The role of death receptor 3 in the biological behavior of hepatocellular carcinoma cells

Induction of Apoptosis by Metabolites of Rhei Radix et Rhizoma (Da Huang): A Review of the Potential Mechanism in Hepatocellular Carcinoma

Liver cancer is a global disease with a high mortality rate and limited treatment options. Alternations in apoptosis of tumor cells and immune cells have become an important method for detailing the underlying mechanisms of hepatocellular carcinoma (HCC). Bcl-2 family, Caspase family, Fas and other apoptosis-related proteins have also become antagonistic targets of HCC. Da Huang (Rhei Radix et Rhizoma, RR), a traditional Chinese herb, has recently demonstrated antitumor behaviors. Multiple active metabolites of RR, including emodin, rhein, physcion, aloe-emodin, gallic acid, and resveratrol, can successfully induce apoptosis and inhibit HCC. However, the underlying mechanisms of these metabolites inhibiting the occurrence and development of HCC by inducing apoptosis is complicated owing to the multi-target and multi-pathway characteristics of traditional Chinese herbs. Accordingly, this article reviews the pathways of apoptosis, the relationship between HCC and apoptosis, the role and mechanism of apoptosis induced by mitochondrial endoplasmic reticulum pathway and death receptor pathway in HCC and the mechanism of six RR metabolites inhibiting HCC by inducing apoptosis.

Identification and Validation of the lncRNA BACE1-AS as Immune-Related Influencing Factor in Tumorigenesis following Pan-Carcinoma Analysis

BACKGROUND

The lncRNA BACE1-AS was identified as a plasma molecular marker in the early diagnosis of Alzheimer's disease, but its role in tumors remains poorly defined.

METHODS

The expression patterns, genomic mutation, and prognostic significance of BACE1-AS in pan-cancers were compared by analyzing 32 types of tumors from The Cancer Genome Atlas and cBioPortal databases. The relationships between BACE1-AS expression levels and the degree of immune cell infiltration, immune components, and immune-related genes were explored. The possible molecular mechanisms of BACE1-AS in tumors were explored using gene set enrichment analysis (GSEA). Finally, the role of BACE1-AS in hepatocellular carcinoma was confirmed via quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

BACE1-AS expression levels were significantly upregulated in LIHC, GBM, KIRC, CHOL, STAD, KICH, COAD, and PRAD. Higher expression levels of BACE1-AS were associated with worse overall survival in patients with HNSC and LIHC, while the opposite was found in PCPG and THCA. The overall mutation rate of BACE1-AS in pan-cancer was only approximately 0.9%, and it occurred mainly in uveal melanoma and uterine carcinoma. Generally, BACE1-AS expression was negatively correlated with the immune microenvironment. BACE1-AS expression was mainly related to naïve B cells, activated memory CD4 T cells, monocytes, M1 macrophages, M2 macrophages, and resting mast cells. The potential mechanisms of BACE1-AS in tumors were mainly via regulating the activities of B cell-mediated immunity, immune response regulating cell surface receptor signaling, RNA binding in posttranscriptional gene silencing, B cell receptor signaling pathways, and immune receptor activity. Finally, the qRT-PCR results confirmed that the expression levels of BACE1-AS in hepatocellular carcinoma cell lines were upregulated.

CONCLUSIONS

Overall, our results suggest that BACE1-AS is associated with the expression, prognosis, and rate of immune cell infiltration of most tumors. Thus, BACE1-AS may be a potential target for immunotherapies aimed at improving cancer patient outcomes.

Tumor suppression effect of targeting periostin with siRNA in a nude mouse model of human laryngeal squamous cell carcinoma

BACKGROUND

The incidence of laryngeal carcinoma is increasing, however, the mechanism is not fully understood. We aimed to investigate the efficacy of periostin gene silencing by siRNA on tumor inhibition, in a novel nude mouse model of human laryngeal squamous cell carcinoma, and to explore possible inhibitory mechanisms.

METHODS

Tumors were established in nude mice by transplantation of LSCC AMC-HN-8 cell line. Forty-eight nude mice were randomly divided into groups of eight each, and treated with high (1.0 OD) or low (0.5 OD) doses of periostin-siRNA or appropriate control solutions. Tumor growth was observed and used to calculate an inhibition rate (%). Routine pathological and electron microscopic examination were used to determine tumor apoptosis and proliferation. Changes in periostin mRNA and protein levels were analyzed.

RESULTS

Tumor growth was significantly inhibited in mice treated by high dose periostin-siRNA compared to untreated and those treated with low dose periostin-siRNA (P < 0.05). Pathological examination showed increased tumor necrosis and apoptotic changes in treated mice, which was confirmed by electron microscopy. Periostin mRNA and protein expression were significantly reduced in tumors from mice treated with high dose periostin-siRNA, compared to controls and low-dose periostin-siRNA treatment groups (P < 0.05).

CONCLUSION

Periostin silencing was associated with growth inhibition of tumor cells in a nude mouse model of LSCC. The underlying mechanism may be due to receptor-mediated induction of relevant signal transduction pathways that modulate the microenvironment needed for cancer cell survival. Periostin is expected to become a new target for cancer therapy.

Development of small-molecule immune checkpoint inhibitors of PD-1/PD-L1 as a new therapeutic strategy for tumour immunotherapy

Cancer immunotherapy has been increasingly utilised to treat advanced malignancies. The signalling network of immune checkpoints has attracted considerable attention. Immune checkpoint inhibitors are revolutionising the treatment options and expectations for patients with cancer. The reported clinical success of targeting the T-cell immune checkpoint receptors PD-1/PD-L1 has demonstrated the importance of immune modulation. Indeed, antibodies binding to PD-1 or PD-L1 have shown remarkable efficacy. However, antibody drugs have many disadvantages, such as their production cost, stability, and immunogenicity and, therefore, small-molecule inhibitors of PD-1 and its ligand PD-L1 are being introduced. Small-molecule inhibitors could offer inherent advantages in terms of pharmacokinetics and druggability, thereby providing additional methods for cancer treatment and achieving better therapeutic effects. In this review, we first discuss how PD-1/PD-L1-targeting inhibitors modulate the relationship between immune cells and tumour cells in tumour immunotherapy. Second, we discuss how the immunomodulatory potential of these inhibitors can be exploited via rational combinations with immunotherapy and targeted therapy. Third, this review is the first to summarise the current clinical and preclinical evidence regarding small-molecule inhibitors of the PD-1/PD-L1 immune checkpoint, considering features and responses related to the tumours and to the host immune system.