In this study, poly(lactic acid) (PLA) scaffolds were prepared by selective enzymatic degradation using poly(3-hydrobutyrate-co-4-hydrobutyrate) [P(3HB-co-4HB)] depolymerase. The porous morphology and properties of the scaffolds were investigated to clarify whether the microstructure of the biomimetic extracellular matrix is suitable for cell proliferation and differentiation. When the P(3HB-co-4HB) composition of PLA/P(3HB-co-4HB) blends was changed from 50 wt% to 60 wt%, the mean pore diameter of the porous PLA scaffolds increased from 64.15 µm to 80.01 µm, the porosity significantly improved from 68.45% to 79.88%, and the compressive modulus decreased from 9.34 MPa to 6.94 MPa. PLA40 with 60% P(3HB-co-4HB) blending was used in in vitro degradation and mouse embryo fibroblast (MEF) cell culture tests. The results demonstrated that the PLA scaffolds were degraded completely into harmless products in simulated body fluid (SBF) solution at a slow degradation rate, and the weight loss of the scaffolds could reach 80% after 8 months of in vitro degradation. Meanwhile, the PLA scaffolds showed the largest swelling value of 157.4% after immersion in SBF solution for 14 days. Cell viability was determined through scanning electron microscopy (SEM) and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) tests. The results showed that the PLA scaffolds supported the attachment and growth of MEF cells. Compared with the PLA scaffolds without any modification, the PLA scaffolds modified by poly-L-lysine exhibited a better biocompatibility to MEF cells. These results indicate that selective enzymatic degradation has a potential application in scaffold manufacturing.

Juglanthraquinone C (JC), a naturally occurring anthraquinone extracted from Juglans mandshurica, could induce apoptosis of cancer cells. This study aims to investigate the detailed cytotoxicity mechanism of JC in HepG2 and BEL‐7402 cells. The Affymetrix HG‐U133 Plus 2.0 arrays were first used to analyze the mRNA expression exposed to JC or DMSO in HepG2 cells. Consistent with the previous results, the data indicated that JC could induce apoptosis and hyperactivated Akt. The Western blot analysis further revealed that Akt, a well‐known survival protein, was strongly activated in HepG2 and BEL‐7402 cells. Furthermore, an obvious inhibitory effect on JC‐induced apoptosis was observed when the Akt levels were decreased, while the overexpression of constitutively active mutant Akt greatly accelerated JC‐induced apoptosis. The subsequent results suggested that JC treatment suppressed nuclear localization and increased phosphorylated levels of Foxo3a, and the overexpression of Foxo3a abrogated JC‐induced apoptosis. Most importantly, the inactivation of Foxo3a induced by JC further led to an increase of intracellular ROS levels by suppressing ROS scavenging enzymes, and the antioxidant N‐acetyl‐L‐cysteine and catalase successfully decreased JC‐induced apoptosis. Collectively, this study demonstrated that JC induced the apoptosis of hepatocellular carcinoma (HCC) cells by activating Akt/Foxo signaling pathway and increasing intracellular ROS levels.

Hematopoietic stem cells (HSCs) exhibit significant functional and metabolic alterations within the lung cancer microenvironment, contributing to tumor progression and immune evasion by increasing differentiation into myeloid-derived suppressor cells (MDSCs). Our aim is to analyze the metabolic transition of HSCs from glycolysis to oxidative phosphorylation (OXPHOS) in lung cancer and determine its effects on HSC functionality. Using a murine Lewis Lung Carcinoma lung cancer model, we conducted metabolic profiling of long-term and short-term HSCs, as well as multipotent progenitors, comparing their metabolic states in normal and cancer conditions. We measured glucose uptake using 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino]-2-Deoxyglucose (2-NBDG) and assessed levels of lactate, acetyl-coenzyme A, and ATP. Mitochondrial functionality was evaluated through flow cytometry, alongside the impact of the glucose metabolism inhibitor 2-DG on HSC differentiation and mitochondrial activity. HSCs under lung cancer conditions showed increased glucose uptake and lactate production, with an associated rise in OXPHOS activity, marking a metabolic shift. Treatment with 2-DG led to decreased T-HSCs and MDSCs and an increased red blood cell count, highlighting its potential to influence metabolic and differentiation pathways in HSCs. This study provides novel insights into the metabolic reprogramming of HSCs in lung cancer, emphasizing the critical shift from glycolysis to OXPHOS and its implications for the therapeutic targeting of cancer-related metabolic pathways.

Hepatocellular carcinoma (HCC) is a highly heterogeneous and immunosuppressive malignancy that frequently exhibits poor responses to immunotherapy, primarily due to immune evasion mediated by myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Despite increasing interest in MDSC-targeted strategies, effective approaches to selectively modulate MDSC function and enhance immunotherapeutic efficacy remain limited. Recent advances in nanotechnology have led to the development of nanodrug delivery systems, particularly for small interfering RNA (siRNA), offering advantages such as protection from degradation and improved delivery specificity. However, traditional liposomal carriers often suffer from low selectivity and widespread biodistribution, increasing the risk of off-target effects. In this study, we designed a pH-responsive lipid nanoparticle (Lip@si-YTHDF2) for the targeted delivery of siRNA against YTHDF2. This approach aimed to suppress MDSC function, inhibit CSC-mediated immune escape, and enhance immunotherapy in HCC. Bioinformatic analyses of GEO and TCGA-LIHC datasets revealed elevated YTHDF2 expression in HCC and its association with poor prognosis. Functional studies in a conditional YTHDF2-knockout mouse model demonstrated that YTHDF2 regulates MDSC activity and promotes tumor progression by stabilizing MYC mRNA through N6-methyladenosine (m6A) modification. Our findings demonstrated that Lip@si-YTHDF2 effectively downregulated MYC expression, diminished the immunosuppressive phenotype of MDSCs, restored T cell-mediated anti-tumor immunity, and significantly inhibited tumor growth in combination with PD-1 checkpoint blockade. This study not only elucidates a novel YTHDF2/m6A/MYC axis in immune evasion but also provides a clinically relevant siRNA delivery platform with promising therapeutic implications for improving HCC immunotherapy.

Mitochondrial fission is a tightly regulated process involving multiple proteins and cell signaling. Despite extensive studies on mitochondrial fission factors, our understanding of the regulatory mechanisms remains limited. This study shows the critical role of a mitochondrial GTPase, GTPBP8, in orchestrating mitochondrial fission in mammalian cells. Depletion of GTPBP8 resulted in drastic elongation and interconnectedness of mitochondria. Conversely, overexpression of GTPBP8 shifted mitochondrial morphology from tubular to fragmented. Notably, the induced mitochondrial fragmentation from GTPBP8 overexpression was inhibited in cells either depleted of the mitochondrial fission protein Drp1 (also known as DNM1L) or carrying mutated forms of Drp1. Importantly, downregulation of GTPBP8 caused an increase in oxidative stress, modulating cell signaling involved in the increased phosphorylation of Drp1 at Ser637. This phosphorylation hindered the recruitment of Drp1 to mitochondria, leading to mitochondrial fission defects. By contrast, GTPBP8 overexpression triggered enhanced recruitment and assembly of Drp1 at mitochondria. In summary, our study illuminates the cellular function of GTPBP8 as a pivotal modulator of the mitochondrial division apparatus, inherently reliant on its influence on Drp1.