Abstract 5272: 3D cell-culture strategy for screening novel agents in Fanconi anemia chemoprevention

Fanconi anemia (FA) patients have DNA repair mutations predisposing them to oral cancers so treatment with non-DNA damaging agents is highly desired. As cancer experimental therapeutics advance towards study paradigms that more carefully mimic physiology, e.g. organoids and spheroids. Presently, we are using a 3D cell culture method emphasizing layers of extracellular matrix (ECM) as FA premalignant lesions retain epithelial architecture. We conducted 3D screening studies using 2 layered geometries: 1) nanofibers coated with 1 ng/mL 2:1 Collagen III/IV (C3C4) then 100 pg/mL 2.75:1 Tenascin C/Fibronectin (TNFN) and 2) polystyrene layered with 50 ug/mL C3C4 then 3.5 ug/mL TNFN. We developed these coatings to maximize lipid raft recovery, a drug transport feature lost in 2D culture. The ECM impact on FA cell drug transport was characterized by comparing effective nuclear delivery of a 20nm nanoencapsulated FITC-labeled RNAi compound (s50-TBG-RNAi3UTR), known to require lipid rafts, to the same oligo formulated with Dotap in a FA HNSCC cell line (FA1). Using confocal microscopy and IMARS software to segment delivery at maximal nuclear intensity into nuclear or endolysosomal compartments, we found, for FA1 cells on ECM, nuclear oligo signal colocalization with nuclear compartment ± coefficient of variation was 62 ± 2.2% for the capsule vs 9.8 ± 8.5% for Dotap oligo. On glass, nuclear delivery was 10 ± 52% for s50 capsule vs 25 ± 32% for Dotap. Endolysosomal compartment sequestration was respectively 28 ± 12, 62 ± 10, 44 ± 19 and 51 ± 15%. This illustrates a relevant decrease in variation in FA cell biology from ECM addition. Next, we studied metformin (Met) and pioglitazone (Pio)(agents in current oral cancer prevention studies) combined with G2/M blockade inhibitors, MK1775 (Wee1 kinase inhibitor) and GSK461364 (PLK inhibitor) in FA1s. Inhibiting G2/M blockade, already induced by FA-derived DNA damage, could promote inappropriate cell division, mitotic catastrophe (MOC) and death. In initial 2D FA1 growth studies, increased death was observed with Met plus MK1775. 3D studies, in contrast, showed increased cell death for FA1s treated with Pio plus either MK1775 or s50-TBG-RNAiCK2 (RNAiCK2). Confocal mechanistic studies in cells plated on ECM and treated for 18 hours, indicated Pio + MK1775 inhibited Survivin and ß-catenin upregulation and FA1 cells did proceed into MOC and death. For Pio (PPARg agonist) + RNAiCK2, RXRa was dephosphorylated at S260, enabling its escape from cytosolic sequestration to bind nuclear PPARg, initiating differentiation. Differentiation was indicated by upregulation panKeratin and Transglutaminase-3. We conclude combination therapies with high interest agents in FA-associated oral cancer can be performed in 3D culture systems and might confirm drug mechanisms of action, thus augmenting other standard methods of cancer drug evaluation and screening (e.g. cell proliferation and clonogenicity).

Citation Format: Gretchen M. Unger, Beverly R. Wuertz, Mary E. Brown, Sanjana Arji, Janeen H. Trembley, Frank G. Ondrey. 3D cell-culture strategy for screening novel agents in Fanconi anemia chemoprevention. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5272.

Metabolic and Metabolomic Effects of Metformin in Murine Model of Pulmonary Adenoma Formation

Epidemiologic studies of diabetic patients treated with metformin identified significantly lower incidences of cancer. From this, there is growing interest in the use of metformin to treat and prevent cancer. Studies have investigated chemopreventive mechanisms including alterations in calorie intake, cancer metabolism, and cell signaling. Repurposing the drug is challenging due to its metabolic effects and non-uniform effects on different types of cancer. In our previously published studies, we observed that benzo[a]pyrene treated mice receiving metformin significantly reduced lung adenomas; however, mice had reduced weight gain. In this study, we compared chemoprevention diets with and without metformin to evaluate the effects of diet vs. effects of metformin. We also performed tandem mass spectrometry on mouse serum to assess metabolomic alterations associated with metformin treatment. In metformin cohorts, the rate of weight gain was reduced, but weights did not vary between diets. There was no weight difference between diets without metformin. Interestingly, caloric intake was increased in metformin treated mice. Metabolomic analysis revealed metabolite alterations consistent with metformin treatment. Based on these results, we conclude that previous reductions in lung adenomas may have been occurred from anticancer effects of metformin rather than a potentially toxic effect such as calorie restriction.

Observations of increased gastroesophageal reflux symptomology in an anhydrous ammonia exposed population

OBJECTIVE

This case series describes a cohort of patients exposed to anhydrous ammonia vapors with clinical findings of laryngopharyngeal reflux (LPR). The study characterizes the identification of LPR as a consequence of vapor inhalation and the utility of PPI therapy in LPR secondary to inhalational ammonia exposure.

METHODS

This is a case series of 15 patients exposed to anhydrous ammonia from a single chemical spill who experienced LPR several months after exposure. Symptoms of LPR were assessed at their initial consultation and by phone at least 30 days after treatment with low-dose PPI or diet modification. At this visit, patients underwent complete head and neck examination and flexible direct laryngoscopy.

RESULTS

15 patients were available for analysis before and after treatment. 93.3 % experienced at least three cardinal symptoms of LPR. 66 % of these patients had at least one LPR finding on flexible laryngoscopy. 73 % were treated with daily standard dose PPI, and 82 % of these patients experienced reduction of symptoms after 30 days of PPI treatment. Four of 15 patients were not taking the PPI as prescribed, and only one of these patients had resolution of LPR symptoms.

CONCLUSION

We conclude that there is an association between anhydrous ammonia exposure and the development of LPR symptoms. In this study, treatment with PPIs was successful in reducing symptoms for most patients, and patients who did not receive PPIs experienced symptoms for a longer time.

Effects of methylene blue photodynamic therapy on oral carcinoma and leukoplakia cells

Objective

Methylene blue (MB) is a readily available and affordable substrate that can be used as a photosensitizer for photodynamic therapy (PDT). The objective of this study was to determine if PDT with MB can downregulate matrix metalloproteinases (MMPs) related to oral carcinoma.

Methods

Cell cultures of oral squamous cell carcinoma (CA‐9‐22), oral leukoplakia (MSK‐Leuk1), and immortalized keratinocytes (Rhek‐1A) were photosensitized with MB and treated with PDT. MMP‐9 gene expression was interrogated via qRT‐PCR. The 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay was used to confirm the efficacy of MB PDT.

Results

MMP‐9 gene expression was found to be significantly decreased in oral carcinoma, leukoplakia, and immortalized keratinocytes with use of MB PDT.

Conclusion

This work demonstrates that MB‐mediated PDT can downregulate MMPs which are critical to the invasion and metastasis of oral cancer. These results suggest that MB PDT could be a clinically significant and cost‐effective treatment for oral leukoplakia and carcinoma.

Level of Evidence

NA

Abstract 6306: Genomic analysis markers of stemness in oral cancer progression

Introduction: In clinical cancer treatment there is an continuing effort to identify limited gene sets from high dimensional data to predict risk, treatment response, etc. Oral carcinogenesis is a multistep process of mutations, disordered growth, and the development of invasion. In the oral cancer milieu, inflammation and stemness has been demonstrated to be cooperative during carcinogenesis. We hypothesized that differences in inflammation, stemness, and EMT might distinguish lesion and adjacent normal mucosa in our RNA Seq data on preneoplastic lesions. Once candidate genes are identified they might be applied to other oral mucosal specimens to identify risk for malignancy development.

Materials and Methods: We collected lesion and adjacent normal mucosal tissues from 16 subjects with high risk leukoplakia and early oral cancer (T1N0 and T2N0). Sequencing libraries were generated using the Illumina Truseq Stranded mRNA library prep kit. Sequencing was performed on an Illumina Hiseq 3000 instrument with paired-end 75bp read and sequenced to an overall depth of 30 million reads per sample.

Results: After developing a biospecimen collection procedure that functions in the senior author’s clinic flow, we were able to isolate sequenceable total RNA from 100% of the specimens we collected. We identified several hundred differentially expressed genes between lesion and adjacent normal. With regard to stemness, inflammation, and EMT we multiple candidate genes that could be incorporated into a limited gene set for further studies. Aldehyde dehydrogenase family members were of particular interest in the stemness candidate genes, for example. ALD 1A1 and ALD 3B1, were significantly upregulated in lesion versus normal (P< 0.02).

Conclusions: We conclude there are differentially expressed inflammatory, EMT, and stemness in oral preneoplastic specimens. We have identified multiple candidate genes that could be assembled into a limited gene panel (12-24 genes) for further studies of oral cancer risk in mucosal lesions

Citation Format: Gretchen Unger, Beverly G. Wuertz, Patrick Gaffney, Frank G. Ondrey. Genomic analysis markers of stemness in oral cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6306.

Large cell neuroendocrine carcinoma originating in the subglottic larynx

Large cell neuroendocrine carcinoma (LCNEC) of the larynx is an exceedingly rare cancer of the head and neck that is difficult to diagnose. Few case reports of laryngeal LCNEC exist within the literature, and it was not until recently that LCNEC was recognized as a discrete subtype of neuroendocrine carcinoma. Given its recent recognition as a distinct subtype, histologic characteristics distinguishing LCNEC from other poorly differentiated carcinomas remain under investigation. Various reports have shown genetic alterations such as p53 and/or p16 overexpression, which are typically associated with infection by human papilloma virus (HPV). However, some reports have shown p53 and/or p16 overexpression in HPV negative samples. In this case, we discuss a 67-year-old patient with a history of extensive alcohol and tobacco use with a newly diagnosed T4N0M0, high grade, LCNEC of the subglottic larynx. Tumor pathology demonstrated positive staining for typical neuroendocrine (NE) markers like synaptophysin and chromogranin A; however, there was diffuse CK34βE12 and p16 expression. LCNEC is a newly classified subtype of poorly differentiated neuroendocrine (NE) tumors, and the diagnosis requires consideration of the clinical presentation, microscopic features, and immunostaining markers.

Patients with oral preneoplastic lesions and integration of dental pathology referrals

PURPOSE

Oral cancers lack standardized monitoring systems. Our institution has developed an active surveillance system which provides detailed monitoring and follow up of patients with oral preneoplastic lesions (OPL). We examined a historic cohort of patients with OPL seen by regional dental professionals and a current cohort of clinic patients. The major aim was to examine follow up practices for biopsy proven dysplasia to gauge appropriateness of an active monitoring system for oral carcinoma.

MATERIALS AND METHODS

Questionnaires regarding patients with OPL were sent to 285 dentists who had requested oral pathology services from our institution. The follow up practices of 141 dentists were evaluated for patients with OPL. We then examined our current clinic referral patterns for the number of dental referrals after the creation of an oral carcinoma active surveillance clinic.

RESULTS

There were 76.5% (108/141) of patients who received follow up after diagnosis of preneoplastic oral lesions with 14.1% who underwent repeat biopsy. There was a malignant transformation rate of 11.3% including transformation of 42.8% of severe dysplasias into carcinoma within 2 years. After establishment of a dental referral clinic, 21.8% of tumor visits in a six-week period were referred from the regional dental community.

CONCLUSIONS

A high rate of transformation of OPL to cancer in this cohort may support a role for joint dental and otolaryngology surveillance of dysplasia with longitudinal follow up.

Preclinical evidence for pioglitazone and bexarotene combination in oral cancer chemoprevention

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) requires new treatments and targeted approaches to improve survival. The peroxisome proliferator-activated receptor γ (PPARγ) and retinoic X receptor alpha (RXRα) nuclear receptor pathways may be targetable with repurposed Food and Drug Administration (FDA)-approved agents for prevention and treatment.

METHODS

Oral cancer and leukoplakia cell lines were treated with the PPARγ agonist (pioglitazone) and RXRα activator (bexarotene). PPARγ activation, cellular proliferation, apoptosis activity and phenotype, including the pharmacodynamic marker, involucrin (IVL), were subsequently analyzed using a reporter gene assay, genomic data, MTT assay and western blot.

RESULTS

Microarray analysis of HNSCC tumor versus normal tissue shows IVL expression is significantly increased in normal tissue compared to HNSCC tumors (p < 0.0001). In MSK Leuk1 and CA 9-22 cell lines, pioglitazone increases PPARγ DNA binding activity and IVL promoter activity in a dose dependent manner (p < 0.01 and p < 0.0001). Combination treatment with pioglitazone and bexarotene increases PPARγ DNA binding activity and IVL promoter activity (p < 0.01 and p < 0.0001). MTT analysis shows decreases in cell proliferation when cells are treated with pioglitazone and bexarotene. Decreases in cell proliferation are significant to at least p < 0.05 for all combination versus single agent treatments. Western blot on whole-cell lysate from cells treated with pioglitazone and bexarotene alone or in combination for IVL showed increased protein levels with combination treatment.

CONCLUSIONS

Targeting the PPARγ/RXRα heterodimer with pioglitazone and bexarotene was effective in this preclinical project. This was functional in both preneoplastic and oral cancer cell lines. A better understanding of the molecular mechanism on downstream effects on cellular proliferation could potentially have implications clinically, both in oral preneoplasia and possibly head and neck cancer; however, more research needs to be done to explore the potential these medications have in chemoprevention.

Abstract P199: Tenfibgen nanoencapsulated RNAi feCK2 inhibits protein kinase CK2 and induces apoptosis in feline oral squamous cell carcinomas in vivo

In an initial safety evaluation in domestic cats suffering from oral squamous cell carcinomas (FOSCC), nine cat subjects were treated IV with 5-6 doses given twice weekly of s50 RNAi feCK2 at either 2 or 20 ug/kg (Cannon et. al., Hu Gene Ther Clin Devel 28(2):80-6, 2017). Treatment was generally well tolerated. In one case, a clear drug-related Grade 3 side effect was rapid tumor death (tumor lysis) resulting in an open wound. This issue has been addressed successfully in separate mice studies with longer, lower-dose SQ regimens. Protein kinase CK2, as a promising target in oncology, plays vital roles in cell growth, proliferation, and suppression of apoptosis (Ahmed et al., Trends Cell Biol 12: 226-30, 2002). Anti-feCK2aa’ is a tumor-targeted 20 nm crystalline capsule bearing single-stranded RNAi oligos against both CK2 catalytic kinase subunits with a ligand-coated shell derived from Tenascin-C (tenfibgen). Tenascin-C is upregulated in multiple solid tumors and is present in tumors throughout their lifecycle. The capsule’s ultrasmall size enables efficient raft-mediated delivery of oligos to the perinuclear space of the target cell, and the ability to reach metastases without reliance on EPR (Unger et. al, Mol Cancer Ther 13:2018-29, 2014). Initial mechanistic work focused on changes in clinically scored IHC of the CK2a subunit in study tumors. In an effort to develop a future working hypothesis, remaining paraffin-embedded tissues were retrospectively examined for both kinase subunits of CK2 as a mixture (CK2aa’), cleaved PARP (CP, apoptosis marker) and Ago2 (critical enzyme required for RNAi drug activity). Previous work in murine models showed variation of Ago2 levels in primary human and xenograft tumors. Further, model xenograft and syngeneic tumors responded with increased Ago2 levels and drug activity upon 10 mg/ml IV priming followed by low-dose SQ treatment (Cancer Res 2016;76(14 Suppl):3746). Using confocal fluorescence microscopy, we observed that decreased post-treatment CK2aa’ and increased CP corresponded positively with clinical tumor responses while non-responders showed an inverse relationship. Examination of arrayed human HNC samples also showed a variation in Ago2 levels but premalignant oral lesions from a human chemoprevention trial did not. These observations suggest a possible future path for feline patient therapy of advanced lesions using Ago2 stratification, potential IV priming and more convenient, longer-term SQ dosing administered by feline caregivers. A path for human therapy may lie through chemoprevention with much to be learned from feline studies. Funding: University of Minnesota Clinical and Translational Sciences Award (1UL1 RR033183-01), NIH SBIR Contract HHSN26120 1300030C, N01-CN-15000, Mod#5, V.A. Merit Review research funds (BX00173 and BX003282) and NCI Award CA150182.

Citation Format: Frank G. Ondrey, Gretchen M. Unger, Claire M. Cannon, Janeen H. Trembley, BT Kren, Jaime F. Modiano, Khalil Ahmed. Tenfibgen nanoencapsulated RNAi feCK2 inhibits protein kinase CK2 and induces apoptosis in feline oral squamous cell carcinomas in vivo [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P199.

An active surveillance program in oral preneoplasia and translational oncology benefit

OBJECTIVE

We desired to establish an active surveillance clinic for head and neck cancer. In this review we examined.

METHODS

We examined the natural history of human oral carcinogenesis, the types of preneoplastic lesions, and efforts at oral chemoprevention over the past decades for presentation here.

RESULTS

We established a clinic and program for patients with oral premalignant lesions approximately over 15 years ago based on an unmetneed for this service. We have completed over 4000 outpatient visits for this cohort and have a place for referrals of difficult oral lesions. We have leveraged this population for multiple federally funded trials on oral cancer prevention as well as specimen banking.

CONCLUSION

There is need for routine active surveillance for oral preneoplastic conditions in patients at high risk for conversion to cancer. There are no effective durable treatment or preventions for these individuals and we have attempted to fill this unmet need with our program.

Inhibition of mTOR signaling and clinical activity of metformin in oral premalignant lesions

BACKGROUND

The aberrant activation of the PI3K/mTOR signaling circuitry is one of the most frequently dysregulated signaling events in head and neck squamous cell carcinoma (HNSCC). Here, we conducted a single-arm, open-label phase IIa clinical trial in individuals with oral premalignant lesions (OPLs) to explore the potential of metformin to target PI3K/mTOR signaling for HNSCC prevention.

METHODS

Individuals with OPLs, but who were otherwise healthy and without diabetes, underwent pretreatment and posttreatment clinical exam and biopsy. Participants received metformin for 12 weeks (week 1, 500 mg; week 2, 1000 mg; weeks 3–12, 2000 mg daily). Pretreatment and posttreatment biopsies, saliva, and blood were obtained for biomarker analysis, including IHC assessment of mTOR signaling and exome sequencing.

RESULTS

Twenty-three participants were evaluable for response. The clinical response rate (defined as a ≥50% reduction in lesion size) was 17%. Although lower than the proposed threshold for favorable clinical response, the histological response rate (improvement in histological grade) was 60%, including 17% complete responses and 43% partial responses. Logistic regression analysis revealed that when compared with never smokers, current and former smokers had statistically significantly increased histological responses (P = 0.016). Remarkably, a significant correlation existed between decreased mTOR activity (pS6 IHC staining) in the basal epithelial layers of OPLs and the histological (P = 0.04) and clinical (P = 0.01) responses.

CONCLUSION

To our knowledge this is the first phase II trial of metformin in individuals with OPLs, providing evidence that metformin administration results in encouraging histological responses and mTOR pathway modulation, thus supporting its further investigation as a chemopreventive agent.

TRIAL REGISTRATION

NCT02581137

FUNDING

NIH contract HHSN261201200031I, grants R01DE026644 and R01DE026870

Abstract 2568: Use of kinase inhibitors in Fanconi anemia oral cancercell lines

Successful Fanconi anemia (FA) treatment allows greater longevity for these patients. However, there is a greatly increased risk of squamous malignancies of the head and neck which are quite deadly in these young patients. There is an unmet need for non DNA damaging therapies for this malignancy which could augment surgery. Our approach has been to examine potential treatments based on known pathophysiology of the disease which would be acceptable for this population so we examined the effects of metformin and pioglitazone, as well as two cell cycle kinase inhibitors, in FA and leukoplakia cell lines. We examined dose-dependent and combination effects on cell proliferation, as judged by MTT assay. We examined metformin, pioglitazone, the polo-like kinase 1 inhibitor, GSK461364, and Wee1 kinase inhibitor, AZD1775.In single agent studies, we observed dose-dependent decreases in cell proliferation with all 4 single agents. We observed decreased cell proliferation in all cell lines at 72 hours at clinically achievable serum levels of 85% to 55% of control levels (P&lt;0.0001). Additionally, we found decreases beyond single agent treatment levels when cells were treated with metformin combined with GSK461364 or AZD1775 and similarly, with combination therapies of pioglitazone and GSK461364 or AZD1775. Our current data demonstrate feasibility and preclinical efficacy of a combined agent approach for FA associated head and neck cancer. The low reported toxicity of these agents clinically allows for all of these agents to potentially move forward clinically, once additional experiments are conducted in mechanistic and animal studies.

Citation Format: Walter N. Jungbauer, Mustafa M. Ali, Beverly R. Wuertz, Frank G. Ondrey. Use of kinase inhibitors in Fanconi anemia oral cancercell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2568.

Abstract 2590: Genomic analysis points to fibrosis and changes in fat metabolism in oral cancer progression

Head and neck cancer long term survival has only experienced marginal gains over the past 3 decades. Further, there is inadequate understanding of the biology of carcinogenesis and recurrence, as well as its relation to the microenvironment. Deeper understanding of these areas would provide improved molecular target identification. In pursuit of this goal, a small clinical trial collected lesion and adjacent normal-appearing mucosa for subsequent RNA-seq analysis. Patients were grouped by post-surgical pathology as either precancer (hyperplasia - severe dysplasia) or cancer (carcinoma in situ - early stage invasive cancer). Following identification of differentially expressed (DE) genes, DE genesets were submitted for Ingenuity Pathway Analysis (IPA). Hierarchical clustering illustrates distinct separation between lesion and perilesional normal mucosa of the top 100 DE genes. Among the top 25 dysregulated pathways, 50% were associated with creation of fibrotic tumor microenvironment (TME), 20% were related to changes in immune populations inhabiting the TME and 10% devoted to metabolism changes. Subgroup analysis, (precancer vs. cancer), revealed dysregulation of metabolism (~50%) predominating in precancer. Metabolism remained an important dysregulation at 30% of the top 25 pathways in cancer. Protein network analysis, (Metascape on-line tool), confirmed IPA results, illustrating an extensive, previously undescribed, interconnectedness of fibrosis with shifts in fatty acid metabolism from oxidative to gluconeogenesis, providing a foundation for choosing targets amenable to cancer prevention. Several notable pathways are likely contributed to by inflammatory and other cells in the milieu, not precancer cells themselves. So, we dove deeper, using EpIC (Epitope Immunogenicity Characterization) algorithm to assess relative percentages of non-tumor cells based on 20-count gene signatures. Gene expression favored a profile of significantly increasing cancer-associated fibroblasts, decreasing CD-8 killer T cells, and increasing vascular endothelial cells during progression, with macrophage content slightly increasing in cancer specimens. These findings suggest interaction between immunoinflammatory milieu and precancerous cells promoting malignancy. Several high yield target pathways are related to published mechanisms of action for drugs of high interest to our cancer prevention program (pioglitazone/metformin). Further, we confirmed protein network analysis in an additional oral carcinoma dataset from Conway et. al, (Oncotarget 2015).

Citation Format: Gretchen M. Unger, Beverly R. Wuertz, Charles L. Pruett, Matthew Watkins, Patrick M. Gaffney, Frank G. Ondrey. Genomic analysis points to fibrosis and changes in fat metabolism in oral cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2590.

Genomic Database Analysis for Head and Neck Cancer Prevention Targets: MTOR Signal Transduction Pathway

BACKGROUND

Type II diabetes agents have anticancer effects on head and neck squamous cell carcinoma (HNSCC). The mechanistic target of rapamycin (MTOR) pathway represents a putative target.

MATERIALS AND METHODS

We interrogated an Affymetrix HNSCC dataset for MTOR-related gene expression.

RESULTS

MTOR expression itself was unchanged, but various related genes demonstrated differential expression. Pathway promoters ras homolog (RHEB), MTOR-associated protein (MLST8), and ribosomal protein S6 kinase B1 (RPS6KB1) were up-regulated. Expression of growth suppressors tuberous sclerosis complex 2 (TSC2), programmed cell death 4 (PDCD4), and BCL2 apoptosis regulator-associated agonist of cell death (BAD) were reduced in HNSCC. Upstream, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), AKT serine/threonine kinase 1 (AKT1), and phosphatase and tensin homolog (PTEN) were up-regulated in cancer.

CONCLUSION

Several MTOR pathway promoters and tumor suppressors were found to be differentially expressed, favoring MTOR pathway up-regulation in HNSCC. Genomic databases can be interrogated to identify intervention targets and endpoints in HNSCC trials.

Abstract 23: Precision medicine approaches to Fanconi anemia oral cancer personalized prevention and treatment

There is an increased risk of oral cavity and other head and neck cancers as Fanconi patients live longer post transplantation. DNA repair defects in Fanconi patients contribute to “field effect” in this population, which causes frequent recurrences and often fatal, second primary oral malignancies. These developments show a need for translation of new basic science concepts for this patient population. We are examining the effects of both Metformin and Pioglitazone, and Polo kinase and Wee Kinase inhibitors in Fanconi anemia oral cancer cell lines, and leukoplakia control cells.

We employed 3 FA oral cancer cell lines for the current study. We performed clonogenic and cell proliferation (MTT) experiments in replicates and repeated those experiments to establish initial dose responses of the inhibitors at biologically relevant concentrations. We used ANOVA analysis with a P&lt;0.05 as our level of significance. Concurrently, we are examining pioglitazone-metformin signaling pathways in biopsies from precancerous oral lesion (non-FA) patients treated with pioglitazone in our multiple chemoprevention clinical trials via confocal fluorescence microscopy.

We found both the Wee Kinase inhibitor and POLO kinase inhibitor resulted in dose dependent decreases in proliferation and clonogenic potential in several experiments in all cell lines. We observed decreased proliferation at 72 hours at clinically achievable serum levels of 75%. However, we also observed cytotoxic effects as well, as judged by MTT reading at 72 hours being lower than the original Day 0 MTT readings. Pioglitazone treatment also resulted in dose dependent decreases in cell proliferation and clonogenic potential at clinically achievable serum levels. Similar effects can be achieved with metformin, however, at higher doses. Additionally, we have identified surrogate endpoints as suitable pharmacodynamic readouts by IHC analysis of the cell lines.

There are precision medicine treatments for FA-associated oral carcinoma and these are feasible, based on earlier promising results we present here. We are attempting to discover new treatment methodologies for these patients, as conventional agents and radiation therapy are often unacceptable, due to the DNA fragility of the patient population. In combination, these efforts support our future goals of chemoprevention in this underserved prevention population.

Citation Format: Daniel K. Swenson, Beverly R. Wuertz, Mustafa M. Ali, Gretchen M. Unger, Frank G. Ondrey. Precision medicine approaches to Fanconi anemia oral cancer personalized prevention and treatment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 23.

Abstract LB-251: Investigation of few-shot deep learning techniques on a small, high dimensional head and neck carcinoma dataset for prediction of cancer recurrence

Introduction: Artificial Intelligence (AI) techniques may be useful in predictive oncology. We examined the feasibility of applying open source Few-shot learning to genomics data for the purpose of predicting head and neck cancer recurrences. We compared basic feed forward neural networks (vanilla networks) to a special architecture designed for few-shot learning called a Siamese network. Methods: Affymetrix U133A gene chip data (D=22,215, 41 tumor/13 normal) of patients with non-recurrent (46.34%) and recurrent (53.66%) head and neck carcinomas (nRHNC and RHNC, respectively) was analyzed. Shallow (one-layer) and deep (three-layer) variants were examined for both vanilla and Siamese networks to predict RHNC using the PyTorch framework. Four models were built using PyTorch: one shallow vanilla (SV) network with a single layer of 100 neurons, based on the top performing model from the authors' previous work, one deep vanilla (DV) network with layers of 256, 64, and 8 neurons, one shallow Siamese (SS) network with a single layer of 100 neurons, and one deep Siamese (DS) network with layers of 256, 64, and 8 neurons. Each model was initialized, trained, and evaluated 11 times. Kaiming initialization and Stochastic Gradient Descent with Nesterov Momentum (0.5) was employed with typical assumptions. Results: The model with the highest mean F1 score, AUC, and sensitivity was the SV network (0.7001, 0.6667, and 0.6800 respectively) the model with the highest sensitivity was DV (0.7217). When comparing the mean metrics for the following pairs: SV/DV, SS/DS, SV/SS, and DV/DS, the only difference of means that were found to be statistically significant was the SV/SS pairing for F1, AUC, and specificity. Conclusion: The simplest model, with the least representational capacity, performed best but not in a statistically significant manner in nearly all cases. Interestingly, the DS model performed better than the SS model AUC and specificity while the SV model performed better than its deep counterpart in those metrics. In this initial analysis, we conclude that it is feasible to apply PyTorch AI to Affymetrix gene chips to obtain meaningful data about head and neck cancer recurrences.

Citation Format: Frank G. Ondrey, Dalton Schutte. Investigation of few-shot deep learning techniques on a small, high dimensional head and neck carcinoma dataset for prediction of cancer recurrence [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-251.

Pioglitazone, Nuclear Receptors, and Aerodigestive Prevention

There has been intense interest in nuclear receptor targeting for cancer prevention. With the exception of estrogen antagonism in breast carcinoma there has not been widespread adoption or success of this strategy in clinical cancer prevention. Keith and colleagues have performed a careful study, which utilized the PPARγ nuclear receptor agonist, pioglitazone, a common type II diabetes agent, in subjects at risk for lung carcinoma. Although the results are not promising with this strategy, the study provides evidence for feasibility accrual and biomarker strategies that could be utilized to gain additional insight in future trials.

Abstract 658: Antiproliferative effects of type II diabetes agents in Fanconi derived oral squamous carcinoma

Fanconi anemia is a rare disease characterized by bone marrow failure requiring transplantation at a young age. Patients with Fanconi Anemia are at risk for the development of squamous cell carcinomas of the skin and mucosal surfaces at risks several hundred fold higher than control populations and these malignancies can pursue an aggressive, often fatal, course. Our group has been interested in repurposing Type 2 diabetes agents for oral cancer prevention and treatment. Presently, we examined the effects of the thiazolidinedione drug, pioglitazone, and an experimental biguanide, N1-hexyl-N5-benzyl-biguanide (HBB), on the proliferation of Fanconi-derived oral carcinoma cells. We incubated MOP FA1,a, VU-1131, and VU-1365 b, and C squamous cell carcinoma cell lines with vehicle controls or the thiazolidinedione pioglitazone or biguanide (HBB). We found dose-dependent decreases in cellular proliferation in all three Fanconi-derived cell lines at physiologically relevant concentrations (10 - 50 µM) after 1 to 3 days in several experiments. The effects were not due to simple cytotoxicity as judged by trypan blue staining. In other non-squamous cell lines of cervical and oral cavity origins we have previously discovered similar effects. These agents affect PPAR gamma associated pathways (pioglitazone) or mTOR and mitochondrial glucose metaboliscm pathways (HBB). Since Fanconi anemia patients are highly susceptible to DNA damaging effects of cytotoxic chemotherapy, these classes of agents might be attractive in Fanconi Anemia oral cancer treatment or prevention. Metformin, another biguanide, is currently postulated to delay bone marrow failure in the Fanconi population and is currently in use in an early phase clinical trial. Our results may, therefore, be attratciveattractive for oral cancer prevention and treatment in this population, as they are well tolerated. Further examination of molecular mechanisms will likely generate putative pharmacodynamics markers for future clinical trials.

Citation Format: Kim Miller, Beverly Wuertz, David Potter, Frank G. Ondrey. Antiproliferative effects of type II diabetes agents in Fanconi derived oral squamous carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 658.

Chemoprevention of Lung Carcinogenesis by Dietary Nicotinamide and Inhaled Budesonide

Nicotinamide, the amide form of vitamin B3, and budesonide, a synthetic glucocorticoid used in the treatment of asthma, were evaluated to determine their individual and combinational chemopreventive efficacy on benzo(a)pyrene-induced lung tumors in female A/J mice. Nicotinamide fed at a dietary concentration of 0.75% significantly inhibited tumor multiplicity. Nicotinamide by aerosol inhalation at doses up to 15 mg/kg/day did not result in a statistically significant reduction in tumor multiplicity. Finally, dietary nicotinamide was administered with aerosol budesonide and tumor multiplicity reduced by 90% at 1 week and 49% at 8 weeks post last carcinogen dose. We conclude nicotinamide is an effective and safe agent for lung cancer dietary prevention at both early- and late-stage carcinogenesis and that efficacy is increased with aerosol budesonide. Combination chemoprevention with these agents is a well-tolerated and effective strategy which could be clinically advanced to human studies.

PPARγ-Mediated p21 Induction in Aerodigestive Preneoplastic Cell Lines

INTRODUCTION

Oral leukoplakia is defined as a mucous membrane disorder characterized by white patches that cannot be scraped off. Leukoplakia is the most frequent, potentially premalignant oral mucosa disorder and a good candidate for chemopreventive therapies. Pioglitazone activates peroxisome proliferator-activated receptor gamma (PPARγ), which forms a complex with nuclear cofactors and regulates gene expression of a variety of cell-cycle proteins and is currently being tested preclinically and clinically in aerodigestive cancer prevention.

METHODS

In the present study, we hypothesized that pioglitazone would decrease proliferation of human leukoplakia cells (MSK Leuk1) and transformed bronchial epithelial cells (BEAS-2B) through regulatory changes of G1 checkpoint protein regulators, p21 and cyclin-D1. MSK Leuk1 and BEAS-2B cells were treated with pioglitazone and assayed for cell proliferation and p21 transcriptional activity.

RESULTS

We discovered pioglitazone significantly inhibited cell proliferation in a dose-dependent fashion. We also observed p21 protein induction after treatment with pioglitazone, which was preceded by measurable increases in p21 mRNA induction.

CONCLUSIONS

We conclude the PPARγ activator, pioglitazone, can activate p21, which is associated with decreased proliferation in 2 aerodigestive preneoplastic cell lines. In addition, the p21 gene may be a potential hypothesis-driven biomarker in translational studies of pioglitazone as a chemoprevention agent for aerodigestive cancer.

Abstract 4985: M4OC-Prevent: Clinical evaluation of metformin for oral cancer precision prevention

Despite encouraging recent results from novel treatment options, such as immunotherapy, for head and neck squamous cell carcinoma (HNSCC), limited progress has been made in improving outcomes for most patients. Prevention and early detection are key to improving the prognosis of HNSCC. We have previously shown that persistent activation of the PI3K/mTOR signaling circuitry is the most frequent dysregulated signaling mechanism in HNSCC, and that PI3K/mTOR inhibition exerts potent antitumor activity in a large series of genetically-defined and chemically-induced HNSCC models. However, potential immunosuppression and other dose-dependent side effects raise concerns regarding long term use of PI3K/mTOR inhibitors as chemopreventive agents. The repurposed drug metformin, used for frontline treatment of type 2 diabetes, decreases mTOR signaling in HPV- and HPV+ experimental HNSCC models and displays potent chemopreventive activity in mouse oral-premalignancy models. Furthermore, two recent large retrospective case-control cohort studies involving more than 300,000 diabetic patients demonstrated a decreased HNSCC risk in patients using metformin. Therefore, we conducted a single-arm, open label phase IIa clinical trial (NCT02581137) in individuals with oral premalignant lesions (OPL; oral leukoplakia or erythroplakia) to explore the potential of metformin for HNSCC prevention. Subjects were eligible if they had an OPL at any site with dysplasia or hyperplasia not associated with mechanical factors, and were otherwise healthy, without diabetes. They underwent pre- and post-treatment clinical exam of the oral cavity with lesion measurement and biopsy, along with saliva and blood collection. Eligible participants received metformin for 12 weeks (500 mg per day for the first week, 1,000 mg per day for the second week, and then 2,000 mg per day for the remaining treatment period). 26 participants were accrued and 22 were assessable for response. The toxicity profile was consistent with the known side effect profile of metformin. The clinical response rate was 18%, lower than the 30% spontaneous regression rate documented in several published long term oral leukoplakia trials. The clinical progression rate was also 18%. The significance of the clinical response assessment was limited by the short duration of treatment (only 12 weeks). Of interest, however, the histologic response rate was 59%, including 13% complete responses, and the histologic progression rate was 18%. Most of the responses consisted of a one grade improvement in histology. Circulating and tissue biomarker analyses, the latter focused on the impact of metformin on the AMPK-mTOR signaling network, are being analyzed. The goal of our studies is to provide a mechanistic framework for the selection of patients who may benefit from metformin for precision prevention of oral cancer.

Citation Format: J Silvio Gutkind, Frank G. Ondrey, Denise Laronde, Miriam Rosin, Alfredo A. Molinolo, Charles Coffey, Beverly R. Wuertz, Leigha D. Rock, Huyen Huynh, H-H. Sherry Chow, Valerie D. Butler, Scott M. Lippman, Eva Szabo. M4OC-Prevent: Clinical evaluation of metformin for oral cancer precision prevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4985.

Pepsin: biomarker, mediator, and therapeutic target for reflux and aspiration

Extra-esophageal reflux is suspected to cause a wide range of clinical symptoms in the upper airways. Diagnosis and treatment has focused on acid, but realization of the role of nonacid reflux has resulted in research investigating the use of pepsin as a biomarker for gastric reflux and aspiration. Pepsin analysis can complement the use of questionnaires and office-based diagnosis and lessen the dependency on invasive and expensive diagnostic tests. Furthermore, pepsin as a first-line diagnostic biomarker has been shown to improve the accuracy of reflux diagnosis. In addition to its use as a diagnostic biomarker, pepsin has been shown to cause inflammation independent of the pH of the refluxate and thus despite acid suppression therapy. Research is ongoing to develop new therapies for airway reflux that specifically target pepsin.

Effects of talactoferrin alpha on lung adenoma prevention in A/J mice June 2, 2016

Talactoferrin alpha is a promising non-toxic solid tumor cancer agent that met with success in the treatment of early-stage lung cancer clinically in humans. It is well-tolerated, anddendritic cell-stimulation is a target. We tested the efficacy of this agent in a chemoprevention setting in A/J mice. All groups received benzo[a]pyrene (B[a]P) by oral gavage in three doses of 3 mg/kg body weight over the course of one week. Animals were then randomized into 5 groups of 24 mice per group based on weight. Experimental diets oftalactoferrin alpha (Agennix Inc., Indianapolis, IN), at 1.40% and 0.42% of the diet, were started one week or eight weeks after the last dose of B[a]P. Animals were continued on the feeding schedule, weighed weekly, and monitored for toxicity. The study was concluded 16 weeks after administration of B[a]P. The agent was well-tolerated for the duration of the experiment and there was no observable toxicity or weight change. The average number of adenomas per animal was 14.04 ± 0.93 (N=24) in the control group, 18.14 ± 1.45 (N=22) in the early low-dose group, 16.70 ± 1.30 (N=23) in the late low-dose group, 15.09 ± 1.41 (N=23) in the early high-dose group and 14.46 ± 1.21 (N=24) in the late high-dose group. We conclude talactoferrinalpha is well-tolerated. However, it did not inhibit carcinogenesis at a dose of 1.4% or 0.42% of the diet, which equates to human doses of 1.12 g/kg/day or 0.336 g/kg/day.

Thiazolidinediones abrogate cervical cancer growth

Peroxisome proliferator-activated receptor gamma (PPAR γ) is activated by thiazolidinedione drugs (TZDs) and can promote anti-cancer properties. We used three TZDs (pioglitazone, rosiglitazone, and ciglitazone) to target cervical cancer cell lines and a nude mouse animal model. Each agent increased activation of PPAR γ, as judged by a luciferase reporter gene assay in three HPV-associated cell lines (CaSki, SiHa, and HeLa cells) while decreasing cellular proliferation in a dose-dependent manner. They also promoted Oil Red O accumulation in treated cell lines and upregulated the lipid differentiation marker adipsin. Interestingly, xenograft HeLa tumors in nude mice treated with 100mg/kg/day pioglitazone exhibited decreased growth compared to control mice or mice treated with standard cervical chemotherapy. In conclusion, TZDs slow tumor cell growth in vitro and in vivo with decreases in cell proliferation and increases in PPAR γ and adipsin. These agents may be interesting treatments or treatment adjuncts for HPV-associated cancers or perhaps even precancerous conditions.

Fixed-Dose Combinations of Pioglitazone and Metformin for Lung Cancer Prevention

Combination treatment with pioglitazone and metformin is utilized clinically in the treatment of type II diabetes. Treatment with this drug combination reduced the development of aerodigestive cancers in this patient population. Our goal is to expand this treatment into clinical lung cancer chemoprevention. We hypothesized that dietary delivery of metformin/pioglitazone would prevent lung adenoma formation in A/J mice in a benzo[a]pyrene (B[a]P)-induced carcinogenesis model while modulating chemoprevention and anti-inflammatory biomarkers in residual adenomas. We found that metformin (500 and 850 mg/kg/d) and pioglitazone (15 mg/kg/d) produced statistically significant decreases in lung adenoma formation both as single-agent treatments and in combination, compared with untreated controls, after 15 weeks. Treatment with metformin alone and in combination with pioglitazone resulted in statistically significant decreases in lung adenoma formation at both early- and late-stage interventions. Pioglitazone alone resulted in significant decreases in adenoma formation only at early treatment intervention. We conclude that oral metformin is a viable chemopreventive treatment at doses ranging from 500 to 1,000 mg/kg/d. Pioglitazone at 15 mg/kg/d is a viable chemopreventive agent at early-stage interventions. Combination metformin and pioglitazone performed equal to metformin alone and better than pioglitazone at 15 mg/kg/d. Because the drugs are already FDA-approved, rapid movement to human clinical studies is possible. Cancer Prev Res; 10(2); 116-23. ©2017 AACR.

Safety and Preclinical Efficacy of Aerosol Pioglitazone on Lung Adenoma Prevention in A/J Mice

Pioglitazone is a PPARγ agonist commonly prescribed for the clinical treatment of diabetes. We sought to expand its use to lung cancer prevention in a benzo[a]pyrene (B[a]P) mouse model with direct lung delivery via inhalation. Initially, we conducted inhalational toxicity experiments with 0, 15, 50, 150, and 450 μg/kg body weight/day pioglitazone in 40 A/J mice. We examined the animals for any physical toxicity and bronchoalveolar lavage fluids for inflammatory and cytotoxicity markers. Doses up to and including 450 μg/kg bw/d failed to demonstrate toxicity with aerosol pioglitazone. For chemoprevention experiments, A/J mice were randomized to treatment groups of inhaled doses of 0, 50, 150, or 450 μg/kg bw/d pioglitazone 1 or 8 weeks after the last dose of B[a]P. For the early treatment group, we found up to 32% decrease in lung adenoma formation with 450 μg/kg bw/d pioglitazone. We repeated the treatments in a second late-stage experiment and found up to 44% decreases in lung adenoma formation in doses of pioglitazone of 150 and 450 μg/kg bw/day. Both the early- and the late-stage experiments demonstrated biologically relevant and statistically significant decreases in adenoma formation. We conclude that aerosol pioglitazone is well-tolerated in the A/J mouse model and a promising chemoprevention agent for the lower respiratory tract. Cancer Prev Res; 10(2); 124-32. ©2016 AACR.

Correlation analysis of oral lesion sizes by various standardized criteria

OBJECTIVE

Requirements of an NCI contract examining a novel treatment for leukoplakia were to compare standard bi-dimensional measurement of oral lesions to examine for correlation with Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and to examine the feasibility of digital image analysis for automated measurements.

STUDY DESIGN

Retrospective review.

METHODS

We examined 13 patients by bi-dimensional measurement and compared these measurements to 1) RECIST criteria, 2) scalar digital measurements using a standardized measuring device within the photograph, and 3) pixel number.

RESULTS

RECIST criteria correlated (r-squared=0.8535, p<0.0001) with bi-dimensional measurements. Digitized measures in photographs correlated with bi-dimensional measurements (r-squared=0.6661, p=0.0007), but were time consuming. There was minimal to no correlation between pixel number in Adobe Photoshop and the other measures.

CONCLUSION

Bi-dimensional measurement of oral leukoplakia and RECIST criteria are highly correlated. Digital photography measurements, though highly correlative, are very cumbersome. We recommend bi-dimensional or longest length measurement and a simple photograph as standard of documentation for leukoplakia lesions.

Abstract 2611: Effects of chalcones, nicotinamide, and resveratrol on PPAR gamma activation in oral cancer cells

Several classes of natural products have cancer prevention potential and PPAR gamma is an intriguing chemoprevention target as a nuclear receptor that controls multiple growth and differentiation processes. We have previously tested many classes of natural products in A/J mice and have found that the following chemoprevention compounds had no significant dietary toxicities: inositol, eucalyptol, chalcones, nicotinamides, and resveratrol. We tested these compounds for their capacity to activate PPAR gamma reporter genes in CA-9-22 oral cancer cells. In several repeated experiments we found that Inositol hexaphosphate did not activate PPAR gamma reporter genes at high concentrations of 1-4 mM. We found that eucalyptol, trans-Chalcone, 4 methoxy chalcone, Nicotinic Acid, and Nicotinamide had the capacity for statistically significant activation of PPAR gamma reporter genes in oral cancer cells from 20-60% at concentrations of 1-100 uM. We found that resveratrol was the most potent agent and could activate PPAR gamma reporter genes 2 fold. As a reference, this was about half the activity of the prototypic PPAR gamma activator pioglitazone. We performed additional experiments with resveratrol and found that it could activate the PPAR gamma dependent squamous differentiation gene Involucrin in oral cancer cells and BEAS 2B cells. Additionally, resveratrol significantly decreased BEAS 2 B proliferation from 48-96 hours at concentrations of 10 uM. From this data we conclude that resveratrol has the capacity to activate PPAR gamma in vitro and resveratrol and its derivatives may also function as PPAR gamma activators as an additional mechanism of action. We also conclude that inositol, eucalyptol, chalcones, and nicotinamides do not activate PPAR gamma.

Citation Format: Jennifer Diaz, Beverly Wuertz, Art Galbraith, Frank G. Ondrey. Effects of chalcones, nicotinamide, and resveratrol on PPAR gamma activation in oral cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2611.

Induction of Heat Shock Protein 70 Inhibits NF-kappa-B in Squamous Cell Carcinoma

OBJECTIVE: To determine the relationship between heat shock proteins (HSPs) and the proinflammatory, anti-apoptosis mediator NF-kappa-B in squamous cell carcinoma.

STUDY DESIGN AND SETTING: CA-9-22 cells were exposed to heat stress to induce the production of HSPs. Immunoblot and reporter gene experiments determined the inducibility of HSP production and the activation of cytokine-induced NF-kappa-B. Immunoblot experiments determined the presence of the inhibitor- k-B-α (I kBα).

RESULTS: CA-9-22 cells can be induced by heat stress to produce HSPs at 100-fold above baseline levels. The induction of HSPs prevents the activation and nuclear translocation of NF-kappa-B despite stimulation with IL-1β and TNF-α.

CONCLUSIONS: Constitutive activation of NF-kappa-B is prevented by HSP induction through an increase in I kBα synthesis.

SIGNIFICANCE: The induction of HSP70 alters the inflammatory milieu associated with squamous cell carcinoma progression through the inhibition of NF-kappa-B and may ultimately promote apoptosis in head and neck carcinoma.

PPAR Activation and Decreased Proliferation in Oral Carcinoma Cells With 4-HPR

OBJECTIVE: To explore whether the mechanism of action of 4-hydroxyphenylretinamide (4-HPR, fenretidine), a synthetic retinoid, involves the functional activation of the nuclear hormone receptor class known as PPARs (peroxisome proliferator-activated receptors). Also, to examine whether anti-proliferative effects of this agent in head and neck cancer cells occur at biologically relevant concentrations.

STUDY DESIGN/METHODS: CA 9–22, NA, and UM SCC 11B cells were treated with 4-HPR during their log phase growth and functional activation of PPAR γ was evaluated by plate luminometry. Cellular proliferation was analyzed by standard MTT cell proliferation assays and cell counting. Student's t tests were performed for all experiments.

RESULTS: Significant dose-dependent increases in PPAR γ activation occurred in response to 4-HPR treatment. Proliferation was significantly inhibited by 4-HPR in a dose-dependent manner as judged by MTT and cell counting assays. These effects occurred at equimolar concentrations in both types of experiments within a range of clinically achievable doses (1–4 μM) of 4-HPR.

CONCLUSIONS: 4-HPR can functionally activate PPAR γ at clinically achievable doses. Decreased cancer cell proliferation secondary to PPAR γ activation has been observed in other malignancies as well as upper aerodigestive cancer. PPAR γ activation by 4-HPR represents another potential anti-cancer mechanism of action for this drug.

CLINICAL SIGNIFICANCE: PPAR γ activation represents a novel target for anti-cancer therapy for head and neck cancer and the current level of clinical toxicity of 4-HPR would be judged acceptable to utilize this agent alone or in combination chemotherapy.

Functional activation of PPARγ in human upper aerodigestive cancer cell lines

Upper aerodigestive cancer is an aggressive malignancy with relatively stagnant long-term survival rates over 20 yr. Recent studies have demonstrated that exploitation of PPARγ pathways may be a novel therapy for cancer and its prevention. We tested whether PPARγ is expressed and inducible in aerodigestive carcinoma cells and whether it is present in human upper aerodigestive tumors. Human oral cancer CA-9-22 and NA cell lines were treated with the PPAR activators eicosatetraynoic acid (ETYA), 15-deoxy-δ- 12,14-prostaglandin J2 (PG-J2), and the thiazolidinedione, ciglitazone, and evaluated for their ability to functionally activate PPARγ luciferase reporter gene constructs. Cellular proliferation and clonogenic potential after PPARγ ligand treatment were also evaluated. Aerodigestive cancer specimens and normal tissues were evaluated for PPARγ expression on gene expression profiling and immunoblotting. Functional activation of PPARγ reporter gene constructs and increases in PPARγ protein were confirmed in the nuclear compartment after PPARγ ligand treatment. Significant decreases in cell proliferation and clonogenic potential resulted from treatment. Lipid accumulation was induced by PPARγ activator treatment. 75% of tumor specimens and 100% of normal control tissues expressed PPARγ RNA, and PPARγ protein was confirmed in 66% of tumor specimens analyzed by immunoblotting. We conclude PPARγ can be functionally activated in upper aerodigestive cancer and that its activation downregulates several features of the neoplastic phenotype. PPARγ expression in human upper aerodigestive tract tumors and normal cells potentially legitimizes it as a novel intervention target in this disease. © 2016 Wiley Periodicals, Inc.

Abstract LB-264: Effects of dietary metformin/pioglitazone on lung adenoma formation in A/J mice

Introduction: Metabolomics and cancer chemoprevention are important contemporary concepts in cancer prevention and gaining traction as potential clinical trial topics. Our group has worked with type II diabetes agents clinically in oral cancer prevention and clinically and preclinically in both lung and head and neck cancer. Both pioglitazone and metformin are type II diabetes agents, and both drugs have promising epidemiologic evidence for efficacy as solid tumor prevention agents. They are well tolerated clinically for many years in millions of patients worldwide with acceptable toxicity profiles. We hypothesize these agents would be suitable in the chemoprevention setting and tested this hypothesis in experimental lung carcinogenesis in a benzo[a]pyrene (B[a]P) mouse model.

Materials and Methods: We utilized 224 seven week old female A/J mice. All groups received 3 weekly doses of B[a]P by oral intubation and were randomized into 8 groups of 27 mice per group based on weights. Experimental diets were started one week after the last dose of B[a]P. Metformin (12 mg/g and 10.2 mg/g) and/or pioglitazone (0.18mg/g) were administered in the diet for 18 weeks, whereas late stage inhibition diets were started at 8 weeks post carcinogen. Animals were continued on the feeding schedule, weighed weekly, and monitored for weight loss, behavior changes, rough hair coat, or other signs of ill health.

Results: The average number of adenomas per animal was 17.44 +/- 1.39 (SEM) in the control group. At the early stage intervention the average number of adenomas was 5.00 +/- 0.69 (P&lt;0.0001) in the highest dose of metformin, 6.15 +/- 0.57 (P&lt;0.0001) for the low dose metformin, and 11.92 +/-1.00 (P = 0.0023) for pioglitazone treatment. Metformin (low dose) and pioglitazone in combination resulted in 5.26 +/- 0.78 (P&lt;0.0001) adenomas per animal. At the late stage intervention the average number of adenomas was 10.89 +/- 1.161 (P = 0.0007) for the low dose metformin, and 14.42 +/-1.24 (P = 0.1126, not significant) for pioglitazone treatment. Metformin (low dose) and pioglitazone in combination resulted in 9.77 +/- 0.85 (P&lt;0.0001) adenomas per animal. The agents were well tolerated for the duration of the experiment from all physical appearance and other standard toxicities. However, animals treated with metformin had a 15% weight loss at the beginning of the experiment and completed the experiment with body weights 15% lower compared to non-metformin treated animals.

Conclusions: We conclude metformin and pioglitazone are promising agents for lung adenoma prevention in A/J mice. We also conclude dose adjustments of these drugs may require further optimization. Drugs of the thiazolidinedione class and sulfonylureas are powerful controllers of glucose metabolism. Although we did not have observable toxicity in the animals, it is likely glucose metabolism was altered and this contributed to the 15% differences in weight between the animal groups. Therefore, well designed metabolomic studies may be helpful in the future.

Citation Format: Donna Seabloom, Art Galbraith, Beverly Wuertz, Anna Haynes, Mark S. Miller, Vernon Steele, Lee Wattenberg, Frank G. Ondrey. Effects of dietary metformin/pioglitazone on lung adenoma formation in A/J mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-264. doi:10.1158/1538-7445.AM2015-LB-264

Abstract 914: Pioglitazone and metformin as potential chemopreventative treatments in Fanconi anemia related oral squamous carcinoma

Fanconi anemia (FA) is a genetic disorder which leads to bone marrow failure and cancer due to mutations in DNA repair mechanisms. FA is also a solid tumor-prone disease, affecting patients decades earlier and at a rate several hundred-fold higher than the general population necessitating regular cancer surveillance. To better understand the features of post-BMT oral SCC tumors and assist in development of preventative, survival-enhancing therapies for FA patients, we established a cell line and treated it with a panel of emerging chemopreventatives and natural compounds. An adjunct therapy with a minimal side effect profile will help this population in which chemotherapy and radiation are particularly damaging.

We established a cell line from a post bone marrow transplant FA patient with a T2N2bM0 oral SCC grown as an adherent monolayer culture. The chemopreventative compound panel we used included Pioglitazone and Metformin. We also tested the synthetic retinoid Bexarotene, and commonly used chemotherapeutics Taxol and Cisplatin. MTT assays determined cell viability after 1, 2, and 3 days of treatment. Clonogenic assays were performed to determine survival and proliferation over 1-2 weeks. Reporter gene assays were performed to determine the effect of treatments on several target genes, to investigate pathway response and potential candidate biomarkers.

Our results show Pioglitazone at all concentrations (5, 10, 20, 40μM) decreases cell proliferation compared to solvent controls (P&lt;0.0001). Metformin (1 - 100μM) unexpectedly increased cell proliferation or was otherwise equal in growth with the controls, with the exception of the high dose (10mM) which decreased cell proliferation (P&lt;0.0001). Taxol, Cisplatin, and Bexarotene were also found to decrease cell proliferation in a dose-dependent manner. Clonogenic assays demonstrated dose-dependent decreases in colony forming ability with Pioglitazone and Bexarotene, however no significant changes were shown with Metformin treatments. Reporter gene assays revealed that PPAR ligand binding activity was upregulated in FA cells treated with Pioglitazone (P&lt;0.02 at 40μM, P = 0.0003 at 10μM) compared to controls. Conversely PPAR activity was decreased compared to controls in FA cells treated with Metformin (P&lt;0.0001 for all concentrations of Metformin) and Bexarotene (P&lt;0.0001 for all concentrations of Bexarotene 1, 2, 4μM).

Pioglitazone seems to be a promising chemopreventative adjunct treatment for HNSCC in FA patients. Further studies are underway to evaluate the contribution of decreased cell proliferation versus apoptotic mechanisms. Metformin does not appear to decrease tumor cell proliferation at doses up to 100 uM in our FA cell line.

Citation Format: Kim Miller, Beverly Wuertz, Frank G. Ondrey. Pioglitazone and metformin as potential chemopreventative treatments in Fanconi anemia related oral squamous carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 914. doi:10.1158/1538-7445.AM2015-914

Abstract 2174: Association of diabetes and obesity with risk of esophageal and gastric adenocarcinoma in the Iowa Women's Health Study (IWHS)

Incidence rates of esophageal and gastric cancers have increased rapidly in developing countries during the past four decades. The rate of esophageal adenocarcinomas has approximately tripled among US whites and now exceeds that of esophageal squamous cell carcinomas. Incidence of gastric cardia adenocarcinomas has also risen significantly during this period, though to a lesser extent. These cancers often respond poorly to treatment, highlighting the importance of identifying modifiable risk factors with a view to prevention. The association between diabetes and gastroesophageal adenocarcinoma has been examined in only a few studies and findings are inconsistent. While obesity is a significant risk factor for esophageal and gastric adenocarcinomas, few analyses have been conducted in prospective cohorts. We examined the association between diabetes, BMI, and waist circumference and incidence of esophageal, non-cardia gastric and gastric cardia adenocarcinomas in a large prospective cohort of postmenopausal women. A mailed survey at baseline (1986) collected information on self-reported diabetes and anthropometric measures and included a detailed food-frequency questionnaire. The 34,466 initially cancer free women were followed for 24 years with annual cancer incidence obtained through the State Health Registry of Iowa, part of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program; 83 women developed gastroesophageal adenocarcinoma. Associations were examined using proportional hazards regression models: hazard ratios (HR) and 95% confidence intervals (CI) were calculated. Significant associations were observed in age-adjusted models for diabetes (yes/no) [HR: 2.09, 95% CI: 1.01-4.34], body mass index (kg per meters squared) [HR: 1.09, 95% CI: 1.03-1.15], and waist circumference (cm) [HR: 1.24, 95% CI: 1.01-1.53]. Additionally, a positive association between diabetes and adenocarcinoma of the gastroesophageal junction was found in both age-adjusted [HR: 3.43, 95% CI: 1.32-8.90] and multivariate-adjusted models [HR: 3.00, 95% CI: 1.13-7.99]. An inverse association was found with increasing daily fiber intake (g/day) and all gastroesophageal adenocarcinomas [HR: 0.84, 95% CI: 0.73-0.96]. These findings support the view that diabetes, body mass index and waist circumference increase risk of gastroesophageal adenocarcinoma while increased fiber intake may decrease risk.

Citation Format: Bryan P. LaBore, Anna E. Prizment, Frank G. Ondrey, Kristin E. Anderson. Association of diabetes and obesity with risk of esophageal and gastric adenocarcinoma in the Iowa Women's Health Study (IWHS). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2174. doi:10.1158/1538-7445.AM2014-2174

Abstract 2140: Efficacy of aerosolized pioglitazone in lung carcinogenesis in A/J mice

Pioglitazone is a PPAR gamma agonist commonly utilized clinically in the treatment of diabetes. There have been clinical trials with this agent in oral cancer prevention and we sought to potentially expand its use in lung cancer in a B[a]P mouse model. Directed epithelial delivery in lung cancer is an attractive treatment approach and we felt pioglitazone would be amenable to aerosol delivery. Initially, a maximum tolerated dose experiment examining standard toxicity parameters, including animal behavior characteristics, weight, general health, and increases in markers of cytotoxicity in bronchoalveolar lavage was conducted. We found no statistically significant indications of increased toxicity in the animals with administration of aerosolized pioglitazone and proceeded with the prevention protocol. We utilized 192 seven week old female A/J mice. All groups received Benzo[a]pyrene by oral gavage in 3 doses of 3mg/kg body weight over the course of 1 week. Animals were then randomized into 8 groups of 24 mice per group based on weight. Experimental diets, 0, 50, 150, and 450µg/kg body weight pioglitazone formulated into 0.6µm average diameter respiratory particles, were started 1 week or 8 weeks after last dose of B[a]P. Animals were continued on the feeding schedule, weighed weekly, and monitored for weight loss, attenuation, rough hair coat, or other signs of ill health. The study was concluded 16 weeks after administration of B[a]P. The agent was well tolerated for the duration of the experiment and there was no observable toxicity. The average number of adenomas per animal in the late treatment group was 10.69 ± 1.685 in the control, 12.27 ± 1.761 in the 50µg, 6.000 ± 0.6359 in the 150 µg, and 7.267 ± 1.071 in the 450µg groups but low control tumor counts in the early treatment group precluded analysis. The same tumor initation protocol was used with 72 mice. Animals were randomized into 3 groups of 24 animals and treated with 0, 150, or 450µg/kg body weight aerosol pioglitazone for 16 weeks starting 1 week after the last B[a]P dose. The average number of adenomas per animal was 9.217 ± 1.004 in the control, 7.957 ± 0.9440 in the in the 150 µg, and 6.304 ± 0.8653 in the 450µg groups. We conclude aerosol pioglitazone is well tolerated in the A/J mouse model and a promising chemoprevention agent in the aerodigestive tract.

Citation Format: Donna Seabloom, Art Galbraith, Beverly Wuertz, Anna Haynes, Jenny Antonides, alisha fujita, Vernon Steele, Lee Wattenberg, Frank G. Ondrey. Efficacy of aerosolized pioglitazone in lung carcinogenesis in A/J mice. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2140. doi:10.1158/1538-7445.AM2014-2140

Mechanism and efficacy of sub-50-nm tenfibgen nanocapsules for cancer cell-directed delivery of anti-CK2 RNAi to primary and metastatic squamous cell carcinoma

Improved survival for patients with head and neck cancers (HNC) with recurrent and metastatic disease warrants that cancer therapy is specific, with protected delivery of the therapeutic agent to primary and metastatic cancer cells. A further objective should be that downregulation of the intracellular therapy target leads to cell death without compensation by an alternate pathway. To address these goals, we report the utilization of a sub-50-nm tenfibgen (s50-TBG) nanocapsule that delivers RNAi oligonucleotides directed against the essential survival signal protein kinase CK2 (RNAi-CK2) in a cancer cell-specific manner. We have evaluated mechanism and efficacy of using s50-TBG-RNAi-CK2 nanocapsules for therapy of primary and metastatic head and neck squamous cell carcinoma (HNSCC). s50-TBG nanocapsules enter cancer cells via the lipid raft/caveolar pathway and deliver their cargo (RNAi-CK2) preferentially to malignant but not normal tissues in mice. Our data suggest that RNAi-CK2, a unique single-stranded oligonucleotide, co-opts the argonaute 2/RNA-induced silencing complex pathway to target the CK2αα' mRNAs. s50-TBG-RNAi-CK2 inhibited cell growth corresponding with reduced CK2 expression in targeted tumor cells. Treatment of three xenograft HNSCC models showed that primary tumors and metastases responded to s50-TBG-RNAi-CK2 therapy, with tumor shrinkage and 6-month host survival that was achieved at relatively low doses of the therapeutic agent without any adverse toxic effect in normal tissues in the mice. We suggest that our nanocapsule technology and anti-CK2 targeting combine into a therapeutic modality with a potential of significant translational promise.

Quantitative proteomic analysis of oral brush biopsies identifies secretory leukocyte protease inhibitor as a promising, mechanism-based oral cancer biomarker

A decrease in the almost fifty percent mortality rate from oral cancer is needed urgently. Improvements in early diagnosis and more effective preventive treatments could affect such a decrease. Towards this end, we undertook for the first time an in-depth mass spectrometry-based quantitative shotgun proteomics study of non-invasively collected oral brush biopsies. Proteins isolated from brush biopsies from healthy normal tissue, oral premalignant lesion tissue (OPMLs), oral squamous cell carcinoma (OSCC) and matched control tissue were compared. In replicated proteomic datasets, the secretory leukocyte protease inhibitor (SLPI) protein stood out based on its decrease in abundance in both OPML and OSCC lesion tissues compared to healthy normal tissue. Western blotting in additional brushed biopsy samples confirmed a trend of gradual decreasing SLPI abundance between healthy normal and OPML tissue, with a larger decrease in OSCC lesion tissue. A similar SLPI decrease was observed in-vitro comparing model OPML and OSCC cell lines. In addition, exfoliated oral cells in patients’ whole saliva showed a loss of SLPI correlated with oral cancer progression. These results, combined with proteomics data indicating a decrease in SLPI in matched healthy control tissue from OSCC patients compared to tissue from healthy normal tissue, suggested a systemic decrease of SLPI in oral cells correlated with oral cancer development. Finally, in-vitro experiments showed that treatment with SLPI significantly decreased NF-kB activity in an OPML cell line. The findings indicate anti-inflammatory activity in OPML, supporting a mechanistic role of SLPI in OSCC progression and suggesting its potential for preventative treatment of at-risk oral lesions. Collectively, our results show for the first time the potential for SLPI as a mechanism-based, non-invasive biomarker of oral cancer progression with potential in preventive treatment.

Not significant but important

Armstrong and colleagues report the result of a large Phase IIb randomized trial evaluating the effectiveness of a preparation of the Bowman Birk Inhibitor compared with an oral placebo in reversing the extent of oral leukoplakia as measured visually by pathology or a battery of intermediate end points. In this editorial, we review the report of this negative clinical trials result to highlight the clinical trial process used in evaluating this previously promising chemoprevention agent. Publishing this report is important to address concerns with publication bias. The challenges in running a chemoprevention trial are reviewed with suggestions to enhance progress going forward. Conceptually, developing drugs to intercept the early stages of carcinogenesis is very attractive, but progress in this area has been slow. Two opportunities to overcome this reality are discussed. These measures include the broader use of neoadjuvant, window-of-opportunity trials with new candidate chemoprevention agents to get more textured information about the mechanistic impact of the drug exposure in previously untreated early tumor tissue. In addition, we discuss the use of new intermediate end point markers such as with optical imaging tools to obtain a more objective and quantitative assessment of drug response.

Abstract 4865: Lack of efficacy of aerosolized resveratrol on B[A]P induced pulmonary adenoma formation in A/J mice

Natural products constitute an emerging class of compounds for carcinogenesis prevention in a variety of solid tumor malignancies. Resveratrol is a compound that has outstanding efficacy on cancer prevention in in vitro carcinogenesis models but rapid solubility and metabolism limits its efficacy in animal models when delivered in the diet. However, if regional or topical delivery could be achieved effects of first pass metabolism might be avoided. In the present study, we sought to use aerosol resveratrol to examine whether it could inhibit Benzpyrene inducd pulmonary adenoma formation in A/J mice. Eight groups of 24 mice were given Benzpyrene and aerosol resveratrol was started either one week or 8 weeks after the conclusion of the Benzpyrene. Aerosolized resveratrol (1.0, 0.3, and 0.1 mg/kg) was delivered 5x per week Monday through Friday for weeks 2- 15. At the conclusion of the experiment animals were sacrificed and adenomas counted. We found that the animals tolerated the aerosol resveratrol without toxicity and without weight differences between all groups. Animals formed between 9 and 12 adenomas, on average throughout all groups. There were no effects of aerosol resveratrol on either early stage or late stage carcinogenesis, nor were there any trends between the groups. We conclude that the high water solubility of resveratrol likely allowed for its rapid transit and metabolism through the bronchioles and lung parenchyma and that possibly chemical modifications of resveratrol that allow for its deposition in the lung fields in a way to increase its residence time would allow for better efficacy.

Citation Format: Donna Seabloom, Art Gailbraith, Jenny Antonides, Beverly Wuertz, Lee Wattenberg, Frank G. Ondrey. Lack of efficacy of aerosolized resveratrol on B[A]P induced pulmonary adenoma formation in A/J mice. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4865. doi:10.1158/1538-7445.AM2013-4865

Id2 regulates the proliferation of squamous cell carcinoma in vitro via the NF-κB/Cyclin D1 pathway

Squamous cell carcinoma (SCC) is a significant cause of cancer morbidity and mortality worldwide, with an incidence of up to 166 cases per 100 000 population. It arises in the skin, upper aerodigestive tract, lung, and cervix and affects more than 200 000 Americans each year. We report here that a microarray experiment comparing 41 SCC and 13 normal tissue specimens showed that Id2, a gene that controls the cell cycle, was significantly up-regulated in SCC. Enforced expression of Id2 in vitro stimulated the proliferation of SCC cells and up-regulated the transcription of nuclear factor kappa B (NF-κB) and cyclin D1. Enhancement of the NF-κB activity with p65 significantly increased the cell proliferation and the transcription of cyclin D1, whereas inhibition of the NF-κB activity with I kappa B alpha mutant (IκBα M) and pyrroline dithiocarbamate (PDTC) abrogated cell proliferation and transcription of cyclin D1. Furthermore, a mutated NF-κB binding site in the cyclin D1 promoter fully abrogated the Id2-induced transcription of cyclin D1. Taken together, these data indicate that Id2 induces SCC tumor growth and proliferation through the NF-κB/cyclin D1 pathway.

DeCIDE: A phase III randomized trial of docetaxel (D), cisplatin (P), 5-fluorouracil (F) (TPF) induction chemotherapy (IC) in patients with N2/N3 locally advanced squamous cell carcinoma of the head and neck (SCCHN)

5500

Background: IC is associated with lower distant failure (DF) rates in SCCHN but an improvement in overall survival (OS) has not been validated. The goal of this trial was to determine whether IC prior to chemoradiotherapy (CRT) improves survival compared to CRT alone. Methods: In this phase 3, open-label trial, subjects with pathologically confirmed SCCHN; N2/N3 disease without metastases; no prior therapy; KPS ³ 70%; and intact organ function were randomized to CRT alone (CRT arm) [5 days of D (25 mg/m2), F (600 mg/m2), hydroxyurea (500 mg BID), and RT (150 cGy BID) followed by a 9 day break] or to 2 cycles of IC [D (75 mg/m2), P (75 mg/m2), F (750 mg/m2 day 1-5)] followed by the same CRT (IC arm). Primary endpoint was OS. Secondary endpoints included DF free survival, failure pattern, and recurrence-free survival (RFS). 280 subjects provided 80% power to detect a hazard ratio HR=0.5 for OS (a=0.05). Results: 280 subjects were accrued from 2004-09 with minimum follow-up 24 months. Of 142 patients randomized to IC, 91% received 2 cycles and 87% continued to CRT. Treatment adherence during CRT was high for docetaxel and hydroxyurea, but fewer than 75% of the patients received target dose of 5FU in both arms. RT was delivered without major deviations in 94% and 95% of patients on IC and CRT arms, respectively. The most common grade 3-4 toxicities during IC were febrile neutropenia (9%) and mucositis (8%), and during CRT (both arms combined) they were mucositis (45%), dermatitis (19%), and leukopenia (17%). Only grade 3-4 leukopenia and neutropenia rates were significantly higher in IC (p=0.002 and p=0.02, respectively). Table shows efficacy. Conclusions: High survival rates were observed in both arms. Further analysis and follow-up may provide insight into why the significant decrease in DF did not translate into improved OS. [Table: see text]

A comparison of screening methods in two early phase oral leukoplakia clinical trials

OBJECTIVES/INTRODUCTION

Clinical trial accrual for oral dysplasia is difficult in the United States and elsewhere. Patients with dysplastic oral leukoplakia progress to frank invasive carcinoma at a rate of 5-37% over 5 years. We compared two clinical trial screening efforts to hopefully devise better accrual strategies to these types of clinical trials.

METHODS

For the first trial, we identified 244 patients with dysplastic oral leukoplakia in our university database and a media campaign. Patients were notified and screened by examination and biopsy. For the second clinical trial, we established a preneoplastic lesions clinic and teaching and communications network with regional oral healthcare professionals.

RESULTS

Only one of 244 patients accrued to the first clinical trial through an organized screening effort based on database/medical records review. The second clinical trial accrued 16/30 screened patients through redirected efforts in teaching, communications, and a preneoplastic lesions clinic.

CONCLUSION

We conclude that significant difficulties resulted from medical record/database review of leukoplakia patients as a screening method for leukoplakia clinical trial entry. We feel that persistent direct contact and education of healthcare professionals who are likely to examine leukoplakia patients improved accrual to the second clinical trial.

Abstract 601: PPARδ mediated p21 induction in aerodigestive preneoplastic cell lines

PPARδ activating strategies are currently being tested preclinically and clinically in aerodigestive cancer prevention. Thiazolidinedione drugs like pioglitazone are clinically used for the treatment of diabetes and activate PPARδ as a primary target. P21/WAF1 is a cell cycle protein that is a cyclin dependent kinase inhibitor that reguylates cell cycle progression at the G1 phase; therefore its induction may be associated with cell cycle downregulation in precancerous cells experiencing increased proliferation. In our present study we examined the effects of pioglitazone on proliferation in human leukoplakia cells (MSK 1) and transformed lung (BEAS 2B) cells. We found that pioglitazone significantly inhibited cell proliferation in both cell lines in a dose dependent fashion at concentrations between 0 and 40 uM, as judged by MTT assays from 1-5 days. We found p21/WAF 1 induction by western blot within the first eight hours after the intitiation of treatment with pioglitazone, which were preceded by measureable increases in p21 induction on q PCR. In an analysis of an Affymetrix database of human head and neck tumors (41 tumors compared to 13 normal oral mucosa samples), we found significant dysregulation in several p21 activated kinases. We conclude the PPARδ activator, pioglitazone, can activate p21, which is associated with decreased proliferation in 2 aerodigestive preneoplastic cell lines. We also conclude that this gene may be a potential hypothesis driven biomarker in translational studies of pioglitazone as a chemoprevention agent for aerodigestive cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 601. doi:1538-7445.AM2012-601

The effect of indomethacin on paclitaxel sensitivity and apoptosis in oral squamous carcinoma cells: the role of nuclear factor-κB inhibition

OBJECTIVE

To investigate new strategies to intensify chemosensitivity in head and neck squamous cell carcinoma.

DESIGN

Oral squamous carcinoma cells were examined for nuclear factor-κB (NF-κB) activation and binding activity by paclitaxel, an agent currently used in head and neck cancer chemotherapy. Electromobility shift assays were used to assess the effect of indomethacin on NF-κB binding activity. Cell proliferation assays were used to study cell sensitivity to paclitaxel. To examine whether cytotoxicity could be increased by specifically inhibiting NF-κB, a dominant negative cell line, inhibitor kappa B-alpha (IκBα), was stably expressed in CA-9-22 cells.

RESULTS

Paclitaxel possessed the capacity to functionally activate NF-κB, as demonstrated by luciferase reporter gene assays and electromobility shift assay. Indomethacin was able to inhibit paclitaxel-mediated NF-κB activation and promote apoptosis of paclitaxel-treated cells at 24 hours. Indomethacin augmented the paclitaxel cell-killing effect. The dominant negative IκBα cell line exhibited increased chemosensitization to paclitaxel by 2- to 10-fold.

CONCLUSIONS

Paclitaxel has the capacity to activate NF-κB in oral squamous carcinoma cells. Indomethacin can reverse this activation to decrease cell proliferation and increase apoptosis. Treatment strategies that combine paclitaxel with indomethacin may have therapeutic benefits attributable to paclitaxel chemosensitization through NF-κB inhibition.

Tobacco carcinogen mediated up-regulation of AP-1 dependent pro-angiogenic cytokines in head and neck carcinogenesis

Tobacco is notably genotoxic and associated with head and neck carcinogenesis. Cigarette carcinogens have the capacity to alter early response gene expression in tobacco-related malignancies via genes such as nuclear factor kappa B (NFκB). A number of early response gene activation events are also facilitated by fos/jun activator protein 1 (AP-1) associated pathways. In the present study, we hypothesize that tobacco products may induce microenvironment alterations, promoting angiogenesis and providing a permissive environment for head and neck cancer progression. In an in vitro analysis, we employed immortalized oral keratinocyte (HOK-16B) and laryngeal squamous carcinoma (UM-SCC-11A) cells to investigate interleukin (IL)-8 and vascular endothelial growth factor (VEGF) induction by cigarette smoke condensate (CSC). IL-8 and VEGF expression is based on interactions between NFκB, AP-1, and NF-IL6. We identified at least 1.5-fold dose-dependent induction of AP-1, VEGF, and IL-8 promoter/reporter gene activity after 24 h exposure to CSC. Next, we stably transfected UM-SCC-11A cells with A-Fos, a dominant negative AP-1 protein. Treatment with CSC of the A-Fos cell lines compared to empty vector controls significantly down-regulated AP-1, VEGF, and IL-8 promoter/reporter gene expression. We also performed ELISAs and discovered significant up-regulation of IL-8 and VEGF secretion by UMSCC 11A after treatment with phorbol 12-myristate 13-acetate, tumor necrosis factor alpha, and CSC, which was down-regulated by the A-Fos dominant negative protein. We conclude tobacco carcinogens up-regulate AP-1 activity and AP-1 dependent IL-8 and VEGF gene expression in head and neck cancer. This up-regulation may promote an angiogenic phenotype favoring invasion in both premalignant and squamous cancer cells of the head and neck.