The pluripotency of embryonic stem cells (ESCs) is maintained by intracellular networks of many pluripotency-associated (PA) proteins such as OCT4, SOX2, and NANOG. However, the mechanisms underlying the regulation of protein homeostasis for pluripotency remain elusive.Here, we first demonstrate that autophagy acts together with the ubiquitin-proteasome system (UPS) to modulate the levels of PA proteins in human ESCs (hESCs). Autophagy inhibition impaired the pluripotency despite increment of PA proteins in hESCs. Immunogold-electron microscopy confirmed localization of OCT4 molecules within autophagosomes. Also, knockdown of LC3 expression led to accumulation of PA proteins and reduction of pluripotency in hESCs. Interestingly, autophagy and the UPS showed differential kinetics in the degradation of PA proteins. Autophagy inhibition caused enhanced accumulation of both cytoplasmic and nuclear PA proteins, whereas the UPS inhibition led to preferentially degrade nuclear PA proteins. Our findings suggest that autophagy modulates homeostasis of PA proteins, providing a new insight in the regulation of pluripotency in hESCs. STEM CELLS 2014;32:424-435

BackgroundA family history can be a valuable tool in the era of precision medicine. Although a few studies have described an association of family history of lung cancer with EGFR activating mutation, their impact on survival of lung cancer patients is unclear.MethodsThe study included consecutive 829 non-small-cell lung cancer patients who received analysis of EGFR mutation in a prospective lung cancer cohort. Family history of lung cancer was obtained by face-to-face interviews at the time of diagnosis. An association of EGFR activating mutation with a family history of lung cancer in first-degree relatives was evaluated with multivariate logistic regression analysis, and its association with survival was estimated with Cox’s proportional hazards model.ResultsSeventy five (9.0%) patients had family history of lung cancer. The EGFR mutation was commonly observed in patients with positive family history compared to those with no family history (46.7% v 31.3%, χ2 p = 0.007). The family history was significantly associated with the EGFR mutation (aOR and 95% CI: 2.01 and 1.18–3.60, p = 0.011). Patients with the positive family history survived longer compared to those without (MST, 17.9 v 13.0 months, log-rank p = 0.037). The presence of the EGFR mutation was associated with better survival in patients without the family history (aHR and 95% CI: 0.72 and 0.57–0.90, p = 0.005). However, this prognostic impact was not observed in patients with the positive family history (aHR and 95% CI: 1.01 and 0.50–2.36, p = 0.832).ConclusionsIn comparison to patients without the family history, EGFR activating mutation was common, and it did not affect prognosis in patients with positive family history.

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