Enzymatic and non-enzymatic proteins from Bothrops snake venoms, their anticancer activity, and translational challenges in oncovenomics: A review.

Proteins from Bothrops snake venoms constitute a diverse repertoire of enzymatic and non-enzymatic macromolecules with recognized pharmacological activities and growing interest in cancer research. To critically evaluate their in vitro anticancer potential, a systematic review was conducted following PRISMA 2020 guidelines using PubMed and Scopus databases, resulting in 58 eligible primary studies. The reviewed literature encompassed crude venoms, purified toxins, venom fractions, and synthetic peptides derived principally from L-amino acid oxidases, phospholipases A₂, snake venom metalloproteinases, serine proteases, C-type lectins, and disintegrins. Among these protein families, L-amino acid oxidases and selected phospholipase A₂ isoforms generally exhibited the highest cytotoxic potency across hematological and solid tumor models, whereas metalloproteinases, lectins, disintegrins, and serine proteases displayed more variable but biologically relevant anticancer activities. However, the literature audit revealed substantial methodological heterogeneity, including inconsistent toxin characterization, non-standardized concentration reporting, inconsistent assessment of tumor-versus-normal selectivity, and a strong dependence on single-endpoint metabolic viability assays. To improve comparative interpretation across studies, a multi-level validation framework and methodological quality criteria adapted from OECD (2018) guidance were applied. Under this framework, 22.4% of studies remained restricted to Level I cytotoxicity assessments, 53.4% incorporated Level II functional and cellular validation, and only 24.1% included Level III molecular mechanistic analyses. Overall, the available evidence indicates that Bothrops venom proteins represent promising sources of bioactive anticancer scaffolds; however, significant translational challenges remain. Future oncovenomics studies should prioritize standardized experimental pipelines integrating orthogonal validation, mechanistic characterization, selectivity assessment, and developability criteria to improve reproducibility and pharmacological relevance.