Marine microbes are capable of degrading hydrocarbons; however, those inhabiting the deep biosphere (>1000 m) remain largely unexplored. Microbial metabolism could lead to the generation of diverse chemistries (some with therapeutic activities), but the impact of using hydrocarbons as the sole source of microbial energy in the synthesis of metabolites, remains obscure. Here, we investigated the metagenomic and metabolomic profile of two deep-marine sediments (>1 200 m deep, designated as A7 and B18) collected from the Gulf of México (GM) when grown for 28 days with a simple mixture of 4 hydrocarbons and complex hydrocarbon mixture (petroleum API 40) as their sole source of energy. State of the art techniques and analysis (e.g., Global Natural Products Social Molecular Networking, network annotation propagation [NAP], and MS2LDA) were used to describe the chemistries associated to the microbial utilization of hydrocarbons. The metagenomic sequencing analysis suggests a predominant abundance of Proteobacteria in environmental and API 40-enriched samples, while the abundance of Pseudomonas increased after microbial growth with API 40. The metabolomic analysis suggests the presence of diverse chemistries predominantly associated with lipid and lipid-like and phenyl propanoids and polyketides superclass (Classyfire annotation). Hydrocarbon derivatives were detected as carboxylic acids (e.g., azelaic and sebacic acid) or alcohols, while non-hydrocarbon related chemistries were also detected including tetracycline-related metabolites and sphinganines. Our study provides valuable chemical and microbiological information of microbes inhabiting one of the most understudied ecosystems in the earth, the deep marine biosphere.

Malignant pleural mesothelioma (MPM) is a rare neoplasm with increasing incidence and mortality rates. Although recent advances have improved the overall prognosis, they have not had an important impact on survival of patients with MPM, such that more effective treatments are needed. Some species of marine snails have been demonstrated to be potential sources of novel anticancer molecules. This study analyzed the anticancer effects in vitro and in vivo of two peptides found in C. californicus. The effects of s-cal14.1b and s-cal14.2b on cell proliferation, apoptosis, and cytotoxicity were evaluated in 2D and 3D cultures of MPM-derived cells. Proteomics analysis of 3D cultures treated with conotoxins was performed to examine changes in expression or abundance. And the therapeutic effects of both conotoxins were evaluated in MPM mouse xenografts. s-cal14.1b and s-cal14.2b induced apoptosis and cytotoxicity in 2D and 3D cultures. However, only s-cal14.1b modified spheroid growth. Approximately 600 proteins exhibited important differential expression, which was more heterogeneous in H2452 vs MSTO-211H spheroids. The in silico protein functional analysis showed modifications in the biological pathways associated with carcinogenesis. CAPN1, LIMA1, ANXA6, HUWE1, PARP1 or PARP4 proteins could be potential cell targets for conotoxins and serve as biomarkers in MPM. Finally, we found that both conotoxins reduced the tumor mass in MPM xenografts; s-cal14.1b reached statistical significance. Based on these results, s-cal14.1b and s-cal14.2b conotoxins could be potential therapeutic drugs for MPM neoplasms with no apparent side effects on normal cells.