MAGI1-IT1 stimulates proliferation in non-small cell lung cancer by upregulating AKT1 as a ceRNA

Cell-free DNA 5-hydroxymethylcytosine profiles of long non-coding RNA genes enable early detection and progression monitoring of human cancers

BACKGROUND

5-Hydroxymethylcytosine (5hmC) is a significant DNA epigenetic modification. However, the 5hmC modification alterations in genomic regions encoding long non-coding RNA (lncRNA) and their clinical significance remain poorly characterized.

RESULTS

A three-phase discovery-modeling-validation study was conducted to explore the potential of the plasma-derived 5hmC modification level in genomic regions encoding lncRNAs as a superior alternative biomarker for cancer diagnosis and surveillance. Genome-wide 5hmC profiles in the plasma circulating cell-free DNA of 1632 cancer and 1379 non-cancerous control samples from different cancer types and multiple centers were repurposed and characterized. A large number of altered 5hmC modifications were distributed at genomic regions encoding lncRNAs in cancerous compared with healthy subjects. Furthermore, most 5hmC-modified lncRNA genes were cancer-specific, with only a relatively small number of 5hmC-modified lncRNA genes shared by various cancer types. A 5hmC-LncRNA diagnostic score (5hLD-score) comprising 39 tissue-shared 5hmC-modified lncRNA gene markers was developed using elastic net regularization. The 5hLD-score was able to accurately distinguish tumors from healthy controls with an area under the curve (AUC) of 0.963 [95% confidence interval (CI) 0.940-0.985] and 0.912 (95% CI 0.837-0.987) in the training and internal validation cohorts, respectively. Results from three independent validations confirmed the robustness and stability of the 5hLD-score with an AUC of 0.851 (95% CI 0.786-0.916) in Zhang's non-small cell lung cancer cohort, AUC of 0.887 (95% CI 0.852-0.922) in Tian's esophageal cancer cohort, and AUC of 0.768 (95% CI 0.746-0.790) in Cai's hepatocellular carcinoma cohort. In addition, a significant association was identified between the 5hLD-score and the progression from hepatitis to liver cancer. Finally, lncRNA genes modified by tissue-specific 5hmC alteration were again found to be capable of identifying the origin and location of tumors.

CONCLUSION

The present study will contribute to the ongoing effort to understand the transcriptional programs of lncRNA genes, as well as facilitate the development of novel invasive genomic tools for early cancer detection and surveillance.

A New Story of the Three Magi: Scaffolding Proteins and lncRNA Suppressors of Cancer

Scaffolding molecules exert a critical role in orchestrating cellular response through the spatiotemporal assembly of effector proteins as signalosomes. By increasing the efficiency and selectivity of intracellular signaling, these molecules can exert (anti/pro)oncogenic activities. As an archetype of scaffolding proteins with tumor suppressor property, the present review focuses on MAGI1, 2, and 3 (membrane-associated guanylate kinase inverted), a subgroup of the MAGUK protein family, that mediate networks involving receptors, junctional complexes, signaling molecules, and the cytoskeleton. MAGI1, 2, and 3 are comprised of 6 PDZ domains, 2 WW domains, and 1 GUK domain. These 9 protein binding modules allow selective interactions with a wide range of effectors, including the PTEN tumor suppressor, the β-catenin and YAP1 proto-oncogenes, and the regulation of the PI3K/AKT, the Wnt, and the Hippo signaling pathways. The frequent downmodulation of MAGIs in various human malignancies makes these scaffolding molecules and their ligands putative therapeutic targets. Interestingly, MAGI1 and MAGI2 genetic loci generate a series of long non-coding RNAs that act as a tumor promoter or suppressor in a tissue-dependent manner, by selectively sponging some miRNAs or by regulating epigenetic processes. Here, we discuss the different paths followed by the three MAGIs to control carcinogenesis.

The Long Noncoding RNA MAGI1-IT1 Regulates the miR-302d-3p/IGF1 Axis to Control Gastric Cancer Cell Proliferation

Background

MAGI1-IT1 is a long non-coding RNA (lncRNA) previously reported to regulate several cancer types, but its functional role in gastric cancer (GC) remains to be defined. This study therefore explored the mechanistic role played by MAGI1-IT1 in the regulation of GC cell proliferation.

Methods

120 pairs of GC patient tumor, paracancerous tissues, human GES-1 control cells and human AGS, MKN-74, MKN-45, and MGC-803 GC cell lines were used to detected MAGI1-IT1, miR-302d-3p, and IGF1 expression by a qPCR approach. An shRNA approach was used to knock down MGI1-IT1 in order to examine the effect of such treatment on GC cell proliferation, and rescue experiments were subsequently conducted. In addition, the functional role of MAGI1-IT1 in GC in vivo was evaluated with a xenograft model system. P < 0.05 was the significance threshold.

Results

Elevated MAGI1-IT1 expression was detected in GC cell lines and tissues, and was linked to poorer patient overall survival. Knocking down this lncRNA disrupted GC cell proliferation in vitro and in vivo, and miR-302d-3p was identified as a MAGI1-IT1 target. Notably, miR-302d-3p inhibition partially reversed the impact of MAGI1-IT1 knockdown on GC cell proliferation. IGF1 was subsequently identified as a miR-302d-3p target gene that was upregulated by MAGI1-IT1 through miR-302d-3p.

Conclusion

Overall, these results indicated that MAGI1-IT1 controlled GC cell proliferation by modulating the miR-302d-3p/IGF1 axis, suggesting that this may be a viable treatment target in those with GC.

High mobility group box 2 modulates the progression of osteosarcoma and is related with poor prognosis

Background

Increased expression of high mobility group box 2 (HMGB2) has been reported to promote the progression of several malignancies and be related to poor outcome. However, few studies have explored the relationship between HMGB2 and osteosarcoma. In this study, we aimed to obtain a better understanding of HMGB2 and its function in osteosarcoma.

Methods

Utilizing osteosarcoma paraffin sections and osteosarcoma cell lines, we observed the clinico-pathological relationship of osteosarcoma with HMGB2 expression and investigated the functions of HMGB2 in vitro. The possible pathways and regulation networks in which HMGB2 is involved were further explored through analysis of miRNA, mRNA and lncRNA micro array data sets.

Results

Strong expression of HMGB2 was found to be related with Enneking staging (P=0.002), tumor size (P=0.006), metastasis (P<0.001), and survival (P=0.011) in osteosarcoma. Multivariate analysis revealed that HMGB2 might have independent prognostic value in osteosarcoma (P=0.022). Kaplan-Meier curves and the log-rank test showed that survival time was significantly reduced in OS patients with strong HMGB2 expression (P=0.0056). In vitro experiments showed that HMGB2 overexpression promoted cell proliferation and enhanced the migration and invasion ability of osteosarcoma cells. Gene Ontology (GO) term analysis of osteosarcoma cell lines revealed HMGB2 to have various functions and to be mainly enriched in regulation of cell proliferation, cell death, and DNA binding. A competing endogenous RNA (ceRNA) network of miR-139-5p and six candidate lncRNAs was also suggested as targeting HMGB2 in osteosarcoma.

Conclusions

Our findings suggest that HMGB2 might have various functions in promoting the progression of osteosarcoma and may serve as a new target for osteosarcoma research.