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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Apoptosis, Colonic Neoplasms, Glucuronosyltransferase, Hyaluronan Synthases, Immunoenzyme Techniques, Mice, Mice, Inbred BALB C, Mice, Nude, RNA, Small Interfering, Reverse Transcriptase Polymerase Chain Reaction, Transfection, Tumor Cells, Cultured.
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Does inhibition of hyaluronan synthase-3 decrease subcutaneous colon cancer growth in mice? Context: Hyaluronan and hyaluronan synthases have been implicated in cancer progression. Hyaluronan synthase-3 is up-regulated in metastatic colon cancer cells (SW620), and its expression mediates cellular growth in vitro. We hypothesized that inhibition of hyaluronan synthase-3 would decrease tumor formation and/or alter the pattern of metastasis in mouse models of colon cancer growth. Hyaluronan synthase-3 was inhibited in SW620 cells by transfection with small interfering RNA (silenced cells); a scrambled sequence served as a negative control. To study primary tumor growth, transfected cells were injected into the flanks of BALB/c nude mice. To study metastasis, an orthotopic model was used. Metastases were confirmed histologically. Student t test and Fisher exact probability test were used for statistical analysis. Inhibition of hyaluronan synthase-3 significantly decreased subcutaneous tumor growth; tumor weight was 0.94 +/- 0.17 g in the hyaluronan synthase-3-silenced group vs 1.70 +/- 0.26 g in the control scrambled group (P < .01). In contrast, metastases were similar in both groups: liver metastases were present in 22% of the silenced group vs 11% of the scrambled group; lung metastases were present in 6% of the silenced group vs 0% of the scrambled group (P = not significant).
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Inhibition of hyaluronan synthase-3 expression in SW620 colon cancer cells decreases subcutaneous tumor growth in mice, but has less of an effect on lung and liver metastases. This observation suggests that hyaluronan synthase-3 may enhance primary colon cancer growth. Final Decision: yes