OXIDATIVE STRESS CAN DIFFERENTIALLY MODULATE WNT/β- CATENIN AND JNK SIGNALLING RELATIONSHIPS IN PRIMARY VERSUS METASTATIC CRC CELLS

BACKGROUND Oxidative stress plays a role in mediating survival and progression of CRC and in promoting resistance to therapy. H2O2 mediated oxidative stress may also modulate the canonical and non-canonical Wnt/-catenin signalling pathway in CRC cells linked to the JNK pathway and metabolic program of tumor microenvironment. Currently, it is unclear how oxidative stress can differentially modulate WNT/-catenin and jnk signalling relationships in primary versus metastatic CRC, with mutated APC. AIMS. To evaluate the molecular relationship among oxidative distress and JNK/Wnt/β-catenin signalling in APC mutated cell models from primary and metastatic CRC. METHODS. SW480 (primary) and SW620 (metastatic) cells were treated with JNK inhibitor SP600125 and H2O2, (from 0.05mM to 0,005mM). We assessed: cell viability by MTS; JNK/Wnt/-Catenin signaling modulation of gene and protein expression by qRT-PCR and ICC, respectively; metabolic changes by Seahorse analyser. RESULTS. Increasing concentrations of H2O2 had different effects on the two cell lines, particularly at 0.05 mM. Exposure to H2O2 induced a significant reduction in the viability of SW480 cells already at a concentration of [0.005mM], which remained constant in the range [0.05-0.005mM]. While, in SW620, cell viability increased at H2O2 [0.05mM]. After JNK inhibition by SP600125, and stimulation with H2O2 both cells show a reduction in viability. In SW480, SP600125 reduced gene expression of APC, LEF1, cMYC and IL8, respect to H2O2 [0.05mM] alone. In SW620, SP600125 combined with H2O2 [0.05mM] induced an increase in gene expression of APC, LEF1, cMYC, JUN/AP1 and IL8 compared to H2O2 [0.05mM] alone. SP600125 and H2O2 combined reduced -catenin and APC protein expression. Only in SW620 oxygen consumption rate was reduced by H2O2 and SP600125 combined. CONCLUSIONS. Our results indicated that H2O2 increases the Warburg effect in CRC affecting JNK/Wnt/-catenin pathway and APC retained functions. These results could support personalized therapeutic approaches for CRC progression.