Antiproliferative effect of the jararhagin toxin on B16F10 murine melanoma.

BACKGROUND: Malignant melanoma is a less common but highly dangerous form of skin cancer; it starts in the melanocytes cells found in the outer layer of the skin. Jararhagin toxin, a metalloproteinase isolated from Bothrops jararaca snake venom acts upon several biological processes, as inflammation, pain, platelet aggregation, proliferation and apoptosis, though not yet approved for use, may one day be employed to treat tumors. METHODS: B16F10 murine melanoma cells were treated with jararhagin (jara), a disintegrin-like metalloproteinase isolated from Bothrops jararaca snake venom, and jari (catalytic domain inactivated with 1,10-phenanthroline). Viability and adhesion cells were evaluated by MTT assay. The expression of caspase-3 active, phases of the cell cycle and apoptosis were assessed by flow cytometry. We analyze in vivo the effects of jararhagin on melanoma growth, apoptosis and metastasis. RESULTS: The tumor cells acquired round shapes, lost cytoplasmic expansions, formed clusters in suspension and decreased viability. Jari was almost 20 times more potent toxin than jara based on IC50 values and on morphological changes of the cells, also observed by scanning electron microscopy. Flow cytometry analysis showed 48.3% decrease in the proliferation rate of cells and 47.2% increase in apoptosis (jara) and necrosis (jari), following 1.2 µM jara and 0.1 µM jari treatments. Caspase-3 activity was increased whereas G0/G1 cell cycle phase was on the decline. Proliferative rate was assessed by staining with 5,6-carboxyfluoresceindiacetate succinimidyl ester, showing a significant decrease in proliferation at all concentrations of both toxins. CONCLUSIONS: In vivo treatment of the toxins was observed reduction in the incidence of nodules, and metastasis and antiproliferative inhibition capacity. This data strengthens the potential use jararhagin as an anti-neoplastic drug.

Clinical and genetic characterization of basal cell carcinoma and breast cancer in a single patient.

INTRODUCTION: Multiple environmental and genetic factors are involved with the development of basal cell carcinomas (BCC), as well as with breast cancers. Tumor initiation and progression are often associated with genomic instability such as aneuploidies, and gains or losses of large chromosomal segments, known as copy number alterations (CNAs). CNAs have been successfully detected using the microarray comparative genomic hybridization technique (array-CGH) at high resolution. Data thus obtained are useful to identify specific genomic aberrations, to classify tumor stages, and to stratify subgroups of patients with different prognosis and clinical behaviors. CASE DESCRIPTION: Clinical study of a 66-year-old white female identified two primary tumors, a ductal invasive grade-II carcinoma of the breast, and one nodular BCC. Germline and tumor genomic survey utilized the 180 K array-CGH analysis to investigate chromosomal alterations. DISCUSSION AND EVALUATION: Several chromosomal anomalies were detected in the breast tumor genome, including focal ~422 Kb 13q13.3 microdeletion. In the BCC, amplification of a chromosome 6 spanning the centromere region between the cytobands 6p23 and 6q12 was identified. Several 6p amplified genes correspond to families of histone and human leukocyte antigen genes, whereas some of the CNAs found in the breast tumor are uncommon. No germline CNA was detected in the normal skin of the patient at this technical resolution. CONCLUSION: CNAs found in the two different tumors of the patient constitute independent events arisen in the somatic lineage. Relevant genes to both carcinogenesis and progression are to be affected by these CNAs.

Gene expression in SK-Mel-28 human melanoma cells treated with thesnake venom jararhagin

Alternative approaches to improve the treatment of advanced melanomas are highly needed.The disintegrin domain of metalloproteinases binds integrin receptors on tumor cells,blocking migration, invasion, and metastatization. Previous studies showed that jararhagin,from the Bothrops jararaca snake venom, induces changes in the morphology and viability ofSK-Mel-28 human melanoma cells, and decreases the number of metastases in mice injected with pre-treated cells. The purpose of this study was to evaluate the molecular effects ofjararhagin on SK-Mel-28 cells and fibroblasts, concerning the expression of integrins, cadherins, caspases, and TP53 genes. Sub-toxic doses of jararhagin were administered to confluent cells. RT-PCR was performed following extraction of total RNA. Jararhagin treatmentsinduced similar morphological alterations in both normal and tumor cells, with higher IC50 values for fibroblasts. Integrin genes were downregulated in untreated cells,except for ITGA6a,b, ITGAv, and ITGB3 which were highly expressed in SK-Mel-28. The integrin expression profiles were not affected by the toxin. However, jararhagin 30 ng/mlupregulated genes TP53, CDKN1A, CDKN2A, CASP3, CASP5, CASP6, CASP8, and E-CDH in SKMel-28, and genes ITGB6, ITGB7, CASP3, TP53, and CDKN1B in fibroblasts. Appropriate jararhagin concentration can have apoptotic and suppressant effects on SK-Mel-28 cells, ratherthan on fibroblasts, and can be used to develop potential anti-cancer drugs.

Gene expression in SK-Mel-28 human melanoma cells treated with the snake venom jararhagin.

Alternative approaches to improve the treatment of advanced melanomas are highly needed. The disintegrin domain of metalloproteinases binds integrin receptors on tumor cells, blocking migration, invasion, and metastatization. Previous studies showed that jararhagin, from the Bothrops jararaca snake venom, induces changes in the morphology and viability of SK-Mel-28 human melanoma cells, and decreases the number of metastases in mice injected with pre-treated cells. The purpose of this study was to evaluate the molecular effects of jararhagin on SK-Mel-28 cells and fibroblasts, concerning the expression of integrins, cadherins, caspases, and TP53 genes. Sub-toxic doses of jararhagin were administered to confluent cells. RT-PCR was performed following extraction of total RNA. Jararhagin treatments induced similar morphological alterations in both normal and tumor cells, with higher IC50 values for fibroblasts. Integrin genes were downregulated in untreated cells, except for ITGA6a,b, ITGAv, and ITGB3 which were highly expressed in SK-Mel-28. The integrin expression profiles were not affected by the toxin. However, jararhagin 30ng/µl upregulated genes TP53, CDKN1A, CDKN2A, CASP3, CASP5, CASP6, CASP8, and E-CDH in SK-Mel-28, and genes ITGB6, ITGB7, CASP3, TP53, and CDKN1B in fibroblasts. Appropriate jararhagin concentration can have apoptotic and suppressant effects on SK-Mel-28 cells, rather than on fibroblasts, and can be used to develop potential anti-cancer drugs.

Genética molecular aplicada ao câncer cutâneo não melanoma / Molecular genetics of non-melanoma skin cancer

Os cânceres cutâneos não melanoma são as neoplasias malignas mais comuns em humanos. O carcinoma basocelular e o carcinoma espinocelular representam cerca de 95 por cento dos cânceres cutâneos não melanoma, o que os torna um crescente problema para a saúde pública mundial devido a suas prevalências cada vez maiores. As alterações genéticas que ocorrem no desenvolvimento dessas malignidades cutâneas são apenas parcialmente compreendidas, havendo muito interesse no conhecimento e determinação das bases genéticas dos cânceres cutâneos não melanoma que expliquem seus fenótipos, comportamentos biológicos e potenciais metastáticos distintos. Apresenta-se uma revisão atualizada da genética molecular aplicada aos cânceres cutâneos não melanoma, em especial ao carcinoma basocelular e carcinoma espinocelular, enfatizando os mais freqüentes genes e os principais mecanismos de instabilidade genômica envolvidos no desenvolvimento dessas malignidades cutâneas.

Non-melanoma skin cancers are the most common malignant neoplasms in humans. About 95 percent of all non-melanoma skin cancers are represented by basal cell carcinoma and squamous cell carcinoma. Their prevalences are still increasing worldwide, representing an important public health problem. The genetic alterations underlying basal cell carcinoma and squamous cell carcinoma development are only partly understood. Much interest lies in determining the genetic basis of non-melanoma skin cancers, to explain their distinctive phenotypes, biological behaviors and metastatic potential. We present here a molecular genetic update, focusing on the most frequent genes and genomic instability involved in the development and progression of non-melanoma skin cancers.