These beneficial effects make rhNRG-1 promising as a broad-spectrum therapeutic for the treatment of heart failure due to a variety of common cardiac diseases.

Blockade of the mitogen-activated protein (MAP) kinase pathway suppresses growth of colon cancer in vivo. Here we demonstrate a direct link between the extracellular signal-regulated kinase ERK2 and the growth-promoting cell adhesion molecule, integrin avb6, in colon cancer cells. Down-regulation of b6 integrin subunit expression inhibits tumour growth in vivo and MAP kinase activity in response to serum stimulation. In avb6-expressing cells ERK2 is bound only to the b6 subunit. The increase in cytosolic MAP kinase activity upon epidermal growth factor stimulation is all accounted for by b6-bound ERK. Deletion of the ERK2 binding site on the b6 cytoplasmic domain inhibits tumour growth and leads to an association between ERK and the b5 subunit. The physical interaction between integrin avb6 and ERK2 de®nes a novel paradigm of integrin-mediated signalling and provides a therapeutic target for cancer treatment.

Background: Stem cell–conditioned medium (CM) has been increasingly used in regenerative medicine. However, its effect on graft-host integration after anterior cruciate ligament (ACL) reconstruction (ACLR) remains unclear. Purpose: To examine the effect of human bone marrow stem cell (hBMSC)–CM on graft-bone integration and graft midsubstance ligamentization in a rat model of ACLR. Study Design: Controlled laboratory study. Methods: CM was obtained from the supernatant of commercially available hBMSCs in serum-free Dulbecco’s modified Eagle medium (DMEM). In a rat model of an ACL injury, isometric ACLR was performed. Three groups were established: CM injection group (CM; n = 40), control injection group (CI; n = 40) with serum-free DMEM injections, and no injection group (NI; n = 40). An intra-articular injection was performed weekly. Micro–computed tomography was conducted at 2, 4, and 8 weeks postoperatively. Histological and biomechanical analyses were conducted at 4 and 8 weeks postoperatively. The NIH3T3 fibroblast was utilized as a model in vitro to examine the effect of CM using the cell counting kit–8 (CCK-8) assay and immunofluorescence staining of Ki-67, α–smooth muscle actin (α-SMA), and collagen 1 (Col 1). Results: At 4 and 8 weeks, the femoral and tibial bone tunnel areas as well as the interface between the graft and host bone were smaller, while the bone volume/total volume ratio was higher, in the CM group. Sharpey-like fibers formed at 8 weeks in the CM group. At 4 and 8 weeks, more Col 1 was noticed in the CM group than in the NI group (both P < .001) or CI group (both P < .001). Immunohistochemically, the α-SMA–positive area was up-regulated at the graft-bone interface at 4 weeks ( P < .001) and declined at 8 weeks ( P < .001) in the CM group compared with the other 2 groups. At the midsubstance, α-SMA expression decreased from 4 to 8 weeks in all groups and was significantly lower in the CM group than in the NI group ( P < .01) or CI group ( P < .05) at 8 weeks. The CCK-8 assay showed that CM increased NIH3T3 viability ( P < .001) and the level of Ki-67 ( P < .05), α-SMA ( P < .001), and Col 1 ( P < .001) in CM-educated NIH3T3 cells. Conclusion: hBMSC-CM accelerates graft-bone incorporation and midsubstance ligamentization and enhances the proliferation, differentiation, and collagen synthesis of fibroblasts. Clinical Relevance: Graft-host integration is essential after ACLR. The current study identified a novel agent, that is, hBMSC-CM, as a candidate for promoting integration.

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