近日,，美國(guó)密蘇里大學(xué)的科研人員發(fā)現(xiàn)了一種有效的前列腺癌治療方式，能夠借助放射性納米金和在茶葉內(nèi)發(fā)現(xiàn)的化合物“瞄準(zhǔn)”前列腺腫瘤,，并且不會(huì)損害病患體內(nèi)的健康器官或影響其身體的正常機(jī)能。相關(guān)研究報(bào)告發(fā)表在美國(guó)《國(guó)家科學(xué)院學(xué)報(bào)》（PNAS）上,。
研究中,，科學(xué)家在茶葉中發(fā)現(xiàn)了一種能夠被吸引至前列腺腫瘤細(xì)胞的特殊化合物。當(dāng)將這種化合物與由研究反應(yīng)堆產(chǎn)生的納米金相結(jié)合時(shí),，茶葉內(nèi)的化合物會(huì)幫忙將納米粒子“傳送”到腫瘤的所在區(qū)域,，使得這些治療性的臨床級(jí)放射性同位素能夠有效地破壞腫瘤細(xì)胞。
大多數(shù)時(shí)候,，前列腺癌都發(fā)展得十分緩慢,，但極具侵略性的前列腺癌卻能快速蔓延至身體的其他部分。傳統(tǒng)療法需要將數(shù)百個(gè)放射性“種子”注射進(jìn)前列腺,，但這對(duì)極具侵略性的前列腺癌并無(wú)效果,。“種子”的大小和它們傳送有效劑量的能力受限，都會(huì)影響其對(duì)于前列腺癌的治療,。
而在新療法中,，每個(gè)納米金都大小合適，只需要1次至2次注射,，納米粒子便會(huì)聚集在腫瘤內(nèi)部,，從而有望達(dá)到良好的治療效果。研究人員堅(jiān)信,，放射性納米金能夠同時(shí)縮小緩慢生長(zhǎng)和極具侵略性的前列腺腫瘤,，甚至完全根除它們。這是因?yàn)榧{米金不僅具有適合的尺寸,，還具備很短的半衰期,。其半衰期僅為2.7天，這意味著納米金的放射將在3周內(nèi)結(jié)束,，因此能令納米粒子保持較高的效力,，使得腫瘤的體積能在28天治療后大幅減小,。
目前，研究小組已經(jīng)在小鼠身上進(jìn)行了測(cè)試,，下一步還將在前列腺癌形態(tài)與人類(lèi)十分接近的犬類(lèi)身上進(jìn)行測(cè)試,，并逐步將測(cè)試拓展至大型動(dòng)物和人體。（生物谷Bioon.com）
doi:10.1073/pnas.1121174109
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Laminin receptor specific therapeutic gold nanoparticles (198AuNP-EGCg) show efficacy in treating prostate cancer
Ravi Shukla, Nripen Chanda, Ajit Zambre, Anandhi Upendran, Kavita Katti, Rajesh R. Kulkarni, Satish Kumar Nune, Stan W. Casteele, Charles Jeffrey Smith, Jatin Vimalh, Evan Boote, J. David Robertson, Para Kani, Hendrik Engelbrechtg, Lisa D. Watkinson, Terry L. Carmack, John R. Leverj, Cathy S. Cutler, Charles Caldwell, Raghuraman Kannan, and Kattesh V. Katti
Systemic delivery of therapeutic agents to solid tumors is hindered by vascular and interstitial barriers. We hypothesized that prostate tumor specific epigallocatechin-gallate (EGCg) functionalized radioactive gold nanoparticles, when delivered intratumorally (IT), would circumvent transport barriers, resulting in targeted delivery of therapeutic payloads. The results described herein support our hypothesis. We report the development of inherently therapeutic gold nanoparticles derived from the Au-198 isotope; the range of the 198Au β-particle (approximately 11 mm in tissue or approximately 1100 cell diameters) is sufficiently long to provide cross-fire effects of a radiation dose delivered to cells within the prostate gland and short enough to minimize the radiation dose to critical tissues near the periphery of the capsule. The formulation of biocompatible 198AuNPs utilizes the redox chemistry of prostate tumor specific phytochemical EGCg as it converts gold salt into gold nanoparticles and also selectively binds with excellent affinity to Laminin67R receptors, which are over expressed in prostate tumor cells. Pharmacokinetic studies in PC-3 xenograft SCID mice showed approximately 72% retention of 198AuNP-EGCg in tumors 24 h after intratumoral administration. Therapeutic studies showed 80% reduction of tumor volumes after 28 d demonstrating significant inhibition of tumor growth compared to controls. This innovative nanotechnological approach serves as a basis for designing biocompatible target specific antineoplastic agents. This novel intratumorally injectable 198AuNP-EGCg nanotherapeutic agent may provide significant advances in oncology for use as an effective treatment for prostate and other solid tumors.
