Research

The Hu lab studies clinically relevant problems in cancer. Most of our cancer studies have been done in prostate cancer, however we have begun studies on lung cancer cells and plan on expanding to pancreatic and other cancers in the future. As the lab focuses on clinically relevant questions, we are not restricted to only using particular techniques, studying one protein or pathway, or studying one disease model. Instead, we adapt our studies to answer these questions. We use several different approaches including biochemical, structural, molecular, cellular, imaging, genetic, mice studies, 'omics', clinical patient analysis, and bioinformatics. Therefore each current and potential lab member brings their own strengths to help the whole lab succeed.

 

The Hu lab has several research programs that are integrated with technology development,
basic biological research, and clinical translation.

  • Technology developments: Current technology developments involve bimolecular fluorescence complementation (BiFC) and BiFC-derived technologies add a link to the BiFC tab. The lab is always interested in adapting current technologies and new method development and have published several methods papers. The lab also stresses optimizing protocols and not simply repeating previously published protocols which directly translates to the trustability and reproducibility of our results.

  • Basic biological research: The basic biological research is centered on the molecular mechanisms of cancer development, progression, growth, and response to treatment. Current work focuses on the transcriptional and epigenetic regulation of cancer cell growth and cellular response to cancer therapeutics including DNA damaging agents and radiation therapy. Our studies include structural and biochemical characterization of proteins in different complexes, analysis of gene regulation, analysis of signaling pathways, and analysis of the DNA damage response.

  • Clinical translation: The translational research is aimed at identifying and assessing potential therapeutic targets in cancer as well as developing novel targeting strategies. Current work focuses on inhibiting cancer cell growth, inhibiting cancer cell differentiation in response to treatment, sensitizing cancer to DNA damaging therapies, and developing co-targeting strategies to improve current cancer treatments. Our studies include validation in mouse models (genetic models and xenograft studies) as well as analysis of clinical samples and publicly available cancer data sets. The key is to make our research meaningful and gives the potential for our findings to be translated to a clinical study.

Specific Research Areas

(1)   Targeting radiation therapy-induced neuroendocrine differentiation (NED) in prostate cancer. 

Using fractionated ionizing radiation (FIR) to mimic clinical radiation therapy of prostate cancer cells (2 Gy/day, 5 days/week, 7 weeks), we found that although almost all cells died, the surviving cells differentiated into neuroendocrine-like (NE-like) cells. Differentiation into NE-like cells occurs via neuroendocrine differentiation (NED). Clinical NED in prostate cancer is emerging as an aggressive, treatment-resistant end-stage. Because NED is reversible, our findings suggest that radiation-induced NED may represent a mechanism by which prostate cancer cells survive radiation therapy and contribute to recurrence. We have identified several critical transcriptional and epigenetic regulators of radiation-induced NED (Cancer Res, 2008, Am J Cancer Res, 2011 and 2014). Our goal is to further validate these critical regulators of NED and identify and characterize other therapeutic targets for the development of novel radiosensitizers. We are also expanding our work to assess the mechanisms of other treatment-induced NED (not just radiation) and in other cancers.

 

(2) Role of PRMT5 in prostate cancer development, progression, and therapeutic response. 

Using a proteomic approach, we identified protein arginine methyltransferase 5 (PRMT5) as a potential regulator of radiation-induced NED. We recently published work demonstrating that PRMT5 plays an integral role in the repair of DNA damage and that targeting PRMT5 sensitizes cells to radiation (Owens, iScience 2019). We have also discovered that PRMT5 is an important epigenetic regulator of prostate cancer cell growth by epigenetic activation of androgen receptor (AR) expression (Deng, Oncogene 2017). Our goal is to elucidate the role of PRMT5 in prostate cancer development, progression, growth, and response to treatments.

(3)   Development of novel technologies to visualize, image, and target transcriptional and epigenetic regulation.

Many transcription factors form dimers among family members to bind DNA and regulate gene expression. Although using a genetic approach has been the gold standard to analyze the role a gene in vivo, there are several potential drawbacks with knocking-down or knocking-out a gene for its study. We have been developing a series of BiFC-based technologies to visualize and target transcription factor dimers, rather than individual proteins or genes. We will continue to explore novel BiFC applications in the context of cancer. These applications include, but are not limited to, BiFC-based biosensors, high throughput screening for protein-protein interaction disruptors, and BiFC-based interactomes. We believe the development and application of novel technologies will allow us to identify molecular targets and pathways for the development of novel cancer therapeutics.  

 

(4)    Regulation and function of AP-1 in prostate cancer cells.

AP-1 is a transcription factor that functions as a dimer of various proteins such as c-Jun, c-Fox, and ATF2. Using our novel technologies such as BiFC, we are investigating how various combinations of proteins in the AP-1 dimer function in mammalian cells. We are also performing genetic studies in C. elegans as a model to assess the role of AP-1 dimers in vivo. The lab has published several studies regarding the role of AP-1 dimers and their target genes. We are currently investigating the mechanisms and functional consequences of AP-1 protein regulation (changes in expression and subcellular localization) in prostate cancer cells

 

(5) Development of protein-protein interaction (PPI) disruptors as novel cancer therapeutics. 

PPIs are critical to almost all cellular processes from signal transduction to gene regulation. PPIs unique to cancer cells represent an attractive, though challenging, therapeutic target. We have been employing BiFC-based approaches to identify and characterize cancer-specific PPIs. These PPIs can also be unique to particular contexts. For example, some proteins may only interact in response to treatment such as radiation. Additionally, the role of a protein may be dependent on which protein it interacts with. Therefore a PPI disruptors potentially have less systemic side-effects than an enzymatic inhibitor. As we have identified some critical PPIs, in collaboration structural biologists we are identifying and characterizing critical PPI interphases that may be targeted via inhibitors. For an unbiased approach, in collaboration with computational biologists and medicinal chemists we are currently developing a BiFC-based high throughput screening approach to screen for inhibitors of several unique PPIs that regulate prostate cancer growth and radiation response. 

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