Regulation of NF-kB Signalling Through the PR55β-RelA Interaction in Osteoblasts

NOS2 and COX-2 Co-Expression Promotes Cancer Progression: A Potential Target for Developing Agents to Prevent or Treat Highly Aggressive Breast Cancer

Nitric oxide (NO) and reactive nitrogen species (RNS) exert profound biological impacts dictated by their chemistry. Understanding their spatial distribution is essential for deciphering their roles in diverse biological processes. This review establishes a framework for the chemical biology of NO and RNS, exploring their dynamic reactions within the context of cancer. Concentration-dependent signaling reveals distinctive processes in cancer, with three levels of NO influencing oncogenic properties. In this context, NO plays a crucial role in cancer cell proliferation, metastasis, chemotherapy resistance, and immune suppression. Increased NOS2 expression correlates with poor survival across different tumors, including breast cancer. Additionally, NOS2 can crosstalk with the proinflammatory enzyme cyclooxygenase-2 (COX-2) to promote cancer progression. NOS2 and COX-2 co-expression establishes a positive feed-forward loop, driving immunosuppression and metastasis in estrogen receptor-negative (ER-) breast cancer. Spatial evaluation of NOS2 and COX-2 reveals orthogonal expression, suggesting the unique roles of these niches in the tumor microenvironment (TME). NOS2 and COX2 niche formation requires IFN-γ and cytokine-releasing cells. These niches contribute to poor clinical outcomes, emphasizing their role in cancer progression. Strategies to target these markers include direct inhibition, involving pan-inhibitors and selective inhibitors, as well as indirect approaches targeting their induction or downstream effectors. Compounds from cruciferous vegetables are potential candidates for NOS2 and COX-2 inhibition offering therapeutic applications. Thus, understanding the chemical biology of NO and RNS, their spatial distribution, and their implications in cancer progression provides valuable insights for developing targeted therapies and preventive strategies.

TNF-α-induced Inhibition of Protein Myristoylation Via Binding Between NMT1 and Sorbs2 in Osteoblasts

BACKGROUND/AIM

Bone resolution due to tumor invasion often occurs on the surface of the jaw and is important for clinical prognosis. Although cytokines, such as TNF-α are known to impair osteoblasts, the underlying mechanism remains unclear. Protein myristoylation, a post-translational modification, plays an important role in the development of immune responses and cancerization of cells. A clear understanding of the mechanisms underlying this involvement will provide insights into molecular-targeted therapies. N-myristoyltransferase1 (NMT1), a specific enzyme involved in myristoylation, is expressed in cancer cells and in other normal cells, suggesting that changes in myristoylation may result from the regulation of NMT1 in cancer cells.

MATERIALS AND METHODS

Using newly emerging state-of-the-art techniques such as the Click-it assay, RNA interference, mass spectrometry, immunoprecipitation, immunocytochemistry, and western blotting, the expression of myristoylated proteins and the role of TNF-α stimulation on NMT1 and Sorbs2 binding were evaluated in a murine osteoblastic cell line (MC3T3-E1).

RESULTS

The expression of myristoylated proteins was detected; however, TNF-α stimulation resulted in their inhibition in MC3T3-E1 cells. The expression of NMT1 also increased. Immunoprecipitation and mass spectrometry identified Sorbs2 as a novel binding protein of NMT1, which upon TNF-α stimulation, inhibited myristoylation.

CONCLUSION

The binding between NMT1 and Sorbs2 can regulate myristoylation, and NMT1 can be considered as a potential target molecule for tumor invasion.

Resveratrol-loaded titania nanotube coatings promote osteogenesis and inhibit inflammation through reducing the reactive oxygen species production via regulation of NF-κB signaling pathway

Although titanium and its alloys are widely used in bone surgeries, the implantation failures caused by sterile inflammation still occur. The excessive reactive oxygen species (ROS) in the peri-implant region are considered to cause inflammation and impede the osseointegration of titanium implants. In this study, a coating of resveratrol-loaded titania nanotube (TNT-Res) for eliminating ROS was fabricated on titanium surface through electrochemical anodization and following surface adsorption of resveratrol. The resveratrol concentration of released from TNT-Res coating was controlled by modulating the loading amount. The ROS production in macrophage cell lineage RAW 264.7 and bone mesenchymal stem cells (BMSCs) were significantly decreased when cultured on TNT-Res coatings. The pro-inflammatory factors, including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β), and NO produced by RAW 264.7 cells were reduced when cells were cultured on TNT-Res coatings. These results proved that the TNT-Res coating can effectively eliminate ROS and inhibit inflammation. Moreover, the osteogenic indicators, including alkaline phosphatase (ALP) production, extracellular calcium deposition, and osteogenesis-related gene expression, including collagen І (Col-І), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (Runx2), were significantly promoted for TNT-Res groups, which demonstrated that the TNT-Res coating can enhance the osteogenic differentiation of BMSCs. Additionally, the phosphorylation of nuclear factor κ-B (NF-κB) were down-regulated both in RAW 264.7 cells and BMSCs, which indicated that the TNT-Res coating could inhibit inflammation and promote osteogenesis by inhibiting the activation of NF-κB signaling pathway. The TNT-Res coating could be an effective implant surface for improving osseointegration ability of titanium implants.

Chios Mastic Gum Consumption Has a Protective Effect on Ovariectomy-Induced Bone Loss in Rats

The purpose of this study was to examine the potential effect of Chios Mastic Gum (CMG) consumption on bone mineral density (BMD) and strength of ovariectomized rats. CMG is a known resin used from ancient times for its beneficial biological properties. Thirty mature female Wistar rats were randomized into three equal groups: sham-operated (control), ovariectomized (OVX), and ovariectomized and administered CMG per os (OVX+CMG). BMD of the total tibia, proximal tibia, and the 6th lumbar vertebra were measured at baseline and at 3 and 6 months post ovariectomy. Bone strength was assessed with three-point-bending (3pb) of the right femur. At 3 and 6 months, BMD values of the OVX+CMG group were significantly higher for the anatomical cites evaluated than those of the OVX group. Femoral thickness assessed via 3pb had intermediate values in the treated group compared to the other groups. Cytology of vaginal smears and uterine weight of the OVX+CMG group were consistent with estrogen depletion. Gastrocnemius muscle and intraperitoneal fat ratios to body weight (BW) of the OVX+CMG group did not significantly differ from the control group. Daily consumption CMG had a protective effect on BMD of the total and proximal tibia and the 6th lumbar vertebra of the rats, without causing undesirable effects on the vaginal epithelium and uterus. The 3pb results also demonstrated a favorable effect on the thickness of rat femurs. In addition, CMG was beneficial for both the muscular system and the intraperitoneal fat/BW ratio of the rats.