Laura Rojas

The analysis of tumor metabolism offers promising opportunities for developing new therapeutic strategies. Plant-derived polymolecular drugs can regulate cellular metabolism, making them potential candidates for treatment. This study examined the metabolic effects of plant-derived polymolecular drugs—P2Et, Anamu-SC, and Esperanza—on leukemic cell lines (lymphoid and myeloid types) and primary leukemic blasts. The metabolic analysis included oxidative status, glucose consumption, extracellular acidification, oxygen consumption, mitochondrial dynamics, and untargeted metabolomics. Additionally, the effect of co-treatment with conventional chemotherapeutic drugs was investigated. Results showed that P2Et and Anamu-SC reduced the viability and proliferation of all tumor cell lines, exhibiting antioxidant effects. Anamu-SC decreased reactive oxygen species levels in lymphoid tumor cells. Mitochondrial activity was selectively affected by the plant-derived polymolecular drugs, with Anamu-SC and Esperanza causing more significant, potentially reversible damage compared to P2Et. Anamu-SC and Esperanza increased levels of phosphatidylcholines and carnitines. The co-administration of plant-derived polymolecular drugs with chemotherapeutics improved the cytostatic efficacy of cytarabine. In conclusion, this research highlights the promising pharmacological activity of Anamu-SC and Esperanza as mitocans for the treatment of acute leukemia. The study emphasizes the practical significance of combining plant-derived polymolecular drugs with conventional chemotherapeutics to enhance their cytostatic efficacy.

Colorectal cancer (CRC) is a prevalent and deadly tumor worldwide. Understanding the molecular mechanisms underlying CRC development will improve treatment outcomes and patient survival. Natural molecules and metabolites from plants, such as Tillandsia usneoides, reduce tumor growth by modulating glucose metabolism and increasing reactive oxygen species (ROS). To shed light on the mechanism involved in the anti-tumor effects of T. usneoides, we evaluated the cytotoxic effect of the ethanolic extract of this plant on the colon cancer cell line SW480 through the activation of the peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear receptor that plays a role on lipid metabolism and inflammation in cancer cells. To this end, we assessed the activation of PPARγ by T. usneoides extract in transactivation luciferase assays, as well as the cytotoxic effect of this extract on the SW480 cell line after knocking down PPARγ using shRNA. Our findings indicate that the T. usneoides extract exhibits cytotoxic effects on the SW480 cell line, potentially in the same way as PPARγ activator, pioglitazone, i.e., by increasing reactive oxygen species (ROS). In addition, both T. usneoides extract and pioglitazone exert lipogenic properties in the SW480 cells. Taken together, these results demonstrate that the T. usneoides extract decreases the viability of the colon cancer cell line SW480, at least in part, through the activation of PPARγ. This suggests the potential for further use of this plant in the treatment of other chronic diseases.

Previously, studies have shown that leukemic cells exhibit elevated glycolytic metabolism and oxidative phosphorylation in comparison to hematopoietic stem cells. These metabolic processes play a crucial role in the growth and survival of leukemic cells. Due to the metabolic plasticity of tumor cells, the use of natural products has been proposed as a therapeutic alternative due to their ability to attack several targets in tumor cells, including those that could modulate metabolism. In this study, the potential of Petiveria alliacea to modulate the metabolism of K562 cell lysates was evaluated by non-targeted metabolomics. Initially, in vitro findings showed that P. alliacea reduces K562 cell proliferation; subsequently, alterations were observed in the endometabolome of cell lysates treated with the extract, mainly in glycolytic, phosphorylative, lipid, and amino acid metabolism. Finally, in vitro assays were performed, confirming that P. Alliacea extract decreased the oxygen consumption rate and intracellular ATP. These results suggest that the anti-tumor activity of the aqueous extract on the K562 cell line is attributed to the decrease in metabolites related to cell proliferation and/or growth, such as nucleotides and nucleosides, leading to cell cycle arrest. Our results provide a preliminary part of the mechanism for the anti-tumor and antiproliferative effects of P. alliacea on cancer.

Natural products obtained from Petiveria alliacea (Anamu-SC) and Caesalpinia spinosa (P2Et) have been used for cancer treatment, but the mechanisms by which they exert their antitumor activity appear to be different. In the present work, we show that the Anamu-SC extract reduces tumor growth in the 4T1 murine mammary carcinoma model but not in the B16-F10 melanoma model, unlike the standardized P2Et extract. Both extracts decreased the levels of interleukin-10 (IL-10) in the B16-F10 model, but only P2Et increased the levels of tumor necrosis factor alpha (TNFα) and interferon gamma (IFNγ). Likewise, co-treatment of P2Et and doxorubicin (Dox) significantly reduced tumor size by 70% compared to the control group, but co-treatment of Anamu-SC with Dox had no additive effect. Analysis of intratumoral immune infiltrates showed that Anamu-SC decreased CD4+ T cell frequency more than P2Et but increased CD8+ T cell frequency more significantly. Both extracts reduced intratumoral monocytic myeloid-derived suppressor-like cell (M-MDSC-LC) migration, but the effect was lost when co-treated with doxorubicin. The use of P2Et alone or in co-treatment with Anamu-SC reduced the frequency of regulatory T cells and increased the CD8+/Treg ratio. In addition, Anamu-SC reduced glucose consumption in tumor cells, but this apparently has no effect on IFNγ- and TNFα-producing T cells, although it did reduce the frequency of IL-2-producing T cells. The efficacy of these herbal preparations is increasingly clear, as is the specificity conditioned by tumor heterogeneity as well as the different chemical complexity of each preparation. Although these results contribute to the understanding of specificity and its future benefits, they also underline the fact that the development of each of these standardized extracts called polymolecular drugs must follow a rigorous path to elucidate their biological activity.

The poor response, adverse effects and drug resistance to treatment of acute myeloid leukemia (AML) have led to searching for safer and more effective therapeutic alternatives. We previously demonstrated that the alcoholic extract of Petiveria alliacea (Esperanza) has a significant in vitro antitumor effect on other tumor cells and also the ability to regulate energy metabolism. We evaluated the effect of the Esperanza extract in vitro and in vivo in a murine model of AML with DA-3/ER-GM cells. First, a chemical characterization of the extract was conducted through liquid and gas chromatography coupled with mass spectrometry. In vitro findings showed that the extract modulates tumor metabolism by decreasing glucose uptake and increasing reactive oxygen species, which leads to a reduction in cell proliferation. Then, to evaluate the effect of the extract in vivo, we standardized the mouse model by injecting DA-3/ER-GM cells intravenously. The animals treated with the extract showed a lower percentage of circulating blasts, higher values of hemoglobin, hematocrit, and platelets, less infiltration of blasts in the spleen, and greater production of cytokines compared to the control group. These results suggest that the antitumor activity of this extract on DA-3/ER-GM cells can be attributed to the decrease in glycolytic metabolism, its activity as a mitocan, and the possible immunomodulatory effect by reducing tumor proliferation and metastasis.

P2Et is the standardized extract of Caesalpinia spinosa (C. spinosa), which has shown the ability to reduce primary tumors and metastasis in animal models of cancer, by mechanisms involving the increase in intracellular Ca++, reticulum stress, induction of autophagy, and subsequent activation of the immune system. Although P2Et has been shown to be safe in healthy individuals, the biological activity and bioavailability can be increased by improving the dosage form. This study investigates the potential of a casein nanoparticle for oral administration of P2Et and its impact on treatment efficacy in a mouse model of breast cancer with orthotopically transplanted 4T1 cells. Animals were treated with either free or encapsulated oral P2Et orally or i.p. Tumor growth and macrometastases were evaluated. All P2Et treatments significantly delayed tumor growth. The frequency of macrometastasis was reduced by 1.1 times with P2Et i.p., while oral P2Et reduced it by 3.2 times and nanoencapsulation reduced it by 3.57 times. This suggests that nanoencapsulation led to higher doses of effective P2Et being delivered, slightly improving bioavailability and biological activity. Therefore, the results of this study provide evidence to consider P2Et as a potential adjuvant in the treatment of cancer, while the nanoencapsulation of P2Et provides a novel perspective on the delivery of these functional ingredients.

The main limits of current antitumor therapies are chemoresistance, relapses, and toxicity that impair patient quality of life. Therefore, the discovery of therapeutic alternatives, such as adjuvants to conventional therapy that modulate the intracellular oxidation state or the immune response, remains a challenge. Owing to traditional medicine, several uses of plants are known, indicating a promising antitumor and immunomodulatory effect. We evaluated the effect of ethanolic extract of T. usneoides in vitro and in vivo in models of 4T1 breast cancer and B16-F10 melanoma. In vitro evaluations with both cell lines showed that the extract has cytotoxic activity and induces apoptotic cell death. However, its effect on ROS production and glucose uptake was opposite. In vivo, only in the 4T1 model, a significant decrease in tumor size was found in animals treated with the extract, accompanied by an increase in dendritic cells and activated CD8⁺ T cells, and a decrease in myeloid-derived suppressor-like cells (MDSC-LC) and Tregs in the tumor microenvironment. These results suggest that T. usneoides extract antagonistically regulates tumor metabolism of 4T1 vs. B16-F10, impacting the tumor microenvironment and effective antitumor immune response, leading to a reduction in 4T1 tumor size but not on B16-F10.

Previous studies revealed the potential of Labrenzia aggregata USBA 371 to produce cytotoxic metabolites. This study explores its metabolic diversity and compounds involved in its cytotoxic activity. Extracts from the extracellular fraction of strain USBA 371 showed high levels of cytotoxic activity associated with the production of diketopiperazines (DKPs). We purified two compounds and a mixture of two other compounds from this fraction. Their structures were characterized by 1D and 2D nuclear magnetic resonance (NMR). The purified compounds were evaluated for additional cytotoxic activities. Compound 1 (cyclo (l-Pro-l-Tyr)) showed cytotoxicity to the following cancer cell lines: breast cancer 4T1 (IC₅₀ 57.09 ± 2.11 µM), 4T1H17 (IC₅₀ 40.38 ± 1.94), MCF-7 (IC₅₀ 87.74 ± 2.32 µM), murine melanoma B16 (IC₅₀ 80.87 ± 3.67), human uterus sarcoma MES-SA/Dx5 P-pg (−) (IC₅₀ 291.32 ± 5.64) and MES-SA/Dx5 P-pg (+) (IC₅₀ 225.28 ± 1.23), and murine colon MCA 38 (IC₅₀ 29.85 ± 1.55). In order to elucidate the biosynthetic route of the production of DKPs and other secondary metabolites, we sequenced the genome of L. aggregata USBA 371. We found no evidence for biosynthetic pathways associated with cyclodipeptide synthases (CDPSs) or non-ribosomal peptides (NRPS), but based on proteogenomic analysis we suggest that they are produced by proteolytic enzymes. This is the first report in which the cytotoxic effect of cyclo (l-Pro-l-Tyr) produced by an organism of the genus Labrenzia has been evaluated against several cancer cell lines.

In order to select halophilic microorganisms as a source of compounds with cytotoxic activities, a total of 135 bacterial strains were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes. We determined the cytotoxic effects of 100 crude extracts from 54 selected organisms on the adherent murine mammary cell carcinoma 4T1 and human mammary adenocarcinoma MCF-7 cell lines. These extracts were obtained from strains of Isoptericola, Ornithinimicrobium, Janibacter, Nesterenkonia, Alkalibacterium, Bacillus, Halomonas, Chromohalobacter, Shewanella, Salipiger, Martellela, Oceanibaculum, Caenispirillum and Labrenzia. The extracts of 23 strains showed an IC50 of less than 100 μg mL−1. They were subsequently analyzed by LC/MS allowing dereplication of 20 compounds. The cytotoxic effect was related to a complex mixture of diketopiperazines present in many of the extracts analyzed. The greatest cytotoxic activity against both of the evaluated cell lines was obtained from the chloroform extract of Labrenzia aggregata USBA 371 which had an IC50 < 6 μg mL−1. Other extracts with high levels of cytotoxic activity were obtained from Bacillus sp. (IC50 < 50 μg mL−1) which contained several compounds such as macrolactin L and A, 7-O-succinoylmacrolactin F and iturin. Shewanella chilikensis USBA 344 also showed high levels of cytotoxic activity against both cell lines in the crude extract: an IC50 < 15 μg mL−1 against the 4T1 cell line and an IC50 < 68 μg mL−1 against the MCF-7 cell line. Nesterenkonia sandarakina CG 35, which has an IC50 of 118 µg mL−1 against 4T1, is a producer of diketopiperazines and 1-acetyl-β-carboline. Also, Ornithinimicrobium kibberense CG 24, which has IC50 < 50 μg mL−1, was a producer of diketopiperazines and lagunamycin. Our study demonstrates that these saline environments are habitats of halophilic and halotolerant bacteria that have previously unreported cytotoxic activity.