MTIF2 impairs 5 fluorouracil-mediated immunogenic cell death in hepatocellular carcinoma in vivo: Molecular mechanisms and therapeutic significance

Research progress in inducing immunogenic cell death of tumor cells

Immunogenic cell death (ICD) is a regulated cell death (RCD) pathway. In response to physical and chemical signals, tumor cells activate specific signaling pathways that stimulate stress responses in the endoplasmic reticulum (ER) and expose damage-associated molecular patterns (DAMPs), which promote antitumor immune responses. As a result, the tumor microenvironment is altered, and many tumor cells are killed. The ICD response in tumor cells requires inducers. These inducers can be from different sources and contribute to the development of the ICD either indirectly or directly. The combination of ICD inducers with other tumor treatments further enhances the immune response in tumor cells, and more tumor cells are killed; however, it also produces side effects of varying severity. New induction methods based on nanotechnology improve the antitumor ability and significantly reduces side effects because they can target tumor cells precisely. In this review, we introduce the characteristics and mechanisms of ICD responses in tumor cells and the DAMPs associated with ICD responses, summarize the current methods of inducing ICD response in tumor cells in five distinct categories: chemical sources, physical sources, pathogenic sources, combination therapies, and innovative therapies. At the same time, we introduce the limitations of current ICD inducers and make a summary of the use of ICD responses in clinical trials. Finally, we provide an outlook on the future of ICD inducer development and provide some constructive suggestions.

Oncolytic Activity of a Chimeric Influenza A Virus Carrying a Human CTLA4 Antibody in Hepatocellular Carcinoma

Oncolytic virotherapy belongs to a kind of active immunotherapy, which could trigger a potent antitumor immune response, showing great potential in clinical application. OVs could induce immune responses through the dual mechanisms of selective tumor killing without destroying normal tissues and induction of systemic antitumor immunity. In this study, we successfully rescued a chimeric oncolytic influenza virus carrying a human CTLA4 antibody in the background of the A/PR/8/34 (PR8) virus. The chimeric virus, called rFlu-huCTLA4, contained the heavy and light chains of the human CTLA4 antibody in the PB1 and PA segments of the PR8 virus, respectively. The first-generation hemagglutination (HA) titers of the rFlu-huCTLA4 virus ranged from 2⁷ to 2⁸, which could be passaged stably in specific pathogen-free (SPF) chicken embryos from P1 to P5. The morphology and size distribution of the chimeric virus were consistent with those of the wt influenza virus. The rFlu-huCTLA4 virus could effectively replicate in various cells in time- and dose-dependent manners. ELISA assay revealed that the secreted huCTLA4 antibody levels in chicken embryos increased gradually over time. Furthermore, MTS and crystal violet analysis showed that the selective cytotoxicity of the virus was higher in hepatocellular carcinoma cells (HepG2 and Huh7) than in normal liver cells (MIHA). In vivo experiments displayed that intratumoral injection with rFlu-huCTLA4 reduced tumor growth and increased the survival of mice compared with the PR8 group. More importantly, in the rFlu-huCTLA4 group, we found that CD4+ and CD8 +T cells were significantly increased in tumor-bearing BALB/c mice. Taken together, these findings demonstrated that the chimeric oncolytic virus rFlu-huCTLA4 could selectively destroy hepatocellular carcinoma cells in vitro and in vivo and may provide a promising clinical strategy for targeted immunotherapy of HCC with the oncolytic flu virus.

LNCAROD enhances hepatocellular carcinoma malignancy by activating glycolysis through induction of pyruvate kinase isoform PKM2

BACKGROUND

Mounting evidence has suggested the essential role of long non-coding RNAs (lncRNAs) in a plethora of malignant tumors, including hepatocellular carcinoma. However, the underlyling mechanisms of lncRNAs remain unidentified in HCC. The present work was aimed to explore the regulatory functions and mechanisms of LncRNA LNCAROD in HCC progression and chemotherapeutic response.

METHODS

The expression of LNCAROD in HCC tissues and cell lines were detected by quantitative reverse transcription PCR (qPCR). Cancer cell proliferation, migration, invasion, and chemoresistance were evaluated by cell counting kit 8 (CCK8), colony formation, transwell, and chemosensitivity assays. Methylated RNA immunoprecipitation qRCR (MeRIP-qPCR) was used to determine N6-methyladenosine (m6A) modification level. RNA immunoprecipitation (RIP) and RNA pull down were applied to identify the molecular sponge role of LNCAROD for modulation of miR-145-5p via the competing endogenous RNA (ceRNA) mechanism, as well as the interaction between LNCAROD and serine-and arginine-rich splicing factor 3 (SRSF3). The interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and LNCAROD was also identified by RIP assay. Gain- or-loss-of-function assays were used to identify the function and underlying mechanisms of LNCAROD in HCC.

RESULTS

We found that LNCAROD was significantly upregulated and predicted a poorer prognosis in HCC patients. LNCAROD upregulation was maintained by increased m6A methylation-mediated RNA stability. LNCAROD significantly promoted HCC cell proliferation, migration, invasion, and chemoresistance both in vitro and in vivo. Furthermore, mechanistic studies revealed that pyruvate kinase isoform M2 (PKM2)-mediated glycolysis enhancement is critical for the role of LNACROD in HCC. According to bioinformatics prediction and our experimental data, LNCAROD directly binds to SRSF3 to induce PKM switching towards PKM2 and maintains PKM2 levels in HCC by acting as a ceRNA against miR-145-5p. The oncogenic effects of LNCAROD in HCC were more prominent under hypoxia than normoxia due to the upregulation of hypoxia-triggered hypoxia-inducible factor 1α.

CONCLUSIONS

In summary, our present study suggests that LNCAROD induces PKM2 upregulation via simultaneously enhancing SRSF3-mediated PKM switching to PKM2 and sponging miR-145-5p to increase PKM2 level, eventually increasing cancer cell aerobic glycolysis to participate in tumor malignancy and chemoresistance, especially under hypoxic microenvironment. This study provides a promising diagnostic marker and therapeutic target for HCC patients.

Identification and validation of potential novel biomarkers to predict distant metastasis in differentiated thyroid cancer

Background

Distant metastasis (DM) is not common in differentiated thyroid cancer (DTC). However, it is associated with a significantly poor prognosis. Early detection of high-risk DTC patients is difficult, and the molecular mechanism is still unclear. Therefore, the present study aims to establish a novel predictive model based on clinicopathological parameters and DM-related gene signatures to provide guidelines for clinicians in decision making.

Methods

Weighted gene co-expression network analysis (WGCNA) was performed to discover co-expressed gene modules and hub genes associated with DM. Univariate and multivariate analyses were carried out to identify independent clinicopathological risk factors based on The Cancer Genome Atlas (TCGA) database. An integrated nomogram prediction model was established. Finally, real hub genes were validated using the GSE60542 database and various thyroid cell lines.

Results

The midnightblue module was most significantly positively correlated with DM (R=0.56, P=9e-06) by as per WGCNA. DLX5 (AUC: 0.769), COX6B2 (AUC: 0.764), and LYPD1 (AUC: 0.760) were determined to be the real hub genes that play a crucial role in predicting DM. Meanwhile, univariate and multivariate analyses demonstrated that T-stage (OR, 15.03; 95% CI, 1.75-319.40; and P=0.024), histologic subtype (OR, 0.17; 95% CI, 0.03-0.92; and P=0.042) were the independent predictors of DM. Subsequently, a nomogram model was constructed based on gene signatures and independent clinical risk factors exhibited good performance. Additionally, the mRNA expressions of real hub genes in the GSE60542 dataset were consistent with TCGA.

Conclusions

The present study has provided a reliable model to predict DM in patients with DTC. This model is likely to serve as an individual risk assessment tool in therapeutic decision-making.