Jessie Villanueva, Ph.D.

The V Foundation MRA Young Investigator Award

Co-funded with The Melanoma Research Alliance

Although significant progress has been made treating melanoma and the recent approval of several drugs for the treatment of advanced disease, several challenges remain.  For example, clinical responses are generally short-lived as tumors quickly become drug resistant and patients relapse. Moreover, tumors can develop drug resistance through a diverse number of molecular mechanisms, making the development of second-line therapies extremely daunting.  Therefore, it is critical to identify therapeutic targets that are common to the majority of resistant tumors.  We have recently found that a protein kinase called S6K is activated in melanomas resistant to BRAF and MEK inhibitors.  Moreover, we showed that inhibition of this protein using a triple drug combination blocked the growth of resistant tumors.  This provides strong rationale for establishing S6K as a novel target for melanoma therapy.  Notably, S6K is a common node for most resistance pathways.  We propose to investigate the role of S6K in melanoma and determine the therapeutic value of targeting this protein.  Towards these goals we will determine the consequences of blocking S6K in melanoma, identify the proteins that are regulated by S6K and use this knowledge to delineate combinatorial approaches that can lead to long-term tumor remission in a large number of melanomas, including those resistant to BRAF and MEK inhibitors.  We expect that the data generated by these studies can be quickly translated into new strategies aimed at maximizing the therapeutic efficacy of MAPK inhibitors in melanoma and provide actionable information that will guide the design of future clinical trials. 

Sabine Mueller, M.D., Ph.D.

Vintner Grant in Memory of Shunsuke Yamamoto

Children with diffuse intrinsic pontine glioma– a specific brain tumor type- continue to have a dismal prognosis and most children die from this disease within months from diagnosis.  Despite multiple national clinical trials, no change in outcome has been achieved over the last several decades. Two potential reasons why we have not made any progress in this disease are a) treatment is not matched to each child’s individual tumor characteristics and b) due to the presence of a tight blood-brain barrier medications given either by mouth or vein are not getting in sufficient enough concentrations to the tumor. To address these issues we are currently conducting a clinical trial through the Pacific Neuro-Oncology Consortium (www.pnoc.us, PNOC003). In this trial we will profile each child’s tumor with state of the art next generation sequencing and determine a treatment plan based on the specific characteristics of the tumor. A specialized tumor board that consists of several neuro-oncologist, pharmacologists and researches with an expertise in next generation sequencing meet and discuss the results and determine a specialized treatment plan, which consists of up to four FDA approved drugs. Specific attention is being paid to the drug brain penetration of recommended drugs. Correlative aims of this feasibility study is to develop patient derived mouse models as well as to test if tumor specific DNA can be detected in blood and be used as a marker for clinical response.

John Cavanagh, Ph.D.

Recently, researchers in the program have discovered a synthetically accessible class of molecules that appear to increase the effects of novel anticancer drugs by several orders of magnitude.  The overarching goal is to reduce the working concentrations of ALL anti-cancer drugs in order to mitigate serious side effects.  Here, we propose to develop and screen our new molecules with both novel and existing chemotherapeutics against a variety of cancer cell lines in order to define the optimum combination treatment. 
 
Also we are working on tumor formation. 
 
The life and death of cells must be balanced if tissue homeostasis is to be maintained-there should neither be too much growth nor too little death.  Normal cells accommodate this balance by invoking intrinsic programmed cell death, referred to as apoptosis.  Apoptosis is triggered via three signaling pathways.  If apoptosis does not occur correctly and cells do not die, then malignant tumors form.  It is no surprise therefore that countless cancer therapeutics are being developed to control apoptosis. 
 
It is known that all three apoptosis signaling pathways route through a protein known as caspase-3.  If caspase-3 fails to function, then cell death does not happen correctly and cancer occurs.  It is known that a calcium-binding protein known as calbindin-D28K binds to caspase-3 and stops it functioning.  If we can stop calbindin-D28K from interfering with caspase-3, apoptosis would occur normally and the risk of cancer developing would be significantly reduced.  Consequently calbindin-D28K is a particularly powerful target for anticancer drug development. 

Hui Li, Ph.D.

Co-Funded with St. Baldrick’s Foundation

Alveolar rhabdomyosarcoma is one of the most common children tumors.  No effective therapy is available for advanced disease.  Poor understanding of the etiology of the tumor is partly responsible for the lack of advancement in treatment.  We are using tumor-signature events to study the cell of origin for the disease.  Our results may shed light on the development of the tumor, and potentially lead to better diagnostic and therapeutic tools. 

Qing Li, M.D., Ph.D.

Leukemia stem cells (LSCs) are able to regenerate leukemia after chemotherapy and cause leukemia relapses.  LSCs are transformed from the normal blood stem cells by mutations.  We found that one of the commonly found mutations NRAS is able to re-program the signaling pathways in normal blood stem cells and chamge them into LSCs.  Our studies showed that Nras does this through an unexpected pathway and targeting this pathway may lead to elimination of LSCs to potentially cure leukemia. 

Angela Fleischman, M.D., Ph.D.

Myeloproliferative neoplasm (MPN) is a chronic leukemia characterized with no curative treatments other than bone marrow transplantation. MPN results from the acquisition of a mutation in a blood stem cell that drives the unrestrained production of myeloid blood cells. Mutations in the gene calreticulin have been recently identified in a large proportion of MPN patients, it is currently unknown how calreticulin mutations drive MPN. Our goal is to identify the mechanism by which calreticulin mutations cause the manifestations of MPN and to develop drugs targeting calreticulin to treat this disease.

Megan McNerney, M.D., Ph.D.

Each year, in the U.S. alone, over 50,000 people are diagnosed with myeloid cancers of the blood. Some myeloid cancers have been found to lose all or a portion of chromosome 7 [-7/del(7q)], and these cases are particularly difficult to treat. The overall survival for these patients is less than one year. -7/del(7q) also occurs in half of therapy-related myeloid neoplasms/cancers (t-MN). t-MN arise as a side effect of chemotherapy/radiation and occur in u to 8% of cancer survivors. There is clearly an urgent need to develop better therapies for -7/del(7q) disease. It has long been thought that one or more genes on chromosome 7 prevents cancer growth – “tumor suppressor genes.” I used genomic technologies and animal models to map this tumor suppressor gene, implicating CUX1.  The long-term goal of the current proposal is to improve the outcome for patients with this type of disease. This proposal is designed to accomplish this by identifying CUX1-regulated pathways that may be potential drug targets as well as establish animal models for future use in preclinical therapy development. The contribution of the proposed research is expected to bhe characterization of the biological outcomes and altered pathways caused by CUX1 loss–the first step toward developing therapies. The significance of this work is not limited to leukemia; CUX1 is mutated in endrometial cancer, gastric cancer, and melanoma, among other tumors. Thus, the understanding of CUX1 function in myeloid disease may guide our knowledge of the role of CUX1 in other cancers.

 

Wenjun Guo, Ph.D.

Cancers are a diverse collection of diseases that are caused by distinct gene mutations. Effective cancer treatment has to be tailored for these patient-specific aberrations. To this end, the cancer genome project has systematically identified mutations in various cancer types and provided a foundation for personalized cancer medicine. However, the cancer genome can be littered with mutations simply due to the fact that cancer cells are highly unstable. Therefore, it is critical to understand which mutations play a causal role in driving cancer progression, i.e. acting as drivers, and which mutations are merely bystanders.

To address this question, we have developed a novel technology for generating personalized breast cancer models that contain mutations found in human patients. Using these models, we will decipher which mutations are functional important, and thus can be useful therapeutic targets. Our work is like to identify novel breast cancer genes and provide new therapeutic targets and biomarkers for selecting most effective treatment.

Successful outcomes of our study will pave the way for developing therapeutic agents for targeting these new breast cancer genes. In addition, the technology perfected through this study will be highly valuable for investigating mutations of other cancer types to identify a catalog of cancer targets that can be tailored for personalized medicine.

Emily Dykhuizen, Ph.D.

Kidney cancer is the 8th most common cancer in the USA, representing 3% of new cancer cases each year and 4% of cancer deaths. Renal cell carcinoma (RCC) is the most common and lethal type of kidney cancer in adults, representing 90-95% of all kidney cancer cases. Approximately 90% of RCCs have mutations in the tumor suppressor gene, von Hippel-Landau (VHL), which is involved in the degradation of hypoxia-inducible factor (HIF) transcription factors. The mutation of VHL leads to huge increases in the levels of HIF, which promotes tumor growth by increasing the blood supply to tumors. Uncovering this pathway of tumor suppression has led to several targeted therapeutics that lower levels of HIF, and are currently used in the clinic. While this has improved the outcome for RCC, the median survival rate for metastatic renal carcinoma patients is still only 22 months. Uncovering additional mechanisms of tumor suppression and new therapeutic targets would bring us closer to our goal of eradicating these cancers. To this end, efforts to identify additional genes mutated in RCC have identified Polybromo-1 (PBRM1) as the second most commonly mutated gene in RCCs (~50%). PBRM1 is part of the SWI/SNF (BAF) chromatin remodeling complex, an important regulator of gene expression. While subunits of the BAF complex are mutated in a spectrum of cancers, mutations in PBRM1 seem to be fairly specific to RCC. We aim to understand the mechanism of tumor suppression by PBRM1 in RCC by 1) uncovering how PBRM1 deletion affects the function of the BAF chromatin remodeling complex, 2) identifying genes regulated by PBRM1 deletion, and 3) identifying pathways important in RCC progression that we can target with novel or known therapeutics.

Mazhar Adli, Ph.D.

Aberrant chromatin regulation is a hallmark of multiple developmental diseases including cancer. Various chromatin marks such as DNA methylation and histone modifications, known as “epigenetic marks”, are implicated in the dynamic regulation of chromatin structure and lineage specific gene expression. Epigenetic regulators are recurrently mutated in cancer. The reversible nature of epigenetic marks holds great therapeutic promise. Therefore much effort is devoted to developing small molecule epigenetic inhibitors however such approaches are targeting the entire genome, causing multiple unintended side effects. I am proposing to develop tools that enable locus-specific manipulation of chromatin structure and function. Bu using such locus specific epigenetic engineering tools, I aim to alter aberrantly regulated local epigenetic modifications at specifically targeted genomic region.

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