title: Decreased lymphangiogenesis and lymph node metastasis by mTOR inhibition in head and neck cancer.
abstract: Despite our improved understanding of cancer, the 5-year survival rate for head and neck squamous cell carcinomas (HNSCC) patients remains relatively unchanged at 50% for the past three decades. HNSCCs often metastasize to locoregional lymph nodes, and lymph node involvement represents one of the most important prognostic factors of poor clinical outcome. Among the multiple dysregulated molecular mechanism in HNSCCs, emerging basic, preclinical, and clinical findings support the importance of the mTOR signaling route in HNSCC progression. Indeed, we observed here that the activation of mTOR is a widespread event in clinical specimens of HNSCCs invading locoregional lymph nodes. We developed an orthotopic model of HNSCC consisting of the implantation of HNSCC cells into the tongues of immunocompromised mice. These orthotopic tumors spontaneously metastasize to the cervical lymph nodes, where the presence of HNSCC cells can be revealed by histologic and immunohistochemical evaluation. Both primary and metastatic experimental HNSCC lesions exhibited elevated mTOR activity. The ability to monitor and quantitate lymph node invasion in this model system enabled us to explore whether the blockade of mTOR could impact HNSCC metastasis. We found that inhibition of mTOR with rapamycin and the rapalog RAD001 diminished lymphangiogenesis in the primary tumors and prevented the dissemination of HNSCC cancer cells to the cervical lymph nodes, thereby prolonging animal survival. These findings may provide a rationale for the future clinical evaluation of mTOR inhibitors, including rapamycin and its analogues, as part of a molecular-targeted metastasis preventive strategy for the treatment of patients with HNSCC.
authors: Oral and Pharyngeal Cancer Branch, National Institute of Dental Research, NIH, Bethesda, Maryland 20892, USA.
authors: Vyomesh
authors: V
authors: Patel
authors: Christina A
authors: CA
authors: Marsh
authors: Robert T
authors: RT
authors: Dorsam
authors: Constantinos M
authors: CM
authors: Mikelis
authors: Andrius
authors: A
authors: Masedunskas
authors: Panomwat
authors: P
authors: Amornphimoltham
authors: Cherie-Ann O
authors: CA
authors: Nathan
authors: Cherie Ann
authors: CA
authors: Nathan
authors: Bhuvanesh
authors: B
authors: Singh
authors: Roberto
authors: R
authors: Weigert
authors: Alfredo A
authors: AA
authors: Molinolo
authors: J Silvio
authors: JS
authors: Gutkind
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology; D000068338:Everolimus; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D042583:Lymphangiogenesis / Q000187:drug effects*; D008207:Lymphatic Metastasis; D051379:Mice; D016513:Mice, SCID; D020123:Sirolimus / Q000031:analogs & derivatives / Q000627:therapeutic use; D000077195:Squamous Cell Carcinoma of Head and Neck; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology
chemical_list: C493245:CRTC2 protein, human; D014157:Transcription Factors; D000068338:Everolimus; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus