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Molecular Oncology Research Institute (MORI)

Hinds Laboratory

Philip W. Hinds, PhD, Principal Investigator, MORI at Tufts Medical CenterOur laboratory studies the role of the retinoblastoma protein (pRB) pathway in differentiation and cancer. The retinoblastoma protein acts to control proliferation at least in part by regulating transcription of genes required for DNA synthesis. Recent work demonstrates that pRB can also promote the synthesis of gene products involved in generating the differentiated phenotype of a number of different tissue types. Further, pRB plays a role in enforcing the permanent cell cycle withdrawal associated with terminal differentiation and the tumor-suppressive process of senescence.

G1 Cell Cycle Dysregulation in Cancer

The focus of my laboratory is on G1 cell cycle control and its dysregulation in cancer cells. Specifically, we are investigating the function of the retinoblastoma protein, (pRb), D-type cyclins, cdk4 and cdk6 in programs of cell cycle exit. Together, along with p16INK4a, a negative regulator of cdk4 and cdk6, these proteins regulate a critical decision making point in progression to S phase and thus DNA replication. In almost all human tumors, one of these proteins is lost or overexpressed, thus favoring proliferation and tumor growth. Although these proteins regulate S phase in response to genome integrity (DNA damage), we and others have shown that they are also critically involved in cell fate determination and in the permanent cell cycle withdrawal associated with differentiation and senescence.

pRb in Bone Cell Differentiation and Senescence

Recently, work from our lab has identified important roles for each of these proteins that extends beyond a role in checkpoint control. We are presently studying the role of the retinoblastoma protein in bone cell differentiation and senescence, with the aim of identifying specific genes regulated in these processes. In addition, we are constructing mouse models of pRb loss in the bone, mimicking a common event in human osteosarcoma. This has allowed us to begin careful studies of the phenotypic consequences of pRb loss in the bone as well as provide a source of genetically defined primary cells for culture-based studies of osteoblast differentiation. These studies have revealed a key role fo pRb in the osteoprogenitor cell that restricts this cell to the bone lineage. Loss of pRb leads to an increase in the number of multipotent progenitors, with concomitant changes in cell migration, invasion, and resistance to terminal cell cycle withdrawal. These changes are reminiscent of those ascribed to the “tumor stem cell” suggesting that pRb may be a key suppressor of the generation of tumor cells from normal tissue progenitors in the bone.

Figure 1. Rb loss increases the osteoblast/adipocyte progenitor, as shown by increased adipogenesis in mouse calvarial cells, bottom.

Cyclin D1 in Development and Tumorigenesis

In a separate albeit conceptually related project, we have produced "knock-in" alleles of cyclin D1 to test for novel roles for this protein in development and tumorigenesis. The most interesting of these alleles is one that binds cdk4/6 but fails to activate the kinase. We have found that mice homozygous for this mutation have extensive mammary and retinal development, unlike their cyclin D1-null counterparts. An important goal of these experiments is to clearly define the role of cyclin D1 in mammary tumorigenesis. To that end, we crossed knockin animals with those prone to breast cancer (e.g. MMTV-neu mice) to ask the important question of whether kinase activation is needed for tumorigenesis in the breast. Interestingly, mice bearing defective cyclin D1 in the mammary gland remain resistant to tumor formation even after multiple pregnancies, and show progressive loss of lobular epithelial progenitor cells that we now identify as the initiating cells for ErbB2-dependent tumors. Further, glands lacking the oncogene show a significant shift in the types of epithelial cells produced, underscoring the role of cyclin D1 in progenitor cell expansion and fate choice in the mammary epithelium.

Figure 2. The drawing illustrates the ways by which cyclin D1 affects mammary gland development.

Cdk4 and Cdk6 in Tumorigenesis

Another major emphasis in the lab centers on the role of the cdk4 and cdk6 subunits themselves in tumorigenesis. In collaboration with Karl Münger, we have found that cdk6 plays an important but undefined role in oral cancer, apparently in collaboration with cdk4. These studies suggest the two kinases are not of equivalent function in at least some cell types, and our main goal is to understand the unique roles of cdk6 in development and tumors. To do this, we have undertaken a series of cell culture experiments using various active and dominant negative alleles of each kinase and are now extending these studies to include siRNA-mediated knockdown of the subunits. To supplement this, we have built mice bearing knockin alleles of hyperactive and “kinase dead” cdk6 (as well as null control). These animals are of great benefit as a source of primary cells for in vitro study, allow significant genetic experiments in crosses with existing animals prone to a variety of cancers, and will prove to be of lab-wide utility since cdk6 is likely to play roles in many of the processes studied in each of the above-mentioned areas. All of these studies have culminated in an overarching hypothesis that places the RB pathway at the center of cell fate decision-making steps in stem- and progenitor cells, and our major focus is now on understanding how this role of the RB pathway influences its role in cancer and development.

Figure 3.  Cdks play a key role in bone development as illustrated by the effects of the K43M knock-in allele on bone mineral density (BMD).

pRb in Senescence

Finally, each of these areas of focus on development and tumorigenesis is complemented by our ongoing studies of the mechanisms of cellular senescence. pRb is a key player in this process and we have begun to dissect its biochemical role in detail. Our recent published and unpublished work has identified several new downstream elements such as cdk5, rac1 and ERM proteins, that are key to pRb’s instigation of the tumor-suppressive senescent phenotype. We are avidly pursuing the regulation of these and their role in tumor suppression. These studies, combined with our genetic approaches described above, promise to deliver considerable new insight into the molecular basis of cancer.

Philip Hinds, PhD
Principal Investigator  

Siobhan McRee, PhD
Student in Genetics

Jodie Pietruska
Postdoctoral Scholar 

View all publications via PubMed

Bihani T, Hinds PW. 2011. Mitosis hit with an ATM transaction fee: aurora B-mediated activation of ATM during mitosis. Mol Cell 44(4):513-4. Abstract

Hinds PW. 2011. Unbearable stress: collapse of the SSeCKS/AKAP12 scaffold leads to senescence and transformation. Cell Cycle 10(17):2833-4. Abstract

Hu MG, Deshpande A, Schlichting N, Hinds EA, Mao C, Dose M, Hu GF, Van Etten RA, Gounari F, Hinds PW. 2011. CDK6 kinase activity is required for thymocyte development. Blood. 117: 6120-6131. Abstract

Huang M, Sage C, Tang Y, Lee SG, Petrillo M, Hinds PW, Chen ZY. 2011. Overlapping and distinct pRb pathways in the mammalian auditory and vestibular organs. Cell Cycle 10: 337-351. Abstract

Sosa-García B, Gunduz V, Vázquez-Rivera V, Cress WD, Wright G, Bian H, Hinds PW, Santiago-Cardona PG. 2010. A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation. PLoS One 5: e13954. Abstract

Mao D, Hinds PW. 2010. p35 is required for CDK5 activation in cellular senescence. J Biol Chem. 285: 14671-14680. Abstract

Jeselsohn R, Brown NE, Arendt l, Klebba I, Hu MG, Kuperwasser C, Hinds PW. 2010. Cyclin D1 kinase activity is required for the self-renewal of mammary stem and progenitor cells that are targets of MMTV-ErbB2 tumorigenesis. Cancer Cell 65-76. Abstract

Lazebnik MB, Tussie-Luna MI, Hinds PW, Roy AL. 2009. Williams-Beuren syndrome-associated transcription factor TFII-I regulates osteogenic marker genes. J Biol Chem. 284: 36234-36239. Abstract

Hinds PW. 2009. Keeping quiet: a key role for dipeptidyl peptidase 2. Cell Cycle 8: 2683-2684. Abstract

Kohrt DM, Crary JI, Gocheva V, Hinds PW, Grossel MJ. 2009. Distinct subcellular distribution of cyclin dependent kinase 6. Cell Cycle 8: 2837-2843. Abstract

Goel VK, Ibrahim N, Jiang G, Singhal M, Fee S, Flotte T, Westmoreland S, Haluska FS, Hinds PW, Haluska FG. 2009. Melanocytic nevus-like hyperplasia and melanoma in transgenic BRAFV600E mice. Oncogene 28: 2289-2298. Abstract

Hu MG, Deshpande A, Enos M, Mao D, Hinds EA, Hu GF, Chang R, Guo Z, Dose M, Mao C, Tsichlis PN, Gounari F, Hinds PW. 2009. A requirement for cyclin-dependent kinase 6 in thymocyte development and tumorigenesis. Cancer Res. 69: 810-818. Abstract

Zhang X, Neganova I, Przyborski S, Yang C, Cooke M, Atkinson SP, Anyfantis G, Fenyk S, Keith WN, Hoare SF, Hughes O, Strachan T, Stojkovic M, Hinds PW, Armstrong L, Lako M. 2009. A role for NANOG in G1 to S transition in human embryonic stem cells through direct binding of CDK6 and CDC25A. J Cell Biol. 184: 67-82. Abstract

Gutierrez GM, Kong E, Sabbagh Y, Brown NE, Lee JS, Demay MB, Thomas DM, Hinds PW. 2008. Impaired bone development and increased mesenchymal progenitor cells in calvaria of RB1-/- mice.  Proc Natl Acad Sci USA 105: 18402-18407. Abstract

Piscopo DM, Hinds PW. 2008. A role for the cyclin box in the ubiquitin-mediated degradation of cyclin G1. Cancer Res. 68: 5581-5590. Abstract

Hinds PW. 2008. Too much of a good thing: the Prl-3 in p53's oyster. Mol Cell 30: 260-261. Abstract

Wang Y, Ray SK, Hinds PW, Leiter AB. 2007. The retinoblastoma protein, RB, is required for gastrointestinal endocrine cells to exit the cell cycle, but not for hormone expression. Dev biol. 311: 478-486. Abstract

Landis MW, Brown NE, Baker GL, Shifrin A, Das M, Geng Y, Sicinski P, Hinds PW. 2007. The LxCxE pRb interaction domain of cyclin D1 is dispensable for murine development.. Cancer Res. 67: 7613-7620. Abstract

Tsichlis PN, Hatziapostolou M, Hinds PW. 2007. Timing is everything: regulation of Cdk1 and aneuploidy.  Dev Cell 12: 477-479. Abstract

Yang HS, Hinds PW. 2007. pRb-mediated control of epithelial cell proliferation and Indian hedgehog expression in mouse intestinal development. BMC Dev Biol. 7:6. Abstract

Deshpande A, Hinds PW. 2006. The retinoblastoma protein in osteoblast differentiation and osteosarcoma. Curr Mol Med. 6: 809-817. Abstract

Lee JS, Thomas DM, Gutierrez G, Carty SA, Yanagawa S, Hinds PW. 2006. HES1 cooperates with pRb to activate RUNX2-dependent transcription. J Bone Miner Res. 21: 921-933. Abstract

Hinds PW. 2006. A confederacy of kinases: Cdk2 and Cdk4 conspire to control embryonic cell proliferation. Mol Cell 22: 432-433. Abstract

Sage C, Huang M, Vollrath MA, Brown MC, Hinds PW, Corey DP, Vetter DE, Chen ZY. 2006. Essential role of retinoblastoma protein in mammalian hair cell development and hearing. Proc Natl Acad Sci USA 103: 7345-7350. Abstract

Yang HS, Hinds PW. 2006. Phosphorylation of ezrin by cyclin-dependent kinase 5 induces the release of Rho GDP dissociation inhibitor to inhibit Rac1 activity in senescent cells. Cancer Res 66: 2708-2715. Abstract

Landis MW, Pawlyk BS, Li T, Sicinski P, Hinds PW. 2006. Cyclin D1-dependent kinase activity in murine development and mammary tumorigenesis. Cancer Cell 9: 13-22. Abstract

Grossel MJ, Hinds PW. 2006. From cell cycle to differentiation: an expanding role for cdk6. Cell Cycle 5: 266-270. Abstract

Grossel MJ, Hinds PW. 2006. Beyond the cell cycle: a new role for Cdk6 in differentiation. J Cell Biochem 97: 485-493. Abstract