The anti-hepatocellular carcinoma activity of Mel-P15 is mediated by natural killer cells

Anticancer activities of natural antimicrobial peptides from animals

Cancer is the most common cause of human death worldwide, posing a serious threat to human health and having a negative impact on the economy. In the past few decades, significant progress has been made in anticancer therapies, but traditional anticancer therapies, including radiation therapy, surgery, chemotherapy, molecular targeted therapy, immunotherapy and antibody-drug conjugates (ADCs), have serious side effects, low specificity, and the emergence of drug resistance. Therefore, there is an urgent need to develop new treatment methods to improve efficacy and reduce side effects. Antimicrobial peptides (AMPs) exist in the innate immune system of various organisms. As the most promising alternatives to traditional drugs for treating cancers, some AMPs also have been proven to possess anticancer activities, which are defined as anticancer peptides (ACPs). These peptides have the advantages of being able to specifically target cancer cells and have less toxicity to normal tissues. More and more studies have found that marine and terrestrial animals contain a large amount of ACPs. In this article, we introduced the animal derived AMPs with anti-cancer activity, and summarized the types of tumor cells inhibited by ACPs, the mechanisms by which they exert anti-tumor effects and clinical applications of ACPs.

The Dynamic Role of NK Cells in Liver Cancers: Role in HCC and HBV Associated HCC and Its Therapeutic Implications

Hepatocellular carcinoma (HCC) remains an important complication of chronic liver disease, especially when cirrhosis occurs. Existing treatment strategies include surgery, loco-regional techniques, and chemotherapy. Natural killer cells are distinctive cytotoxic lymphocytes that play a vital role in fighting tumors and infections. As an important constituent of the innate immune system against cancer, phenotypic and functional deviations of NK cells have been demonstrated in HCC patients who also exhibit perturbation of the NK-activating receptor/ligand axis. The rate of recurrence of tumor-infiltrating and circulating NK cells are positively associated with survival benefits in HCC and have prognostic significance, suggesting that NK cell dysfunction is closely related to HCC progression. NK cells are the first-line effector cells of viral hepatitis and play a significant role by directly clearing virus-infected cells or by activating antigen-specific T cells by producing IFN-γ. In addition, chimeric antigen receptor (CAR) engineered NK cells suggest an exclusive opportunity to produce CAR-NKs with several specificities with fewer side effects. In the present review, we comprehensively discuss the innate immune landscape of the liver, particularly NK cells, and the impact of tumor immune microenvironment (TIME) on the function of NK cells and the biological function of HCC. Furthermore, the role of NK cells in HCC and HBV-induced HCC has also been comprehensively elaborated. We also elaborate on available NK cell-based immunotherapeutic approaches in HCC treatment and summarize current advancements in the treatment of HCC. This review will facilitate researchers to understand the importance of the innate immune landscape of NK cells and lead to devising innovative immunotherapeutic strategies for the systematic treatment of HCC.

Delivery Strategies for Melittin-Based Cancer Therapy

Melittin (MLT) has been studied preclinically as an anticancer agent based on its broad lytic effects in multiple tumor types. However, unsatisfactory tissue distribution, hemolysis, rapid metabolism, and limited specificity are critical obstacles that limit the translation of MLT. Emerging drug delivery strategies hold promise for targeting, controlled drug release, reduced side effects, and ultimately improved treatment efficiency. In this review, we discuss recent advances in the use of diverse carriers to deliver MLT, with an emphasis on the design and mechanisms of action. We further outline the opportunities for MLT-based cancer immunotherapy.

The Roles of circRNAs in Liver Cancer Immunity

Circular RNAs (circRNAs) are stable covalently closed non-coding RNAs (ncRNAs). Many studies indicate that circRNAs are involved in the pathological and physiological processes of liver cancer. However, the functions of circRNAs in liver cancer immunity are less known. In this review, we summarized the functions of circRNAs in liver cancer, including proliferative, metastasis and apoptosis, liver cancer stemness, cell cycle, immune evasion, glycolysis, angiogenesis, drug resistance/sensitizer, and senescence. Immune escape is considered to be one of the hallmarks of cancer development, and circRNA participates in the immune escape of liver cancer cells by regulating natural killer (NK) cell function. CircRNAs may provide new ideas for immunotherapy in liver cancer.

The role of natural killer cells in hepatocellular carcinoma development and treatment: A narrative review

A major obstacle for treatment of HCC is the inadequate efficacy and limitation of the available therapeutic options. Despite the recent advances in developing novel treatment options, HCC still remains one of the major causes of cancer morbidity and mortality around the world. Achieving effective treatment and eradication of HCC is a challenging task, however recent studies have shown that targeting Natural Killer cells, as major regulators of immune system, can help with the complete treatment of HCC, restoration of normal liver function and subsequently higher survival rate of HCC patients. Studies have shown that decrease in the frequency of NK cells, their dysfunction due to several factors such as dysregulation of receptors and their ligands, and imbalance of different types of inhibitory and stimulating microRNA expression is associated with higher rate of HCC progression and development, and poor survival outcome. Here in our review, we mainly focused on the importance of NK cells in HCC development and treatment.

circRNA of AR-suppressed PABPC1 91 bp enhances the cytotoxicity of natural killer cells against hepatocellular carcinoma via upregulating UL16 binding protein 1

Hepatocellular carcinoma (HCC) is a heterogeneous malignancy type with limited approaches for treatment. Additionally, inappropriate immune therapy indicates that the understanding the underlying mechanism of HCC is necessary. The aim of the present study was to investigate the influence of a novel circular RNA (circRNA), circRNA of AR-suppressed PABPC1 91 bp (CircARSP91), on immune surveillance induced by natural killer (NK) cells. An in vitro cell cytotoxicity assay was performed to determine the cytotoxicity of NK cells against HCC cells. A specific plasmid for circRNA overexpression was used to establish stable cell lines. Additionally, samples from patients with HCC were analyzed to determine the association between the present in vitro data and those of clinical settings. CircARSP91 could increase the susceptibility of HCC cells to NK cell cytotoxicity. Following screening multiple factors that could influence the activation of NK cells, it was determined that such a phenotype may be caused by upregulating UL16 binding protein 1 (ULBP1) expression in HCC cells at the mRNA and protein levels. Additionally, the data generated from patient samples significantly support a positive association between CircARSP91 and ULBP1. In conclusion, CircARSP91 could enhance innate immune surveillance by strengthening the cytotoxicity of NK cells, implying that circRNA may serve a role in tumor immunity.

DNA methylation biomarkers for hepatocellular carcinoma

Background

Aberrant methylation of DNA is a key driver of hepatocellular carcinoma (HCC). In this study, we sought to integrate four cohorts profile datasets to identify such abnormally methylated genes and pathways associated with HCC.

Methods

To this end, we downloaded microarray datasets examining gene expression (GSE84402, GSE46408) and gene methylation (GSE73003, GSE57956) from the GEO database. Abnormally methylated differentially expressed genes (DEGs) were sorted and pathways were analyzed. The String database was then used to perform enrichment and functional analysis of identified pathways and genes. Cytoscape software was used to create a protein-protein interaction network, and MCODE was used for module analysis. Finally, overall survival analysis of hub genes was performed by the OncoLnc online tool.

Results

In total, we identified 19 hypomethylated highly expressed genes and 14 hypermethylated lowly expressed genes at the screening step, and finally found six mostly changed hub genes including MAD2L1, CDC20, CCNB1, CCND1, AR and ESR1. Pathway analysis showed that aberrantly methylated-DEGs mainly associated with the cell cycle process, p53 signaling, and MAPK signaling in HCC. After validation in TCGA database, the methylation and expression status of hub genes was significantly altered and same with our results. Patients with high expression of MAD2L1, CDC20 and CCNB1 and low expression of CCND1, AR, and ESR1 was associated with shorter overall survival.

Conclusions

Taken together, we have identified novel aberrantly methylated genes and pathways linked to HCC, potentially offering novel insights into the molecular mechanisms governing HCC progression and serving as novel biomarkers for precision diagnosis and disease treatment.

Acid-Activated Melittin for Targeted and Safe Antitumor Therapy

Melittin (MLT), as a natural active biomolecule, can penetrate the tumor cell membrane to play a role in cancer treatment and will attract more attention in future development of antitumor drugs. The main component of natural bee venom MLT was modified by introducing a pH-sensitive amide bond between the 2,3-dimethyl maleimide (DMMA) and the lysine (Lys) of MLT (MLT-DMMA). MLT and its corresponding modified peptide MLT-DMMA were used for antitumor and biocompatibility validation. The biomaterial characteristics were tested by MALDI-TOF MS, ¹H NMR, IUPAC and HPLC, cell viability, hemolytic and animal experiment safety evaluation. Compared with the primary melittin, the modified peptide showed decreased surface charge and low cytotoxicity in physiological conditions. Moreover, cell assays confirmed the acid-activated conversion of amide bond resulting in adequate safety during delivery and timely antitumor activity in tumor lesions. Thus, MLT-DMMA provided a feasible platform to improve the targeted and safe antitumor applications.