Identification of DRG-1 As a Melanoma-Associated Antigen Recognized by CD4+ Th1 Cells

Structure and function of cancer-related developmentally regulated GTP-binding protein 1 (DRG1) is conserved between sponges and humans

Cancer is a disease caused by errors within the multicellular system and it represents a major health issue in multicellular organisms. Although cancer research has advanced substantially, new approaches focusing on fundamental aspects of cancer origin and mechanisms of spreading are necessary. Comparative genomic studies have shown that most genes linked to human cancer emerged during the early evolution of Metazoa. Thus, basal animals without true tissues and organs, such as sponges (Porifera), might be an innovative model system for understanding the molecular mechanisms of proteins involved in cancer biology. One of these proteins is developmentally regulated GTP-binding protein 1 (DRG1), a GTPase stabilized by interaction with DRG family regulatory protein 1 (DFRP1). This study reveals a high evolutionary conservation of DRG1 gene/protein in metazoans. Our biochemical analysis and structural predictions show that both recombinant sponge and human DRG1 are predominantly monomers that form complexes with DFRP1 and bind non-specifically to RNA and DNA. We demonstrate the conservation of sponge and human DRG1 biological features, including intracellular localization and DRG1:DFRP1 binding, function of DRG1 in α-tubulin dynamics, and its role in cancer biology demonstrated by increased proliferation, migration and colonization in human cancer cells. These results suggest that the ancestor of all Metazoa already possessed DRG1 that is structurally and functionally similar to the human DRG1, even before the development of real tissues or tumors, indicating an important function of DRG1 in fundamental cellular pathways.

ZC3H15 Correlates with a Poor Prognosis and Tumor Progression in Melanoma

Zinc figure CCCH-type containing 15 (ZC3H15), also called developmentally regulated GTP-binding protein 1 (DRG1) family regulatory protein 1 (DFRP1), is a zinc finger containing protein. Despite playing a role in cellular signaling, it is found overexpressed in acute myeloid leukemia and also an independent prognostic marker in hepatocellular carcinoma patients. However, the biological effect of ZC3H15 in malignant melanoma (MM) remains unexplored. The expression of ZC3H15 in patients was analyzed using the R2: Genomics Analysis and Visualization Platform database. Immunohistochemical analysis, western blot, and qRT-PCR were used to detect ZC3H15 expression in melanoma tissues and cell lines. MTT, BrdU, flow cytometry assay, transwell, and western blot were performed to explore the proliferation, cell cycle, invasion, and migration of melanoma cells. We undertaken colony formation assay in vitro and tumor xenograft in vivo to detect the tumorigenicity of melanoma cells. In the present study, ZC3H15 was demonstrated highly expressed in melanoma tissues and cells. Elevated ZC3H15 impairs the survival of melanoma patients. Meanwhile, attenuation of ZC3H15 in melanoma cells inhibited cell proliferation and induced cycle arrest at G0/G1 phase. Consistently, the expression of cell cycle-related proteins cyclin dependent kinase 4 (CDK4), CDK6, and cyclin D1 (CCND1) was decreased while p21 was upregulated. Furthermore, we found the migration and invasion abilities were inhibited in ZC3H15-knockdown melanoma cells. In addition, downregulation of ZC3H15 resulted in inhibition of colony formation abilities in vitro and tumorigenesis in vivo. ZC3H15 promotes proliferation, migration/invasion, and tumorigenicity of melanoma cells. As a promising biomarker and therapeutic target in MM, ZC3H15 is worthy of further exploration.

Developmentally regulated GTPases: structure, function and roles in disease

GTPases are a large superfamily of evolutionarily conserved proteins involved in a variety of fundamental cellular processes. The developmentally regulated GTP-binding protein (DRG) subfamily of GTPases consists of two highly conserved paralogs, DRG1 and DRG2, both of which have been implicated in the regulation of cell proliferation, translation and microtubules. Furthermore, DRG1 and 2 proteins both have a conserved binding partner, DRG family regulatory protein 1 and 2 (DFRP1 and DFRP2), respectively, that prevents them from being degraded. Similar to DRGs, the DFRP proteins have also been studied in the context of cell growth control and translation. Despite these proteins having been implicated in several fundamental cellular processes they remain relatively poorly characterized, however. In this review, we provide an overview of the structural biology and biochemistry of DRG GTPases and discuss current understanding of DRGs and DFRPs in normal physiology, as well as their emerging roles in diseases such as cancer.

m6A-dependent up-regulation of DRG1 by METTL3 and ELAVL1 promotes growth, migration, and colony formation in osteosarcoma

Osteosarcoma (OS) is a malignant tumor commonly observed in children and adolescents. Developmentally regulated GTP-binding protein (DRG) 1 plays an important role in embryonic development; aberrantly expressed DRG1 has been associated with pathological processes in cancer. The present study aimed to explore the role of DRG1 in OS and the mechanisms underlying DRG1 overexpression in OS. Clinical studies were performed to evaluate Drg1 expression in OS tissues and to identify a correlation between Drg1 expression and the clinicopathological features in patients with OS. Drg1 was knocked down in OS cells to determine its effects on cell viability, cell cycle distribution, apoptosis, migration, invasion, and colony formation rate. METTL3 and ELAVL1 were also silenced to determine their effects on the levels of N6-methyladenosine (m6A), RNA stability, and Drg1 expression. Higher levels of Drg1 mRNA and protein were observed in OS tissues than those in paracancerous tissues. High expression of DRG1 was associated with large tumor size and advanced clinical stages in OS. Silencing of Drg1 resulted in decreased viability and inhibition of the migration and colony formation abilities of OS cells; it also resulted in cell cycle arrest in the G₂/M stage and induced apoptosis. Knockdown of METTL3 led to decreased m6A and Drg1 mRNA levels. ELAVL1 knockdown impaired the stability of DRG1 mRNA, thereby reducing both the mRNA and protein levels of DRG1. In all, DRG1 exerted tumorigenic effects in OS, and the up-regulation of DRG1 in OS was induced by METTL3 and ELAVL1 in an m6A-dependent manner.

The Inducing Roles of the New Isolated Bursal Hexapeptide and Pentapeptide on the Immune Response of AIV Vaccine in Mice

BACKGROUND

Bursa of Fabricius is the acknowledged central humoral immune organ. The bursal-derived peptides play the important roles on the immature B cell development and antibody production.

OBJECTIVES

Here we explored the functions of the new isolated bursal hexapeptide and pentapeptide on the humoral, cellular immune response and antigen presentation to Avian Influenza Virus (AIV) vaccine in mice immunization.

METHODS

The bursa extract samples were purified following RP HPLC method, and were analyzed with MS/MS to identify the amino acid sequences. Mice were twice subcutaneously injected with AIV inactivated vaccine plus with two new isolated bursal peptides at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from the immunized mice to measure AIV-specific IgG antibody levels and HI antibody titers. Also, on 7th day after the second immunization, lymphocytes were isolated from the immunized mice to detect T cell subtype and lymphocyte viabilities, and the expressions of co-stimulatory molecule on dendritic cells in the immunized mice.

RESULTS

Two new bursal hexapeptide and pentapeptide with amino acid sequences KGNRVY and MPPTH were isolated, respectively. Our investigation proved the strong regulatory roles of bursal hexapeptide on AIV-specific IgG levels and HI antibody titers, and lymphocyte viabilities, and the significant increased T cells subpopulation and expressions of MHCII molecule on dendritic cells in the immunized mice. Moreover, our findings verified the significantly enhanced AIV-specific IgG antibody and HI titers, and the strong increased T cell subpopulation and expressions of CD40 molecule on dendritic cells in the mice immunized with AIV vaccine and bursal pentapeptide.

CONCLUSION

We isolated and identified two new hexapeptide and pentapeptide from bursa, and proved that these two bursal peptides effectively induced the AIV-specific antibody, T cell and antigen presentation immune responses, which provided an experimental basis for the further clinical application of the bursal derived active peptide on the vaccine improvement.

DRG1 is a potential oncogene in lung adenocarcinoma and promotes tumor progression via spindle checkpoint signaling regulation

Developmentally regulated GTP binding protein 1 (DRG1), a member of the DRG family, plays important roles in regulating cell growth. However, the molecular basis of DRG1 in cell proliferation regulation and the relationship between DRG1 and tumor progression remain poorly understood. Here, we demonstrate that DRG1 is elevated in lung adenocarcinomas while weakly expressed in adjacent lung tissues. DRG1 knockdown causes growth inhibition of tumor cells by significantly increasing the proportion of cells in M phase. Overexpression of DRG1 leads to chromosome missegregation which is an important index for tumorigenesis. Interestingly, ectopic of DRG1 reduces taxol induced apoptosis of lung adenocarcinoma cells. Mechanistic analyses confirm that DRG1 localizes at mitotic spindles in dividing cells and binds to spindle checkpoint signaling proteins in vivo. These studies highlight the expanding role of DRG1 in tumorigenesis and reveal a mechanism of DRG1 in taxol resistance.

Curcumin up regulates T helper 1 cells in patients with colon cancer

The therapy for the advanced colon cancer (Cca) is unsatisfactory currently. To regulate the immune effector cell function has shown a positive effect on the treatment of advanced cancers. This study tests a hypothesis that administration with curcumin converts the Cca patient-derived regulatory T cells (Treg) to T helper (Th) 1 cells. In this study, a group of patients with advanced Cca was recruited into this study. The patients were treated with curcumin. The peripheral Tregs and Th1 cells were assessed by flow cytometry. The results showed that, after the curcumin therapy, the forkhead box protein (Foxp) 3 positive Treg frequency was markedly reduced, the frequency of Th1 cells was significantly increased in Cca patients. Treating with curcumin repressed the Foxp3 gene transcription in Tregs; the Tregs were then converted into Th1 cells. The results also revealed that Foxp3 bound T-bet to prevent IFN-γ expression in CD4⁺ T cells, which was abolished by treating with curcumin. In conclusion, the administration of curcumin can convert Tregs to Th1 cells via repressing Foxp3 expression and enhancing IFN-γ production.

Evaluation of autoantibody signatures in meningioma patients using human proteome arrays

Meningiomas are one of the most common tumors of the Central nervous system (CNS). This study aims to identify the autoantibody biomarkers in meningiomas using high-density human proteome arrays (~17,000 full-length recombinant human proteins). Screening of sera from 15 unaffected healthy individuals, 10 individuals with meningioma grade I and 5 with meningioma grade II was performed. This comprehensive proteomics based investigation revealed the dysregulation of 489 and 104 proteins in grades I and II of meningioma, respectively, along with the enrichment of several signalling pathways, which might play a crucial role in the manifestation of the disease. Autoantibody targets like IGHG4, CRYM, EFCAB2, STAT6, HDAC7A and CCNB1 were significantly dysregulated across both the grades. Further, we compared this to the tissue proteome and gene expression profile from GEO database. Previously reported upregulated proteins from meningioma tissue-based proteomics obtained from high-resolution mass spectrometry demonstrated an aggravated autoimmune response, emphasizing the clinical relevance of these targets. Some of these targets like SELENBP1 were tested for their presence in tumor tissue using immunoblotting. In the light of highly invasive diagnostic modalities employed to diagnose CNS tumors like meningioma, these autoantibody markers offer a minimally invasive diagnostic platform which could be pursued further for clinical translation.