Understanding effects of angiogenesis inhibition on tumor metabolism will allow to design new strategies in order to overcome resistance to anti-angiogenic therapy and improve therapeutic outcome in patients.
The focus of our research is to investigate the biology of metabolic heterogeneity of tumors and how this heterogeneity modulates and is itself modulated by anti-angiogenic therapy. In this conceptual framework, we are also keen to investigate the possible impact on tumor angiogenesis of therapeutic strategies targeting glycolysis and their combination with anti-angiogenic therapy.
Albeit less studied compared with genetic heterogeneity, it is increasingly recognized that tumors are metabolically heterogeneous. In general, both inter-tumor and intra-tumor metabolic heterogeneity can be observed and the biological basis of this phenomenon remains largely unexplored. Enhanced glycolytic activity, one of the best known metabolic hallmarks of cancer, is an heterogeneous trait of tumors and is inter-connected with another hallmark of cancer, namely angiogenesis. Indeed, it has been shown that soluble factors released by highly glycolytic tumor cells, such as lactic acid, modulate the stromal microenvironment, contributing to promote angiogenesis. On the other hand, it has also been observed that endothelial cells preferentially use glycolysis as energy source, especially during angiogenesis. Therefore, in the presence of highly glycolytic tumor cells a metabolic competition with endothelial cells could occur, and glucose could become a limiting substrate for angiogenesis. This provisional balance between two seemingly opposing forces could be further perturbed by anti-angiogenic therapies, which hit the microvasculature and simultaneously increase tumor glycolysis. These mechanisms could underscore modulation of the therapeutic activity of anti-angiogenic drugs by a tumor metabolic trait.
Our team pioneered investigation of metabolic effects of anti-angiogenic drugs in solid tumors. We initially established that VEGF blockade is accompanied by dramatic reduction in glucose and ATP levels in the tumor microenvironment (Nardo G. et al. Cancer Res 2011) and this metabolic change activates the LKB1/AMPK pathway, a sensor of nutrients starvation in cells. We further hypothesized that alterations affecting this pathway could modulate therapeutic response to anti-VEGF drugs, and validated this hypothesis in CRC and lung cancer patients treated with chemotherapy plus bevacizumab (Zulato E. et al., BJC 2014 and Bonanno L. et al., CCR 2017). In parallel, we found that anti-VEGF therapy impacts on the metabolic profile of tumors and exacerbates the Warburg phenotype of tumors. Importantly, some of these metabolic changes are stable and are associated with resistance to bevacizumab (Curtarello M. et al. Cancer Res 2015). Additional metabolic changes occurring in tumors treated with angiogenesis inhibitors are currently under investigation in collaboration with other groups (Curtarello M. et al., Cells 2019).
Conclusions and perspectives
Results of our ongoing studies will provide a multi-level representation of the connections between the glycolytic phenotype of tumors and certain genetic or epigenetic profiles, highlight the therapeutic potential of glycolysis inhibitors in combination with anti-angiogenic drugs, investigate effects of tumor glycolysis on angiogenesis, and establish the possible predictive value of metabolic markers in patients treated with anti-angiogenic drugs.
Decoding genetic alterations of lung cancer and tracking their dynamic changes by liquid biopsy represents an unprecedented advance to detect early response to systemic therapy.
The focus of this Project is to investigate dynamic changes of the cancer genome through serial analysis of tumor and plasma samples from non-small cell lung cancer (NSCLC) patients.
Among common solid tumors, NSCLC is probably the best example of successful clinical application of targeted therapies. Accordingly, genetic screening for actionable mutations or alterations in genes such as EGFR, ALK, ROS1 is current practice, as detection of such mutations enables prescription of certain targeted drugs, belonging to the family of tyrosine kinase inhibitors (TKI). In face of an increasing demand of genetic characterization of the tumor sample, in most cases there is a limiting amount of tissue available for molecular analysis. This stimulated the development of new methods, such as next generation sequencing (NGS), which enable parallel profiling of many genes of potential clinical interest starting from a minimal amount of tumor DNA. Moreover, it has been shown that tumor-specific mutations can be found in circulating tumor DNA (ctDNA) obtained from plasma, which has stimulated the development of so called “liquid biopsy” methods to track cancer-associated mutations through blood samples. This latter development has been very successful in NSCLC and enables to monitor genetic changes of cancer during treatment by minimally invasive methods.
Our team pioneered at IOV investigation of innovative methods to detect somatic mutations in NSCLC samples, including both NGS, droplet digital PCR (ddPCR), and detection of LOH techniques (Boldrin E. et al., Int J Mol Sci 2019). In 2019, we routinely genotyped >200 plasma samples from NSCLC patients, being one of the leading laboratories for molecular diagnostics of lung cancer in the Veneto region. Results of our ongoing studies show the feasibility of using NGS to profile NSCLC samples and its potential to uncover mutations in actionable genes which would not be found by routine analysis. We aim to further improve application of upcoming cutting edge technologies to clinical samples with the long-term aim to increase the percentage of patients who can access to targeted therapy.
We have also started to use NGS and ddPCR technologies for quantitative measurements of the mutational load in plasma and monitor its dynamic variations during therapy. This study will investigate whether molecular variations detected in cfDNA can even precede radiologic or clinical responses. In this conceptual framework, we are also keen to investigate possible early biomarkers of resistance to targeted therapies.
Targeting NOTCH intra-cellular localization and signalling in cancer by HDAC6 inhibitors.
The focus of this Project is to investigate the role of NOTCH signaling in cancer cells, including both T cell acute lymphoblastic leukemia (T-ALL) and certain solid tumors. Pre-clinical models are exploited to investigate the therapeutic activity of novel targeted drugs with the final aim to improve therapeutic outcome of patients with NOTCH-addicted tumors.
The NOTCH pathway plays a crucial role in T-cell lineage specification and thymic development and its deregulated activation has been linked to T-ALL development as well as maintenance of key cancer features of certain solid tumors. Notably, about 50-60% of T-ALL samples show activating mutations in NOTCH1 gene and 15% of T-ALL cases present mutations or deletions in its ubiquitin ligase FBW7. The established role of NOTCH in solid and hematological malignancies suggests that this pathway could be targeted for therapeutic purposes in NOTCH-driven malignancies. Consolidated therapeutic approaches include the use of gamma secretase inhibitors (GSI) that block NOTCH processing, alternative molecules that affect NOTCH signaling and antibodies or decoy peptides to target specific NOTCH receptors or their ligands, hypothetically overcoming adverse effects due to the pan-Notch signaling inhibition associated with GSI. However, although the target has been long identifed, existing drugs have shown severe limitations in early clinical trials, including lack of efficacy and toxicity, which have so far precluded their further clinical development. There is therefore a medical need to develop new therapeutic approaches and test them in pre-clinical models to target NOTCH signaling in cancer.
In past years, our team pioneered in collaboration with the pediatric onco-hematology unit the set-up of patient-derived xenografts from T acute lymphoblastic leukemia (T-ALL). We utilized these well-characterized models to investigate the biological effects and the therapeutic activity of a NOTCH1 neutralizing antibody (Agnusdei V. et al., Leukemia 2014) and subsequently to dissect molecular mechanisms of resistance to NOTCH1-targeted therapy (Agnusdei V. et al., Haematologica 2019). We also observed that histone deacetylase 6 (HDAC6) controls Notch3 trafficking and degradation in T-cell acute lymphoblastic leukemia cells, uncovering that HDAC6 inhibitors can be used to counteract growth of NOTCH3-addicted tumors (Pinazza M. et al., Oncogene 2018).
We have patented our observation that HDAC6 inhibitors down-regulate NOTCH3 expression and activity in cancer cells and are planning to investigate the therapeutic activity of novel HDAC6 inhibitors in pre-clinical models of T-ALL as well as breast and ovarian cancer bearing NOTCH3 over-expression.