Radiotherapy (RT) is a mainstay in the treatment of head and neck squamous cell carcinoma (HNSCC). For locally advanced HCSCC, concurrent chemoradiotherapy (CCRT) benefits HCSCC patients in terms of better survival and loco-regional control. In this study, we evaluated changes in oral microbiota in patients, who received CCRT for head and neck cancer. Oral rinsed samples were weekly collected before and during CCRT and at 4 weeks following treatment from HNSCC patients, who had received 70 Gy of radiation delivered to the primary sites for over 7 weeks and concurrent chemotherapy. Oral microbiota changes in three patients were analyzed by next-generation sequencing using 16S rRNA 454 pyrosequencing. On an average, 15,000 partial 16S rRNA gene sequences were obtained from each sample. All sequences fell into 11 different bacterial phyla. During early CCRT, the microbial diversity gradually decreased. In a patient, who did not receive any antibiotics during the CCRT, Firmicutes and Proteobacteria were the most abundant phylum. During the early CCRT, proteobacteria gradually decreased while Firmicutes increased. During the late CCRT, firmicutes gradually decreased while Bacteroides and Fusobacteria increased. In all the patients, yellow complex showed a gradual decrease, while orange and red complex showed a gradual increase during the CCRT. At 4 weeks after CCRT, the recovery of oral microbiota diversity was limited. During CCRT, there was a gradual increase in major periodontopathogens in association with the deterioration of the oral hygiene. Henceforth, it is proposed that understanding oral microbiota shift should provide better information for the development of effective oral care programs for patients receiving CCRT for HNSCC.

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed in cancer cells to support their continuous growth and proliferation. 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid(BCH) is a model compound for study of amino acid transporter as a system L selective inhibitor. We have examined the effect and mechanism of BCH on cell growth suppression in FaDu human head and neck squamous cell carcinoma. The BCH inhibited the L-leucine transport in a concentration-dependent manner with a IC 50 value of 43.8±4.3μM. The majority of L-leucine uptake is, therefore, mediated by LAT1 in FaDu cells. The growth of FaDu cells was inhibited by BCH in the time- and concentration- dependent manners. The formation of DNA ladder was not observed with BCH treatment in the cells. Furthermore, the proteolytic processing of caspase-3 and caspase-7 in the cells was not detected by BCH treatment. These results suggest that the BCH inhibits the growth of FaDu human head and neck squamous cell carcinoma through the intracellular depletion of neutral amino acids for cell growth without apoptotic processing

The human ELAV(embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellul ar mHNAs that contain AU- rich elements in their 3’ - untranslated region , To test the significance of HuR in carcinogenesis of head and neck squamous cell carcinomas(HNSCCs), we have investigated HuH expression from 32 benign epithelial lesions , 14 prema lignant epitheli al lesions and 80 HNSCCs, There were two different staining patterns of HuR in HNSCCs : nuclear expression was seen in 78 7% (63 of 80) 01' cases; and an additional cyto plasmic expression was seen in 28, 7%(23 of 80) 01 cases, Nuclear expression of HuR was s ignificantly increased in premalignant lesions and HNSCCs, whereas increased cytoplasπli c expression of HuR was only observed in HNSCCs Cytoplasmic HuR expression was significantly increased in pa tients of HNSCC younger than 60 yea rs , Al though there was no significant correlation between a natomic s ites of HNSCCs and HuR express ion , cyto plasmic HuR expression was highly increased in HNSCCs of larynx, There was no significant co rrela tion between HuR expression and other clinicopathological parameters such as histological type‘ tumor s ize‘ 0 1' n odal s tatus , ln conclusion, this study s uggests that overexpression of HuR in HNSCCs may be part of a regula tory pathway tha t co ntro ls the mHNA stability 0 1' several important targets in carcinogenesis of HNSCCs