Trastuzumab prolongs survival in HER2 positive breast cancer patients. However, resistance remains a challenge. We have previously shown that ADAM17 plays a key role in maintaining HER2 phosphorylation during trastuzumab treatment. Beside ADAM17, ADAM10 is the other well characterized ADAM protease responsible for HER ligand shedding. Therefore, we studied the role of ADAM10 in relation to trastuzumab treatment and resistance in HER2 positive breast cancer. ADAM10 expression was assessed in HER2 positive breast cancer cell lines and xenograft mice treated with trastuzumab. Trastuzumab treatment increased ADAM10 levels in HER2 positive breast cancer cells (p≤0.001 in BT474; p≤0.01 in SKBR3) and in vivo (p≤0.0001) compared to control, correlating with a decrease in PKB phosphorylation. ADAM10 inhibition or knockdown enhanced trastuzumab response in naïve and trastuzumab resistant breast cancer cells. Trastuzumab monotherapy upregulated ADAM10 (p≤0.05); and higher pre-treatment ADAM10 levels correlated with decreased clinical response (p≤0.05) at day 21 in HER2 positive breast cancer patients undergoing a trastuzumab treatment window study. Higher ADAM10 levels correlated with poorer relapse-free survival (p≤0.01) in a cohort of HER2 positive breast cancer patients. Our studies implicate a role of ADAM10 in acquired resistance to trastuzumab and establish ADAM10 as a therapeutic target and a potential biomarker for HER2 positive breast cancer patients.

The HER (ErbB) receptor tyrosine kinase receptors are implicated in many cancers and several anti-HER treatments are now approved. In recent years, a new group of compounds that bind irreversibly to the adenosine triphosphate binding pocket of HER receptors have been developed. One of these compounds, neratinib, has passed preclinical phases and is currently undergoing various clinical trials. This manuscript reviews the preclinical as well as clinical data on neratinib. As a pan-HER inhibitor, this irreversible tyrosine kinase inhibitor binds and inhibits the tyrosine kinase activity of epidermal growth factor receptors, EGFR (or HER1), HER2 and HER4, which leads to reduced phosphorylation and activation of downstream signaling pathways. Neratinib has been shown to be effective against HER2-overexpressing or mutant tumors in vitro and in vivo. Neratinib is currently being investigated in various clinical trials in breast cancers and other solid tumors, including those with HER2 mutation. Earlier studies have already shown promising clinical activity for neratinib. However, more translational research is required to investigate biomarkers that could help to predict response and resistance for selection of appropriate patients for treatment with neratinib, either as monotherapy or in combination with other drug(s).

Hypoxia-inducible factor 1a is a key regulator of the hypoxia response in normal and cancer tissues. It is well recognized to regulate glycolysis and is a target for therapy. However, how tumor cells adapt to grow in the absence of HIF1a is poorly understood and an important concept to understand for developing targeted therapies is the flexibility of the metabolic response to hypoxia via alternative pathways. We analyzed pathways that allow cells to survive hypoxic stress in the absence of HIF1a, using the HCT116 colon cancer cell line with deleted HIF1a versus control. Spheroids were used to provide a 3D model of metabolic gradients. We conducted a metabolomic, transcriptomic, and proteomic analysis and integrated the results. These showed surprisingly that in three-dimensional growth, a key regulatory step of glycolysis is Aldolase A rather than phosphofructokinase. Furthermore, glucose uptake could be maintained in hypoxia through upregulation of GLUT14, not previously recognized in this role. Finally, there was a marked adaptation and change of phosphocreatine energy pathways, which made the cells susceptible to inhibition of creatine metabolism in hypoxic conditions. Overall, our studies show a complex adaptation to hypoxia that can bypass HIF1a, but it is targetable and it provides new insight into the key metabolic pathways involved in cancer growth.Implications: Under hypoxia and HIF1 blockade, cancer cells adapt their energy metabolism via upregulation of the GLUT14 glucose transporter and creatine metabolism providing new avenues for drug targeting. Analysis of the HCT116 hypoxic metabolic phenotype. A-C, Metabolomics-and proteomics-integrated circos-plots showing significantly regulated features only in KON versus WTN, WTH versus WTN, KOH versus KON, and KOH versus WTH (upper side circos-plots). Adjusted P < 0.05 ( Ã ) or P < 0.01 ( ÃÃ ) are indicated for the different experimental comparisons (connecting lines inside circos-plots): KON/WTN (gray/white-gray connection) WTH/WTN (gold/white-brown connection), KOH/KON (blue/gray-violet connection), KOH/WTH (blue/gold-green connection). Colored boxes (lower side circos-plots linked to connecting lines) represent different metabolic pathways, while colored boxes (inside circos-plots linked to connecting lines) identify the biological condition where the feature is upregulated. D, Heatmap of integrated transomics (proteomics and transcriptomics); mRNA and protein log 2 FC are calculated for WTH-WTN and KOH-WTH. Feature selection was based on departure from 95% confidence intervals of the linear model distribution built for each comparison (WTH-WTN and KOH-WTH). Metabolic pathways: glycogen (GLG), glycolysis (GLY), Krebs cycle (TCA), adenosine triphosphate (ATP), creatine (Cr), oxidation-reduction (REDOX), and adenosyl metabolism (ADE). E, Targeted metabolomics showing distribution of ATP, ADP, AMP, ATP/AMP, and ATP/ADP ratios in WTN, KON, WTH, and KOH cell after 24 hours in 21% and 1% O 2 . Raw intensities and ratios are shown as 0-1 normalized levels' rela...