A novel trial of topotecan, ifosfamide, and carboplatin (TIC) in children with recurrent solid tumors

All-trans retinoic acid synergizes with topotecan to suppress AML cells via promoting RARα-mediated DNA damage

Background

Chemotherapy is the only therapy option for the majority of AML patients, however, there are several limitations for this treatment. Our aim was to find a new chemotherapy strategy that is more effective and less toxic.

Methods

MTT assays and a xenograft mouse model were employed to evaluate the synergistic activity of all-trans retinoic acid (ATRA) combined with topotecan (TPT). Drug-induced DNA damage and apoptosis were determined by flow cytometry analysis with PI and DAPI staining, the comet assay and Western blots. Short hairpin RNA (shRNA) and a RARα plasmid were used to determine whether RARα expression influenced DNA damage and apoptosis.

Results

We found that ATRA exhibited synergistic activity in combination with Topotecan in AML cells, and the enhanced apoptosis induced by Topotecan plus ATRA resulted from caspase pathway activation. Mechanistically, ATRA dramatically down regulated RARα protein levels and led to more DNA damage and ultimately resulted in the synergism of these two agents. In addition, the increased antitumor efficacy of Topotecan combined with ATRA was further validated in the HL60 xenograft mouse model.

Conclusions

Our data demonstrated, for the first time, that the combination of TPT and ATRA showed potential benefits in AML, providing a novel insight into clinical treatment strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-2010-6) contains supplementary material, which is available to authorized users.

Vincristine-cyclophosphamide combination therapy positively affects T-cell subset distribution in systemic lupus erythematosus patients

Background

This study aimed to analyze the T-cell subset distribution in systemic lupus erythematosus (SLE) patients and determine whether vincristine-cyclophosphamide combination therapy can positively affect their T-cell subset distribution to keep the disease in remission.

Material/Methods

Thirteen SLE patients with ‘low activity’ (SLE Disease Activity Index (SLEDAI)≤9), 17 SLE patients with ‘high activity’ (SLEDAI>9), and 15 healthy controls were recruited. SLE patients were treated with vincristine-cyclophosphamide combination therapy. CD3⁺, CD4⁺, and CD8⁺ T-cell percentages were analyzed by flow cytometry at baseline, 3 months, 6 months, 12–24 months, and >24 months.

Results

Significantly negative correlations were observed between the CD3⁺ and CD4⁺ T-cell percentages and SLEDAI scores at baseline (r=−0.471, P=0.015; r=−0.473, P=0.015, respectively). A significantly positive correlation was observed between CD4⁺ T-cell percentage and the complement component C3 at baseline (r=0.612, P=0.002). After 3 months of combination therapy, the CD3⁺ and CD4⁺ T-cell percentages were significantly higher than the high activity baseline (P<0.01, P<0.05, respectively). After 6 months, the CD3⁺, CD4⁺, and CD8⁺ T-cell percentages were all significantly higher than the high activity baseline (P<0.01, P<0.05, P<0.05, respectively).

Conclusions

T-cell subset distributions vary across different levels of SLE disease activity with higher CD3⁺ T-cell and CD4⁺ Th cell percentages favoring lower SLE activity. As CD3⁺ T-cell and CD4⁺ Th cell percentages negatively correlate with SLEDAI, vincristine-cyclophosphamide combination therapy appears to positively affect the T-cell subset distribution in SLE patients to keep the disease in remission by increasing their CD3⁺ T-cell and CD4⁺ Th cell percentages.