Motility Induction in Breast Carcinoma by Mammary Epithelial Laminin 332 (Laminin 5)

Abstract

Host interactions with tumor cells contribute to tumor progression by several means. This study was done to determine whether mammary epithelium could interact with breast carcinoma by producing substances capable of inducing motility in the cancer cells. Conditioned medium of immortalized 184A1 mammary epithelium collected in serum-free conditions induced dose-dependent motility in the MCF-7 breast carcinoma cell line by both a semiquantitative scattering assay and a Boyden chamber assay. Purification of the motility factor revealed that it was laminin 332 (formerly laminin 5) by mass spectroscopy. A Western blot of the 184A1 conditioned medium using a polyclonal antibody confirmed the presence of laminin 332 in the conditioned medium. Blockage of the motility with antibodies to the laminin 332 and its receptor components, alpha(3) and beta(1) integrins, provided further evidence that tumor cell motility was caused by the laminin 332 in the conditioned medium. Invasion of MCF-7, BT-20, and MDA-MB-435 S was induced by purified laminin 332 and 184A1 conditioned medium and blocked by an anti-alpha(3) integrin antibody. Staining of carcinoma in situ from breast cancer specimens revealed that laminin 332 in the myoepithelium adjacent to the preinvasive cells provided a source of laminin 332 that could potentially encourage the earliest steps of stromal invasion. In metaplastic breast carcinomas, the presence of laminin 332-producing cells coexpressing alpha(3) integrin and the greater metastatic potential of tumors with higher laminin 332 levels suggest that laminin 332 expression is associated with aggressive features in these human breast cancers.

LAMC2 enhances the metastatic potential of lung adenocarcinoma

“…LAM-332 was reported to be a scatter or motility factor secreted by tumor cells or normal epithelial cells, inducing motility of gastric cancer, 30 melanoma, 31 and breast cancer cells. 32 To determine whether LAMC2 was secreted by the lung ADC cells, cells were cultivated in RPMI-1640 without additives, serum, or other growth factors for 24 h. The conditioned medium was then collected, followed by ultracentrifugal filter concentration (Supplementary Figure S3A). Immunoblot analysis using the concentrated conditioned medium identified secreted unprocessed (140 kDa) and processed (100 kDa) LAMC2 (Figure 3a), whereas the 100 kDa LAMC2 was detected in the cell lysates at much lower level than in conditioned medium (data not shown).…”

Laminin-332-Rich Tumor Microenvironment for Tumor Invasion in the Interface Zone of Breast Cancer

“…[23][24][25] Therefore, increased expression of laminin-332 in the IZ may be the product of the proximate paracrine intercellular interaction between invasive tumor cells in the TZ and the myofibroblasts (InF) in the IZ to prepare a suitable microenvironment for tumor invasion. Laminin-332-rich tumor microenvironment in the IZ may be able to continuously stimulate integrin-related signaling pathways for migration and survival of the invading tumor cells.…”

“…Taken together, we propose that InF may be responsible for tumor invasion based on laminin-332 and MT1-MMP overexpression. Laminin-332 is now widely recognized to induce the motility of cancer cells with integrins, 25 and is associated with breast cancer metastasis. 32 In addition, MT1-MMP derived from fibroblasts promotes tumor progression.…”

Integrin α3β1 controls mRNA splicing that determines cyclooxygenase-2 (Cox-2) mRNA stability in breast cancer cells

“…Preclinical studies have shown that a3b1 promotes malignant behavior of breast cancer cells in vivo and in vitro (Cagnet et al, 2013;Mitchell et al, 2010;Morini et al, 2000;Scales et al, 2013;Sugiura and Berditchevski, 1999;Wang et al, 2004), as well as skin tumorigenesis in vivo (Sachs et al, 2012), implicating this integrin as a potential therapeutic target to inhibit cancer progression and metastasis (Subbaram and DiPersio, 2011). Laminin-332, a major ECM ligand for a3b1, is often expressed highly in breast cancer cells, where it enhances motility (Carpenter et al, 2009;Carpenter et al, 2008). At least some functions of a3b1 in transformed or immortalized cells are attributable to the ability of a3b1 to regulate genes that stimulate invasive growth and/or angiogenesis, including matrix metalloproteinase-9 (MMP-9) (Iyer et al, 2005;Morini et al, 2000) and cyclooxygenase (Cox-2, also known as prostaglandin G/H synthase 2 in human) (Mitchell et al, 2010).…”