Involvement Of P73 In Anti-tumor Activity Of A Naphthoquinone Analog

Object:To investigate the correlation between the anti-tumor activity ,such as growth inhibition and apoptosis induction,of a naphthoquinone analog,termed 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone(DDN) and the expression pattern of p73 .Methods:1,Hela cells were divided into the four groups which were treated with various concentration of DDN( ranged 0-20uM) for 24 hours.The effects of DDN on the growth inhibition were exammed by MTT,and the apoptosis index(AI) were measured by TUNEL.The expression rate of TAp73/DNp73 were detected by RT-PCR at the same time.2,To research if the anti-cancer activity of DDN is p73 related.Contrasted by the missense oligonucleotide(MSODN) and DDN alone,we interference the effects of DDN(15uM) with TAp73-specific antisense oligonucleotide(ASODN).24 hours later,we verified the intervention effect by RT-PCR.The inhibition on the growth of Hela cells was exammed through the method of MTT,and the apoptosis index was measured by TUNEl.Result 1,DDN15-20uM possessed superior growth inhibition and apoptosis induction effect in comparison to others.{MTT 0.1459±0.0081[20uM]≈0.2300±0.0615[15uM]<0.6489±0.2046[10uM]<1.2804±0.1543[0uM](F=117.701 P<0.01);AI 72.75±3.69%[15uM] ≈70.75±3.67%[20uM]>39.00±2.27%[10uM]>3.90±1.25%[0uM] (F=905.799 P<0.01)};Compaired with others ,DDN15uM can increase the expression rate of TAp73/DNp73 more efficiently{9.4114±1.1742[15uM]>5.9088±0.7886[10uM]>3.1400±0.6263[20uM]≈2.8563±0.2981[0uM] (F=11.969 P<0.01)}.2,The antitumor activity of DDN can be blocked by the intervention of TAp73-specific antisense oligonucleotide.{ MTT 0.4882±0.1025[ASODN+DDN]>0.1553±0.0231[MSODN+DDN]≈0.2300±0,6147[DDN alone](F=63.423 P<0.01) AI 29.00±3.02%[ ASODN+DDN]<71.50±3.55%[ MSODN+DDN]≈72.75±3.69%[DDN alone](F=384.672 P<0.01)}.3,The expression rate of TAp73/DNp73 showed closely related to the effects on the growth inhibition and apoptosis induction of DDN< rs=-0.410 P＜0.01； rs=0.635 P＜0.01 respectively >.Conclusion 1,the rate of TAp73/DNp73 mRNA was increasing while DDN inducing the growth inhibition and apoptosis.2,The increased TAp73/DNp73 expression rate would be important to the antitumor process of DDN.These results imply that p53-indepent TAp73-depent apoptosis and growth inhibition are involved in DDN-induced antitumor process.