DPP3 Expression Promotes Cell Proliferation and Migration in Vitro and Tumor Growth in Vivo That Associates with Poor Prognosis of Esophageal Carcinoma

Background: Dipeptidyl peptidase III (DPP3) is a zinc-dependent metallopeptidase and elevated in a variety of malignant tumors, but the underlying mechanism is not well understood so far. Here we investigated the association of esophageal carcinogenesis with the regulation of DPP3 expression by tissue-based quantitative analysis and the depletion of DPP3 expression in esophageal cancer cells and xenograft model. Methods: The expression level of DPP3 in esophageal cancer tissues and adjacent normal tissues was detected in 93 cases of tissue biopsies collected from patients diagnosed with esophageal carcinoma by immunohistochemistry. The effect of DPP3 expression on cell proliferation, migration or apoptosis was determined in DPP3-depleted esophageal cancer cells created by infection with the lentivirus containing the shRNA specific to human DPP3 mRNA sequence followed by cytometric detection using celigo cell count assay, flow cytometry, wound-healing assay and trans-well assay as well as chip screening with a Human Apoptosis Antibody Array kit, which enables the quantitative detection of 43 apoptosis-related genes. A xenograft model was applied to the detection of tumor growth and invasion of DPP3-depleted cancer cells in nude mice.Results: DPP3 expression was elevated in esophageal cancer tissues compared with adjacent non-tumor tissues (normal controls) with statistical significance (P<0.05), and associated with poor prognosis of esophageal carcinoma. The DPP3-depletion resulted in a reduced cell proliferation and migration and enhanced cell-cycle arrest and apoptosis of esophageal cancer cells, and lead to the inhibition of tumor growth and invasion in xenograft model. In addition, DPP3-depletion was associated with the upregulation of pro-apoptotic proteins and the downregulation of anti-apoptotic proteins.Conclusions: These findings suggest that DPP3 may promote cell proliferation, migration and survival of esophageal cancer cells in vitro, and tumor growth and invasion of esophageal carcinoma in vivo and this might serve as a molecular target for tumor therapy.

Paliperidone Inhibits Glioblastoma Growth in Mouse Brain Tumor Model and Reduces PD-L1 Expression

A previous study from our group reported that monocyte adhesion to glioblastoma (GBM) promoted tumor growth and invasion activity and increased tumor-associated macrophages (TAMs) proliferation and inflammatory mediator secretion as well. The present study showed that prescribed psychotropic medicine paliperidone reduced GBM growth and immune checkpoint protein programmed death ligand (PD-L)1 expression and increased survival in an intracranial xenograft mouse model. An analysis of the database of patients with glioma showed that the levels of PD-L1 and dopamine receptor D (DRD)2 were higher in the GBM group than in the low grade astrocytoma and non-tumor groups. In addition, GFP expressing GBM (GBM-GFP) cells co-cultured with monocytes-differentiated macrophage enhanced PD-L1 expression in GBM cells. The enhancement of PD-L1 in GBM was antagonized by paliperidone and risperidone as well as DRD2 selective inhibitor L741426. The expression of CD206 (M2 phenotype marker) was observed to be markedly increased in bone marrow-derived macrophages (BMDMs) co-cultured with GBM. Importantly, treatment with paliperidone effectively decreased CD206 and also dramatically increased CD80 (M1 phenotype marker) in BMDMs. We have previously established a PD-L1 GBM-GFP cell line that stably expresses PD-L1. Experiments showed that the expressions of CD206 was increased and CD80 was mildly decreased in the BMDMs co-cultured with PD-L1 GBM-GFP cells. On the other hands, knockdown of DRD2 expression in GBM cells dramatically decreased the expression of CD206 but markedly increased CD80 expressions in BMDMs. The present study suggests that DRD2 may be involved in regulating the PD-L1 expression in GBM and the microenvironment of GBM. Our results provide a valuable therapeutic strategy and indicate that treatments combining DRD2 antagonist paliperidone with standard immunotherapy may be beneficial for GBM treatment.

Mitochondrial Heteroplasmy Shifting as a Potential Biomarker of Cancer Progression

Cancer is a serious health problem with a high mortality rate worldwide. Given the relevance of mitochondria in numerous physiological and pathological mechanisms, such as adenosine triphosphate (ATP) synthesis, apoptosis, metabolism, cancer progression and drug resistance, mitochondrial genome (mtDNA) analysis has become of great interest in the study of human diseases, including cancer. To date, a high number of variants and mutations have been identified in different types of tumors, which coexist with normal alleles, a phenomenon named heteroplasmy. This mechanism is considered an intermediate state between the fixation or elimination of the acquired mutations. It is suggested that mutations, which confer adaptive advantages to tumor growth and invasion, are enriched in malignant cells. Notably, many recent studies have reported a heteroplasmy-shifting phenomenon as a potential shaper in tumor progression and treatment response, and we suggest that each cancer type also has a unique mitochondrial heteroplasmy-shifting profile. So far, a plethora of data evidencing correlations among heteroplasmy and cancer-related phenotypes are available, but still, not authentic demonstrations, and whether the heteroplasmy or the variation in mtDNA copy number (mtCNV) in cancer are cause or consequence remained unknown. Further studies are needed to support these findings and decipher their clinical implications and impact in the field of drug discovery aimed at treating human cancer.

Metabolic Drivers of Invasion in Glioblastoma

Glioblastoma is a primary malignant brain tumor with a median survival under 2 years. The poor prognosis glioblastoma caries is largely due to cellular invasion, which enables escape from resection, and drives inevitable recurrence. While most studies to date have focused on pathways that enhance the invasiveness of tumor cells in the brain microenvironment as the primary driving forces behind GBM’s ability to invade adjacent tissues, more recent studies have identified a role for adaptations in cellular metabolism in GBM invasion. Metabolic reprogramming allows invasive cells to generate the energy necessary for colonizing surrounding brain tissue and adapt to new microenvironments with unique nutrient and oxygen availability. Historically, enhanced glycolysis, even in the presence of oxygen (the Warburg effect) has dominated glioblastoma research with respect to tumor metabolism. More recent global profiling experiments, however, have identified roles for lipid, amino acid, and nucleotide metabolism in tumor growth and invasion. A thorough understanding of the metabolic traits that define invasive GBM cells may provide novel therapeutic targets for this devastating disease. In this review, we focus on metabolic alterations that have been characterized in glioblastoma, the dynamic nature of tumor metabolism and how it is shaped by interaction with the brain microenvironment, and how metabolic reprogramming generates vulnerabilities that may be ripe for exploitation.

Cyanidin-3-O-glucoside represses tumor growth and invasion in vivo by suppressing autophagy via inhibition of the JNK signaling pathways

Black bean seed coat extract (BBSCE) contains a high amount of bioactive compounds which can reduce the risk of cancers, but the underlying mechanism remains poorly understood in vivo.