Deregulation of the receptor tyrosine kinase Axl has been implicated in the progression of several human cancers. However, the role of Axl in prostate cancer remains poorly understood, and the therapeutic efficacy of Axl targeting remains untested. In this report we identified Axl as a new therapeutic target for prostate cancer. Axl is consistently overexpressed in prostate cancer cell lines and human prostate tumors. Interestingly, the blockage of Axl gene expression strongly inhibits proliferation, migration, invasion, and tumor growth. Furthermore, inhibition of Axl expression by small interfering RNA regulates a transcriptional program of genes involved in cell survival, strikingly all connected to the NF-κB pathway. Additionally, blockage of Axl expression leads to inhibition of Akt, IKKα and IκBα phosphorylation, increasing IκBα expression and stability. Furthermore, induction of Akt phosphorylation by IGF1 in Axl knockdown cells restores Akt activity and proliferation. Taken together our results establish an unambiguous role for Axl in prostate cancer tumorigenesis with implications for prostate cancer treatment.

Axl expression is deregulated in several cancer types, predicts poor overall patient survival and is linked to resistance to drug therapy. Here, we evaluated a library of natural compounds for inhibitors of Axl and identified dihydroartemisinin, the active principle of the anti-malarial drug artemisinin, as an Axl-inhibitor in prostate cancer. Dihydroartemisinin blocks Axl expression leading to apoptosis, decrease in cell proliferation, migration, and tumor development of prostate cancer cells. Dihydroartemisinin treatment synergizes with docetaxel, a standard of care in metastatic prostate cancer increasing overall survival of mice with human xenografts. Dihydroartemisinin control of miR-34a and miR-7 expression leads to inhibition of Axl expression in a process at least partially dependent on regulation of chromatin via methylation of histone H3 lysine 27 residues by Jumonji, AT-rich interaction domain containing 2 (JARID2), and the enhancer of zeste homolog 2. Our discovery of a previously unidentified miR-34a/miR-7/JARID2 pathway controlling dihydroartemisinin effects on Axl expression and inhibition of cancer cell proliferation, migration, invasion, and tumor formation provides new molecular mechanistic insights into dihydroartemisinin anticancer effect on prostate cancer with potential therapeutic implications.

Deregulation of Axl in esophageal squamous cell carcinoma (OSCC) with potential therapeutic implications is described for the first time. This paper also sheds light on the understanding of how Axl regulates OSCC development in vitro and in vivo. Axl expression leads to an Akt-dependent regulation of glycogen synthase kinase 3β activity and the nucluear factor kappaB (NF-κB) pathway, affecting the epithelial–mesenchymal transition.

BackgroundHIV and TB programs have rapidly scaled-up over the past decade in Sub-Saharan Africa and uninterrupted supplies of those medicines are critical to their success. However, estimates of stock-outs are largely unknown. This survey aimed to estimate the extent of stock-outs of antiretroviral and TB medicines in public health facilities across South Africa, which has the world’s largest antiretroviral treatment (ART) program and a rising multidrug-resistant TB epidemic.MethodsWe conducted a cross-sectional telephonic survey (October—December 2015) of public health facilities. Facilities were asked about the prevalence of stock-outs on the day of the survey and in the preceding three months, their duration and impact.ResultsNationwide, of 3547 eligible health facilities, 79% (2804) could be reached telephonically. 88% (2463) participated and 4% (93) were excluded as they did not provide ART or TB treatment. Of the 2370 included facilities, 20% (485) reported a stock-out of at least 1 ARV and/or TB-related medicine on the day of contact and 36% (864) during the three months prior to contact, ranging from 74% (163/220) of health facilities in Mpumalanga to 12% (32/261) in the Western Cape province. These 864 facilities reported 1475 individual stock-outs, with one to fourteen different medicines out of stock per facility. Information on impact was provided in 98% (1449/1475) of stock-outs: 25% (366) resulted in a high impact outcome, where patients left the facility without medicine or were provided with an incomplete regimen. Of the 757 stock-outs that were resolved 70% (527) lasted longer than one month.InterpretationThere was a high prevalence of stock-outs nationwide. Large interprovincial differences in stock-out occurrence, duration, and impact suggest differences in provincial ability to prevent, mitigate and cope within the same framework. End-user monitoring of the supply chain by patients and civil society has the potential to increase transparency and complement public sector monitoring systems.