Heat Shock Proteins and their Role in Thermal

TherapiesShawn Keating

MPB 1028 PresentationSeptember 21, 2010

Heat shock proteins (HSP’s)◦ Description and family members◦ Mechanism of action

Role in Thermal Therapieso Dichotomy of Treatment Approaches

o Inhibition of HSP’s for tissue destructiono Up-regulation for immuno-modulation

o Examples of treatments

References

Outline

A family of proteins that are basally expressed in the ER, cytosol, mitochondria and nucleus of all cells. In normal conditions they function to:

1. Stabilize pre-folded/unfolded proteins for proper final folding.

2. Target proteins to lysosome/ proteosome for degradation.

3. Chaperone proteins to ER and other organelle for operation once translated.

What are HSP’s?

Rylander etal., 2005

Major targetsfor therapy

Under conditions of stress (hyperthermia, oxidative, ischemia, heavy metals, inflammation) their expression is up-regulated through transcription factors and their role in the cell extends to:

1. Binding of denatured proteins to prevent aggregation and to assist in refolding.

2. Inhibit apoptosis by upregulating NO production.

3. Immunomodulation by assisting in antigen presentation.

What are HSP’s (Cont’d)

How exactly HSP’s are able to retain function under conditions of stress is a contentious issue but their improved stability under heating is generally accredited to:

1. Increased hydrogen bonding2. Tighter hydrophobic internal packing

HSP Mechanism

HSP- 60 ChaperoninHSP-70 DnaK

HSP’s are up-regulated in tumour cells.-their protective effects confound

thermal therapies. Inhibition is one solution.

Role 1 in Thermal Therapies

Rylander etal., 2005

Inhibition of HSP-90 with geldonamycin (GA) for treatment of melanoma.

Example

Ito et.al,2009

ControlHyperGABoth

HSP’s play a role in immuno-modulation: - they act to chaperone proteins to the ER for MHC I presentation to

cytotoxic T-lymphocytes (CTL’s) and macrophage cells.- extracellular HSP’s can assist in antigen presentation to professional antigen presenting cells for stimulation of the adaptive immune response.

Role 2 in Thermal Therapies

Torigoe etal., 2009

HSP vaccinations- combining hyperthermia with HSP vaccinations extracellularly could potentially increase adaptive immune response to cancer specific antigens.

- By presenting antigens to CTL’s, the adaptive arm of the immune system is stimulated allowing long term resistance to cancer reoccurrence.

Example

Example (cont’d)

Torigoe et.al., 2009

HSP’s can inhibit apoptosis- immediately through suppression of apoptotic signals.- long term by assisting in refolding of denatured proteins.

Role 3 in Thermal Therapy

Anti-apoptotic signalling from hyperthermia induced HSP-72 expression increases oncolytic herpes virus replication and leads to increased tumour killing.

Example

Eisenberg etal., 2010

Calderwood SK, Ciocca DR. 2008. Heat Shock Proteins: Stress proteins with Janus-like properties in cancer. Int. J. Hyperthermia 24: 31-39.

Eisenberg DP, Carpenter SG, Adusumilli PS, Chan M-K, Hendershott KJ, Yu Z, Fong Y. 2010. Hyperthermia potentiates oncolytic herpes viral killing of pancreatic cancer through a heat shock protein pathway. Surgery 148:325-34.

Hildebrandt B, Wust P, Ahlers O, Dieing A, Sreenivasa G, Kerner T, Felix R, Riess H. 2002. The cellular and molecular basis of hyperthermia. Crit. Rev. Onc/Hem. 43: 33-56.

Ito A, Saito H, Mitobe K, Minamiya Y, Takahashi N, Maruyama K, Motoyama S, Katavose Y, Ogawa J. 2009. Inhibition of heat shock protein 90 sensitizes melanoma cells to thermosensitive ferromagnetic particle-mediated hyperthermia with low Curie temperature. Cancer Sci. 100: 558-564.

Manjili MH, Wang X-Y, Park J, Macdonald IJ, Li Y, Van Shie RCAA, Subjeck JR. 2002. Cancer Immunotherapy: stress proteins and hyperthermia. Int. J. Hyperthermia 18: 506-520.

Rylander MN, Feng Y, Bass J, Diller K. 2005. Thermally Induced Injury and Heat Shock Protein Expression in Cells and Tissues. Ann. N.Y. Acad. Sci. 1066: 222-242.

Torigoe T, Tamura Y, Sato N. 2009. Heat shock proteins and immunity: Applications of hyperthermia for immunomodulation. Int. J. Hyperthermia 25: 610-616.

References