PMID- 19128456
OWN - NLM
STAT- MEDLINE
DCOM- 20090303
LR  - 20230718
IS  - 1476-4598 (Electronic)
IS  - 1476-4598 (Linking)
VI  - 8
DP  - 2009 Jan 7
TI  - Inhibition of HIF-1alpha activity by homeodomain-interacting protein kinase-2 
      correlates with sensitization of chemoresistant cells to undergo apoptosis.
PG  - 1
LID - 10.1186/1476-4598-8-1 [doi]
AB  - BACKGROUND: Homeodomain-interacting protein kinase-2 (HIPK2), a transcriptional 
      co-repressor with apoptotic function, can affect hypoxia-inducible factor 1 
      (HIF-1) transcriptional activity, through downmodulation of its HIF-1alpha 
      subunit, in normoxic condition. Under hypoxia, a condition often found in solid 
      tumors, HIF-1alpha is activated to induce target genes involved in 
      chemoresistance, inhibition of apoptosis and tumor progression. Here, we 
      investigated whether the HIPK2 overexpression could downregulate HIF-1alpha 
      expression and activity in tumor cells treated with hypoxia-mimicking condition, 
      and evaluated whether HIPK2-dependent downregulation of HIF-1alpha could 
      sensitize chemoresistant tumor cells to adriamycin (ADR)-induced apoptosis. 
      METHODS: Tumor cell lines carrying wild-type p53, siRNA p53, or mutant p53 were 
      overexpressed with HIPK2 (full length or catalytic inactive mutant) and treated 
      with cobalt chloride (CoCl2) to mimic hypoxia, in the presence or absence of ADR 
      treatment. HIF-1alpha expression was measured by semiquantitative 
      reverse-transcriptase (RT)-PCR and Western immunoblotting and HIF-1 activity was 
      evaluated by luciferase assay using reporter plasmid containing hypoxia response 
      elements (HREs) upstream of luciferase gene. HIF-1 target genes, including 
      multidrug resistance 1 (MDR1) and the antiapoptotic Bcl2 were determined by 
      RT-PCR. Cell survival and apoptosis were measured by colony assay and cleavage of 
      the caspase-3 substrate PARP, respectively. RESULTS: Overexpression of HIPK2 
      resulted in downmodulation of cobalt-stabilized HIF-1alpha protein and HIF-1alpha 
      mRNA levels, with subsequent inhibition of HIF-1 transcriptional activity. MDR1 
      and Bcl-2 gene expression was downmodulated by HIPK2 overexpression in 
      cobalt-treated cells. Inhibition of HIF-1 transcriptional activity was dependent 
      on HIPK2 catalytic activity. HIPK2 overexpression did not induce per se apoptosis 
      of cobalt-treated cells, on the contrary it sensitized cobalt-treated cells to 
      ADR-induced apoptosis, regardless of their p53 status. CONCLUSION: The ability of 
      HIPK2 to restore the apoptosis-inducing potential of chemotherapeutic drug in 
      hypoxia-mimicking condition and therefore to sensitize chemoresistant tumor cells 
      suggests that HIPK2 may induce fundamental alterations in cell signaling 
      pathways, involving or not p53 function. Thus potential use of HIPK2 is promising 
      for cancer treatment by potentiating cytotoxic therapies, regardless of p53 cell 
      status.
FAU - Nardinocchi, Lavinia
AU  - Nardinocchi L
AD  - Department of Experimental Oncology, Molecular Oncogenesis Laboratory, Regina 
      Elena Cancer Institute, 00158 Rome, Italy. nardinocchi@ifo.it
FAU - Puca, Rosa
AU  - Puca R
FAU - Sacchi, Ada
AU  - Sacchi A
FAU - D'Orazi, Gabriella
AU  - D'Orazi G
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090107
PL  - England
TA  - Mol Cancer
JT  - Molecular cancer
JID - 101147698
RN  - 0 (Antibiotics, Antineoplastic)
RN  - 0 (Carrier Proteins)
RN  - 0 (HIF1A protein, human)
RN  - 0 (Hypoxia-Inducible Factor 1, alpha Subunit)
RN  - 0 (Tumor Suppressor Protein p53)
RN  - 80168379AG (Doxorubicin)
RN  - EC 2.7.1.- (HIPK2 protein, human)
RN  - EC 2.7.11.1 (Protein Serine-Threonine Kinases)
SB  - IM
MH  - Antibiotics, Antineoplastic/pharmacology
MH  - Apoptosis/*physiology
MH  - Blotting, Western
MH  - Carrier Proteins/*metabolism
MH  - Cell Hypoxia/drug effects/physiology
MH  - Cell Line, Tumor
MH  - Doxorubicin/pharmacology
MH  - Drug Resistance, Neoplasm/*physiology
MH  - Gene Expression Regulation, Neoplastic/*physiology
MH  - Humans
MH  - Hypoxia-Inducible Factor 1, alpha Subunit/*metabolism
MH  - Protein Serine-Threonine Kinases/*metabolism
MH  - Reverse Transcriptase Polymerase Chain Reaction
MH  - Transfection
MH  - Tumor Suppressor Protein p53/metabolism
PMC - PMC2628864
EDAT- 2009/01/09 09:00
MHDA- 2009/03/04 09:00
PMCR- 2009/01/07
CRDT- 2009/01/09 09:00
PHST- 2008/11/04 00:00 [received]
PHST- 2009/01/07 00:00 [accepted]
PHST- 2009/01/09 09:00 [entrez]
PHST- 2009/01/09 09:00 [pubmed]
PHST- 2009/03/04 09:00 [medline]
PHST- 2009/01/07 00:00 [pmc-release]
AID - 1476-4598-8-1 [pii]
AID - 10.1186/1476-4598-8-1 [doi]
PST - epublish
SO  - Mol Cancer. 2009 Jan 7;8:1. doi: 10.1186/1476-4598-8-1.