RIPK4 Promotes Cell Invasion and the Epithelial-Mesenchymal Transition in Ovarian Cancer.

OBJECTIVE: To investigate the clinical role and biological function of receptor-interacting protein kinase 4 (RIPK4) in ovarian cancer (OC). METHODS: We conducted a comprehensive analysis of the expression and prognostic role of RIPK4 in OC using various public databases including The Cancer Genome Atlas, Oncomine, and Kaplan-Meier plotter. In vitro studies included wound healing, cell migration and invasion, cell proliferation, and cell apoptosis assays as well as vascular mimicry experiments. In vivo studies were conducted using subcutaneous and intraperitoneal xenografts. RESULTS: Our findings revealed that RIPK4 was significantly overexpressed in OC tissue compared to normal ovarian tissue. Moreover, the overexpression of RIPK4 was associated with advanced-stage disease and a poor prognosis in OC patients. RIPK4 silencing resulted in significant inhibition of intraperitoneal tumor growth, invasion, and vascular mimicry in OC cells. Furthermore, downregulation of RIPK4 inhibited the epithelial-mesenchymal transition of OC cells both in vitro and in vivo by promoting the expression of E-cadherin and inhibiting the expression of N-cadherin. CONCLUSION: The results of this study suggest that RIPK4 may function as an oncogene in the development and prognosis of OC.

Low oil emulsion gel stabilized by defatted Antarctic krill (Euphausia superba) protein using high-intensity ultrasound.

Emulsion gels with low oil contents have been continuously developed in recent decades. In this study, the use of high-intensity ultrasound for the preparation of low oil emulsion gel (oil fraction of 0.25) was investigated. Specifically, defatted Antarctic krill protein (dAKP) was used to stabilize the interface of soybean oil and water. Then, the microstructure and the stabilization mechanism of the formed emulsion gel were evaluated by cryo-SEM, CLSM, zeta potential, rheological measurements, and FTIR. Besides, the particle diameter was measured to be around 5 µm. The results of CLSM indicated that the emulsion gel was the oil-in-water type. The emulsion gel exhibited gel-like viscoelastic behavior even at a low concentration of dAKP due to the formation of a rigid particle network while the rheological behavior of the emulsion gel was significantly affected by the concentration of dAKP. The stabilization of the emulsion gel can be maintained by space steric hindrance and hydrophobic interactions between particles in the emulsion gel system.

Dispersive liquid-liquid microextraction for rapid and inexpensive determination of tetramethylpyrazine in vinegar.

The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid-liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L-1 and limit of quantification (LOQ) of 0.005 mg L-1. The developed method exhibited excellent linearity in the concentration range of 0.050-80.000 mg L-1, with a correlation coefficient R2 > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97-105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.

Effect of alkyl distribution in pyrazine on pyrazine flavor release in bovine serum albumin solution.

The flavor release mechanism related to the interaction of aroma compounds with proteins is still unclear. In this study, the interaction of protein with pyrazine homologues, such as 2-methylpyrazine (MP), 2,5-dimethylpyrazine (DP), 2,3,5-trimethylpyrazine (TRP) and 2,3,5,6-tetramethylpyrazine (TEP), was investigated to elucidate the effect of alkyl distribution in a pyrazine ring on its flavor release in bovine serum albumin (BSA) solution (pH 7.4). The results of SPME-GC-MS indicated that methyl distribution in a pyrazine ring significantly affected its release from BSA solution. The pyrazines released from BSA solution with an increasing order of MP, DP, TRP and TEP. The inhibition mechanism of alkyl-pyrazine release was further elucidated by the interaction between alkyl-pyrazines and BSA using multiple spectroscopic methods. The non-covalent interaction between alkyl-pyrazines and BSA was confirmed as the main interaction force by the value of the bimolecular quenching constant (K q > 2 × 1010 L mol-1 s-1). A decrease in the hydrophobicity of the microenvironment between the alkyl-pyrazine and BSA was detected by synchronous fluorescence spectra, which revealed that alkyl-pyrazines were mainly bound on the sites of tyrosine and tryptophan in BSA. The UV-vis absorption spectra and circular dichromatic (CD) spectrum revealed that alkyl-pyrazines could induce polarity and conformation change of BSA. The above results indicated that the structure of the flavor homologues can affect their release in food matrices.

Isotope dilution determination for the trace level of 4(5)-methylimidazole in beverages using dispersive liquid-liquid microextraction coupled with ESI-HPLC-MS/MS.

In this study, a rapid and reliable pretreatment method called dispersive liquid-liquid microextraction (DLLME) was developed for the determination of 4(5)-methylimidazole (4-MeI) in beverages. The clean-up samples were analyzed by a high performance liquid chromatography coupled with triple quadrupole mass spectrometer (HPLC-MS/MS) using a reversed-phase C18 column (250 mm × 4.6 mm, 5 µm). The matrix effects and the fault of DLLME operation were corrected by the isotope dilution technique. The developed method exhibited the limit of quantification (0.3 µg L-1) and excellent linearity (R2 = 0.999). In addition, the recovery values of 4-MeI in carbonated beverage were ranging from 102.60% to 113.22%, in soft drinks were ranging from 103.24% to 108.85%. The content 4-MeI was detected in thirteen beverage samples treated with DLLME and solid phase extraction method (SPE) (ranging from 6.4 to 165.5 µg L-1). The consistent result of 4-MeI content detected by DLLME and SPE method concluded that the established method on the basis of DLLME was rapid, robust and accurate for the trace 4-MeI determination in beverages.

Loss of stromal caveolin-1 expression in colorectal cancer predicts poor survival.

AIM: To investigate the clinicopathological significance and prognostic value of caveolin-1 (CAV-1) in both tumor and stromal cells in colorectal cancer (CRC). METHODS: A total of 178 patients with CRC were included in this study. The correlation between CAV-1 expression and clinicopathologic features and survival was studied. RESULTS: CAV-1 expression was detected in tumor and stromal cells. The expression of stromal CAV-1 was closely associated with histological type (P=0.022), pathologic tumor-node-metastasis stage (P=0.047), pathologic N stage (P=0.035) and recurrence (P=0.000). However, tumor cell CAV-1 did not show any correlation with clinical parameters. Additionally, the loss of stromal CAV-1 expression was associated with shorter disease-free survival (P=0.000) and overall survival (P=0.000). Multivariate analysis revealed that the loss of stromal CAV-1 expression was an independent prognostic factor for both overall survival (P=0.014) and disease-free survival (P=0.006). CONCLUSION: The loss of stromal CAV-1 expression in CRC was associated with poor prognosis and could be a prognostic factor for CRC patients.

Oxamate-mediated inhibition of lactate dehydrogenase induces protective autophagy in gastric cancer cells: involvement of the Akt-mTOR signaling pathway.

Cancer cells produce a substantial amount of energy through aerobic glycolysis even in the presence of adequate oxygen. Lactate dehydrogenase (LDH), a key regulator of glycolysis, reversibly catalyzes the conversion of pyruvate to lactate. Recently, oxamate, an inhibitor of LDH, has been shown to be a promising anticancer agent. However, the detailed mechanism remains largely unclear. In this study, we demonstrate that oxamate inhibits the viability of human gastric cancer cells in a dose- and time-dependent manner. In addition, treatment with oxamate induces protective autophagy in gastric cancer cells. Moreover, autophagy inhibited by chloroquine or Beclin 1 small interfering RNA (siRNA) enhances oxamate-induced apoptosis and proliferation inhibition. Further study has shown that oxamate treatment significantly augments reactive oxygen species (ROS) production. Furthermore, cells pretreated with N-acetyl cysteine (NAC), a ROS inhibitor, display significantly reduced ROS production and attenuated oxamate-induced autophagy. Finally, functional studies reveal that the Akt-mTOR signaling pathway, a major negative regulator of autophagy, is inhibited by oxamate. Together, our results provide new insights regarding the biological and anti-proliferative activities of oxamate against gastric cancer, and may offer a promising therapeutic strategy for gastric cancer.

The clinicopathologic importance of serum lactic dehydrogenase in patients with gastric cancer.

BACKGROUND: To explore possible correlation between serum lactate dehydrogenase (SLDH) levels and gastric cancer. MATERIALS AND METHODS: We retrospectively reviewed 365 patients with gastric cancer. The correlation of SLDH levels with clinicopathologic features and survival rate was studied. RESULTS: SLDH levels were closely associated with the pathological (p) T stage (P = 0.011), metastasis (P = 0.012), pTNM stage (P = 0.001), and recurrence (P = 0.012). Moreover, we found a significant SLDH level difference among Borrmann type (P = 0.027), pT stage (P = 0.004), lymph node metastasis (P = 0.027), metastasis (P < 0.001), pTNM stage (P = 0.006), and recurrence (P = 0.002). In addition, we detected a significant SLDH level difference between alive and dead subgroups (P = 0.001). In addition, both univariate analysis and multivariate analysis showed that high SLDH levels were independent prognostic factor. For the subgroup with normal LDH (median point of 157.0 U/L), we detected that the subset with SLDH levels ≥157 U/L (158-245 U/L) showed poorer OS (P = 0.005) and DFS (P = 0.01) than that of ≤157 subgroup. CONCLUSIONS: Our results suggest that high SLDH level could be an independent poor prognostic biomarker. Gastric cancer patients with relative high SLDH level (158-245 U/L) were prone to develop a shorter OS and DFS.

Transanal natural orifice specimen extraction for laparoscopic anterior resection in rectal cancer.

AIM: To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection. METHODS: A prospectively designed database of a consecutive series of patients undergoing laparoscopic low anterior resection for rectal cancer with various tumor-node-metastasis classifications from March 2011 to February 2012 at the First Affiliated Hospital of Sun Yat-Sen University was analyzed. Patient selection for transanal specimen extraction and intracorporeal anastomosis was made on the basis of tumor size and distance of rectal lesions from the anal verge. Demographic data, operative parameters, and postoperative outcomes were assessed. RESULTS: None of the patients was converted to laparotomy. Respectively, there were 16 cases in the low anastomosis and five in the ultralow anastomosis groups. Mean age of the patients was 45.4 years, and mean body mass index was 23.1 kg/m². Mean distance of the lower edge of the lesion from the anal verge was 8.3 cm. Mean operating time was 132 min, and mean intraoperative blood loss was 84 mL. According to the principle of rectal cancer surgery, we performed D2 lymph node dissection in 13 cases and D3 in eight. Mean lymph nodes harvest was 17.8, and the number of positive lymph nodes was 3.4. Median hospital stay was 6.7 d. No serious postoperative complication occurred except for one anastomotic leakage. All patients remained disease free. Mean Wexner score was 3.7 at 11 mo after the operation. CONCLUSION: Transanal NOSE for total laparoscopic low/ultralow anterior resection is feasible, safe and oncologically sound. Further studies with long-term outcomes are needed to explore its potential advantages.

[Low and ultralow anterior resection with hand-assisted laparoscopic surgery for rectal cancer].

OBJECTIVE: To summarize the experience and short-term clinical outcomes of hand-assisted laparoscopic surgery (HALS) in sphincter-preserving surgery for low and ultralow rectal cancer. METHODS: Data of 49 patients with rectal cancer who underwent HALS for low or ultralow anterior resection between January 2010 and January 2011 were analyzed retrospectively. RESULTS: The proximal resection margin was (14.3±6.9) cm and the distal margin was(4.3±1.9) cm. The mean operative time was(128.3±70.9) min. On postoperative macroscopic evaluation, the mesorectum was intact in 42 cases, nearly intact in 7 cases. The circumferential resection margin was more than 2 mm in 42 cases, and less than 2 mm in 7 cases. Forty-six patients underwent R0 resection, and 3 cases underwent R1 resection. The median retrieved lymph node (LN) was 16.20±9.23, and the median positive LN was 1.12±2.19. Postoperative pathological examination showed TNM stage was I( in 12 patients, II(A in 18, II(B in 1, III(A in 2, III(B in 8, III(C in 5, IIII( in 3. The median postoperative hospital stay was (6.25±3.87) d. There were no anastomotic leakage, ileus, intra-abdominal or anastomotic bleeding. There were two wound infections. CONCLUSION: Low and ultralow anterior resection for rectal cancer using HALS approach is safe and feasible with favorable short-term outcome.

A heat-activated calcium-permeable channel--Arabidopsis cyclic nucleotide-gated ion channel 6--is involved in heat shock responses.

An increased concentration of cytosolic calcium ions (Ca²âº) is an early response by plant cells to heat shock. However, the molecular mechanism underlying the heat-induced initial Ca²âº response in plants is unclear. In this study, we identified and characterized a heat-activated Ca²âº-permeable channel in the plasma membrane of Arabidopsis thaliana root protoplasts using reverse genetic analysis and the whole-cell patch-clamp technique. The results indicated that A. thaliana cyclic nucleotide-gated ion channel 6 (CNGC6) mediates heat-induced Ca²âº influx and facilitates expression of heat shock protein (HSP) genes and the acquisition of thermotolerance. GUS and GFP reporter assays showed that CNGC6 expression is ubiquitous in A. thaliana, and the protein is localized to the plasma membrane of cells. Furthermore, it was found that the level of cytosolic cAMP was increased by a mild heat shock, that CNGC6 was activated by cytosolic cAMP, and that exogenous cAMP promoted the expression of HSP genes. The results reveal the role of cAMP in transduction of heat shock signals in plants. The correlation of an increased level of cytosolic cAMP in a heat-shocked plant with activation of the Ca²âº channels and downstream expression of HSP genes sheds some light on how plants transduce a heat stimulus into a signal cascade that leads to a heat shock response.