Cancer belongs to a group of diseases characterized by uncontrolled cell growth. The search for new effective treatments for cancer has led to the discovery of different molecules from plants, bacteria, and fungi with pharmacological use. Plant endophytic fungi are large producers of metabolites with antitumor properties. We aimed to evaluate the in vitro and in vivo antitumor potential of extracts from Lophocereus marginatus endophytic fungi. We obtained ethyl acetate and hexane extracts from the L. marginatus endophytes Metarhizium anisopliae and Aspergillus versicolor and evaluated their antitumor activity against murine L5178Y-R lymphoma cells and human peripheral blood mononuclear cells, using the 3-(4,5-dimethylthiazol-2-yl)-2-diphenyltetrazolium bromide reduction colorimetric technique. M. anisopliae and A. versicolor ethyl acetate extracts showed IC₅₀ values of 9.168 ± 1.21 μg/mL and 13.51 ± 1.62, respectively, and selectivity indices > 30. We also observed that the maximum tolerated dose (100 mg/kg) of ethyl acetate extracts and the vehicle in BALB/c mice did not cause hepatotoxicity. In addition, we evaluated the effects of ethyl acetate extracts on survival and tumor volume in the L5178Y-R lymphoma tumor model. An increase in survival (17 d) was observed in mice treated with A. versicolor extract. Furthermore, it did not increase tumor volume during 10 d, as compared with the control groups without treatment, vehicle, and M. anisopliae extract, which had a maximum survival of 10 d. A. versicolor ethyl acetate extract showed in vitro and in vivo antitumor activity against lymphoma L5178Y-R, increasing mice survival.

Glioblastoma is the most common and aggressive brain tumor in adults. However, due to the limitations of conventional treatments, as well as their side effects, there is a need to develop more effective and less harmful therapy strategies. There is evidence that plants endemic to northern Mexico possess biological activities that positively impact human health, particularly against cancer. Echinocereus engelmannii and Echinocereus pectinatus are cacti from the north of Mexico that produce bioactive compounds with antitumor activity. We obtained methanol extracts from previously isolated and fermented microorganisms associated with these cacti. Cell lines of extracts with cytotoxicity against glioblastoma cells U87, neuroblastoma cells SH-S5Y5, and Schwann neuronal cells (healthy control) were evaluated, using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazole bromide (MTT) reduction technique. The selective cytotoxicity extracts were analyzed using liquid chromatography tandem mass spectrometry (LC/MS²). We isolated 19 endophytic and soil-associated microorganisms from both cacti. Two of them were selected for their high percentages of tumor growth inhibition. The microorganism ES4 possessed the best activity with an IC₅₀ of 17.31 ± 1.70 µg/mL and a selectivity index of 3.11. We identified the bacterium Stenotrophomonas maltophilia by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) from the most active microorganisms against tumor growth. LC/MS² characterized the HS4 extract, and the most abundant group (50.0%) identified included carboxylic acids and derivatives, particularly bisgerayafolin A, Cyclo (Pro-Leu), maculosin, and tryptophan. In conclusion S. maltophilia extract inhibit the growth of glioma cells, showing greater sensitivity in the U87 cell line.

Red blood cells represent a widely used cellular model in cytotoxicity studies, particularly in hemocompatibility assessments. As enucleated cells, which are abundant and easily accessible in both humans and animals, red blood cells allow for rapid, reproducible, and low-cost evaluation of the toxicity of bioactive compounds, whether natural, synthetic, or nanoparticulate. From a functional perspective, the red blood cell membrane is highly sensitive to physical and chemical environmental changes (osmolarity, temperature, pH, and the presence of oxidizing agents). This sensitivity makes red blood cells an effective biosensor for detecting membrane damage, hemolysis, oxidative stress, methemoglobin formation, and aggregation processes. Therefore, in vitro tests using red blood cells allow for the preliminary evaluation in preclinical development, particularly for the early screening of cytotoxicity, membrane-disruptive effects, and hemocompatibility of small molecules, nanomaterials, and blood-contacting biomaterials. These techniques include hemocompatibility tests, evaluation of oxidative and osmotic damage, and evaluation of erythrocyte aggregation and function. However, the use of red blood cells as a cytotoxicity model also has significant limitations. As anucleate cells, erythrocytes lack organelles such as nuclei, mitochondria, or lysosomes, which prevents the evaluation of their effects on key intracellular processes such as protein synthesis, cell signaling, apoptosis, or endoplasmic reticulum stress. This lack of cellular complexity limits their usefulness as a sole model in studies of systemic toxicity or tissue-specific cytotoxicity. These tools offer an effective preliminary approach to anticipating risks in biomedical and pharmacological research.