Nutrition is believed to be a primary contributor in regulating gene expression by affecting epigenetic pathways such as DNA methylation and histone modification. Resveratrol and pterostilbene are phytoalexins produced by plants as part of their defense system. These two bioactive compounds when used alone have been shown to alter genetic and epigenetic profiles of tumor cells, but the concentrations employed in various studies often far exceed physiologically achievable doses. Triple-negative breast cancer (TNBC) is an often fatal condition that may be prevented or treated through novel dietary-based approaches.HCC1806 and MDA-MB-157 breast cancer cells were used as TNBC cell lines in this study. MCF10A cells were used as control breast epithelial cells to determine the safety of this dietary regimen. CompuSyn software was used to determine the combination index (CI) for drug combinations.Combinatorial resveratrol and pterostilbene administered at close to physiologically relevant doses resulted in synergistic (CI <1) growth inhibition of TNBCs. SIRT1, a type III histone deacetylase (HDAC), was down-regulated in response to this combinatorial treatment. We further explored the effects of this novel combinatorial approach on DNA damage response by monitoring γ-H2AX and telomerase expression. With combination of these two compounds there was a significant decrease in these two proteins which might further resulted in significant growth inhibition, apoptosis and cell cycle arrest in HCC1806 and MDA-MB-157 breast cancer cells, while there was no significant effect on cellular viability, colony forming potential, morphology or apoptosis in control MCF10A breast epithelial cells. SIRT1 knockdown reproduced the effects of combinatorial resveratrol and pterostilbene-induced SIRT1 down-regulation through inhibition of both telomerase activity and γ-H2AX expression in HCC1806 breast cancer cells. As a part of the repair mechanisms and role of SIRT1 in recruiting DNMTs, the effects of this combination treatment was also explored on DNA methyltransferases (DNMTs) expression. Interestingly, the compounds resulted in a significant down-regulation of DNMT enzymes with no significant effects on DNMT enzyme expression in MCF10A control cells.Collectively, these results provide new insights into the epigenetic mechanisms of a novel combinatorial nutrient control strategy that exhibits synergy and may contribute to future recalcitrant TNBC prevention and/or therapy.
Purpose: The aim of the study was to determine the restoration of hip biomechanics through lateral offset, leg length, and acetabular component position when comparing non-arthroplasty surgeons (NAS) to elective arthroplasty surgeons (EAS). Methods: 131 patients, with a femoral neck fracture treated with a THA by 7 EAS and 20 NAS, were retrospectively reviewed. 2 blinded observers measured leg-length discrepancy, femoral offset, and acetabular component position. Multivariate logistic regression models examined the association between the surgeon groups and restoration of lateral femoral, acetabular offset, leg length discrepancy, acetabular anteversion, acetabular position, and component size, while adjusting for surgical approach and spinal pathology. Results: NAS under-restored 4.8 mm of lateral femoral offset (43.9 ± 8.7 mm) after THA when compared to the uninjured side (48.7 ± 7.1 mm, p = 0.044). NAS were at risk for under-restoring lateral femoral offset when compared to EAS ( p = 0.040). There was no association between lateral acetabular offset, leg length, acetabular position, or component size and surgeon type. Conclusions: Lateral femoral offset is at risk for under-restoration after THA for femoral neck fractures, when performed by surgeons that do not regularly perform elective THA. This indicates that lateral femoral offset is an under-appreciated contributor to hip instability when performing THA for a femoral neck fracture. Lateral femoral offset deserves as much attention and awareness as acetabular component position since a secondary analysis of our data reveal that preoperative templating and intraoperative imaging did not prevent under-restoration.
Purpose: Distraction osteogenesis (DO) promotes endogenous bone formation across a mechanically controlled environment, providing anatomical and functional replacement of deficient tissue. The application of DO, to the appendicular skeleton, has revolutionized the treatment of many congenital and acquired defects. Here, we describe the development of a novel mouse distraction model for the tibia. Methods: Tibial distraction devices were manufactured using computer-aided design (CAD) software (SolidWorks) and 3D-printing (AW3D AXIOM 3D Printer). One 0.6 mm hole was drilled 3mm anterior and one 3mm posterior to a line dividing the tibial crest. An osteotomy was performed at the tibial crest using a diamond disc saw (Brasseler, Inc.). Distraction plates were secured with insertion of tight fit 0.65 mm screws (McMaster-Carr). Animals were divided into four groups: sham (exposure of the tibia and device placement without osteotomy), fracture (osteotomy without distraction), acutely lengthened, and gradually distracted. The gradual distraction protocol consisted of a 5-day latency period after the initial osteotomy and fixation of the distraction device, followed by 10 days of distraction at a rate of 0.15 mm every 12 hours, and 28 days of bone consolidation and remodeling. For our acute lengthening protocol, a 3.0 mm lengthening was performed following a 5-day latency period, with a consolidation period ending at 43 days post-operation. Results: Bone successfully regenerated within the surgically created gap using the novel distraction device. Micro computed tomography (CT) images of the sham group presented native, unperturbed bone, while the acute lengthening group images showed the absence of bone regeneration at the site of the osteotomy. Bone regeneration occurred in the fracture group and the gradual distraction group. Upon quantitative analysis, the bone volume per tissue volume (BV/TV) (***P<0.001) and callus volume (CV) (****P<0.0001) were significantly higher in the distraction group compared to the sham group. Finally, histological staining through Movat Pentachrome determine the tissue types present within the gap of the four groups. Pentachrome staining of the acute group stained for fibrous tissue at the site of the osteotomy. Pentachrome staining of the fracture group indicated an overt presence of cartilage, and the staining in the distraction group showed the formation of new bone. Conclusions: We have developed a new model for long bone distraction osteogenesis in the mouse. Future work will include applying this model to investigate the mechanisms underlying bone regeneration, and potential therapeutics that can quicken regeneration.
