| 摘要: | 本研究探討玻尿酸合成酶3於癌的保護作用，發現玻尿酸合成酶3在腫瘤周圍的正常乳腺細胞中表現量較高，並驗證玻尿酸合成酶3在腫瘤微環境中的抗癌作用。
本研究證實正常乳腺組織中的玻尿酸合成酶3 mRNA表現量高於腫瘤組織（n = 332，P < 0.0001）。其中玻尿酸合成酶的產物玻尿酸顯著抑制裸鼠中 MDA-MB-231 乳癌細胞株異種移植腫瘤的生長（P = 0.039，每組 n = 5）。相反的，利用玻尿酸合成酶3基因剔除鼠證實，小鼠組織中玻尿酸表現量降低促進了小鼠乳腺癌 (E0771) 細胞同種異體移植腫瘤的生長（P = 0.0086，每組 n = 10）。此外，利用三陰性乳癌患者取得乳癌組織並建立人源化腫瘤異種移植動物實驗證實腫瘤很容易生長於乳腺附近的皮下組織（表示為區域 B），但在乳腺附近皮下組織以外（表示為區域 A）則不易生長。本研究證實從正常乳房組織初代培養之纖維母細胞所分泌的玻尿酸抑制MDA-MB-231 乳癌細胞株細胞遷移（P=0.012）。過度表現玻尿酸合成酶3於乳癌細胞株MDA-MB-231中，細胞內微管乙酰化顯著增加，導致細胞生長周期停滯在 G2/M期並促進自噬細胞死亡。
本研究證實了玻尿酸合成酶3蛋白大量表現於腫瘤組織周圍細胞基質中並具有抗腫瘤遷移作用。本研究利用異種移植動物 (MDA-MB-231)、同種異體移植動物 (E0771) 和 人源化腫瘤異種移植動物(TNBC)，發現玻尿酸合成酶3的產物玻尿酸(50~100 KDa)能有效的抑制腫瘤生長。而過度表現玻尿酸合成酶3於乳癌細胞株中促使微管蛋白過度乙酰化並使細胞週期停滯於G2/M期，誘發線粒體自噬作用和透過自噬作用導致細胞死亡。此研究證實，玻尿酸合成酶3與玻尿酸合成酶3的產物玻尿酸(50~100 KDa)能有效的抑制腫瘤的生長。
This study explored the protective role of type-3 hyaluronan synthase (HAS3), expressed at higher levels in normal breast stroma tissues surrounding tumors, and the antitumor effects of HAS3 in the tumor microenvironment were investigated.
HAS3 mRNA expression levels was higher in normal breast tissue than in tumor tissue (n= 332, P < 0.0001). The HA (1%, w/v) synthesized by HAS significantly inhibited MDA-MB-231 xenograft tumor growth in nude mice (P = 0.039, n = 5 per group). In contrast, decreased HA levels in subcutaneous HAS3-KO mouse tissues promoted mouse breast cancer (E0771) cell allograft tumor growth (P = 0.0086, n = 10 per group). The TNBC-PDX (F4, n=6) tumors were easily established in subcutaneous tissue near the breast (denoted area B) but not in subcutaneous tissues outside area B (denoted area A). Interestingly, increased HAS3 mRNA expression in subcutaneous tissues from area A inhibited TNBC-PDX (F4, n=6) tumor growth (P<0.0001). In vitro studies demonstrated that conditioned medium containing HA from HB-TDFs successfully inhibited MDA-MB-231 cell migration (P=0.012). The antitumor effects of HAS3 protein overexpression in MDA-MB-231 cells were explored, which showed significantly increased intracellular microtubule acetylation resulting in cell growth cycle arrest at G2/M phase and autophagic cell death.
This study demonstrated the anti-migratory effects of HAS3 protein expression in the ECM surrounding tumor tissues. We explored the unique ability of HAS3 in the ECM to synthesize HA (50~100 KDa) and inhibit tumor growth in vivo using three different models, namely xenograft (MDA-MB-231), allograft (E0771), and PDX (TNBC) mice model. We also demonstrated that HAS3-induced G2/M phase cell growth cycle arrest in cancer cells through activation of α-tubulin acetylation induces mitophagy and autophagic cell death. This study suggests that HAS3 derived HA, a component of the microenvironment in breast tissue encompassed in cutaneous tissue, directly influences human tumor growth. |
