STAT6 knockdown using multiple siRNA sequences inhibits proliferation and induces apoptosis of human colorectal and breast cancer cell lines.

The transcription factor STAT6 is strongly expressed in various tumours and is most highly expressed in human malignant lymphomas and pancreatic, colorectal, prostate and breast cancers. STAT6 is associated with cancer cell proliferation, an increased malignancy and poor prognosis. Thus, techniques aimed at reducing or blocking STAT6 expression may be useful in treating STAT6high cancers. Among these cancers, colorectal and breast cancers represent two of the most common worldwide and their incidence is increasing every year. In 2018, colorectal and breast cancers represented 10.2% and 11.6% of all new cases of cancer diagnosed, respectively. In this study, four proprietary STAT6 specific small interfering RNA (siRNA) sequences were tested in vitro using the human colon adenocarcinoma cell line, HT-29, and the breast/duct carcinoma cell line, ZR-75-1. Decreases in STAT6 mRNA and protein levels were analysed to confirm the transfection was successful and STAT6 knockdown effects were measured by analysing cell proliferation and apoptosis. Results showed that 100nM siRNA concentration was the most effective and, although all individual sequences were capable of significantly inhibiting cell proliferation, STAT6 siRNA sequences 1 and 4 had the largest effects. STAT6 silencing also significantly induced apoptotic events. In conclusion, these results demonstrate that STAT6 siRNA sequences are capable of inhibiting proliferation of and inducing apoptosis of HT-29 colorectal cancer cells and ZR-75-1 breast cancer cells, halving the number of cancer cells in a short period of time. These experiments will be repeated in other STAT6high cancers in vitro, and animal studies in immunocompromised mice have been planned using xenografts of STAT6-expressing human colorectal and breast cancer cells. The STAT6 siRNA sequences therefore represent a potential treatment for STAT6high colorectal and breast cancers and a wide variety of other STAT6-expressing cancers.

Implantation of a Novel Allogeneic Mesenchymal Precursor Cell Type in Patients with Ischemic Cardiomyopathy Undergoing Coronary Artery Bypass Grafting: an Open Label Phase IIa Trial.

Heart failure is a life-limiting condition affecting over 40 million patients worldwide. Ischemic cardiomyopathy (ICM) is the most common cause. This study investigates in situ cardiac regeneration utilizing precision delivery of a novel mesenchymal precursor cell type (iMP) during coronary artery bypass surgery (CABG) in patients with ischemic cardiomyopathy (LVEF < 40 %). The phase IIa safety study was designed to enroll 11 patients. Preoperative scintigraphy imaging (SPECT) was used to identify hibernating myocardium not suitable for conventional myocardial revascularization for iMP implantation. iMP cells were implanted intramyocardially in predefined viable peri-infarct areas that showed poor perfusion, which could not be grafted due to poor target vessel quality. Postoperatively, SPECT was then used to identify changes in scar area. Intramyocardial implantation of iMP cells with CABG was safe with preliminary evidence of efficacy of improved myocardial contractility and perfusion of nonrevascularized territories resulting in a significant reduction in left ventricular scar area at 12 months after treatment. Clinical improvement was associated with a significant improvement in quality of life at 6 months posttreatment in all patients. The results suggest the potential for in situ myocardial regeneration in ischemic heart failure by delivery of iMP cells.

Shear stress-induced shedding of soluble intercellular adhesion molecule-1 from saphenous vein endothelium.

Within 6 h, shear stress upregulated intercellular adhesion molecule-1 (ICAM-1) (two- to four-fold, P<0.001) and induced matrix metalloproteinase-2 (MMP-2) in cultured human saphenous vein endothelial cells. By 8 h endothelial ICAM-1 levels returned to baseline, with concomitant increase in soluble ICAM-1 (sICAM-1) (P<0.001) and MMP-9 had been induced. Inclusion of a hydroxamate metalloproteinase inhibitor partially reversed the effects on ICAM-1 and sICAM-1 at 8 h, whereas TIMP-1, -2 or -3 had no effect. MMP-9, but not MMP-2, co-immunoprecipitated with ICAM-1. sICAM-1 was processed distal to Arg441, indicating that MMP-9, docking to ICAM-1, contributes to sICAM-1 shedding and attenuation of the shear stress-induced upregulation of ICAM-1.

Flow-dependent increase of ICAM-1 on saphenous vein endothelium is sensitive to apamin.

The potassium channel blocker tetraethylammonium blocks the flow-induced increase in endothelial ICAM-1. We have investigated the subtype of potassium channel that modulates flow-induced increased expression of ICAM-1 on saphenous vein endothelium. Cultured human saphenous vein endothelial cells (HSVECs) or intact saphenous veins were perfused at fixed low and high flows in a laminar shear chamber or flow rig, respectively, in the presence or absence of potassium channel blockers. Expression of K(+) channels and endothelial ICAM-1 was measured by real-time polymerase chain reaction and/or immunoassays. In HSVECs, the application of 0.8 N/m(2) (8 dyn/cm(2)) shear stress resulted in a two- to fourfold increase in cellular ICAM-1 within 6 h (P < 0.001). In intact vein a similar shear stress, with pulsatile arterial pressure, resulted in a twofold increase in endothelial ICAM-1/CD31 staining area within 1.5 h (P < 0.001). Both increases in ICAM-1 were blocked by inclusion of 100 nM apamin in the vein perfusate, whereas other K(+) channel blockers were less effective. Two subtypes of small conductance Ca(2+)-activated K(+) channel (selectively blocked by apamin) were expressed in HSVECs and vein endothelium (SK3>SK2). Apamin blocked the upregulation of ICAM-1 on saphenous vein endothelium in response to increased flow to implicate small conductance Ca(2+)-activated K(+) channels in shear stress/flow-mediated signaling pathways.