bims-meluca 2019-06-16 papers

Mol Ther Nucleic Acids. 2019 May 18. pii: S2162-2531(19)30125-8. [Epub ahead of print]17 24-37

Metabolic Reprograming Via Silencing of Mitochondrial VDAC1 Expression Encourages Differentiation of Cancer Cells.

The mitochondrial gatekeeper voltage-dependent anion channel 1 (VDAC1) controls metabolic and energy cross-talk between mitochondria and the rest of the cell and is involved in mitochondria-mediated apoptosis. Here, we compared the effects of downregulated VDAC1 expression in the U-87MG glioblastoma, MDA-MB-231 triple-negative breast cancer (TNBC), and A549 lung cancer cell lines, using small interfering RNA (siRNA) specific to human VDAC1 (si-hVDAC1). The cells were subjected to si-hVDAC1 (50 nM) treatment for 5-20 days. Although VDAC1 silencing occurred within a day, the cells underwent reprograming with respect to rewiring metabolism, elimination of cancer stem cells (CSCs), and alteration of transcription factor (TF) expression and proteins associated with differentiation, with maximal changes being observed after 3 weeks of silencing VDAC1 expression. The differentiation into fewer tumorigenic cells may be associated with the elimination of CSCs. These alterations are interconnected, as protein up- or downregulation occurred simultaneously, starting 15-20 days after VDAC1 levels were first decreased. Moreover, the VDAC1 depletion-mediated effects on a network of key regulators of cell metabolism, CSCs, TFs, and other factors leading to differentiation are coordinated and are common to the glioblastoma multiforme (GBM) and lung and breast cancer cell lines, despite differing in origin and carried mutations. Thus, our study showed that VDAC1 depletion triggers reprograming of malignant cancer cells into terminally differentiated cells and that this may be a promising therapeutic approach for various cancers.

Keywords: VDAC1; cancer; cell differentiation; metabolism; mitochondria; siRNA

DOI: https://doi.org/10.1016/j.omtn.2019.05.003

Mol Med Rep. 2019 May 22.

High developmental pluripotency‑associated 4 expression promotes cell proliferation and glycolysis, and predicts poor prognosis in non‑small‑cell lung cancer.

Li L, Wang Y, Wang Q, Qu J, Wei X, Xu J, Wang Y, Suo F, Zhang Y.

The developmental pluripotency‑associated 4 (Dppa4) gene serves critical roles in cell self‑renewal, as well as in cancer development and progression. However, the regulatory role of Dppa4 in non‑small‑cell lung cancer (NSCLC) and its underlying mechanisms remain elusive. The aim of the present study was to investigate the biological function of Dppa4 in NSCLC and its underlying mechanism of action. Dppa4 expression was measured in NSCLC tissue samples and cell lines, and its effect on cell proliferation and the expression of glycolytic enzymes was determined. In addition, the underlying mechanisms of Dppa4‑induced alterations in glycolysis were analyzed. Univariate and multivariate analyses were also performed to analyze the prognostic significance of clinicopathological characteristics. Dppa4 was found to be highly expressed in NSCLC tissues and cell lines. Furthermore, it was observed that Dppa4 was correlated with the degree of tumor differentiation and TNM stage. Univariate and multivariate analyses identified Dppa4 expression and clinical stage as prognostic factors for NSCLC patients. Kaplan‑Meier analysis further revealed that patients with lower Dppa4 expression exhibited a better prognosis. In NSCLC cells, Dppa4 knockdown inhibited cell proliferation, while Dppa4 overexpression enhanced cell proliferation, which was likely mediated by glycolysis promotion. Dppa4 knockdown had no evident effect on the majority of enzymes examined; however, glucose transporter type 4 (GLUT‑4) and pyruvate kinase isozyme M2 were significantly upregulated, and hexokinase II (HK‑II) and lactate dehydrogenase B (LDHB) were downregulated following Dppa4 knockdown. By contrast, Dppa4 overexpression resulted in downregulation of GLUT‑4, and upregulation of HK‑II, enolase and LDHB, whereas it had no effect on other enzymes. Since the most evident effect was observed on LDHB, further functional experiments demonstrated that this enzyme reversed the promoting effects of Dppa4 in NSCLC. In conclusion, Dppa4 promotes NSCLC progression, partly through glycolysis by LDHB. Thus, the Dppa4‑LDHB axis critically contributes to glycolysis in NSCLC cells, thereby promoting NSCLC development and progression.

DOI: https://doi.org/10.3892/mmr.2019.10272

BMB Rep. 2019 Jun 12. pii: 4532. [Epub ahead of print]

ATAD2 expression increases [18F]Fluorodeoxyglucose uptake value in lung adenocarcinoma via AKT-GLUT1/HK2 pathway.

Sun T, Du B, Diao Y, Li X, Chen S, Li Y.

[18F]Fluorodeoxyglucose (FDG) PET/CT imaging has been widely used in the diagnosis of malignant tumors. ATPase family AAA domain-containing protein 2 (ATAD2) plays important roles in tumor growth, invasion and metastasis. However, the relationship between [18F]FDG accumulation and ATAD2 expression remains largely unknown. This study aimed to investigate the correlation between ATAD2 expression and [18F]FDG uptake in lung adenocarcinoma (LUAD), and elucidate its underlying molecular mechanisms. The results showed that ATAD2 expression was positively correlated with maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), glucose transporter type 1 (GLUT1) expression and hexokinase2 (HK2) expression in LUAD tissues. In addition, ATAD2 knockdown significantly inhibited the proliferation, tumorigenicity, migration, [18F]FDG uptake and lactate production of LUAD cells, while, ATAD2 overexpression exhibited the opposite effects. Furthermore, ATAD2 modulated the glycometabolism of LUAD via AKT-GLUT1/HK2 pathway, as assessed using LY294002 (an inhibitor of PI3K/AKT pathway). In summary, to explore the correlation between ATAD2 expression and glycometabolism is expected to bring good news for anti-energy metabolism therapy of cancers.

J Oncol. 2019 ;2019 2476175

Low Long Noncoding RNA Growth Arrest-Specific Transcript 5 Expression in the Exosomes of Lung Cancer Cells Promotes Tumor Angiogenesis.

Cheng Y, Dai X, Yang T, Zhang N, Liu Z, Jiang Y.

Angiogenesis plays a key role in the development and progression of lung cancer. Recent studies have found that tumor cells can stimulate angiogenesis by secreting exosomes, which contain many long noncoding RNAs (lncRNAs), some of which are important for the development of lung cancer. However, the roles and mechanisms of exosomal lncRNAs in lung cancer angiogenesis have not yet been reported. In this study, lung cancer in mice was induced by urethane; we found that growth arrest specific 5 (GAS5) was lowly expressed in the serum exosomes and lung cancer tissues of mice with lung cancer. And there was a significant positive correlation between GAS5 expression in serum exosomes and lung cancer tissues. Furthermore, GAS5 was lowly expressed in human lung cancer tissues, lung cancer cells, and cells culture supernatant exosomes. The exosomes of lung cancer cells promoted human umbilical vein endothelial cells (HUVECs) proliferation and tube formation and inhibited their apoptosis. GAS5 overexpression in lung cancer cells increased GAS5 level in cell culture supernatant exosomes. And the exosomes of lung cancer cells containing high GAS5 level inhibited HUVECs proliferation and tube formation and increased their apoptosis. In addition, we found that GAS5 competitively bound miRNA-29-3p with phosphatase and tensin homolog (PTEN), upregulating PTEN mRNA and protein expression, and inhibited level of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PI3K) and serine/threonine kinase 1 (AKT) phosphorylation in HUVECs. Overall, our results suggest that exosomal GAS5 could be a new therapeutic target for lung cancer which inhibits angiogenesis.

DOI: https://doi.org/10.1155/2019/2476175