Circ-0104631 promotes cell proliferation and invasion in colorectal cancer and predicts poor prognosis.

OBJECTIVE: The aim of this study was to elucidate the effect of Circ-0104631 on the progression of colorectal cancer (CRC) and to demonstrate the underlying mechanism. Our research might provide new biological markers and molecular therapeutic targets for the diagnosis and therapy of CRC. PATIENTS AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect Circ-0104631 expression in human colorectal cancer tissues and normal control tissues. To further explore the effect of Circ-0104631 on CRC in vitro, we first knocked down Circ-0104631 in colorectal cancer cells (SW480 and LoVo) by shRNA transfection. Subsequently, we detected its effect on cell proliferation and invasion by cell counting kit-8 (CCK-8) assay, colony formation assay and cell invasion assay, respectively. The regulation of Circ-0104631 on the expressions of phosphate and tension homology deleted on chromosome ten (PTEN)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway-related proteins was detected by Western blot. Besides, the regulatory mechanism of Circ-0104631 on the progression and metastasis of CRC was further verified by recovery experiments. RESULTS: QRT-PCR results showed that Circ-0104631 was highly expressed in tissues of patients with CRC when compared with that of normal control tissues. At the same time, we also found that the expression of Circ-010463 was significantly up-regulated in CRC tissues with high topography lymph node metastasis (TNM) stage and distant metastasis. Survival curve analysis indicated that high expression of Circ-010463 predicted poor prognosis of CRC patients. In vitro experiment demonstrated that inhibition of Circ-0104631 in SW480 and LoVo cells could markedly decrease cell growth and metastasis abilities. Meanwhile, Western blot results indicated that the protein expression of PTEN increased significantly, while p-Akt and p-mTOR decreased remarkably after knock-down of Circ-0104631 in CRC cells. Furthermore, recovery experiments illustrated that knockdown of PTEN in SW480 and LoVo cells partially attenuated the inhibitory effect of shRNA-Circ-0104631 on cell growth and metastasis. CONCLUSIONS: Circ-0104631 was highly expressed in CRC tissues. Furthermore, knockdown of Circ-0104631 could inhibit the growth and metastasis of CRC cells by regulating PTEN/Akt/mTOR signaling pathway.

Co-culture of annulus fibrosus cells and bone marrow mesenchymal stem cells.

To investigate the effect on cell proliferation and extracellular matrix expression of annulus fibrosus (AF) cells when co-cultured with bone marrow mesenchymal stem cells (BMSCs). Primary isolated rabbit BMSCs and AF cells were cultured and harvested cells were placed into a 15-mL centrifugal tube co-culture system in a ratio of 2:1 (A group), 1:1 (B group), and 1:2 (C group). Cell proliferation was evaluated using cell counting kit-8, and mRNA of collagen II and mucopolysaccharide was quantified using real-time polymerase chain reaction (PCR) on Days 7, 14, and 21. The cell count, synthesized collagen II and mucopolysaccharide increased in a time-dependent manner, with a peak at Day 21. Cells in Group B proliferated faster and synthesized more collagen II and mucopolysaccharide than groups A and C, where the difference was significant. AF cells and BMSCs in the ratio of 1:1, cultured using the centrifugal tube three-dimensional co-culture system showed that BMSCs can promote AF cell proliferation and extracellular matrix synthesis.

Cloning of hypoxia-inducible factor 1alpha cDNA from a high hypoxia tolerant mammal-plateau pika (Ochotona curzoniae).

Hypoxia-inducible factor 1 is a transcription factor composed of HIF-1alpha and HIF-1beta. It plays an important role in the signal transduction of cell response to hypoxia. Plateau pika (Ochotona curzoniae) is a high hypoxia-tolerant and cold adaptation species living only at 3000-5000 m above sea level on the Qinghai-Tibet Plateau. In this study, HIF-1alpha cDNA of plateau pika was cloned and its expression in various tissues was studied. The results indicated that plateau pika HIF-1alpha cDNA was highly identical to those of the human (82%), bovine (89%), mouse (82%), and Norway rat (77%). The deduced amino acid sequence (822bp) showed 90%, 92%, 86%, and 86% identities with those of the human, bovine, house mouse, and Norway rat, respectively. Northern blot analyses detected two isoforms named pLHIF-1alpha and pSHIF-1alpha. The HIF-1alpha mRNA was highly expressed in the brain and kidney, and much less in the heart, lung, liver, muscle, and spleen, which was quite different from the expression pattern of mouse mRNA. Meanwhile, a new variant of plateau pika HIF-1alpha mRNA was identified by RT-PCR and characterized. The deduced protein, composed of 536 amino acids, lacks a part of the oxygen-dependent degradation domain (ODD), both transactivation domains (TADs), and the nuclear localization signal motif (NLS). Our results suggest that HIF-1alpha may play an important role in the pika's adaptation to hypoxia, especially in brain and kidney, and pika HIF-1alpha function pattern may be different from that of mouse HIF-1alpha. Furthermore, for the high ratio of HIF-1alpha homology among the animals, the HIF-1alpha gene may be a good phylogenetic performer in recovering the true phylogenetic relationships among taxa.