Faculty Bibliography

The TLR7/8 agonist, Resiquimod has been used as an immune adjuvant in cancer vaccines. We evaluated the safety and immunogenicity of the cancer testis antigen NY-ESO-1 given in combination with Montanide with or without Resiquimod in high risk melanoma patients. In Part I of the study, patients received 100ug full length NY-ESO-1 protein emulsified in 1.25mL Montanide (day 1) followed by topical application of 1000mg of 0.2% Resiquimod gel on days 1 and 3 (Cohort 1) versus days 1, 3, and 5 (Cohort 2) of a 21 day cycle. In Part II, patients were randomized to receive 100ug NY-ESO-1 protein plus Montanide (day 1) followed by topical application of placebo gel (Arm-A; N=8) or 1000mg of 0.2% Resiquimod gel (Arm-B; N=12) using the dosing regimen established in Part I. The vaccine regimens were generally well-tolerated. NY-ESO-1 specific humoral responses were induced or boosted in all patients, many with high titers. In Part II, 16 of 20 patients in both arms had NY-ESO-1-specific CD4+ T cell responses. CD8+ T cell responses were only seen in 3 of 12 patients in Arm B. Patients with TLR7 SNP rs179008 had a greater likelihood of developing NY-ESO-1-specific CD8+ responses. In conclusion, NY-ESO-1 protein in combination with Montanide with or without topical Resiquimod is safe and induces both antibody and CD4+ cell responses in the majority of patients; the small proportion of CD8+ cell responses suggests that the addition of topical Resiquimod to Montanide is not sufficient to induce consistent NY-ESO-1 specific CD8+ cell responses.

BACKGROUND: Surgical management of primary melanoma is curative for most patients with clinically localized disease at diagnosis; however, a substantial number of patients recur and progress to advanced disease. Understanding molecular alterations that influence differential tumor progression of histopathologically similar lesions may lead to improved prognosis and therapies to slow or prevent metastasis. METHODS: We examined microRNA dysregulation by expression profiling of primary melanoma tumors from 92 patients. We screened candidate microRNAs selected by differential expression between recurrent and nonrecurrent tumors or associated with primary tumor thickness (Student's t test, Benjamini-Hochberg False Discovery Rate [FDR] < 0.05), in in vitro invasion assays. We performed in vivo metastasis assays, matrix remodeling experiments, and molecular studies to identify metastasis-regulating microRNAs and their cellular and molecular mechanisms. All statistical tests were two-sided. RESULTS: We identified two microRNAs (hsa-miR-382, hsa-miR-516b) whose expression was lower in aggressive vs nonaggressive primary tumors, which suppressed invasion in vitro and metastasis in vivo (mean metastatic foci: control: 37.9, 95% confidence interval [CI] = 25.6 to 50.2; miR-382: 19.5, 95% CI = 12.2 to 26.9, P = .009; miR-516b: 12.5, 95% CI = 7.7 to 17.4, P < .001, Student's t test). Mechanistically, miR-382 overexpression inhibits extracellular matrix degradation by melanoma cells. Moreover, we identified actin regulators CTTN, RAC1, and ARPC2 as direct targets of miR-382. Depletion of CTTN partially recapitulates miR-382 effects on matrix remodeling, invasion, and metastasis. Inhibition of miR-382 in a weakly tumorigenic melanoma cell line increased tumor progression and metastasis in vivo. CONCLUSIONS: Aberrant expression of specific microRNAs that can functionally impact progression of primary melanoma occurs as an early event of melanomagenesis.

Heat-shock factor 1 (HSF1) orchestrates the heat-shock response in eukaryotes. Although this pathway has evolved to help cells adapt in the presence of challenging conditions, it is co-opted in cancer to support malignancy. However, the mechanisms that regulate HSF1 and thus cellular stress response are poorly understood. Here we show that the ubiquitin ligase FBXW7alpha interacts with HSF1 through a conserved motif phosphorylated by GSK3beta and ERK1. FBXW7alpha ubiquitylates HSF1 and loss of FBXW7alpha results in impaired degradation of nuclear HSF1 and defective heat-shock response attenuation. FBXW7alpha is either mutated or transcriptionally downregulated in melanoma and HSF1 nuclear stabilization correlates with increased metastatic potential and disease progression. FBXW7alpha deficiency and subsequent HSF1 accumulation activates an invasion-supportive transcriptional program and enhances the metastatic potential of human melanoma cells. These findings identify a post-translational mechanism of regulation of the HSF1 transcriptional program both in the presence of exogenous stress and in cancer.