Tuya Pal, MD
H. Lee Moffitt Cancer Center & Research Institute, Inc.
“Prognosis and Outcomes of Women with PALB2-Associated Breast Cancer Etiology (PROMISE): A Pilot Study”

Recently, the PALB2 gene has been shown to be the third most important gene for inherited breast cancer, following the well known BRCA genes, BRCA1 and BRCA2. Genetic testing for alterations in PALB2 have become more common as testing costs have dropped due to scientific progress. This has led to more women receiving testing for PALB2 and other inherited cancer genes at the same time they are tested for the BRCA genes. As a result, more women are starting to discover that they have a mutation in PALB2, even though we are not yet sure how best to advise and treat them. Recent studies have confirmed that the risk of breast cancer in women with PALB2 mutations is similar to breast cancer risks in women with BRCA2 mutations. What is even more concerning is that early studies suggest that women with PALB2 mutations who develop breast cancer tend to be diagnosed with more aggressive disease which may lead to poorer outcomes. However until additional studies on larger numbers of women with PALB2 are done, it is not possible to come up with management and treatment guidelines for these women based on proven information. Through this pilot study, we will enroll 250 women with a mutation in PALB2 and breast cancer to learn more about what types of breast cancers they develop. This will also allow us to start building the groundwork for a larger PALB2 study, to follow-up on these women and figure out how they may be best treated to help them lead longer and healthier lives. We already submitted a larger grant to the Department of Defense breast cancer program, which was reviewed favorably but not funded. This pilot study will make our next grant submission stronger by showing the reviewers we have successfully built the single largest research study of PALB2 carriers in the world, to describe the types of breast cancers these women develop. But even more importantly, our study will set us up to follow these women to study their future cancer risks, outcomes, and best treatment options. Because PALB2 testing has only become widely available recently, large studies of breast cancers have not yet been done in this group of individuals. As such, this is a topic that has been studied very little, yet very important among those with breast cancer. Furthermore, the types of studies encouraged by the Florida Breast Cancer Foundation are those related to prevention, susceptibility, protection, recurrence and metastasis, all of which touch upon our long-term goals among PALB2 carriers. Specifically, our long-term goals are to end breast cancer, or greatly lower its impact, in women with PALB2 mutations through determining approaches which: 1) lower cancer risks, 2) prevent cancers all together, 3) detect cancers earlier, and 4) refine cancer treatments, all of which may substantially lead to improving the lives of women with PALB2 mutations and their close family members.


Masanobu Komatsu, PhD
Sanford Burnham Presbyterian Medical Discovery Institute
“MicroRNA control of Vascular Integrity in Breast Cancer”

An important characteristic of malignant tumors is the low oxygen environment of their interior.  In developing breast cancer, high metabolic demand of growing tumor cells overconsumes oxygen in the tumor tissues creating very hypoxic (low oxygen) environment. Tumors then stimulate formation of new blood vessels – the prcess called angiogenesis – to supply more blood to the tumors.  However, unlike blood vessels in healthy tissues, the new vessels formed in tumors are quite abnormal and defective, and they cannot adequately support blood flow to supply more oxygen to the tumors.  This create chronically hypoxic environment in tumors.

One would imagine that the lack of enough oxygen slows down the tumor growth, and hence it is a good thing for cancer patients.  However, hypoxia is actually one of the major reasons why breast cancer and many other types of cancers become metastatic and lethal.  Despite the unhospitable environment of low oxygen, many breast cancer cells survive and grow.  It is now well understood that hypoxia potentiates the ability of the tumor cells for local and metastatic dissemination via multiple mechanisms that modify activities of the tumor cells.  Hypoxia also weakens the immune system substantially reducing the ability of patient’s own defense mechanisms to kill tumor cells.  Furthermore, hypoxia significantly reduces the effectiveness of radiation therapy since oxygen is an important sensitizer for this treatment.  The recent progress in cancer research, therefore, highlights the previously unexpected benefit of oxygenating tumors in order to suppress metastasis, potentiate anti-tumor immunity, and enhance cancer treatment.

It will be a significant impact to our war against breast cancer if one can develop a therapeutic strategy to oxygenate tumors.  Our laboratory is aiming to do so by improving the blood vessel function in tumors.  Through the improvement of vessel functionality, normalization of tumor blood vessel network (tumor vasculature) could provide a novel therapeutic opportunity to oxygenate the tumors, and through this effect, diminish hypoxia-induced tumor metastasis, enhance immunity against cancer cells, and sensitize the tumors to radiation therapy.  Furthermore, normalization of tumor vasculature enhances drug delivery to the tumors thereby enhancing the efficacy of the drug therapy.  This provocative idea of tumor blood vessel normalization is supported by emerging preclinical evidence.  Finding a safe and effective strategy for vessel normalization will be a major breakthrough.

A type of RNA microRNA has been known to regulate gene expression.  microRNAs are involved in many physiological and pathological processes.  In the proposed study, we will explore the ability of microRNAs to control normalization of tumor vasculature and aims to understand the molecular mechanisms underlying this control.  This study has a potential to yield new avenues of investigation and accelerate the progress in designing better approach to oxygenating tumors.  These microRNAs or their target molecular pathways may be exploited to control tumor metastasis and the efficacy of anti-tumor therapies.  The proposed study will identify thee microRNAs.


Shuang Huang, PhD
University of Florida
“Deterring Breast Cancer Metastasis by Restoring miRNA Processing”

Breast cancer is one of the moat common malignancies among woman. Although early-staged and localized breast cancers can be cured by surgery and following treatment to eliminate remaining tumor cells, advanced metastatic breaat cancer are resistant to hormone therapy and respond poorly to chemotherapy and other targeted therapies. In fact, almost all breast cancer mortalities are the results of metastasis. Therefore, effective therapeutic modality against metastatic breast cancer is urgently needed. MicroRNAs (miRNAs) are small non-coding RNAa of —22 nucleotides that function as negative regulators of gene espression. MiRNAs are generated in a two-step process: 1) primary form to precursor form; and 2) precursor form to mature form. Estensive studies done in past decade have identified many miRNAs that can regulate breast cancer progression and metastasis. Interestingly, these studies also revealed that there are overwhelming more number of miRNAs acting as metastasis suppressors than those identified as promoters. Findings from these studies are actually consistent with the observation that global levels of miRNAs are reduced in aggressive tumors. In order to delineate the cause of reduced miRNA espression in metastatic breast cancer cells, we demonstrated that the process to generate mature miRNAs from primary forms is actually impaired in metastatic breast cancer cells. We further discovered that a molecule called protein kinase Cq (PKCq) is a molecule functioning to block the process that converts primary to mature miRNAs. Our findings led us to hypothesize that a novel therapeutic modality against metastatic breast cancer can be developed by restoring efficient production of miRNAs in metastatic breast cancer cells. Toward this goal, we have generated an inhibitor that can selectively block PKCq activity. We found that this inhibitor was able to significantly augment the production of metastasis-suppressive miRNAs in metastatic breast cancer cells. Our preliminary study has laid a solid foundation to teat the potential to treat metastatic breast cancer by reestablishing efficient miRNA processing through the inhibition of PKCq activity. The ultimate goal of this proposal is to use our newly developed PKC inhibitor as a therapeutic agent to treat metastatic breast cancer. We will accomplish our goal by two aims: 1) understanding how PKcq interferes with efficient miRNA production in metastatic breast cancer cells and 2) testing the efficacy of PKcq inhibitor to suppress breast tumor progression and metastasis in a well-established breast tumor pre-clinical model. The success of this application will provide proof-of concept on a novel therapeutic modality to treat metastatic breast cancer.


Dorraya El-Ashry, PhD
University of Miami, Miller School of Medicine
“Cancer associated Fibroblasts Communicate via secreted miRNAs to drive Breast cancer Progression”

Metastasis is the main cause of breast cancer mortality, and non-cancer cells that surround tumor cells play pivotal roles in facilitating breast cancer metastasis. Tumor cells interact with non-cancer cells to establish a tumor microenvironment (TME), wherein the non-cancer cells are referred to as stromal cells. In breast cancer, the stromal cells of the TME are mostly cells called Cancer Associated Fibroblasts (CAFs), cells that have many cancer promoting properties and activities that are involved in cancer progression and metastasis. CAFs can cause activation of a procancer signaling pathway in breast cancer cells, the ERK1/2 MAPK pathway, which facilitates cancer cell survival, proliferation, and aggressiveness, and is associated with poor outcomes in breast cancer patients. We have recently identified a signature of small regulatory RNAs, called microRNAs, associated with hyperactivation of MAPK signaling. MicroRNAs are small non-coding RNAs that act as master regulators of gene expression and protein expression. We demonstrated that this hMAPK-microRNA signature is prognostic of poor clinical outcomes in breast cancer patients. Furthermore, breast cancers with this hMAPK-microRNA signature have significantly higher stromal cell infiltrates, suggesting that non-tumor cells in the TME contribute to this microRNA signature. We propose that stromal cells may critically facilitate the poor clinical outcomes associated with the hMAPK-microRNA signature. To study the contribution of CAFs to breast cancer progression and metastasis, we established ‘aggressive’ and ‘indolent’ CAF cell lines from specific types of breast cancer (Basal/HER2, and Luminal A, respectively). These CAFs exhibit differential expression of several hMAPK-microRNAs compared to breast cancer cells, and microRNAs secreted by ‘aggressive’ CAFs carry out tumor-promoting actions of hMAPK that are lacking from ‘indolent’ CAFs.

These data suggest that there exist different CAF populations with distinct abilities to influence the phenotype and behavior of the breast cancer cells they associate with. The proposed research is an innovative idea and fits in the Scientific Research Grant Theme of basic, clinical, and translational breast cancer research. We propose to define the contribution of microRNAs to the 'indolent' or 'aggressive' behavior of CAFs, with particular interest on hMAPK-microRNAs, and we aim to establish a hierarchy of CAFs derived from different primary breast tumor subtypes in regards to their potential to promote breast cancer metastasis. As a pilot study, we will further identify a profile of microRNAs that are present in the circulation of patients with breast cancer, or in animal models representing breast cancer with different metastatic potential, to explore possible connections between microRNAs secreted by CAFs and severity of disease progression/metastasis. We anticipate identifying novel tumor/CAF interactions in breast cancer that facilitate MAPK actions essential to tumor progression, metastasis, and poor outcome, and define a novel role for MAPK-microRNAs in governing these processes. This will have an important impact by elucidating mechanisms underlying breast cancer metastasis, and may provide novel means to distinguish aggressive from indolent disease. These CAF-secreted hMAPK-microRNAs may be biomarkers and drivers of aggressive, poor prognosis breast cancer, which may ultimately represent new therapeutic targets in the treatment or prevention of breast cancer metastasis.


Joyce M. Slingerland, MD, PhD
University of Miami, Miller School of Medicine-Sylvester Comprehensive Cancer Center
“Mechanistic Links between changing Estrogen Profiles, Inflammation and the Increased Risk and Metastasis of Breast Cancer in Obese Women”

Despite recent advances, breast cancer is the leading cause of cancer death in women and risk thereof rises after menopause.  Here we address the increased risk and worse outcome of breast cancers arising in obese postmenopausal women.  About two thirds of breast cancers express the estrogen receptor and are stimulated by estrogen.  Obesity, which is on the rise, increases the risk of postmenopausal estrogen receptor-positive (ER+) cancers.  There are two main female estrogens: estradiol and estrone.  Before menopause estradiol is high and estrone contributes only one third of the circulating estrogen.  Postmenopausal women have much lower estradiol, and estrone becomes the major circulating estrogen.  After menopause, estrogens are produced mostly in fat tissue.  Estrogen levels are higher in obese than normal body weight women because fat tissue is the place where pre-estrogen hormones get converted to estrogens.  The major estrogen produced in the fat after menopause is estrone.  Obesity and higher levels of estrone both correlate with increased risk of developing ER+ breast cancer in postmenopausal women.  Our grant investigates how increased estrone after menopause or a higher ratio of estrone to estradiol may contribute to breast cancer development and the worse outcome in obese postmenopausal women.

Obese fat tissue (called adipose tissue) causes chronic inflammation that may contribute to breast cancer development and progression.  We recently showed that as breast cancers invade fat tissue, their contact with fat cells increases proteins that drive inflammation, and stimulate growth of the most aggressive cancer cells, called stem cells, that resist treatment and initiate cancer spread to other organs.  Although estradiol has been shown to have an anti-inflammatory effect, our work shows that postmenopausal estrone may activate inflammation.  Notably, breast cancer risk increases after menopause, when estradiol levels go down dramatically and estrone increases, particularly with weight gain.  We plan to test if the increased estrone:estradiol ratio after menopause contributes to the chronic inflammation in breast and abdominal fat in obesity.  We will test if the switch from estradiol to estrone stimulates both obesity related inflammation and breast cancer stem cells.  This work may provide new insights as to how estrogens increased risk and poor outcome of ER+ breast cancer in obese women.

This work may clarify how different estrogens impact breast cancer risk and reveal molecular pathways that explain the link between obesity, increased estrone and postmenopausal breast cancer.  Findings generated may lead to a great understanding of how estradiol may protect against neurodegenerative disease, Alzheimer’s, and heart disease and indeed play a protective role against breast cancer and reveal risks associated with estrone, the dominant physiologic estrogen after menopause.

This work has implications for women’s health maintenance and breast cancer prevention.  The major drug used for post-menopausal hormone replacement therapy, premarin, contains estrone and may not be the safest estrogen therapy.  This work may lead to design of better postmenopausal hormone replacement therapies, identify new markers for breast cancer risk and/or outcome, and the discovery of novel therapeutic targets for more effective drugs for breast cancer prevention and cure.



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