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Research at Mass General
Field cancerization is a condition of major clinical significance consisting of multifocal and recurrent tumors with widespread changes (cancer fields) of surrounding normal tissues. It is associated with development of all common epithelial cancer types, with frequency of multiple primary lesions ranging between 3 and 90%, depending on target organs and triggering events. This process has also been linked to development of brain tumours, myelodysplastic syndromes and melanomas.
The main research efforts of our laboratory are focused on the concerted changes of epithelial and stromal cells that underlie field cancerization, utilizing skin as primary experimental system. Clinical relevance of the results is assessed by analysis of premalignant and malignant lesions of skin, head/neck and lung SCCs (squamous cell carcinomas) and breast cancer.
On the basis of the bad seed / bad soil hypothesis illustrated below, two main topics are being addressed : (i) intrinsic control mechanisms underlying the opposing balance between epithelial cell differentiation and cancer; (ii) role of underlying mesenchymal cells in control of epithelial tumorigenesis.
For representative publications and more detailed description, see below. For a more general interview article see "A balance of signals":PDF of interview article
Environmental insults, like UV irradiation or smoke, can target both epithelial and stromal compartments of organs such as skin, head/neck, lung, bladder or breast, with ensuing genetic and/or epigenetic changes. Establishment and spreading of “cancer fields” is the likely result of an interplay between epithelial and stromal alterations, with the latter playing an equally important and possibly primary role. The situation leading to multifocal and recurrent epithelial cancer may be analogous to that of a bad plant difficult to eradicate. This may be due to roots deeply embedded in the terrain or the spreading of bad multiple seeds, growing in the presence of a permissive or favorable soil.
An alternative possibility with important conceptual implications is that the main problem is the soil itself. A bad soil could corrupt properties of otherwise perfectly good plants or seeds. According to this view, unless the soil is corrected, various forms of prevention and intervention would be of little or no use.
i) Multifactorial control of squamous cell differentiation and cancer.
Squamous cell carcinomas (SCCs) are the most common form of human solid tumors in aggregate and a major cause of cancer mortality. These highly heterogeneous tumors arise from closely interconnected epithelial cell populations with intrinsic self-renewal potential inversely related to the stratified differentiation program. Keratinocytes and skin provide an attractive experimental system to study the connection between squamous cell differentiation and cancer. Notch signalling is an important form of cell-cell communication with a function that is highly context-dependent.
A substantial body of evidence (reviewed in 1) has confirmed and expanded our original findings that this pathway plays a key role in promoting epidermal cell differentiation and suppressing tumor development 2-3.
We showed that the Notch1 gene, which plays the most critical function in keratinocytes, is a direct target of p53 and that down-modulation of Notch1 expression in keratinocyte-derived tumors can be explained by mutation of p53 4 or down-modulation of p53 expression by increased EGFR activation 5 or calcineurin inhibition 6.
Notch activation, in turn, suppresses p63, a p53-related transcription factor with an essential role in maintenance of keratinocyte self renewing populations 7. Importantly, deep sequencing analysis of head/neck, skin and lung squamous cell carcinomas (SCCs) by a number of other laboratories has revealed that one or more components of the Notch/p53/p63 network can be inactivated by mutations in human SCCs, confirming their key role in the disease 8-11.
The cross-talk between Notch, p53/EGFR and p63 is at the core of a genetic network with a key role in keratinocyte growth/differentiation control and tumor development 12.. Other components of this network are IRF6, a transcription factor of the IRF (Interferon Responsive Factors) family that we have recently established as Notch target 13, and miR34a, a microRNA with a key p53 effector function that we have shown to control squamous cell differentiation through the targeting of the histone deacetylase Sirt6 14.
We have further found that estrogen receptor ß (ER-ß) is an important direct regulator of Notch1 expression and function, and increased ER-ß signalling induces differentiation of cells derived from skin-, head/neck-and lung SCCs 15. The findings point to the possible use of ER-ß selective agonists for prevention and treatment of these tumours. Additionally, they provide a basis for further studies on the substantially different susceptibility to SCC development between male and female individuals.
Summary diagram of the Notch-connected network involved in keratinocyte differentiation and tumor suppression.
A set of representative genes with a known or likely role in keratinocyte differentiation and Notch signalling is indicated. For explanation and more complete specification of network elements and connections, see the text above and cited reference.
ii) Field cancerization : stroma as a primary determinant.
While great attention has been paid to the role of Notch signalling in keratinocytes and SCC cells, we have started to explore the role of this pathway in the underlying mesenchyme. We have developed a genetic mouse model with loss of Notch signalling in the mesenchymal compartment of the skin, finding that this pathway is essential for cell fate maintenance of overlying hair follicle keratinocytes 16. More importantly, by combined analysis of the mouse model and clinically-derived skin samples, we have uncovered a novel essential role of mesenchymal Notch signalling in field cancerization in the skin17.
Field cancerization has been linked to the presence of genetic pro-tumorigenic changes in apparently normal ‘patches’ of epithelial cells that expand over time 18.. Our recent findings indicate that compromised Notch signalling in the underlying dermal fibroblasts is likely to play an equally important primary role, resulting in tissue alterations (stromal atrophy and inflammation) that precede premalignant and malignant epithelial tumor development 17. Mechanistically, Notch signaling in dermal fibroblasts of both murine and human origin results in intrinsically increased expression of diffusible growth factors and inflammatory cytokines, cancer-associated matrix components and matrix remodeling enzymes, which are amenable to up-regulation of AP1 levels and activity 17.
The findings are of likely clinical significance, as suppression of Notch/CSL signaling and associated gene expression events occur in stromal fields adjacent to cutaneous premalignant lesions (actinic keratosis), and can be induced by UVA exposure, a major cause of skin aging and cancer-predisposing alterations17.
We have established an intensive research effort to further explore the molecular and cellular basis of field cancerization in the skin and other organs, and assess the translational implications for prevention and treatment of epithelial cancer 19.
Summary diagram of the Notch/CSL-connected network involved in dermal fibroblast activation and skin field cancerization.
The genes in the network are partially overlapping with those involved in the keratinocyte network illustrated above. The diagram is based on our recent findings that UVA exposure of human skin / dermal fibroblasts induces down-modulation of Notch expression and activity through specific mechanisms like increased DNA methylation of the Notch2 promoter 17. Notch suppression leads to up-regulated expression of AP1 family members and of AP1 target genes with a role in activation of Cancer Associated Fibroblasts (CAFS) and subsequent inflammation and promotion of cancer development17.
PDF of Cited Publications
REPRESENTATIVE RECENT PUBLICATIONS
Goruppi, S. and Dotto, G.P. Mesenchymal stroma: primary determinant and therapeutic target for epithelial cancer. Trends Cell Biol. 2013; 23 : 593-602.
Bibliography Updated 2016
View my publications at Pub Med
Biography: Gian-Paolo Dotto, MD, PhD
Dr. Dotto received his MD from the University of Turin, Italy, in 1979, and his PhD in Genetics from the Rockefeller University, New York, in 1983. After postdoctoral training with Robert A. Weinberg at the Whitehead Institute/MIT in Cambridge, Mass., in 1987 Dr. Dotto joined Yale University, New Haven, Connecticut, as assistant professor of Pathology. In 1992 he was promoted to the rank of associate professor and soon after moved to Harvard Medical School, as associate professor of Dermatology in the newly established Cutaneous Biology Research Center. In 2000 he was promoted to the rank of Professor at Harvard Medical School and Biologist at Massachusetts General Hospital. In 2002 he accepted a position of Professor in the Department of Biochemistry at the University of Lausanne, while retaining his position of Biologist at Massachusetts General Hospital. He has been elected to the European Molecular Biology Organization (2011), the Academia Europaea (2012) and the Leopoldina German National Academy of Sciences (2014). He is the recipient of a number of awards, including the American Skin Association Achievement Award (2012) and an ERC Advanced investigator grant award (2013).
Giulia Bottoni - email@example.com Seunghee Jo - firstname.lastname@example.orgSandro Goruppi - email@example.comAndrea Clocchiatti - firstname.lastname@example.org
Bibliography Updated 2016
View my publications at Pub Med
Cutaneous Biology Research Center
Directions to Charlestown Navy Yard MGH East - Building 149
From Storrow Drive
From the end of Storrow Drive (Leverett Circle) keep to the far right and take a sharp right (do not go up the ramp), and continue beneath the underpass one quarter mile to the light.
Turn left onto Causeway street under the elevated subway tracks. The Fleet Center will be on your left, the North Station T station on your right.
One block past the Garden, turn left on to N. Washington Street, passing over the Charlestown Bridge.
At the first light after the bridge, take a right. Go through three traffic control lights.
At the fourth light, turn right into Navy Yard (Gate 5 - 13th Street). To park, take first left onto Fifth Avenue. Building 149 is one block on the right.
The parking garage entrance is on the right about half way down the block.
Take the Mass Pike (I-90) to I-93 North (Exit 24B)
Take the Storrow Drive Exit (Exit 26)Stay in the left lane once getting on the exit ramp. Follow signs for North Station/Leverett Circle Go through 1 light and take left at the 2nd light (almost immediately after the first)
Get immediately into the right lane
Take a right at the light onto Route 28N
The Museum of Science will be on your left
Take a right at the 3rd light (there is a sign at the corner for Charlestown)
Go over the bridge and get in the right lane (City Square)
Take your 1st right and get into the left lane
Turn left at the 2nd light (immediately before Charlestown Bridge, at City Square) onto Chelsea Street (If you go over bridge, you've gone too far).
Go through three traffic control lights
At the 4th light, turn right into the Navy Yard (Gate 5 - 13th Street).
To park, take first left onto Fifth Avenue. Parking Garage entrance is on the right above half way down the block. Building 149 is one block on the right once you turn into Gate 5. Building 149 is also connected to the parking garage.
Take Exit 28 (Charlestown/Sullivan Square).
At the end of the exit where the read forks stay to the right and proceed past the bus terminal to the rotary at Sullivan Square.
Go halfway around the rotary towards Charlestown (the Schrafts building with a large American flag on top of it will be on your left).
Cross the railroad tracks and take a left at the fire station onto Medford Street.
At the end of Medford street turn left onto Chelsea Street and make an immediate right into the Navy Yard.
The MGH East Research Building (Bldg. 149) will be on the right and is connected to the parking garage by overhead walkways.
Direct the driver to the MGH East, Building 149 in the Charlestown Navy Yard.
The CBRC is on the 3rd Floor of Building 149.By Public Transportation & the MGH/Partners Shuttle
Take the T (Green Line) to North Station
Take the MGH/Partners Shuttle bus to the Charlestown Navy Yard MGH East Research Building (Building 149).
The CBRC is on the 3rd Floor.
The MGH/Partners Shuttle bus leaves MGH on Blossom Street and stops at North Station on Canal Street by the Green Line T stop. The shuttle goes every 15 minutes during working hours. (Less often on the weekends and holidays).
To get to the CBRC, take the first set of elevators to the left of the main entrance by the Security Desk to the third floor. You may need to check in with security on the main level of Building 149.
From the elevator, exit to the East to the CBRC offices, or in the opposite direction for the laboratories.
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