Yeasmin Shamima, Nakayama Kentaro, Rahman Mohammed Tanjimur, Rahman Munmun, Ishikawa Masako, Katagiri Atsuko, Iida Kouji, Nakayama Naomi, Miyazaki Kohji
Department of Obstetrics and Gynecology, Shimane University School of Medicine, Enyacho 89-1, Izumo, Shimane, 6938501, Japan.
Tumour Biol. 2011 Aug;32(4):661-70. doi: 10.1007/s13277-011-0166-5. Epub 2011 Apr 14.
Our previous studies indicate that loss of MKK4 expression is associated with the progression of ovarian cancer. However, direct evidence that MKK4 inhibits the malignant phenotype of ovarian cancer cells is limited. In the current study, we investigated the mechanism relating loss of MKK4 expression to the development of ovarian cancer. Using cell growth and anchorage-independent assays, we determined that both the growth and colony-forming ability of MKK4-transfected TOV-21G cells, a line with a homozygous deletion of MKK4, were significantly reduced compared to control vector-transfected cells. Overexpression of the MKK4 gene in TOV-21G cells resulted in reduced proliferative activity and increased apoptosis. To confirm that MKK4 expression related to tumor suppress function, we used two independent but complementary approaches. MKK4 gene knockdown in OVK18#2 and MDAH2774 cells, which overexpressed MKK4, increased proliferation activity. Additionally, the engineered expression of MKK4 in SKOV3 cells, a line with low endogenous MKK4 expression, produced a phenotype similar to that of TOV-21G. Similar results were produced in tumor xenografts in nude mice. These results indicated that MKK4 acts as a tumor suppressor and may represent an important therapeutic target for the treatment of ovarian cancer.
我们之前的研究表明，MKK4表达缺失与卵巢癌进展相关。然而，MKK4抑制卵巢癌细胞恶性表型的直接证据有限。在本研究中，我们探究了MKK4表达缺失与卵巢癌发生发展相关的机制。通过细胞生长和非锚定依赖性分析，我们确定，与对照载体转染细胞相比，MKK4转染的TOV-21G细胞（该细胞系存在MKK4纯合缺失）的生长和集落形成能力均显著降低。TOV-21G细胞中MKK4基因的过表达导致增殖活性降低和凋亡增加。为证实MKK4表达与肿瘤抑制功能相关，我们采用了两种独立但互补的方法。在过表达MKK4的OVK18#2和MDAH2774细胞中敲低MKK4基因可增加增殖活性。此外，在低内源性MKK4表达的SKOV3细胞中通过基因工程表达MKK4，产生了与TOV-21G细胞相似的表型。在裸鼠肿瘤异种移植实验中也得到了类似结果。这些结果表明，MKK4作为一种肿瘤抑制因子，可能是治疗卵巢癌的重要治疗靶点。
