Profiling of residual breast cancers after neoadjuvant chemotherapy  identifies DUSP4 deficiency as a mechanism of drug resistance.
Neoadjuvant chemotherapy (NAC) induces a pathological complete response (pCR) in ~30% of patients with breast cancer. However, many patients have residual cancer after chemotherapy, which correlates with a higher risk of metastatic recurrence and poorer outcome than those who achieve a pCR. We hypothesized that molecular profiling of tumors after NAC would identify genes associated with drug resistance. Digital transcript counting was used to profile surgically resected breast cancers after NAC. Low concentrations of dual specificity protein phosphatase 4 (DUSP4), an ERK phosphatase, correlated with high post-NAC tumor cell proliferation and with basal-like breast cancer (BLBC) status. BLBC had higher DUSP4 promoter methylation and gene expression patterns of Ras-ERK pathway activation relative to other breast cancer subtypes. DUSP4 overexpression increased chemotherapy-induced apoptosis, whereas DUSP4 depletion dampened the response to chemotherapy. Reduced DUSP4 expression in primary tumors after NAC was associated with treatment-refractory high Ki-67 scores and shorter recurrence-free survival. Finally, inhibition of mitogen-activated protein kinase kinase (MEK) synergized with docetaxel treatment in BLBC xenografts. Thus, DUSP4 downregulation activates the Ras-ERK pathway in BLBC, resulting in an attenuated response to anti-cancer chemotherapy.
Department of Medicine, Vanderbilt-Ingram Comprehensive Cancer Center, Vanderbilt University, Nashville, Tennessee, USA.
Justin M
JM
Balko
Rebecca S
RS
Cook
David B
DB
Vaught
María G
MG
Kuba
Todd W
TW
Miller
Neil E
NE
Bhola
Melinda E
ME
Sanders
Nara M
NM
Granja-Ingram
J Joshua
JJ
Smith
Ingrid M
IM
Meszoely
Janine
J
Salter
Mitch
M
Dowsett
Katherine
K
Stemke-Hale
Ana M
AM
González-Angulo
Gordon B
GB
Mills
Joseph A
JA
Pinto
Henry L
HL
Gómez
Carlos L
CL
Arteaga
D000818:Animals; D017209:Apoptosis; D001943:Breast Neoplasms / Q000145:classification / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics*; D002470:Cell Survival; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D054637:Dual-Specificity Phosphatases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D052138:Genes, Neoplasm / Q000235:genetics; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D054639:Mitogen-Activated Protein Kinase Phosphatases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual; D016612:Paraffin Embedding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014015:Tissue Banks; D016707:Tissue Fixation; D016896:Treatment Outcome; D018631:ras Proteins / Q000378:metabolism
D019394:Ki-67 Antigen; D012333:RNA, Messenger; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D054639:Mitogen-Activated Protein Kinase Phosphatases; C490583:DUSP4 protein, human; D054637:Dual-Specificity Phosphatases; D018631:ras Proteins