Background: The resistance of cancerous cells to chemotherapy remains the main limitation for cancer treatment at present. Doxorubicin (DOX) is a potent antitumor drug that activates the ubiquitin-proteasome system, but unfortunately it also activates the Nuclear factor kappa B (NF-кB) pathway leading to the promotion of tumor cell survival. MG132 is a drug that inhibits I kappa B degradation by the proteasome-avoiding activation of NF-кB. In this work, we studied the sensitizing effect of the MG132 proteasome inhibitor on the antitumor activity of DOX. Methods: U937 human leukemia cells were treated with MG132, DOX, or both drugs. We evaluated proliferation, viability, apoptosis, caspase-3, -8, and −9 activity and cleavage, cytochrome c release, mitochondrial membrane potential, the Bcl-2 and Bcl-XL antiapoptotic proteins, senescence, p65 phosphorylation, and pro- and antiapoptotic genes. Results: The greatest apoptosis percentage in U937 cells was obtained with a combination of MG132 + DOX. Likewise, employing both drugs, we observed a decrease in tumor cell proliferation and important caspase-3 activation, as well as mitochondrial membrane potential loss. Therefore, MG132 decreases senescence, p65 phosphorylation, and the DOX-induced Bcl-2 antiapoptotic protein. The MG132 + DOX treatment induced upregulation of proapoptotic genes BAX, DIABLO, NOXA, DR4, and FAS. It also induced downregulation of the antiapoptotic genes BCL-XL and SURVIVIN. Conclusion: MG132 sensitizes U937 leukemia cells to DOX-induced apoptosis, increasing its anti-leukemic effectiveness.

Here we present a male patient with acute myeloid leukemia (AML) initially diagnosed as M5 and with karyotype 46,XY. After induction therapy, he underwent a HLA-matched allogeneic hematopoietic stem cell transplantation, and six years later he relapsed as AML M1 with an abnormal karyotype //47,XX,+10[2]/47,XX,+11[3]/48,XX,+10,+11[2]/46,XX[13]. Based on this, we tested the possibility of donor cell origin by FISH and molecular STR analysis. We found no evidence of Y chromosome presence by FISH and STR analysis consistent with the success of the allogeneic hematopoietic stem cell transplantation from the female donor. FISH studies confirmed trisomies and no evidence of MLL translocation either p53 or ATM deletion. Additionally 28 fusion common leukemia transcripts were evaluated by multiplex reverse transcriptase-polymerase chain reaction assay and were not rearranged. STR analysis showed a complete donor chimerism. Thus, donor cell leukemia (DCL) was concluded, being essential the use of cytological and molecular approaches. Pediatric DCL is uncommon, our patient seems to be the sixth case and additionally it presented a late donor cell leukemia appearance. Different extrinsic and intrinsic mechanisms have been considered to explain this uncommon finding as well as the implications to the patient.

Introduction: Despite the improvement in survival in acute lymphoblastic leukemia (ALL), there are still cases with evasion of chemotherapy-induced apoptosis. The IKK/NF-κB signaling pathway contributes to antiapoptotic gene expression. Pentoxifylline (PTX) inhibits IkB phosphorylation, blocking NF-κB and antiapoptotic activity. Methods: We conducted a randomized, double-blind clinical trial on pediatric ALL patients undergoing induction therapy, assigning them to PTX or placebo group. Bone marrow aspirates were obtained on days 1, 8, 15, and 22. Apoptosis was assessed using Annexin-V/propidium iodide. Results: Results indicated that the PTX group exhibited higher apoptosis on day-8 (41.3% vs. 19.4%, p =0.029) and day-15 (35.0% vs. 14.2%, p <0.01). On day-8, the PTX group displayed an MRD of 0.25% vs. 18.2% (p <0.01) in placebo group; on day-15, the PTX group demonstrated an MRD of 0.09% vs. 1.4% (p =0.02). Patients achieving an MRD <0.01% on day-8 demonstrated a 3-year Overall Survival (OS) of 81.6% vs. 58.3% (p =0.03); on day-15, patients with MRD <0.01% had a 3-year OS of 77.9% vs. 54.5% (p =0.03). The PTX group achieved an MRD of <0.01% earlier on days-8 and 15, along with a higher apoptosis rate, indicating a more favorable therapeutic response. In the entire cohort, patients achieving MRD <0.01% on day-8 or 15 displayed superior OS. Conclusion: Our study demonstrates that PTX enhances apoptosis and reduces MRD in pediatric acute lymphoblastic leukemia patients.Clinical trial registration: https://clinicaltrials.gov/, identifier NCT02451774.

Hodgkin lymphoma (HL) is a common neoplasm in adolescents and young adults, primarily treated with doxorubicin (DOX) and bleomycin (BLM), which may cause severe adverse effects. The cure rate decreases to 75% in advanced-stage disease, highlighting the need for improved treatment strategies. Pentoxifylline (PTX), an NF-κB pathway inhibitor, enhances chemotherapy-induced apoptosis in cancer cells, making it a promising candidate for HL therapy. This study assessed the effects of PTX, DOX, and BLM on apoptosis, proliferation, and senescence in Hs-445 HL cells. Cell viability and clonogenicity were measured by spectrophotometry and spectrofluorimetry, while apoptosis, caspase activity, cell cycle, mitochondrial membrane potential (ΔΨm), proliferation, and senescence were analyzed via flow cytometry. Gene expression was assessed by qPCR. PTX significantly induced apoptosis, especially when combined with BLM or BLM+DOX (triple therapy), and modulated gene expression by upregulating proapoptotic and downregulating antiapoptotic markers. PTX increased caspase-3, -8, and -9 activity and disrupted the ΔΨm, particularly with BLM or triple therapy. Furthermore, PTX abolished DOX-induced G2 cell cycle arrest, reduced proliferation, and clonogenicity, and reversed DOX- and BLM-induced senescence. In conclusion, PTX induces apoptosis in HL cells, enhances DOX and BLM cytotoxicity synergistically, and reverses senescence, suggesting its potential as an adjunct therapy for HL.

Background: Hodgkin lymphoma (HL) comprises 6% of pediatric cancers, showing bimodal incidence in adolescence/young-adult and over 50 years. Characterized by Reed-Sternberg cells, HL is classified as classic/nodular lymphocytic predominant by WHO. Hypereosinophilia (>1,500/µL eosinophils) occurs in 15% of HL cases. Case report: A 17-year-old female presented with weight loss, night sweats, and malaise. Examination showed enlarged lymph nodes, splenomegaly, and palmoplantar erythema. Bloodwork revealed eosinophilia, hypoalbuminemia, and elevated lactate dehydrogenase levels. Bone marrow confirmed eosinophilic predominance. Lymph node biopsy diagnosed nodular sclerosis classical Hodgkin lymphoma (NS-cHL). PET-CT scan identified cervical, mediastinal, abdominal and spleen tumoral activity, classified as classical Hodgkin lymphoma or nodular lymphocyte-predominant Hodgkin lymphoma according to WHO criteria. OEPA/COPDAC treatment initiated, follow-up PET-CT showed incomplete metabolic response. She subsequently underwent radiotherapy, achieving complete metabolic response after treatment. Conclusion: This rare case illustrates profound hypereosinophilia concomitant with HL. Despite an extensive literature search, similar presentations are rarely reported in the literature. This case highlights an uncommon association between classical Hodgkin lymphoma and unusually high levels of hypereosinophilia, supported by the clinical course and the marked decline in eosinophil counts after lymphoma-directed therapy.