Jung Bo Yang

High-mobility group box 1 (HMGB1) protein regulates tumor-associated cell migration through the interaction with BTB domain

High-mobility group box 1 (HMGB1) was shown to be strongly implicated in high incidences of metastasis and the poor clinical pathologic conditions found in various human tumors. In this study, we explored the possible mechanism of HMGB1 in tumor metastases in vitro, using a human carcinoma cell system. BTB, as a negative regulator of cell cycle progression, was identified as a HMGB1 interacting partner. The ectopic expression of HMGB1 activates cell growth by suppressing BTB-induced cell death, decreasing Bax and p53 expression, while enhancing Bcl-xL, Bcl-2, cyclin D1, and NF-κB expression. HMGB1 activates the FAK/PI3K/mTOR signaling cascade, and BTB prominently inhibits HMGB1-induced oncogenesis. The effect of HMGB1 on FAK/mTOR signaling was also confirmed through the silencing of HMGB1 expression. These insights provide evidence that HMGB1 enhances cell proliferation and suppresses apoptosis. Collectively, our results show an underlying mechanism for an HMGB1-associated promotion of carcinoma cells.

WIF1 can effectively co-regulate pro-apoptotic activity through the combination with DKK1

Wnt inhibitory factor-1 (WIF1) is a conserved lipid-binding protein that interrupts Wnt ligands by interacting with their Frizzled receptors. Thus, they may suppress the activation of the Wnt/β-catenin triggered signaling cascade. Recently, we found that WIF1 can effectively co-regulate pro-apoptotic activity through the combination with Dickkopf-1 (DKK1). The tumor suppressor p53 protein expression was remarkably increased in the WIF1- and DKK1-transfected cells, along with p21. In contrast, expressions of the anti-apoptotic proteins, c-Myc and Bcl-2, were noticeably reduced. In addition, WIF1 and/or DKK1 significantly activated the transcription of p21 and p53, whereas c-Myc and Bcl-2 activities were remarkably reduced. The tumor suppressor WIF1 was also found to be capable of suppressing tumor growth through the inhibition of tumor angiogenesis in the cellular biological/physiological condition through the targeting of the PI3K/Akt/mTOR signaling pathway, while also being recognized as a Wnt antagonist factor in the Wnt cascade. Consistently, WIF1 conspicuously decreased the VEGF-induced phosphorylation of the PI3K/Akt signaling cascade components, including PDK1, mTOR, TSC-2, GSK-3β, and the p70S6K protein. Collectively, our results indicate for the first time that the tumor suppressor WIF1 is involved in angiogenesis and supplies a possible molecular target for the treatment of distinct malignant cancers, as well as several other associated diseases.

The effect of various assisted hatching techniques on the mouse early embryo development

Objective In search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers. Methods Four- to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mares serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed. Results Following a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05). Conclusion Our results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.

The effect of artificial shrinkage and assisted hatching on the development of mouse blastocysts and cell number after vitrification

Objective The goal of this study was to ascertain optimal assisted hatching (AH) method in frozen embryo transfer. We compared the effect of depending on whether mechanical or laser-AH was performed before or after the vitrification of embryo development rate and blastocyst cell numbers. Methods In order to induce superovulation, pregnant mares serum gonadotropin followed by human chorionic gonadotropin were injected into 4- to 5-week-old female mice. 2-cell embryos were then collected by flushing out the oviducts. The Expanded blastocysts were recovered after the collected embryos were incubated for 48 hours, and were then subjected to artificial shrinkage (AS) and cross-mechanical AH (cMAH) or quarter-laser zona thinning-AH (qLZT-AH) were carried out using the expanded blastocysts before or after vitrification. After 48 hours of incubation, followed by vitrification and thawing (V-T), and blastocysts were fluorescence stained and observed. Results The rate of formation of hatched blastocysts after 24 and 72 hours of incubation was significantly higher in the AS/qLZT-AH/V-T group than in the other groups (p<0.05). The cell number of the inner cell mass was higher in AS/V-T/non-AH and AS/V-T/cMAH groups than those of others (p<0.05). In the control group, the number of trophectoderm and the total cell number were higher than in the AS-AH group (p<0.05). Conclusion The above results suggest that AS and AH in vitrification of expanded blastocysts lead to the more efficient formation of hatched blastocysts in mice.

Two-port access versus four-port access laparoscopic ovarian cystectomy

Objective This study was conducted to compare the surgical outcomes between two-port access and four-port access laparoscopic ovarian cystectomy. Methods Four hundred and eighty nine patients who had received two-port access laparoscopic ovarian cystectomy (n=175) and four-port access laparoscopic ovarian cystectomy (n=314) in Chungnam National University Hospital from January 2009 to August 2012 were analyzed retrospectively. The data were compared between the bilaterality of the cysts and cyst diameter of less than 6 cm and 6 cm or more. Results There were no significant differences in patients age, parity, body weight, body mass index and history of previous surgery between the two-port and four-port access laparoscopy group. Bilaterality of ovarian cysts was more in fourport access laparoscopy group (13.7% vs. 32.5%, P=0.000). There were no significant differences in operation time, hemoglobin change, hospital stay, adhesiolysis, transfusion, and insertion of hemo-vac between the two-port and four-port access laparoscopy group for size matched compare. However additional analgesics were more in four-port access laparoscopy group for unilateral ovarian cystectomy. Conclusion Two-port access laparoscopic surgery was feasible and safe for unilateral and bilateral ovarian cystectomy compare with four-port access laparoscopic surgery.

Expression of Yes-associated protein 1 and its clinical significance in ovarian serous cystadenocarcinoma

Yes-associated protein 1 (YAP1) is a key transcriptional regulator in the Hippo signaling pathway that plays a critical role in the development and progression of several types of malignancies, including ovarian cancer. Herein, we investigated the expression of YAP1 and its clinical significance in a large population of patients with ovarian serous cystadenocarcinoma (OSC), which is the most common form of epithelial ovarian neoplasm, using the TCGA database. Surprisingly, cross-cancer mRNA expression and alterations in YAP1 were higher in OSC than in those of other types of cancers in the TCGA database. YAP1 mRNA expression was significantly higher in OSC compared with normal ovarian samples, and was higher in stages III and IV, than stages I and II. The level of YAP1 protein, which is mainly localized to the nucleus, was also higher in stage IV as compared with stages I, II and III. However, the protein level of pYAP1, which is inactive and is localized to the cytoplasm, was not significantly different between stages. The ratio of pYAP/YAP, which shows higher activity at a low ratio, was lower in stage III than in stages I and II. High YAP and low pYAP levels were significantly correlated with a poor prognosis in patients with OSC. The mRNA and protein expression of YAP1 were significantly increased in the proliferative subtype as compared to the differentiated, immunoreactive and mesenchymal subtypes. According to bioinformatics analysis, YAP1 is most highly correlated with the cell cycle. TGF-β signaling and WNT signaling were significantly increased in the high YAP1 group according to gene set enrichment analysis. Taken together, our results suggest that not only high YAP1 expression but also its subcellular distribution may be associated with poor overall survival in patients with OSC.

Effects of laser-assisted hatching and exposure time to vitrification solution on mouse embryo development

Objective This study was conducted to investigate the efficacy of laser-assisted hatching (LAH) and various vitrification times for embryonic development and blastocyst cell numbers. Methods First, 2-cell and 8-cell embryos were collected by flushing out the oviducts. In the control groups, they were vitrified for 8 or 10 minutes without LAH. The LAH groups underwent quarter laser zona thinning-assisted hatching before vitrification (4, 6, and 8 minutes or 4, 7, and 10 minutes, respectively). After incubation, double-immunofluorescence staining was performed. Results The hatched blastocyst rate 72 hours after the 2-cell embryos were thawed was significantly higher in the 2LAH-ES8 group (33.3%) than in the other groups (p<0.05). In the control-8 group (22.1±4.6), the cell number of the inner cell mass was higher than in the LAH groups (p<0.05). The number of trophectoderm cells was higher in the 2LAH-ES6 group (92.8±8.9) than in the others (p<0.05). The hatched blastocyst rate 48 hours after the 8-cell embryos were thawed was higher in the 8LAH-ES4 group (45.5%) than in the other groups, but not significantly. The inner cell mass cell number was highest in the 8LAH-ES7 group (19.5±5.1, p<0.05). The number of trophectoderm cells was higher in the 8LAH-ES10 group (73.2±12.1) than in the other groups, but without statistical significance. Conclusion When LAH was performed, 2-cell embryos with large blastomeres had a lower hatched blastocyst rate when the exposure to vitrification solution was shorter. Conversely, 8-cell embryos with small blastomere had a higher hatched blastocyst rate when the exposure to vitrification solution was shorter.

Lower limb compartment syndrome by reperfusion injury after treatment of arterial thrombosis post-laparoscopic radical hysterectomy and pelvic lymph node dissection for cervical cancer

Compartment syndrome is a clinical condition associated with decreased blood circulation that can lead to swelling of tissue in limited space. Several factors including lithotomy position, prolonged surgery, intermittent pneumatic compressor, and reperfusion after treatment of arterial thrombosis may contribute to compartment syndrome. However, compartment syndrome rarely occurs after gynecologic surgery. In this case, the patient was diagnosed as compartment syndrome due to reperfusion injury after treatment of arterial thrombosis, which occurred after laparoscopic radical hysterectomy and pelvic lymph node dissection for cervical cancer. Despite its rarity, prevention and identifying the risk factors of complication should be performed perioperatively; furthermore, gynecologist should be aware of the possibility of complications.

Comparing two different techniques of rectus sheath block after single port laparoscopic surgery in benign adnexal mass patients: Surgical versus ultrasonography guidance—A randomized, single-blind, case-controlled study

OBJECTIVE The purpose of this study was to compare the analgesic effect of surgical bilateral rectus sheath block (BRSB) and ultrasonography-guidance BRSB in patients undergoing single port laparoscopic surgery (SPLS) for ovarian cyst. STUDY DESIGN Seventy-five patients were randomly allocated into three groups: the control and ultrasound (US)-guidance group (n=25, each) received BRSB with 10ml of normal saline or 0.5% ropivacaine bilaterally under US guidance at the end of surgery, respectively; the surgical group (n=25) received BRSB with10ml of 0.5% ropivacaine bilaterally just before suturing the surgical site. All patients received intravenous fentanyl 50μg for postoperative pain before emergence from anesthesia. Additional self-administered fentanyl and pain intensity were measured at postoperative 1, 6, 10 and 24h. RESULTS Demographic characteristics showed no significant group-wise differences. The cumulative amount of fentanyl delivered was significantly lower in the US-guidance and surgical BRSB groups (189.20μg and 187.68μg, respectively) than the control group (286.40μg) on postoperative day 1 (P<0.001). At 24h, the median pain score was significantly lower only in the surgical BRSB group. In addition, opioid-related side effects were decreased in patients who received BRSB (control group 36% vs. US-guidance BRSB group 24% vs. surgical BRSB group 12%). CONCLUSIONS Both US-guided and surgical BRSB were effective for pain control in patients undergoing SPLS. Thus, surgical BRSB can be performed by gynecologists intra-operatively, for post-operative pain management.