Shortened and intensified MJMA: an effective salvage therapy for relapsed and refractory lymphomas and a strong mobilizer of PBSCs

Chemical analyses and in vitro and in vivo toxicity of fruit methanol extract of Sechium edule var. nigrum spinosum

CONTEXT

Sechium edule (Jacq.) Sw. (Cucurbitaceae) is used in ethnomedicine, but the diversity of the varietal groups of this species has not often been considered. This is important because we previously reported that different variety of species exhibit different activities across different tumor cell lines.

OBJECTIVE

This study investigates the chemical composition and biological activities of extracts obtained from S. edule var. nigrum spinosum.

MATERIALS AND METHODS

The leukemia P388 cell line and mononuclear bone marrow cells (MNCBMs) were treated with the extract at a concentration ranging from 40 to 2370 μg/mL for cytotoxicity and viability assays. CD-1 mice were treated with 8-5000 mg/kg extract and monitored every hour for the first 24 h and subsequently for seven days for signs of toxicity (LD₅₀). In addition, the chromatographic profile of the extract was determined by HPLC.

RESULTS

The extract inhibits the proliferation of both P388 cells and MNCBMs, with IC₅₀ values of 927 and 1911 μg/mL, respectively, but reduced the viability and induced the apoptosis of only leukemia cells. The LD₅₀ was higher than 5000 mg/kg, and this concentration did not alter the blood chemistry or cell count but doubled the mitotic index in the bone marrow. The HPLC showed the presence of cucurbitacins, phloridzin, naringenin, phloretin, apigenin, and gallic, chlorogenic, vanillic, p-hydroxybenzoic, caffeic, and p-coumaric acids.

DISCUSSION AND CONCLUSION

Sechium edule var. nigrum spinosum contains bioactive compounds that explain the antiproliferative and nutraceutical activities, and its lack of physiological side effects constitutes an added value to a widely consumed vegetable.

Current status of stem cell mobilization

New advances in effective mobilization of peripheral blood stem cells have permitted a greater proportion of patients to benefit from autologous stem cell transplantation. In this review, the relative merits of peripheral blood and mobilized bone marrow are discussed. All available agents are reviewed. A critical assessment of the appropriate dosing and frequency of available growth factors is undertaken, and the most commonly used chemotherapy plus growth factor combinations are covered. Specific recommendations for patients who are poor mobilizers are dealt with including the role of plerixafor.

Role of conventional salvage multiple-drug chemotherapy in relapsed and refractory aggressive non-Hodgkin lymphomas

Autologous stem cell transplantation is the standard care for patients with relapsed or refractory aggressive non-Hodgkin lymphomas. Of the patients who are sensitive to second-line chemotherapy, approximately 40-50% are likely to be cured using this approach. The optimal salvage regimen for pre-transplant debulking is controversial and these second-line chemotherapies are particularly important for patients who cannot undergo transplantation for various reasons including age, comorbidity and insufficient stem cell collection. Numerous reports regarding this topic are available. This study evaluated reports published in the last 5 years, focusing on conventional multiple-drug second-line chemotherapies (with or without rituximab), and disregarding single-agent investigational phase-II trials. Results are encouraging, particularly when considering that the more recent and less toxic combinations appear to be equivalent to or even more favourable than previous, more aggressive approaches. Previous results obtained using a combination of mitoxantrone, carboplatin, cytarabine and methylprednisolone, are further updated and included in this study. In conclusion, the most effective conventional chemotherapy currently available for patients with relapsed or refractory non-Hodgkin lymphomas obtains complete remission rates of up to 50-70%; the achievement of a complete remission is the most important factor associated with a better outcome. Although the addition of rituximab is beneficial and safe, it is more effective in patients who have previously not been exposed to this monoclonal antibody. The addition of cycles of salvage chemotherapy to those strictly required for mobilization of peripheral blood stem cells ultimately improves the response rate.