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Globally, there are over half a million new patients with head and neck squamous cell carcinomas (HNSCC) every year. The current therapeutic approaches to HNSCC are surgery and adjuvant radiotherapy. These approaches carry a high incidence of metastasis or recurrence from HNSCC cells' radioresistance. Recent studies have revealed that a combination with radiosensitizers can be used to improve the radioresistance in HNSCC; however, few agents are approved as radiosensitizers. The constitutive activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is a vitally oncogenic type of signaling that promotes tumorigenesis, metastasis, and radiotherapy resistance in HNSCC. Pharmacological targeting of PI3K/AKT/mTOR signaling pathway is considered a promising strategy of radiosensitization in HNSCC. In this review, we summarize the oncogenic significance of PI3K/AKT/mTOR signaling in HNSCC with radiotherapy resistance and highlight the therapeutic potential of small molecule inhibitors against PI3K/AKT/mTOR signaling for the radiosensitization in HNSCC treatment. It provides a mechanistic framework for the development of new drugs for radiosensitization in HNSCC radiotherapy via targeting PI3K/AKT/mTOR signaling pathway. [ABSTRACT FROM AUTHOR]

Approximately 500,000 new cases of head and neck squamous cell carcinoma (HNSCC) are reported annually. Radiation therapy is an important treatment for oral squamous cell carcinoma (OSCC). The survival rate of patients with HNSCC remained low (50%) in decades because of radiation therapy failure caused by the radioresistance of HNSCC cells. This study aimed to identify PI3K inhibitors that can enhance radiosensitivity. Results showed that pan-Phosphoinositide 3-kinases (PI3K) inhibitor BKM120 and class I α-specific PI3K inhibitor BYL719 dose-dependently reduced the growth of OSCC cells but not that of radioresistant OML1-R cells. The combination treatment of BKM120 or BYL719 with radiation showed an enhanced inhibitory effect on OSCC cells and radioresistant OML1-R cells. Furthermore, the enhanced inhibitory effect of the combination treatment was confirmed in patient-derived OSCC cells. The triple combination treatment of mTOR inhibitor AZD2014 and BKM120 or AZD2014 and BYL719 with radiation showed a significantly enhanced inhibitory effect on radioresistant OML1-R cells. These results suggest that the PI3K inhibitors are potential therapeutic agents with radiosensitivity for patients with OSCC. [ABSTRACT FROM AUTHOR]

There is high risk of metastasis and recurrence in head and neck squamous cell carcinoma (HNSCC) patients, especially for patient who received definitive surgery and adjuvant radiotherapy. Aberrant activation of PI3K/AKT/mTOR signaling occurs in approximately 80% of HNSCC, which has been indicated to serve as prognostic biomarkers for patients suffer from recurrence or metastasis. Therefore, in this study, we focus on the relationship between the expression level of signaling factors in PI3K/AKT/mTOR pathway and recurrence tumor from HNSCC patients. A tissue microarray (TMA) was constructed from 54 cases of HNSCC patients who received definitive surgery and adjuvant radiotherapy, are followed more than 5 years, and with no previous malignancy and synchronous tumor. Slides were scored and dichotomized by two pathologists and scores. Based on the TMA block with IHC staining, the results showed that PI3K/AKT/mTOR signaling was highly activated both in recurrence and non-recurrence patients. Particularly, in the recurrence population, the results showed the low expression phospho-eukaryotic initiation factor 4E (p-eIF4E) or high expression eIF4E, phospho-eIF4E binding protein 1 (p-4EBP1), phospho-ribosomal protein S6 kinase beta-1 (p-S6K1) and phospho-40S ribosomal protein S6 (p-S6R) exhibited worse overall survival. The expression level of eIF4E and p-4EBP1 were significantly associated with tumor recurrence and recurrence-free survival. Furthermore, high expression level of eIF4E and p-4EBP1 had worse recurrence-free survival. In conclusion, the expression of eIF4E and p-4EBP1 should be considered as predictive biomarkers for the HNSCC patients. This may contribute to potential predictive biomarkers for HNSCC patient who receive adjuvant radiotherapy. [ABSTRACT FROM AUTHOR]

Background: Activation of Ras oncogene in human tumors is associated with radiation-associated metastatic potential. Although ionizing radiation is one important method of cancer treatments, it has been shown to enhance matrix metalloproteinases (MMPs) activity and facilitates a more aggressive cancer phenotype. Our previous studies showed that andrographolide with lower dose rates of radiation could inhibit RAS-transformed cancer metastasis in vivo; however, the molecular mechanisms are not yet clear. In this study, we aimed to explore the anti-metastatic effect of andrographolide combined with radiation on Ras-transformed cells. Methods: RAS-transformed cells were treated with andrographolide in the presence or absence of irradiation (2–4 Gy) or angiotensin II to examine cell invasion. In vivo tumorigenesis assays were also performed. The MMP-2 activity was detected by using Gelatin zymography. Signal transduction of NF-κB subunit, p65 and phosphor-ERK 1/2, were examined by using Western blotting analysis. Results: Treatment with andrographolide inhibited migration of Ras-transformed cells. Andrographolide treatment with radiation significantly inhibited cancer metastasis in vivo. We found that andrographolide exhibited anti-migration and anti-invasive ability against cancer metastasis via inhibition of MMP2 activity rather than affected MMP-9 and EMT. In addition, combined andrographolide with radiation appeared to be more effective in reducing MMP-2 expression, and this effect was accompanied by suppression of ERK activation that inhibits cancer cell migration and invasion. Conclusions: These findings suggest that andrographolide enhances the anti-metastatic effect of radiation in Ras-transformed cells via suppression of ERK–mediated MMP-2 activity. [ABSTRACT FROM AUTHOR]

Objective: Several comorbid measures have been developed and demonstrated the predictive ability for cancer mortality. We conducted a retrospective study on oral squamous cell carcinoma (OSCC) patients to compare the Charlson comorbidity index score (CCIS) to the Elixhauser comorbidity index score (ECIS).Methods: Newly diagnosed OSCC patients (n=232) post major surgery with or without adjuvant therapy were identified from the cancer registry database between 2006 and 2011. Comorbidities present prior to the cancer diagnosis were obtained and adapted to the CCIS and ECIS. The prevalence of comorbid conditions and the influence on disease-specific survival (DSS) rate were calculated and analyzed by Cox regression model. The discriminatory ability of these two comorbid measures was evaluated by using the adjusted hazard ratio and Akaike information criterion (AIC) in a multivariate regression model. The prediction accuracy was assessed using Harrell's c-statistic.Results: Most of the patients (93.5%) were male with a mean age of 54 ± 11 years and 77 of them (33.1%) had at least one comorbid condition. The ECIS was associated DSS, with an additional 10% increased risk observed for mortality for each increased score (HR, 1.10; 95% confidence interval [CI], 1.03-1.18) after adjusting with pathological risk features. However, the CCIS was not an independent prognostic factor for these patients. The ECIS increased discriminatory ability but the CCIS did not improve discrimination.Conclusions: Comorbid conditions significantly influenced the clinical outcomes of patient with OSCC post major surgery. A higher ECIS was associated with worse disease specific survival indicative of a valuable prognostic indicator. The ECIS may be considered in further clinical trials for a variety of cancers, including head and neck cancers. [ABSTRACT FROM AUTHOR]