ABSTRACT
Circular RNAs (circRNAs) are a novel class of long-chain non-coding RNAs. Preceding evidence has showed that circRNAs participate in the development and progression of various tumors. In the present study, we investigated the expression of circRNAs in 5 paired colorectal cancer (CRC) tissues and adjacent normal tissues with circRNA high-throughput sequencing. Totally 477 differentially expressed circRNAs were identified between CRC tissues and non-cancerous matched tissues, which included 252 significantly overexpressed circRNAs and 225 downregulated circRNAs. CircRNA plasmacytoma variant translocation 1 (circPVT1), the most up-regulated expression circRNA, was further confirmed by qRT-PCR in 150 colorectal cancer tissues and matched normal mucosae. Our data revealed that circPVT1 showed a significant up-regulation trend in CRC tissues compared with matched normal mucosae. Similarly, compared with normal colorectal mucosa cells, the expression of circPVT1 in colorectal cancer cell lines was significantly up-regulated (P<0. 05). Functionally, silence with siRNA or overexpression of circPVT1 in colorectal cancer cells was applied to determine the biological functions of circPVT1, including cell proliferation, apoptosis, and cell cycle, etc. The results show that circPVT1 expression significantly attenuated apoptosis, induced replication and promoted proliferation of colorectal cancer cells in vitro. In summary, our findings indicate that circPVT1 plays an oncogenic role in CRC and might be a potential novel target for CRC therapy.
ABSTRACT
<p><b>OBJECTIVE</b>To study DNA damage, Bcl-2 and Bax expression, and ultrastructure change in spermatogenic cell of mice by cadmium exposure.</p><p><b>METHODS</b>Twenty-four male mice were divided into 4 groups: 3 groups treated with cadmium chloride of 1, 5, 10 micromol x kg(-1) x d(-1) i.p. respectively for 5 days, and one normal saline control group. The DNA damage of spermatogenic cell by single-cell gel electrophoresis technology was detected. The expression positive rate of Bcl-2, Bax protein in spermatogenic cell by the immunohistochemical method was assayed, and the ultrastructural change of spermatogenic cell by the transmission electron microscope was observed.</p><p><b>RESULTS</b>DNA damage rates of of spermatogenic cell in 1, 5, 10 micromol/kg cadmium chloride groups were higher than that of normal group (P < 0.001). Bcl-2 protein expression positive rates were lower than that of normal group (P < 0.001). Bax protein positive expression rate in 5 micromol/kg group was higher than those in normal group, and 1, 10 micromol/kg groups. The ultrastructure of karyotis, karyotheca, mitochondria, endoplasmic reticulum in three treated groups had different degree of damage and the degree of ultrastructural change was increasing with rising concentration of cadmium.</p><p><b>CONCLUSION</b>Cadmium exposure will cause the DNA break, Bcl-2 and Bax protein abnormal expression and ultrastructural change in spermatogenic cell.</p>