Chemotherapy For Melanoma Research Articles

Melanoma Chemotherapy Leads to the Selection of ABCB5-Expressing Cells

Metastatic melanoma is the most aggressive skin cancer. Recently, phenotypically distinct subpopulations of tumor cells were identified. Among them, ABCB5-expressing cells were proposed to display an enhanced tumorigenicity with stem cell-like properties. In addition, ABCB5+ cells are thought to participate to chemoresistance through a potential efflux function of ABCB5. Nevertheless, the fate of these cells upon drugs that are used in melanoma chemotherapy remains to be clarified. Here we explored the effect of anti-melanoma treatments on the ABCB5-expressing cells. Using a melanoma xenograft model (WM266-4), we observed in vivo that ABCB5-expressing cells are enriched after a temozolomide treatment that induces a significant tumor regression. These results were further confirmed in a preliminary study conducted on clinical samples from patients that received dacarbazine. In vitro, we showed that ABCB5-expressing cells selectively survive when exposed to dacarbazine, the reference treatment of metastatic melanoma, but also to vemurafenib, a new inhibitor of the mutated kinase V600E BRAF and other various chemotherapeutic drugs. Our results show that anti-melanoma chemotherapy might participate to the chemoresistance acquisition by selecting tumor cell subpopulations expressing ABCB5. This is of particular importance in understanding the relapses observed after anti-melanoma treatments and reinforces the interest of ABCB5 and ABCB5-expressing cells as potential therapeutic targets in melanoma.

The role of phase I clinical trials in advanced malignant melanoma: Retrospective analysis of CTEP-sponsored trials 1995-2011.

2606 Background: Standard chemotherapy for melanoma is DTIC (RR ~10%). Many physicians do not refer to phase I due to perceived limited clinical benefit (CB=CR+PR+SD) and increased toxicity. To understand the actual experience of melanoma patients (pts) in phase I trials, we analyzed the outcomes of melanoma pts treated on CTEP phase 1 trials (1995-2011) and compared them to DTIC. Methods: We queried the CTMS of CTEP for phase I trials in which advanced melanoma pts were treated. Trials were separated into targeted (T), chemo (C) and immunotherapy (I). Pt characteristics, response and toxicity data were collected. Chemotherapy included chemo with targeted or immunotherapy. Toxicity was drug related if attributed possibly, probably or definitely to drug. Fisher’s Exact Test (2-sided p) was used to compare groups. DTIC data was pooled from 6 modern phase III clinical trials (1999-2011). Results: 937 pts (M595:F342) participated in 148 trials (T: 68, C: 53, I: 27). Characteristics included (median) Age: 51.5 yrs; ECOG status: 0; Prior therapies: 2 (majority receiving prior DTIC); LDH: 206 and albumin: 4.1. Response and toxicity data are shown in the Table. Targeted therapy was associated with lower RR (p=.01), immuno with lower CB rate (p<.001) and chemo with higher incidence of G4 toxicity (p<.001) relative to the other groups. Comparing phase 1 to DTIC, RR and CB were not clinically different (phase I: 6.3% and 26.8% vs. DTIC: 8.8% and 27.9%) but G3-4 toxicity was significantly higher (54% vs. 28%) in phase I (p<.0001). Conclusions: Melanoma pts in prior CTEP phase I trials, a majority DTIC pre-treated, had similar therapeutic benefit but more toxicity compared to DTIC naïve pts in modern clinical trials. [Table: see text]

Abstract 1833: A large-scale synthetic lethal RNAi screening identifies unique sensitizing targets for anti-inflammatory CDDO-Me in metastatic melanoma

Abstract Metastatic melanoma is the most lethal form of skin cancer strongly associated with the inflammatory process by secreting high levels of proinflammatory cytokines and producing reactive oxygen and nitrogen species. Chronic inflammation is considered as a major factor to promote the tumor microenvironment in advantage of resistance to radiation, chemotherapy, and biotherapy for metastatic melanoma. CDDO-Me, a novel synthetic triterpenoid, has been shown to exert potent anti-inflammatory and antitumor activity by decreasing oxidative stress and the production of pro-inflammatory molecules, such as Nrf2 and iNOS, in several tumor models. CDDO-Me is presently under evaluation in clinical studies for chronic kidney disease and pancreatic cancer. Here, we used CDDO-Me as a primary agent to inhibit metastatic melanoma growth. In order to improve CDDO-Me response in melanoma cells, we utilized a large-scale synthetic lethal RNAi screen with 24,000 siRNAs targeting ∼6,000 human druggable genes to identify targets that when silenced would sensitize melanoma cells to CDDO-Me. Results from the screens identified twenty of siRNA pools that significantly potentiated the growth inhibitory effects of CDDO-Me in A375 cells. We selected five unique genes, GNPAT, SUMO1, SPUNT2, FLI1, and SSX1, which have not been addressed as drug targets in melanoma before, for target validation and functional analysis in four metastatic melanoma and control cell lines. Specific siRNA against each of these five genes could substantially sensitize four tested melanoma cells to CDDO-me by increasing the growth inhibition and induction of apoptosis, while treatment with nontarget siRNA resulted in no change compared to the treatment with CDDO-Me only. Further studies of downstream signaling revealed that these five genes involved in regulating melanoma cell proliferation and cell death. We identified for the first time that the levels of phosphorylated Erk1/2, Akt, GSK-2, and PRAS40, were dramatically decreased by individual siRNA against GNPAT, SUMO1, SPUNT2, FLI1, and SSX1. Our findings indicate that GNPAT, SUMO1, SPUNT2, FLI1, and SSX1 may play critical roles in synergy with inflammation pathways in modulating melanoma cell survival, which could serve as sensitizing targets to enhance CDDO-Me efficacy in melanoma. Supported by MDACC SPORE in Melanoma P50CA093459. 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 1833. doi:1538-7445.AM2012-1833

Abstract 1641: Concordance between mutations identified by bar-coded multiplexed sequencing of BRAF, NRAS, and KIT in formalin fixed (FFPE) tissue from melanoma patients using the Ion Torrent Personal Genome Machine (PGM) and a real-time PCR assay

Abstract The standard chemotherapy for metastatic melanoma is dacarbazine, however, progression free survival with dacarbazine is a dismal two months. Efforts to improve the treatment of melanoma have focused on specific molecular defects following the discovery that the majority of patients have a mutation in one of three members of the BRAF-MAPK signaling pathway: KIT, BRAF, and RAS. Recent clinical trials have shown promise for drugs that target the molecular defects in melanoma, including the recently approved mutant BRAF inhibitor vemurafenib. As new drugs that target specific mutations move through clinical trials, the opportunity to perform precision medicine is becoming a reality. To deliver on the promise shown by the new generation of drugs it will be necessary to detect specific mutations in patients so they can be matched with the right drug. To this end, we have used an Ion Torrent Personal Genome Machine to sequence the six most commonly mutated codons in melanoma (BRAF 600, NRAS 12 and 13, NRAS 61, KIT 576, and KIT 642) from formalin fixed paraffin embedded tissue of late stage melanoma patients. All six codons of interest were sequenced in forty-six patients and mutations identified by comparison to normal controls. The A375 cell line, containing the known mutation V600E in BRAF was used as a positive control. Samples were sequenced in a multiplexed format using bar coding of the amplicons which allowed 14 patients and two controls to be sequenced simultaneously on each chip. Results were confirmed by real time RT-PCR assay specific for the BRAF V600E mutation. We demonstrate the feasibility of using rapid low cost next-generation sequencing to provide robust detection of mutations in fixed patient samples. 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 1641. doi:1538-7445.AM2012-1641

Patterns of Recurrence Following Complete Response to Regional Chemotherapy for In-Transit Melanoma

Even after complete response (CR) to regional chemotherapy for in-transit melanoma, many patients develop recurrence. Understanding the probability, location, and timing of recurrences can optimize management strategies for this patient population. A prospective database identified patients who underwent 81 first-time hyperthermic isolated limb perfusions (HILPs) and 133 first-time isolated limb infusions (ILIs). Response was defined using the response evaluation criteria in solid tumors; recurrence was defined as development of new disease after in-field CR. HILP exhibited a significantly higher CR rate than ILI (44 vs. 28 %, p = .01). Among 36 HILP-CRs and 37 ILI-CRs, the 3-year recurrence rate was 65 % (95 % confidence interval [95 % CI]: 43-79 %) and 85 % (95 % CI: 63-94%), respectively. Median time to first recurrence was longer for HILP-CR than ILI-CR (23 vs. 8 months, p = .02). There was no statistically significant difference in median time to in-field recurrence between HILP-CR and ILI-CR (46 vs. 25 months, p = .15), but HILP-CR showed a longer median time to out-of-field recurrence (42 vs. 14 months, p = .02). Finally, the overall survival (OS) difference between HILP-CR and ILI-CR (3-year survival: 77 vs. 54 %) did not achieve statistical significance (p = .10). In the largest series comparing patterns of recurrence, we demonstrate that out-of-field recurrence after CR to HILP occurs later than after CR to ILI, though control of in-field disease remains similar. There remains no statistically significant difference in overall survival after CR to the 2 procedures.

Predicting Disease Progression After Regional Therapy for In-Transit Melanoma

Introduction: While approximately 30-50% of patients experience complete response after regional chemotherapy for in-transit melanoma, a subset of patients will develop rapidly progressive disease (PD). in the current era of an expanding armamentarium including both regional and systemic options for treating advanced melanoma, identifying perioperative factors that predict disease progression may obviate unnecessary morbidity associated with regional therapy and avoid delays in systemic therapy.

A Multi-institutional Experience of Repeat Regional Chemotherapy for Recurrent Melanoma of Extremities

Hyperthermic isolated limb perfusion (HILP) or isolated limb infusion (ILI) are well-accepted regional chemotherapy techniques for in-transit melanoma of extremity. The role and efficacy of repeat regional chemotherapy for recurrence and which salvage procedure is better remains debatable. We aimed to compare toxicities and clinical outcomes by procedure types and the sequence. Data from 44 patients, who underwent repeat HILPs or ILIs from 3 institutions beginning 1997 to 2010, were retrospectively reviewed. Regional toxicity assessed by Wieberdink grade, systemic toxicity assessed by serum creatine phosphokinase level, length of hospital stay (LOS), response rates at 3 months after the procedure, and time to in-field progression (TTP) were analyzed. Of 44 patients, 46% were men and 54% women with a median age of 66 (range 29-85) years at diagnosis. The median follow-up was 21.4 (range 4-153) months. Of 70 ILIs and 28 HILPs, the following groups were identified: group A, ILI → ILI (n = 25); group B, ILI → HILP (n = 10); group C, HILP → ILI (n = 12); and group D, HILP → HILP (n = 3). The comparison of Wieberdink grade, serum creatine phosphokinase level, LOS, and response rate between procedures (HILP vs. ILI), between sequence (initial vs. repeat), and among their interactions showed no statistically significant differences. TTP after initial procedure did not differ between HILP and ILI (P = 0.08), and no survival difference was seen (P = 0.65) when TTP after repeat procedure was compared. Most patients tolerated repeat regional chemotherapy without increased toxicity or LOS. No statistical difference in clinical outcomes was noted when comparing repeat procedures, even though repeat HILPs showed higher complete response compared to repeat ILIs.

9323 POSTER Enhanced in Vitro and in Vivo Cytotoxicity of Combined Vaccinia Virus Strain GLV-1h68 and Chemotherapy in Melanoma

9323 POSTER Enhanced in Vitro and in Vivo Cytotoxicity of Combined Vaccinia Virus Strain GLV-1h68 and Chemotherapy in Melanoma

Quantified Visual Scoring of Metastatic Melanoma Patient Treatment Response Using Computed Tomography: Improving on the Current Standard

To assess whether quantitative visual scoring (QVS) is a better early predictor of progression-free survival (PFS) in patients on chemotherapy for metastatic melanoma using CT than the currently used Response Evaluation Criteria in Solid Tumors (RECIST) standard. Retrospective evaluation of 65 consecutive patients with metastatic melanoma on treatment who had a baseline and follow-up CT after two cycles of therapy. QVS was used to code imaging findings on the radiology reports considering size change, brain metastases, new lesions, mixed lesion response, and the number of organ systems involved. RECIST 1.1 criteria placed patients in the progressive disease, stable disease, or partial response groups. Multiple regression analysis was used to correlate the various independent variables with PFS. The Cox hazard proportions ratio, median survival, and Kaplan-Meier curves of the different prognostic groups were calculated. QVS of size change was found more sensitive in detecting patients deteriorating (57.1% versus 37.5%) or improving (23.8% versus 10.7%), more correlated with the median PFS for the deteriorating (1.8 versus 1.7 months), stable (5.6 versus 4.0 month), and improving (8.3 versus 5.5 months) categories and more predictive of PFS (Cox hazard proportion ratio of 3.070 versus 1.860) than RECIST 1.1 categorization. Multiple regression analysis demonstrated QVS of lesion size correlated most closely with PFS among the variables assessed (r = 0.519, p < 0.0001). QVS in this study was superior to standard RECIST categorization in terms of discriminating treated metastatic melanoma patients likely to have longer PFS.

P035. Melanoma chemotherapy leads to the selection of ABCB5-expressing cells

P035. Melanoma chemotherapy leads to the selection of ABCB5-expressing cells

Abstract 733: A therapeutic opportunity in melanoma: Targeting CXCR1/2-dependent signaling attenuates therapy resistance

Abstract Advanced melanoma is one of the most intractable tumors, due to its insensitivity to all current treatment. Systemic chemotherapy is still considered the mainstay of treatment for advanced melanoma with limited survival impact. Failure of most agents is attributed to development of therapy resistance. Our previous findings demonstrate that CXCL-8 is a critical mediator in tumor growth, invasion, and angiogenesis. Two high affinity receptors for CXCL-8, CXCR1 and CXCR2, are differentially expressed on melanoma and endothelial cells. Based on these observations, we hypothesize that targeting CXCR1/2-dependent signaling will attenuate chemotherapy resistance and will synergistically enhance chemotherapeutic response for malignant melanoma. We used human melanoma cell lines A375P (low metastatic) and A375SM (highly metastatic), which express low and high levels of CXCL-8 respectively. First, we evaluated the role of CXCR1/2 ligands in chemo-resistance. CXCL-1 and -8 mRNA and protein expression was analyzed by quantitative realtime PCR and enzyme-linked immunosorbant assay, following treatment of dacarbazine and temozolomide. A significant increase in the CXCL-1 and -8 levels was observed in A375P and A375SM cells which was dependent on concentration and duration of chemotherapeutic treatment. In order to test whether blocking CXCR1/2 expression using genetic knock-down modulates chemotherapeutic responses, we used A375SM cells expressing different levels of CXCR1 and CXCR2. Our data suggest that knockdown of CXCR1 significantly enhanced the cytotoxic effect of dacarbazine in vitro. However, we did not observe a similar response in melanoma cells knocked down for CXCR2. Taken together, our preliminary data demonstrate that melanoma cells that survive chemotherapy express higher levels of CXCR1/2 ligands and targeting the CXCR1/2-dependent pathway might be a potential therapeutic approach to be combined with chemotherapy in advanced melanoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 733. doi:10.1158/1538-7445.AM2011-733

Synergistic inhibition of malignant melanoma proliferation by melphalan combined with ultrasound and microbubbles

The cavitational effects of ultrasound (US) exposure induce transient pores on the cell membrane (sonoporation). Sonoporation have been applied in the field of cancer therapy by promoting delivery of extracellular molecules such as drugs and genes into cytoplasm. In addition, it is known that using US together with microbubbles (MB) elevates permeability of these agents. In this study, by applying the US–MB strategy for melanoma chemotherapy, we evaluated the antitumor effect of melphalan combined with US–MB on a melanoma cell line (C32) in vitro and in vivo. The in vitro cytotoxic effect of the melphalan with US–MB was greater than that of melphalan alone or melphalan in combination with US. In vivo experiments using xenografts, intratumoral injection of melphalan and MB with US exposure led to a greater degree of tumor regression than did the intratumoral injection of the melphalan alone or melphalan in combination with US. These results suggest that US–MB promotes the antitumor effect of melphalan by increasing delivery of molecules into cells and that this strategy may become an effective method of adjuvant therapy against malignant melanoma.

Cellular markers based on DNA repair (BER, MMR) expression of MLH1, MSH2, FasR and death of lymphocytes as predictive parameters for clinical response to chemotherapy of melanoma patients

Melanoma is a highly aggressive tumor of melanocytes. The efficacy of different cytotoxic chemotherapy regimens does not exceed 20%. The search for markers for patient sensitivity to chemotherapy provides a rational basis for the development of cytotoxic chemotherapy. In this study, we evaluated six blood lymphocyte parameters (the efficacy of BER and MMR; the expression of MLH1, MSH2, FasR; and cell death) as prognostic markers for melanoma chemotherapy. We found that chemotherapy induced AP sites and ssDNA breaks in lymphocytes repaired through the BER pathway. However, ssDNA breaks were completely repaired after chemotherapy and, therefore, did not contribute to the toxic effect of chemotherapy. dsDNA breaks produced by a functioning MMR system appeared downstream of methylation adducts, which was confirmed by the linear correlation of these parameters in various patients. The number of dsDNA breaks, but not MMR, MLH1, and MSH2 expression, correlated to the efficacy of chemotherapy. A positive correlation was observed between lymphocyte death induced by chemotherapy and the patient’s clinical response, which may show that the nucleotide excision repair (NER) mechanism is implicated in the generation of double-strand breaks and the cytotoxic effect of chemotherapy.

SiRNA Knockdown of Ribonucleotide Reductase Inhibits Melanoma Cell Line Proliferation Alone or Synergistically with Temozolomide

Systemically delivered small interfering RNA (siRNA) therapies for cancer have begun clinical development. The effects of siRNA-mediated knockdown of ribonucleotide reductase subunit-2 (RRM2), a rate-limiting enzyme in cell replication, were investigated in malignant melanoma, a cancer with a paucity of effective treatment options. A panel of human melanoma cell lines was transfected with siRNA to induce the knockdown of RRM2. Sequence-specific, siRNA-mediated inhibition of RRM2 effectively blocked cell proliferation and induced G1/S-phase cell cycle arrest. This effect was independent of the activating oncogenic mutations in the tested cell lines. Synergistic inhibition of melanoma cell proliferation was achieved using the combination of siRNA targeting RRM2 and temozolomide, an analog of the current standard of care for melanoma chemotherapy. In conclusion, siRNA-mediated RRM2 knockdown significantly inhibits proliferation of melanoma cell lines with different oncogenic mutations with synergistic enhancement in combination with temozolomide.

Systemic Bevacizumab Synergistically Augments Regionally Delivered Chemotherapy For Malignant Melanoma

Systemic Bevacizumab Synergistically Augments Regionally Delivered Chemotherapy For Malignant Melanoma

Anti-DR5 monoclonal antibody-mediated DTIC-loaded nanoparticles combining chemotherapy and immunotherapy for malignant melanoma: target formulation development and in vitro anticancer activity

BackgroundThe increased incidence of malignant melanoma in recent decades, along with its high mortality rate and pronounced resistance to therapy pose an enormous challenge. Novel therapeutic strategies, such as immunotherapy and targeted therapy, are urgently needed for melanoma. In this study, a new active targeting drug delivery system was constructed to combine chemotherapy and active specific immunotherapy.MethodsThe chemotherapeutic drug, dacarbazine (DTIC), that induces apoptosis through the intrinsic pathway which typically responds to severe DNA damage, was used as a model drug to prepare DTIC-loaded polylactic acid (PLA) nanoparticles (DTIC-NPs), which were covalently conjugated to a highly specific targeting functional TRAIL-receptor 2 (DR5) monoclonal antibody (mAb) that can contribute directly to cancer cell apoptosis or growth inhibition through the extrinsic pathway.ResultsOur in vitro experiments demonstrated that DTIC-PLA-DR5 mAb nanoparticles (DTIC-NPs-DR5 mAb) are an active targeting drug delivery system which can specifically target DR5-overexpressing malignant melanoma cells and become efficiently internalized. Most strikingly, compared with conventional DTIC-NPs, DTIC-NPs-DR5 mAb showed significantly enhanced cytotoxicity and increased cell apoptosis in DR5-positive malignant melanoma cells.ConclusionThe DTIC-NPs-DR5 mAb described in this paper might be a potential formulation for targeting chemotherapy and immunotherapy to DR5-overexpressing metastatic melanoma.

VEGFR2 heterogeneity and response to anti-angiogenic low dose metronomic cyclophosphamide treatment

BackgroundTargeting tumor vasculature is a strategy with great promise in the treatment of many cancers. However, anti-angiogenic reagents that target VEGF/VEGFR2 signaling have met with variable results clinically. Among the possible reasons for this may be heterogeneous expression of the target protein.MethodsDouble immunofluorescent staining was performed on formalin-fixed paraffin embedded sections of treated and control SW480 (colorectal) and WM239 (melanoma) xenografts, and tissue microarrays of human colorectal carcinoma and melanoma. Xenografts were developed using RAG1-/- mice by injection with WM239 or SW480 cells and mice were treated with 20 mg/kg/day of cyclophosphamide in their drinking water for up to 18 days. Treated and control tissues were characterized by double immunofluorescence using the mural cell marker α-SMA and CD31, while the ratio of desmin/CD31 was also determined by western blot. Hypoxia in treated and control tissues were quantified using both western blotting for HIF-1α and immunohistochemistry of CA-IX.ResultsVEGFR2 is heterogeneously expressed in tumor vasculature in both malignant melanoma and colorectal carcinoma. We observed a significant decrease in microvascular density (MVD) in response to low dose metronomic cyclophosphamide chemotherapy in both malignant melanoma (with higher proportion VEGFR2 positive blood vessels; 93%) and colorectal carcinoma (with lower proportion VEGFR2 positive blood vessels; 60%) xenografts. This reduction in MVD occurred in the absence of a significant anti-tumor effect. We also observed less hypoxia in treated melanoma xenografts, despite successful anti-angiogenic blockade, but no change in hypoxia of colorectal xenografts, suggesting that decreases in tumor hypoxia reflect a complex relationship with vascular density. Based on α-SMA staining and the ratio of desmin to CD31 expression as markers of tumor blood vessel functionality, we found evidence for increased stabilization of colorectal microvessels, but no such change in melanoma vessels.ConclusionsOverall, our study suggests that while heterogeneous expression of VEGFR2 is a feature of human tumors, it may not affect response to low dose metronomic cyclophosphamide treatment and possibly other anti-angiogenic approaches. It remains to be seen whether this heterogeneity is partly responsible for the variable clinical success seen to date with targeted anti-VEGFR2 therapy.

Therapy-related myelodysplastic syndrome developed by dacarbazine, nimustine hydrochloride and vincristine sulfate (DAV) therapy for patient with malignant melanoma

Therapy-related myelodysplastic syndrome (t-MDS) is mostly attributed to chemotherapeutic agents of alkylating agents. Few studies have evaluated the late effects of chemotherapy for malignant melanoma (MM). To evaluate whether dacarbazine, nimustine hydrochloride and vincristine sulfate (DAV) therapy for MM related to t-MDS or not, a retrospective analysis was performed. We conducted a retrospective case-control study in a cohort of the 217 patients diagnosed with MM from 1989-2007 in Aichi Medical University Department of Dermatology and Nagoya University Graduate School of Medicine Department of Dermatology. One hundred and fifty-five of the 217 patients with MM were prospectively followed after DAV therapy or with or without local injection of β-interferon, of whom two patients developed t-MDS. Cytogenetic abnormalities were found in two of the 35 patients by chromosome banding method - leukemia (G-Banding). The karyotypes were found in the chromosome of -5, deletion (5), addition (7) and 7q-. In conclusion, DAV therapy should be used carefully for older patients with MM after satisfactory operation.

Clinical Development of the Anti–CTLA-4 Antibody Tremelimumab

Tremelimumab (formerly CP-675,206) is a fully human IgG2 monoclonal antibody tested in patients with cancer, of whom the majority have had metastatic melanoma. Clinical trials using tremelimumab demonstrate that this antibody can induce durable tumor regressions (up to 8 years at this time) in 7% to 10% of patients with metastatic melanoma. These tumor responses are mediated by the intratumoral infiltration of cytotoxic T lymphocytes (CTLs) as demonstrated in patient-derived tumor biopsies. Grade 3 or 4 toxicities in the range of 20% to 25% are mainly inflammatory or autoimmune in nature, which are on-target effects after inhibiting CTLA-4-mediated self-tolerance. The lack of survival advantage in the early analysis of a phase III clinical trial comparing tremelimumab with standard chemotherapy for metastatic melanoma highlights the importance of gaining a better understanding of how this antibody modulates the human immune system and how to better select patients for this mode of therapy.

Enhancing Melanoma Treatment with Resveratrol

Resveratrol (RESV) is a naturally occurring compound that possesses anti-cancer capabilities. The goal of this study was to evaluate the potential of RESV as an adjunct to chemotherapy in melanoma treatment. The in vitro and in vivo cytotoxic activity of RESV with or without chemotherapy was tested using cellular assays and a xenograft model. Two Duke melanoma cell lines (DM738, DM443) were used for both in vivo and in vitro experiments, and two nonmalignant human fibroblast lines (NHDF, HS68) were used for in vitro cellular assays. Xenografts were randomized to treatment arms and tumors measured to evaluate response. Results were analyzed using a Student's t-test and ANOVA. Western blots were performed on in vivo tissue. In vitro RESV significantly decreased melanoma cell viability in all lines tested (all P < 0.0001). Treatment of fibroblast cell lines revealed that RESV selectively spared NHDF and HS68 cells compared with its cytotoxic effects on melanoma cells (P < 0.0001). Treatment of malignant cells with 50 μM RESV and temozolomide (TMZ) for 72 h significantly enhanced cytotoxicity compared with treatment with TMZ alone (P < 0.0001). In vivo, however, there was no significant difference between any treatment arms (P = 0.65). RESV shows promise as a novel therapeutic in the management of melanoma for its selective anti-tumor activity in vitro. Translating in vitro results to in vivo models has proven difficult. Barriers thought to prevent such translation are identified, and a rationale for overcoming them is discussed.