Doxycycline-inducible expression of SPARC/osteonectin/BM40 in MDA-MB-231 human breast cancer cells results in growth inhibition
Doxycycline-inducible expression of SPARC/osteonectin/BM40 in MDA-MB-231 human breast cancer cells results in growth inhibition
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DOI：
10.1023/a:1016536725958
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发表时间：
2002-09-01
影响因子：
3.8
通讯作者：
Thompson, EW
中科院分区：
文献类型：
--
作者：
Dhanesuan, N;Sharp, JA;Thompson, EW
BM 40/Osteonectin是一种对细胞行为有多种影响的基质细胞蛋白。在体外，它的主要已知功能是抗粘附和抗增殖，并且它与体内组织重塑和癌症有关。在包括乳腺癌在内的许多癌症中过表达，并且这种效应似乎是细胞类型特异性的。为了研究cDNA 3对乳腺癌的影响，我们使用Tet-On诱导系统将cDNA 3转染到MDA-MB-231 BAG（人乳腺癌细胞系）中。通过Western分析，我们发现MDA-MB-231 BAG和克隆X亲本细胞中的背景水平较低，并且多西环素处理后，在MDA-MB-231 BAG转染的克隆X5、X21、X24和X75中显著诱导了MDA-MB-231 BAG蛋白表达。诱导的表达不影响细胞形态或粘附胶原I型和IV型，但它减缓了贴壁培养的增殖速度。细胞周期分析显示，顺铂延缓了细胞向S期的进程。在培养的伤口愈合试验中，强力霉素诱导的伤口愈合也减慢了单层伤口闭合的速率。胸苷抑制增殖消除了这种效果，证实这是由于抗增殖，而不是抑制迁移。与此一致，我们无法检测到多西环素刺激的细胞的迁移和基质胶生长分析的任何差异。我们的结论是，ESTA是抑制人类乳腺癌细胞增殖，并不刺激迁移，相反，它的刺激作用报告的黑色素瘤（增殖和迁移）和胶质瘤（迁移）细胞。据报道，卵巢癌细胞也有类似的生长抑制，这可能是癌细胞的共同特征。
SPARC (secreted protein acidic and rich in cysteine)/BM40/Osteonectin is a matricellular protein with multiple effects on cell behaviour. In vitro, its major known functions are anti-adhesive and anti-proliferative, and it is associated with tissue remodelling and cancer in vivo. SPARC is overexpressed in many cancers, including breast cancer, and the effects of SPARC seem to be cell type-specific. To study the effects of SPARC on breast cancer, we transfected SPARC into the MDA-MB-231 BAG, human breast cancer cell line using the Tet-On inducible system. By western analysis, we found low background levels in the MDA-MB-231 BAG and clone X parental cells, and prominent induction of SPARC protein expression after doxycycline treatment in SPARC transfected clones X5, X21, X24 and X75. Induction of SPARC expression did not affect cell morphology or adhesiveness to collagens type I and IV, but it slowed the rate of proliferation in adherent cultures. Cell cycle analysis showed that SPARC slowed the progression to S phase. Doxycycline induction of SPARC also slowed the rate of monolayer wound closure in the cultured wound healing assay. Thymidine inhibition of proliferation abrogated this effect, confirming that it was due to anti-proliferation rather than inhibition of migration. Consistent with this, we were unable to detect any differences in migration and Matrigel outgrowth analysis of doxycycline-stimulated cells. We conclude that SPARC is inhibitory to human breast cancer cell proliferation, and does not stimulate migration, in contrast to its stimulatory effects reported for melanoma (proliferation and migration) and glioma (migration) cells. Similar growth repression by SPARC has been reported for ovarian cancer cells, and this may be a common feature among carcinomas.