ROLE OF HUMANIN IN THE RESPONSE OF CANCER CELLS TO CHEMOTHERAPY

ZUCCATO CAMILA; MORENO AYALA MARIELA A.; GOTTARDO MARÍA FLORENCIA; PIDRE MATIAS LUIS; ASAD ANTONELA; NICOLA CANDIA ALEJANDRO JAVIER; ROMANOWSKI VÍCTOR; SEILICOVICH ADRIANA; CANDOLFI MARIANELA

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "SimSun", "宋体"; font-size: 12pt; }p.ctl { font-family: "Mangal", "Cambria Math", serif; font-size: 12pt; }Humanin(HN) is a mitochondrial-derived peptide withpotent cytoprotective action in many cell types. Although HN canprotect normal cells against toxic effects of chemotherapy, the roleof this peptide in tumor pathogenesis is not well understood. We havepreviously observed that recombinant HN inhibits the response oftriple negative breast cancer (TNBC) cells to cytotoxic stimuli,facilitating tumor progression and chemoresistance invivo.Here we aimed to evaluate whether chemotherapy modulates theexpression of HN in cancer cell types that are characterized by theirchemoresistance: TNBC and glioblastoma (GBM) cells. Weevaluatedthe expression of HN in murine 4T1 TNBC cells and in human U251 GBMcells by flow cytometry following serumdeprivation and chemotherapy with Doxorubicin (DOXO), Cisplatin (CP)or Temozolomide (TMZ). Expression of HN in 4T1 TNBC cells wasupregulated by DOXO (500 nM) and CP (1 μM, p<0.05), but not byserum deprivation. In U251 GBM cells, the expression of HN wasincreased by CP (5 μM) and TMZ (15 μM), and at a lesser extent byserum deprivation (p<0.05). We next evaluated the role ofendogenous HN in the apoptotic response of TNBC cells, using aplasmid encoding a short hairpin RNA to block HN (pUC.shHN). Toreadily assess transduction efficiency, the plasmid also encodes thered fluorescent protein dTomato as a reporter gene. Transfection ofTNBC 4T1 tumor cells with pUC.shHN increased the percentage ofapoptotic cells when compared to cells transfected with controlplasmid, as assessed by flow cytometry after staining with propidiumiodide (p<0.05). When transfected 4T1 cells were incubated withdifferent concentrations of DOXO, pUC.shHN increased theirchemosensitivity, reducing their clonogenic capacity when incubatedwith Doxo (p<0.05). Our findings indicate thatblockade of HN expression could constitute a therapeutic strategy toimprove the efficacy of chemotherapy in chemoresistant cancer cells.