Functional role of MicroRNA/PI3K/AKT axis in osteosarcoma

Abstract

Osteosarcoma (OS) is a primary malignant bone tumor that occurs in children and adolescents, and the PI3K/AKT pathway is overactivated in most OS patients. MicroRNAs (miRNAs) are highly conserved endogenous non-protein-coding RNAs that can regulate gene expression by repressing mRNA translation or degrading mRNA. MiRNAs are enriched in the PI3K/AKT pathway, and aberrant PI3K/AKT pathway activation is involved in the development of osteosarcoma. There is increasing evidence that miRNAs can regulate the biological functions of cells by regulating the PI3K/AKT pathway. MiRNA/PI3K/AKT axis can regulate the expression of osteosarcoma-related genes and then regulate cancer progression. MiRNA expression associated with PI3K/AKT pathway is also clearly associated with many clinical features. In addition, PI3K/AKT pathway-associated miRNAs are potential biomarkers for osteosarcoma diagnosis, treatment and prognostic assessment. This article reviews recent research advances on the role and clinical application of PI3K/AKT pathway and miRNA/PI3K/AKT axis in the development of osteosarcoma.

Keywords: MicroRNA; PI3K/AKT pathway; biomarker; mechanism; osteosarcoma.

Figure 1

(A) Representative images of the transwell invasion assays and wound healing assays are shown for each group (85). (B) Overexpression of CHRDL2 promoted osteosarcoma cell proliferation and mobility. (a) Wound healing assay. (b) Transwell assay (86). (C) COX-2 overexpression increases migration and invasion in MG-63 cells (87). (D) The role of HER4 in the PI3K/mTOR signaling pathway. (D-a) The western blotting was used to measure the protein expression of p-PI3K, p-AKT, and p-PTEN. (D-b) Wound healing assay was performed to measure the migration ability of cells (88).

Figure 2

(A) Proliferation rates of MG63/U2OS cells among the control, NC-siRNA and Ski-siRNA groups at 24 and 48 h following transfection (62). (B) Cell cycle profiles determined by propidium iodide (PI) staining and flow cytometry assays of (a) MNNG/HOS and (b) U2OS cells transfected with si-SLC3A2 or si-NC (96). (C) Flow cytometric analysis of the percentage of cells in different phases of the cell cycle with three independent experiments (97). (D) Following SC treatment, cell cycle distribution was determined by flow cytometry at 24 h (98). (E) ISL treatment induces apoptosis in U2OS cells (63). (F) The apoptotic rates of HOS and MG-63 cells were detected by Annexin V/PI double-staining assay (99). *p < 0.05, **p < 0.01.

Figure 3

(A) After being cocultured using CHE with DOX or MTX, apoptosis was measured by performing Annexin V-FITC/PI double staining followed by flow cytometry assay (124). (B) The apoptosis ratios for each group (percentage of Annexin V+ cells) were determined by flow cytometry (125). (C) The protein levels of the EMT markers, E-cadherin, N-cadherin, MMP-9, p-AKT, and AKT in transfected cells were detected by Western blot (126). (D) Overexpression of AIM2 inhibits osteosarcoma cell invasion, migration and EMT. (A) Western blotting was used to assess the levels of EMT-related proteins, including N-cadherin, Vimentin and E-cadherin. (B) Wound healing assay was utilized to detect cell migration (61). (E) ZCCHC12 promoted OS cell EMT progression, qRT-PCR (A, B) and western blot analysis (C) were performed to examine EMT-related markers in OS cells after ZCCHC12 knockdown or overexpression (104). *p < 0.05; **p < 0. 01; ***p < 0.001; ****p < 0.0001.

Figure 4

(A) Effect of fibulin-4 knockdown and overexpression on the migration and invasion of the differently invasive osteosarcoma cell subclones (135). (B) MNAT1 regulated OS chemo-sensitivity to DDP-based therapy (136). (C) Tumor weight in each group (54). (D) Cisplatin in synergy with ZA inhibited osteoclast formation, survival, and activation. (a) The TRAP staining of BMMs treated with M-CSF and RANKL for 4 days in the presence of cisplatin/ZA+cisplatin. (b) The mature osteoclasts were treated by cisplatin/ZA+cisplatin. (c) The bone resorption on Corning Osteo Assay 24-well plates of osteoclasts treated by cisplatin/ZA+cisplatin (65). (E) Colony formation capacity of osteosarcoma cells (97). (F) ROCK2 affects the level of glycolysis in OS cells. Extracellular acidification rate data revealed the glycolytic rate and capacity (137). (G) Tumor growth in mouse xenograft models. MG-63 cells infected with NC, miR-26a, or anti-miR-26a lentivirus were injected subcutaneously into nude mice (138). *p < 0.05, **p < 0.01.

Figure 5

The formation process of miRNA.

Figure 6

(A) Roles of miR-133b in invasion and migration of osteosarcoma cell lines. Over-expression of miR-133b suppressed cell invasion and migration in U2-OS cells. Cell invasion and migration were visualized and examined by inverted phase contrast microscope (198). (B) MiR-134 overexpression inhibits the proliferation of Saos-2 cells and their secretion of angiogenesis factors in vitro, but promotes Saos-2 cell apoptosis (183). (C) Serum levels of miR-21 increase as the T stage of osteosarcoma increases (166). (D) ROCK1 rescues cell proliferation and invasion in miR-139 overexpression OS cells. Representative images of transwell invasion assay (197). (E) Representative results of cell migration and invasion assays (189). (F) MG-63 (a) and 143 (b) cells are transfected with Control + miR-NC, miR-524 mimic + Control, PTEN + miR-NC or miR-524 mimic + PTEN, and cell proliferation in each group is detected by CCK-8 (217). ^†P < 0.05; *P < 0.01; **P < 0.001, ^#P < 0.0001.

Figure 7

(A) Cell cycle analysis of Saos-2 and MNNG/HOS cells after transfection with pre/anti-miR-199a-5p or the corresponding control (221). (B) Knockdown of miR-17 inhibited cell proliferation, migration and invasion in OS cells.(a) Cell migration was detected using Transwell assay. (b) Flow cytometry demonstrated that knockdown of miR-17 induced cell apoptosis (220). (C) MiR-23b-3p promoted the cell viability, proliferation and migration in OS. (A) Cell viability was detected by CCK-8 assay. (B) The effect of miR-23b-3p on cell proliferation was detected by BrdU-ELISA. (C) Wound healing assays (184). *p < 0.05, **p < 0.01.