Preclinical lung cancer studies

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					Preclinical lung cancer studies
  in the intramural program


              Phillip Dennis, M.D., Ph.D.
    Senior Investigator, Medical Oncology Branch
  Value of preclinical lung cancer studies


• Evaluation of new drugs, new combinations in
  relevant model systems

• Elucidation of mechanisms of lung carcinogenesis

• Validation of genes or patterns of gene expression as
  predictive or prognostic factors for patients with lung
  cancer
                             Tools
• Cell lines
   – Primary human bronchial/alveolar epithelial cells
   – Human immortalized bronchial epithelial cells
       • BEAS-2B et al., HBEC et al.
   – Human lung cancer cell lines
       • SCLC, NSCLC
   – Syngeneic murine lung adenocarcinoma cell lines from
     tobacco carcinogen-driven model
• Mouse models
   – Xenograft
   – Tobacco carcinogen-driven
   – Genetically engineered
• Rat model
   – Radon +/- smoking
  Advantages of carcinogen-driven and
 genetically engineered mouse models of
               lung cancer

• Prevention and treatment studies possible
• Physiologic analysis of tumor microenvironment
  (immunocompetent models)
• Preclinical PK, PD, toxicology- compare to human
• Imaging- longitudinal assessment of lung tumor
  growth/regression
   Relevance of models to human lung
            cancer subsets
• Current/former smokers
   – Tobacco carcinogen-driven
      • NNK (mutant Kras-dependent)
      • urethane
   – GEM
      • Mutant K-Ras
      • Mutant LKB1
      • nAchR subunits
• Never smokers
   – EGFR-driven (L858R/T790M)
   – XPC (DNA damage)
          Bench to bedside examples

• Current/former smokers
   – Rapamycin to prevent tobacco carcinogen-induced lung
     tumors


• Never smokers
   – Triciribine (Akt inhibitor) to overcome resistance to EGFR
     TKIs.
A common pathway for different lung cancer subsets

               Smokers                      Never smokers
                                              Etiology?

            nAChR         Kras mut       EGFR mut/amp


                          PI3K
  X               X
                         T
  LKB1            PTEN


                                 T
         AMPK             Akt        triciribine

                   TSC2          T
                          mTOR       rapamycin
Tumor suppressor genes
    Bench to bedside example- A lung cancer prevention
     model for current or former smokers (K-Ras driven)

Study Schema
                      NNK or saline                                   rapamycin



I. Tx of established tumors                                          50%  tumor size


   II. Short term treatment                                          Ø size, multiplicity


  III. Continuous treatment                                          90%  tumor size, multiplicity
            Week of study
                              0       7   16            26      32


                                               Clin Cancer Res. 2007 Apr 1;13(7):2281-9
      A working model for prevention of tobacco carcinogen-
               induced lung tumors by rapamycin
                                                          Anti-CD25 ab
                                                          Genetic ablation

Exposure to tobacco carcinogens

                                                                             X
                                       Permissive environment                Foxp3
                                        cytotoxic T cell response
                          X    Foxp3




              Kras G12D           genetic/epigenetic changes
                                  proliferation
                                                                     X           Kras G12D


                    X                                                   X

                          Rapamycin                             Rapamycin



                                                                                  PLoS ONE. 2009;4(3):e5061
 Bench to bedside example- A model for never smokers
 whose lung cancers become resistant to an EGFR TKI
Hypothesis- Akt inhibition will resensitize cells to an EGFR TKI
In vitro model
H1975 cells (resistant to EGFR TKI) (L858R/T790M mutation)
Triciribine (Akt inhibitor)
Gefitinib/erlotinib (EGFR TKI)
                                                                                                                                                   Total Death Assay
                                                            Gefitinib
                                                            Triciribine                                                 25
                                                            Combined                                                                                        DMSO
                                                                                                                        20                                  TCN
                             120

                                                                                                                                                            Erlot
                             100                2.5M Gefitinib




                                                                                                              % Death
                                                                                                                        15
                                                                                                                                                            TCN + Erlot
 % Growth




                             80

                             60                                                                                         10
                             40
                                                                                       Synergism
                             20
                                                                                                                         5

                               0
            0.0001   0.001      0.01   0.1       1     10        100                                                     0
                             -20
                                                                                                                                     48 Hr H1975
                                             M Triciribine


                                                                                                                        DMSO   Gef   TCN Combo

                                                                                                   P-EGFR
                                                                                                   (Y1068)
                                                                              EGFR
                                                                          T




                                             Gefitinib/erlotinib
                                                                                                   EGFR

                                                                                                   P-ERK
                                                                              Akt    ERK
                                                                          T




                                                        triciribine                            (Y202/204)

                                                                                                   P-AKT
                                                                                                   (S473)
                                                                              Pras40               P-Pras40
                                                                                                     (T246)
Bench to bedside example- A model for never smokers
whose lung cancers become resistant to an EGFR TKI


     H1975 xenografts
                                          1600
                                                     vehicle

                                          1400       50 mg/kg erlotinib
                                                     0.3 mg/kg TCN-P
              Median tumor volume (mm3)   1200
                                                     50 mg/kg erlotinib + 0.3 mg/kg TCN-P
                                          1000

                                           800

                                           600

                                           400

                                           200

                                             0
                                                 0               5                  10      15
                                                                          Day
       Bench to bedside example- A model for never smokers
       whose lung cancers become resistant to an EGFR TKI-
                  An inducible L858R/T790M transgenic model of lung cancer
                                                       P-EGFR                      Total EGFR


Specific induction of
L858R/T790M
mutations in Clara
cells after 12 wk of
doxycycline




           Before triciribine             QuickTime™ and a
                                 Motion JPEG OpenDML d ecompressor
                                   are neede d to see this picture.
                                                                               QuickTime™ and a
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                                                                        are neede d to see this picture.




             Day 9 triciribine            QuickTime™ and a
                                 Motion JPEG OpenDML d ecompressor
                                                                               QuickTime™ and a
                                                                      Motion JPEG OpenDML d ecompressor
                                   are neede d to see this picture.     are neede d to see this picture.
                            Conclusions

•   Preclinical lung cancer expertise within the intramural program is
    extensive.
•   Mouse models with relevance to many molecular subsets of human
    lung cancer improve our understanding of lung cancer and aid targeted
    drug development.
•   The barriers between preclinical and clinical lung cancer research are
    minimized in the intramural program
     •   A lung cancer prevention trial with rapamycin and a lung cancer treatment
         trial combining triciribine with erlotinib (Tarceva) are in the approval process.
     •   The development of new mouse models based on results from human lung
         cancer GWAS is ongoing.

				
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