Frödin Group

We study how protein kinase cascades activated by extracellular signaling molecules regulate normal cell behaviour and how their dysregulation may cause cancer and other diseases.

We focus on protein kinases in the signaling network used by growth factor receptors and G-protein coupled receptors. Kinases in these pathways have established or putative importance in cancer, where they are hyper-activated due to mutations in receptors, RAS, PI3-Kinase or other proto-oncogenes or by being mutated themselves. These kinase pathways are also important in diabetes, inflammatory disease, fibrosis, neurological and other disorders and are therefore widely explored for therapeutic intervention.

We develop and use new CRISPR/Cas9 genome editing methods, chemical-genetic kinase inhibitor technology and classical mouse genetics for our research. We use these technologies to create cell and mouse models to determine if specific protein kinases are drivers of disease, to unravel the mechanism(s) whereby they may promote disease, and to test the kinases as drug targets.

 

The kinase signaling network used by growth factor and G-protein coupled receptors is crucial for regulation of normal cell function and its dysregulation is causally linked to major diseases. The AGC kinases (orange) are important effector kinases in this network.

Examples of current research

Functional liver cancer genetics:  identifying kinases as novel oncogenic drivers

We identify kinases as novel drivers of liver cancer by using in vivo CRISPR/Cas9 genome editing in mice that takes outset in tumor genome sequencing. Thus, we recently established a DNAJB1-PKAα fusion mutant as causative driver of fibrolamellar hepatocellular carcinoma: we delivered CRISPR/Cas9 to the adult mouse liver through hydrodynamic tail vein injection to re-create the exact 400 Kb chromosomal deletion that generates DNAJB1-PKAα in patients. Intriguingly, nearly all mice developed fibrolamellar-like tumors. Furthermore, whole-exome sequencing of tumors showed no co-driver mutations, demonstrating that DNAJB1-PKAα is the all-dominant driver of this cancer. We are now testing DNAJB1-PKAα as drug target in our models which may pave the way for a therapy of this lethal cancer. Using similar functional genetics, we have proceeded to explore other kinases as drivers and drug targets in liver cancer.

 

In vivo genome editing of mouse liver via hydrodynamic tail vein injection demonstrates that a DNAJB1-PKAα fusion kinase found in patients is the driver of fibrolamellar carcinoma. See Engelholm et al. (2017) Gastroenterology 

RAS-activated kinase cascades

The RAS-activated MAP kinase cascade ranks among the most fundamental signaling pathways in normal physiology and disease and the RSK and MSK kinases are important mediators. Taking outset in a constitutively active RSK2 mutant we developed to demonstrate RSK as key mediator of RAS-elicited invasiveness of epithelial and carcinoma cells (movie), we have now generated mice with CRE-inducible, constitutively active RSK2. We use these mice, RSK/MSK knockout mice and chemical-genetic RSK/MSK mice (see below) as powerful tools to decipher the roles of the RAS-MAP kinase pathway in normal physiology, cancer and fibrosis.

Our chemical-genetic kinase inhibitor technology: testing kinases as drug targets

We have developed a novel technology to target a kinase-of-interest for pharmacological inhibition. This technology is based on the compound fmk that specifically inhibits the kinases RSK1, RSK2 and RSK4 via two selectivity residues (Cys/Thr) absent from the remaining 500 kinases. We use CRISPR/Cas9 editing to create “platform” cells or mice with RSKs point-mutated at the selectivity filter such that fmk has no target. In these “platforms” we then introduce the Cys/Thr selectivity filter in a kinase-of-choice which now is inhibitable by fmk. We use this powerful system to study the biological roles of kinases and test them as drug targets.

Principle of our chemical-genetic kinase inhibitor technology (left). Example with human leukemic K562 cells in which MSK1 has been made inhibitable by fmk (right). The technology exploits our efficient methods for FACS-based and ssODN-based genome editing - see e.g. Lonowski et al. (2017) Nature Protocols; Chen et al (2011) Nature Methods. (som link)

Selected publications

1. Niola M, Dagnæs-Hansen M and Frödin M (2018) ”In vivo editing of the adult mouse liver using CRISPR/Cas9 and hydrodynamic tail vein injection”. Methods in Molecular Biology, in the press

2. Frank SR, Köllmann CP, Luong P, Galli GG, Zou L, Bernards A, Getz G, Calogero RA, Frödin M and Hansen SH (2018). “p190 RhoGAP promotes contact inhibition in epithelial cells by repressing YAP activity”. Journal of Cell Biology, in the press

3. Engelholm LH, Riaz A, Serra D, Dagnæs-Hansen F, Johansen JV, Santoni-Rugiu E, Hansen SH, Niola F and Frödin M (2017). “CRISPR/Cas9 engineering of adult mouse liver demonstrates that the Dnajb1-Prkaca gene fusion is sufficient to induce tumors resembling fibrolamellar hepatocellular carcinoma”. Gastroenterology, 153:1662-1673

4. Lonowski LA, Narimatsu Y, Riaz A, Delay CE, Yang Z, Niola F, Duda K, Ober EA, Clausen H, Wandall HH, Hansen S, Bennett EP and Frödin M (2017). “Genome editing using FACS enrichment of nuclease expressing cells and Indel Detection by Amplicon Analysis (IDAA)”. Nature Protocols, 12:581-603.

5. Niola F and Frödin M (2017). “Generation of model cell lines using ssODN knockin donors and FACS-based genome editing”. In “Genome editing: from TALENs, ZFNs and CRISPRs to molecular surgery”, edited by Krishnarao Appasani, Cambridge University Press, in the press

6. Frank SR, Kollmann CP, van Lidth de Jeude J, Thiagarajah JR, Engelholm LH, Frödin M and Hansen SH (2017). “The focal adhesion-associated proteins DOCK5 and GIT2 comprise a rheostat in control of epithelial invasion”. Oncogene, 36:1816-28

7. Duda K, Lonowski LA, Kofoed-Nielsen, M., Ibarra A, Delay C, Kang Q, Yang Z, Pruett-Miller SM, Bennett EP, Wandal HH, Davis GD, Hansen SH and Frödin M (2014). ”High-efficiency genome editing via 2A-coupled co-expression of zinc finger nucleases or CRISPR/Cas nickase pairs”. Nucleic Acids Research, 42:e84.

8. Serafimova IM, Pufall MA, Krishnan S, Duda K, Cohen MS, Miller RM, McFarland JM, Maglathlin RL, Frödin M and Taunton J (2012). “Reversible covalent targeting of noncatalytic cysteines with chemically tuned electrophiles”. Nature Chemical Biology, 8:471-6, doi: 10.1038/nchembio.925.

9. Frank SR, Bell JH, Frödin M and Hansen SH (2012). “A bPix-PAK2 complex confers protection against Scrib-dependent and cadherin-mediated apoptosis”. Current Biology, 22:1747-1754.

10. Duda K and Frödin M (2012). “Stimuli that activate MSK in cells and the molecular mechanism of activation”. In “MSKs”, edited by J Simon C Arthur, Madame Curie Bioscience Database, Landes Biosciences.

11. Chen F, Pruett-Miller, SM, Huang Y, Gjoka M, Duda K, Taunton J, Collingwood TN, Frödin M and Davis GD (2011) “High frequency genome editing using ssODNs and zinc finger nucleases”. Nature Methods, 8:753-755

12. Doehn U, Hauge C, Frank SR, Jensen CJ, Duda K, Nielsen JV, Cohen MS, Johansen JV, Winther BR, Lund LR, Winther O, Taunton J, Hansen SH and Frödin M (2009) “RSK is a principal effector of the RAS-ERK pathway to induce a pro-motile/invasive gene program and phenotype in epithelial cells”. Molecular Cell, 35:511-522

13. Hauge C, Antal TL, Hirschberg D, Doehn U, Thorup K, Idrissova L, Hansen K, Jensen ON, Jørgensen TJD, Biondi RM and Frödin M (2007) “Mechanism for activation of the growth factor-activated AGC kinases by turn motif phosphorylation”. EMBO Journal, 26:2251-61

14. Frödin M (2007) “A RSK kinase inhibitor reporting its selectivity in vivo”. Nature Chemical Biology, 3:138-9.