Project description:Transcriptional profiling of human leukemia?HL-60 cells comparing ATRA treated HL-60 cells with ATRA plus ATO. Goal was to determine the effects of ATO on ATRA induced differentiation of HL-60 cells. Two-condition experiment, ATRA vs. ATRA plus ATO treated HL-60 cells.
Project description:Transcriptional profiling of human leukemia HL-60 cells comparing ATRA treated HL-60 cells with ATRA plus ATO. Goal was to determine the effects of ATO on ATRA induced differentiation of HL-60 cells.
Project description:Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) combination safely cures fatal acute promyelocytic leukemia, but the mechanisms underlying their action and synergy remain elusive. ATRA inhibits APL, breast and liver cancers by targeting isomerase Pin1, a master regulator of oncogenic signaling. Here we show that ATO targets Pin1 and cooperates with ATRA to exert potent anticancer activity. ATO inhibits and degrades Pin1, and suppresses its oncogenic function by noncovalent binding to Pin1’s active site. ATRA increases cellular ATO uptake through upregulating aquaporin-9. ATO and ATRA, at clinically safe doses, cooperatively ablate Pin1 to block numerous cancer-driving pathways and inhibit the growth of triple-negative breast cancer cells and tumor-initiating cells in cell and animal models including patient-derived orthotopic xenografts, similar to Pin1 CRISPR knockout, which is substantiated by comprehensive protein and microRNA analyses. Thus, synergistic Pin1 inhibition by ATO and ATRA offers an attractive approach to combating breast and other cancers.
Project description:Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) combination safely cures fatal acute promyelocytic leukemia, but the mechanisms underlying their action and synergy remain elusive. ATRA inhibits APL, breast and liver cancers by targeting isomerase Pin1, a master regulator of oncogenic signaling. Here we show that ATO targets Pin1 and cooperates with ATRA to exert potent anticancer activity. ATO inhibits and degrades Pin1, and suppresses its oncogenic function by noncovalent binding to Pin1’s active site. ATRA increases cellular ATO uptake through upregulating aquaporin-9. ATO and ATRA, at clinically safe doses, cooperatively ablate Pin1 to block numerous cancer-driving pathways and inhibit the growth of triple-negative breast cancer cells and tumor-initiating cells in cell and animal models including patient-derived orthotopic xenografts, similar to Pin1 CRISPR knockout, which is substantiated by comprehensive protein and microRNA analyses. Thus, synergistic Pin1 inhibition by ATO and ATRA offers an attractive approach to combating breast and other cancers.
Project description:Acute promyelocytic leukemia (APL) is a hematological disease characterized by a balanced reciprocal translocation that leads to the synthesis of the oncogenic fusion protein PML-RARα. APL is mainly managed by a differentiation therapy based on the administration of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). However, therapy resistance, differentiation syndrome, and relapses require the development of new low-toxicity therapies based on the induction of blasts differentiation. Here, we performed a high-throughput gene expression profile of the maturation inducible APL cell line NB4 untreated or exposed to ATRA.
Project description:Acute promyelocytic leukemia (APL) is a hematological disease characterized by a balanced reciprocal translocation that leads to the synthesis of the oncogenic fusion protein PML-RARα. APL is mainly managed by a differentiation therapy based on the administration of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). However, therapy resistance, differentiation syndrome, and relapses require the development of new low-toxicity therapies based on the induction of blasts differentiation. Here, we performed a high-throughput gene expression profile of the ATRA-resistant acute promyelocytic leukemia (APL) cellline (aka R4) treated with a CHK1 inhibitor or DMSO as control.
Project description:We describe a case of a child affected by a relapsed PML/RARA-negative acute promyelocytic leukemia (APL) rescued by a combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) and subsequent HSCT. We provide evidence of the presence of a chimeric viral transcript generated through genomic integration of a Torque Teno Mini Virus sequence into RARA intron 2, the recurrent breakpoint of all chimeric RARA fusions found in APL. This generates an in-frame TTMV/RARA chimeric fusion that is highly expressed at disease diagnosis and relapse and fully cleared at remission achievement.
Project description:The synergistic combination of All-Trans Retinoic Acid (ATRA) and Arsenic Trioxide (ATO) has transformed acute promyelocytic leukemia (APL) from a terminal disease into a curable one. However, the molecular basis for the APL-specific synergy remains to be fully defined. In this work, we studied the mechanism that drives the unique efficacy of ATRA/ATO on APL cells. We found that the ATRA/ATO combination generates a high level of endogenous genotoxic stress, leading to exacerbated accumulation of DNA damage in APL cellular models and patient samples. Crucially, we found that ATRA-treatment triggers the ubiquitin-proteasome -mediated degradation of key DNA damage response proteins, including ATM and FANCD2. This APL-specific event is independent of PML-RARA turnover and creates a profound vulnerability to genotoxic stress, rendering APL cells more susceptible to the combined genotoxic stress from the ATRA-ATO combination. Our findings reveal that the synergized induction of genotoxic stress and the concurrent impairment of the DNA damage response mechanisms constitute a lethal "Double-Hit" that promotes APL-specific apoptosis. This study provides a novel paradigm for understanding therapeutic synergy and suggests that targeting DDR protein stability may extend the success of differentiation therapy to a broader range of leukemia.
Project description:To identify the top 20 up-regulated genes in CD34+ cells from AML patients in comparison with healthy donors, we examined the microarray gene expression profile of CD34+ blasts from patients with newly diagnosed AML vs CD34+ normal cells from healthy donors. Despite the fact that combined therapy of all-trans retinoic acid (ATRA) with arsenic trioxide (ATO) or chemotherapy dramatically improves the prognosis of patients with APL, these regimens can cause systemic infections and secondary leukemias. Here we report that expression of the pseudokinase Tribble 3 (TRIB3) associates positively with APL progression and therapeutic resistance. The elevated TRIB3 expression promotes APL by interacting with PML-RARa and suppressing its sumoylation, ubiquitylation and degradation. This represses PML nuclear body assembly, p53-mediated senescence, cell differentiation, and supports cellular self-renewal. Genetically inhibiting Trib3 expression or disturbing the TRIB3/PML-RARa interaction produces potent therapeutic efficacy against APL and has synergic anti-APL effects when used in combination with ATRA or ATO by promoting PML-RARa degradation and PML expression. Our study provides new insight into APL pathogenesis and a new therapeutic option against APL.
Project description:To identify the top 20 up-regulated genes in NB4 TRIB3 shRNA cells in comparison with NB4 control shRNA cells, we examined the microarray gene expression profile of these groups above. Despite the fact that combined therapy of all-trans retinoic acid (ATRA) with arsenic trioxide (ATO) or chemotherapy dramatically improves the prognosis of patients with acute promyelocytic leukemia (APL), these regimens can cause systemic infections and secondary leukemias. Here we report that expression of the pseudokinase Tribble 3 (TRIB3) associates positively with APL progression and therapeutic resistance. The elevated TRIB3 expression promotes APL by interacting with PML-RARa and suppressing its sumoylation, ubiquitylation and degradation. This represses PML nuclear body assembly, p53-mediated senescence, cell differentiation, and supports cellular self-renewal. Genetically inhibiting Trib3 expression or disturbing the TRIB3/PML-RARa interaction produces potent therapeutic efficacy against APL and has synergic anti-APL effects when used in combination with ATRA or ATO by promoting PML-RARa degradation and PML expression. Our study provides new insight into APL pathogenesis and a new therapeutic option against APL.