TP53 mutations in head and neck cancer.

Head and neck squamous cell carcinomas (HNSCCs) arising in the mucosal linings of the upper aerodigestive tract are highly heterogeneous, aggressive, and multifactorial tumors affecting more than half a million patients worldwide each year. Classical etiological factors for HNSCC include alcohol, tobacco, and human papillomavirus (HPV) infection. Current treatment options for HNSCCs encompass surgery, radiotherapy, chemotherapy, or combinatorial remedies. Comprehensive integrative genomic analysis of HNSCC has identified mutations in TP53 gene as the most frequent of all somatic genomic alterations. TP53 mutations are associated with either loss of wild-type p53 function or gain of functions that promote invasion, metastasis, genomic instability, and cancer cell proliferation. Interestingly, disruptive TP53 mutations in tumor DNA are associated with aggressiveness and reduced survival after surgical treatment of HNSCC. This review summarizes the current evidence and impact of TP53 mutations in HNSCC.

Rapalogs induce non-apoptotic, autophagy-dependent cell death in HPV-negative TP53 mutant head and neck squamous cell carcinoma.

TP53 is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSCC). Patients with HPV-negative TP53 mutant HNSCC have the worst prognosis, necessitating additional agents for treatment. Since mutant p53 causes sustained activation of the PI3K/AKT/mTOR signaling pathway, we investigated the effect of rapalogs RAD001 and CCI-779 on HPV-negative mutTP53 HNSCC cell lines and xenografts. Rapalogs significantly reduced cell viability and colony formation. Interestingly, rapalogs-induced autophagy with no effect on apoptosis. Pretreatment with autophagy inhibitors, 3-methyladenine (3-MA) and ULK-101 rescued the cell viability by inhibiting rapalog-induced autophagy, suggesting that both RAD001 and CCI-779 induce non-apoptotic autophagy-dependent cell death (ADCD). Moreover, rapalogs upregulated the levels of ULK1 and pULK1 S555 with concomitant downregulation of the mTORC1 pathway. However, pretreatment of cells with rapalogs prevented the ULK-101-mediated inhibition of ULK1 to sustained autophagy, suggesting that rapalogs induce ADCD through the activation of ULK1. To further translate our in vitro studies, we investigated the effect of RAD001 in HPV-negative mutTP53 (HN31 and FaDu) tumor cell xenograft model in nude mice. Mice treated with RAD001 exhibited a significant tumor volume reduction without induction of apoptosis, and with a concomitant increase in autophagy. Further, treatment with RAD001 was associated with a considerable increase in pULK1 S555 and ULK1 levels through the inhibition of mTORC1. 3-MA reversed the effect of RAD001 on FaDu tumor growth suggesting that RAD001 promotes ACDC in HPV-negative mutTP53 xenograft. This is the first report demonstrating that rapalogs promote non-apoptotic ADCD in HPV-negative mutTP53 HNSCC via the ULK1 pathway. Further studies are required to establish the promising role of rapalogs in preventing the regrowth of HPV-negative mutTP53 HNSCC.

Fibroblast growth factor receptor promotes progression of cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is a keratinocyte-derived invasive and metastatic tumor of the skin. It is the second-most commonly diagnosed form of skin cancer striking 200 000 Americans annually. Further, in organ transplant patients, there is a 65- to 100-fold increased incidence of cSCC compared to the general population. Excision of cSCC of the head and neck results in significant facial disfigurement. Therefore, increased understanding of the mechanisms involved in the pathogeneses of cSCC could identify means to prevent, inhibit, and reverse this process. In our previous studies, inhibition of fibroblast growth factor receptor (FGFR) significantly decreased ultraviolet B-induced epidermal hyperplasia and hyperproliferation in SKH-1 mice, suggesting an important role for FGFR signaling in skin cancer development. However, the role of FGFR signaling in the progression of cSCC is not yet elucidated. Analysis of the expression of FGFR in cSCC cells and normal epidermal keratinocytes revealed protein overexpression and increased FGFR2 activation in cSCC cells compared to normal keratinocytes. Further, tumor cell-specific overexpression of FGFR2 was detected in human cSCCs, whereas the expression of FGFR2 was low in premalignant lesions and normal skin. Pretreatment with the pan-FGFR inhibitor; AZD4547 significantly decreased cSCC cell-cycle traverse, proliferation, migration, and motility. Interestingly, AZD4547 also significantly downregulated mammalian target of rapamycin complex 1 and AKT activation in cSCC cells, suggesting an important role of these signaling pathways in FGFR-mediated effects. To further bolster the in vitro studies, NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice with SCC12A tumor xenografts treated with AZD4547 (15 mg/kg/bw, twice weekly oral gavage) exhibited significantly decreased tumor volume compared to the vehicle-only treatment group. The current studies provide mechanistic evidence for the role of FGFR and selectively FGFR2 in the early progression of cSCC and identifies FGFR as a putative therapeutic target in the treatment of skin cancer.

Endothelial Nox4-based NADPH oxidase regulates atherosclerosis via soluble epoxide hydrolase.

Nox4-based NADPH oxidase is a major reactive oxygen species-generating enzyme in the vasculature, but its role in atherosclerosis remains controversial. OBJECTIVE: Our goal was to investigate the mechanisms of endothelial Nox4 in regulating atherosclerosis. APPROACH AND RESULTS: Atherosclerosis-prone conditions (disturbed blood flow, type I diabetes, and Western diet) downregulated endothelial Nox4 mRNA in arteries. To address whether the downregulated endothelial Nox4 was directly involved in the development of atherosclerosis, we generated mice carrying a human Nox4 P437H dominant negative mutation (Nox4DN), driven by the endothelial specific promoter Tie-2, on atherosclerosis-prone genetic background (ApoE deficient mice) to mimic the effect of decreased endothelial Nox4. Nox4DN significantly increased type I diabetes-induced aortic stiffness and atherosclerotic lesions. Gene analysis indicated that soluble epoxide hydrolase 2 (sEH) was significantly upregulated in Nox4DN endothelial cells (EC). Inhibition of sEH activity in Nox4DN EC suppressed inflammation and macrophage adhesion to EC. On the contrary, overexpression of endothelial wild type Nox4 suppressed sEH, ameliorated Western diet-induced atherosclerosis and decreased aortic stiffness. CONCLUSIONS: Atherosclerosis-prone conditions downregulated endothelial Nox4 to accelerate the progress of atherosclerosis, at least in part, by upregulating sEH to enhance inflammation.

Pro-atherogenic role of smooth muscle Nox4-based NADPH oxidase.

UNLABELLED: Nox4-based NADPH oxidase is a major reactive oxygen species-generating enzyme in the vasculature, but its role in atherosclerosis remains controversial. OBJECTIVE: Our goal was to investigate the role of smooth muscle Nox4 in atherosclerosis. APPROACH AND RESULTS: Atherosclerosis-prone conditions (disturbed blood flow and Western diet) increased Nox4 mRNA level in smooth muscle of arteries. To address whether upregulated smooth muscle Nox4 under atherosclerosis-prone conditions was directly involved in the development of atherosclerosis, mice carrying a human Nox4 P437H dominant negative mutation (Nox4DN), specifically in smooth muscle, were generated on a FVB/N ApoE deficient genetic background to counter the effect of increased smooth muscle Nox4. Nox4DN significantly decreased aortic stiffness and atherosclerotic lesions, with no effect on blood pressure. Gene analysis indicated that soluble epoxide hydrolase 2 (sEH) was significantly downregulated in Nox4DN smooth muscle cells (SMC), at both mRNA and protein levels. Downregulation of sEH by siRNA decreased SMC proliferation and migration, and suppressed inflammation and macrophage adhesion to SMC. CONCLUSIONS: Downregulation of smooth muscle Nox4 inhibits atherosclerosis by suppressing sEH, which, at least in part, accounts for inhibition of SMC proliferation, migration and inflammation.

Role of smooth muscle Nox4-based NADPH oxidase in neointimal hyperplasia.

UNLABELLED: Elevated levels of reactive oxygen species (ROS) in the vascular wall play a key role in the development of neointimal hyperplasia. Nox4-based NADPH oxidase is a major ROS generating enzyme in the vasculature, but its roles in neointimal hyperplasia remain unclear. OBJECTIVE: Our purpose was to investigate the role of smooth muscle cell (SMC) Nox4 in neointimal hyperplasia. APPROACH AND RESULTS: Mice overexpressing a human Nox4 mutant form, carrying a P437H dominant negative mutation (Nox4DN) and driven by SM22α promoter, to achieve specific expression in SMC, were generated in a FVB/N genetic background. After wire injury-induced endothelial denudation, Nox4DN had significantly decreased neointima formation compared with non-transgenic littermate controls (NTg). ROS production, serum-induced proliferation and migration, were significantly decreased in aortic SMCs isolated from Nox4DN compared with NTg. Both mRNA and protein levels of thrombospondin 1 (TSP1) were significantly downregulated in Nox4DN SMCs. Downregulation of TSP1 by siRNA decreased cell proliferation and migration in SMCs. Similar to Nox4DN, downregulation of Nox4 by siRNA significantly decreased TSP1 expression level, cell proliferation and migration in SMCs. CONCLUSIONS: Downregulation of smooth muscle Nox4 inhibits neointimal hyperplasia by suppressing TSP1, which in part can account for inhibition of SMC proliferation and migration.

Resveratrol promotes endothelial cell wound healing under laminar shear stress through an estrogen receptor-α-dependent pathway.

Restenosis is an adverse outcome of angioplasty, characterized by vascular smooth muscle cell (VSMC) hyperplasia. However, therapies targeting VSMC proliferation delay re-endothelialization, increasing the risk of thrombosis. Resveratrol (RESV) inhibits restenosis and promotes re-endothelialization after arterial injury, but in vitro studies assessing RESV-mediated effects on endothelial cell growth contradict these findings. We thus hypothesized that fluid shear stress, mimicking physiological blood flow, would recapitulate RESV-dependent endothelial cell wound healing. Since RESV is an estrogen receptor (ER) agonist, we tested whether RESV promotes re-endothelialization through an ER-α-dependent mechanism. Mice fed a high-fat diet or a diet supplemented with RESV were subjected to carotid artery injury. At 7 days after injury, RESV significantly accelerated re-endothelialization compared with vehicle. In vitro wound healing assays demonstrated that RESV exhibits cell-type selectivity, inhibiting VSMC, but not endothelial cell growth. Under laminar shear stress (LSS), RESV dramatically enhanced endothelial cell wound healing and increased both the activation of extracellular signal-regulated kinase (ERK) and endothelial cell proliferation. Under LSS, small interfering RNA against ER-α, but not endothelial nitric oxide synthase, abolished RESV-induced ERK activation, endothelial cell proliferation, and wound healing. Thus these studies suggest that the EC phenotype induced by LSS better models the prohealing effects of RESV and that RESV and LSS interact to promote an ER-α-dependent mitogenic effect in endothelial cells.

SERCA Cys674 sulphonylation and inhibition of L-type Ca2+ influx contribute to cardiac dysfunction in endotoxemic mice, independent of cGMP synthesis.

The goal of this study was to identify the cellular mechanisms responsible for cardiac dysfunction in endotoxemic mice. We aimed to differentiate the roles of cGMP [produced by soluble guanylyl cyclase (sGC)] versus oxidative posttranslational modifications of Ca(2+) transporters. C57BL/6 mice [wild-type (WT) mice] were administered lipopolysaccharide (LPS; 25 µg/g ip) and euthanized 12 h later. Cardiomyocyte sarcomere shortening and Ca(2+) transients (ΔCai) were depressed in LPS-challenged mice versus baseline. The time constant of Ca(2+) decay (τCa) was prolonged, and sarcoplasmic reticulum Ca(2+) load (CaSR) was depressed in LPS-challenged mice (vs. baseline), indicating decreased activity of sarco(endo)plasmic Ca(2+)-ATPase (SERCA). L-type Ca(2+) channel current (ICa,L) was also decreased after LPS challenge, whereas Na(+)/Ca(2+) exchange activity, ryanodine receptors leak flux, or myofilament sensitivity for Ca(2+) were unchanged. All Ca(2+)-handling abnormalities induced by LPS (the decrease in sarcomere shortening, ΔCai, CaSR, ICa,L, and τCa prolongation) were more pronounced in mice deficient in the sGC main isoform (sGCα1(-/-) mice) versus WT mice. LPS did not alter the protein expression of SERCA and phospholamban in either genotype. After LPS, phospholamban phosphorylation at Ser(16) and Thr(17) was unchanged in WT mice and was increased in sGCα1(-/-) mice. LPS caused sulphonylation of SERCA Cys(674) (as measured immunohistochemically and supported by iodoacetamide labeling), which was greater in sGCα1(-/-) versus WT mice. Taken together, these results suggest that cardiac Ca(2+) dysregulation in endotoxemic mice is mediated by a decrease in L-type Ca(2+) channel function and oxidative posttranslational modifications of SERCA Cys(674), with the latter (at least) being opposed by sGC-released cGMP.

Everolimus downregulates STAT3/HIF-1α/VEGF pathway to inhibit angiogenesis and lymphangiogenesis in TP53 mutant head and neck squamous cell carcinoma (HNSCC).

TP53 mutant head and neck squamous cell carcinoma (HNSCC) patients exhibit poor clinical outcomes with 50-60% recurrence rates in advanced stage patients. In a recent phase II clinical trial, adjuvant therapy with everolimus (mTOR inhibitor) significantly increased 2-year progression-free survival in p53 mutated patients. TP53-driven mTOR activation in solid malignancies causes upregulation of HIF-1α and its target, downstream effector VEGF, by activating STAT3 cell signaling pathway. Here, we investigated the effects of everolimus on the STAT3/HIF-1α/VEGF pathway in TP53 mutant cell lines and xenograft models. Treatment with everolimus significantly inhibited cell growth in vitro and effectively reduced the growth of TP53 mutant xenografts in a minimal residual disease (MRD) model in nude mice. Everolimus treatment was associated with significant downregulation of STAT3/HIF-1α/VEGF pathway in both models. Further, treatment with everolimus was associated with attenuation in tumor angiogenesis and lymphangiogenesis as indicated by decreased microvessel density of vascular and lymphatic vessels in HN31 and FaDu xenografts. Everolimus downregulated the STAT3/HIF-1α/VEGF pathway to inhibit growth and in vitro tube formation of HMEC-1 (endothelial) and HMEC-1A (lymphatic endothelial) cell lines. Our studies demonstrated that everolimus inhibits the growth of TP53 mutant tumors by inhibiting angiogenesis and lymphangiogenesis through the downregulation of STAT3/HIF-1α/VEGF signaling.

Resveratrol and quercetin interact to inhibit neointimal hyperplasia in mice with a carotid injury.

Restenosis is a critical complication of angioplasty and stenting. Restenosis is multifactorial, involving endothelial injury, inflammation, platelet activation, and vascular smooth muscle cell (VSMC) proliferation. Thus, dietary strategies to prevent restenosis likely require the use of more than one agent. Resveratrol (R) and quercetin (Q) are polyphenols that are known to exhibit vascular protective effects. We tested whether R and Q administered in the diet interact to inhibit vessel stenosis in mice with a carotid injury. B6.129 mice were administered a high-fat diet containing 21% fat and 0.2% cholesterol along with R (25 mg/kg), Q (10 mg/kg), or R + Q for 2 wk. A carotid injury was induced and the mice were again administered the enriched diet for 2 wk. Compared with the controls, R significantly decreased stenosis, assessed as an intima:media ratio, by 76%. Although Q treatment alone exhibited no effect, it potentiated the effect of R in that treatment with R + Q significantly decreased the intima:media ratio by 94%. Moreover, this effect was greater than that of R treatment alone (P < 0.05). Although treatments with R, Q, and R + Q significantly affected platelet activation and endothelial function, the responses observed for R + Q were less than additive. Specifically, the effects of R + Q were less than the sum of effects for treatments with R and Q alone. In contrast, treatment with R + Q exhibited more-than-additive effects on inflammatory markers and significant interactions between R and Q were observed. The presence of synergy between R and Q was thus tested in cultures of VSMC and macrophages. Isobolographic analysis revealed that 2:1 molar ratios of R:Q exhibited synergistic inhibition of VSMC proliferation and macrophage chemotaxis. In conclusion, in combination, R and Q can interact to reduce the extent of restenosis, perhaps due to their synergistic inhibition of VSMC proliferation and inflammation.

Inhibition of Fibroblast Growth Factor Receptor Attenuates UVB-Induced Skin Carcinogenesis.

Altered fibroblast GF receptor (FGFR) signaling has been shown to play a role in a number of cancers. However, the role of FGFR signaling in the development and progression of UVB-induced cutaneous squamous cell carcinoma remains unclear. In this study, the effect of UVB radiation on FGFR activation and its downstream signaling in mouse skin epidermis was examined. In addition, the impact of FGFR inhibition on UVB-induced signaling and skin carcinogenesis was also investigated. Exposure of mouse dorsal skin to UVB significantly increased the phosphorylation of FGFRs in the epidermis as well as the activation of downstream signaling pathways, including protein kinase B/mTOR, signal transducers and activators of transcription, and MAPK. Topical application of the pan-FGFR inhibitor AZD4547 to mouse skin before exposure to UVB significantly inhibited FGFR phosphorylation as well as mTORC1, signal transducer and activator of transcription 3, and MAPK activation (i.e., phosphorylation). Moreover, AZD4547 pretreatment significantly inhibited UVB-induced epidermal hyperplasia and hyperproliferation and reduced the infiltration of mast cells and macrophages into the dermis. AZD4547 treatment also significantly inhibited mRNA expression of inflammatory genes in the epidermis. Finally, mice treated topically with AZD4547 before UVB exposure showed decreased cutaneous squamous cell carcinoma incidence and increased survival rate. Collectively, the current data support the hypothesis that inhibition of FGFR in the epidermis may provide a new strategy to prevent and/or treat UVB-induced cutaneous squamous cell carcinoma.

Cutaneous Cancer Biology.

There has been a drastic increase in the incidence of nonmelanoma (NMSC), including squamous, basal cell, and melanoma skin cancers worldwide. Most cases of skin cancer can be treated effectively with surgery; fewer than 10% of cases are advanced and may require additional therapies. A better understanding of the biology of skin cancer will help contribute to better prognostic information and identification of possible new therapeutic targets. Herein, the authors review the biology and pathogenesis of both NMSC and melanoma, focusing on critical cell signaling pathways mediating the disease and current therapeutic strategies targeted to underlying genetic pathways.

Essential role of ER-alpha-dependent NO production in resveratrol-mediated inhibition of restenosis.

Resveratrol (Resv), a red wine polyphenol, is known to exhibit vascular protective effects and reduce vascular smooth muscle cell mitogenesis. Vascular smooth muscle cell proliferation is a critical factor in the pathogenesis of restenosis, the renarrowing of vessels that often occurs after angioplasty and/or stent implantation. Although Resv has been shown to be an estrogen receptor (ER) modulator, the role of the ER in Resv-mediated protection against restenosis has not yet been elucidated in vivo. Therefore, with the use of a mouse carotid artery injury model, our objective was to determine the role of ER in modulating Resv-mediated effects on neointimal hyperplasia. Female wild-type and ER-α(-/-) mice were administered a high-fat diet ± Resv for 2 wk. A carotid artery endothelial denudation procedure was conducted, and the mice were administered a high-fat diet ± Resv for an additional 2 wk. Resv-treated wild-type mice exhibited a dramatic decrease in restenosis, with an increased arterial nitric oxide (NO) synthase (NOS) activity and NO production. However, in the ER-α(-/-) mice, Resv failed to afford protection and failed to increase NO production, apparently because of a decreased availability of the NOS cofactor tetrahydrobiopterin. To verify the role of NO in Resv-mediated effects, mice were coadministered Resv plus a nonselective NOS inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME). Cotreatment with l-NAME significantly attenuated the antirestenotic properties of Resv. These data thus suggest that Resv inhibits vascular proliferative responses after injury, predominately through an ER-α-dependent increase in NO production.

Comparing cell-free circulating tumor DNA mutational profiles of disease-free and nonresponders patients with oropharyngeal squamous cell carcinoma.

OBJECTIVE: The purpose of this study was to investigate whether somatic nonsynonymous variants in tumor tissue can potentially be identified in circulating cell-free DNA (cfDNA) of head and neck oropharyngeal squamous cell carcinoma (OPSCC) patients using next-generation sequencing and can predict recurrence or persistence disease. METHODS: A total of 22 OPSCC patients with tumor tissue and respective plasma samples were included in this study. Matching cfDNA and tumor tissues were processed, and DNA sequencing was conducted using the MiSeq platform. Variants were identified using Biomedical Genomic Workbench and Genialis's online data analysis platform for Swift Biosciences' Accel-amplicon panels. RESULTS: Among 11 nonresponders, 6 matched mutations were detected in 5 patients suggesting a predictive factor for patients with likelihood of recurrence. The matched variants and their allele frequencies identified in the nonresponder group were (tumor DNA/cfDNA in %): TP53 G325fs (27/0.62), TP53 R282W (48/1.74), TP53 R273C (39/2.17), FBXW7 R505G (30/0.6), FBXW7 R505L (31/0.65), and TP53 Q331H (56.5/0.52). Interestingly, the matched somatic mutations were only detected in patients who did not respond to therapy or had persistent disease. CONCLUSIONS: Somatic nonsynonymous variants in tumor tissue can potentially be identified in cfDNA of OPSCC patients using NGS. The likelihood of variant detection in cfDNA is greater in nonresponders, especially in human papillomavirus-negative nonresponders, rendering it beneficial as a less invasive detection method for disease persistence/recurrence and prognosis. LEVEL OF EVIDENCE: Cohort study.

HIV-1 antiretrovirals induce oxidant injury and increase intima-media thickness in an atherogenic mouse model.

A growing body of evidence suggests HIV patients are at a greater risk for developing atherosclerosis. However, clinical investigations have generated conflicting results with regard to whether antiretrovirals are independently involved in the development of HIV-associated atherosclerosis. By administering antiretrovirals in an atherogenic mouse model, we determined whether two commonly prescribed antiretrovirals, the protease inhibitor indinavir and the nucleoside reverse transcriptase inhibitor AZT, can induce premature atherosclerosis. C57BL/6 mice were administered an atherogenic diet+/-AZT, indinavir, or AZT plus indinavir for 20 weeks. Aortic intima-media thickness (IMT) and cross-sectional area (CSA) were determined. Compared to controls, treatment with AZT, indinavir or AZT plus indinavir, significantly increased aortic IMT and CSA. This suggests that antiretrovirals can directly exacerbate atherogenesis, in the absence of interaction with a retroviral infection. To elucidate the role of oxidant injury in the drug-induced initiation of atherosclerosis, a separate group of mice were treated for 2 weeks with an atherogenic diet+/-AZT, indinavir or AZT plus indinavir. Aortic reactive oxygen species (ROS) production and glutathione/glutathione disulfide (GSH/GSSG) ratios, as well as plasma levels of 8-isoprostanes (8-iso-PGF(2alpha)) and lipids were determined. At 2 weeks, aortic ROS was increased and GSH/GSSG ratios were decreased in all antiretroviral treatment groups. Plasma 8-iso-PGF(2alpha) was increased in the AZT and AZT plus indinavir-treated groups. At 20 weeks, increased ROS production was maintained for the AZT and indinavir treatment groups, and increased 8-iso-PGF(2alpha) levels remained elevated in the AZT treatment group. Cholesterol levels were moderately elevated in the AZT and AZT plus indinavir-treated groups at 2 but not 20 weeks. Conversely, indinavir treatment increased plasma cholesterol at 20 but not 2 weeks. Thus, though effects on plasma lipid levels occurred, with effects of the individual antiretrovirals variable across the treatment period, there was consistent evidence of oxidant injury across both early and late time points. Together with the known metabolic abnormalities induced by antiretrovirals, drug-induced oxidant production may contribute to the development of antiretroviral-associated atherosclerosis.

Curcumin gum formulation for prevention of oral cavity head and neck squamous cell carcinoma.

OBJECTIVES/HYPOTHESIS: Head and neck squamous cell carcinoma represents the sixth most common cancer. As a result of field cancerization, second primaries and recurrences are high. Hence, research has focused on chemoprevention. Curcumin, a polyphenol compound with anticarcinogenic properties, is one such promising nutraceutical. As poor bioavailability limits curcumin's use, a novel gum formulation was tested allowing for direct mucosal absorption into the bloodstream. This preliminary study validates curcumin gum efficacy by assessing release and transmucosal absorption, along with measuring its effects on serum cytokine levels. STUDY DESIGN: Clinical trial. METHODS: Protocols consisting of initial chew (chewing gum for 30 minutes) and revised chew (alternating chewing and parking gum against buccal mucosa for 30 minutes) were tested in healthy volunteers. High-performance liquid chromatography measured remnant curcumin in chewed gum, serum, and saliva. Serum levels were assayed for 15 proinflammatory cytokines via multiplex analysis. RESULTS: Revised chew samples demonstrated significantly higher curcumin release and absorption (P = .0078). Curcumin serum levels were significantly higher at 4 hours in samples > 2.0 g of curcumin release (P = .01). As saliva levels decreased, a concurrent increase in serum levels was observed, with no significance in the inverse relationship (P = .1423). When evaluating differences between gender, race, and age, the Asian population showed significantly lower curcumin release and serum levels (P = .009). CXCL1 (GRO-α) and TNF-α were significantly decreased in serum after chewing the gum (P = .036, P < .001, respectively). CONCLUSIONS: Enhanced mucosal contact appears critical in improving curcumin release and absorption. CXCL1 and TNF-α both represent potential biomarkers for the future study of curcumin chemoprevention. LEVEL OF EVIDENCE: 2b Laryngoscope, 129:1597-1603, 2019.

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.

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.

Biomarker and Pathologic Predictors of Cutaneous Squamous Cell Carcinoma Aggressiveness.

OBJECTIVE: Aggressive cutaneous squamous cell carcinoma (cSCC) patients are at increased risk of metastasis. Currently, there are no accepted criteria or biomarkers for reliably predicting individuals at risk for recurrence and metastasis. Our objective is to determine if pS6 and pERK can predict cSCC aggressiveness and to identify primary tumor characteristics that may predict parotid metastasis. STUDY DESIGN: Retrospective case series. SETTINGS: Tertiary care center. SUBJECTS AND METHODS: An Institutional Review Board-approved retrospective review was performed for patients with facial cSCC, with and without metastasis to the parotids. Subjects for the study were identified through the Louisiana Tumor Registry, Veterans Medical Records, and LSU Health-Shreveport pathology database. Tumor specimens from patients with cSCC and cSCC with parotid metastasis were analyzed for pERK and pS6 expression through immunohistochemistry. To identify risk factors for tumor aggressiveness, multiple logistic regression analysis was used to evaluate patients with cSCC that was metastatic to the parotid and managed surgically. RESULTS: cSCC with parotid metastasis specimens exhibited significantly higher average pS6 but not pERK positivity than those from cSCC without metastasis (P < .05). Primary lesion-positive margins (P < .01), size of the skin tumor (P < .01) and degree of tumor differentiation (P < .01) were significantly associated with parotid metastasis. CONCLUSION: Surgical history of cSCC, primary lesion-positive margins, degree of differentiation, and lesion size together with pS6 positivity appear to be predictors of cSCC aggressiveness and should prompt increased monitoring or elective parotidectomy.

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.