Prevention and synergistic control of Ph+ ALL by a DNA vaccine and 6-mercaptopurine

Continuous Complete Remission in Two Patients with Acute Lymphoblastic Leukemia and Severe Fungal Infection Following Short-Term, Dose-Reduced Chemotherapy

Spontaneous remission in acute lymphoblastic leukemia (ALL) is a rare phenomenon, which typically involves a pattern of feverish or septic disease followed by quick but mostly transient remission. We report on two male patients (46-year-old (pt. 1) and 19-year-old (pt. 2)) with CD20 positive, BCR-ABL negative common B-ALL. Patient 1 had received dexamethasone and cyclophosphamide (1.2 g) as a prephase therapy, followed by rituximab and a cumulative dose of 200 mg daunorubicin combined with 2 mg vincristine as an induction therapy. Patient 2 was treated with a reduced therapy regimen (Vincristine 1 mg, dexamethasone and 80 mg daunorubicin, 12-month mercaptopurine maintenance) due to (alcohol-related) toxic liver failure and pontine myelinolysis. Both patients developed severe septic disease just few days into induction treatment. Patient 1 suffered from pulmonary mycosis, which had to be resected eventually. Histological work-up revealed invasive mucor mycosis. Patient 2 presented with elevated serum aspergillus antigen and radiographic pulmonary lesions, indicative of pulmonary mycosis. In both patients, chemotherapy had to be interrupted and could not be resumed. Both patients recovered under broad antimicrobial, antifungal and prophylactic antiviral therapy and achieved molecular complete remission. At data cut-off remissions had been on-going for 34 months (pt. 1) and 8 years (pt. 2). Short-term, reduced intensity induction chemotherapy accompanied by severe fungal infections was followed by long-lasting continuous complete remissions in ALL. Thus, we hypothesize that infection-associated immunogenic responses may not only prevent early relapse of ALL but could also eradicate minimal residual disease. The effects of combined cytotoxic therapy and severe infection may also be mimicked by biomodulatory treatment strategies aiming at reorganizing pathologically altered cellular signaling networks. This could reduce toxicity and comorbidity in adult patients requiring leukemia treatment. Therefore, these two cases should encourage systematic studies on how leukemia stroma interaction can be harnessed to achieve long lasting control of ALL.

Syntheses and Biological Evaluation of Novel Hydroxamic Acid Derivatives Containing Purine Moiety as Histone Deacetylase Inhibitors

The novel hydroxamates containing purine scaffold were designed, synthesized and screened for their biological activities as histone deacetylase (HDAC) inhibitors. Some of them exhibited excellent acti-HDACs activities and antiproliferative activities, the most promising compound was 7m'. Western blot analysis indicated the compounds 7f', 7l', 7m', 7o' could increase histone H3 acetylation levels in HCT116 and K562 cell lines, and 7m' increased the level of acetyl histone H3 in a dose-dependent manner, which is similar to the behavior of suberoylanilide hydroxamic acid (SAHA). Molecular docking study revealed that the conformation of 7m' in the active site of HDAC2 was similar to positive drug SAHA, which were oriented with the hydroxamic acid towards the catalytic center and formed metal binding with zinc ion.

Dendritic cell vaccine against leukemia: advances and perspectives

As with many other types of malignancies, sustainable eradication of leukemia has been a challenge. This is related to the inevitable failure of conventional chemotherapeutic agents and radiation therapy to target the relatively quiescent leukemia stem cells, which are believed to have multidrug resistance, antiapoptotic capacity and enhanced DNA repair mechanisms allowing them to evade the immune system. Considering other therapeutic options that are minimally toxic to normal cells and effectively target not only the majority and more differentiated cancer cells, but also the rare residual leukemia cells, is of paramount importance. A number of immunotherapeutic options have been proposed to counter this challenge. One of the remarkable achievements in the field of immunotherapy has been the successful use of antigen presenting cells as vehicles of tumor/pathogenic antigens to the T-cell compartments. This review will focus on advances and perspectives of this arm of immunotherapy against leukemia.