2013年6月21日訊 /生物谷BIOON/--發表在Nature雜誌上的文章稱,羅切斯特大學科學家發現了保護裸鼴鼠從不患癌症的化學物質。該發現為治療癌症提供了新的思路。
裸鼴鼠是一種小型,無毛,生活在地下的一種嚙齒類動物,該鼠壽命為30年,並且在其一生中從未換癌症。由Seluanov博士和Gorbunova博士帶領的研究團隊發現保護該裸鼴鼠免患癌症的原因,由於其組織中富含高分子量的透明質酸(high molecular weight hyaluronan ,HMW-HA)。
研究人員注意到培養裸鼴鼠細胞的培養基中經常有粘性物質聚集。而在培養人類細胞,小鼠細胞,以及豚鼠細胞的培養基中卻沒有該物質。於是研究人員開始關注於這個種粘性物質。
Seluanov博士稱,我們要知道這些粘性物質是什麼。於是研究人員發現了該物質是HMW-HA,接著研究人員想檢查是否是HMW-HA賦予了裸鼴鼠抗癌的能力。
研究人員發現,當HMW-HA被移除時,該細胞對癌症敏感,表明HMW-HA在裸鼴鼠癌症抗性方面有重要作用。研究人員同時發現了一個稱之為HAS2的基因,該基因負責在裸鼴鼠中製造HMW-HA。奇怪的是,裸鼴鼠的HAS2基因不同於其他物種的HAS2基因。而且裸鼴鼠的HMW-HA降解過程非常緩慢,這就造成了該物質在機體中大量聚集。
於是研究人員檢測了HMW-HA在小鼠中的效果。如果效果明顯,Seluanov博士和Gorbunova博士細胞在人類細胞中檢驗其效果。Seluanov博士稱,有些間接證據表明HMW-HA在人類中有效果,如在注射除皺和緩解膝關節疼痛等方面,而且沒有副作用。我們希望HMW-HA在抗癌過程中同樣有效果。
Gorbunova博士稱,大量的癌症研究集中在易於患有癌症的動物上,我們則反其道而行之,希望在天生抗癌的動物中找到靈感。
Seluanov博士和Gorbunova博士之前的研究顯示在裸鼴鼠中P16基因能夠在細胞數量過大時阻斷細胞增殖過程。而在最近的研究中,他們發現HMW-HA能夠激活p16的抗癌活性。
Seluanov博士和Gorbunova博士接下來打算研究HMW-HA在人類癌症治療和預防方面是否有臨床意義。(生物谷Bioon.com)
High-molecular-mass hyaluronan mediates the cancer resistance of the naked mole rat
Xiao Tian, Jorge Azpurua, Christopher Hine, Amita Vaidya, Max Myakishev-Rempel, Julia Ablaeva, Zhiyong Mao, Eviatar Nevo, Vera Gorbunova, Andrei Seluanov
The naked mole rat (Heterocephalus glaber) displays exceptional longevity, with a maximum lifespan exceeding 30?years1, 2, 3. This is the longest reported lifespan for a rodent species and is especially striking considering the small body mass of the naked mole rat. In comparison, a similarly sized house mouse has a maximum lifespan of 4?years4, 5. In addition to their longevity, naked mole rats show an unusual resistance to cancer. Multi-year observations of large naked mole-rat colonies did not detect a single incidence of cancer2, 6. Here we identify a mechanism responsible for the naked mole rat’s cancer resistance. We found that naked mole-rat fibroblasts secrete extremely high-molecular-mass hyaluronan (HA), which is over five times larger than human or mouse HA. This high-molecular-mass HA accumulates abundantly in naked mole-rat tissues owing to the decreased activity of HA-degrading enzymes and a unique sequence of hyaluronan synthase 2 (HAS2). Furthermore, the naked mole-rat cells are more sensitive to HA signalling, as they have a higher affinity to HA compared with mouse or human cells. Perturbation of the signalling pathways sufficient for malignant transformation of mouse fibroblasts fails to transform naked mole-rat cells. However, once high-molecular-mass HA is removed by either knocking down HAS2 or overexpressing the HA-degrading enzyme, HYAL2, naked mole-rat cells become susceptible to malignant transformation and readily form tumours in mice. We speculate that naked mole rats have evolved a higher concentration of HA in the skin to provide skin elasticity needed for life in underground tunnels. This trait may have then been co-opted to provide cancer resistance and longevity to this species.