Serious neutropenia in ALL patients treated with L-asparaginase may be avoided by therapeutic monitoring of the enzyme activity in the circulation

Drug sensitivity patterns of HHV8 carrying body cavity lymphoma cell lines

Background

Primary effusion lymphoma (PEL) is a rare KSHV/HHV8-associated high-grade non-Hodgkin's lymphoma (NHL) of B-cell origin, characterized by serous effusions in body cavities. Most patients are HIV-infected men with severe immunosuppression and other HHV8-associated diseases such as Kaposi's sarcoma (KS). The prognosis for those infected is poor, with a median survival of less than 6 months in most cohorts. Sustained complete remission is rare. High-dose chemotherapy regimens are used to improve remission rate and survival. The aim of the present study was to compare the drug sensitivity pattern of the available primary effusion (body cavity based) lymphoma-derived cell lines in order to find additional, potentially effective drugs that are not included in current chemotherapy treatment protocols.

Methods

We have analyzed 11 cell lines against 27 frequently used cytostatic drugs in short term (3 days) survival assays using automated high throughput confocal microscopy.

Results

All cell lines showed a distinct, individual drug sensitivity pattern. Considering the in vitro used and clinically achieved drug concentration, Vinorelbine, Paclitaxel, Epirubicin and Daunorubicin were the most effective drugs.

Conclusions

We suggest that inclusion of the above drugs into PEL chemotherapy protocols may be justified. The heterogeneity in the drug response pattern however indicated that assay-guided individualized therapy might be required to optimize therapeutic response.

Hodgkin-lymphoma-derived cells show high sensitivity to dactinomycin and paclitaxel

Depending on stage and risk factors, up to 30% of patients with advanced Hodgkin lymphoma (HL) progress or relapse. Patients with pleural effusions have a particularly poor prognosis and this stage of HL is regularly resistant to chemotherapy. All currently available HL cell lines are derived from late stage HL patients. In the present study we measured the sensitivity of these HL lines against the 26 most frequently used cytostatic drugs. We used a novel fluorescent short-term survival assay where the cell was incubated with the drugs for 4 days. The precise number of differentially stained live and dead cells was determined using a custom-built automated laser confocal fluorescent microscope. We found that HL cells, independently of their origin, showed very similar sensitivity patterns for several of the drugs. All HL cell lines were highly sensitive to dactinomycin, paclitaxel and etoposide. Our data suggest that the inclusion of dactinomycin and paclitaxel into chemotherapy protocols against late stage Hodgkin lymphoma with pleural effusion may be justified.

Effect of frequently used chemotherapeutic drugs on cytotoxic activity of human cytotoxic T-lymphocytes

Tumors are considered to be possible targets of immunotherapy using stimulated and expanded cytotoxic T-lymphocytes (CTL). It is important to consider the drug-induced effects when chemotherapeutic regimens and CTL-mediated immunotherapy is planned to be used in parallel. In this study, we characterized the effect of 29 frequently used chemotherapeutic agents on the cytotoxic activity of autologous and allogeneic CTLs. We found that treatment of CTLs with the following drugs: docetaxel, vincristine, chlorambucil, mitomycin C, oxaliplatin, doxorubicin, and bleomycin effectively inhibited CTL-mediated killing, without affecting their viability. On the other hand, the following drugs enhanced or permitted efficient CTL-mediated killing in vitro at concentrations comparable with the maximally achieved therapeutic concentration in vivo in humans: daunorubicin, prednisolone, vinorelbine, cisplatin, methotrexate, hydroxyurea, cytarabine, cyclophosphamide, topotecan, epirubicin, fluorouracil, carboplatin, asparaginase, 6-mercaptopurine, and bortezomib. Our results could potentially be used in the future to design new CTL-based adjuvant immunotherapy protocols.

Effect of frequently used chemotherapeutic drugs on the cytotoxic activity of human natural killer cells

Tumors are considered to be possible targets of immunotherapy using stimulated and expanded autologous or allogeneic natural killer (NK) cells mismatched for MHC class I molecules and inhibitory NK receptors. NK cell-based immunoadjuvant therapies are carried out in combination with standard chemotherapeutic protocols. In the presented study, we characterized the effect of 28 frequently used chemotherapeutic agents on the capacity of NK cells to kill target cells. We found that treatment of NK cells with the drugs vinblastine, paclitaxel, docetaxel, cladribine, chlorambucil, bortezomib, and MG-132 effectively inhibited NK cell-mediated killing without affecting the viability of NK cells. On the other hand, the following drugs permitted efficient NK cell-mediated killing even at concentrations comparable with or higher than the maximally achieved therapeutic concentration in vivo in humans: asparaginase, bevacizumab, bleomycin, doxorubicin, epirubicin, etoposide, 5-fluorouracil, hydroxyurea, streptozocin, and 6-mercaptopurine.

Cytotoxic drug sensitivity of Epstein-Barr virus transformed lymphoblastoid B-cells

BACKGROUND

Epstein-Barr virus (EBV) is the causative agent of immunosuppression associated lymphoproliferations such as post-transplant lymphoproliferative disorder (PTLD), AIDS related immunoblastic lymphomas (ARL) and immunoblastic lymphomas in X-linked lymphoproliferative syndrome (XLP). The reported overall mortality for PTLD often exceeds 50%. Reducing the immunosuppression in recipients of solid organ transplants (SOT) or using highly active antiretroviral therapy in AIDS patients leads to complete remission in 23-50% of the PTLD/ARL cases but will not suffice for recipients of bone marrow grafts. An additional therapeutic alternative is the treatment with anti-CD20 antibodies (Rituximab) or EBV-specific cytotoxic T-cells. Chemotherapy is used for the non-responding cases only as the second or third line of treatment. The most frequently used chemotherapy regimens originate from the non-Hodgkin lymphoma protocols and there are no cytotoxic drugs that have been specifically selected against EBV induced lymphoproliferative disorders.

METHODS

As lymphoblastoid cell lines (LCLs) are well established in vitro models for PTLD, we have assessed 17 LCLs for cytotoxic drug sensitivity. After three days of incubation, live and dead cells were differentially stained using fluorescent dyes. The precise numbers of live and dead cells were determined using a custom designed automated laser confocal fluorescent microscope.

RESULTS

Independently of their origin, LCLs showed very similar drug sensitivity patterns against 29 frequently used cytostatic drugs. LCLs were highly sensitive for vincristine, methotrexate, epirubicin and paclitaxel.

CONCLUSION

Our data shows that the inclusion of epirubicin and paclitaxel into chemotherapy protocols against PTLD may be justified.