Selenocysteine inhibits human osteosarcoma cells growth through triggering mitochondrial dysfunction and ROS-mediated p53 phosphorylation.

Osteosarcoma represents the most common primary malignant bone tumor in children and adolescents, which shows severe resistance toward standard chemotherapy because of high invasive capacity and growing incidence. Selenocysteine (SeC) is a naturally available Se-containing amino acid that displays splendid anticancer activities against several human tumors. However, little information about SeC-induced growth inhibition against human osteosarcoma is available. Herein, the anticancer efficiency and underlying mechanism of SeC against human osteosarcoma were evaluated in vitro and in vivo. The results revealed that SeC significantly inhibited MG-63 human osteosarcoma cells growth in vitro through induction of S-phase arrest and apoptosis, as reflected by the decrease of cyclin A and CDK-2, PARP cleavage, and caspases activation. SeC treatment also resulted in mitochondrial dysfunction through affecting Bcl-2 family expression. Moreover, SeC triggered p53 phosphorylation by inducing reactive oxygen species (ROS) overproduction. ROS inhibition effectively blocked SeC-induced cytotoxicity and p53 phosphorylation. Importantly, MG-63 human osteosarcoma xenograft growth in nude mice was significantly suppressed in vivo through triggering apoptosis and p53 phosphorylation. These results indicated that SeC had the potential to inhibit human osteosarcoma cells growth in vitro and in vivo through triggering mitochondrial dysfunction and ROS-mediated p53 phosphorylation, which validated the potential application of Se-containing compounds in treatment of human osteosarcoma.

Effects of the Long Non-Coding RNA HOST2 On the Proliferation, Migration, Invasion and Apoptosis of Human Osteosarcoma Cells.

BACKGROUND/AIMS: This study aimed to explore the effects of the long non-coding RNA HOST2 (lnc-HOST2) on the proliferation, migration, invasion and apoptosis of osteosarcoma cells. METHODS: Osteosarcoma tissues and adjacent normal tissues from 52 patients were selected. Human osteosarcoma cell lines (SaOS2, HOS, U2OS and MG-63) were collected and cultured; MG-63 cells had the highest lnc-HOST2 expression and thus were used in subsequent experiments. Then, MG-63 cells were transfected and divided into the blank (no transfection), si-CON (transfected with negative control siRNA) and si-lnc-HOST2 (transfected with small interference lnc-HOST2 siRNA) groups. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of lnc-HOST2 in primary tissues and cells. Cell growth was detected using the CCK-8 and colony formation assays. Cell doubling time was detected. Cell migration and invasion were observed using the scratch test and Transwell assays. Cell apoptosis and cell cycle progression of osteosarcoma cells were detected using flow cytometry with annexin V/PI double staining and PI staining, respectively. RESULTS: The level of lnc-HOST2 expression in the si-lnc-HOST2 group was significantly decreased compared to that in the blank and si-CON groups. The OD values in the si-lnc-HOST2 group were significantly lower than those in the blank and si-CON groups. Compared to the blank and si-CON groups, the si-lnc-HOST2 group presented significant decreases in the colony number and healing rates after scratching. The number of invasive cells in the si-lnc-HOST2 group was significantly less than that in the blank and si-CON groups. In the si-lnc-HOST2 group, the cell cycle was mainly halted in the G1 phase, and the apoptosis rate and doubling time in this group were significantly higher than those in the blank group and si-CON group. CONCLUSIONS: Inhibition of lnc-HOST2 could suppress the proliferation, migration, and invasion and promote the apoptosis of osteosarcoma cells.

MicroRNA-150 Inhibits Cell Invasion and Migration and Is Downregulated in Human Osteosarcoma.

miR-150 expression in osteosarcoma (OS) cell lines and human osteoblast cells was detected, and OS cell models were transfected with exogenous miR-150 to investigate its role in cell proliferation, invasion, and apoptosis. Our results showed that miR-150 expression in OS cells (MG63, Saos-2, SOSP-9607, and U2OS) was significantly lower compared to the osteoblast hFOB1.19 cell line (all p < 0.01). The expression level of miR-150 in MG63 cells that were transfected with exogenous miR-150 mimics was markedly upregulated, while the miR-150 expression level in the inhibitor group was significantly downregulated (both p < 0.01). Similar results were also found in SOSP-9607 cells. Importantly, exogenous miR-150 expression stimulated cell apoptosis and inhibited proliferation, invasion, and migration. A luciferase reporter assay displayed that miR-150 also regulated Sp1 expression by targeting its 3'-UTR, and qRT-PCR and Western blotting showed that elevated levels of miR-150 may reduce Sp1 protein expression. The mRNA and protein levels of Sp1 were upregulated after transfection with a Sp1-expression plasmid and partially reversed the inhibitory effects of miR-150 on cell proliferation, invasion, and metastasis in MG63 and SOSP-9607 cells, as well as promoted cell apoptosis. In conclusion, miR-150 inhibits cell proliferation, invasion, and metastasis and stimulates cell apoptosis by regulating the expression of Sp1. Therefore, miR-150 may be a potential clinical target for the treatment of OS patients.

[Indications, technique and efficacy of organ preserving pancreatectomy].

OBJECTIVE: To discuss the proper surgical management of pancreatic benign and low-grade malignant potential neoplasm. METHODS: The experience of 72 cases who accepted organ preserving pancreatectomy from January 1990 to May 2010 was analyzed retrospectively. There were 24 male and 48 female, aged from 15 to 68 years with mean age of 46 years. There were 9 cases underwent duodenum-preserving resection of the head of the pancreas, 29 cases underwent spleen-preserving distal pancreatectomy, 11 cases underwent middle segmental pancreatectomy, 23 cases underwent tumor extirpation of huge pancreatic cancer in pancreatic head and body. RESULTS: Pancreatic fistula and biliary fistula in 1 case respectively were cured among who accepted duodenum-preserving resection of the head of the pancreas. Pancreatic fistula was found in 3 cases who accepted spleen-preserving distal pancreatectomy. Pancreaticobiliary anastomotic bleeding in 1 case was cured among who accepted middle segmental pancreatectomy. Pancreatic fistula was found in 5 cases among who accepted tumor extirpation of huge pancreatic cancer in pancreatic head and body, and liver metastasis was found in 3 cases at 6, 12, 16 months after surgery respectively. CONCLUSIONS: Organ preserving pancreatectomy can obviously reduce operative injury to patients, its therapeutic effect is similar to that of classical operation, it is the first option of benign and low-grade malignant potential neoplasm.

Experimental Study and Preliminary Clinical Application of Mini-invasive Percutaneous Internal Screw Fixation for Scaphoid Fracture under the Guidance of a 3D-printed Guide Plate.

This study explored the feasibility of employing computer-aided design (CAD) and 3 dimensional (3D)-printed personalized guide plate for the mini-invasive percutaneous internal screw fixation of fractured scaphoid. The study consisted of two parts: (1) experimentation on upper limbs from corpses and (2) preliminary clinical application. Corpse experiments involved upper limbs of 6 adult corpses. The specimens of upper limbs were subjected to plain CT scan. Then the CT data were input into computer to conduct 3D reconstruction of wrist region. The direction and depth of the guide wire and screw were designed on the basis of the principle that screw should lie at the center of scaphoid and the long axis of the screw should be aligned with that of the scaphoid. The carpal bone model and the guide plate were designed and 3D-printed. By using the guide plates, the guide wire was placed and the cannulated compression screw was inserted. The wrist region was examined by X-ray and CT to observe the location of the screw in the scaphoid. The scaphoid was longitudinally excised to grossly observe the location and evaluate the result of screw insertion. For clinical application, the guide plate was employed in 4 patients with fresh scaphoid fracture using the aforementioned operative technique. Our results showed that, in the 6 corpse limbs, the guide plate well fitted the skin surface and the guide wire and screw were accurately put in place in one session. X-ray examination and gross observation confirmed that the screw was satisfactorily positioned and the result met the requirements of the preoperative design. For 4 patients, the guide wire and screw were all precisely inserted into place in one session. The operation time and X-ray exposure times were apparently reduced. The imaging examination exhibited satisfactory results and the hand functioned well. It was concluded that the operative guide plate used for the mini-invasive percutaneous internal screw fixation of fractured scaphoid not only can assist in accurate placement of screw but also shorten operation time and reduce insertion and X-ray exposure times, thereby reducing the radiation injury and damage to the substance and the blood circulation of carpal bone. Its use can also improve the learning curve of surgeons.

Transglutaminase-2 is Involved in Cell Apoptosis of Osteosarcoma Cell Line U2OS Under Hypoxia Condition.

Osteosarcoma is the most common type of solid bone cancer, which is the second leading cause of cancer-related death. Hypoxia is an ordinary phenomenon in solid tumor tissues and can induce cell apoptosis but the specific molecular mechanism remains unclear. In this study, we explored the effect and the molecular mechanism of Transglutaminase 2 (TG2) on cell apoptosis in osteosarcoma U2OS cells under hypoxia. We found the enzymatic activity of TG2 is significantly increased and the expression of TG2 is remarkably up-regulated under hypoxia condition. Cell apoptotic rate is markedly increased upon knockdown of TG2 by siRNA under hypoxia. We further investigated the mechanism of cell apoptosis and found Bax protein is significantly increased after depletion of TG2 under hypoxia. Moreover, our data also show that cytochrome C (Cyt C) is significantly increased in cytoplasm and markedly decreased in mitochondria of U2OS cells after depletion of TG2 under hypoxia. Our results suggest that TG2 can inhibit tumor cell apoptosis through down-regulation of Bax and prevention of release Cyt C from mitochondria into cytoplasm.