MASSACHUSETTS GENERAL HOSPITAL, THE
Mutations in the NF2 tumor suppressor gene underlie Neurofibromatosis type 2 (NF2), a familial cancer syndrome featuring the development of central nervous system tumors. The NF2-encoded protein, Merlin, is closely related to the ERM (Ezrin, Radixin and Moesin) proteins, which are thought to facilitate the assembly of membrane:actin cytoskeleton complexes. However, the mechanism whereby Merlin controls cell proliferation is not known. To create an animal model for Nf2-associated tumorigenesis and develop tools for defining the molecular function of Merlin, we generated an Nf2-mutant strain of mice and found that Nf2 mutation predisposes mice to a variety of highly metastatic cancers. This is surprising given the limited spectrum of benign tumors in human NF2 patients and suggests that Nf2 inactivation may play an unrecognized role in cancer development and progression. Our broad objective is to use Nf2-mutant mice and cells to delineate the function of Merlin and its family members in cancer development and progression. We have recently found that a signature of Nf2-deficiency across several types of primary cells is loss of contact-dependent inhibition of proliferation and lack of normal cadherin-mediated cell:cell communication. We discovered that Merlin localizes to cadherin-containing adherens junctions (AJs) in wild-type cells and is required for the establishment of the final actin cytoskeleton associated AJ structure. We also found that silencing of the epidermal growth factor receptor (EGFR) at high cell density, which is known to be mediated by AJ establishment, is defective in the absence of Merlin. The goals of this proposal are to determine whether control of AJ establishment and EGFR silencing is the cellular mechanism whereby Merlin acts as a tumor and metastasis suppressor and to delineate the mechanism of Merlin function in AJ establishment. The results of this study will yield important insight into the mechanism of Merlin function as a tumor suppressor and identify novel targets for therapeutic intervention of NF2.
| AWARD OVERVIEW |
| Award Number |
3R01CA113733-05S1 |
Funding Agency |
Department of Health and Human Services |
| Total Award Amount |
$125,662 |
Project Location - City |
Boston |
| Award Date |
09/16/2009 |
Project Location - State |
MA |
| Project Status |
Completed |
Project Location - Zip |
02114-0000
|
| Jobs Reported |
0.00 |
Congressional District |
09 |
| Project Location - Country |
US |
|
|
Recipient Information
(Grants)
| Recipient Information (Grants) |
|
Recipient Name
|
MASSACHUSETTS GENERAL HOSPITAL, THE |
| Recipient DUNS Number |
073130411
|
| Recipient Address |
55 FRUIT ST |
| Recipient City |
BOSTON |
| Recipient State |
Massachusetts |
| Recipient Zip |
02114-2621 |
| Recipient Congressional District |
09 |
| Recipient Country |
USA |
Required to Report Top 5
Highly Compensated Officials |
No |
Projects and Jobs Information
| Projects and Jobs Information |
| Project Title |
Molecular Function of the Nf2 Tumor Suppressor, Merlin |
| Project Status |
Completed |
| Final Project Report Submitted |
Yes |
| Project Activities Description |
General Medical and Surgical Hospitals |
| Quarterly Activities/Project Description |
The goals of this supplement are to: 1) Use new technology (single particle tracking microscopy; SPTM) to delineate the molecular mechanism whereby the NF2 tumor suppressor, Merlin controls the membrane distribution of and signaling from the EGFR and 2) Determine whether persistent EGFR signaling is responsible for the phenotypic consequences of Nf2-deficiency in mice in vivo. During the first quarter we used SPTM to confirm that Merlin immobilizes ligand-activated EGFR in confluent cells. We also found that Merlin dictates whether EGFR undergoes clathrin-dependent (CME) or –independent (NCE) endocytosis prior to confluence by limiting its distribution to sterol-rich membranes (SRMs). This provides fundamental new molecular insight into receptor-mediated endocytosis. In the second quarter we found that Merlin promotes ligand-independent ubiquitination of receptors that enter SRMs, thereby limiting NCE in favor of CME. In the third quarter we found that Merlin-dependent EGFR pUb prior to confluence is dependent on the PDZ-domain containing adapter NHE-RF1, which can link Merlin to EGFR. In the fourth quarter we found that inhibition of EGFR blocks Merlin-dependent EGFR immobilization at confluence via feedback. During this time we found that Merlin can directly interact with alpha-catenin, a known component of the adherens junction. Since recent studies suggest cell junction-independent roles for alpha-catenin in regulating the cortical actin cytoskeleton, we hypothesize that Merlin immobilizes EGFR via alpha-catenin. Indeed, in the final month of this award we learned two new things that strongly support this idea: First, knockdown of alpha-catenin diminishes Merlin localization to both AJs and to the cortical cytoskeleton. Second, a mutant version of Merlin that can neither decorate the cytoskeleton nor associate with alpha-catenin can promote EGFR pUB and CME but cannot block EGFR endocytosis at confluence. We are currently testing the hypothesis that Merlin acts |
| Jobs Created |
0.00 |
| Description of Jobs Created |
This award allowed me to retain a senior postdoctoral fellow and hire an undergraduate student (3 months) to expand the scope of experiments described in the parent grant. The parent grant is in its final year of funding and I prepared and submitted a competitive renewal on Nov. 5, 2009 that was funded for five years at first submission; preliminary data from these ARRA funded experiments were a centerpiece of the competitive renewal. This work also formed the basis of a revised manuscript that we will resubmit jointly to Cell/Developmental Cell. This work will advance our understanding of the molecular basis of several types of cancer and provide insight into the response of certain types of cancer to available targeted therapies. |
Purchaser Information
(Grants)
| Purchaser Information |
| Contracting Office ID |
Not Reported |
| Contracting Office Name |
Not Available |
| Contracting Office Region |
Not Available |
| TAS Major Program |
75-0850 |
| Award Information |
| Award Date |
09/16/2009 |
| Award Number |
3R01CA113733-05S1 |
| Order Number |
|
| Award Type |
Grants |
| Funding Agency ID |
75 |
| Funding Agency Name |
Department of Health and Human Services |
| Funding Office Name |
Not Available |
| Awarding Agency ID |
75 |
| Awarding Agency Name |
Department of Health and Human Services |
| Amount of Award |
$125,662 |
| Funds Invoiced/Received |
$125,662 |
| Expenditure Amount |
$125,662 |
| Infrastructure Expenditure Amount |
$0 |
| Infrastructure Purpose and Rationale |
Not Reported |
| Infrastructure Point of Contact Name |
Not Reported |
| Infrastructure Point of Contact Email |
Not Reported |
| Infrastructure Point of Contact Phone |
Not Reported |
| Infrastructure Point of Contact Address |
Not Reported |
| Infrastructure Point of Contact City |
Not Reported |
| Infrastructure Point of Contact State |
Not Reported |
| Infrastructure Point of Contact Zip |
Not Reported |
Product or Service Information
(Grants)
| Product or Service Information |
| Primary Activity Code |
622110 |
| Activity Description |
General Medical and Surgical Hospitals |
| Sub-Awards Information |
| Sub-awards to Organizations |
0 |
| Sub-award Amounts to Organizations |
$0 |
| Sub-Awards to Individuals |
0 |
| Sub-Award Amounts to Individuals |
$0 |
| Number of Sub-awards less than $25,000/award |
0 |
| Amount of Sub-awards less than $25,000/award |
$0 |
| Number of payments to vendors greater than $25,000 |
0 |
| Total Amount of payments to vendors greater than $25,000/award |
$0 |
| Number of payments to vendors less than $25,000/award |
131 |
| Total Amount of payments to vendors less than $25,000/award |
$25,011 |
| Location Information |
| Latitude, Longitude |
42º 21' 44",
-71º 4' 11" |
| Congressional District |
09 |
| Address 1 |
55 Fruit Street |
| Address 2 |
|
| City |
Boston |
| County |
Suffolk |
| State |
MA |
| Zip |
02114-0000 |
|
 |