The Application of the RNA Interference Technologies for KRAS: Current Status, Future Perspective and Associated Challenges.

KRAS is a member of the murine sarcoma virus oncogene-RAS gene family. It plays an important role in the prevention, diagnosis and treatment of tumors during tumor cell growth and angiogenesis. KRAS is the most commonly mutated oncogene in human cancers, such as pancreatic cancers, colon cancers, and lung cancers. Detection of KRAS gene mutation is an important indicator for tracking the status of oncogenes, highlighting the developmental prognosis of various cancers, and the efficacy of radiotherapy and chemotherapy. However, the efficacy of different patients in clinical treatment is not the same. Since RNA interference (RNAi) technologies can specifically eliminate the expression of specific genes, these technologies have been widely used in the field of gene therapy for exploring gene function, infectious diseases and malignant tumors. RNAi refers to the phenomenon of highly specific degradation of homologous mRNA induced by double-stranded RNA (dsRNA), which is highly conserved during evolution. There are three classical RNAi technologies, including siRNA, shRNA and CRISPR-Cas9 system, and a novel synthetic lethal interaction that selectively targets KRAS mutant cancers. Therefore, the implementation of individualized targeted drug therapy has become the best choice for doctors and patients. Thus, this review focuses on the current status, future perspective and associated challenges in silencing of KRAS with RNAi technology.

miR-144 suppresses proliferation and induces apoptosis of osteosarcoma cells via direct regulation of mTOR expression.

Studied as a type of tumor suppressor, microRNA (miR) performs an important role in growth and apoptosis of various human carcinomas. However, the effects of miR-l44 on osteosarcoma growth and apoptosis, as well as possible underlying mechanisms, remain unclear. The present study investigated the expression of miR-144 in osteosarcoma MG-63 and U-2 OS cell lines compared with osteoblast cells. In order to elucidate the effects of miR-144 on osteosarcoma, miR-144 was upregulated in MG-63 and U-2 OS cells by transfecting chemically synthesized miR-144 mimics. Bioinformatics analysis of potential miR-144 target genes was performed using TargetScanHuman 7.0 and confirmed by luciferase assay. This analysis identified mammalian target of rapamycin (mTOR) as a target of miR-144. The present results indicated that the overexpression of miR-144 may significantly inhibit proliferation and promote apoptosis of MG-63 and U-2 cells compared with scramble control. Furthermore, the effects of miR-144 on osteosarcoma were associated with the mTOR signaling pathway via directly targeting the 3' untranslated region of mTOR mRNA, resulting in a decrease in the level of mTOR protein. In summary, miR-144 was demonstrated to act as a tumor suppressor, which inhibits proliferation and promotes apoptosis of osteosarcoma cell lines. In addition, this effect was mediated by direct targeting on mTOR following inhibition of the mTOR signaling pathway. The present study suggested that miR-144 may be a candidate for the gene therapy of osteosarcoma.

The calcium-sensing receptor participates in testicular damage in streptozotocin-induced diabetic rats.

Male infertility caused by testicular damage is one of the complications of diabetes mellitus. The calcium-sensing receptor (CaSR) is expressed in testicular tissues and plays a pivotal role in calcium homeostasis by activating cellular signaling pathways, but its role in testicular damage induced by diabetes remains unclear. A diabetic model was established by a single intraperitoneal injection of streptozotocin (STZ, 40 mg kg-1 ) in Wistar rats. Animals then received GdCl 3 (an agonist of CaSR, 8.67 mg kg-1 ), NPS-2390 (an antagonist of CaSR, 0.20 g kg-1 ), or a combination of both 2 months after STZ injection. Diabetic rats had significantly lower testes weights and serum levels of testosterone compared to healthy rats, indicating testicular damage and dysfunction in STZ-induced diabetic rats. Compared with healthy controls, the testicular tissues of diabetic rats overexpressed the CaSR protein and had higher levels of malondialdehyde (MDA), lower superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, and higher numbers of apoptotic germ cells. The testicular tissues from diabetic rats also expressed lower levels of Bcl-2 and higher levels of Bax and cleaved caspase-3 in addition to higher phosphorylation rates of c-Jun NH 2 -terminal protein kinase (JNK), p38, and extracellular signaling-regulated kinase (ERK) 1/2. The above parameters could be further increased or aggravated by the administration of GdCl 3 , but could be attenuated by injection of NPS-2390. In conclusion, the present results indicate that CaSR activation participates in diabetes-induced testicular damage, implying CaSR may be a potential target for protective strategies against diabetes-induced testicular damage and could help to prevent infertility in diabetic men.

Clinical observations on the treatment of prolapsing hemorrhoids with tissue selecting therapy.

AIM: To compare the effects and postoperative complications between tissue selecting therapy stapler (TST) and Milligan-Morgan hemorrhoidectomy (M-M). METHODS: Four hundred and eighty patients with severe prolapsing hemorrhoids, who were admitted to the Shenyang Coloproctology Hospital between 2009 and 2012, were randomly divided into observation (n=240) and control (n=240) groups. Hemorrhoidectomies were performed with TST in the observation group and with the M-M technique in the control group. The therapeutic effects, operation security, and postoperative complications in the two groups were compared. The immediate and long-term complications were assessed according to corresponding criteria. Pain was assessed on a visual analogue scale. The efficacy was assessed by specialized criteria. The follow-up was conducted one year after the operation. RESULTS: The total effective rates of the observation and control groups were 99.5% (217/218) and 98.6% (218/221) respectively; the difference was not statistically significant (P=0.322). Their were significant differences between observation and control groups in intraoperative blood loss (5.07±1.14 vs 2.45±0.57, P=0.000), pain (12 h after the surgery: 5.08±1.62 vs 7.19±2.01, P=0.000; at first dressing change: 2.64±0.87 vs 4.34±1.15, P=0.000; first defecation: 3.91±1.47 vs 5.63±1.98, P=0.001), urine retention (n=22 vs n=47, P=0.001), anal pendant expansion after the surgery (2.35±0.56 vs 5.16±1.42, P=0.000), operation time (18.3±5.6 min vs 29.5±8.2 min, P=0.000), and the length of hospital stay (5.3±0.6 d vs 11.4±1.8 d, P=0.000). Moreover TST showed significant reductions compared to M-M in the rates of long-term complications such as fecal incontinence (n=3 vs n=16, P=0.003), difficult bowel movement (n=1 vs n=9, P=0.011), intractable pain (n=2 vs n=12, P=0.007), and anal discharge (n=3 vs n=23, P=0.000). CONCLUSION: TST for severe prolapsing hemorrhoids is a satisfactory technique for more rapid recovery, lower complication rates, and higher operation security.

Salvage of amputated upper extremities with temporary ectopic implantation followed by replantation at a second stage.

Salvage of the complex amputation of extremities, such as combined with devastating segmental injuries, extensive soft tissue defect, and multiple important organ injuries, continues to be a challenge for plastic surgeons. Temporary ectopic implantation of the amputated part to a healthy recipient site allows the patient to recover from critical combined injuries, radical debridements, and soft tissue repair. In this article, the authors report two cases of temporary ectopic implantation of complexly amputated forearms, followed by successful replantation to their anatomic positions at a second stage. The contralateral upper extremity is an acceptable recipient site for temporary ectopic implantation. In secondary replantation, a cross-arm flap can be designed to carry the vascular pedicle from the ectopic implantation recipient to improve blood supply to the replanted part when the second blood supply is established. The authors validated that temporary ectopic implantation of amputated parts provides an alternative procedure for the salvage of amputated extremities under special circumstances.

[Temporary ectopic implantation of amputated foot].

OBJECTIVE: To investigate an effective technique of temporary ectopic implantation for amputated extremity under complex condition. METHODS: Two cases of amputated foot, which could not be implanted primarily, were treated with temporary ectopic implantation. The other leg of patient was chosen as recipient site. The posterotibial artery and saphenous vein were chosen as recipient vessels. When the general condition and the proximal condition of the amputated part were suitable, the ectopic implanted feet were transferred to their anatomic positions. RESULTS: All the feet survived after the replantation. The injured limbs recovered their normal length and sensation. The patients could walk after 4-6 months. CONCLUSION: Temporary ectopic implantation is an ideal technique for the salvage of amputated limb and organ under special condition. Severed foot and lower segment of the leg under complex condition were the best indication for the temporary ectopic implantation.