Knockdown of the β1 integrin subunit reduces primary tumor growth and inhibits pancreatic cancer metastasis

Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
International Journal of Cancer (Impact Factor: 5.09). 12/2011; 129(12):2905-15. DOI: 10.1002/ijc.25942
Source: PubMed


To address the role of β(1) integrins in pancreatic cancer progression, we stably knocked down β(1) integrin subunit expression in human FG-RFP pancreatic cancer cells using lentiviral-based RNA interference. We then examined the effects of β(1) integrin subunit knockdown on pancreatic cancer cell adhesion, migration and proliferation on tumor microenvironment-specific extracellular matrix proteins in vitro and on tumor progression in vivo using a clinically relevant fluorescent orthotopic mouse model of pancreatic cancer. Knockdown of the β(1) integrin subunit inhibited cell adhesion, migration and proliferation on types I and IV collagen, fibronectin and laminin in vitro. In vivo, knockdown of the β(1) integrin subunit reduced primary tumor growth by 50% and completely inhibited spontaneously occurring metastasis. These observations indicate a critical role for the β(1) integrin subunit in pancreatic cancer progression and metastasis in particular. Our results suggest the β(1) integrin subunit as a therapeutic target for the treatment of pancreatic cancer, especially in the adjuvant setting to prevent metastasis of this highly aggressive cancer.

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Available from: Hop Sanderson Tran Cao, Oct 02, 2015
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    • "For example, α1β1, α2β1, α10β1 and α11β1 are collagen-binding integrins; α3β1, α6β1 and α7β1 bind to laminin and α4β1, α5β1, α8β1 and αvβ1 bind to fibronectin [30]. In many cancer types, integrin beta 1 promotes cancer cell proliferation and survival and regulates cell focal adhesion and tumor metastasis [31], [32], [33], [34]. Masumoto reported that a monoclonal antibody against ITGB1 blocked HCC cell invasion [35], and Mizuno found that overexpression of α3β1 integrins enhanced HepG2 cell migration and invasion [36], while inhibition of α3β1 integrins suppressed SMMC-7721 cell migration [37]. "
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    ABSTRACT: MicroRNAs (miRNAs) are small, single-stranded, non-coding RNAs that play pivotal roles in human cancer development and progression, such as tumor metastasis. Here, we identified the miRNAs that regulate hepatocellular carcinoma (HCC) cell migration by a high-throughput screening method using the classical wound-healing assay with time-lapse video microscopy and validation with a transwell migration assay. Eleven miRNAs (miR-134, -146b-3p, -188-3p, -525-3p, -661, -767-5p, -891a, -891b, -1244, -1247 and miR-1471) were found to promote or inhibit HCC cell migration. Further investigation revealed that miR-134 suppressed the invasion and metastasis of HCC cells in vitro and in vivo, and integrin beta 1 (ITGB1) was a direct and functional target gene of miR-134. Moreover, miR-134 inhibited the phosphorylation of focal adhesion kinase (FAK) and the activation of RhoA downstream of the ITGB1 pathway, thereby decreasing stress fiber formation and cell adhesion in HCC cells. In conclusion, we demonstrated that miR-134 is a novel metastasis suppressor in HCC and could be a potential therapeutic target for the treatment of HCC.
    PLoS ONE 02/2014; 9(2):e87665. DOI:10.1371/journal.pone.0087665 · 3.23 Impact Factor
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    • "blocked cancer cell migration and invasion in vitro (Arao et al, 2000; Ryschich et al, 2009). In vivo, knockdown of b1 integrin reduced primary tumour growth by 50% and completely inhibited spontaneously occurring metastasis (Grzesiak et al, 2011). Consistently, our data provide additional insights to the combined blockage of integrin a2 and b1 subunits as a potential intervention in PDAC. "
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    ABSTRACT: Background: Pancreatic stellate cells (PSCs) promote metastasis as well as local growth of pancreatic cancer. However, the factors mediating the effect of PSCs on pancreatic cancer cells have not been clearly identified. Methods: We used a modified Boyden chamber assay as an in vitro model to investigate the role of PSCs in migration of Panc1 and UlaPaCa cells and to identify the underlying mechanisms. Results: PSC supernatant (PSC-SN) dose-dependently induced the trans-migration of Panc1 and UlaPaCa cells, mainly via haptokinesis and haptotaxis, respectively. In contrast to poly-L-lysine or fibronectin, collagen I resembled PSC-SN with respect to its effect on cancer cell behaviours, including polarised morphology, facilitated adhesion, accelerated motility and stimulated trans-migration. Blocking antibodies against integrin α2/β1 subunits significantly attenuated PSC-SN- or collagen I-promoted cell trans-migration and adhesion. Moreover, both PSC-SN and collagen I induced the formation of F-actin and focal adhesions in cells, which was consistent with the constantly enhanced phosphorylation of focal adhesion kinase (FAK, Tyr397). Inhibition of FAK function by an inhibitor or small interference RNAs significantly diminished the effect of PSC-SN or collagen I on haptotaxis/haptokinesis of pancreatic cancer cells. Conclusion: Collagen I is the major mediator for PSC-SN-induced haptokinesis of Panc1 and haptotaxis of UlaPaCa by activating FAK signalling via binding to integrin α2β1.
    British Journal of Cancer 11/2013; 110(2). DOI:10.1038/bjc.2013.706 · 4.84 Impact Factor
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    • "Within this context, the β1 integrin subunit is almost universally expressed in tumor cells, where interactions with specific matrix ligands, such as collagen, laminin and fibronectin are dictated, in part, by the identity of the integrin α subunit partner [13]. In some human solid tumors, increased expression of certain β1 integrins, for example α2β1 [14], α3β1 [15], [16], α5β1 [17], [18], or α6β1 [19], correlates with increased metastatic potential [20]–[23], and in some cases with shortened patient survival [17], [24]–[30]. On the other hand, α2β1 may suppress the progression of certain tumors [31], [32]. "
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    ABSTRACT: After neoplastic cells leave the primary tumor and circulate, they may extravasate from the vasculature and colonize tissues to form metastases. β1 integrins play diverse roles in tumorigenesis and tumor progression, including extravasation. In blood cells, activation of β1 integrins can be regulated by "inside-out" signals leading to extravasation from the circulation into tissues. However, a role for inside-out β1 activation in tumor cell metastasis is uncertain. Here we show that β1 integrin activation promotes tumor metastasis and that activated β1 integrin may serve as a biomarker of metastatic human melanoma. To determine whether β1 integrin activation can influence tumor cell metastasis, the β1 integrin subunit in melanoma and breast cancer cell lines was stably knocked down with shRNA and replaced with wild-type or constitutively-active β1. When tumor cells expressing constitutively-active β1 integrins were injected intravenously into chick embryos or mice, they demonstrated increased colonization of the liver when compared to cells expressing wild-type β1 integrins. Rescue expression with mutant β1 integrins revealed that tumor cell extravasation and hepatic colonization required extracellular ligand binding to β1 as well as β1 interaction with talin, an intracellular mediator of integrin activation by the Rap1 GTPase. Furthermore, shRNA-mediated knock down of talin reduced hepatic colonization by tumor cells expressing wild-type β1, but not constitutively-active β1. Overexpression in tumor cells of the tumor suppressor, Rap1GAP, inhibited Rap1 and β1 integrin activation as well as hepatic colonization. Using an antibody that detects activated β1 integrin, we found higher levels of activated β1 integrins in human metastatic melanomas compared to primary melanomas, suggesting that activated β1 integrin may serve as a biomarker of invasive tumor cells. Altogether, these studies establish that inside-out activation of β1 integrins promotes tumor cell extravasation and colonization, suggesting diagnostic and therapeutic approaches for targeting of β1 integrin signaling in neoplasia.
    PLoS ONE 10/2012; 7(10):e46576. DOI:10.1371/journal.pone.0046576 · 3.23 Impact Factor
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