Therapeutic success of VEGF-based anti-angiogenic tumor therapy is limited due to resistance. Thus, new strategies for anti-angiogenic cancer therapy based on novel targets are urgently required. Our previous in vitro work suggested that small molecule Cdk5 inhibitors affect angiogenic processes such as endothelial migration and proliferation. Moreover, we recently uncovered a substantial role of Cdk5 in the development of lymphatic vessels. Here we pin down the in vivo impact of endothelial Cdk5 inhibition in angiogenesis and elucidate the underlying mechanism in order to judge the potential of Cdk5 as a novel anti-angiogenic and anti-cancer target. By the use of endothelial-specific Cdk5 knockout mouse models and various endothelial and tumor cell based assays including human tumor xenograft models, we show that endothelial-specific knockdown of Cdk5 results in excessive but non-productive angiogenesis during development but also in tumors, which subsequently leads to inhibition of tumor growth. As Cdk5 inhibition disrupted Notch function by reducing the generation of the active Notch intracellular domain (NICD) and Cdk5 modulates Notch-dependent endothelial cell proliferation and sprouting, we propose that the Dll4/Notch driven angiogenic signaling hub is an important and promising mechanistic target of Cdk5. In fact, Cdk5 inhibition can sensitize tumors to conventional anti-angiogenic treatment as shown in tumor xenograft models. In summary our data set the stage for Cdk5 as a drugable target to inhibit Notch-driven angiogenesis condensing the view that Cdk5 is a promising target for cancer therapy.

We demonstrate that limited two-channel EEG monitoring can distinguish quiet sleep from active sleep and may be suitable for investigating the development of sleep in infants in the neonatal intensive care setting.

Epithelial-mesenchymal transition (EMT) induces tumor-initiating cells (TIC), which account for tumor recurrence, metastasis, and therapeutic resistance. Strategies to interfere with EMT are rare but urgently needed to improve cancer therapy. By using the myxobacterial natural compound Archazolid A as a tool, we elucidate the V-ATPase, a multimeric proton pump that regulates lysosomal acidification, as a crucial player in EMT and identify the inhibition of V-ATPase by Archazolid A as a promising strategy to block EMT. Genetic knockdown and pharmacologic inhibition of the V-ATPase by Archazolid A interfere with the EMT process and inhibit TIC generation, as shown by a reduced formation of mammospheres and decreased cell motility. As an underlying mechanism, V-ATPase inhibition by Archazolid A disturbs the turnover of E-cadherin: Archazolid abrogates E-cadherin loss during EMT by interfering with its internalization and recycling. Our study elucidates V-ATPase as essential player in EMT by regulating E-cadherin turnover. Archazolid A is suggested as a promising therapeutic agent to block EMT and the generation of TICs. .

<p>Supplementary Figure 1: Epithelial-mesenchymal transition in HMLE Twist1-ER cells; Supplementary Figure 3: Archazolid A does not induce apoptosis in HMLE Twist1-ER cells;Supplementary Figure 2: Archazolid A inhibits V-ATPase activity of HMLE Twist1-ER cells; Supplementary Figure 4: Archazolid A does not influence self-renewal markers Sox2 and OCT-4;Supplementary Figure 5: Archazolid A does not influence EMT markers at mRNA level; Supplementary Figure 6: Vesicle Tracking</p>

<p>Supplementary Figure 1: Epithelial-mesenchymal transition in HMLE Twist1-ER cells; Supplementary Figure 3: Archazolid A does not induce apoptosis in HMLE Twist1-ER cells;Supplementary Figure 2: Archazolid A inhibits V-ATPase activity of HMLE Twist1-ER cells; Supplementary Figure 4: Archazolid A does not influence self-renewal markers Sox2 and OCT-4;Supplementary Figure 5: Archazolid A does not influence EMT markers at mRNA level; Supplementary Figure 6: Vesicle Tracking</p>