Silencing Rac1 and Prex1 Inhibit Epithelial-Mesenchymal Transition in Human Gastric Cancer Cells Induced by Transforming Growth Factor-ß1.

BACKGROUND/AIMS: Transforming growth factor-beta can influence tumor cells, causing epithelial-mesenchymal transition and enhancing their invasion and metastasis ability. Rac1 protein could be used as an independent tumor diagnostic marker and survival predictor. Prex1 is closely related to cell metastasis. In this study, the impact of silencing Rac1 and Prex1 on transforming growth factor-beta 1-induced epithelial-mesenchymal transition and apoptosis of human gastric cancer cells MGC-803 and MKN45 was investigated. MATERIALS AND METHODS: MGC-803 and MKN45 cells received recombinant transforming growth factor-beta 1 (rTGF-ß1) treatments at various concentrations. Cell Counting Kit-8 kit was used to determine cell viability. Rac1 and Prex1 interference vectors were transfected into the rTGF-ß1-treated MGC-803 and MKN45 cells. Cell apoptosis and migration were detected by flow cytometry and scratch test, respectively. Western blot was used to detect the epithelial-mesenchymal transition-related markers E-cadherin, N-cadherin, vimentin, and PDLIM2 expression levels. RESULTS: The rTGF-ß1 (10 ng/mL) could promote MGC-803 and MKN45 cell viability. Silencing Rac1 and Prex1 could increase E-cadherin and PDLIM2 expression, decrease N-cadherin and vimentin expression, inhibit cell viability and migration, and promote apoptosis in rTGF-ß1-treated MGC-803 and MKN45 cells. CONCLUSIONS: Silencing Rac1 and Prex1 could inhibit epithelial-mesenchymal transition, reduce cell viability and migration, and promote apoptosis in human gastric cancer cells.

Paclitaxel, oxaliplatin, 5-fluorouracil and leucovorin combination chemotherapy in patients with recurrent or metastatic gastric cancer.

PURPOSE: This study evaluated the efficacy and toxicity of combination chemotherapy with paclitaxel, oxaliplatin, 5-fluorouracil and leucovorin (POFL) in patients with recurrent or metastatic gastric cancer. METHODS: One hundred and thirty-eight patients with histologically confirmed recurrent or metastatic gastric adenocarcinoma were treated with the POFL regimen: paclitaxel at a dose of 135 mg/m2 as a 3-hour intravenous infusion on day 1, oxaliplatin 85 mg/m2 and leucovorin 400 mg/m2 as an intravenous infusion over 2 hours on day 1, followed by 5-fluorouracil 2,400 mg/m2 as an infusion over a 46-hour period on 3 consecutive days, in a 2-week cycle. RESULTS: Twelve patients could not be evaluated for response because of the absence of any measurable lesions or early discontinuation of therapy, so responses were assessed in 126 patients. The overall objective response rate was 56.3% (95% CI, 47.5%-64.9%). The median time to progression was 6.7 months (95% CI, 5.8-7.6 months), and the median overall survival was 12.6 months (95% CI, 11.3-13.9 months). The most common grade 3 and 4 toxicities were neutropenia (50.7%), peripheral neurotoxicity (16.7%) and alopecia (27.5%). CONCLUSIONS: Combination chemotherapy with POFL offers a new, active and safe approach to the treatment of recurrent or metastatic gastric cancer.

Experimental confirmation of potential swept source optical coherence tomography performance limitations.

Optical coherence tomography (OCT) has demonstrated considerable potential for a wide range of medical applications. Initial work was done in the time domain OCT (TD-OCT) approach, but recent interest has been generated with spectral domain OCT (SD-OCT) approaches. While SD-OCT offers higher data acquisition rates and no movable parts, we recently pointed out theoretical inferior aspects to its performance relative to TD-OCT. In this paper we focus on specific limitations of swept source OCT (SS-OCT), as this is the more versatile of the two SD-OCT embodiments. We present experimental evidence of reduced imaging penetration, increased low frequency noise, higher multiple scattering (which can be worsened still via aliasing), increased need to control the distance from the sample, and saturation of central bandwidth frequencies. We conclude that for scenarios where the dynamic range is relatively low (e.g., retina), the distance from the sample is relatively constant, or high acquisition rates are needed, SS-OCT has a role. However, when penetration remains important in the setting of a relatively high dynamic range, acquisition rates above video rate are not needed, or the distance to the tissue is not constant, TD-OCT may be the superior approach.

Ultrasound-enhanced optical coherence tomography: improved penetration and resolution.

Increasing penetration remains one of the most important issues in optical coherence tomography (OCT) research, which we achieved with a parallel ultrasound beam. In addition to qualitative improvements of tissue imaging, quantitative improvements in resolution of up to 28%+/-2% was noted. At lower frequencies and energies the improvement occurred primarily by altering the detection of multiply scattered light (photon-phonon interaction), which was substantially greater in solids than in liquids (even though the liquid had the higher scattering coefficient). In conclusion, the use of an ultrasound beam with OCT appears the most effective means to date for increasing imaging penetration.