Effects Of Arsenic Sulfide On NHL Cells And Treatment For Refractory And Relapsed NHL

Lymphoma, originating from lymph nodes and lymphoid tissues, is one of the major ten malignancies and divided into Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL) according to its histopathological characteristics. Based on combined chemotherapy and radiation therapy, HL has a better prognosis compared with NHL, which owns an intricate heterogeneity. Among all of the NHL, most of them (85-90%) are precursor and (or) mature B-cell lymphomas, while the remaining10-15%are precursor and (or) mature T-cell lymphomas. Although developed quickly, the R-CHOP cannot satisfy us with an enough high complete response rate especially on the Burkitt lymphoma and adult T cell lymphoma. Consequently, new drugs treating NHL, especially the relapsed and refractory NHL, are urgently needed.Arsenic sulfide, the main ingredient of realgar, was discovered inexpertly to have a perfect effect on acute promyelocytic leukemia (APL) in the1990s. Following this discovery, some stage II and stage III clinical trials based on the Compound Realgar Natural Indigo Tablet, a Chinese medicine composed by realgar and indigo, were carried out. They proved that the compound was safe and available in oral in APLs.With the development of combination chemotherapy and the usage of anti-CD20monoclonal antibody (rituximab), NHL, especially B-cell NHL, undergo a better prognosis, while the T-cell NHL, especially the peripheral T-cell lymphoma (PTCL) still bear a poor remission rate and (or) low cure rate. Some researchers suggested that the median overall survival of PTCL patients after anthracycline-based chemotherapy ranges between20and34months, whereas the5year overall survival rate ranges between28%and38%. The indolent lymphoma including follicular lymphoma (FL) and marginal zone lymphoma (MZL) can be reactive to the initial chemotherapy and resistant to the following sequential chemotherapy. There is no standard first line therapy for the relapsed and refractory NHL for the time being. To select an appropriate treatment strategy, a physician has to take the patient’s prior therapy, comorbidites, and personal preferences into consideration. Therefore, large amount of fundamental and clinical studies are conducting for the purpose of clinically healing the relapsed and refractory NHLThere are seldom some studies referring to the mechanism of As2S2on the NHL, especially the comparative studies between the B-cell lymphomas and T-cell lymphomas. Our study was aimed to investigate the effects of As2S2on B lymphoma cell lines Raji and T lymphoma cell lines Jurkat, compare the sensitiveness between the two cells and explore its mechanisms. Furthermore, we collected the clinical relapsed and refractory NHL, analyzed the statistics to provide more suggestions for the treatment of relapsed and refractory NHL. Part I Study on the mechanism of effects of arsenic sulfide (As2S2) on non-Hodgkin’s lymphoma cellsObjective:To investigate the effects of arsenic sulfide (As2S2) on B lymphoma cell lines Raji and T lymphoma cell lines Jurkat, compare the sensitiveness between the two cells and explore its mechanisms.Materials and Methods:1. Culturing cell lines Raji and Jurkat culture.2. CCK-8method to verify the cell proliferation and flow cytometry to analyse the cell apoptosis.3. RNA extraction, reverse transcription and RT-PCR method.Results:1. As2S2inhibited the cell proliferation of the NHL cells, Raji were more sensitive than Jurkat. The growth of Raji and Jurkat was inhibited by As2S2in a time-dependent and dose-dependent manner. The inhibitory rate of Raji could achieve47.64%when treated by3μM As2S2after24h and reach the peak after72h (89.45%), while the inhibitory rate of Jurkat could only achieve48.11%when treated by40μM As2S2after24h and the peak inhibitory rate of40μM As2S2after72h was only75.69%.2. As2S2could induce the apoptosis of the NHL cells, Raji were more sensitive than Jurkat. The apoptosis rate of Raji and Jurkat was induced by As2S2in a time-dependent and dose-dependent manner. The apoptosis rate could be52.50%when treated with4μM As2S2after48h, while to achieve a similar apoptosis rate, Jurkat had to be treated by30μM As2S2after72h.3. As2S2could also alter the expression levels of different apoptosis-associated genes, at which the mechanisms of Raji were different from those of Jurkat. Conclusions:1. As2S2can inhibit proliferation of the NHL cells. It is time-and concentration-dependent. B lymphoma cells are more sensitive to As2S2than those of the T lymphoma cells.2. As2S2can promote apoptosis of the NHL. It is also time-and concentration-dependent. B lymphoma cells are more sensitive to As2S2than those of the T lymphoma cells.3. The possible mechanism is that As2S2can alter the expression levels of the apoptosis associated genes by activating the associated signaling pathways.Part Ⅱ Treatment for refractory and relapsed NHLObjective:Analyse the clinical statistics, compare the effectiveness and the adverse reaction of different therapeutic schedule.Methods:We collected the33clinical data of patitents that had come to Provincial Hospital affiliated to Shandong University by retrospective analysis. All of the patients were clinically confirmed to be replased and refractory to conventional therapy. After comparing the different effectiveness and the adverse reactions of different therapeutic schedule by SPSS17.0and following up all of the patients, we analysed the advantages and disadvantages of the different therapeutic schedule.Results:1. There is no statistic significance among the precursor lymphoid tissue tumor, the mature B-cell lymphoma and the mature T-cell and NK-cell lymphoma (P>0.05).2. For the precursor lymphoid tissue tumor, the E-CHOP, auto-HSCT, VPLT, VILP, ESHAP, Hyper-CVAD, minor transplantation and lumbar puncture and intrathecal injection may increase the remission rate. For the mature B-cell lymphoma, R-DICE, RiPAD+C, Gemcitabine+Oxaliplatin, R-hyperCVAD (A) or R-hyperCVAD(B), auto-HSCT, E-CHOP, ESHAP, FMD, VP+MTX+ATO, VALP, COTP, COBP, DVD, CTHP, VIDP may increase the remission rate. While for the mature T-cell and NK-cell lymphoma, there is no recommended therapeutic schedule for the time being.3. It is recommended that the individualized therapy should be considered irreplaceable when treating the relapsed and refractory NHL.Conclusions:1. There is no difference among the precursor lymphoid tissue tumor, the mature B-cell lymphoma and the mature T-cell and NK-cell lymphoma. This may be owe to the own property of the relapsed and refractory NHL.2. The second line chemotherapy and auto hematopoitic stem cell transplantation may increase the remission rate of the relapsed and refractory NHL.3. The principle-individualized therapy has played an important role in treating the relapsed and refractory NHL.