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Stem Cells & Cancer. Norman Iscove M.D. Multiple kinds of blood cell. Bone marrow is a factory for blood cells. Multiple assembly lines in marrow. The neutrophil assembly line. The neutrophil assembly line. The neutrophil assembly line. The neutrophil assembly line.
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Stem Cells & Cancer Norman Iscove M.D.
Stem cells self-renew Stem cell Committed precursors Differentiating precursors
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell Committed precursor
Stem cells self-renew Stem cell Committed precursor Differentiating precursor
Stem cells self-renew Stem cell Committed precursors Differentiating precursors
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell Committed precursor
Stem cells self-renew Stem cell Committed precursor Differentiating precursor
Stem cells self-renew Stem cell Committed precursors Differentiating precursors
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell
Stem cells self-renew Stem cell Committed precursor
Stem cells self-renew Stem cell Committed precursor Differentiating precursor
Stem cells are the key transplantable element in marrow Imaging of stem cell transplantation Stem cells can be purified 1 stem cell time Other precursors Stem cells 1 in 4,000 1 in 20,000 Cao et al., PNAS 101:221-226, 2004
Normal blood cell formation • blood cells produced by maturation of precursor cells • precursor cells have finite proliferative capacity and lifespan • stem cells are multipotent • stem cells constantly replenish the precursor cells • stem cells make new stem cells - "self-renewal" • self-renewal is unique to stem cells and is essential for continued existence of blood cell production
Differing biology of precursor cells and stem cells proliferative
Differing biology of precursor cells and stem cells killed by anti-cancer drugs
Differing biology of precursor cells and stem cells quiescent
Differing biology of precursor cells and stem cells relatively resistant to anti-cancer drugs
Differing biology of precursor cells and stem cells • >95% of marrow cells can be depleted by treatment with certain anti-cancer drugs • stem cells may entirely resist short-term chemotherapy Despite massive reduction in marrow bulk by chemotherapeutic agents, marrow will rapidly regenerate from surviving stem cells
Stem cells in normal mammary glands 1 in 1500 mammary ductal cells can regenerate an entire gland 1 purified cell is sufficient Stingl et al, Nature 439:993, 2006
Leukemia Leukemia Normal
Leukemia initiating cells are rare and distinct leukemia cells human leukemia cells 1 in 50,000 cells FACS time Stem cells 1 % Remaining cells 99 % florid leukemia Dick et al, 1997
Breast tumour initiating cells are rare and distinct Human breast carcinoma cells breast tumour cells FACS time Stem cells 1 % Remaining cells 99 % Breast carcinoma Clarke et al, 2003
Brain tumour initiating cells are rare and distinct Human brain tumour cells brain tumour cells FACS time Stem cells 1 % Remaining cells 99 % Brain tumour Dirks et al, 2004
Colon tumour initiating cells are rare and distinct Human colon carcinoma cells colon carcinoma cells FACS time Stem cells 1 % Remaining cells 99 % Colon carcinoma Dick et al, 2006
Cancer stem cells • cancers, like normal tissues, constitute differentiating systems • bulk cells produced by cancer systems have abnormal properties clinical disease • bulk cells have finite lifespans • cancer stem cells are rare and physically distinct from the bulk of tumour cells • cancer stem cells are essential to the continued existence of cancer systems • the biology of cancer stem cells differs from the rest of the cells in a tumour
Differing biology of precursor cells and stem cells relatively resistant to anti-cancer drugs killed by anti-cancer drugs
Tumour stem cell Stem cell concepts will change treatment strategies treatment remission relapse conventional bulk reduction eventual cure stem cell targetted combined anti-stem and bulk reduction early cure Jean Wang