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by Jennifer Mackey. NEPHROBLASTOMA in children Discovered by Max Wilms in 1899 WT1 is a tumor suppressor 10-15% due to WT1 inactivation. Wilms’ Tumor. Kidney MRI. (Scott et al., 2001). BUT, MUTATED WT1 IS ALSO FOUND IN OTHER CANCERS!!. BUT, MUTATED WT1 IS ALSO FOUND IN OTHER CANCERS!!

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By jennifer mackey

by Jennifer Mackey


Wilms tumor

  • NEPHROBLASTOMA in children

  • Discovered by Max Wilms in 1899

  • WT1 is a tumor suppressor

  • 10-15% due to WT1 inactivation

Wilms’ Tumor

Kidney MRI

(Scott et al., 2001)


By jennifer mackey

BUT, MUTATED WT1 IS ALSO FOUND IN OTHER CANCERS!!


By jennifer mackey

BUT, MUTATED WT1 IS ALSO FOUND IN OTHER CANCERS!!

AND AS WE WILL SEE - IT IS NOT ALWAYS A TUMOR SUPPRESSOR!!!


Wt1 is alternatively spliced to make many protein isoforms

WT1 is alternatively spliced to make many protein isoforms

(Wagner, K.D. et al., 2003)


Wt1 is a transcription factor

WT1 is a transcription factor

(Exon 5)

(Exon 9)

(Scholz, H. et al., 2005)


By jennifer mackey

WT1 is a transcription factor


Wt1 s normal biological functions

WT1’s normal biological functions

  • Development of genitourinary system

  • Development of kidney

  • Adult kidney

  • Heart development

  • Neuron development?


By jennifer mackey

WT1 KNOCKOUT MICE

  • WT1-/-

  • dies E12-birth

  • no kidneys

  • no gonads

  • severe abnormalities of retinal development

wt

KO

(Kreidberg et al., 1993)


By jennifer mackey

WT1 KNOCKOUT MICE

  • WT1-/-

  • dies E12-birth

  • no kidneys

  • no gonads

  • severe abnormalities of retinal development

  • WT1+/-

  • increased mortality due to adult onset nephrotic syndrome & renal failure


By jennifer mackey

WT1 is required for kidney development

(Scholz, H. et al., 2005)


By jennifer mackey

ADULT KIDNEY

http://en.wikipedia.org/wiki/Image:Gray1128.png


By jennifer mackey

WT1 is part of a transcriptional regulatory network

That is critical for kidney development

(Scharnhorst, V. et al., 2001)


By jennifer mackey

WT1 is part of a transcriptional regulatory network

That is critical for kidney development

(Scharnhorst, V. et al., 2001)

  • WT1 TARGET GENES INVOLVED IN KIDNEY DEVELOPMENT:

  • Amphiregulin: stimulates uretic bud

  • BCL-2: encodes antiapoptotic protein

  • E-cadherin: mesenchyme condensation


By jennifer mackey

WT1’s Role in Cancer

REMEMBER: WT1 = differentiation


By jennifer mackey

WT1’s Role in Cancer

WT1 = PROLIFERATION!!


By jennifer mackey

WT1 is a tumor suppressor

  • Wilms tumor

  • Most are sporadic and unilateral

  • 10-15% of sporadic have WT1 inactivation

  • Most others have high levels of WT1 expression

  • ~10% are bilateral and/or multifocal

http://www.sainte-justine.org/


By jennifer mackey

WT1 is a tumor suppressor

  • Wilms tumor

  • Most are sporadic and unilateral

  • 10-15% of sporadic have WT1 inactivation

  • Most others have high levels of WT1 expression

  • ~10% are bilateral and/or multifocal

  • WAGR (Wilms’ tumor, Aniridia, Genitourinary abnormalities, Mental retardation)

  • Germline deletion

  • Predisposition to WT

http://en.wikipedia.org/wiki/Image:BlackEyesAniridia.jpg


By jennifer mackey

WT1 is a tumor suppressor

  • Wilms tumor

  • Most are sporadic and unilateral

  • 10-15% of sporadic have WT1 inactivation

  • Most others have high levels of WT1 expression

  • ~10% are bilateral and/or multifocal

  • WAGR (Wilms’ tumor, aniridia, genitourinary abnormalities, mental retardation)

  • Germline deletion

  • Predisposition to WT

  • Denys-Drash Syndrome (DDS)

  • Germline mutations (missense mutation in zinc finger domain)

  • Dominant-negative activity

  • Predisposition to WT


By jennifer mackey

WT1 is a tumor suppressor

  • Wilms tumor

  • Most are sporadic and unilateral

  • 10-15% of sporadic have WT1 inactivation

  • Most others have high levels of WT1 expression

  • ~10% are bilateral and/or multifocal

  • WAGR (Wilms’ tumor, aniridia, genitourinary abnormalities, mental retardation)

  • Germline deletion

  • Predisposition to WT

  • Denys-Drash Syndrome (DDS)

  • Germline mutations (missense mutation in zinc finger domain)

  • Dominant-negative activity

  • Predisposition to WT

  • Frasier Syndrome

  • Germline point mutation in the intron 9 donor splicesite

  • Loss of KTS (-) = ratio disturbed

  • WT very rare!


By jennifer mackey

…and WT1 is an Oncogene!

Acute myeloid leukemia(AML): WT1 overexpressed in leukemic blasts

http://en.wikipedia.org/wiki/Image:Auer_rods.PNG


By jennifer mackey

…and WT1 is an Oncogene!

Acute myeloid leukemia(AML): WT1 overexpressed in leukemic blasts

Breast cancer: expression of WT1 detected in majority of BC’s evaluated

www.hopeforcancer.com/BreastCancer.html


By jennifer mackey

…and WT1 is an Oncogene!

Acute myeloid leukemia(AML): WT1 overexpressed in leukemic blasts

Breast cancer: expression of WT1 detected in majority of BC’s evaluated

Renal cell carcinoma: overexpression of WT1 in tubular epithelial cells in adulthood

http://en.wikipedia.org/wiki/Image:RCC.jpg


By jennifer mackey

GOOD NEWS!

80% of tumors can be treated successfully!!!


References

REFERENCES

Kreidberg, Jordan A. et al. 1993. WT-1 Is Required for Early Kidney Development. Cell 74: 679-691.

Loeb, David M. and Saraswati Sukumar. 2002. The Role of WT1 in Oncogenesis: Tumor Suppressor or Oncogene? International Journal of Hematology 76: 117-126.

Scharnhorst, Volkher et al. 2001. WT1 proteins: functions in growth and differentiation. Gene 273: 141-161.

Scholz, Holger and Karin M. Kirschner. 2005. A Role for the Wilms’ Tumor Protein WT1 in Organ Development. Physiology 20: 54-59.

Scott, Carly M. et al. 2001. Wilms' Tumor: A Primary Care Case Study And Differential Diagnosis. The Internet Journal of Advanced Nursing Practice 5: Number 1.

Wagner, K-D et al. 2003. The complex life of WT1. Journal of Cell Science 116: 1653-1658.

Wagner et al. 2006. Intermediate filament protein nestin is expressed in developing kidney and heart and might be regulated by the Wilms’ tumor suppressor WT1. American Journal of Physical Regul Integr Comp Physiology 291: R779-R787.


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