Hypoxia signaling is an ancient pathway by which animals can respond to low oxygen. Malfunction of this pathway disturbs hypoxic acclimation and can result in various diseases, including cancers. The role of hypoxia signaling in early embryogenesis remains unclear. Here, we show that in the blastula of the sea urchin , hypoxia-inducible factor α (HIFα), the downstream transcription factor of the hypoxia pathway, is localized and transcriptionally active on the future dorsal side. This asymmetric distribution is attributable to its oxygen-sensing ability. Manipulations of the HIFα level entrained the dorsoventral axis, as the side with the higher level of HIFα tends to develop into the dorsal side. Gene expression analyses revealed that HIFα restricts the expression of to the ventral side and activates several genes encoding transcription factors on the dorsal side. We also observed that intrinsic hypoxic signals in the early embryos formed a gradient, which was disrupted under hypoxic conditions. Our results reveal an unprecedented role of the hypoxia pathway in animal development.

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Aims Despite being an essential therapy for breast cancer, trastuzumab has potential risks of cardiotoxicity. The incidence of trastuzumab-related major adverse cardiac and cerebrovascular event (MACCE) and its predictors remain unknown in Taiwan. Methods and results Through a three-hospital retrospective cohort study, we analyzed the incidence of MACCE in 386 breast cancer patients exposure to trastuzumab from 2010 to 2018. To further reconfirm our findings, in a nationwide study using the Taiwanese National Health Insurance Research Database and National Cancer Registry, we identified 13502 women diagnosed with breast cancer who received chemotherapy from 2010 to 2015 and found 6751 women who received initial treatment with trastuzumab. After 1:1 propensity score matching with trastuzumab nonusers, the incidence of MACCE was measured with a median follow-up of 36 months. In the hospital-based study, among 386 patients receiving trastuzumab, the 5-year incidences of MACCE and heart failure (HF) were 5.4% and 2.8%, respectively. In the national cohort, the crude incidences of MACCEs and HF were 4.67% and 3.21%, respectively. After adjustment for age and comorbidities, the hazard ratio of MACCE was 1.485 (95% CI 1.246–1.769). Notably, among the endpoints, only the hazard ratio of HF was significantly higher in patients receiving trastuzumab than in nonusers. In the subgroup analysis, except for patients also using taxanes, those receiving trastuzumab had a higher risk of MACCE than nonusers. Conclusions From clinical observations in a nationwide cohort, we found an increased risk of MACCE, especially HF, in patients receiving trastuzumab. Given that its cardiotoxicity is independent of traditional cardiovascular risks, our findings highlight critical concerns regarding the cardiac safety of trastuzumab use. FUNDunding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): Chi-Mei Medical Center, National Cheng Kung University Hospital