Gemcitabine Inhibits the Progression of Pancreatic Cancer by Restraining the WTAP/MYC Chain in an m6A-Dependent Manner

PURPOSE

Pancreatic cancer (PC) is a common malignant tumor of the digestive system, and its 5-year survival rate is only 4%. N6-methyladenosine (m6A) RNA methylation is the most common post-transcriptional modification and dynamically regulates cancer development, while its role in PC treatment remains unclear.

MATERIALS AND METHODS

We treated PC cells with gemcitabine and quantified the overall m6A level with m6A methylation quantification. Real-time quantitative reverse transcription polymerase chain reaction and Western blot analyses were used to detect expression changes of m6A regulators. We verified the m6A modification on the target genes through m6A-immunoprecipitation (IP), and further in vivo experiments and immunofluorescence (IF) assays were applied to verify regulation of gemcitabine on Wilms' tumor 1-associated protein (WTAP) and MYC.

RESULTS

Gemcitabine inhibited the proliferation and migration of PC cells and reduced the overall level of m6A modification. Additionally, the expression of the "writer" WTAP was significantly downregulated after gemcitabine treatment. We knocked down WTAP in cells and found target gene MYC expression was significantly downregulated, m6A-IP also confirmed the m6A modification on MYC. Our experiments showed that m6A-MYC may be recognized by the "reader" IGF2BP1. In vivo experiments revealed gemcitabine inhibited the tumorigenic ability of PC cells. IF analysis also showed that gemcitabine inhibited the expression of WTAP and MYC, which displayed a significant trend of co-expression.

CONCLUSION

Our study confirmed that gemcitabine interferes with WTAP protein expression in PC, reduces m6A modification on MYC and RNA stability, thereby inhibiting the downstream pathway of MYC, and inhibits the progression of PC.

High-Strength Smart Microneedles with "Offensive and Defensive" Effects for Intervertebral Disc Repair

Intervertebral disc degeneration (IVDD) is a global public health issue. The injury of annulus fibrosus (AF) caused by acupuncture or discectomy can trigger IVDD again. However, there is currently no suitable method for treating AF injury. In this study, the high-strength smart microneedles (MNs) which can penetrate the AF tissue through a local and minimally invasive method, and achieve remote control of speeded-up release of the drug and hyperthermia by the Near Infrared is developed. The PDA/GelMA composite MNs loaded with diclofenac sodium are designed to extracellularly "offend" the inflammatory microenvironment and mitigate damage to cells, and intracellularly increase the level of cytoprotective heat shock proteins to enhance the defense against the hostile microenvironment, achieving "offensive and defensive" effects. In vitro experiments demonstrate that the synergistic treatment of photothermal therapy and anti-inflammation effectively reduces inflammation, inhibits cell apoptosis, and promotes the synthesis of the extracellular matrix (ECM). In vivo experiments show that the MNs mitigate the inflammatory response, promote ECM deposition, reduce the level of apoptosis, and restore the biomechanical properties of the intervertebral disc (IVD) in rats. Overall, this high-strength smart MNs display promising "offensive and defensive" effects that can provide a new strategy for IVD repair.

Moderate mechanical stimulation antagonizes inflammation of annulus fibrosus cells through YAP-mediated suppression of NF-κB signaling

Intervertebral disc degeneration (IDD) is a leading cause of low back pain. The inflammatory responses caused by aberrant mechanical loading are one of the major factors leading to annulus fibrosus (AF) degeneration and IDD. Previous studies have suggested that moderate cyclic tensile strain (CTS) can regulate anti-inflammatory activities of AF cells (AFCs), and Yes-associated protein (YAP) as a mechanosensitive coactivator senses diverse types of biomechanical stimuli and translates them into biochemical signals controlling cell behaviors. However, it remains poorly understood whether and how YAP mediates the effect of mechanical stimuli on AFCs. In this study, we aimed to investigate the exact effects of different CTS on AFCs as well as the role of YAP signaling involving in it. Our results found that 5% CTS inhibited the inflammatory response and promoted cell growth through inhibiting the phosphorylation of YAP and nuclear localization of NF-κB, while 12% CTS had a significant proinflammatory effect with the inactivation of YAP activity and the activation of NF-κB signaling in AFCs. Furthermore, moderate mechanical stimulation may alleviate the inflammatory reaction of intervertebral discs through YAP-mediated suppression of NF-κB signaling in vivo. Therefore, moderate mechanical stimulation may serve as a promising therapeutic approach for the prevention and treatment of IDD.