Stephen A. Rosenberg

Chitinase 3-like 1 Regulates Cellular and Tissue Responses via IL-13 Receptor α2

SUMMARY Members of the 18 glycosyl hydrolase (GH 18) gene family have been conserved over species and time and are dysregulated in inflammatory, infectious, remodeling, and neoplastic disorders. This is particularly striking for the prototypic chitinase-like protein chitinase 3-like 1 (Chi3l1), which plays a critical role in antipathogen responses where it augments bacterial killing while stimulating disease tolerance by controlling cell death, inflammation, and remodeling. However, receptors that mediate the effects of GH 18 moieties have not been defined. Here, we demonstrate that Chi3l1 binds to interleukin-13 receptor α2 (IL-13Rα2) and that Chi3l1, IL-13Rα2, and IL-13 are in a multimeric complex. We also demonstrate that Chi3l1 activates macrophage mitogen-activated protein kinase, protein kinase B/AKT, and Wnt/β-catenin signaling and regulates oxidant injury, apoptosis, pyroptosis, inflammasome activation, antibacterial responses, melanoma metastasis, and TGF-β1 production via IL-13Rα2-dependent mechanisms. Thus, IL-13Rα2 is a GH 18 receptor that plays a critical role in Chi3l1 effector responses.

Glutamatergic Pathway Targeting in Melanoma; Single Agent and Combinatorial Therapies

Purpose: Melanoma is a heterogeneous disease where monotherapies are likely to fail due to variations in genomic signatures. B-RAF inhibitors have been clinically inadequate but response might be augmented with combination therapies targeting multiple signaling pathways. We investigate the preclinical efficacy of combining the multikinase inhibitor sorafenib or the mutated B-RAF inhibitor PLX4720 with riluzole, an inhibitor of glutamate release that antagonizes metabotropic glutamate receptor 1 (GRM1) signaling in melanoma cells. Experimental Design: Melanoma cell lines that express GRM1 and either wild-type B-RAF or mutated B-RAF were treated with riluzole, sorafenib, PLX4720, or the combination of riluzole either with sorafenib or with PLX4720. Extracellular glutamate levels were determined by glutamate release assays. MTT assays and cell-cycle analysis show effects of the compounds on proliferation, viability, and cell-cycle profiles. Western immunoblotting and immunohistochemical staining showed apoptotic markers. Consequences on mitogen-activated protein kinase pathway were assessed by Western immunoblotting. Xenograft tumor models were used to determine the efficacy of the compounds in vivo. Results: The combination of riluzole with sorafenib exhibited enhanced antitumor activities in GRM1-expressing melanoma cells harboring either wild-type or mutated B-RAF. The combination of riluzole with PLX4720 showed lessened efficacy compared with the combination of riluzole and sorafenib in suppressing the growth of GRM1-expressing cells harboring the B-RAFV600E mutation. Conclusions: The combination of riluzole with sorafenib seems potent in suppressing tumor proliferation in vitro and in vivo in GRM1-expressing melanoma cells regardless of B-RAF genotype and may be a viable therapeutic clinical combination. Clin Cancer Res; 17(22); 7080–92. ©2011 AACR.

The Glutamate Release Inhibitor Riluzole Decreases Migration, Invasion, and Proliferation of Melanoma Cells

The goal of this study was to examine the effects of metabotropic glutamate receptor-1 (GRM1) blockade on melanoma anchorage-independent growth and invasion. We performed colony and invasion assays using GRM1-expressing melanoma lines and the GRM1-negative UACC930 line. Using the glutamate-release inhibitor Riluzole or the non-competitive GRM1 antagonist BAY 36-7620 we were able to induce considerable inhibition of colony formation and invasion in GRM1-expressing melanoma lines. Neither pharmacological agent induced significant reduction in colony formation or invasion in the GRM1-negative melanoma line, UACC930. Additionally we assessed the efficacy of these inhibitors to inhibit the growth of fresh melanoma tumor samples cultured on a 74-mum nylon mesh. Both Riluzole and BAY 36-7620 significantly inhibited tumor cell growth into the interstitial spaces of the mesh. When repeated with normal mole samples both inhibitors were much less effective in preventing the outgrowth of cells. These experiments show that a specific antagonist of GRM1 (BAY 36-7620) or an inhibitor of glutamate release (Riluzole) can significantly suppress melanoma migration, invasion and colony formation as well as inhibit the proliferation of fresh melanoma cells. These findings, added to our previous work, strengthen the case that GRM1 is a valid therapeutic target in patients with melanoma.

Linguistic Acculturation and Skin Cancer–Related Behaviors Among Hispanics in the Southern and Western United States

OBJECTIVE To examine the association between linguistic acculturation (assessed using the Language Use and Linguistic Preference subscales from the Bidimensional Acculturation Scale for Hispanics) and skin cancer-related behaviors among US Hispanic adults to determine whether, compared with Hispanics denoted as Spanish-acculturated, English-acculturated Hispanics would report less frequent shade seeking and use of sun protective clothing and higher rates of sunscreen use, sunbathing, and indoor tanning. DESIGN Online survey study conducted in September 2011. SETTING Five southern and western US states. PARTICIPANTS A population-based sample of 788 Hispanic adults drawn from a nationally representative web panel. MAIN OUTCOME MEASURES Self-reported sunscreen use, shade seeking, use of sun protective clothing, sunbathing, and indoor tanning. RESULTS Multivariate regression analyses were conducted to examine predictors of the skin cancer-related behaviors. As hypothesized, English-acculturated Hispanics had lower rates of shade seeking and use of sun protective clothing and reported higher rates of sunbathing and indoor tanning than Spanish-acculturated Hispanics. English-acculturated Hispanics and bicultural Hispanics (ie, those with high Spanish and high English acculturation) reported comparably high rates of sunbathing and indoor tanning. Results suggested that bicultural Hispanics seek shade and wear sun protective clothing less often than Spanish-acculturated Hispanics but more often than English-acculturated Hispanics. Acculturation was not associated with sunscreen use. CONCLUSIONS Hispanic adults do not routinely engage in behaviors that reduce their risk of skin cancer. Bicultural and English-acculturated Hispanics are particularly in need of skin cancer prevention interventions.

Identification of T-Cell Factor-4 isoforms that contribute to the malignant phenotype of hepatocellular carcinoma cells

The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms from four HCC cell lines. Functional analysis following transfection and expression in HCC cells revealed distinct effects on the phenotype. The TCF-4J isoform expression produced striking features of malignant transformation characterized by high cell proliferation rate, migration and colony formation even though its transcriptional activity was low. In contrast, the TCF-4K isoform displayed low TCF transcriptional activity; cell proliferation rate and colony formation were reduced as well. Interestingly, TCF-4J and TCF-4K differed by only five amino acids (the SxxSS motif). Thus, these studies suggest that conserved splicing motifs may have a major influence on the transcriptional activity and functional properties of TCF-4 isoforms and alter the characteristics of the malignant phenotype.

Skin cancer surveillance behaviors among US Hispanic adults

BACKGROUND Little skin cancer prevention research has focused on the US Hispanic population. OBJECTIVE This study examined the prevalence and correlates of skin cancer surveillance behaviors among Hispanic adults. METHODS A population-based sample of 788 Hispanic adults residing in 5 southern and western states completed an online survey in English or Spanish in September 2011. The outcomes were ever having conducted a skin self-examination (SSE) and having received a total cutaneous examination (TCE) from a health professional. The correlates included sociodemographic, skin cancer-related, and psychosocial factors. RESULTS The rates of ever conducting a SSE or having a TCE were 17.6% and 9.2%, respectively. Based on the results of multivariable logistic regressions, factors associated with ever conducting a SSE included older age, English linguistic acculturation, a greater number of melanoma risk factors, more frequent sunscreen use, sunbathing, job-related sun exposure, higher perceived skin cancer risk, physician recommendation, more SSE benefits, and fewer SSE barriers. Factors associated with ever having a TCE were older age, English linguistic acculturation, a greater number of melanoma risk factors, ever having tanned indoors, greater skin cancer knowledge, higher perceived skin cancer severity, lower skin cancer worry, physician recommendation, more TCE benefits, and fewer SSE barriers. LIMITATIONS The cross-sectional design limits conclusions regarding the causal nature of observed associations. CONCLUSIONS Few Hispanic adults engage in skin cancer surveillance behaviors. The study highlights Hispanic subpopulations that are least likely to engage in skin cancer surveillance behaviors and informs the development of culturally appropriate interventions to promote these behaviors.

Management of leptomeningeal metastases: Prognostic factors and associated outcomes

Limited data are currently available to direct treatment recommendations in the management of leptomeningeal metastases (LM). Here we review treatment modalities clinicians should understand in order to manage patients with LM. We first describe our institutions experience with the treatment of LM and use this dataset to frame the discussion of LM management. Between 1999 and 2014, 1361 patients with central nervous system metastases were reviewed, 124 (9.1%) had radiographic evidence of LM, and these patients form the cohort for this analysis. Mean age at diagnosis of LM was 52years. Median survival for the entire cohort was 2.3months. The most common primary malignancies were non-small cell lung cancer (25.8%), breast cancer (17.7%), small cell lung cancer (16.9%) and melanoma (8.9%). Univariate analyses demonstrated that greater Karnofsky Performance Status (KPS) (p=0.001) and administration of systemic chemotherapy (p<0.001) resulted in improved median survival. Multivariate Cox analyses revealed that receipt of chemotherapy and a complete course of whole brain radiotherapy (WBRT) (median dose 30Gy in 10 fractions, range 24-40Gy) were predictive of longer survival, (p=0.013 and 0.019, respectively). These data suggest that there is a group of patients with good KPS who may experience significantly longer median survival than expected. Multivariate analysis from this single institution retrospective study demonstrated a benefit for WBRT and chemotherapy in individuals with good KPS. These findings provide contemporary data from a large cohort of LM patients, which may be utilized to guide treatment recommendations, assist in patient counseling and direct future investigations into optimization of treatment regimens.

Targeting Glutamatergic Signaling and the PI3 Kinase Pathway to Halt Melanoma Progression

Our group has previously reported that the majority of human melanomas (> 60%) express the metabotropic glutamate receptor 1 (GRM1) and that the glutamate release inhibitor riluzole, a drug currently used to treat amyotrophic lateral sclerosis, can induce apoptosis in GRM1-expressing melanoma cells. Our group previously reported that in vitro riluzole treatment reduces cell growth in three-dimensional (3D) soft agar colony assays by 80% in cells with wildtype phosphoinositide 3-kinase (PI3K) pathway activation. However, melanoma cell lines harboring constitutive activating mutations of the PI3K pathway (PTEN and NRAS mutations) showed only a 35% to 40% decrease in colony formation in soft agar in the presence of riluzole. In this study, we have continued our preclinical studies of riluzole and its effect on melanoma cells alone and in combination with inhibitors of the PI3 kinase pathway: the AKT inhibitor, API-2, and the mammalian target of rapamycin (mTOR) inhibitor, rapamycin. We modeled these combinatorial therapies on various melanoma cell lines in 3D and 2D systems and in vivo. Riluzole combined with mTOR inhibition is more effective at halting melanoma anchorage-independent growth and xenograft tumor progression than either agent alone. PI3K signaling changes associated with this combinatorial treatment shows that 3D (nanoculture) modeling of cell signaling more closely resembles in vivo signaling than monolayer models. Riluzole combined with mTOR inhibition is effective at halting tumor cell progression independent of BRAF mutational status. This makes this combinatorial therapy a potentially viable alternative for metastatic melanoma patients who are BRAF WT and are therefore ineligible for vemurafenib therapy.

Gadoxetate for direct tumor therapy and tracking with real-time MRI-guided stereotactic body radiation therapy of the liver.

SBRT is increasingly utilized in liver tumor treatment. MRI-guided RT allows for real-time MRI tracking during therapy. Liver tumors are often poorly visualized and most contrast agents are transient. Gadoxetate may allow for sustained tumor visualization. Here, we report on the first use of gadoxetate during real-time MRI-guided SBRT.

Long-term patterns of relapse and survival following definitive intensity-modulated radiotherapy for non-endemic nasopharyngeal carcinoma.

BACKGROUND We report treatment outcomes for a large non-endemic cohort of patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy (IMRT) and chemotherapy. METHODS We identified 177 consecutive patients with newly diagnosed, non-metastatic nasopharyngeal cancer treated with definitive IMRT between 1998 and 2011. Endpoints included local, regional, distant control, and overall survival. RESULTS Median follow-up was 52months. The 3-/5-year actuarial rates of local control, regional control, distant control, and overall survival were 92%/83%, 93%/91%, 86%/83%, and 87%/74%, respectively. The median time to local recurrence was 30months; the annual hazard of local recurrence did not diminish until the 6th year of follow-up. CONCLUSIONS Overall, we observed excellent rates of disease control and survival consistent with initially reported results from our institution. Attaining locoregional control in patients with extensive primary tumors remains a significant clinical challenge. With mature follow-up we observed that more than half of observed local relapses occurred after 2years, a pattern distinct from that of carcinomas arising from other head and neck sites. These findings raise the possibility that patients with NPC may benefit from close follow-up during post-treatment years 3-5.