日前,，美國(guó)科學(xué)家研制出了一種能幫助人體免疫系統(tǒng)摧毀癌細(xì)胞的新型藥物，對(duì)乳腺癌,、腸癌,、前列腺癌、子宮癌,、腦癌,、膀胱癌、肝癌等多種癌癥都有療效,。此外前期研究表明,，該藥物還可用于治療血癌（白血病）,。研究人員表示,，若能及早使用，該藥物甚至可以完全治愈惡性腫瘤疾病,，且副作用極小,。
目前這種藥物僅在小白鼠身上進(jìn)行了試驗(yàn)，研究人員希望能在兩年內(nèi)開(kāi)始臨床試驗(yàn),。
據(jù)悉,，新型藥物的效力集中于一種大量存在于癌細(xì)胞表面的蛋白質(zhì)，這種名叫“CD47”的蛋白質(zhì)能使癌細(xì)胞免于被叫作“巨噬細(xì)胞”的免疫細(xì)胞所吞噬,。新藥物能去掉癌細(xì)胞這一“不要吞噬我信號(hào)”,，讓免疫系統(tǒng)直接對(duì)惡性腫瘤細(xì)胞展開(kāi)攻擊。
該藥物研究員,，美國(guó)斯坦福大學(xué)醫(yī)學(xué)院博士歐文·韋斯曼表示：“沒(méi)了‘不要吞噬我信號(hào)’,，小白鼠體內(nèi)的幾乎所有種類(lèi)的人類(lèi)癌細(xì)胞都不再增長(zhǎng)，且（新藥物）副作用極小,。我們的研究表明,，‘CD47’確為人類(lèi)戰(zhàn)勝癌癥的關(guān)鍵,。”
韋斯曼博士補(bǔ)充稱(chēng)，當(dāng)新藥物作用于小型腫瘤時(shí)“有治愈的可能”,，但在某些小白鼠身上,，卻沒(méi)有絲毫療效。即便如此韋斯曼博士還是認(rèn)為,，新藥物現(xiàn)已具備臨床試驗(yàn)的條件,，需“快速而慎重地推進(jìn)”。
對(duì)于新藥物安全性的嚴(yán)格要求意味著該藥物的廣泛應(yīng)用可能還需十幾年的時(shí)間,，英國(guó)癌癥研究會(huì)免疫學(xué)專(zhuān)家菲利普·阿什頓·利卡特教授認(rèn)為,，上述研究可能會(huì)創(chuàng)造全新的癌癥療法。“對(duì)傳統(tǒng)化療或放射性治療已產(chǎn)生抵抗力的惡性腫瘤細(xì)胞將有可能通過(guò)這種新藥物得到控制,，但新藥物還需在臨床試驗(yàn)中證明其在人體內(nèi)的效果,。”（生物谷Bioon.com）
doi:10.1073/pnas.1121623109
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The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors
Stephen B. Willingham, Jens-Peter Volkmer, Andrew J. Gentles, Irving L. Weissman et al.
CD47, a “don't eat me” signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies.
