Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil; Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Brazil.
Biochem Pharmacol. 2019 Oct;168:38-47. doi: 10.1016/j.bcp.2019.06.016. Epub 2019 Jun 19.
DNA-damaging agents are widely used in cancer therapy; however, their use is limited by dose-related toxicities, as well as the development of drug resistance. Drug discovery is essential to overcome these limitations and offer novel therapeutic options. In a previous study by our research group, pradimicin-IRD-a new polycyclic antibiotic produced by the actinobacteria Amycolatopsis sp.-displayed antimicrobial and potential anticancer activities. In the present study, cytotoxic activity was further confirmed in a panel of five colon cancer, including those with mutation in TP53 and KRAS, the most common ones observed in cancer colon patients. While all tested colon cancer cells were sensitive to pradimicin-IRD treatment with IC in micromolar range, non-tumor fibroblasts were significantly less sensitive (p < 0.05). The cellular and molecular mechanism of action of pradimicin-IRD was then investigated in the colorectal cancer cell line HCT 116. Pradimicin-IRD presented antitumor effects occurring after at least 6 h of exposure. Pradimicin-IRD induced statistically significant DNA damage (γH2AX and p21), apoptosis (PARP1 and caspase 3 cleavage) and cell cycle arrest (reduced Rb phosphorylation, cyclin A and cyclin B expression) markers. In accordance with these results, pradimicin-IRD increased cell populations in the subG and G/G phases of the cell cycle. Additionally, mass spectrometry analysis indicated that pradimicin-IRD interacted with the DNA double strand. In summary, pradimicin-IRD exhibits multiple antineoplastic activities-including DNA damage, cell cycle arrest, reduction of clonal growth and apoptosis-in the HCT 116 cell line. Furthermore, pradimicin-IRD displays a TP53-independent regulation of p21 expression in HCT 116 TP53, HT-29, SW480, and Caco-2 cells. This exploratory study identified novel targets for pradimicin-IRD and provided insights for its potential anticancer activity as a DNA-damaging agent.
DNA 损伤剂广泛应用于癌症治疗；然而，由于剂量相关的毒性以及耐药性的发展，其应用受到限制。药物发现对于克服这些限制并提供新的治疗选择至关重要。在我们研究小组的先前研究中，普拉迪霉素-IRD-一种由放线菌 Amycolatopsis sp. 产生的新型多环抗生素-显示出抗菌和潜在的抗癌活性。在本研究中，我们进一步在包括 TP53 和 KRAS 突变在内的五种结肠癌细胞系中证实了细胞毒性活性，这两种突变是在结肠癌症患者中最常见的。虽然所有测试的结肠癌细胞对普拉迪霉素-IRD 治疗均敏感，IC 值在微摩尔范围内，但非肿瘤成纤维细胞的敏感性显著降低（p<0.05）。然后在结肠癌细胞系 HCT 116 中研究了普拉迪霉素-IRD 的细胞和分子作用机制。普拉迪霉素-IRD 呈现出至少 6 小时暴露后才出现的抗肿瘤作用。普拉迪霉素-IRD 诱导了具有统计学意义的 DNA 损伤（γH2AX 和 p21）、细胞凋亡（PARP1 和 caspase 3 切割）和细胞周期停滞（减少 Rb 磷酸化、cyclin A 和 cyclin B 表达）标志物。与这些结果一致，普拉迪霉素-IRD 增加了细胞周期的 subG 和 G/G 期细胞群体。此外，质谱分析表明普拉迪霉素-IRD 与 DNA 双链相互作用。总之，普拉迪霉素-IRD 在 HCT 116 细胞系中表现出多种抗肿瘤活性，包括 DNA 损伤、细胞周期停滞、克隆生长减少和细胞凋亡。此外，普拉迪霉素-IRD 在 HCT 116、HT-29、SW480 和 Caco-2 细胞中表现出 TP53 非依赖性的 p21 表达调节。这项探索性研究确定了普拉迪霉素-IRD 的新靶标，并为其作为 DNA 损伤剂的潜在抗癌活性提供了见解。
