Effects of high-dose IFNalpha2b on regional lymph node metastases of human melanoma: modulation of STAT5, FOXP3, and IL-17.
OBJECTIVE
Signal transducer and activator of transcription 5 (STAT5) and STAT3 oppose one another in regulation of the reciprocal development of CD4+CD25+FOXP3+ regulatory T cells (Treg) and T helper 17 (Th17). A reduction in STAT3 is associated with up-regulation of Treg, and STAT5 activation promotes Treg differentiation or function while constraining Th17 generation. The effects of IFNalpha on STAT signaling in relation to tumor tissue Treg and Th17 have not been documented in humans beyond the observations that IFNalpha2b down-regulates STAT3.


METHODS
Following diagnostic biopsy and before definitive surgery, 20 doses of high-dose IFNalpha2b (HDI) were administered to patients with stage IIIB melanoma who gave written informed consent. Lymph node biopsies, in which both total STAT3 and phosphorylated STAT3 were down-regulated by HDI, were probed with STAT5, FOXP3, CD4, and interleukin 17 (IL-17) with immunohistochemistry and/or immunofluorescence techniques.


RESULTS
The percentage of FOXP3+ lymphocytes determined by immunohistochemistry was up-regulated from 3.06 +/- 0.65% to 9.86 +/- 1.27% (n = 13, P = 0.0002), and this observation was confirmed by immunofluorescence evaluation of CD4+FOXP3+ Tregs. HDI induced STAT5 up-regulation (five cases observed) in melanoma cells and lymphocytes but did not induce the generation of IL-17-expressing lymphocytes. Increased STAT5 expression was associated with increased FOXP3 expression among lymphocytes, and STAT5 was constitutively activated among both melanoma cells and lymphocytes.


CONCLUSIONS
IFNalpha2b up-regulates STAT5 and down-regulates STAT3, in conjunction with up-regulation of Treg and inhibition of IL-17-expressing lymphocytes in melanoma tissues. These findings suggest that the effects of IFNalpha may be potentiated through interference with the response of Tregs and/or STAT5.
Wang
Wenjun
W
Department of Medicine, Division of Hematology/Oncology, Melanoma and Skin Cancer Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213-2584, USA.
Edington
Howard D
HD
Rao
Uma N M
UN
Jukic
Drazen M
DM
Radfar
Arash
A
Wang
Hong
H
Kirkwood
John M
JM
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D051858:Forkhead Transcription Factors / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use*; D020381:Interleukin-17 / Q000032:analysis*; D008207:Lymphatic Metastasis; D008545:Melanoma / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology / Q000556:secondary; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor / Q000032:analysis*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000502:physiology
D000970:Antineoplastic Agents; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D020381:Interleukin-17; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor