Cancer Care Centre and Prostate Cancer Institute, St George Hospital, Kogarah, Australia; St George and Sutherland Clinical School, University of New South Wales (UNSW), Kensington, Australia.
Prostate. 2014 May;74(6):602-17. doi: 10.1002/pros.22775. Epub 2014 Feb 12.
Prostate cancer (CaP) is the second leading malignancy in older men in Western countries. The role of CD44 variant 6 (CD44v6) in CaP progression and therapeutic resistance is still uncertain. Here, we investigated the roles of CD44v6 in CaP metastasis and chemo/radioresistance. Expression of CD44v6 in metastatic CaP cell lines, human primary CaP tissues and lymph node metastases was assessed using immunofluorescence and immunohistochemistry, respectively.
Knock down (KD) of CD44v6 was performed in PC-3M, DU145, and LNCaP cells using small interfering RNA (siRNA), and confirmed by confocal microscope, Western blot and quantitative real time polymerase chain reaction (qRT-PCR). Cell growth was evaluated by proliferation and colony formation assays. The adhesive ability and invasive potential were assessed using a hyaluronic acid (HA) adhesion and a matrigel chamber assay, respectively. Tumorigenesis potential and chemo-/radiosensitivity were measured by a sphere formation assay and a colony assay, respectively.
Over-expression of CD44v6 was found in primary CaP tissues and lymph node metastases including cancer cells and surrounding stromal cells. KD of CD44v6 suppressed CaP proliferative, invasive and adhesive abilities, reduced sphere formation, enhanced chemo-/radiosensitivity, and down-regulated epithelial-mesenchymal transition (EMT), PI3K/Akt/mTOR, and Wnt/β-catenin signaling pathway proteins in vitro.
Our findings demonstrate that CD44v6 is an important cancer stem cell-like marker associated with CaP proliferation, invasion, adhesion, metastasis, chemo-/radioresistance, and the induction of EMT as well as the activation PI3K/Akt/mTOR and Wnt signaling pathways, suggesting that CD44v6 is a novel therapeutic target to sensitize CaP cells to chemo/radiotherapy.
前列腺癌（CaP）是西方国家老年男性中第二大恶性肿瘤。CD44 变体 6（CD44v6）在 CaP 进展和治疗耐药性中的作用仍不确定。在这里，我们研究了 CD44v6 在 CaP 转移和化疗/放疗耐药中的作用。使用免疫荧光和免疫组织化学分别评估转移性 CaP 细胞系、人原发性 CaP 组织和淋巴结转移中 CD44v6 的表达。
使用小干扰 RNA（siRNA）在 PC-3M、DU145 和 LNCaP 细胞中敲低（KD）CD44v6，并通过共聚焦显微镜、Western blot 和定量实时聚合酶链反应（qRT-PCR）进行确认。通过增殖和集落形成测定评估细胞生长。通过透明质酸（HA）粘附和基质胶室测定分别评估粘附能力和侵袭潜力。通过球体形成测定和集落测定分别测量肿瘤发生潜力和化疗/放疗敏感性。
在原发性 CaP 组织和包括癌细胞和周围基质细胞在内的淋巴结转移中发现 CD44v6 过表达。CD44v6 的 KD 抑制了 CaP 的增殖、侵袭和粘附能力，减少了球体形成，增强了化疗/放疗敏感性，并下调了上皮-间充质转化（EMT）、PI3K/Akt/mTOR 和 Wnt/β-catenin 信号通路蛋白在体外。
我们的研究结果表明，CD44v6 是与 CaP 增殖、侵袭、粘附、转移、化疗/放疗耐药以及 EMT 的诱导以及 PI3K/Akt/mTOR 和 Wnt 信号通路的激活相关的重要癌症干细胞样标志物，提示 CD44v6 是一种新型治疗靶点，可使 CaP 细胞对化疗/放疗敏感。
