De Kakali, Banerjee Indranil, Sinha Samarendu, Ganguly Shantanu
Infectious Diseases and Immunology Division (Nuclear Medicine Laboratory), CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Kolkata, 700032, West Bengal, India.
Infectious Diseases and Immunology Division (Nuclear Medicine Laboratory), CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Kolkata, 700032, West Bengal, India.
Peptides. 2017 Mar;89:17-34. doi: 10.1016/j.peptides.2017.01.002. Epub 2017 Jan 11.
Increasing evidence of peptide receptor overexpression in various cancer cells, warrant the development of receptor specific radiolabeled peptides for molecular imaging and therapy in nuclear medicine. Gastrin-releasing-peptide (GRP) receptor, are overexpressed in a variety of human cancer cells. The present study report the synthesis and biological evaluation of new bombesin (BBN) analogs, HYNIC-Asp-[Phe]BBN(7-13)-NH-CH-CH-CH3:BA1, HYNIC-Pro-[TyrMet]BBN(7-14)NH:BA2 as prospective tumor imaging agent with compare to BBN(7-14)NH:BS as standard. The pharmacophores were radiolabeled in high yields with Tc, characterized for their stability in serum and saline, cysteine/histidine and were found to be substantially stable. Internalization/externalization and receptor binding studies were assessed using MDA-MB-231 cells and showed high receptor binding-affinity and favourable internalization. Fluorescence studies revealed that BA1 changed the morphology of the cells and could localize in the nucleus more effectively than BA2/BS. Cell-viability studies displayed substantial antagonistic and nuclear-internalization effect of BA1. BA1 also exhibited antiproliferative effect on MDA-MB-231 cell by inducing apoptosis. In vivo behaviour of the radiopeptides was evaluated in GRP receptor positive tumor bearing mice. The Tc-BA1/Tc-BA2 demonstrated rapid blood/urinary clearance through the renal pathway and comparatively more significant tumor uptake image and favourable tumor-to-non-target ratios provided by Tc-BA1. The specificity of the in vivo uptake was confirmed by co-injection with BS. Moreover, Tc-BA1 provided a much clearer tumor image in scintigraphic studies than others. Thus the combination of favourable in vitro and in vivo properties renders BA1 as more potential antagonist bombesin-peptide for targeting GRP-receptor positive tumor. These properties are encouraging to carry out further experiments for non-invasive receptor targeting potential diagnostinc and therapeutic agent for tumors.
越来越多的证据表明各种癌细胞中肽受体过度表达，这为开发用于核医学分子成像和治疗的受体特异性放射性标记肽提供了依据。胃泌素释放肽（GRP）受体在多种人类癌细胞中过度表达。本研究报告了新型蛙皮素（BBN）类似物HYNIC-Asp-[Phe]BBN(7-13)-NH-CH-CH-CH3:BA1、HYNIC-Pro-[TyrMet]BBN(7-14)NH:BA2作为前瞻性肿瘤成像剂的合成及生物学评价，并与标准物BBN(7-14)NH:BS进行了比较。这些药效基团用锝进行了高产率的放射性标记，对其在血清、盐水、半胱氨酸/组氨酸中的稳定性进行了表征，发现它们相当稳定。使用MDA-MB-231细胞评估了内化/外化及受体结合研究，结果显示具有高受体结合亲和力和良好内化效果。荧光研究表明，BA1改变了细胞形态，并且比BA2/BS更有效地定位于细胞核。细胞活力研究显示BA1具有显著的拮抗和核内化作用。BA1还通过诱导凋亡对MDA-MB-231细胞表现出抗增殖作用。在GRP受体阳性荷瘤小鼠中评估了放射性肽的体内行为。Tc-BA1/Tc-BA2通过肾脏途径表现出快速的血液/尿液清除率，Tc-BA1提供了相对更显著的肿瘤摄取图像和良好的肿瘤与非靶组织比值。通过与BS共同注射证实了体内摄取的特异性。此外，在闪烁扫描研究中，Tc-BA1提供的肿瘤图像比其他的更清晰。因此，良好的体外和体内特性使BA1成为更有潜力的靶向GRP受体阳性肿瘤的拮抗型蛙皮素肽。这些特性鼓励开展进一步实验，以研究其作为肿瘤非侵入性受体靶向潜在诊断和治疗剂的潜力。
