Adjuvant therapy: melanoma

The Genetic Basis of Dormancy and Awakening in Cutaneous Metastatic Melanoma

Immune dysregulation, in combination with genetic and epigenetic alterations, induces an excessive proliferation of uncontrolled melanoma cells followed by dissemination of the tumor cells to distant sites, invading organs and creating metastasis. Although immunotherapy, checkpoint inhibitors and molecular targeted therapies have been developed as treatment options for advanced melanoma, there are specific mechanisms by which cancer cells can escape treatment. One of the main factors associated with reduced response to therapy is the ability of residual tumor cells to persist in a dormant state, without proliferation. This comprehensive review aimed at understanding the genetic basis of dormancy/awakening phenomenon in metastatic melanoma will help identify the possible therapeutical strategies that might eliminate melanoma circulating tumor cells (CTCs) or keep them in the dormant state forever, thereby repressing tumor relapse and metastatic spread.

CRISPR/Cas9-Mediated Treatment Ameliorates the Phenotype of the Epidermolytic Palmoplantar Keratoderma-like Mouse

CRISPR/Cas9 has been confirmed as a distinctly efficient, simple-to-configure, highly specific genome-editing tool that has been used to treat monogenetic disorders. Epidermolytic palmoplantar keratoderma (EPPK) is a common autosomal dominant keratin disease resulting from dominant-negative mutation of the KRT9 gene, and it has no effective therapy. We performed CRISPR/Cas9-mediated treatment on a knockin (KI) transgenic mouse model that carried a small indel heterozygous mutation of Krt9, c.434delAinsGGCT (p.Tyr144delinsTrpLeu), which caused a humanized EPPK-like phenotype. The mutation within exon 1 of Krt9 generated a novel protospacer adjacent motif site, TGG, for Cas9 recognition and cutting. By delivering lentivirus vectors (LVs) encoding single-guide RNAs (sgRNAs) and Cas9 that targeted Krt9 sequence into HeLa cells engineered to constitutively express wild-type and mutant keratin 9 (K9), we found the sgRNA was highly effective in reducing expression of the mutant K9 protein in vitro. We injected the LV into the fore-paws of adult KI-Krt9 mice three times every 8 days and found that the expression of K9 decreased ∼14.6%. The phenotypic mitigation was revealed by restoration of the abnormal differentiation and aberrant proliferation of the epidermis. Our data are the first to show that CRISPR/Cas9 is a potentially powerful therapeutic option for EPPK and other PPK subtypes.

Long-lasting complete response of metastatic melanoma to ipilimumab with analysis of the resident immune cells

Even though ipilimumab is a promising antibody used for stage IV melanoma therapy, the response varies and is difficult to predict. We here report on a case of successful treatment with ipilimumab in dacarbazine-resistant metastatic malignant melanoma, including a review of the literature on the long-term treatment results. A 62-year-old patient with a history of a resected lentigo-maligna melanoma 5 years earlier and parotideal metastasis 1 year before was admitted with a newly detected 3.5 cm liver metastasis. Atypical liver resection was performed (R1). Immunohistochemically, CD3+ T-lymphocytes and CD68+ macrophages were detected at the tumour margins and within the parotideal and hepatic melanoma metastases. A sub-analysis of the liver metastasis showed scattered FOX-P3+ regulatory T-lymphocytes as well as multiple CD8+ effector T-cells. Chemotherapy with dacarbazine 1,000 mg/m(2)/day was administered at 4-weeks intervals for 3 months. A follow-up positron-emission computed tomography and liver biopsy revealed melanoma metastases in the liver, lungs, and mediastinum. Compassionate use of ipilimumab was administered at 3 mg/kg every 3 weeks for a total of four doses. After an initial increase in tumour size, most lesions responded, but progressive axillary and cervical lymphadenopathy was observed before complete remission was achieved. Side effects included fatigue, dyspnoea, cough, upper abdominal pain with diarrhoea, and gingival hyperplasia. Now, 36 months after ipilimumab therapy and 8 years after the initial melanoma diagnosis, the tumour did not recur. It would be challenging to hypothesize that long intervals between diagnosis and need for treatment, clinical side effects, an initial increase in tumour size and the presence of intra-tumoural T-cells and macrophages might predict tumour response.

An update on pegylated IFN-α2b for the adjuvant treatment of melanoma

For patients with localized melanoma, excision of the primary tumor, including lymphadenectomy for nodal metastases, is standard treatment. However, patients with large primary tumors (stage IIB and IIC) or stage III melanoma have a relatively poor prognosis owing to the high risk of recurrence. High-dose IFN-α2b and pegylated IFN-α2b (PEG-IFN-α2b) are the only approved options for adjuvant therapy of stage III melanoma, but the lack of comparative data has led to considerable confusion in choosing between these options. In this article, current evidence regarding the pharmacokinetics, efficacy, safety and tolerability of adjuvant PEG-IFN-α2b in patients with melanoma is reviewed, with frequent reference to and comparisons with data using IFN-α2b. Particular focus is given to the pharmacokinetic differences between IFN-α2b and PEG-IFN-α2b and their implications for the treatment of high-risk patients. In addition, emerging evidence suggests that PEG-IFN-α2b therapy may provide clinically significant overall survival benefit for selected high-risk patients.

Time-dependent stabilization of hypoxia inducible factor-1α by different intracellular sources of reactive oxygen species

Intratumoral hypoxia is a major obstacle in the development of effective cancer chemotherapy, decreasing the efficacy of anti-neoplastic drugs in several solid tumours. The hypoxic environment, through its master regulator hypoxia inducible factor-1 (HIF-1), is able to maintain an anti-apoptotic potential through activation of critical genes associated with drug resistance. Besides affecting metabolism and motility of tumour cells, hypoxia also paradoxically increases production of reactive oxygen species (ROS), which contribute to stabilize HIF-1 through a redox-mediated inhibition of its proteolysis. Here we reported that 1% O(2) hypoxia increases the resistance of human metastatic melanoma cells to conventional chemotherapy with etoposide, and that the increase in chemoresistance strongly depends on ROS delivery due to hypoxia. We reported a biphasic redox-dependent role of HIF-1, involving mitochondrial complex III and NADPH oxidase as oxidants sources, synergising in enhancing survival to chemotherapy. The feed-forward loop engaged by hypoxia involves first an HIF-1-dependent vascular endothelial growth factor-A (VEGF-A) autocrine production and, in the later phase, activation of NADPH oxidase from VEGF/VEGFR2 interaction, finally leading to a further redox-dependent long lasting stabilization of HIF-1. We therefore identified a redox-dependent circuitry linking hypoxia-driven ROS to VEGF-A secretion and to enhanced melanoma cell survival to etoposide chemotherapy.

Adjuvant therapy for melanoma

Estimates from the U.S. Surveillance, Epidemiology, and End Results registry suggest that melanoma incidence will reach 70,230 cases in 2011, of whom 8790 will die. The rising incidence and predilection for young individuals makes this tumor a leading source of lost productive years in the society.High-dose interferon-α-2b is the only agent approved for adjuvant therapy for melanoma; the improvement in relapse-free survival has been observed across nearly all published studies and meta-analyses. However, toxicity affects compliance, and current research is focusing on biomarkers that may allow selection of patients with greater likelihood of response and exploring new agents either singly or in combination that may improve on the benefit of interferon.In this article, we review the data for the adjuvant therapy for malignant melanoma--focusing on the results obtained with various regimens testing the several formulations of interferon-α2 and the adjuvant studies of vaccines and radiotherapy. Recent advances in the treatment of metastatic disease have established a role for CTLA-4 blockade and BRAF-inhibition, raising hopes that these agents may have a role in the adjuvant setting. At present, several trials investigating combinations of novel agents with existing immunomodulators are underway.

Management of pegylated interferon alpha toxicity in adjuvant therapy of melanoma

INTRODUCTION

Both native IFNα2b and pegylated IFNα2b (PegIFNα2b) are approved for the adjuvant treatment of high-risk melanoma.

AREAS COVERED

This review compares the toxicity profiles of high-dose IFNα2b (HDI) and PegIFNα2b, and provides recommendations on the management of common PegIFNα2b-related toxicities, based on available clinical data and published literature.

EXPERT OPINION

The toxicity profile of PegIFNα2b at the approved dose (6 μg/kg/week for 8 weeks then 3 μg/kg/week for up to 5 years) is qualitatively similar to HDI in melanoma. The most common adverse events (AEs) are fatigue, anorexia, hepatotoxicity, flu-like symptoms, injection site reactions and depression. However, fatigue and flu-like symptoms appear less severe with PegIFNα2b, and toxicity seems to occur earlier, whereas with HDI toxicity may increase with time. Most AEs can be managed effectively by dose modification and aggressive symptom control. Dosing to tolerance using a three-step dose reduction schedule to maintain an ECOG performance status of 0 - 1 may enable patients experiencing toxicity to remain on treatment; this can be applied readily in clinical practice. PegIFNα2b is therefore a valuable alternative option for adjuvant treatment in melanoma, with a toxicity profile similar to that of HDI overall but a more convenient administration schedule.