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Abstract Background Human olfactomedin 4 (OLFM4) gene is a secreted glycoprotein more commonly known as the anti-apoptotic molecule GW112. OLFM4 is found to be frequently up-regulated in many types of human tumors including gastric cancer and it was believed to play significant role in the progression of gastric cancer. Although the function of OLFM4 has been indicated in many studies, recent evidence strongly suggests a cell or tissue type-dependent role of OLFM4 in cell growth and apoptosis. The aim of this study is to examine the role of gastric cancer-specific expression of OLFM4 in cell growth and apoptosis resistance. Methods OLFM4 expression was eliminated by RNA interference in SGC-7901 and MKN45 cells. Cell proliferation, anchorage-independent growth, cell cycle and apoptosis were characterized in vitro. Tumorigenicity was analyzed in vivo. The apoptosis and caspase-3 activation in response to hydrogen peroxide (H2O2) or tumor necrosis factor-alpha (TNF α) were assessed in the presence or absence of caspase inhibitor Z-VAD-fmk. Results The elimination of OLFM4 protein by RNA interference in SGC-7901 and MKN45 cells significantly inhibits tumorigenicity both in vitro and in vivo by induction of cell G1 arrest (all P < 0.01). OLFM4 knockdown did not trigger obvious cell apoptosis but increased H2O2 or TNF α-induced apoptosis and caspase-3 activity (all P < 0.01). Treatment of Z-VAD-fmk attenuated caspase-3 activity and significantly reversed the H2O2 or TNF α-induced apoptosis in OLFM4 knockdown cells (all P < 0.01). Conclusion Our study suggests that depletion of OLFM4 significantly inhibits tumorigenicity of the gastric cancer SGC-7901 and MKN45 cells. Blocking OLFM4 expression can sensitize gastric cancer cells to H2O2 or TNF α treatment by increasing caspase-3 dependent apoptosis. A combination strategy based on OLFM4 inhibition and anticancer drugs treatment may provide therapeutic potential in gastric cancer intervention.

Introduction: Lennox-Gastaut syndrome (LGS) is a severe subtype of childhood-onset epileptic encephalopathy with drug-resistant and poor surgical prognosis. However, electroencephalogram (EEG) patterns of symptomatic LGS or LG phenotypes with structural brain lesions including focal abnormalities or asymmetric slow-spike-wave (SSW) patterns remain largely unknown. Due to the contradictory lateralization difference between MRI lesions and EEG pattern in symptomatic LGS or LG phenotypes, it is difficult to determine the precise lateralization of epileptic lesions, which is crucial to better surgical prognosis. This study is aim to ascertain the clinical characteristics of the EEG patterns, and its relationship with MRI lesions and to evaluate its prognostic value of surgical treatment in symptomatic LGS or LG phenotypes. Methods: Twenty-four symptomatic LGS cases with asymmetric EEG SSW patterns and contralaterally independent or contralaterally dominant MRI lesions were collected, and their clinical features were analyzed retrospectively. Results: In this cohort, most of lesions were perinatal or acquired during the first 6 months of life. The most common etiology was intracerebral hemorrhage. The LGS patients with both asymmetric SSW and focal sporadic epileptic waves (SEW) patterns showed the best surgical outcome with Engel class I level. Asymmetric SSW patterns with maximal discharges contralateral to MRI lesions were frequently observed in most of symptomatic LGS or LG phenotypes. Predominantly diffuse destructive lesions led to an attenuated voltage of ipsilateral scalp EEG producing an asymmetric SSW pattern in those patients with symptomatic LGS or LG phenotypes. Conclusions: Our study reveals a special SEW EEG pattern in symptomatic LG patients with asymmetric SSW and MRI lesions contralateral to the dominant EEG patterns. Contradictory lateralization difference between MRI and EEG probably arises from the relative voltage attenuation presenting in EEG ipsilateral to huge destructive lesions from early life. Our study suggests that the independent focal SEW activity remaining ipsilateral to the MRI lesion can potentially predict better surgical prognosis in symptomatic LGS or LG phenotypes. [ABSTRACT FROM AUTHOR]