Advocure honors Dr. Marco Giovannini, director of House Research Institute’s Center for Neural Tumor Research for his work on NF2.

From left to right: Jane Tran Ly, Sheila Heal, Dr. Marco Giovannini, Roland Thoms, Nicolas Xavier Bonne, Jérémie Vitte.

In January 2008, Dr. Giovannini founded the Center for Neural Tumor Research with a mission to translate research on the cellular and molecular basis of neurofibromatosis type 2 (NF2) related tumorigenesis into tools relevant for the treatment of the disease.

Dr. Giovannini's interview:

On May 25, 2011, representatives of Advocure NF2, Inc. visited Dr. Marco Giovannini at the House Research Institute’s Center for Neural Tumor Research. A plaque of Appreciation for HRI’s continuing NF2 research was presented to Dr. Giovannini and his laboratory colleagues. The following is a summary of the conversation between Dr. Marco Giovannini and Advocure NF2’s Roland Thoms and Sheila Heal.

Advocure: Dr. Giovannini, thank you for inviting us to your beautiful research lab this afternoon and for sharing your time with us. You have been working on NF2 research since 1994, starting at the Curie Institute in Paris. In 1999, the DoD NFRP consortium grant allowed Doctors K. Shannon, T. Jacks, L. Parada, A. McClatchey, and yourself, to develop the mouse models for NF2 and NF1 that exist today. Was that a critical step?

Dr. Giovannini: Absolutely yes. The results of that effort have been exceptionally successful by any measure. The NF Mouse Models Consortium generated accurate models of many NF1- and NF2-associated tumors and provided these mice to over 100 laboratories worldwide. Studies performed in these models by us and by other investigators have contributed fundamental insights into mechanisms of tumor formation and provided preclinical data that have led to novel drug trials. The strains produced through this effort are also the backbone of the Preclinical Consortium developed by the Children’s Tumor Foundation. This visionary series of competitive awards by the CDMRP has not only advanced our knowledge of NF1 and NF2 disease pathogenesis but has enabled our consortium to generate novel reagents that will help to advance the field for years to come. When I moved my lab to the House Ear Institute in 2008, I had the opportunity to access the largest population of NF2 patients in the US and to collaborate with Dr. Derald Brackmann, a leading surgeon for vestibular schwannomas. Our idea was to use the mouse models of NF2 to test drugs, based on the most recent knowledge of the molecular mechanisms of NF2, in order to identify new candidates to test in clinical trials. As a first approach, we focused on drugs that were already in advanced therapy development for other tumors.

On RAD0001:

At one point it became clear that we had one candidate that was outperforming other drugs, so we focused extensively on this drug (RAD001), a derivative of rapamycin, which has been extensively studied clinically and is FDA approved for several oncological indications, including Tuberous Sclerosis, a close relative of NF1 & NF2. We have tested this drug across all of our NF2 models, including the meningioma models that we have developed in collaboration with Dr. Michel Kalamarides in Paris. Based on the promising results, we approached Novartis clinical oncology team and they accepted to collaborate with us on a clinical trial with RAD001 for NF2 vestibular schwannoma (for info: ClinicalTrials.gov, study #NCT01345136). This drug has a good safety profile and excellent oral bioavailability that allows a once-a-day treatment over several months. We are very excited about this work since it is a unique example of translational research: going directly from basic science research studies to clinical research. We expect the clinical trial to begin in early 2012. At HRI, we are now screening patients for inclusion in the trial by analyzing our NF2 patients’ tumor growth over the past 12 months.

On Hsp90 Inhibitors:

Dr. G: We are also interested in another class of compounds, the inhibitors of Hsp90. The heat shock protein 90 (Hsp90), is necessary for the activity of many of the proteins which regulate several cellular processes and which are often mutated in cancers, as well as in NF2 tumors. Inhibiting the function of Hsp90 results in degradation of the mutated proteins, and prevents growth of cancer cells. The molecular chaperone Hsp90 is a promising new target in cancer therapy and selective Hsp90 inhibitors are currently in clinical trials. Our preliminary observations show that inhibition of Hsp90 blocks the growth of Nf2-deficient cells in culture and in vivo in NF2 mouse models. We are studying this further to provide enough evidence to support the further study of these drugs as therapeutics for NF2-related tumors.

This program was started in collaboration with NexGenix Pharmaceuticals, which is now developing highly potent HSp90 inhibitors in collaboration with the University of Strasbourg in France. Since then we have also tested Hsp90 inhibitors that are already being used in clinical trials to compare their potency in stopping the growth of NF2 tumors. Advo: Might you be poised for a clinical trial with an Hsp90 inhibitor within 5 years?

Dr. G: There are now several HSP90 inhibitors undergoing clinical evaluation, and 31 active HSP90 inhibitor oncology trials. Therefore, if we confirm efficacy in the various NF2 mouse models and if we identify an inhibitor with a good safety profile, we should be able to rapidly start a trial.

On EGF pathway Inhibitors:

Dr. G: In addition to these targets, several studies have shown that membrane receptors of the EGF family are abnormally activated in NF2 tumors and that pharmacologic inhibition of these receptors has an inhibitory effect in NF2 cells in vitro. These receptors exist on the cell surface and are activated by binding of specific ligands. As a result, downstream signaling proteins initiate several signal transduction cascades leading to DNA synthesis and cell proliferation. Mutations, amplifications or misregulations of EGFR or family members are implicated in about 30% of all epithelial cancers, and it is the target of an expanding class of anticancer therapies. In collaboration with Dr. McClatchey at Harvard, we found that one covalent EGFR inhibitor developed by Avila Therapeutics showed excellent and durable efficacy in cultured Nf2^-/- Schwann cells.

We are in the process of analyzing the efficacy of EGFR inhibitors in preclinical studies using our mouse models. A positive outcome from this study will provide the proof-of-concept evidence to support the use of covalent pan-ErbB inhibitors as a therapeutic option for NF2-related tumors.

On Natural compounds:

Advocure: Can natural compounds help people with NF2?

Dr. G: Today, about 80% of the world population residing in developing countries still rely almost entirely on plant products for their primary health care. The remaining 20% of individuals living in developed countries use, in more than 25% of cases, pharmaceuticals which have been directly derived from plant products. Throughout medical history, plant products have been shown to be valuable sources of novel anti-cancer drugs. The active principle is often present in a mixture of other compounds from a natural source and it has to be isolated and purified. As an example, Rapamycin was first discovered as a product of a bacterium found in a soil sample from Easter Island, also known as Rapa Nui, hence the name. The problem with non-purified natural anti-cancer compounds is that the bioavailability is often poor (Curcumin, Propolis) and multiple approaches including nanoparticles and liposomes are being sought to overcome this important limitation.

On Stem Cells:

Dr. G: In the case of NF we should not think of Stem Cell therapy as a replacement treatment, like in neurodegenerative diseases, but the notion of “Tumor Initiating Cells” is very important here since these cells are refractory to chemotherapy and radiation treatment and lead to recurrent tumors in patients.

Advo: What about the articles that report mouse spinal cord injury treatment with stem cell therapy?

Dr. G: Of course, it is tempting to think that stem cell therapy could be used to repair neurologic deficits resulting from schwannoma growth or facial nerve damage following microsurgery. We will have to follow closely the progress in nerve repair strategies to eventually apply them to NF2.

On Genomics:

Dr. G: Recent technological advances have made it feasible to sequence DNA on a large scale. The scale necessary for ambitious projects such as sequencing an entire personal or tumor genome is mostly done by high-tech machines, such as those that we have here at HRI. Much as your eye can scan a sequence of letters to read a sentence, these machines "read" a sequence of DNA bases. Each person has their own unique genome, that is, all of our DNA, which is unique to each human being. We have recently completed the first NF2 genome project, the sequencing of a NF2 patient “personal” DNA and one tumor from this patient. The comparison of the sequences of the two genomes will allow us to identify the gene mutations that are present only in tumor cells and that can influence tumor growth. For example, this analysis can shed light on why some NF2 tumors are slow and others are fast growing, and why some NF2 tumors stop growing while others progress and even become malignant. We also hope that studying entire genome sequences will help us understand how the genome as a whole functions, specifically, how genes orchestrate the growth, development and malignant transformation of a tumor. However, sequencing the NF2 patient and related tumor genomes does not immediately reveal their genetic secrets. We still have to translate those strings of letters into an understanding of how the genome works: what the various genes do, how different genes are related, and how the various parts of the genome are coordinated. For this bioinformatic analysis, we collaborate with Dr. Stan Nelson at UCLA's Jonsson Comprehensive Cancer Center. Dr. Nelson and his team help us to sort out and assemble that huge amount of sequencing data into useful information.

Obviously, these findings are not immediately applicable to people’s everyday lives, in terms of developing therapeutic treatments, but most fundamental research isn’t. The point here is that the first steps to understanding the genome of a tumor as a whole are being taken, which broadens our understanding of tumor development one step at a time.

Advo: What is the exome sequencing? How can this be applied to NF2?

Dr. G: Exome sequencing is a “lite” version of whole genome sequencing. Routine whole genome sequencing of large numbers of individuals is still not feasible partly due to the high cost associated with this technology. Therefore, it is necessary to use an alternative approach, in which only the parts of genome that contain genes (the “exome”) are sequenced. The “exome” represents all the exons (i.e., protein coding regions) in the human genome. In total there are about 180,000 exons in the human genome which represents about 3% of the entire genome. It is estimated that the protein coding regions of the human genome constitute about 85% of the disease-causing mutations.

On Gene Therapy:

Advo: Referring to gene therapy, could you speak about viral vectors? Could we use virus to deliver the “Merlin” protein into the cells of our patients?

Dr. G: Gene therapy uses viruses or other vectors to introduce new genetic material, such as a functional NF2 gene, or genes that render cells more susceptible to other therapies (drugs or radiation) into tumor cells. The major challenges have been delivery of DNA to a large number of target tumor cells and duration of expression of the gene. In addition, cancer can develop as a result of the insertion of the gene into a cell’s genome. As a result, the FDA has not yet approved any human gene therapy product for sale.

In contrast to “somatic” gene therapy, the concept of “germline” gene therapy is highly controversial. While it could spare future generations in a family from having a particular genetic disorder, such as NF2, it might affect embryo development or have long-term side effects that are unpredictable. Moreover, since individuals who would be affected by germline gene therapy are not yet born, they can’t choose whether to have the treatment. Because of these ethical concerns, the U.S. Government does not allow federal funds to be used for research on germline gene therapy in people.

On Synthetic NF2 Protein:

Advo: Can the NF2 protein Merlin, be produced synthetically?

Dr. G: Yes, it can. Again, the problem is how to get the synthetic protein inside tumor cells. The effectiveness of protein therapy has been limited by its low delivery efficiency and poor stability against proteases in the cell, which digest the protein. New approaches, including those based on nanocapsules, are currently evaluated that would allow proteins to be delivered to cells with high efficiency, while maintaining low toxicity.

On Short-Term and Long-Term Therapies:

Advo: Is the majority of your lab work at HRI focused on scientific, longer term discoveries, or shorter term therapies?

Dr. G: My lab’s focus in on translational NF2 research. Since we moved to HRI the effort has been equally shared between basic, pre-clinical, and clinical research.

Advo: You are close to bringing a new therapy if RAD001 performs as you expect it to. Is there more pressure on scientists to deliver short-term therapies?

Dr. G: There is pressure on scientists is to deliver therapies quickly for every disease for which there are only limited therapeutic options. However, I remain firmly convinced that the basic knowledge of the molecular mechanisms of NF2 tumor suppression will bring us the best treatments. Therefore, in my opinion patient-driven foundations, foundations such as Advocure NF2, should support both short and long term scientific projects.

Advo: Generally, researchers in basic science search for discoveries and answers to the vast unknown in order to answer the mysteries of NF2 - discoveries and knowledge that will take years to unravel. In doing this work, do we benefit in the short term for treatments and today’s quality of life?

Dr. G: Of course. If you look back even ten years, the clinical management of NF2 has dramatically improved, vastly due to this research. Now we know more about the growth pattern of these tumors, and there is more propensity to wait and see what the disease progression is before attempting any therapeutic intervention. Also, understanding the natural history and angiogenesis of NF2 tumors led to the use of anti-angiogenic drugs, such as Avastin.

So there are always advances along the way. They may not be revolutionary, but when you put them all together, and look back ten years, it is impressive. And when we look ten years forward, towards even more understanding that translates into better clinical management, it should be even more impressive.

On Information Sharing and Duplication of Efforts:

Advo: How do you feel about the sharing of information between NF2 doctors around the world? Do doctors duplicate efforts? Is that advantageous or an unwise use of resources?

Dr. G: In science and medicine, duplication of efforts is not necessarily a negative situation. On the contrary, it expands knowledge and information sharing among scientists is usually good. For example, we heard of some very remarkable successes in Europe with ABI implantation in NF2 patients, and soon after a team of neurosurgeons went to Europe to understand what was done differently. They were very open to learn and towards sharing information.

Sharing of information and knowledge is one reason behind the organization of the NF2: State of the Art meetings. In Paris, in 2006, with Dr. Kalamarides, we felt that it was important to convene with doctors interested in NF2 worldwide. Again, in May 2010, we hosted the NF2: State of the Art meeting, with Dr. Brackmann and Dr. Bob Shannon in Las Vegas followed by a CTF-sponsored workshop on NF2 clinical trials. A paper was just published in the Journal of Medical Genetics summarizing the outcomes of that meeting.

On Funding:

Advo: In speaking to the NF2 community regarding fundraising, what can we say to give the fundraisers an impetus to act?

Dr. G: We have seen tremendous progress since the identification of the NF2 gene in 1993. The last ten years have been amazing in terms of advances, discoveries, and potential application. The development of clinical trials, such as the one for Avastin was a big push forward. I would like to tell the community that we are a very dedicated group of people sharing the overarching goal of understanding and fighting NF2. Thus, we share with you the same objective: to find good and better therapies.

Advo: Does your lab need funding?

Dr. G: Due to the economic downturn of today, I think that all scientists I know are struggling for funding.

Advo: Is there one particular area or phase of research that needs funding more, since funding is so limited?

Dr. G: That is a very hard question. I believe all three of the major phases of therapeutic development for NF2 should be funded: Basic research, preclinical testing, and clinical trials for most promising drugs. In our experience, preclinical testing is by far the most difficult for which to procure funding.

Advo: How do you think that Advocure can help in getting funding to some of the needed work?

Dr. G: One way is to put pressure on Federal Granting Agencies to allocate funds to all three areas of NF2 research. We still need basic science to better understand the mechanisms and to identify the drug targets that are relevant for NF2, as well as preclinical research to validate them.