Acute lymphoblastic leukemia is still an incurable disease with resistance to therapy developing in the majority of patients. We investigated the effect of TPEN, an intracellular zinc chelator, in Jurkat and in <i >ex vivo</i> acute lymphoblastic leukemia (ALL) cells resistant to chemotherapy. Changes of nuclei morphology, reactive oxygen species generation, presence of hypodiploid cells, phosphatidylserine translocation, mitochondrial membrane depolarization, immunohistochemical identification of cell death signalling molecules, and pharmacological inhibition were assayed to detect the apoptotic cell death pathways. We found that TPEN induces apoptosis in both types of cells by a molecular oxidative stress pathway involving <svg style="vertical-align:-3.27605pt;width:136.39999px;" id="M1" height="17.65" version="1.1" viewBox="0 0 136.39999 17.65" width="136.39999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,13.5)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g> <g transform="matrix(.012,-0,0,-.012,12.763,17.588)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g><g transform="matrix(.012,-0,0,-.012,19.1,5.35)"><path id="x2022" d="M455 252q0 -79 -57 -136t-136 -57q-80 0 -136 56q-56 58 -56 137q0 77 56 135q57 57 136 57q84 0 138 -56q55 -55 55 -136z" /></g><g transform="matrix(.012,-0,0,-.012,25.323,5.35)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g> <g transform="matrix(.017,-0,0,-.017,37.65,13.5)"><path id="x3E" d="M512 230l-437 -233v58l378 199v2l-378 200v58l437 -233v-51z" /></g><g transform="matrix(.017,-0,0,-.017,52.337,13.5)"><path id="x48" d="M729 650v-28q-62 -5 -76 -19.5t-14 -75.5v-404q0 -62 13.5 -76t75.5 -19v-28h-268v28q65 5 79.5 19t14.5 76v199h-341v-199q0 -62 14 -76t76 -19v-28h-263v28q61 5 74.5 19t13.5 76v404q0 62 -14 76t-76 19v28h259v-28q-58 -5 -71 -19t-13 -76v-162h341v162
q0 61 -13.5 75.5t-72.5 19.5v28h261z" /></g> <g transform="matrix(.012,-0,0,-.012,65.362,17.588)"><use xlink:href="#x32"/></g> <g transform="matrix(.017,-0,0,-.017,71.7,13.5)"><use xlink:href="#x4F"/></g> <g transform="matrix(.012,-0,0,-.012,84.4,17.588)"><use xlink:href="#x32"/></g> <g transform="matrix(.017,-0,0,-.017,95.462,13.5)"><path id="x226B" d="M512 230l-437 -233v58l378 199v2l-378 200v58l437 -233v-51zM780 230l-437 -233v58l378 199v2l-378 200v58l437 -233v-51z" /></g><g transform="matrix(.017,-0,0,-.017,114.705,13.5)"><path id="x4E" d="M719 650v-28q-43 -2 -62 -15t-22 -44q-6 -47 -6 -169v-403h-31l-426 524h-2v-251q0 -111 6 -169q4 -37 24 -50.5t72 -16.5v-28h-237v28q45 2 64.5 16t23.5 49q6 62 6 171v220q0 54 -3 68.5t-17 32.5q-16 19 -34.5 26.5t-54.5 10.5v28h147l418 -502h3v246q0 117 -7 166
q-4 34 -24.5 47t-73.5 15v28h236z" /></g><g transform="matrix(.017,-0,0,-.017,127.335,13.5)"><path id="x46" d="M493 503l-29 -4q-13 56 -28 80q-13 22 -35.5 29.5t-78.5 7.5h-76q-22 0 -27.5 -5t-5.5 -27v-238h103q66 0 82.5 12t25.5 62h29v-193h-29q-9 54 -25.5 67t-82.5 13h-103v-181q0 -64 15 -78.5t84 -19.5v-28h-272v28q61 5 74.5 19.5t13.5 78.5v399q0 64 -13 78t-72 19v28
h440q1 -40 10 -147z" /></g> </svg>-<i >κ</i>B (JNK/c-Jun) <svg style="vertical-align:-3.27599pt;width:54.75px;" id="M2" height="15" version="1.1" viewBox="0 0 54.75 15" width="54.75" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,10.862)"><use xlink:href="#x3E"/></g><g transform="matrix(.017,-0,0,-.017,14.749,10.862)"><path id="x70" d="M169 380l92 53q26 16 49 16q80 0 128.5 -56t48.5 -133q0 -108 -72.5 -180.5t-176.5 -91.5q-38 1 -69 18v-131q0 -57 13 -70t71 -18v-27h-236v27q49 5 61 17t12 61v452q0 48 -9.5 58.5t-56.5 16.5v24q66 11 145 43v-79zM169 346v-270q37 -39 94 -39q63 0 101.5 50
t38.5 134q0 78 -38.5 123t-95.5 45q-45 0 -100 -43z" /></g><g transform="matrix(.017,-0,0,-.017,23.657,10.862)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8
l-26 -65h-233z" /></g><g transform="matrix(.017,-0,0,-.017,31.816,10.862)"><path id="x33" d="M285 378v-2q65 -13 102 -54.5t37 -97.5q0 -57 -30.5 -104.5t-74 -75t-85.5 -42t-72 -14.5q-31 0 -59.5 11t-40.5 23q-19 18 -16 36q1 16 23 33q13 10 24 0q58 -51 124 -51q55 0 88 40t33 112q0 64 -39 96.5t-88 32.5q-29 0 -64 -11l-6 29q77 25 118 57.5t41 84.5
q0 45 -26.5 69.5t-68.5 24.5q-67 0 -120 -79l-20 20l43 63q51 56 127 56h1q66 0 107 -37t41 -95q0 -42 -31 -71q-22 -23 -68 -54z" /></g><g transform="matrix(.017,-0,0,-.017,44.701,10.862)"><use xlink:href="#x3E"/></g> </svg> loss <svg style="vertical-align:-3.3907pt;width:48.049999px;" id="M3" height="15.65" version="1.1" viewBox="0 0 48.049999 15.65" width="48.049999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,11.362)"><path id="x394" d="M600 0h-557v24l268 633l28 8l261 -641v-24zM497 50l-194 489l-196 -489h390z" /></g><g transform="matrix(.017,-0,0,-.017,10.959,11.362)"><path id="x3A8" d="M699 659l10 -27q-31 -17 -42 -39t-21 -74l-14 -69q-10 -53 -26 -82t-47 -53q-58 -45 -156 -48v-145q0 -58 14.5 -74t71.5 -20v-28h-256v28q57 4 71 20t14 74v145q-104 3 -163 49q-29 23 -45 54t-25 82l-12 72q-11 62 -20 77q-11 19 -38 31l10 27q74 -11 106 -50
q20 -24 30 -78l11 -60q16 -92 48.5 -128t97.5 -41v227q0 57 -13.5 73t-66.5 20v28h245v-28q-53 -4 -66.5 -20t-13.5 -73v-227q75 4 103.5 37.5t45.5 132.5l10 58q8 51 33 80q35 38 104 49z" /></g> <g transform="matrix(.012,-0,0,-.012,23.288,15.45)"><path id="x1D45A" d="M766 88q-40 -45 -83.5 -72.5t-63.5 -27.5q-39 0 -16 103l49 224q15 68 -10 68q-36 0 -112.5 -78.5t-105.5 -133.5q-27 -101 -38 -165q-35 -4 -77 -18l-6 6q42 153 70 288q12 55 10 78t-19 23q-38 0 -114 -80.5t-101 -131.5q-24 -68 -41 -165q-36 -3 -76 -18l-8 6
q56 202 87 347q7 33 -3 33q-8 0 -31.5 -17.5t-41.5 -35.5l-12 28q42 45 84 72t63 27q44 0 10 -124l-20 -75h2q92 121 193 178q36 21 64 21q62 0 28 -159l-8 -37h2q50 67 103.5 112t94.5 65q39 19 62 19q60 0 23 -156l-45 -189q-9 -39 2 -39q17 0 71 49z" /></g> <g transform="matrix(.017,-0,0,-.017,38.012,11.362)"><use xlink:href="#x3E"/></g> </svg> caspase-3, AIF > chromatin condensation/DNA fragmentation. Interestingly, TPEN induced apoptosis independently of glucose; leukemic cells are therefore devoid of survival capacity by metabolic resistance to treatment. Most importantly, TPEN cytotoxic effect can eventually be regulated by the antioxidant N-acetyl-cysteine and zinc ions. Our data suggest that TPEN can be used as a potential therapeutic prooxidant agent against refractory leukemia. These data contribute to understanding the importance of oxidative stress in the treatment of ALL.
Cell death mechanisms and regulation
