Local and systemic Curcumin C3 complex inhibits 4NQO-induced oral tumorigenesis via modulating FGF-2/FGFR-2 activation.

Head and Neck Squamous cell carcinoma (HNSCC) can be characterized by synchronous tumors in the upper aerodigestive tract. Second primary tumors as a result of field cancerization are a significant problem amongst patients with risk factors for HNSCC, indicating a need for chemo preventive agents. We investigated the efficacy of local and systemic Curcumin C3 complex (C3); a purified mixture of Curcumin, bisdemethoxy Curcumin and demethoxy Curcumin as a chemo preventative agent in 4-nitroquinoline-1-oxide (4NQO)-induced tumorigenesis in mice. The effect of local C3 application was compared to C3 administered orally and in combination with systemic administration. C57Bl/6 mice were administered 4NQO (50 µg/ml) in the drinking water for 16 weeks. At 12 weeks, mice were subjected to daily treatment with either vehicle (control), or 15 mg C3 complex by local delivery, gavage, or combined local and gavage for 28 days (16 week time point), and followed up to 22 weeks. Compared to local and oral systemic C3 administration, combination of local and systemic application significantly decreased multiplicity of 4NQO-induced preneoplastic and neoplastic lesions (p<0.05). Treatment with C3 correlated with a decrease in cell proliferation compared to the 4NQO group. Further, pre-treatment with C3 complex significantly attenuated 4NQO induced expression of basic fibroblast growth factor (FGF-2) and its cognate receptor FGFR-2, suggesting an important role of FGF-2/FGFR-2 axis in chemoprevention of HNSCC (p<0.05). Our findings suggest that a combination of local and systemic C3 complex could effectively target proliferation and inhibit 4NQO-induced tumorigenesis via modulation of the FGF-2/FGFR-2 axis as a mechanism for its efficacy.

Survival outcomes based on systemic agent used concurrently with radiation in human-papillomavirus associated oropharyngeal cancer.

PURPOSE: To investigate survival outcomes of patients treated with concurrent cetuximab and radiotherapy for primary management of both HPV positive and negative OPSCC, and compare the results to traditional platinum-based therapy. We hypothesize that the use of cetuximab in the HPV positive OPSCC patients will result in inferior survival based on tumor biological differences. STUDY DESIGN: A single institution retrospective analysis of 304 patients. The primary outcomes of interest were 1) overall survival and 2) relapse free survival. Pearson Chi-square tests were used to compare proportions between subgroups. One-way analysis of variance was used to compare the continuous variable age between subgroups. Kaplan-Meier method was used to produce survival curves, and comparisons between survival curves were made using the log-rank test. The survival functions comparing subgroups of chemotherapy were analyzed using semi-parametric (i.e. Cox proportional hazards models) and fully parametric regression with Weibull distributions. Multivariable models were adjusted for age at diagnosis, gender, race, chemotherapy, radiotherapy, and cancer stage. RESULTS: In the multivariable analysis, the hazard ratio for cetuximab compared to cisplatin or carboplatin/paclitaxel was HR=0.77[95% CI = 0.67, 0.90] in the HPV - group, suggesting more favorable outcomes for the patients on cetuximab in this group. However, in the HPV + cohort, the hazard ratio was 1.88 [95% CI = 1.42, 2.50] for those patients treated with cetuximab vs platinum-based therapy. CONCLUSIONS: Our data suggest that cetuximab may have inferior outcomes in HPV-associated OPSCC compared to traditional platinum-based therapy.

Rapamycin targets Interleukin 6 (IL-6) expression and suppresses endothelial cell invasion stimulated by tumor cells.

mTOR inhibitors have potent antiangiogenic and anti-lymphangiogenic effects in addition to their growth inhibitory effects in head and neck squamous cell carcinoma (HNSCC). Lymphatogenous spread is much more predominant in HNSCC than hematogenous spread and significantly decreases survival. In this study we evaluated the effects of rapamycin on targeting tumor-stroma crosstalk in HNSCC. HNSCC tumor cells (FaDu) and human lymphatic endothelial cells (HMEC-1A) were co-cultured in various combinations using transwell cell culture inserts to study tumor-stroma crosstalk and the effects of mTOR inhibitor rapamycin. Levels of growth factors and cytokines in cell culture media were measured using Milliplex bead immunoassay (EMD Millipore) and ELISA assay (R&D Systems). We found that conditioned media collected from tumor cells or co-culture with tumor cells significantly increased the invasiveness of lymphatic and blood vascular endothelial cells (P<0.05), while there was no effect of conditioned media collected from endothelial cell cultures or co-culture with endothelial cells on tumor cell invasiveness. There was a significant effect of rapamycin on both baseline and tumor cell stimulated invasiveness of endothelial cells (P<0.05). Importantly the level of IL-6 secreted in media increased significantly in tumor-endothelial cell co-culture compared to monocultures. Rapamycin significantly suppressed secretion of IL-6 by tumor cells (P<0.05). Thus, HNSCC cells produce chemotactic stimuli that promote endothelial cell invasion toward tumor cells that can stimulate lymphangiogenesis. Rapamycin effectively reverted the stimulatory effect of IL-6 secreted by tumor cells on endothelial cell invasiveness.

Photopreventive Effect and Mechanism of AZD4547 and Curcumin C3 Complex on UVB-Induced Epidermal Hyperplasia.

Aggressive cutaneous squamous cell carcinoma (cSCC) of the skin is the second most common type of skin cancer in the United States due to high exposure to ultraviolet B (UVB) radiation. In our previous studies, Curcumin C3 complex (C3), a standardized preparation of three curcumonoids, delayed UVB-induced tumor incidence and inhibited multiplicity. Exposure to UVB activates mTOR and FGFR signaling that play a key role in skin tumorigenesis. The purpose of this study was to investigate the efficacy of C3 complex to afford protection against acute UVB-induced hyperproliferation by targeting the mTOR and FGFR signaling pathways. Pretreatment with C3 complex significantly inhibited UVB-induced FGF-2 induction, FGF-2-induced cell proliferation, progression and colony formation, mTORC1 and mTORC2 activation, and FGFR2 phosphorylation in the promotion-sensitive JB6 cells epithelial cells. Further, FGFR was critical for UVB-induced mTOR activation, suggesting an important role of FGFR2 in UVB-induced mTOR signaling. SKH-1 mice pretreated with C3 (15 mg/kg/b.w.) for 2 weeks followed by a single exposure to UVB (180 mj/cm(2)) significantly attenuated UVB-induced mTORC1, mTORC2, and FGFR2 activation. To further assess the role of FGFR in UVB-induced hyperproliferation, SKH-1 mice were pretreated with AZD4547 (5 mg/kg/b.w.); a selective pan-FGFR kinase inhibitor followed by single exposure to UVB (180 mj/cm(2)). AZD4547 significantly inhibited UVB-induced mTORC1 and mTORC2 activation, epidermal hyperplasia and hyperproliferation. Our studies underscore the importance of FGFR signaling in UVB-induced acute skin changes and the role of FGFR/mTOR signaling in mediating the effects of C3 complex in the pathogenesis of skin cancer.

EBV and not HPV sensitizes tobacco-associated head and neck cancer cell line FaDu to radiotherapy.

Conclusion EBV radiosensitized the p53 mutant tobacco associated head and neck cell line, FaDu. Objectives In the head and neck, HPV is a major risk factor associated with tonsil and base of tongue cancers, while a majority of undifferentiated nasopharyngeal cancers are positive for EBV. Clinically, head and neck tumors positive for HPV or EBV are more radiosensitive than tumors associated with tobacco and alcohol. This study aimed to evaluate whether viral infections can sensitize tobacco-associated head and neck squamous cell carcinoma cell line that harbors multiple mutations, especially TP53, to radiotherapy. Method Four FaDu cell lines (vector control - FaDu-DN; FaDu expressing HPV16 E6/E7 - FaDu-HPV; FaDu infected with EBV - FaDu-EBV; and FaDu-HPV infected with EBV - FaDu-HE) were evaluated for their radiation sensitivity using clonogenic assay. Cell cycle, protein expression, apoptosis, and cellular senescence were analyzed. Results FaDu-EBV and FaDu-HE exhibited significantly increased radiosensitivity in comparison with the control cell line. Radiation-induced cell cycle arrest was altered in all cell lines expressing viral genes. The observed distribution of cells at G1 and S phases was associated with a significant increase in expression of p21 protein along with decreased levels of pAKT/AKT and pERK/ERK ratio (p < 0.05) and increased cellular senescence (p < 0.05).

Enhanced Systemic Bioavailability of Curcumin Through Transmucosal Administration of a Novel Microgranular Formulation.

BACKGROUND/AIM: Curcumin is a promising nutraceutical for chemoprevention of head and neck squamous cell carcinoma (HNSCC). Capsular formulations of curcumin demonstrate low systemic bioavailability. We aimed to determine if curcumin levels were higher in healthy volunteers and cancer patients with microgranular curcumin that allows for transmucosal absorption and identify a consistent biomarker. PATIENTS AND METHODS: Eight healthy volunteers and 15 HNSCC patients completed the trials. Serum levels of curcumin were measured by HPLC. Biological activity of curcumin was assessed with Multiplex Immunoassay and immunohistochemistry. RESULTS: We achieved higher serum levels of curcumin compared to trials using capsular formulation. In cancer patients a significant decrease in expression of fibroblast growth factor-2 (FGF-2) in post-biopsy samples and decreased serum levels of FGF-2, granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-17 (IL-17) (p<0.05) was observed. CONCLUSION: Transmucosal administration of microgranular curcumin leads to enhanced curcumin bioavailability that is associated with significant biological effects.

Association between human papilloma virus/Epstein-Barr virus coinfection and oral carcinogenesis.

BACKGROUND: The recent epidemic of head and neck squamous cell carcinomas associated with human papilloma virus (HPV) has not addressed its association with lymphoid tissue in the oropharynx or the potential role of Epstein-Barr virus (EBV)/HPV coinfection. METHODS: The prevalence of HPV and EBV infection/coinfection and CD21 mRNA expression were determined in normal and cancerous tissues from the oropharynx using in situ hybridization (ISH), p16, and quantitative reverse transcriptase PCR (qRT-PCR). The effects of coinfection on tumorigenicity were evaluated using proliferation and invasion assays. RESULTS: Normal oropharynx, tonsil, non-cancer base of tongue (BOT), and BOT from sleep apnea patients demonstrated EBV positivity ranging from 7% to 36% depending on the site and methods of detection used (qRT-PCR or ISH). Among non-malignant BOT samples, HPV positivity was noted only in 20%. The percent of tonsil and BOT cancers positive for HPV (up to 63% and 80%, respectively) or coinfected with HPV/EBV (up to 25% and 70%, respectively) were both significantly associated with cancer status. Notably, HPV/EBV coinfection was observed only in malignant tissue originating in lymphoid-rich oropharynx sites (tonsil, BOT). CD21 mRNA (the major EBV attachment receptor) was detected in tonsil and BOT epithelium, but not in soft-palate epithelium. Coinfected cell lines showed a significant increase in invasiveness (P < 0.01). CONCLUSIONS: There is a high prevalence of HPV/EBV infection and coinfection in BOT and tonsil cancers, possibly reflecting their origins in lymphoid-rich tissue. In vitro, cells modeling coinfection have an increased invasive potential.

Serum biomarkers in head and neck squamous cell cancer.

IMPORTANCE: Serum biomarkers may be useful in the evaluation of suspected head and neck squamous cell cancer (HNSCC) and as indicators of treatment success or failure in adjuvant and chemopreventive clinical trials. OBJECTIVE: To determine serum cytokine and chemokine concentrations altered in patients with HNSCC compared with healthy volunteers to identify potential biomarkers. DESIGN, SETTING, AND PARTICIPANTS: A retrospective experimental laboratory study at Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport. Serum samples from 50 patients with stages II, III, and IV HNSCC and 20 healthy volunteers were available for study. Primary tumor sites represented in the patient group included the nasal cavity, oral cavity, oropharynx, hypopharynx, and larynx. INTERVENTIONS: Following institutional review approval and written informed consent, blood samples were drawn from patients. No intervention, to include any kind of diagnostic workup or treatment, was provided to patients during the course of this study. MAIN OUTCOMES AND MEASURES: The main outcome measures were the quantification of cytokine and chemokine concentrations in serum samples. Luminex multiplex panel technology was used for simultaneous measurement of 18 analytes, including fibroblast growth factor 2, granulocyte-macrophage colony-stimulating factor, growth-related oncogene, interferon (IFN)-γ, interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, inducible protein (IP)-10, soluble CD40 ligand, tumor necrosis factor, and vascular endothelial growth factor. RESULTS: The serum samples of patients with HNSCC contained lower levels of IFN-γ (mean patient serum level, 6.08 pg/mL, compared with the mean control level, 26.20 pg/mL; P = .004), IL-13 (mean patient serum level, 2.85 pg/mL, compared with the control mean level, 7.23 pg/mL; P = .02), and macrophage inflammatory protein-1ß (MIP-1ß) (mean patient serum level, 14.91 pg/mL, compared with the mean control level, 28.98 pg/mL; P = .004), and elevated levels of IP-10 (mean patient serum level, 359.24 pg/mL, compared with mean control level, 216.40 pg/mL; P = .04). All other markers tested were not significantly different between patients with cancer and controls. CONCLUSIONS AND RELEVANCE: This pilot study demonstrated a significant decrease in serum IFN-γ, IL-13, and MIP-1ß levels and a significant elevation of serum IP-10 concentration in patients with HNSCC, irrespective of primary tumor site. If validated in larger, independent studies, these serum biomarkers may be useful in the diagnosis and treatment of HNSCC. In the future, a defined, multianalyte screening panel could facilitate early diagnosis of HNSCC, allowing for earlier treatment and thereby reducing patient mortality.

Anti-lymphangiogenic properties of mTOR inhibitors in head and neck squamous cell carcinoma experimental models.

BACKGROUND: Tumor dissemination to cervical lymph nodes via lymphatics represents the first step in the metastasis of head and neck squamous cell carcinoma (HNSCC) and is the most significant predictor of tumor recurrence decreasing survival by 50%. The lymphatic suppressing properties of mTOR inhibitors are not yet well understood. METHODS: Lymphatic inhibiting effects of rapamycin were evaluated in vitro using two lymphatic endothelial cell (LEC) lines. An orthotopic mouse model of HNSCC (OSC-19 cells) was used to evaluate anti-lymphangiogenic effects of rapamycin in vivo. The incidence of cervical lymph node metastases, numbers of tumor-free lymphatic vessels and those invaded by tumor cells in mouse lingual tissue, and expression of pro-lymphangiogenic markers were assessed. RESULTS: Rapamycin significantly decreased lymphatic vascular density (p = 0.027), reduced the fraction of lymphatic vessels invaded by tumor cells in tongue tissue (p = 0.013) and decreased metastasis-positive lymph nodes (p = 0.04). Rapamycin also significantly attenuated the extent of metastatic tumor cell spread within lymph nodes (p < 0.0001). We found that rapamycin significantly reduced LEC proliferation and was correlated with decreased VEGFR-3 expression in both LEC, and in some HNSCC cell lines. CONCLUSIONS: The results of this study demonstrate anti-lymphangiogenic properties of mTOR inhibitors in HNSCC. mTOR inhibitors suppress autocrine and paracrine growth stimulation of tumor and lymphatic endothelial cells by impairing VEGF-C/VEGFR-3 axis and release of soluble VEGFR-2. In a murine HNSCC orthotopic model rapamycin significantly suppressed lymphovascular invasion, decreased cervical lymph node metastasis and delayed the spread of metastatic tumor cells within the lymph nodes.

Dual PI3K/mTOR inhibitors: does p53 modulate response?

Head and neck squamous cell carcinomas have multiple genetic alterations that can influence clinical response to treatment. It is important to evaluate how distinct alterations affect response to targeted agents to identify a subset of patients who can benefit from therapy, improving survival and decreasing toxicity.

Curcumin inhibits UV radiation-induced skin cancer in SKH-1 mice.

OBJECTIVE: As skin cancer incidence increases, research has focused on novel chemopreventive agents that inhibit tumor formation. In prior experimentation, curcumin, a naturally occurring food substance and anticarcinogenic agent, inhibited cutaneous squamous cell carcinoma xenograft growth. We hypothesize curcumin will inhibit UVB radiation-induced skin cancer growth in mice, approximating a human chemopreventive model. STUDY DESIGN: Randomized experimental animal and laboratory study. SETTING: Louisiana State University Health Sciences Center-Shreveport, Louisiana. SUBJECTS AND METHODS: SKH-1 mice were pretreated with oral or topical curcumin or oral or topical control (n = 11/group) for 14 days. Mice received UVB radiation 3 times weekly for 24 weeks or were not radiated. Number of tumors formed and time to tumor onset for each mouse were recorded through tumor harvest after week 24. Tumor multiplicity and time to tumor onset were compared. RESULTS: Time to tumor onset was significantly shorter in control mice compared to mice receiving either oral (P = .025) or topical (P = .015) curcumin. A significant difference in the average number of tumors formed per mouse was seen, as fewer tumors were formed in the oral curcumin (P = .01) and topical curcumin (P = .01) groups, compared with respective controls. No significant difference in average number of tumors per mouse was seen between oral and topical curcumin (P = .56), suggesting that both routes were equally effective. CONCLUSION: Curcumin appears to inhibit skin cancer formation and prolong time to tumor onset when administered by either an oral or topical route. These data suggest that curcumin may have chemopreventive potential against skin cancer, necessitating future experimentation with human subjects.

18F-fluorodeoxythymidine micro-positron-emission tomography versus 18F-fluorodeoxyglucose micro-positron-emission tomography for in vivo minimal residual disease imaging.

OBJECTIVES/HYPOTHESIS: The early detection of persistent/recurrent disease of head and neck squamous cell carcinoma (HNSCC) after treatment can be challenging. The currently used radioisotope (18)F-fluorodeoxyglucose (FDG) is a nonspecific tracer for cancer cells as it detects all metabolically active cells including inflammation. (18)F-fluorodeoxythymidine (FLT) is a radioactive tracer for rapidly proliferating cells, and therefore is more specific for detecting cancer. Our aim was to compare FLT and FDG microPET (positron-emission tomography) to the gold standard in vivo bioluminescence imaging for serial assessment of neoplastic growth in a minimal residual disease in vivo model. STUDY DESIGN: Prospective outcomes research. METHODS: In order to mimic the postsurgical environment of HNSCC patients FaDu cells transfected with a luciferase-expressing retrovirus were inoculated into the skin flap of Balb/c nu/nu mice. Three days later before tumors formed, mice were randomized into (18)F-FLT or (18) F-FDG groups, and microPET imaging was performed on days 3, 6, 10, 18, and 24 after tumor cell inoculation. RESULTS: (18)F-FLT detected tumors as early as day 3 even before tumors were palpable, whereas (18)F-FDG only detected palpable tumors. The average overall normalized radioactivity in the FLT group was significantly higher than the FDG group (P = .025). CONCLUSIONS: (18)F-FLT identified tumor cells before tumors were palpable and can potentially be used for early detection of persistence/recurrence of HNSCC. In addition, this radioisotope can be used to monitor adjuvant therapy with novel targeted therapeutics in preclinical models of persistent disease.

Topical curcumin-based cream is equivalent to dietary curcumin in a skin cancer model.

Skin squamous cell carcinoma (SCC), the most common cancer in the USA, is a growing problem with the use of tanning booths causing sun-damaged skin. Antiproliferative effects of curcumin were demonstrated in an aggressive skin cancer cell line SRB12-p9 (P < 0.05 compared to control). Topical formulation was as effective as oral curcumin at suppressing tumor growth in a mouse skin cancer model. Curcumin at 15 mg administered by oral, topical, or combined formulation significantly reduced tumor growth compared to control (P = 0.004). Inhibition of pAKT, pS6, p-4EBP1, pSTAT3, and pERK1/2 was noted in SRB12-p9 cells post-curcumin treatment compared to control (P < 0.05). Inhibition of pSTAT3 and pERK1/2 was also noted in curcumin-treated groups in vivo. IHC analysis revealed human tumor specimens that expressed significantly more activated pERK (P = 0.006) and pS6 (P < 0.0001) than normal skin samples. This is the first study to compare topical curcumin to oral curcumin. Our data supports the use of curcumin as a chemopreventive for skin SCC where condemned skin is a significant problem. Prevention strategies offer the best hope of future health care costs in a disease that is increasing in incidence due to increased sun exposure.

Efficacy and comparative effectiveness of sirolimus as an anticancer drug.

OBJECTIVES/HYPOTHESIS: To evaluate antitumor efficacy of the generic mammalian target of rapamycin (mTOR) inhibitor sirolimus in preclinical animal models of head and neck squamous cell carcinoma (HNSCC) and compare its effects with those of the patented analogue temsirolimus. STUDY DESIGN: In vivo study. METHODS: To develop xenograft established tumor model (ETM) of HNSCC, FaDu cells were injected subcutaneously into nude mice. When tumors reached 50 to 60 mm(3), mice were randomized into five groups and treated daily intraperitoneally with sirolimus at various doses for 5 days per week for 3 weeks. Tumor volumes were measured. The results were compared with historical data on temsirolimus effects. In the minimal residual disease (MRD) model, surgical wounds were created and FaDu cells implanted. After 72 hours, animals were randomized into two groups and were injected intraperitoneally with 0 or 5 mg/kg sirolimus for 5 days per week for 30 days. RESULTS: In the ETM, sirolimus significantly inhibited tumor growth (P < .01), although there was no overall significant difference in tumor growth inhibition between sirolimus and temsirolimus. In the MRD model, sirolimus significantly suppressed growth of tumors (P < .001) and improved survival compared with controls (P < .01). There was a significant decrease in pS6 expression, indicating mTOR inhibition. CONCLUSIONS: In this study, we demonstrate that the generic mTOR inhibitor sirolimus shows potent antitumor activity in HNSCC and produces comparable effects to the patent drug temsirolimus. Sirolimus has the potential of serving as an economic and comparative targeted agent to temsirolimus in the treatment of HNSCC.

Teasing out the best molecular marker in the AKT/mTOR pathway in head and neck squamous cell cancer patients.

OBJECTIVES/HYPOTHESIS: No reliable molecular biomarker is currently available for clinical application in the management of head and neck cancer patients. The AKT/mTOR pathway is activated in 90% to 100% of head and neck squamous cell cancer (HNSCC) and could be promising biomarkers closely linked to cancer incidence. STUDY DESIGN: Retrospective study of HNSCC and non-cancer patients. METHODS: Oral mucosa from noncancer patients were compared to HNSCC tumors and junctional zone mucosa. The candidate biomarkers mTOR, AKT, 4EBP1, and S6 kinase, signaling components upstream and downstream of mTOR that appear dysregulated in HNSCC, were evaluated using immunohistochemistry (IHC) and Western blot analysis. RESULTS: Expression of phosphorylated AKT and phosphorylated mTOR were significantly higher in cancer patient tumors compared to noncancer oral mucosa samples (P = .004 and P = .026, respectively) by Western blot analysis. Expression of p-mTOR and p-4EBP1 were higher in patient junctional zones compared to tumors (p = 0.017 and p = 0.022, respectively) and no difference in p-AKT or p-S6 expression in HNSCC patients' junctional zone compared to tumors. IHC-demonstrated p-mTOR expression was 81.9% sensitive and 100% specific in differentiating cancer from noncancer mucosa, whereas p-4EBP1 expression by IHC was only 50.0% sensitive and 95.5% specific in differentiating normal mucosa from HNSCC (P < .01). CONCLUSIONS: Phosphorylated mTOR appears to be a reliable biomarker by both Western blot analysis (P = .026) and IHC in human head and neck cancer (P < .001). Moreover, phosphorylated AKT, which is immediately upstream of mTOR, is a potential biomarker that should be further studied. Clinical trials with mTOR inhibitors are being evaluated for HNSCC, and selecting patients that are likely to respond to these inhibitors requires identifying and validating predictive biomarkers of response.

Pharmacodynamic evaluation of temsirolimus in patients with newly diagnosed advanced-stage head and neck squamous cell carcinoma.

BACKGROUND: Activation of the mammalian target of rapamycin (mTOR) pathway in surgical margins of head and neck squamous cell carcinoma (HNSCC) is a predictor of recurrence and patients with minimal residual disease may benefit from adjuvant therapy with temsirolimus, an mTOR inhibitor. METHODS: The effects of 3 weekly doses of 25 mg of temsirolimus on Akt/mTOR pathway biomarkers were evaluated in tumor and peripheral blood mononuclear cells (PBMCs) of patients with HNSCC. Adverse events were assessed. RESULTS: Temsirolimus significantly decreased pS6 and p4E-BP1 in tumors, and pS6 and pAkt in PBMCs (p < .05). There was no significant upregulation of pAkt(Ser(473)) in tumor tissue. Side effects were minimal and reversible. CONCLUSION: Significant inhibition of the mTOR pathway was noted in both tumors and PBMCs of HNSCC with minimal side effects. The mTOR inhibitors can potentially be used as adjuvant therapy for patients with minimal residual disease and PBMCs are potential surrogate markers in this setting.

Comparison of radiosensitizing effects of the mammalian target of rapamycin inhibitor CCI-779 to cisplatin in experimental models of head and neck squamous cell carcinoma.

To determine if the mammalian target of rapamycin (mTOR) inhibitor CCI-779 can sensitize head and neck squamous cell carcinoma (HNSCC) to radiotherapy (XRT) and compare the radiosensitizing effects to cisplatin with its known considerable toxicity. Radiosensitizing effects of CCI-779 were assayed on HNSCC cell lines in vitro. CCI-779 (5 mg/kg), cisplatin (1 mg/kg), and XRT (2 Gy) alone and in combination were evaluated for antitumor activity in mice bearing FaDu and SCC40 xenografts. Effects of CCI-779 on radiation-induced activation of the Akt/mTOR pathway were analyzed. Although CCI-779 did not sensitize HNSCC cells to ionizing radiation in vitro, combination of CCI-779 and XRT significantly augmented the in vivo tumor growth-inhibitory effects of XRT and CCI-779 (P < 0.05). In addition, CCI-779 + XRT suppressed tumor growth more effectively than cisplatin + XRT (P < 0.05). CCI-779 + XRT significantly improved survival compared with XRT alone in both cisplatin-sensitive FaDu (P < 0.01) and cisplatin-resistant SCC40 (P < 0.05) xenograft mice. There were no additional benefits of adding cisplatin to CCI-779 + XRT. CCI-779 significantly attenuated irradiation-induced up-regulation of the mTOR pathway, increased apoptosis and displayed potent antiangiogenic activity in FaDu xenografts that was further enhanced by its combination with XRT (P < 0.05), which may explain the mechanism of its selective radiosensitizing effects in vivo and not in vitro. Antitumor activity of XRT was enhanced when combined with CCI-779 in HNSCC xenograft model. CCI-779 + XRT showed antitumor activity superior to conventional chemoradiotherapy with cisplatin. These results pave the way for clinical trials using molecular targeted therapy with CCI-779 in combination with XRT for HNSCC treatment.

Neuronal apoptosis in neurodegeneration.

Apoptosis mediates the precise and programmed natural death of neurons and is a physiologically important process in neurogenesis during maturation of the central nervous system. However, premature apoptosis and/or an aberration in apoptosis regulation is implicated in the pathogenesis of neurodegeneration, a multifaceted process that leads to various chronic disease states, such as Alzheimer's (AD), Parkinson's (PD), Huntington's (HD) diseases, amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and diabetic encephalopathy. The current review focuses on two major areas (a) the fundamentals of apoptosis, which includes elements of the apoptotic machinery, apoptosis inducers, and emerging concepts in apoptosis research, and (b) apoptotic involvement in neurodegenerative disorders, neuroprotective treatment strategies/modalities, and the mechanisms of, and signaling in, neuronal apoptosis. Current and new experimental models for apoptosis research in neurodegenerative diseases are also discussed.

Apoptosis in acute and chronic neurological disorders.

Programmed cell death or apoptosis is a physiologically important process in neurogenesis wherein approximately 50% of the neurons apoptose during maturation of the nervous system. However, premature apoptosis and/or aberrations in apoptosis control contribute to the pathogenesis of a variety of neurological disorders including acute brain injury such as trauma, spinal cord injury, ischemic stroke and ischemia/reperfusion as well as chronic disease states such as Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis, spinal muscular atrophy, and diabetic neuropathy. The current review will focus on two major topics, namely, the general concepts of our current understanding of the apoptosis death machinery, its mediators and regulation, and the relationship between aberrant apoptosis and genesis of neurodegenerative disorders. This knowledge of apoptosis mechanisms will underpin the basis for development of novel therapeutic strategies and treatment modalities that are directed at control of the neuronal apoptotic death program.

Apoptosis: a key in neurodegenerative disorders.

Apoptosis is an important process in the development of the nervous system. Typically, approximately 50% of the neurons apoptose during neurogenesis before the nervous system matures. However, recent paradigms implicate premature apoptosis and/or aberrations in the fine control of neuronal apoptosis in the pathogenesis of a variety of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, spinal muscular atrophy, stroke, brain trauma, spinal cord injury, and diabetic neuropathy. This review will focus on the current concepts salient to understanding the apoptosis death program, the mediators and control of cellular apoptosis, and the relationship between aberrant apoptosis and genesis of neurodegenerative disorders. The discussion will also highlight current advances in methodology, such as utilization of neuronal cell lines and mutant animal models, in investigations of neuronal apoptotic death. The knowledge of apoptosis mechanisms could underpin the basis for development of novel therapeutic strategies and treatment modalities that are directed at control of the neuronal apoptotic death program.