Laboratorio de Biología Celular y Productos Naturales, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional, Guillermo Massieu Helguera 239, Col. La Escalera, Del. Gustavo A. Madero, 07320 CDMX, Mexico.
Laboratorio de Virus y Cáncer, Instituto Nacional de Cancerología, Secretaría de Salud, Av. San Fernando 22, Col. Sección XVI, Del. Tlalpan, 14080 CDMX, Mexico.
J Ethnopharmacol. 2018 Aug 10;222:133-147. doi: 10.1016/j.jep.2018.04.038. Epub 2018 May 3.
Kalanchoe flammea Stapf (Crassulaceae) is a medicinal plant grown in the South of Mexico (State of Tabasco), which is commonly used in traditional medicine for the treatment of fever, wounds, inflammation, and cancer.
To establish the potential of K. flammea for the treatment of prostate cancer, evaluating its cytotoxic activity, its probable mechanism of action, and carrying out some toxicological safety studies.
The cytotoxic activity of the ethyl acetate extract of K. flammea (Kf-EtOAc) was evaluated in several cell lines of prostate cancer by MTT viability assay. The cellular death mechanism was studied by evaluating the translocation of phosphatidylserine (Annexin V); overproduction of reactive oxygen species [2'-7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) assay]; release of Cytochrome C; activation of caspase-3 and -9, and regulation of Bcl-2, XIAP, and PKCε proteins by Western Blot analysis. For the evaluation of the safety of Kf-EtOAc, the Ames test, Micronucleus assay, and acute toxicity study were determined.
Kf-EtOAc exhibited selective cytotoxic activity against prostate cell lines as follows: PC-3, LNCaP, and PrEC (IC = 1.36 ± 0.05; 2.06 ± 0.02, and 127.05 ± 0.07 μg/mL, respectively). The F82-P2 fraction (rich in coumaric acid and palmitic acid) obtained by bioassay-guided fractionation of Kf-EtOAc also demonstrated selective cytotoxic activity against PC-3 cells (IC = 1.05 ± 0.06 μg/mL). Kf-EtOAc induces apoptosis by the intrinsic pathway; this mechanism of cell death was confirmed after observing that the extract produces phosphatidylserine translocation, overproduction of reactive oxygen species, release of Cytochrome C at mitochondrial level, and activation of caspase-3 and -9. It was also observed that Kf-EtOAc produces significant downregulation of apoptosis-related proteins Bcl-2, XIAP, and PKCε and induces DNA fragmentation and cell cycle arrest. In addition, Kf-EtOAc is non-genotoxic in vitro by Ames test and non-genotoxic in vivo by Micronucleus assay, and no signs of toxicity or death were reported after the administration of a single acute exposure of 2000 mg/kg.
K. flammea is a potential candidate for the development of new drugs for the treatment of prostate cancer. However, to propose their use in clinical trials, additional studies are required to understand their pharmacokinetic behavior, as well as the development of a suitable pharmaceutical form.
Kalanchoe flammea Stapf（景天科）是一种生长在墨西哥南部（塔巴斯科州）的药用植物，在传统医学中常用于治疗发热、伤口、炎症和癌症。
评估 K. flammea 治疗前列腺癌的潜力，评估其细胞毒性活性、可能的作用机制，并进行一些毒理学安全性研究。
通过 MTT 活力测定法评估 K. flammea（Kf-EtOAc）的乙酸乙酯提取物对几种前列腺癌细胞系的细胞毒性活性。通过评估磷脂酰丝氨酸（Annexin V）的易位；活性氧（2'-7'-二氯二氢荧光素二乙酸酯（DCFH-DA）测定法）的过度产生；细胞色素 C 的释放；caspase-3 和-9 的激活以及通过 Western Blot 分析调节 Bcl-2、XIAP 和 PKCε 蛋白来研究细胞死亡机制。为了评估 Kf-EtOAc 的安全性，进行了 Ames 试验、微核试验和急性毒性研究。
Kf-EtOAc 对前列腺细胞系 PC-3、LNCaP 和 PrEC 表现出选择性细胞毒性活性（IC=1.36±0.05；2.06±0.02 和 127.05±0.07μg/mL）。通过 Kf-EtOAc 的生物测定指导的分段，获得的 F82-P2 级分（富含咖啡酸和棕榈酸）也对 PC-3 细胞表现出选择性细胞毒性活性（IC=1.05±0.06μg/mL）。Kf-EtOAc 通过内在途径诱导细胞凋亡；在用提取物产生磷脂酰丝氨酸易位、活性氧过度产生、线粒体水平细胞色素 C 释放和 caspase-3 和-9 激活来证实这种细胞死亡机制后，观察到这种情况。还观察到 Kf-EtOAc 导致凋亡相关蛋白 Bcl-2、XIAP 和 PKCε 的显着下调，并诱导 DNA 片段化和细胞周期停滞。此外，Kf-EtOAc 在体外通过 Ames 试验是非致突变的，在体内通过微核试验是非致突变的，并且在单次急性暴露 2000mg/kg 后没有报告毒性或死亡迹象。
K. flammea 是开发用于治疗前列腺癌的新药的潜在候选药物。然而，为了提出在临床试验中使用它们，需要进一步研究以了解它们的药代动力学行为，以及合适的药物形式的开发。
