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CCR4:Treg細(xì)胞上的關(guān)鍵趨化因子受體,有望成為新型腫瘤免疫治療靶點(diǎn)!

日期:2022-02-17 10:58:06

2022年1月7日,Nature Reviews Clinical Oncology(IF: 66.675)雜志上發(fā)表了一篇題為“Harnessing cytokines and chemokines for cancer therapy”的綜述 [1]。在本文中,作者談到了趨化因子受體阻斷的臨床試驗(yàn)用于治療惡性腫瘤的巨大潛力。同樣引起關(guān)注的是,CCR4作為關(guān)鍵的腫瘤相關(guān)的趨化因子受體,在一項涉及實(shí)體腫瘤患者的I期試驗(yàn)中,研究人員發(fā)現(xiàn),采用抗CCR4單抗可顯著減少腫瘤內(nèi)Treg細(xì)胞數(shù)量,從而改善Treg細(xì)胞誘導(dǎo)的腫瘤免疫抑制 [1]。CCR4作為新興的潛力靶點(diǎn),已有一款CCR4拮抗劑用于治療血液瘤T細(xì)胞淋巴瘤。近年來,多項研究數(shù)據(jù)表明,CCR4在更多實(shí)體瘤等疾病中扮演重要角色。那么,趨化因子受體CCR4如何參與到腫瘤免疫調(diào)控?為何CCR4擁有巨大的靶向治療潛力?

什么是CCR4?

C-C趨化因子受體(C-C chemokine receptor type 4,CCR4),也稱為CD194,由包含7次跨膜結(jié)構(gòu)域的多肽鏈組成,屬于G蛋白偶聯(lián)受體家族。其含360個氨基酸,分子量約為41kD,主要表達(dá)于各種淋巴細(xì)胞和組織,其配體包括多種趨化因子 [2]。作為重要的趨化因子受體,CCR4與其它趨化因子配體產(chǎn)生結(jié)合,行使其功能,參與調(diào)控人類自身免疫疾病過程,主要包括特應(yīng)性皮炎、哮喘、皮膚T細(xì)胞淋巴瘤 [3]。過去,研究人員對趨化因子的認(rèn)識限于在炎癥反應(yīng)中的趨化作用,然而越來越多的研究顯示,趨化因子結(jié)合其受體在腫瘤細(xì)胞的浸潤性生長,遠(yuǎn)處轉(zhuǎn)移等行為中發(fā)揮重要作用。CCR4作為腫瘤轉(zhuǎn)移中關(guān)鍵的趨化因子受體,多項研究已證實(shí),CCR4高表達(dá)與血液系統(tǒng)腫瘤以及惡性實(shí)體瘤的浸潤和預(yù)后密切相關(guān),靶向CCR4有望成為惡性腫瘤免疫治療的新策略。

CCR4的配體有哪些?

CCR4已知的配體有CCL17、CCL22、RANTES、MCP-1、MIP-1α和最新配體CKLF1,但也可能存在更多的趨化因子配體 [1-3, 5]。目前的研究集中在CCR4和高親和力配體CCL17以及CCL22之間的互相作用。CCL17又稱胸腺活化調(diào)節(jié)趨化因子(TARC),主要在胸腺中表達(dá),也表達(dá)于其他組織如肺、結(jié)腸、小腸等。該趨化因子與CCR4特異性結(jié)合,誘導(dǎo)T細(xì)胞的趨化作用。CCL22又稱巨噬細(xì)胞源趨化因子(MDC),主要由樹突狀細(xì)胞和巨噬細(xì)胞分泌產(chǎn)生,通過與細(xì)胞表面受體CCR4結(jié)合,對T淋巴細(xì)胞、B淋巴細(xì)胞和樹突狀細(xì)胞的分化、發(fā)育、增殖起重要的調(diào)控作用。近年來,CCL17和CCL22作為CCR4的高親和力受體,兩者同CCR4結(jié)合不僅在多種炎癥性疾病中發(fā)揮重要作用,而且與多種惡性腫瘤的生物學(xué)行為和轉(zhuǎn)移機(jī)制密切相關(guān) [6]。

CCR4介導(dǎo)的信號通路機(jī)制

CCL17和CCL22作為CCR4最常見的特異性配體,越來越多的研究表明了它們在免疫應(yīng)答中的作用,尤其在腫瘤細(xì)胞中的作用。但是,趨化因子及其受體在腫瘤的形成和發(fā)展中產(chǎn)生的作用是復(fù)雜而精細(xì)的,它們是如何激活某些信號轉(zhuǎn)導(dǎo)途徑的機(jī)制尚未研究清楚。

目前的研究認(rèn)為,CCR4結(jié)合CCL17/CCL22可誘導(dǎo)Treg細(xì)胞在腫瘤細(xì)胞周圍的微環(huán)境里富集。Treg細(xì)胞是T細(xì)胞的一種,對免疫反應(yīng)可產(chǎn)生抑制的作用。這種抑制作用能夠有效地避免自體免疫反應(yīng)的發(fā)生。腫瘤細(xì)胞正是利用這些Treg細(xì)胞來擺脫免疫系統(tǒng)的威脅(點(diǎn)擊了解更多Treg細(xì)胞)。如圖1,CCR4通過CCR4+Treg細(xì)胞發(fā)揮免疫效應(yīng),參與到不同腫瘤細(xì)胞的侵襲轉(zhuǎn)移,淋巴細(xì)胞生成以及淋巴細(xì)胞的呈遞作用,腫瘤炎癥介質(zhì)的產(chǎn)生等等 [7],其原因是Treg細(xì)胞表面的CCR4通過與其趨化因子配體結(jié)合,從而趨化Treg細(xì)胞,引起腫瘤免疫逃逸,其機(jī)制作用類似Treg細(xì)胞特異性靶點(diǎn)CCR8(點(diǎn)擊查看CCR8相關(guān)文章)。

CCR4結(jié)合CCL17/CCL22誘導(dǎo)Treg細(xì)胞腫瘤免疫抑制

圖1. CCR4結(jié)合CCL17/CCL22誘導(dǎo)Treg細(xì)胞腫瘤免疫抑制

CCR4在癌癥等疾病中的作用

CCR4作為一個逐漸被認(rèn)識的趨化因子受體,越來越多的研究表明,CCR4與趨化因子CCL17/CCL22結(jié)合,參與到體內(nèi)許多重要的生理和病理效應(yīng),并與過敏性炎癥疾?。ㄌ貞?yīng)性皮炎)、自身免疫性疾?。愶L(fēng)濕性關(guān)節(jié)炎)以及多種腫瘤(T細(xì)胞淋巴瘤、乳腺癌、肺癌和胃癌等等)相關(guān) [8]。

CCR4和過敏性炎癥疾病

近期,一款CCR4抑制劑RPT193在治療特應(yīng)性皮炎(Allergic Dermatitis,AD)中取得突破,其臨床研究表明,RPT193具有良好的耐受性和安全性,對重度特應(yīng)性皮炎患者的療效顯著。相關(guān)研究進(jìn)一步揭示,RPT193治療優(yōu)于IL-4R抗體治療。RPT193可通過阻斷Th2細(xì)胞上高表達(dá)的CCR4受體,選擇性抑制Th2細(xì)胞向炎癥組織的遷移,在特應(yīng)性皮炎和哮喘疾病中發(fā)揮作用 [9]。明確的療效信號預(yù)示著RPT193巨大臨床潛力,同時也說明CCR4靶點(diǎn)在過敏性炎癥疾病中的巨大研究前景。

CCR4和自身免疫性疾病

有數(shù)據(jù)表明,在類風(fēng)濕關(guān)節(jié)炎(Rheumatoid Arthritis, RA)和系統(tǒng)性紅斑狼瘡(Systemic Lupus Erythematosus,SLE)患者外周血中,Treg細(xì)胞上趨化因子受體CCR4表達(dá)明顯增加,且CCR4表達(dá)異常與疾病的進(jìn)展有相關(guān)性。其原因可能是CCR4受體反應(yīng)性增多,Tregs細(xì)胞獲得定向遷移至致病關(guān)節(jié)的能力,從而促進(jìn)其向炎癥部位移動,發(fā)揮免疫抑制作用 [10]。因此,進(jìn)一步的探索RA和SLE患者的Treg細(xì)胞變化與趨化因子受體CCR4表達(dá)關(guān)系,將對患者的發(fā)病機(jī)制具有臨床指導(dǎo)意義。

CCR4和腫瘤疾病

最早對于CCR4和惡性腫瘤關(guān)系的研究主要是針對成人T細(xì)胞性白血病/淋巴瘤等血液系統(tǒng)腫瘤的研究 [11]。目前已有的研究證實(shí),CCR4表達(dá)還與乳腺癌 [12]、肺癌 [13]、胃癌 [14]、胰腺癌 [15]、肝癌 [16]、結(jié)腸直腸癌 [17]等多種惡性腫瘤相關(guān)。

在血液瘤以及其它惡性腫瘤中,CCR4主要是通過同配體CCL17和CCL22的結(jié)合趨化Treg細(xì)胞聚集引起免疫逃逸,導(dǎo)致不良臨床后果。比如,在T細(xì)胞性白血病患者中,由腫瘤細(xì)胞分泌的CCL17和CCL22創(chuàng)造了腫瘤免疫逃逸的微環(huán)境,趨化了CCR4+Treg細(xì)胞的聚集 [11]。類似的,在乳腺癌中,CCR4/CCL22誘導(dǎo)Treg細(xì)胞遷移到腫瘤周圍的淋巴浸潤組織中,促進(jìn)Treg細(xì)胞表達(dá),促進(jìn)腫瘤生長 [12]。Treg細(xì)胞數(shù)量的異常升高往往與腫瘤患者較差的預(yù)后密切相關(guān)。而CCR4表達(dá)于Treg細(xì)胞,通過同配體CCL17和CCL22的結(jié)合,可以特異性的趨化Treg細(xì)胞的聚集和浸潤,影響腫瘤生物學(xué)行為。因此,CCR4作為Treg細(xì)胞的表面標(biāo)志,通過與其配體的結(jié)合,在腫瘤免疫逃逸機(jī)制尤其是腫瘤轉(zhuǎn)移中可能發(fā)揮重要作用。深入開展CCR4-CCL17/CCL22生物軸的研究有望為惡性腫瘤的靶向治療開辟新的途徑。

靶向CCR4的臨床應(yīng)用前景

CCR4是Treg上占據(jù)支配地位的趨化因子受體。CCR4的生物標(biāo)志與治療潛力正在為腫瘤等疾病的臨床研究提供新的方向。值得一提的是,早在2018年,RAPT Therapeutics公司的首款靶向CCR4單克隆抗體藥物Mogamulizumab獲FDA批準(zhǔn)上市,用于治療罕見皮膚病-皮膚T細(xì)胞淋巴瘤(CTCL)亞型,蕈樣肉芽腫(MF)或Sézary綜合征(SS)。此外,該公司還有兩款在研CCR4抑制劑,分別是用于腫瘤治療的FLX475和用于特應(yīng)性皮炎治療的RPT193。而來自Therapeutic antibody database數(shù)據(jù)顯示,CCR4已有多款在研抗體藥物處于臨床前階段,但尚未公布具體的藥物臨床信息。近年來,CCR4在過敏性疾病、自身免疫性疾病,尤其在腫瘤研究中越來越受到重視,因其在Treg細(xì)胞行使Treg細(xì)胞腫瘤免疫抑制調(diào)控功能中扮演重要角色,這些研究的發(fā)現(xiàn),提示CCR4或可成為腫瘤免疫靶向治療的新靶點(diǎn)。

為鼎力協(xié)助各藥企針對CCR4在過敏性疾病、自身免疫性疾病,尤其在腫瘤臨床中的研究,CUSABIO推出CCR4活性蛋白產(chǎn)品(Code: CSB-MP004843HU; Code: CSB-CF004843HU),助力您在CCR4機(jī)制方面的研究或其潛在臨床價值的探索。

Recombinant Human C-C chemokine receptor type 4 (CCR4)-VLPs (Active)

High Specificity Validated by Western Blot (WB)

CSB-MP004843HU is detected by Mouse anti-6*His monoclonal antibody.

Excellent Bioactivity Validated by Functional ELISA

Immobilized Human CCR4 at 10 μg/ml can bind Anti-CCR4 recombinant antibody (CSB-RA004843MA01HU), the EC50 is 362.3-630.8 ng/mL.

Correct Structure Validated by TEM

The presence of VLP-like structures was confirmed by TEM.

Recombinant Human C-C chemokine receptor type 4 (CCR4) (Active)

High Purity Validated by SDS-PAGE

Purity was greater than 85% as determined by SDS-PAGE. (Tris-Glycine gel) Discontinuous SDS-PAGE (reduced) with 5% enrichment gel and 15% separation gel.

Excellent Bioactivity Validated by Functional ELISA

CCR4 at 5 μg/ml can bind Anti-CCR4 recombinant antibody (CSB-RA004843MA01HU), the EC50 is 7.818-21.25 ng/mL.

參考文獻(xiàn):

[1] Propper, David J., and Frances R. Balkwill. "Harnessing cytokines and chemokines for cancer therapy." Nature Reviews Clinical Oncology (2022): 1-17.

[2] Fujii, Keiichiro, et al. "Immunohistochemistry for CCR4 C‐terminus predicts CCR4 mutations and mogamulizumab efficacy in adult T‐cell leukemia/lymphoma." The Journal of Pathology: Clinical Research 7.1 (2021): 52-60.

[3] Yoshie, Osamu, and Kouji Matsushima. "CCR4 and its ligands: from bench to bedside." International immunology 27.1 (2015): 11-20.

[4] Oliveira, S. H. P., and N. W. Lukacs. "The role of chemokines and chemokine receptors in eosinophil activation during inflammatory allergic reactions." Brazilian Journal of Medical and Biological Research 36.11 (2003): 1455-1463.

[5] Ai, Q. D., et al. "IMM-H004 therapy for permanent focal ischemic cerebral injury via CKLF1/CCR4-mediated NLRP3 inflammasome activation." Translational Research 212 (2019): 36-53.

[6] Kumai, Takumi, et al. "CCL17 and CCL22/CCR4 signaling is a strong candidate for novel targeted therapy against nasal natural killer/T-cell lymphoma." Cancer Immunology, Immunotherapy 64.6 (2015): 697-705.

[7] Ketcham, John M., Lisa A. Marshall, and Oezcan Talay. "CCR4 antagonists inhibit Treg trafficking into the tumor microenvironment." ACS Medicinal Chemistry Letters 9.10 (2018): 953-955.

[8] Solari, Roberto, and James E. Pease. "Targeting chemokine receptors in disease–a case study of CCR4." European Journal of Pharmacology 763 (2015): 169-177.

[9] Cheng, Laurence, et al. "Development and first-in-human characterization of a potent oral CCR4 antagonist for the treatment of atopic dermatitis." Journal of Investigative Dermatology. Vol. 140. No. 7. STE 800, 230 PARK AVE, NEW YORK, NY 10169 USA: ELSEVIER SCIENCE INC, 2020.

[10] Flytlie, Helene Aarslev, et al. "Expression of MDC/CCL22 and its receptor CCR4 in rheumatoid arthritis, psoriatic arthritis and osteoarthritis." Cytokine 49.1 (2010): 24-29.

[11] Ishida, Takashi, et al. "Clinical significance of CCR4 expression in adult T-cell leukemia/lymphoma: its close association with skin involvement and unfavorable outcome." Clinical Cancer Research 9.10 (2003): 3625-3634.

[12] Olkhanud, Purevdorj B., et al. "Breast cancer lung metastasis requires expression of chemokine receptor CCR4 and regulatory T cells." Cancer research 69.14 (2009): 5996-6004.

[13] Kurose, Koji, et al. "Increase in activated Treg in TIL in lung cancer and in vitro depletion of Treg by ADCC using an antihuman CCR4 mAb (KM2760)." Journal of Thoracic Oncology 10.1 (2015): 74-83.

[14] Lee, Jun Ho, et al. "The chemokine receptor CCR4 is expressed and associated with a poor prognosis in patients with gastric cancer." Annals of surgery 249.6 (2009): 933-941.

[15] Moritz, Rapp, et al. "ITOC2–025. Transduction with CC-chemokine receptor type 4 (CCR4) enhances tumour-specific migration of adoptively transferred T cells in a model of pancreatic cancer." European Journal of Cancer 51 (2015): S9.

[16] Takahashi, Akinori, et al. "The CCR4–NOT complex maintains liver homeostasis through mRNA deadenylation." Life science alliance 3.5 (2020).

[17] Ou, Baochi, et al. "CCR4 promotes metastasis via ERK/NF-κB/MMP13 pathway and acts downstream of TNF-α in colorectal cancer." Oncotarget 7.30 (2016): 47637.

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