations, intended to create a duplex of the hTR transcripts endogenously, resulted in decreased telomerase activity, decreased telomerase RNA content, and decreased telomeric DNA content but no decrease in the untargeted human telomerase reverse transcriptase mRNA. Telomerase inhibition by siRNA is notable because telomerase is regarded as restricted to the nucleus, whereas RNA interference is commonly regarded as restricted to the cytoplasm.
Patient vs. physician as the target of educational outreach about screening for an inherited susceptibility to colorectal cancer.
Are patients identified from a cancer registry better educated directly or via their physician about screening for an inherited susceptibility for colorectal cancer? Of 974 patients diagnosed with colorectal cancer at < or = 60 years from 1987 to 1999 in a five-county area including Rochester, the physicians of 651 patients (67%) forwarded a cancer family history survey to their patient; 459 (71%) completed the survey. Of these 459, 167 (36%) reported having at least one first- or second-degree relative with colon cancer and were sent a set of questionnaires and a more detailed family cancer history form. Of the 167, a total of 101 (60%) continued to qualify by returning the questionnaires. These 101 qualifying patients were randomized to either the patient-education or physician-education group. Of the 101, a total of 47 (47%) came for a free genetic evaluation. Individuals were more likely to accept evaluation if they were parents (p = 0.001), had more cancers of all kinds in their families (p = 0.02), and had a larger social network (p = 0.04). Of the 47 counseled, 36 (77%) chose to have DNA testing at no cost. Of these 47, individuals were more likely to choose DNA testing if they had more cancers in the family (p = 0.04) and fewer symptoms of depression (p = 0.05). Of the 36 tested patients, 6 (20%) were found to have mutations. In summary, acceptance of genetic services was related to the magnitude of the threat (more cancers in the family), perceived ability to deal with the threat (perceived good health and a supportive network), and a desire to inform relatives (being a parent). The two approaches to educating patients, viz. direct patient education vs. education via their physician, did not significantly differ in terms of percentages of patients receiving counseling (42% vs. 51%, respectively) or the percentage choosing DNA testing (32% vs. 37%, respectively).