title: Expression and clinical significance of the Kv3.4 potassium channel subunit in the development and progression of head and neck squamous cell carcinomas.
abstract: The concept of ion channels as membrane therapeutic targets and diagnostic/prognostic biomarkers has attracted growing attention. We therefore investigated the expression pattern and clinical significance of the Kv3.4 potassium channel subunit during the development and progression of head and neck squamous cell carcinomas (HNSCCs). KCNC4 mRNA levels were determined by real-time RT-PCR in both HNSCC tissue specimens and derived cell lines. Kv3.4 protein expression was evaluated by immunohistochemistry in paraffin-embedded tissue specimens from 84 patients with laryngeal/pharyngeal squamous cell carcinomas and 67 patients with laryngeal dysplasias. Molecular alterations were correlated with clinicopathological parameters and patient outcome. Increased KCNC4 mRNA levels were found in 15 (54%) of 28 tumours, compared to the corresponding normal epithelia and varied mRNA levels were detected in 12 HNSCC-derived cell lines analysed. Increased Kv3.4 protein expression was observed in 34 (40%) of 84 carcinomas and also at early stages of HNSCC tumourigenesis. Thus, 35 (52%) of 67 laryngeal lesions displayed Kv3.4-positive staining in the dysplastic areas, whereas both stromal cells and normal adjacent epithelia exhibited negligible expression. No significant correlations were found between Kv3.4-positive expression in HNSCC and clinical data; however, Kv3.4 expression tended to diminish in advanced-stage tumours. Interestingly, patients carrying Kv3.4-positive dysplasias experienced a significantly higher laryngeal cancer incidence than did those with negative lesions (p = 0.0209). In addition, functional studies using HNSCC cells revealed that inhibition of Kv3.4 expression by siRNA leads to the inhibition of cell proliferation via selective cell cycle arrest at the G2/M phase without affecting apoptosis. Collectively, these data demonstrate for the first time that Kv3.4 expression is frequently increased during HNSCC tumourigenesis and correlated significantly with a higher cancer risk. Our findings support a role for Kv3.4 in malignant transformation and provide original evidence for the potential clinical utility of Kv3.4 expression as a biomarker for cancer risk assessment.
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias and Instituto Universitario de Oncología del Principado de Asturias, Oviedo, Spain.
authors.forename: Sofía Tirados
authors.initials: ST
authors.lastname: Menéndez
authors.forename: Juan P
authors.initials: JP
authors.lastname: Rodrigo
authors.forename: Eva
authors.initials: E
authors.lastname: Allonca
authors.forename: Darío
authors.initials: D
authors.lastname: García-Carracedo
authors.forename: Gustavo
authors.initials: G
authors.lastname: Alvarez-Alija
authors.forename: Sara
authors.initials: S
authors.lastname: Casado-Zapico
authors.forename: Manuel F
authors.initials: MF
authors.lastname: Fresno
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodríguez
authors.forename: Carlos
authors.initials: C
authors.lastname: Suárez
authors.forename: Juana M
authors.initials: JM
authors.lastname: García-Pedrero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D018450:Disease Progression; D004812:Epidemiologic Methods; D005260:Female; D015870:Gene Expression; D006258:Head and Neck Neoplasms / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009367:Neoplasm Staging; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D051670:Shaw Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; C492015:KCNC4 protein, human; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D051670:Shaw Potassium Channels