Fruit Extract of Sechium chinantlense (Lira & F. Chiang) Induces Apoptosis in the Human Cervical Cancer HeLa Cell Line.

Sechium edule (Cucurbitaceae) is a commercial species of chayote and is just one of several species in the genus Sechium, whose extracts inhibit proliferation in tumor cell lines. The capacity of the wild species Sechium chinantlense (SCH) as an antitumor agent is unknown, as is the mechanism of action. In the present study, HeLa cervical cancer and HaCaT normal cell lines were treated with SCH and cell proliferation was inhibited in both cell lines in a dose-dependent manner similar to the effect of the antineoplastic agent cisplatin (Cis). Additionally, SCH arrested cell cycle progression but only in HeLa cells and induced apoptosis, as shown by phosphatidylserine translocation and caspase-3 activation, while Cis did so in both cell lines. Exploration of the mechanism of action of SCH in HeLa cells suggests that apoptosis was mediated by the intrinsic signaling pathway since there was no activation of caspase-8, but there was a release of cytochrome-c. These findings suggest that the SCH extract has the potential to selectively kill tumor cells by promoting apoptosis, without harming nontumor cells.

Casein and Peptides Derived from Casein as Antileukaemic Agents.

Milk is a heterogeneous lacteal secretion mixture of numerous components that exhibit a wide variety of chemical and functional activities. Casein, the main protein in milk, is composed of α-, ß-, and κ-caseins, each of which is important for nutritional value and for promoting the release of cytokines, also are linked to the regulation of haematopoiesis and immune response and inhibit the proliferation and induce the differentiation of leukaemia cells. It has been shown that the digestive process of caseins leads to the release of bioactive peptides that are involved in the regulation of blood pressure and the inhibition or activation of the immune response by serving as agonists or antagonists of opioid receptors, thus controlling the expression of genes that exert epigenetic control. Later, they bind to opioid receptor, block nuclear factor κ-beta, increase the redox potential, and reduce oxidative stress and the pro-inflammatory agents that favour an antioxidant and anti-inflammatory environment. Therefore, the bioactive peptides of casein could be compounds with antileukaemia potential. This review provides a summary of current knowledge about caseins and casein peptides on the immune system as well as their roles in the natural defence against the development of leukaemia and as relevant epigenetic regulators that can help eradicate leukaemia.

Sechium edule (Jacq.) Swartz, a New Cultivar with Antiproliferative Potential in a Human Cervical Cancer HeLa Cell Line.

The Sechium edule Perla Negra cultivar is a recently-obtained biological material whose progenitors are S. edule var. nigrum minor and S. edule var. amarus silvestrys, the latter of which has been reported to have antiproliferative activity against the HeLa P-388 and L-929 cancer cell lines. The present study aimed to determine if the methanolic extract of the fruit of the Perla Negra cultivar had the same biological activity. The methanolic extract was phytochemically characterized by thin layer chromatography (TLC) and column chromatography (CC), identifying the terpenes and flavonoids. The compounds identified via high performance liquid chromatography (HPLC) were Cucurbitacins B, D, E, and I for the terpene fractions, and Rutin, Phlorizidin, Myricetin, Quercetin, Naringenin, Phloretin, Apigenin, and Galangin for the flavonoid fractions). Biological activity was evaluated with different concentrations of the methanolic extract in the HeLa cell line and normal lymphocytes. The methanolic extract inhibited the proliferation of HeLa cells (IC50 1.85 µg·mL-1), but the lymphocytes were affected by the extract (IC50 30.04 µg·mL-1). Some fractions, and the pool of all of them, showed inhibition higher than 80% at a concentration of 2.11 µg·mL-1. Therefore, the biological effect shown by the methanolic extract of the Perla Negra has some specificity in inhibiting tumor cells and not normal cells; an unusual feature among molecules investigated as potential biomedical agents.