January 25, 2016
It's been going strong for a decade now. Since its inception in 2005, the Patrick C. Walsh Prostate Cancer Research Fund has awarded millions of dollars to Johns Hopkins scientists in every discipline with good ideas worth pursuing that can help us understand more about prostate cancer — and help us save lives with better ways to treat and prevent it.
Applications are reviewed by a Scientific Advisory Board composed of noted Hopkins scientists and lay members. These awards wouldn't have been possible without the tremendous and amazing generosity of our patients and friends.
Here you'll find some of the exciting work this year's award winners are doing, which wouldn't be possible without your help.
Understanding Prostate Cancer Progression During Active Surveillance
Urologist H. Ballentine Carter has done pioneering research in prostate cancer for decades, but he's never talked about it like this: Think of low-risk prostate cancer as a turtle, intermediate-risk cancer as a rabbit, and high-risk cancer as a bird, he says. "The classification depends in large part on the cancer grade. If turtles, rabbits and birds were put into a fenced area (the prostate), the turtles would never leave, or spread to other parts of the body. The rabbits would sometimes leave, and the birds would often leave."
Carter has been thinking about the different risk levels of prostate cancer particularly as it has to do with low-risk cancer – the men who qualify for the Active Surveillance program, which he began 15 years ago and continues to lead. With funding from the Patrick C. Walsh Prostate Cancer Research Fund, Carter has teamed up with some impressive Hopkins co-investigators — geneticist William Isaacs, pathologists Angelo De Marzo, Srinivasan Yegnasubramanian, Jonathan Epstein and Michael Haffner, and mathematical analyst and scientist Sarah Wheelan. "The purpose of this project is to determine whether turtles can evolve into rabbits and birds," says Carter. The scientists have identified men in the Active Surveillance program who were initially diagnosed with low-grade disease, but during the close follow-up turned out to have high-grade cancer found on a repeat biopsy, which resulted in radical prostatectomy. Using those pathology specimens, "the low-grade 2016and high-grade components of the cancer within the same prostate will be genetically sequenced to determine how these cancer cells are related," says Carter. The scientists hope that by making a "genetic fingerprint" of these tumors, they can answer some key questions, including: Did the low-grade cancer somehow morph into high-grade disease, or did both low- and high-grade disease just happen to spring up together? Do these high-grade cancers leave some sort of calling card — a genetic marker that could be used to predict whether men have cancers that are actually birds in turtle clothing? The investigators will also look at a control group — low-grade cancer that has remained low-grade, "to determine if there are high-grade markers within these low-grade cancers," Carter continues. "Lastly, if we find definitive markers of high-grade cancer within low-grade cancer, we will sequence prostate biopsies to determine if disease that we diagnosed as low-grade actually contained high-grade markers. This information could help men with a diagnosis of low-grade cancer know whether they will eventually need treatment."
Prostate Biopsy: Can a Robot Make it Better?
Misop Han, M.D., the David Hall McConnell Professor of Urology, believes that prostate biopsies don't provide enough information. "A typical transrectal ultrasound (TRUS)-guided biopsy has significant limitations," he explains, "because the probe is handled by human hand." In new research funded by the Patrick C. Walsh Prostate Cancer Research Fund, he and his co-investigators, robotics expert Dan Stoianovici and epidemiologist Bruce Trock, plan to improve TRUS-guided prostate biopsy with a novel robotic TRUS manipulator (called a TRUS Robot), "which was developed in our laboratory."
With robotic guidance, Han believes, the TRUS-guided biopsy will not only be able to provide important information about the precise location of the biopsy cores, but about the stiffness of the prostate. As urologist Patrick Walsh explains, the prostate should feel soft in a digital rectal exam, "like the pad of your thumb. But if there is cancer, it feels harder," more like a knuckle. The biopsy needle can't feel; but Han hopes to fix this: "With the TRUS Robot, we are incorporating a new imaging modality, ultrasound elastography, which can detect the relative stiffness of the prostate. With elastography guidance, regions of elevated relative stiffness will also be included in the biopsy plan," to make the urologist aware of any "trouble spots" that may need further investigation.
Targeting Prostate Cancer Cells That Hibernate
When cancer escapes the prostate, some cells go to the bone marrow, where they are alive but dormant. "These sleeping cells are resistant to conventional therapy," says scientist Sushant Kachhap, Ph.D., which means that if they wake up and cancer begins to grow outside the prostate, "there are very few therapeutic options."
Kachhap is intrigued by these hibernating prostate cancer cells. What makes them sleep? What wakes them wake up? "While we know a great deal about how cancer grows, very little is known about the biology of prostate cancer dormancy," he says. "This makes targeting these dormant cells a challenge, but also extremely important." Kachhap believes that the ability to become dormant is acquired "very early in the process of metastasis, when prostate cancer cells leave the prostate and enter the bloodstream."
The dormancy seems to have a protective effect — think of Sleeping Beauty, who managed to sleep for 100 years and hadn't aged a day when the prince woke her up. "Normally, when cells break off from the parent organ, they die due to a mechanism called anoikis. But detached prostate cancer cells survive by signaling a process called autophagy, where parts of the cell are broken down and the energy is used for survival." In research supported by the Patrick C. Walsh Prostate Cancer Research Fund, Kachhap will use cell and animal models to investigate what triggers dormancy in prostate cancer cells — whether it's caused by breaking off from the main tumor, or by autophagy, or something else. "Moving forward, we will test whether inhibiting autophagy can lead to death of dormant prostate cancer cells. We believe this work can lead to new strategies for targeting dormant prostate cancer cells, and inhibiting metastatic cancer."
Who Can Benefit from Drugs That Stop Cancer Cells from Repairing Themselves?
Anthony Leung, Ph.D., an RNA biologist, is interested in drugs that inhibit PARP. PARP — which stands for poly (ADP- ribose) polymerase — inhibitors have shown promise in treating ovarian, breast, and prostate cancers. "These drugs are designed to target cancers that already have defects in their ability to repair DNA, and rely on remnant repair pathways for survival," he says. "These remnant pathways are mediated by PARP; so by blocking these pathways, scientists can kill cancer cells but spare healthy cells with functional DNA repair." PARP-inhibiting drugs have been shown to extend life and even cause tumors to go into remission in patients with mutations in the DNA repair genes BRCA 1 and 2. "PARP inhibitors have also shown survival benefits for other patients with difficult-to-treat, castration-resistant prostate cancers," says Leung. In an ongoing Phase II trial of Olaparib, men with advanced, castration-resistant prostate cancer have shown impressive responses, he adds. "This trial includes patients who have not inherited BRCA mutations, but do carry mutations to DNA repair genes within their tumors. These encouraging data suggest the possibility of expanding access to PARP inhibitors to patients with other defects in DNA repair pathways." But will they respond? "So far, scientists have not been able to predict who will benefit from this drug," says Leung. "At the same time, it is equally important to find out which patients are not responding, so as to avoid unneeded treatments — and, more importantly, false hope in patients. Therefore, we urgently need a sensitive tool that is able to distinguish responders from non-responders."
With support from the Patrick C. Walsh Prostate Cancer Research Fund, Leung hopes to develop such a tool, along with Hopkins co-investigators Ken Pienta, H. Ballentine Carter, and Robert Cole; and Phillip Sharp, of the Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology. "As its name implies, a PARP inhibitor stops the PARP enzyme from working," explains Leung. "PARP works by putting a specific mark on proteins. In cancer cells, the abnormal activity of PARP even adds marks to proteins that are normally unmarked." To scientists looking at proteins, such marks are the equivalent of signposts, and "we predict that people who will respond to these drugs will have a distinctive set of protein marks. Thus, the ability to identify these protein marks may likely be the key to predict which patients will respond well to PARP-inhibiting drugs. Recently, our lab published a highly sensitive method to identify such protein marks. We are now geared to apply our method to a panel of prostate cancer cell lines." Some of these cancer cells are killed by PARP inhibitors, and some are not. "Using these data, we will be able to identify which protein marks can distinguish responders from non-responders." Leung hopes this work will identify a biomarker that can be used in a blood test to help determine which men will benefit from PARP-blocking drugs.
Ultra-Precise Targeting and Killing of Metastatic Prostate Cancer
Radiopharmaceutical therapy is an ultra- precise way of targeting and treating cancer cells. Scientist Sangeeta Ray, Ph.D., is integrating molecular PET and CT imaging, "with the ultimate goal of tumor-specific treatment of castrate- resistant prostate cancer."
With support from the Patrick C. Walsh Prostate Cancer Research Fund, Ray and co-investigator Martin Pomper are developing a very specific, low-molecular- weight "theranostic" agent. Theranostic is another new word you may be seeing more of; it's a combination of therapeutics and diagnostics, and it's a key term in the growing field of personalized medicine. Ray's goal is "to treat multiple sites of disease simultaneously, minimizing damage to adjacent normal tissue, and to treat metastases at an earlier point, when the volume of disease is lower," she says. "Currently, this is challenging to achieve with standard external-beam therapy." Ray is aiming to develop an imaging agent that targets a molecule on the surface of prostate cancer cells, PSMA (prostate-specific membrane antigen). What will happen next in cancer cells is akin to lighting up a gun's target with a laser sight – making them much easier to see and kill. "Based on our preliminary studies, the underlying hypothesis is that the low- molecular-weight agents can be optimized to demonstrate superior tumor penetration and lower toxicity to normal tissues, particularly the kidneys, and to provide greater therapeutic efficacy than currently available treatments."
Studying the Molecular Switches for Metastasis
You may soon be hearing more about a protein called HMGA1. A tiny thing, it is nonetheless critical for rapid growth and development before birth. Normally, it is switched off or silenced in our cells after birth, but becomes abnormally flipped back on in aggressive cancer cells. During fetal development, it helps to maintain the structure and function of the cell's nucleus, its command post that houses our genetic material and directs the behavior and function of cells throughout our bodies. "Much like 23a quarterback on a football team, the nucleus tells the cell either to remain in place or move, or to progress into a more specialized position," explains molecular biologist Linda Resar, M.D. "The nucleus also dictates whether a cell will grow and divide, or remain quiescent."
In work supported by the Patrick C. Walsh Prostate Cancer Research Fund, Resar and co-investigators Robert Veltri and Karen Reddy are studying HMGA1 in prostate cancer. Resar's laboratory discovered that HMGA1 transforms normal cells into aggressive cancer cells. "Moreover, HMGA1 is a marker of poor outcomes for patients with diverse tumors," she says. "HMGA1 is present in high levels in aggressive prostate cancers, and it drives tumor cell invasion and aggressive behavior in animal models of cancer." Resar discovered that HMGA1 functions as a key molecular switch that cancer cells need to grow rapidly and spread. "Our preliminary studies suggest that HMGA1 alters nuclear shape and function to flip on genes that enable prostate cancer cells to leave their primary site, invade and metastasize."
Resar and colleagues are conducting innovative studies to determine precisely how HMGA1 causes changes to the shape and function of the nucleus, "and whether we can use these alterations to predict which tumors will behave aggressively in men with prostate cancer. We will also uncover the genes and pathways that are turned on by the HMGA1 switch to transform normal prostate cells into invasive cancer cells." If the investigators can crack the code of how HMGA1 works, they will determine whether these changes can predict tumors that are likely to behave aggressively and move to distant sites. They also hope to develop approaches to target or block these changes in therapy. "Together, our team will define the role of HMGA1 in nuclear structure and function in prostate cancer," she says. "Results generated here will lay down the groundwork to determine whether HMGA1 and its role in nuclear reprogramming can be used to predict outcomes and optimize therapy for men with prostate cancer."
Prostate Cancer Screening: Is There a Better Way?
Prostate cancer screening is not specific enough — even though there are new tools today that might reduce the risk of over-diagnosis, says urologist Ashley Ross, M.D., Ph.D. He believes that one diagnostic test, in particular, shows great promise: "Multi-parametric" MRI (mpMRI), which can show clinically significant cancer. "Though mpMRI is being integrated into clinical practice, it has not been rigorously compared to standard prostate cancer screening," he says. How good is it? Ross, with co-investigators H. Ballentine Carter and Craig Pollack, aims to find out. "Our hypothesis is that using mpMRI in men with elevated PSA may decrease unnecessary biopsies and the diagnosis of clinically insignificant prostate cancer — which doesn't need to be treated — with minimal under- diagnosis of clinically significant cancer."
To do this, Ross and colleagues will design and perform a randomized trial. Half of the men will be those who, like millions of American men, undergo standard PSA testing and receive a transrectal ultrasound biopsy if the PSA is elevated. The other group of men will get the same PSA testing, and then will undergo mpMRI, a painless, noninvasive procedure, before biopsy. "For those undergoing MRI and then biopsy, biopsy will be performed with MRI- ultrasound fusion technology." In addition, the group will assess the usefulness of biomarkers that recently have come into clinical practice, and determine the cost-effectiveness of the two screening strategies. "The results of this trial will have immediate implications as to how we screen men for prostate cancer."
Improving Control of Cancer in the Bones
One of the worst features of advanced prostate cancer is bone metastasis. A new agent called Radium-223 dichloride has shown success here; it is an alpha particle-emitting radionuclide that is incorporated in the bone material. It emits highly toxic alpha particles that kill cancer in the bone; however, it has a very short range. In fact, it only kills the cells directly next to it in the bone. In research supported by the Patrick C. Walsh Prostate Cancer Research Fund, nuclear medicine scientist Daniel Thorek, Ph.D., with co-investigator Ryan Riddle, hopes to find out exactly how Radium-223 works at sites of bone metastasis.
"In initial studies, we have developed small animal models of prostate cancer metastasis in the bone, and we are performing high-resolution imaging to evaluate the magnitude and microdistribution of the agent," says Thorek. The investigators are evaluating the effect of the Radium-223 on the bone and prostate cancer cells at the sites where the radionuclide is deposited. "This may provide insight into improving dosing, in order to achieve an optimal therapeutic effect on the prostate cancer cells, with minimal surrounding bone cell damage." They also plan to use high-resolution, noninvasive nuclear imaging to show how Radium-223 is distributed. "This may provide a means to personalize the application of this radionuclide in men with prostate cancer."
Creating a Vaccine Against Prostate Cancer
Can a man be inoculated against his own prostate cancer? Scientist Raphael Viscidi, M.D., along with co-investigators Brian Simons and Ashley Ross, hopes to find out. "Because the disease can be diagnosed early and the prostate expresses tissue-specific proteins that can be the target of vaccines, we are investigating the value of a novel vaccine for prostate cancer in an animal model," says Viscidi. To make the vaccine, they are using a virus — actually, part of a virus, a protein that has the ability to form a large particle. "The outer surface of the particle can be decorated with short proteins," — think of sprinkles on a cupcake — "and these will be derived from tissue-specific proteins made by prostate cancers. We have shown that these novel particles can induce immune cells," enlisting the body in the fight against prostate cancer.
"The physical properties of the particles make them very potent inducers of cellular immune responses," Viscidi explains. "Unlike most other vaccines, they can be administered on their own to induce immune responses. We are using three tissue-specific proteins made by prostate cancers: prostatic acid phosphatase, prostate stem cell antigen, and stimulator of prostate adenocarcinoma-specific T cells." In work supported by the Patrick C. Walsh Prostate Cancer Research Fund, the investigators will dot the surface of the vaccine particles with small proteins known to specifically stimulate the immune system of mice.
What the team is doing, trying to work around prostate cancer's impressive ability to defend itself, is like a molecular game of chess. The technology is there; now the key is to figure out the best strategy. For example, Viscidi says, "cancers have recently been shown to block immune responses by expressing inhibitory proteins." Two of these proteins are CTLA4 and TIM-3. But in a counter move, scientists have developed antibodies that block these proteins. Will it strengthen the immune response if the investigators combine their vaccine with these anti-CTLA4 and anti-TIM-3 antibodies? They plan to find out, using a model known as the TRAMP mouse. "The advantage is that these spontaneously develop cancer in the prostate gland. We will treat mice of various ages, representing stages of prostate cancer from small lesions to metastatic disease, with our vaccine alone or in combination with anti-CTLA4 and anti-TIM-3 antibodies. If the vaccine proves successful in treating cancers in the mouse model, we plan to construct a similar vaccine using human prostate-specific proteins, and test it in men with prostate cancer."
Looking For a "Smart" Urine Test for Prostate Cancer
As helpful as PSA testing has been for millions of men, it does not always tell doctors which man's cancer is lethal, which man's cancer is indolent, and which man doesn't have cancer at all, but another prostate problem that is causing his PSA to rise. In work funded by the Patrick C. Walsh Prostate Cancer Research Fund, scientist Hui Zhang, Ph.D., along with co-investigators Robert Veltri and Bruce Trock, believes these answers may be found in specific proteins in the urine.
Glycoproteins are proteins that have carbohydrates attached to them. "We hypothesize that glycoproteins specifically altered in aggressive prostate cancer cells can be released to urine and used as biomarkers," says Zhang, "to distinguish men with lethal cancer from those with indolent prostate cancer." The scientists hope to identify these using quantitative analysis, looking at urine glycoproteins from lethal and indolent prostate cancer, and then testing these potential biomarkers using glycoproteomic analysis. The end result, they hope, will be a noninvasive urinary test. "Urine biomarkers capable of distinguishing lethal from indolent prostate cancer will help men with lethal prostate cancer to receive appropriate treatment earlier, and help prevent overtreatment in men who have indolent disease."
H. Ballentine Carter, M.D., The Carolyn and Bill Stutt Scholar, Departments of Urology and Oncology
Misop Han, M.D., The Nancy and Jim O'Neal Scholar, Departments of Urology and Oncology
Sushant Kachhap, Ph.D., Department of Oncology
Anthony K.L. Leung, Ph.D., The Irene and Bernard L. Schwartz Scholar, Departments of Biochemistry& Molecular Biology and Oncology
Sangeeta Ray, Ph.D., The Dr. and Mrs. Peter S. Bing Scholar, Department of Radiology and Radiological Science
Linda Resar, M.D., The Peter Jay Sharp Foundation Scholar, Departments of Medicine, Oncology, and Institute for Cellular Engineering
Ashley Ross, M.D., Ph.D., The R. Christian B. Evensen Scholar, Departments of Urology, Oncology and Pathology
Daniel Thorek, Ph.D., Department of Radiology
Raphael Viscidi, M.D., The Beth W. and A. Ross Myers Scholar, Departments of Pediatrics and Oncology
Hui Zhang, Ph.D., The Virginia and Warren Schwerin Scholar, Department of Pathology