Up-regulation of Circular RNA hsa_circ_01844 Induces Apoptosis and Suppresses Proliferation and Migration of Glioblastoma Cells
Glioblastoma, the most aggressive subtype of glioma, is the most common primary malignancy of the central nervous system. Despite advances in surgical and chemoradiotherapeutic treatments, the prognosis for glioblastoma patients remains poor, with a median survival of only 14 to 17 months. The aggressive nature of glioblastoma is attributed to its complex pathogenesis, which makes it resistant to conventional therapies. Consequently, understanding the mechanisms underlying glioblastoma progression and identifying novel therapeutic targets are critical for improving patient outcomes.
Circular RNAs (circRNAs) are a class of non-coding RNAs characterized by their covalently closed loop structure. Recent studies have highlighted their roles in various physiological and pathological processes, including cancer progression. CircRNAs can function as microRNA (miRNA) sponges, sequestering miRNAs and thereby modulating the expression of downstream target genes. This regulatory mechanism has been implicated in the pathogenesis of several cancers, including liver, lung, and breast cancers. However, the role of circRNAs in glioblastoma remains poorly understood.
This study focuses on the circRNA hsa_circ_01844, which was previously identified as having significantly lower expression in glioblastoma tissues compared to normal brain tissues. The aim of this research was to investigate the functional role of hsa_circ_01844 in glioblastoma, particularly its effects on cell proliferation, migration, invasion, and apoptosis.
Expression of hsa_circ_01844 in Glioblastoma Tissues
The study began by measuring the expression levels of hsa_circ_01844 in glioblastoma tissues and normal brain tissues using reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that hsa_circ_01844 expression was significantly lower in glioblastoma tissues (0.034 ± 0.036) compared to normal brain tissues (1.630 ± 0.891), with a p-value of less than 0.001. This finding suggests that hsa_circ_01844 may function as a tumor suppressor in glioblastoma.
Overexpression of hsa_circ_01844 in Glioblastoma Cell Lines
To explore the functional role of hsa_circ_01844, the researchers overexpressed this circRNA in two glioblastoma cell lines, U87 and U251, using a lentivirus vector. The overexpression was confirmed through RT-PCR. The effects of hsa_circ_01844 overexpression on cell proliferation, migration, invasion, and apoptosis were then evaluated using a series of in vitro assays.
Inhibition of Cell Proliferation and Colony Formation
The impact of hsa_circ_01844 overexpression on cell proliferation was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that overexpression of hsa_circ_01844 significantly inhibited the growth of both U87 and U251 cells compared to the empty vector and blank control groups (p < 0.001).
Additionally, colony formation assays were performed to evaluate the long-term effects of hsa_circ_01844 on cell proliferation. The results demonstrated that cells overexpressing hsa_circ_01844 formed significantly fewer colonies than the control groups (p < 0.01). These findings indicate that hsa_circ_01844 suppresses the proliferative capacity of glioblastoma cells.
Inhibition of Cell Cycle Progression
Flow cytometry was used to analyze the cell cycle distribution in U87 and U251 cells overexpressing hsa_circ_01844. The results revealed a significant reduction in the proportion of cells in the G2 phase in the hsa_circ_01844 overexpression group compared to the control groups (p < 0.05). This suggests that hsa_circ_01844 inhibits cell cycle progression, thereby contributing to its anti-proliferative effects.
Suppression of Cell Migration and Invasion
The effects of hsa_circ_01844 on cell migration were evaluated using the Transwell assay. Overexpression of hsa_circ_01844 led to a significant decrease in the migratory ability of both U87 and U251 cells compared to the control groups (p < 0.001). This indicates that hsa_circ_01844 inhibits the migration of glioblastoma cells, a critical step in tumor metastasis.
Induction of Apoptosis
The role of hsa_circ_01844 in apoptosis was assessed using flow cytometry. The results showed that overexpression of hsa_circ_01844 significantly increased the apoptotic rate in both U87 and U251 cells compared to the control groups (p < 0.001). This suggests that hsa_circ_01844 promotes apoptosis in glioblastoma cells, further supporting its tumor-suppressive function.
Potential Mechanisms of hsa_circ_01844 in Glioblastoma
The study also explored the potential mechanisms through which hsa_circ_01844 exerts its tumor-suppressive effects. Bioinformatics analysis predicted that hsa_circ_01844 may interact with several miRNAs, including miRNA-616 and miRNA-671-5p.
MiRNA-616 has been shown to act as a tumor promoter in glioma by regulating the Sry-related HMG box-7 (SOX7) and Wnt/β-catenin signaling pathways. MiRNA-671-5p, on the other hand, has been reported to inhibit glioblastoma progression by targeting the complementarity determining region 1 (CDR1) pathway.
Based on these findings, it is hypothesized that hsa_circ_01844 functions as a miRNA sponge, sequestering tumor-promoting miRNAs such as miRNA-616 and miRNA-671-5p. This interaction would inhibit the expression of downstream oncogenic targets, thereby suppressing glioblastoma progression.
Clinical Implications
The findings of this study have significant clinical implications. The downregulation of hsa_circ_01844 in glioblastoma tissues suggests that it may serve as a potential diagnostic biomarker for this aggressive cancer. Furthermore, the tumor-suppressive effects of hsa_circ_01844, including its ability to inhibit proliferation, migration, and invasion, as well as to induce apoptosis, highlight its potential as a therapeutic target.
Future research should focus on elucidating the precise molecular mechanisms through which hsa_circ_01844 exerts its effects. This could involve identifying the specific miRNAs and downstream signaling pathways that are regulated by hsa_circ_01844. Additionally, in vivo studies using animal models of glioblastoma would be valuable for validating the therapeutic potential of hsa_circ_01844 overexpression.
Conclusion
In conclusion, this study demonstrates that hsa_circ_01844 is downregulated in glioblastoma tissues and that its overexpression inhibits proliferation, migration, and invasion while promoting apoptosis in glioblastoma cell lines. These findings suggest that hsa_circ_01844 functions as a tumor suppressor in glioblastoma, likely through its interaction with tumor-promoting miRNAs.
The identification of hsa_circ_01844 as a potential therapeutic target offers new hope for the development of effective treatments for glioblastoma. Further research is needed to fully understand the mechanisms underlying its tumor-suppressive effects and to explore its clinical applications.
doi.org/10.1097/CM9.0000000000000979
Was this helpful?
0 / 0