Sirolimus-induced signaling modifications in Kaposi's sarcoma with resolution in a liver transplant recipient.
Sirolimus is one treatment option in transplant recipients with Kaposi's sarcoma (KS), which involves dysregulation of Akt-mammalian target of rapamycin (mTOR) signaling pathway. Signal modifications after sirolimus therapy in organ recipients with KS are largely unknown and not verified. We reported a case of KS found two yr after liver transplantation in which the immunosuppression was changed from tacrolimus, MMF, and steroid to sirolimus alone. In skin, which was found to have persistent KS after a two-month treatment of sirolimus and was removed completely one yr later, KS was no longer present. The patient went well without graft rejection. Tumor biopsies were performed before, two months, and one yr after the start of sirolimus. Immunohistochemical staining of vascular endothelial growth factor (VEGF), p-Akt, p-mTOR, p-p70 S6 kinase, and Western blot for p-tuberin/ tuberous sclerosis complex (TSC)2 was performed. VEGF was suppressed thoroughly in two-month use of sirolimus. In addition, p-Akt and p-mTOR, which were decreased at two months, could not be detected after one yr of treatment. Moreover, p-p70 S6 kinase, expressed strongly in overlying epidermis initially, was suppressed completely after two months of treatment. However, p-tuberin/TSC2, contrary to suggested theoretically, was not detected through all specimens, implying not to be a significant event. Suppressed expression of VEGF, p-Akt, and p-mTOR was the major event of signaling modification through the long-term use of sirolimus.
Ho
Cheng-Maw
CM
Department of Surgery, National Taiwan UniversityHospital, Taipei.
Huang
Shiu-Feng
SF
Hu
Rey-Heng
RH
Ho
Ming-Chih
MC
Wu
Yao-Ming
YM
Lee
Po-Huang
PH
D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008107:Liver Diseases / Q000209:etiology / Q000378:metabolism / Q000601:surgery; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D012514:Sarcoma, Kaposi / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D015398:Signal Transduction / Q000187:drug effects*; D020123:Sirolimus / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy
D007166:Immunosuppressive Agents; D047908:Intracellular Signaling Peptides and Proteins; D020123:Sirolimus