Abstract

Polyamine synthesis in human cells is initiated by catalytic action of Ornithine decarboxylase (ODC) on Ornithine. Elevated levels of polyamines are manifested proliferating cancer cells and are found to promote tumour cell adhesion. Di-flouro methyl orninthine is a known inhibitor of ODC, however its usage is limited due its low affinity quick clearance and incompetent cellular uptake, thus posing a need for potential inhibitors. Currently, peptides are substituting drugs, as these are highly selective, specific and potent. Hence, in this study, the interacting interfaces of native homodimeric form of ODC and its heterodimer with Antizyme were probed to design inhibitory peptides targeting ODC. The designed peptides were validated for structural fitness by extensive molecular dynamics simulations and Circular dichroism studies. Finally, these peptides were validated in Y79 retinoblastoma cells for impact on ODC activity, cytotoxicity cell cycle and cell adhesion. On collective analysis, Peptide3 (Pep 3) and Peptide4 (Pep 4) were found to be potentially targeting ODC, as these peptides showed significant decrease in intracellular polyamine levels, cell adhesion and cell cycle perturbation in Y79 cells. Thus, Pep 3 and Pep 4 shall be favourably considered as therapeutic agents for targeting ODC mediated proliferation in retinoblastoma.

Communicated by Ramaswamy H. Sarma

摘要

人细胞中的多胺合成是由鸟氨酸脱羧酶 (ODC) 对鸟氨酸的催化作用引发的。多胺水平升高表明癌细胞增殖，并被发现促进肿瘤细胞粘附。二氟甲基鸟氨酸是一种已知的 ODC 抑制剂，但由于其亲和力低、快速清除和细胞摄取不充分，因此其使用受到限制，因此需要潜在的抑制剂。目前，肽正在替代药物，因为它们具有高度选择性、特异性和效力。因此，在本研究中，探索了 ODC 的天然同源二聚体形式及其异源二聚体与 Antizyme 的相互作用界面，以设计靶向 ODC 的抑制肽。通过广泛的分子动力学模拟和圆二色性研究，对设计的肽的结构适应性进行了验证。最后，这些肽在 Y79 视网膜母细胞瘤细胞中对 ODC 活性、细胞毒性细胞周期和细胞粘附的影响进行了验证。在集体分析中，发现 Peptide3 (Pep 3) 和 Peptide4 (Pep 4) 可能靶向 ODC，因为这些肽在 Y79 细胞中显示出细胞内多胺水平、细胞粘附和细胞周期扰动的显着降低。因此，Pep 3 和 Pep 4 应被有利地视为用于靶向 ODC 介导的视网膜母细胞瘤增殖的治疗剂。Y79 细胞中的细胞粘附和细胞周期扰动。因此，Pep 3 和 Pep 4 应被有利地视为用于靶向 ODC 介导的视网膜母细胞瘤增殖的治疗剂。Y79 细胞中的细胞粘附和细胞周期扰动。因此，Pep 3 和 Pep 4 应被有利地视为用于靶向 ODC 介导的视网膜母细胞瘤增殖的治疗剂。

由 Ramaswamy H. Sarma 交流