As immune checkpoint inhibitors (ICIs) continue to advance, more evidence has emerged that anti-PD-1/PD-L1 immunotherapy is an effective treatment against cancers. Known as the programmed death ligand-1 (PD-L1), this co-inhibitory ligand contributes to T cell exhaustion by interacting with programmed death-1 (PD-1) receptor. However, cancer-intrinsic signaling pathways of the PD-L1 molecule are not well elucidated. Therefore, the present study aimed to evaluate the regulatory network of PD-L1 and lay the basis of successful use of anti-PD-L1 immunotherapy in acute myeloid leukemia (AML). Data for AML patients were extracted from TCGA and GTEx databases. The downstream signaling pathways of PD-L1 were identified via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The key PD-L1 related genes were selected by weighted gene co-expression network analysis (WGCNA), MCC algorithm and Molecular Complex Detection (MCODE). The CCK-8 assay was used to assess cell proliferation. Flow cytometry was used to determine cell apoptosis and cell cycle. Western blotting was used to identify the expression of the PI3K-AKT signaling pathway. PD-L1 was shown to be elevated in AML patients when compared with the control group, and high PD-L1 expression was associated with poor overall survival rate. The ECM-receptor interaction, as well as the PI3K-AKT signaling pathway, were important PD-L1 downstream pathways. All three analyses found eight genes (ITGA2B, ITGB3, COL6A5, COL6A6, PF4, NMU, AGTR1, F2RL3) to be significantly associated with PD-L1. Knockdown of PD-L1 inhibited AML cell proliferation, induced cell apoptosis and G2/M cell cycle arrest. Importantly, PD-L1 knockdown reduced the expression of PI3K and p-AKT, but PD-L1 overexpression increased their expression. The current study elucidates the main regulatory network and downstream targets of PD-L1 in AML, assisting in the understanding of the underlying mechanism of anti-PD-1/PD-L1 immunotherapy and paving the way for clinical application of ICIs in AML.

Cancer is a serious threat to human health, and chemotherapy for cancer is limited by severe side effects. Curcumin (CUR) is a commonly used natural product for antitumor treatment without safety concerns. However, low bioavailability and poor tumor accumulation are great obstacles for its clinical application. Our previous research has demonstrated that platelet membrane-camouflaged nanoparticles can efficiently ameliorate the in vivo kinetic characteristics and enhance the tumor affinity of payloads. Nevertheless, the antitumor efficiency of this formulation still needs to be thoroughly investigated, and its drug release behavior is limited. Herein, CUR-loaded platelet membrane bioinspired chitosan-modified liposome (PCLP-CUR) was constructed to improve CUR release. PCLP-CUR was shown to have long retention time, improved bioavailability, strong tumor targeting capacity and effective cellular uptake. The incorporation of chitosan enabled PCLP-CUR to release cargoes quickly under mild acidic tumor conditions, leading to more complete drug release and favoring subsequent treatment. Both in vitro and in vivo investigations showed that PCLP-CUR could significantly enhance the anticancer efficacy of CUR with minimal side effects through biomimetic membrane and chitosan modification. In summary, this developed delivery system can provide a promising strategy for tumor-targeting therapy and phytochemical delivery.

Acute myeloblastic leukemia (AML) is a disease with a high rate of relapse and drug resistance due to the remaining leukemic stem cells (LSCs). Therefore, LSCs are specific targets for the treatment of leukemia. CD123 is specifically expressed on LSCs and performs as a specific marker. Curcumin is the main active compound of a natural product with low toxicity for humans. It has been reported to inhibit leukemic cell growth. However, curcumin is practically insoluble in water and has low bioavailability. In this study, we aimed to formulate curcumin nanoparticles and conjugate with the anti-CD123 to overcome the low water solubility and improve the targeting of LSCs. The cytotoxicity of both curcumin-loaded PLGA/poloxamer nanoparticles (Cur-NPs) and anti-CD123-curcumin-loaded PLGA/poloxamer nanoparticles (anti-CD123-Cur-NPs) were examined in KG-1a cells. The results showed that Cur-NPs and Cur-NPs-CD123 exhibited cytotoxic effects on KG-1a cells with the IC₅₀ values of 74.20 ± 6.71 and 41.45 ± 5.49 µM, respectively. Moreover, anti-CD123-Cur-NPs induced higher apoptosis than Cur-NPs. The higher uptake of anti-CD123-Cur-NPs in KG-1a cells was confirmed by using flow cytometry. In conclusion, the anti-CD123-Cur-NPs formulation improved curcumin’s bioavailability and specific targeting of LSCs, suggesting that it is a promising drug delivery system for improving the therapeutic efficacy against AML.

Cancer is a major threat to the health of humans. Recently, various natural products including curcumin (CCM) have attracted enormous interest for efficacious cancer therapy. However, natural therapeutic agents still encounter certain challenges such as rapid clearance, low bioavailability, and poor tumor targeting. Recently, the platelet membrane (PM) camouflaged nanoparticle has provided a promising solution for cancer targeting therapy. Nevertheless, only limited efforts have been dedicated to systematically explore the mechanism of affinity between PM bioinspired nanoparticles and various tumor cells. Herein, a CCM-encapsulated platelet membrane biomimetic lipid vesicle (CCM@PL) with a size of 163.2 nm, zeta potential of −31.8 mV and encapsulation efficiency of 93.62% was developed. The values of the area under the concentration-time curve and mean residence time for CCM@PL were 3.08 times and 3.04 times those of CCM, respectively. Furthermore, this PM biomimetic carrier showed an excellent affinity against Huh-7, SK-OV-3 and MDA-MB-231 cell lines due to the biomolecular interaction between P-selectin on the PM and tumoral CD44 receptors. In addition, CCM@PL displayed enhanced cytotoxicity compared with free CCM and the synthetic formulation. Overall, our results suggest that this developed PM biomimetic lipid nanovector has great potential for targeted cancer treatment and natural components delivery.

Estimating the post mortem interval (PMI) is a crucial and contentious issue in forensic research, particularly in criminal cases. Traditional methods for PMI estimation are limited by constraints and inaccuracies. Circular RNA (circRNA), formed through exon or intron looping to create a complete circular structure without a 5′ end cap and a 3′ poly(A) tail, exhibits exceptional stability, abundance, and tissue-specific characteristics that make it potentially valuable for PMI estimation. However, research on the exploration or application of circRNA in PMI estimation has been limited. This study aims to investigate the correlation between circRNA and PMI. In this study, liver tissue samples were collected from mice at six different time points at 4 °C, 18 °C, 25 °C, and 35 °C, respectively. The reference gene 28S rRNA and the biomarker circRnf169 were successfully screened. Quantitative PCR was employed to examine the correlation between circRnf169 levels and PMI. At 4 °C, the level of circRnf169 decreased with prolonged PMI, whereas at 18 °C, 25 °C, and 35 °C, the circRnf169 RNA was degraded rapidly, indicating that circRnf169 is suitable for PMI estimation at low temperatures or early PMI. These findings suggest the establishment of mathematical model for early PMI based on circRnf169 using liver tissue, which may serve as a reliable marker. Further research is required in order to develop more markers in mice and/or to validate these mathematical models in human samples.

Leukemic cells remaining in the body is the main problem for cancer patients, and these cells are called Leukemic Stem Cells (LSCs). Many studies have revealed that the overexpression of the Wilms’ tumor 1 (WT1) protein is related to leukemogenesis. Curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) from Thai turmeric (Curcuma longa Linn.) are the focus of this study because they have been previously been reported to show potent antileukemic activity. This study aims to investigate the cytotoxic effect of in-house curcuminoids on the human leukemic stem cell line (KG-1a) when compared to other leukemic cell lines (KG-1 and K562). MTT assays were used to determine the cytotoxicity of curcuminoids at various concentrations. Curcumin exhibited the strongest cytotoxic activity on KG-1a cells with IC₅₀ values of 13.6 ± 1.9 µM. To determine the effect of curcuminoids on WT1 and CD34 protein expressions by Western blotting, KG-1a cells were treated with noncytotoxic concentrations (IC₂₀ value). Bisdemethoxycurcumin showed the strongest suppression of WT1 and CD34 protein expressions with 73.3 ± 1.4 and 82.9 ± 2.0%, respectively. In summary, curcuminoids, especially bisdemethoxycurcumin, could inhibit WT1 and CD34 protein expressions. Thus, bisdemethoxycurcumin is a compound that calls for further studies of its process in the inhibition of WT1 and CD34 expressions in LSCs for the leukemia treatment.