Scientists Find Potential Therapeutic Target for Cushing’s Disease

Scientists at the Salk Institute for Biological Studies have identified a protein that drives the formation of pituitary tumors in Cushing’s disease, a development that may give clinicians a therapeutic target to treat this potentially life-threatening disorder.

The protein, called TR4 (testicular orphan nuclear receptor 4), is one of the human body’s 48 nuclear receptors, a class of proteins found in cells that are responsible for sensing hormones and, in response, regulating the expression of specific genes. Using a genome scan, the Salk team discovered that TR4 regulates a gene that produces adrenocorticotropic hormone (ACTH), which is overproduced by pituitary tumors in Cushing’s disease (CD). The findings were published in the May 6, 2013 early online edition of Proceedings of the National Academy of Sciences.

The diagram shows how adrenocorticotropin hormone is secreted in Cushing's disease.

“We were surprised by the scan, as TR4 and ACTH were not known to be functionally linked,” says senior author Ronald M. Evans, a professor in Salk’s Gene Expression Laboratory and a lead researcher in the Institute’s Helmsley Center for Genomic Medicine. “TR4 is driving the growth and overexpression of ACTH. Targeting this pathway could therapeutically benefit treatment of CD.”

In their study, Evans and his colleagues discovered that forced overexpression of TR4 in both human and mouse cells increased production of ACTH, cellular proliferation and tumor invasion rates. All of these events were reversed when TR4 expression was reduced.

First described more than 80 years ago, Cushing’s disease is a rare disorder that is caused by pituitary tumors or excess growth of the pituitary gland located at the base of the brain. People with CD have too much ACTH, which stimulates the production and release of cortisol, a hormone that is normally produced during stressful situations.

While these pituitary tumors are almost always benign, they result in excess ACTH and cortisol secretion, which can result in various disabling symptoms, including diabetes, hypertension, osteoporosis, obesity and psychological disturbances. Surgical removal of the tumors is the first-line therapy, with remission rates of approximately 80 percent; however, the disease recurs in up to 25 percent of cases.

Drugs such as cabergoline, which is used to treat certain pituitary tumors, alone or in combination with ketoconazole, a drug normally used to treat fungal infections, have been shown to be effective in some patients with Cushing’s disease. More recently, mefipristone-best known as the abortion pill RU-486-was approved by the FDA to treat CD. Despite these advances in medical therapy, the Salk scientists say additional therapeutic approaches are needed for CD.

“Pituitary tumors are extremely difficult to control,” says Michael Downes, a senior staff scientist in the Gene Expression Laboratory and a co-author of the study. “To control them, you have to kill cells in the pituitary gland that are proliferating, which could prevent the production of a vital hormone.”

Previous studies have found that, by itself, TR4 is a natural target for other signaling molecules in the pituitary. Small-molecule inhibitors that have been developed for other cancers could be potentially applied to disrupt this signaling cascade. “Our discovery,” says Evans, a Howard Hughes Medical Institute investigator and holder of the March of Dimes Chair in Molecular and Developmental Biology, “might lead clinicians to an existing drug that could be used to treat Cushing’s disease.

Notes about this neurogenetics and Cushing’s disease research

Other researchers on the study were Li Du, Marvin Bergsneider, Leili Mirsadraei, Stephen H. Young, William H. Yong and Anthony P. Heaney of the David A. Geffen School of Medicine at the University of California, Los Angeles, and Johan W. Jonker of the University of Groningen.

The study was supported by the National Institutes of Health, the Leona M. and Harry B. Helmsley Charitable Trust, the Samuel Waxman Cancer Research Foundation, the Jonsson Comprehensive Cancer Center at UCLA, and Ipsen/Biomeasure.

Contact: Andy Hoang – Salk Institute
Source: Salk Institute press release
Image Source: The ACTH Cushing’s disease diagram is credited to NIDDK/NIH and is available in the public domain.
Original Research: Abstract for “Evidence for orphan nuclear receptor TR4 in the etiology of Cushing disease” by Li Du, Marvin Bergsneider, Leili Mirsadraei, Steven H. Young, Johan W. Jonker, Michael Downes, William H. Yong, Ronald M. Evans, and Anthony P. Heaney in Proceedings of the National Academy of Sciences. Published May 6 2013 doi: 10.1073/pnas.1306182110


Interview May 7 with Kathy C, Pituitary Patient

My name is Kathy Casey. I am a 63 year old retired school nurse. I am married with two wonderful sons and a grandson. My husband and I live in the mountain town of Mt. Shasta in northern California. I have always been athletic.

In 1995, I was diagnosed with a pituitary tumor. At the time the only symptom I was aware of was a severe headache. I had a transphenoidal resection by Dr. Wilson at UCSF Medical Center followed by radiation therapy for 23 days. At the time they said they could not remove all of the tumor.

In 2008/2009. I exhibited symptoms of Cushing’s and my cortisol level was outrageous, and I had to be hospitalized initially for a potassium level of 2. I returned to UCSF and Dr. Anwar Sandeep operated . By removing part of the tumor. My Cushing symptoms resolved. However, he said that the tumor was not encapsulated and was invading the cavernous sinus and stella turcica so it was still not possible to remove it all.

I was OK until December 2013 when I began exhibiting the symptoms of Cushings. One of my 24 hr. urines was 14,000. I had to be hospitalized for a potassium level of 1.9. Dr. Heaney said he has never seen a cortisol level that high. This time I decided to go to the UCLA Pituitary Tumor and Endocrinology Program where they were more oriented to follow-up and treating this disorder. Dr. Bergsneider decided that surgery was not an option. He and Dr. Heaney decided radiation was not an option. So now I am being followed by Dr. Heaney to see if medication can help.

I am now on Cabergoline 0.5 mg three tabs twice a week and Signifor 0.9 mg subcutaneosly twice a day. I think they are alleviating some of the symptoms. However, the Signifor caused my blood sugar to rise, and I had to go on Metformin which is causing nausea to a point where I have a hard time eating.

Anyway, this whole situation is depressing and overwhelming. I am tryng to stay positive, but I wonder how it will turn out. I am fortunate to have a supportive and helpful husband.

I am interested in communicating with people who may be going through a similar experience and learning more about this rare condition.

Kathy will be interviewed May 7, 2014 in BlogTalkRadio

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Notes on the Magic Foundation Cushing’s Conference, 2012

Here are links to all the posts in order, although some still need to be edited.  I posted these directly from the meeting hall with no rereads or rewrites.  If anyone has anything to add, edit or delete, please let me know!


  • Magic Conference: Understanding your Pituitary Gland in Health and Disease

Dr. Frohman will present an overview of the pituitary gland. He will cover general aspects of pituitary function and testing and also review the types of pituitary disease that occur, including pituitary tumors and Sheehan’s Syndrome. Many people ask and wonder if Growth Hormone Deficiency can be inherited. Dr. Frohman will also briefly address that concern.


  • Magic Conference: Testing and Diagnosis Process for Pituitary Disorders

Pituitary disorders can be difficult to diagnose in many cases. Dr. Salvatori will discuss the different testing and diagnostic procedures to determine the pituitary disorder. MAGIC receives many calls asking about diagnostic procedures. This segment will be helpful in understanding what procedures are used today to provide the best treatment available.


  • Magic Conference: Managing Medications and Aftercare of Treatments

It is crucial to monitor your treatments and aftercare of treatments when living with a pituitary disorder. Dr. Salvatori will discuss the importance of these issues so you will be aware of how to manage your pituitary disorder. A simple diagnosis does not mean that medications may be altered or changed in the future. This segment will assist you with information on how to manage your future.


  • Magic Conference: Cushing’s Disease, Are We Closer to Medical Therapies?

A significant proportion of patients with Cushing’s Disease are not cured by primary surgical treatment, the disease is prone to relapse and significantly damages quality of life. Adjuvant radiotherapy is an increasingly unattractive option for clinicians who wish to spare their patients hypopituitarism and other potential complications. Some pharmacological options are currently available but tend to have dose-limiting side effects. New agents recently approved or under investigation will be discussed and strategies to select the optimal drug or drug combination for individual patients reviewed.


  • The Trip So Far…

MaryO’s personal experiences and thoughts


  • Cushing’s Help Turned Twelve During the Conference!

Twelve  years ago I was talking with my dear friend Alice, who runs a wonderful menopause site, Power Surge, wondering why there weren’t many support groups online (OR off!) for Cushing’s and I wondered if I could start one myself.  We decided that I could.

This website ( first went “live” July 21, 2000 and the message boards September 30, 2000. Hopefully, with this site, I’ve made  some helpful differences in someone else’s life.


  • Magic Conference: Treating Cushing’s Disease with Surgery: Ways of Achieving a Cure

Dr. McCutcheon will discuss the ways of treating Cushing’s disease from the surgical perspective, including the different ways of getting to the pituitary, the chances of success, and the potential complications. In addition, special nuances and pitfalls ofsurgery in Cushing’s (as opposed to other types of pituitary tumor) will be addressed.


  • Phil and the Zebra Undies

Dr. McCutcheon is a surprise participant in a gift to Phil.


  • Real Talk: Psychological Process of Illness, part 1

This Segment will be broken into two sections. Part I will be provide an open opportunity for participants to ask relevant questions around the emotional/mental issues in living with a chronic illness. Participants will be able to openly talk about depression, anxiety, trauma, and other processes that occur when living illness.


Due to confidentiality issues, most of this segment is not shared.


  • Real Talk: Psychological Process of Illness, part 2

Part II will focus on seeing ourselves as survivors of illness and the process of staying empowered through illness that impacts us in such a powerful way. Principles of empowerment and how one can turn adversity into opportunity will be discussed. This segment should create an environment that is non judgmental and motivating.


Due to confidentiality issues, most of this segment is not shared.


  • The Rest Of The Trip

Wind-up and heading home

Eventually, all these posts will be edited, cleaned up and typos corrected.;

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