Proteome of fraction from Tityus serrulatus venom reveals new enzymes and toxins

Tityus serrulatus venom (Ts venom) is a complex mixture of several compounds with biotechnological and therapeutical potentials, which highlights the importance of the identification and characterization of these components. Although a considerable number of studies have been dedicated to the characterization of this complex cocktail, there is still a limitation of knowledge concerning its venom composition. Most of Ts venom studies aim to isolate and characterize their neurotoxins, which are small, basic proteins and are eluted with high buffer concentrations on cation exchange chromatography. The first and largest fraction from carboxymethyl cellulose-52 (CMC-52) chromatography of Ts venom, named fraction I (Fr I), is a mixture of proteins of high and low molecular masses, which do not interact with the cation exchange resin, being therefore a probable source of components still unknown of this venom. Thus, the present study aimed to perform the proteome study of Fraction I from Ts venom, by high resolution mass spectrometry, and its biochemical characterization, by the determination of several enzymatic activities. Methods: Fraction I was obtained by a cation exchange chromatography using 50 mg of crude venom. This fraction was subjected to a biochemical characterization, including determination of L-amino acid oxidase, phospholipase, hyaluronidase, proteases activities and inhibition of angiotensin converting enzyme (ACE) activity. Fraction I was submitted to reduction, alkylation and digestion processes, and the tryptic digested peptides obtained were analyzed in a Q-Exactive Orbitrap mass spectrometer. Data analysis was performed by PEAKS 8.5 software against NCBI database. Results: Fraction I exhibits proteolytic activity and it was able to inhibit ACE activity. Its proteome analysis identified 8 different classes of venom components, among them: neurotoxins (48%), metalloproteinases (21%), hypotensive peptides (11%), cysteine-rich venom protein (9%), antimicrobial peptides (AMP), phospholipases and other enzymes (chymotrypsin and lysozymes) (3%) and phosphodiesterases (2%). Conclusions: The combination of a proteomic and biochemical characterization strategies leads us to identify new components in the T. serrulatus scorpion venom. The proteome of venom´s fraction can provide valuable direction in the obtainment of components in their native forms in order to perform a preliminary characterization and, consequently, to promote advances in biological discoveries in toxinology.(AU)

Lung cancer and smoking: molecular aspects

Lung cancer (LC) is characterized as one of the most common and lethal types of cancers worldwide, with approximately 230.000 new cases each year in the US and 160.000 deaths are estimated for 2012. In Brazil, the outlook is also bleak, with 27,320 new cases expected in 2012, according to the Brazilian National Cancer Institute (INCA). LC is classified into two major histological types: small cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). In addition to sizable mortality and incidence, LC has low 5-year survival rates when compared to other types of common cancers such as breast and prostate, even with recent diagnostic and therapeutic advances. For the survival rate of patients with LC to increase, a greater understanding of the molecular events that lead to the emergence of this malignancy is necessary in order to identify genetic markers involved in tumor progression, and thus enable early detection and to develop new specific therapeutic strategies, allowing for a more individualized treatment in patients with LC. Different situations are classified as risk factors for the development of LC, but unquestionably, the most responsible risk factor for the high incidence of LC in the world population by far is smoking.