Taking a Novel Look at an Established Agent: Malaria Drug Chloroquine Studied in a Preventive Setting for Early DCIS

OncologyLive, April 2012, Volume 13, Issue 4

In this interview, Lance A. Liotta, MD, PhD, discusses the hypothosis that led to the study and the research thus far into chloroquine.

Lance A. Liotta, MD, PhD, addresses attendees in Miami Beach.

As mammography has grown increasingly sophisticated, the incidence of ductal carcinoma in situ (DCIS) has risen dramatically. Indeed, the diagnosis of DCIS has grown from a relatively rare finding in the 1970s to up to 25% of all breast cancers by 2004, according to the federal Agency for Healthcare Research and Quality.

In recent years, some researchers have expressed concerns about overdiagnosis and overtreatment of DCIS, suggesting that a preventive approach that includes active surveillance might be appropriate for lower-grade lesions.

Taking a different view is Lance A. Liotta, MD, PhD. He believes DCIS lesions, even at low grades, can hold the seeds for invasive cancers.

Liotta has been researching the stages of cancer metastases and tumor cell—extracellular matrix interactions for 40 years. He formerly served as chief of the Laboratory of Pathology at the National Cancer Institute and as a deputy director at the National Institutes of Health. Since 2005, he has served as co-director of the Center for Applied Proteomics and Molecular Medicine at George Mason University in Manassas, Virginia.

His current research focus includes potential uses for chloroquine, an oral small-molecule compound used in the United States to treat patients with malaria since the late 1940s. Based on experiments conducted by his research colleague Virginia Espina, MS, an assistant professor, the team has been exploring chloroquine as a neoadjuvant therapy for DCIS and as a potential means to kill preinvasive breast lesions. The clinician of the research team is Kirsten H. Edmiston, MD, a breast surgeon and medical director of the Inova Breast Care Institute in northern Virginia.

The group is seeking to enroll 90 patients in a clinical trial testing the efficacy of chloroquine in 500-mg/wk and 250-mg/wk doses as a neoadjuvant therapy for DCIS. The trial, listed on the Clinical Trials.gov website (NCT01023477), is sponsored by the US Department of Defense Breast Cancer Research Program (DOD BCRP).

In this interview, Liotta discusses the hypothosis that led to the study and the research thus far into chloroquine.

OncologyLive: What are your views on the management of DCIS? Liotta: Some oncologists have said that we shouldn’t even use the word “carcinoma” to describe ductal carcinoma in situ because it’s wrong, it’s too scary, and these are low-risk lesions. But our experimental studies absolutely show that indeed there can be carcinoma cells lurking in those lesions. We found genetically altered cells that look the same as the genetic alterations in invasive cancer cells lurking in human DCIS lesions.

It’s very important for clinicians to understand that a DCIS lesion is not a benign lesion that should be left alone. Something should be done about it because we know that there could be carcinoma cells lurking in there waiting to be unleashed.

We see in our clinical trials that the women who have DCIS seem to be much more eager to get their lesion surgically removed and treated than even the physicians who are used to seeing a very bad outcome with invasive cancer. To the patient, it is just as significant as invasive cancer, and I would say the patient’s concern should be respected.

Please explain the goals of your approach to DCIS.

Our approach is to try to kill the DCIS lesion, kill the premalignant lesion, with one short-term therapy. It’s a new concept in prevention. Imagine a woman coming in to her doctor, getting a short-term therapy with something that’s not very toxic, or not toxic at all, and it kills the premalignant lesions lurking in the breast that we know are to become cancerous. That treatment will clean out all of the potential cancer that could develop in the future for that woman. You might administer this therapy once a year, once every couple of years, or perhaps only once in a woman’s lifetime.

How is this a different concept in prevention?

Standardized prevention trials will require five to 10 years to find out whether your vitamin therapy or your hormonal therapy is going to prevent cancer in that population. By then, science will have changed tremendously and there might be much better strategies with which to treat the patient. We can’t really wait that long to see the result of a prevention trial. We would like to have a trial where we’re treating premalignant lesions.

How is the chloroquine trial structured?

We want to take advantage of the time period between the diagnosis, the biopsy of the original DCIS lesion, and surgery. A woman is told that she has DCIS, that she has a premalignant lesion. She would enroll in our trial, and take chloroquine for 30 days, and then receive the standard-of-care surgical removal of the lesion that she would receive anyway. (Figures 1, 2)

There is usually a waiting period between the diagnosis and surgery. The patient is simply taking an oral medication during the waiting period, and then we can compare the lesion before she gets the drug, and after she has been on the drug, at the time of surgery. By comparing the DCIS lesion before and after therapy in the same patient, we will know if the therapy kills DCIS premalignant lesions or not. A positive result will strongly support the value of chloroquine as a potential short-term prevention therapy.

Figure 1. PINC Trial: Preventing Invasive Breast Neoplasia with Chloroquine

Identify patients, screen for eligibility, obtain consent

For patients with diagnosis of DCIS: Image-guided core biopsy for baseline biomarker analysis, breast MRI

DCIS

ER+

any grade

DCIS

ER-

any grade

Randomize

patients to

chloroquine

500 mg/wk or

250 mg/wk

x4 wks

Randomize

patients to

chloroquine

500 mg/wk or

250 mg/wk

x4 wks

Follow-up MRI, surgery, pathology for biomarkers; Radiation for lumpectomy patients; Clinical follow-up

DCIS indicates ductal carcinoma in situ; ER+, estrogen receptor-positive;

ER-, estrogen receptor-negative; MRI, magnetic resonance imaging.

How did your theory unfold?

Our first question in our experimental studies was: Do these invasive carcinoma cells really exist in the premalignant lesions waiting to emerge? Are there “terrorist” cells waiting to launch an attack? We had a DOD BCRP-sponsored clinical trial where we took living DCIS tissue from patients who volunteered to give their lesions to us at surgery, and we grew them with a new method and put them into animals. Seventy percent were able to produce tumors. They were genetically abnormal, similar to what we know the genetic abnormalities are of invasive cancer.

Our conclusion, based on experimental studies, was that the genetic changes that make a cell cancerous occur early—right in the premalignant lesion—and the cells are waiting in there to emerge and invade. Something is holding them back, maybe the microenvironment, but they are already there, and they exist much earlier than we thought.

What were the next questions in your investigations?

We recognized the stressful environment inside of the milk duct of the woman where the cells are proliferating to form atypical ductal hyperplasia or ductal carcinoma in situ. The neoplastic cells are crowding and building up inside those ducts. There are no blood vessels inside the ducts, so they have limited oxygen. There are very few nutrients. Nevertheless, they proliferate. Usually under high stress, many tissues or cells shut down and go into hibernation. But instead, in the DCIS lesions, when we look at proliferation markers, the cells are growing even though they’re under a high-stress environment.

Based on Ginny Espina’s experiments, we hypothesized that they use autophagy to survive. Autophagy is a pathway that’s a hot topic in science these days but has never been applied before to DCIS or premalignant breast lesions.

Figure 2. Treatment of Preinvasive Breast Lesions

Lance A. Liotta, MD, PhD, is focusing his research on ways to kill intraductal neoplastic cells before they become invasive.

Presented at 29th Annual Miami Breast Cancer Conference. March 15, 2012.

What is the role of autophagy in normal cells?

Autophagy is a special mechanism that’s very primordial. When cells are under high stress, they start eating internal parts of the cell and digesting the meals in the lysosomal compartment. The proteins that are digested in the compartment are transformed into ATP [adenosine triphosphate] energy for the cells.

Autophagy is a way for the cell to store up some energy and fill up its cookie jar, so to speak, when it’s hungry. When cells are under physical or chemical stress, or when they’re under starvation conditions, autophagy is switched on so that the cells can get alternative sources of energy. Autophagy is also used in the central nervous system to get rid of proteins that accumulate and to clean up misfolded proteins. In addition, autophagy is used in the immune system when a cell is making too much immunoglobulin, as in myeloma cells, for example.

So it’s a vacuum cleaner system, and a selfeating process. It allows a cell to get energy during emergency conditions. Autophagy is tightly regulated. It’s turned on when needed. But then when the cell is satiated, autophagy is turned off, and the cell goes back into a resting state.

How does autophagy function in cancerous cells?

The same way that it functions in normal cells. It is a way for cancerous cells to survive in the face of stress. We don’t know whether part of being a cancer cell is to turn on autophagy when it shouldn’t be on, but we certainly know that the cancer cell is using it to stay alive.

We see the autophagy being switched on just at the time that the cell is under stress inside the duct or when it’s under stress because it has just been treated with tamoxifen or anti-HER2 therapy. It allows the cell to deviate. Instead of going into apoptosis, instead of going into cell death, the cell prevents itself from dying by going into autophagy and staying alive.

How can autophagy be used as a therapeutic target?

When autophagy was first discovered in cancer, it was believed to be a different kind of apoptosis, a different way for the cell to die. The thought was, let’s just figure out how we can stimulate autophagy to make the cell eat itself to death as a treatment modality. But cells are much smarter than we think—normal cells and cancer cells. They’ll use autophagy to survive, but if it starts hurting them too much, they’ll stop doing it.

We think the better approach would be to use autophagy as a therapeutic target to block the process, at least for a short period of time during the premalignant period.

How can autophagy be used as a therapeutic target?

Autophagy is a complicated, multistep process. Proteins inside the cell are targeted for degradation; it does not seem to be just random. A double-walled membrane is formed around those proteins that are going to be metabolized, and then that membrane carries the proteins to a lysosome, which is already waiting with digestive enzymes inside of it. The proteins are degraded, and the output of that is then released for the mitochondria to make ATP and energy.

Chloroquine blocks the ability of that encapsulated protein from fusing with the lysosome and getting digested. The whole autophagy process becomes constipated. Chloroquine rapidly enters cells and blocks their lysosomes from working by changing the pH inside the lysosome.

What is the adverse-event profile of chloroquine?

The side effects are very low. We use oral slow-release chloroquine (Aralen; Sanofi) so the patients only have to take it once a week. It is immediately absorbed into the cells of the body. A low percentage of side effects has been seen in the multiple thousands of individuals treated with chloroquine in the past, including nausea and headaches. For some preparations of chloroquine, patients have very rarely reported blurry vision. We don’t know if that same effect is seen with Aralen; our patients are screened by an ophthalmologist and followed.

In addition, the reported side effects in past studies are experienced by patients who have been on long-term therapy with chloroquine. For the short 30 days that we’re administering it to the patients, the likelihood that there would be side effects is very low.

Are there implications for chloroquine research in tumor types other than breast cancer?

Yes, others have proposed the use of chloroquine to treat frankly malignant cancers. This includes pancreatic cancer, glioblastoma, and melanoma. There has been a study in animals to show that chloroquine prevents progression of lymphoma—all for the same reasons that we propose, that it prevents the cells of genetic damage from surviving and going on to become cancerous, or it prevents the cells from being resistant to therapy.