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Gene & Protein in Disease circRNAs and cancer

2.5. HCC found a significant association between circRNAs with low

Increasing evidence in scientific literatures implicate expression and the development of GBM through ErbB
[69]
circRNAs in the development and progression of HCC, and neurotrophin signaling pathways . Besides, common
leading to a poor prognosis for HCC patients. For example, expression of circBRAF has been identified in glioma
[68]
in comparison with neighboring normal liver tissue samples, patients with high-grade tumors . However, circTTBK2
hsa_circ_0001649 was significantly suppressed in 89 HCC has a higher expression in glioma tissues. Its effect is induced
tissue samples. In HCC, its expression was associated with by impairing miR-217 and elevating HNF1β expression,
both the size of the tumor and the tumor embolus, and which subsequently binds to Derlin-1 oncogene, thereby
knocking down the circRNA increased the mRNA level of increasing its promoter activity and upregulating the
matrix metallopeptidases (MMPs), promoting the spread cell proliferation, migration, and apoptotic repression
[70]
of HCC . Similar circZKSCAN1 and its linear analog were by targeting PI3K/Akt and ERK signaling pathways .
[61]
suppressed in HCC tissues. Increased tumor size, cirrhosis, Similarly, hsa_circ_0000177 also causes an increased
metastasis, and poor prognosis were linked to reduced expression of glioma tissues, which is linked to the poor
expression of circZKSCAN1. Through several signaling prognosis of patients. The silenced hsa_circ_0000177 acts
pathways, the upregulation of circZKSCAN1 and its linear as a miR-638 sponge to drastically reduce cell growth and
mRNA can significantly prevent the growth and metastasis metastasis. This causes the frizzled class receptor 7 (FZD7)
of HCC . However, high expression of circRHOT1 (hsa_ to be upregulated, further regulating Wnt signaling and
[62]
[71]
circRNA_102034) in HCC tissue samples is associated enhancing glioma cell development . CircMMP9 also
[63]
with poor prognosis . hsa_circ_100084 was more highly has high expression in glioma cancer. Through miR-124
expressed in HCC clinical samples than in samples of sponging, increased expression of circMMP9 regulates
healthy liver tissue. Sponging miR-23a-5p functions as a CDK4 and Aurora kinase A (AURKA), and glioblastoma
ceRNA to increase IGF2 expression, enhancing HCC cell multiforme cells are driven to proliferate, migrate, and
[72]
proliferation, invasion, and relocation . Recently, Sun invade . Moreover, circPRKCI is overexpressed in glioma
[64]
et al. observed three circRNAs (hsa_circ_0004001, hsa_ tissues and significantly stimulates miR-545, inhibiting
[31]
circ_0004123, and hsa_circ_0075792) upregulated and cancer growth, survival, multiplication, and relocation .
positively correlated with tumor size and TNM stage in the Similarly, circ_001350 is highly expressed in tissue samples
blood of HCC patients. The underlying mechanism was and cells from glioma patients, and by interacting with
the regulation of 35 distinct miRNAs by the Akt/mTOR, miR-1236, it reduces cell growth and metastasis while
[73]
VEG, and Wnt signaling pathways . promoting apoptosis . Circ-MAPK4 (hsa_circ_0047688)
[65]
upregulated and associated with a pathogenic form of
2.6. Gliomas gliomas, has been shown to impede the apoptosis of glioma
Gliomas are a vast category of nervous system tumors cells by acting as a sponge of miR-125a-3p and regulating
[74]
and one of the most prevalent malignancies with a poor p38/MAPK signaling pathway .
prognosis globally. Recent studies have revealed the 2.7. Pancreatic ductal adenocarcinoma (PDAC)
transcription of circRNAs in mammalian brains and their
role in the growth and spread of gliomas . A total of 476 More than 85% of cases of pancreatic cancer are caused by
[66]
circRNAs with differential expression have been found in PDAC, which is also one of the main causes of death and
[75]
46 GBM and normal brain tissue samples, among which poor prognosis globally . Numerous circRNAs that are
468 circRNAs were more upregulated in normal brain overexpressed in PDAC have been identified. It is crucial
tissue than GBM tissues. Furthermore, eight circRNAs, to find these circRNAs that express differently to better
including circCOL1A2, circPTN, circVCAN, circSMO, comprehend PDAC. In PDAC cancer patient samples, Li
circPLOD2, circGLIS3, circEPHB4, and circCLIP2, et al. discovered seven circRNAs using circRNA microarray
had significantly higher expression in glioblastoma analysis, of which two had upregulated expression levels and
multiforme (GBM) samples compared to normal human the remaining five had downregulated expression levels .
[76]
tissues, raising the possibility that they could be used as A total of 278 circRNAs were differentially expressed in
biomarkers for the disease . The oncogenic circRNA, PDAC tissues according to RNA sequencing and circRNA
[67]
cZNF292, influences the development of tube formation. expression analysis. Among these, hsa_circ_0007334 was
By controlling the Wnt/beta-catenin biochemical strongly upregulated and acts as a ceRNA by binding to
pathway, the suppression of cZNF292 prevents glioma cell miR-144-3p and miR-577, which boosted the expression
proliferation, progression, and tube formation . Another and functionality of MMP7 and collagen type I alpha 1
[68]
study determined differentially expressed (206 upregulated chain (COL1A1) in PDAC . Likewise, pancreatic cancer
[77]
and 1205 downregulated) circRNAs in GBM patients and (PC) tissues had higher levels of circLDLRAD3, which

Volume 1 Issue 2 (2022) 4 https://doi.org/10.36922/gpd.v1i2.138