Shingo Mitomo

Downregulation of miR-138 is associated with overexpression of human telomerase reverse transcriptase protein in human anaplastic thyroid carcinoma cell lines

Alterations of several microRNA (miRNA) have been linked to cancer development and its biology. To search for unique miRNA that might play a role in the development of anaplastic thyroid carcinoma (ATC), we examined the expression of multiple miRNA and their functional effects on target genes in human thyroid carcinoma cell lines. We quantitatively evaluated the expression of multiple miRNA in 10 ATC and five papillary thyroid carcinoma (PTC) cell lines, as well as primary tumors from 11 thyroid carcinoma patients (three ATC and eight PTC), using the stem‐loop‐mediated reverse transcription real‐time polymerase chain reaction method. We also examined the target gene specificity of unique miRNA that showed differences in expression between ATC and PTC cell lines. One miRNA, miR‐138, was significantly downregulated in ATC cell lines in comparison with PTC (P < 0.01). Eleven miRNA (including miR‐138) potentially targeting the human telomerase reverse transcriptase (hTERT) gene were totally downregulated in both ATC and PTC cell lines in comparison with normal thyroid tissues. A tendency for an inverse correlation between miR‐138 and hTERT protein expression was observed in the thyroid cancer cell lines, although this failed to reach significance (r = –0.392, P = 0.148). We demonstrated that overexpression of miR‐138 induced a reduction in hTERT protein expression, and confirmed target specificity between miR‐138 and the hTERT 3′‐untranslated region by luciferase reporter assay. These results suggest that loss of miR‐138 expression may partially contribute to the gain of hTERT protein expression in ATC, and that further multiple miRNA targeting hTERT mRNA might be involved in the development of thyroid carcinoma. (Cancer Sci 2008; 99: 280–286)

Sunitinib treatment enabling resection of massive liver metastasis: a case report

IntroductionSunitinib was developed as a molecular-targeted drug to treat advanced renal cell carcinoma. It is not yet known whether liver damage occurs in patients with liver metastases of renal cell carcinoma after sunitinib administration. Here, we report the case of a patient with an inoperable massive liver metastasis of renal cell carcinoma for whom sunitinib administration was dramatically effective with no obvious evidence of liver damage. As a result, the liver metastasis could be resected. We emphasize the dramatic reduction in liver metastasis with sunitinib treatment, and the histopathological effects of sunitinib on the non-tumorous liver parenchyma.Case presentationA 54-year-old Japanese woman was diagnosed with right renal cell carcinoma and underwent right nephrectomy 12 years earlier. She presented to a local clinic with right abdominal pain. A computed tomography scan showed a massive liver metastasis occupying her right hepatic lobe, and she was referred to our hospital for treatment. The diagnosis was not only liver metastasis, but also left renal metastasis. Oral administration of tyrosine kinase inhibitor sunitinib was started. Adverse events due to sunitinib included liver dysfunction, thrombocytopenia, and decreased hemoglobin, but she completed eight courses with the help of drug holidays and dose adjustments. Post-treatment computed tomography showed a dramatic reduction in size of her liver metastasis, enabling right lobectomy of her liver. Histopathological findings showed no obvious liver damage due to chemotherapy in non-cancerous parenchymal areas.ConclusionsWith the availability of sunitinib, some patients with potentially unresectable massive liver metastases of renal cell carcinoma may be able to undergo major hepatectomy curatively and safely with little histopathological damage to non-tumorous liver parenchyma, thus improving their prognosis.