Efecto aditivo in vitro de Chlorella sorokiniana en combinación con Vincristina sobre la inhibición del crecimiento de células de cáncer de colon HT-29 / In vitro additive effect of Chlorella sorokiniana in combination withVincristine on HT-29 colon cancer cells growth inhibition

Objetivo: Evaluar el efecto in vitro de la combinación deChlorella sorokiniana con Vincristina contra el crecimiento decélulas de cáncer de colon HT-29.Material y método:Chlorella sorokiniana se cultivó enmedio López-Chuken. El efecto inhibitorio de la microalga solay en combinación con Vincristina en el crecimiento tumoral seevaluó mediante la técnica de MTT, contra células de cáncerde colon humano HT-29, y se analizó mediante el softwareSynergyFinder 2.0.Resultados: El crecimiento Chlorella sorokiniana fue cons-tante al día 28 a una temperatura de 34 oC ± 3 oC. El efectoinhibitorio de Vincristina sobre células HT-29 fue del 60% apartir de 0.0037μg/mL. La inhibición por Chlorella sorokinianafue del 60% al 80% a las concentraciones de 106-108.Además, la combinación de Vincristina/Chlorella inhibió el cre-cimiento tumoral entre 70% y 90%, siendo la concentraciónmenor de Chlorella la que mostró un mejor efecto en combi-nación con Vincristina. El análisis de los resultados enSynergyFinder mostró un score de -0.708, determinando unefecto aditivo. Conclusión:Chlorella sorokiniana presenta un efecto adi-tivo en combinación con Vincristina contra la línea de cáncerde colon humano HT-29. La suplementación de C. sorokinianaen la dieta de pacientes con cáncer de colon podría mejorarsu tratamiento y por consecuencia su recuperación (AU)

Objective:To evaluate in vitro the effect of the combina-tion of Chlorella sorokiniana with vincristine on HT-29 coloncancer cells.Material and method:Chlorella sorokininana growth wasconstant on day 28 at a temperature of 34 oC ± 3 oC. Chlorellasorokiniana was cultured in López-Chuken medium. HT-29 cellsgrowth inhibition by the microalga alone or in combination withvincristine was evaluated by the colorimetric reduction MTT as-say, and analyzed using the SynergyFinder 2.0 software. Results:The inhibitory effect of Vincristine on HT-29 cellswas 60% from 0.0037μg/mL. Tumor cells growth inhibition by106 to 108 Chlorella sorokiniana cells ranged from 60% to80%. The combination of vincristine and Chlorella inhibitedtumor cells growth from 70% to 90%, being the lower con-centration of Chlorella the one that showed a better effect incombination with vincristine. The analysis of the results inSynergyFinder showed a score of -0.708, determining an ad-ditive effect.Conclusion: Chlorella sorokiniana has an additive effect incombination with vincristine against the human colon cancerline HT-29. Supplementation of C. sorokiniana in the diet ofpatients with colon cancer may improve their treatment andrecovery (AU)

Effect of Culture Conditions of Lophocereus marginatus Endophytic Fungi on Yield and Anticancer and Antioxidant Activities.

Culture conditions affect the production of secondary metabolites in endophytic fungi. Therefore, the aim of the present study was to evaluate the yield and anticancer and antioxidant activity of endophytic fungi extracts from the cactus Lophocereus marginatus, under different culture conditions. The strains Penicillium citrinum, Aspergillus versicolor, Metarhizium anisopliae, and Cladosporium sp. were fermented in different culture media (potato dextrose agar, Czapeck broth, and malt broth), types of inoculums (spore or mycelium), and shaking conditions (150 rpm or static) for one week. Methanol extracts were obtained from mycelia, which was followed by determining their yields and evaluating their effect on L5178Y-R murine lymphoma cells growth and human peripheral blood mononuclear cells (PBMCs) viability, using the 3-[4,5dimethylthiazol-2-yl]2,5-diphenyl tetrazolium bromide reduction colorimetric assay. In addition, antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl test. We determined the half-maximal inhibitory concentration (IC50) values of tumor cell growth inhibition, the selectivity index (SI), and the antioxidant activity, as compared with the healthy cells control. The best yields were obtained with the Czapeck broth medium in all the evaluated strains, reaching values of 50.3%. Of the 48 extracts evaluated, only seven significantly (p < 0.01) inhibited tumor cell growth (IC50 < 250 µg/mL). A. versicolor extract showed the highest anticancer activity, after culturing spores (IC50 = 49.62 µg/mL; SI = 15.8) or mycelium (IC50 = 69.67 µg/mL; SI = 12.2) in malt broth, under static conditions. Extracts did not present significant antioxidant activity. In conclusion, we showed that culture conditions influenced the anticancer activity of L. marginatus endophytic fungi.

In Vitro Antitumor Activity of Endophytic and Rhizosphere Gram-Positive Bacteria from Ibervillea sonorae (S. Watson) Greene against L5178Y-R Lymphoma Cells.

Plant-associated microorganisms represent a potential source of new antitumor compounds. The aim of the present study was to isolate endophytic and rhizosphere Gram-positive bacteria from Ibervillea sonorae and produce extracts with antitumor activity. Methanol and ethyl acetate extracts were obtained from 28 d bacterial fermentation, after which murine L5178Y-R lymphoma cells growth inhibition was evaluated at concentrations ranging from 15.62 µg/mL to 500 µg/mL by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide reduction colorimetric assay. IC50 and the selectivity index (SI) were calculated and compared with healthy control human peripheral blood mononuclear cells (PBMC). Identification of the isolated strains was performed using the 16S ribosomal gene and by MALDI-TOF MS mass spectrometry. The endophytic and rhizosphere bacterial extracts from strains ISE-B22, ISE-B26, ISE-B27, ISS-A01, ISS-A06, and ISS-A16 showed significant (p < 0.05) L5178Y-R cell growth inhibition, compared with an untreated control. The rhizosphere Micromonospora echinospora isolate ISS-A16 showed the highest (90.48%) percentage of lymphoma cells growth inhibition and SI (19.1) for PBMC, whereas the Bacillus subtilis ISE-B26 isolate caused significant (p < 0.01) growth inhibition (84.32%) and a SI of 5.2. Taken together, results of the present study evidenced antitumor effects by I. sonorae endophytic and rhizosphere bacteria culture extracts. Further research will involve the elucidation of the compounds that exert the antitumor activity and their evaluation in pre-clinical studies.