Clinicopathological and genetic landscape of plasmablastic lymphoma in Taiwan

Plasmablastic lymphoma (PBL) is an aggressive large B-cell lymphoma with a terminal B-cell differentiation phenotype and is frequently associated with immunodeficiency. We aimed to investigate the clinicopathological and immunophenotypic features, genetic alterations, and mutational landscape of PBL in Taiwan. We retrospectively recruited 26 cases. Five (5/18; 28%) patients were HIV-positive and 21 (81%) presented extranodally. There were two morphological groups: one with purely monomorphic large cells (85%) and the other comprising large cells admixed with plasmacytic cells (15%). Phenotypically, the tumors expressed MYC (8/10; 80%), CD138 (20/26; 77%), and MUM1 (20/20; 100%), but not CD20 (n = 26; 0%). Fourteen (54%) cases were positive for EBV by in situ hybridization; the EBV-positive cases were more frequently HIV infected (p = 0.036), with extranodal presentation (p = 0.012) and CD79a expression (p = 0.012), but less frequent light chain restriction (p = 0.029). Using fluorescence in situ hybridization, we identified 13q14 deletion, MYC rearrangement, and CCND1 rearrangement in 74%, 30%, and 5% cases, respectively, without any cases having rearranged BCL6 or IGH::FGFR3 fusion. In the 15 cases with adequate tissue for whole exome sequencing, the most frequent recurrent mutations were STAT3 (40%), NRAS (27%), and KRAS (20%). In conclusion, most PBL cases in Taiwan were HIV-unrelated. Around half of the cases were positive for EBV, with distinct clinicopathological features. Deletion of chromosome 13q14 was frequent. The PBL cases in Taiwan showed recurrent mutations involving JAK-STAT, RAS-MAPK, epigenetic regulation, and NOTCH signaling pathways, findings similar to that from the West.

Primary cutaneous gamma/delta T-cell lymphoma in Taiwan: A series of six cases with frequent solitary presentation and relatively indolent behavior

BACKGROUND

Primary cutaneous gamma/delta T-cell lymphoma (PCDG-TCL) is aggressive, frequently presenting as multiple plaques, tumors, and/or subcutaneous nodules.

METHODS

In this study, we conducted a retrospective study in a tertiary center in Taiwan to characterize this rare tumor.

RESULTS

We identified six patients. Five presented with a solitary lesion, including two with clinical impression of epidermal inclusion cyst or lipoma. Two of four evaluable cases exhibited epidermotropism, with one mimicking Pautrier microabscess. The neoplastic cells were pleomorphic and mostly medium- to large-sized. In all cases, the neoplastic cells expressed T-cell receptor (TCR)-γ and/or TCR-δ, with four co-expressing βF1. Two of these βF1+ cases co-expressed TCR-γ but not TCR-δ (two different clones). All were negative for Epstein-Barr virus (EBV), low stage, and treated with radiotherapy alone or combined chemotherapy and radiotherapy. In two patients, lymphoma relapsed in 3 and 7 months, respectively, and one patient died of the disease in 7 months. Four other patients were free of disease for 6 to 126 months.

CONCLUSION

PCGD-TCL cases in Taiwan are more commonly solitary, frequently with indolent courses. The two currently available TCR-δ clones alone might be insufficient to detect all tumors.

Lymphomatous effusion of monomorphic epitheliotropic intestinal T-cell lymphoma is characterized by azurophilic granules and is a dismal sign: Report of two new cases with literature review

Lymphoma involving serous effusion is uncommon. The diagnosis of effusion lymphoma may be challenging, particularly when the lymphoid cells are small to medium-sized, which would be difficult for differentiating reactive effusions from low grade lymphomas. Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is an uncommon type of aggressive intestinal T cell lymphoma with a median survival of 7 months. MEITL rarely disseminates to the body cavities. To date, there are only three reported cases of MEITL with malignant effusion. Here we report two additional cases of MEITL with lymphoma cells involving the pleural effusion and the ascites, respectively. Review of the three literature cases and our two new cases of MEITL with malignant effusion, cytoplasmic azurophilic granules were identified in both the two cases with Liu stain. The median survival time was 1.5 months after the occurrence of malignant effusion, even shorter than the median survival in patients with MEITL. Although the case number is small, malignant effusion seems to be a poor prognostic factor of MEITL.

MYD88 L265P mutation analysis is a useful diagnostic adjunct for lymphoplasmacytic lymphoma with pleural effusion

Lymphoplasmacytic lymphoma (LPL) is a marrow-based lymphoma, rarely involving extramedullary sites, particularly the pleural cavities. The distinction of lymphomatous pleural effusion (PE) in LPL patients from benign effusion is challenging. We conducted this study to examine whether MYD88 L265P mutation analysis is useful in distinguishing benign from lymphomatous PE in four patients with LPL, in which the initial marrow specimens were all positive for MYD88 mutation. In one case each with plasma cell- or lymphocyte-predominant PE, MYD88 mutation was positive, confirming lymphomatous effusion. The other lymphocyte-predominant PE was negative for MYD88 mutation, but was clonally related to a previous nodal biopsy and this PE was also considered to have LPL involvement. The fourth case developed large B-cell lymphoma in the PE 30 months later. The PE specimen was negative for MYD88 mutation but was clonally related to the diagnostic marrow tissue, indicating large cell transformation. Four cases of small lymphocyte-predominant benign PE from patients without history of lymphoma were examined and were all negative for MYD88 L265P mutation. In conclusion, in this small case series we showed that MYD88 L265P mutation analysis could serve as a useful adjunct in distinguishing benign from lymphomatous PE in patients with LPL.

Primary effusion lymphoma in Taiwan shows two distinctive clinicopathological subtypes with rare human immunodeficiency virus association

AIMS

To investigate the clinicopathological and molecular features of primary effusion lymphoma (PEL) in Taiwan and the association with human immunodeficiency virus (HIV), human herpesvirus 8 (HHV8) and Epstein-Barr virus (EBV).

METHODS AND RESULTS

We investigated retrospectively 26 cases with a median age of 76.5. Only one (4%) patient was infected with HIV. Cytologically, all lymphoma cells revealed typical immunoblastic to plasmablastic morphology. Immunohistochemically, HHV8 was positive in eight (32%) tumours and negative in 17 (68%) cases. All 23 tested cases examined were of the non-germinal-centre B cell phenotype. MYC proto-oncogene (MYC) and Epstein-Barr encoding mRNA (EBER) were positive in 43% (nine of 21) and 17% (four of 23) cases, respectively. Immunoglobulin heavy chain (IGH), B cell lymphoma (BCL)2, BCL6 and MYC were rearranged in 71%, 11%, 12% and 18% cases, respectively. By univariate analysis, the overall survival (OS) was associated statistically with MYC expression (P = 0.012) and BCL2 rearrangement (P = 0.035), but not with the others. By multivariate analysis, no factor was statistically significant. Compared to the HHV8-negative cases, the HHV8-positive cases were mainly of the plasmablastic immunophenotype expressing CD30 and CD138, and with a less frequent expression of pan-B cell markers.

CONCLUSIONS

Apart from the phenotypical difference, our HHV8-positive neoplasms were not distinct from the HHV8-negative group. Literature review of 256 cases, including our cases, revealed that HHV8-positive cases were associated more frequently with HIV and EBV infection, with rare MYC rearrangement, and a poorer prognosis than HHV8-negative cases. We propose to name the HHV8-positive cases as 'classical' or 'type I PEL' and the HHV8-negative cases as 'type II PEL', stressing the similarities and the distinctive features between these two groups.

Evaluation of PIMA point-of-care CD4 analyzer in Yunnan, China

Background:

CD4 count is used to determine antiretroviral therapy (ART) eligibility. In China, flow cytometers are mostly located in urban areas with limited access by patients residing in remote areas. In an attempt to address this issue, we conducted a study to validate the performance of Alere PIMA point-of-care CD4 analyzer.

Methods:

Venous and finger-prick blood specimens were collected from HIV-positive participants from two voluntary counseling and testing sites in Yunnan Province. Both venous and finger-prick blood specimens were tested with the PIMA analyzer. Venous blood specimens tested with the Becton Dickinson FACSCalibur were used as a reference.

Results:

Venous specimens from 396 and finger-prick specimens from 387 persons were available for analysis. CD4 counts by PIMA correlated well with those from FACSCalibur with an R² of 0.91 for venous blood and 0.81 for finger-prick blood. Compared to FACSCalibur, the PIMA analyzer yielded lower counts with a mean bias of − 47.0 cells/μl (limit of agreement, [LOA]: −204–110 cells/μl) for venous blood and −71.0 cells/μl (LOA: −295–153 cells/μl) for finger-prick blood. For a CD4 threshold of 350 cells/μl, the positive predictive value (PPV) of PIMA was 84.2% and 75.7% and the negative predictive value (NPV) was 97.6% and 95.8% for venous and finger-prick blood, respectively. For an ART threshold of 500 cells/μl, the corresponding PPV was 90.3% and 84.0% and NPV was 94.3% and 93.4%, respectively.

Conclusions:

CD4 counting using venous blood with PIMA analyzers is a feasible alternative to a large flow cytometer to determine ART eligibility.

Effects of changes in serum endostatin and fibroblast growth factor 19 on the chemotherapeutic sensitivity in acute myeloid leukemia patients

The present study aimed to explore the changes in serum endostatin and fibroblast growth factor 19 (FGF-19) in acute myeloid leukemia patients, and to determine their effects on chemotherapeutic sensitivity. Sixty acute myeloid leukemia patients and 30 healthy controls were included in the study. Patient serum endostatin and FGF-19 levels were measured on admission, and then, standard chemotherapy was administered. The patients were divided into 2 groups according to chemotherapeutic effects: 21 patients in the chemotherapeutic sensitivity group (complete remission + partial remission) and 39 in the chemotherapeutic resistance group (no remission + degradation). A receiver operating characteristic (ROC) curve was used to analyze the relationship of serum endostatin and FGF-19 levels with chemotherapeutic sensitivity in acute myeloid leukemia patients. The levels of serum endostatin and FGF-19 in acute myeloid leukemia patients before chemotherapy were significantly higher than those in the control group. Moreover, these levels significantly decreased after chemotherapy (P < 0.01). The levels of serum endostatin and FGF-19 in the chemotherapeutic sensitivity group were lower than those in the chemotherapeutic resistance group, both before and after chemotherapy (P < 0.05 and P < 0.01, respectively). ROC curve analysis showed that the predictive values of endostatin and FGF-19 were good, and there was no significant difference between these results. In conclusion, serum endostatin and FGF-19 can be used as predictors of chemotherapeutic sensitivity for acute myeloid leukemia patients, and may be important for determining prognosis.

Angiopep-pluronic F127-conjugated superparamagnetic iron oxide nanoparticles as nanotheranostic agents for BBB targeting

Pluronic® F127-modified water-dispersible poly(acrylic acid)-bound iron oxide (PF127-PAAIO) nanoparticles have been prepared as diagnostic agents. A blood-brain-barrier penetrating peptide, angiopep-2 (ANG), was further conjugated onto the surface of the PF127-PAAIO (ANG-PF127-PAAIO) for brain targeting. The ANG-PF127-PAAIO shows negligible cell cytotoxicity, better cellular uptake, and higher T₂-weighted image enhancement than the PF127-PAAIO in U87 cells. Using an ex vivo blood-brain barrier (BBB) model, we showed that the ANG-PF127-PAAIO shows better permeability to bypass the BBB. This is because the ANG-PF127-PAAIO has a dual-targeting ability, recognition of the low-density lipoprotein receptor-related protein and clathrin-mediated receptor on the U87 surface. Thus, the ANG-PF127-PAAIO is a potential nanotheranostic agent for brain dysfunction.

Significance of SODD expression in childhood acute lymphoblastic leukemia and its influence on chemotherapy

This study explored the clinical significance of silencer of death domain (SODD) expression in childhood acute lymphoblastic leukemia (ALL) and its influence on chemotherapy as well as the effect of SODD expression on apoptosis of leukemic cells. The expression of SODD proteins in different ALL groups was determined by immunocytochemistry. The SODD RNAi-interfering plasmid was constructed and transferred to Jurkat cells, and the effects of SODD expression on cell proliferation and apoptosis were analyzed using the MTT and FCM methods. The expressions of SODD, Phospho-NF-κB-P65, Bcl-2, and Caspase 3 were detected by Western blot analysis. The expression of SODD proteins was significantly higher in the ALL groups than in the control group (P < 0.05). The positive expression rate of SODD was significantly higher in refractory/relapsed and clinical high-risk groups than in standard-risk, initial treatment, and complete remission groups (P < 0.05). Microtubule-targeting drugs such as vincristine and taxol can notably down-regulate SODD expression during apoptosis, whereas DNR, and Ara-c cannot. The sensitivity of Jurkat cells to chemotherapeutic drugs increased with down-regulated SODD expression induced by SODD-interfering plasmid transfection. The sensitivity of the cells transfected with SODD-cloning genes decreased. SODD expression was high in the ALL children. These findings indicated that SODD over-expression might be correlated with the clinical classification, curative effect, and prognosis of ALL cells. Microtubule-targeting drugs can specifically down-regulate SODD expression in leukemic cells, thereby increasing the sensitivity of leukemic cells to SODD-targeting chemotherapeutics. In contrast, increased SODD expression tends to reduce sensitivity.

Rapidly fatal leukemia comprising pleomorphic large granular lymphocytes: a report of 2 cases

BACKGROUND

Large granular lymphocytes (LGLs) are either cytotoxic T or natural killer (NK) cells exhibiting round nuclei and azurophilic cytoplasmic granules. Morphologically, neoplastic LGLs of T cell lineage (T-LGLLs) are usually indistinguishable from normal LGLs, while there is a wide morphological range of aggressive NK cell leukemia (ANKL).

CASES

We present 2 consecutive cases of leukemia comprising pleomorphic LGLs. One patient presented with drowsy consciousness and unstable hemodynamics. Her peripheral blood smear disclosed a significant number of LGLs with pleomorphic nuclei expressing CD2, CD56 and HLA-DR but not surface or cytoplasmic CD3 (cCD3). The second patient, previously healthy, presented with a sudden death. Her peripheral blood revealed LGLs ranging from round to pleomorphic nuclei with a CD2+ cCD3+ surface CD3- CD56+ phenotype and clonally rearranged T cell receptor gene. The findings of the first patient were consistent with ANKL and the second, T-LGLL. Both patients passed away shortly before treatment.

CONCLUSION

The 2 cases highlight the importance of a multidisciplinary approach in addition to cytological examination to reach accurate diagnoses of such rare leukemia cases.

[Estimation on the HIV-1 incidence among high risk groups using the pooling RNA technique]

OBJECTIVE

To timely identify the HIV-1 infection in window-period and to estimate the HIV-1 incidence among people who came for voluntary counseling and testing (VCT) service as well as men who have sex with men (MSM), respectively.

METHODS

HIV antibody negative samples that were determined by screening tests between January and October 2012, were collected and tested with pooling HIV-1 RNA testing technique (2-staged pooling by 50:1, 10:1). Positive cases were followed-up for HIV antibody testing while HIV incidence was calculated under Ron Brookmeyer' s method, among VCT and MSM populations.

RESULTS

Among 1400 HIV antibody negative samples of VCT, two showed HIV-1 RNA positive during the antibody window period with the HIV-1 incidence as 1.87% per year (95% CI: 1.23%-2.65% ). Among 500 HIV antibody negative samples from MSM population, two showed HIV-1 RNA positive in the antibody window period, with HIV-1 incidence as 5.31% per year (95% CI: 3.52%-7.45% ).

CONCLUSION

Pooling HIV-1 RNA testing seemed a powerful tool for HIV antibody testing in the window-period. Measures should be taken to strengthen the HIV diagnostic programs among MSM and other high risk groups,during the HIV antibody window-period. More frequent detection approach as pooling HIV-1 RNA testing might be a good choice.

Flavokawain B, a novel chalcone from Alpinia pricei Hayata with potent apoptotic activity: Involvement of ROS and GADD153 upstream of mitochondria-dependent apoptosis in HCT116 cells

Flavonoids synthesized from chalcone precursors in plants have been shown to possess cytotoxic activities with therapeutic potential. We have isolated the novel chalcone flavokawain B from Alpinia pricei Hayata, a plant native to Taiwan that is used in food and traditional Chinese medicine. Here, we report for the first time that flavokawain B significantly inhibits the growth of colon cancer cells and provide novel insight into the molecular mechanisms that underlie its apoptotic activity. Flavokawain B exerts its apoptotic action through ROS generation and GADD153 up-regulation, which lead to mitochondria-dependent apoptosis characterized by release of cytochrome c and translocation of Bak. The up-regulation of GADD153 in flavokawain B-treated HCT116 cells is associated with mitochondrial dysfunction and altered expression of Bcl-2 family members. Moreover, pretreatment with the ROS scavenger N-acetylcysteine abolishes flavokawain B-induced ROS generation, GADD153 up-regulation, and apoptosis. Similarly, RNAi-mediated gene silencing reduced flavokawain B-enhanced expression of GADD153 and apoptotic Bim, leading to diminished apoptosis. Interestingly, flavokawain B provokes G2/M accumulation as well as autophagy, in addition to apoptosis, suggesting that multiple pathways are activated in flavokawain B-mediated anticancer activity. Taken together, our data provide evidence for a molecular mechanism to explain the apoptotic activity of Alpinia plants, showing that flavokawain B acts through ROS generation and GADD153 up-regulation to regulate the expression of Bcl-2 family members, thereby inducing mitochondrial dysfunction and apoptosis in HCT116 cells.

Inhibition of cellular growth and induction of apoptosis in pituitary adenoma cell lines by the protein kinase C inhibitor hypericin: potential therapeutic application

Protein kinase C (PKC) is an enzyme involved in the regulation of cellular growth, proliferation, and differentiation in a number of tissues including the anterior pituitary, in which it is also believed to play a role in hormone secretion. Protein kinase C activity and expression have been found to be greater in adenomatous pituitary cells than in normal human and rat pituitary cells and higher in invasive pituitary tumor cells than in noninvasive ones. Inhibition of PKC activity has been shown in a variety of tumor cells to inhibit growth in a dose-related fashion. The purpose of the current study was to determine whether hypericin, a potent inhibitor of PKC activity that may be administered clinically, alters the growth and proliferation in established pituitary adenoma lines and to determine if inhibition of PKC activity induces apoptosis, as reported in some other tumor cell types. Two established pituitary adenoma cell lines, AtT-20 and GH4C1, were treated with hypericin in tissue culture for defined periods following passage. Inhibition of growth was found to be dose dependent in all three cell lines in low micromolar concentrations of hypericin, as determined by viable cell counts, methylthiotetrazole assay, and [3H]thymidine uptake studies. Concentrations of hypericin as low as 100 nM also induced apoptosis in these established lines, whereas treatment of normal human fibroblasts with a concentration of 10 microM failed to induce apoptosis. The potential use of hypericin in the therapy of pituitary adenomas warrants additional in vitro investigations with the aim of later moving toward therapeutic trials in selected patients in whom surgical or medical therapy has failed.

Distinct P-glycoprotein expression in two subclones simultaneously selected from a human colon carcinoma cell line by cis-diamminedichloroplatinum (II)

Two drug-resistant sublines, CP2.0 and RT, were simultaneously selected by cis-diamminedichloroplatinum (CDDP) from the human colon carcinoma cell line LoVo by the conventional method of continuous drug exposure. The 2 sublines differed in morphology, growth kinetics and pattern of gene expression. Genetic signature analysis indicated that the lines were independent subclones but that both arose from LoVo. These sublines were maintained in a growth medium containing 2.0 micrograms/ml CDDP. However, CP2.0 cells were 3 times more resistant to CDDP than were RT cells. Although both were cross-resistant to mustargen and 5-fluorouracil, only CP2.0 was resistant to Adriamycin and vincristine. Western-blot analysis, immunocytochemical staining and in vitro phosphorylation experiments indicated that the level of P-glycoprotein was significantly elevated in CP2.0 but not in RT. Despite the differences between these sublines, they possess similar CDDP-resistance mechanisms, including decreased intracellular CDDP accumulation, elevated levels of glutathione and metallothionein-like proteins, increased glutathione transferase-pi mRNA, and enhanced susceptibility to CDDP cytotoxicity after treatment with DL-buthionine-[S,R]-sulfoximine. Nevertheless, our results suggest that, in certain tumor types, P-glycoprotein-mediated multi-drug resistance and CDDP-resistance phenotypes can coexist in cells with primary resistance to CDDP.

2 chlorodeoxyadenosine activity and cross resistance patterns in primary cultures of human hematologic neoplasms

2-Chlorodeoxyadenosine (2-CDA) is an adenosine deaminase resistant analogue of deoxyadenosine which has shown clinical activity in human hematologic neoplasms. The exact mode of action of this drug remains the subject of investigation. We applied the Differential Staining Cytotoxicity (DiSC) assay to 50 human tumour specimens obtained from patients with a variety of hematologic malignancies to characterise the activity spectrum of 2-CDA. We evaluated the disease-specific activity of this agent in vitro and compared its relative cytotoxicity with that of other antineoplastic agents in current clinical use. Comparisons were conducted against nitrogen mustard, doxorubicin, vincristine and cytosine arabinoside. Our results indicate that 2-CDA has activity in myeloid and many lymphoid neoplasms but that multiple myeloma specimens reveal significant resistance. Cross resistance studies reveal a correlation between 2-CDA and the alkylator nitrogen mustard but no correlation between 2-CDA and doxorubicin, vincristine nor cytosine arabinoside. The results suggest 2-CDA activity in many human hematologic neoplasms with the clear exception of multiple myeloma and further suggest a relationship between this agent and alkylators of the mustard class. The DiSC assay may provide useful insights in the pre-clinical evaluation of new antineoplastic drugs and may help to elucidate drug activities and mechanisms of action.

Further characterization of two distinct adriamycin-resistant sublines from LoVo human colon carcinoma cells

We previously reported that two multidrug resistant sublines, AdR1.2 and SRA1.2, derived from LoVo human colon carcinoma cells, apparently expressed different resistance phenotypes including differential expression of p-glycoprotein (Pgp). Here, we further examined and compared other potential resistance mechanisms between AdR1.2 and SRA1.2 resistant cells. Our results showed that the Pgp-mediated AdR1.2 cells possessed an activated drug efflux pump and decreased nucleus binding of Adriamycin, while the non-Pgp-mediated SRA1.2 cells only held the second feature. Verapamil, however, partially reversed resistance in both sublines. Although glutathione-s-transferase was overexpressed in AdR1.2 but not in SRA1.2, both sublines had lower susceptibilities to drug-induced DNA strand breaks and greater capacities to repair such damage than did LoVo cells. These data suggest that, despite the differences in multidrug resistance phenotypes, the features of decreased susceptibility to DNA damage and enhanced DNA repair capacities may represent the common mechanisms responsible for drug resistance in both Pgp- and non-Pgp-mediated multidrug resistant cells.

Heterogeneous effects of interferon on antitumor agents' cytotoxicities to human colon carcinoma cell lines

Six established human colon carcinoma cell lines that segregated into three groups with different degrees of differentiation were treated using three subclasses of interferons as single agents and in combination with either 5-fluorouracil, cis-platinum, or adriamycin. The cytotoxicities of the combination treatments were heterogeneous and did not relate to the cell's levels of differentiation. Our data suggest that the optimal combinations of interferons and chemotherapeutic agents are independent of the differentiation state of the colon cancer cells.

Metronidazole enhances the cytotoxic synergism produced by the combination of 1-beta-arabinofuranosylcytosine and cis-diamminedichloroplatinum

Metronidazole (MZ) was evaluated as a single agent or in combination with CDDP and araC for its cytotoxic effects on five established human colon carcinoma cell lines. MZ alone produced little cytotoxicity at 1 h drug incubation. The cytotoxicity was detectable only after 2 h incubation and increased as a function of duration of treatment, suggesting a time-dependent rather than a dose-dependent cytotoxic effect. MZ had no effect on CDDP- or araC-induced cytotoxicity, whereas MZ enhanced the synergism resulting from the combination of two antitumor agents on the human colon tumor cell lines tested. Such enhancement was more pronounced on cells growing in stationary rather than in exponential phase. MZ not only produced a reversible S-phase arrest but also lessened the CDDP-produced inhibition on the incorporation of araC into DNA. However, it did not enhance CDDP-induced DNA cross-linkings, with or without araC. Our results indicated that MZ enhanced the synergism produced by two antitumor drugs in combination and that enhancement was accompanied by an increase in S-phase population and of the incorporation of araC into nucleic acids.

Perturbation of in vitro drug resistance in human lymphatic neoplasms by combinations of putative inhibitors of protein kinase C

Fresh specimens of human lymphatic neoplasms were tested with the differential staining cytotoxicity assay. Cells from relapsed patients with acute lymphoblastic leukemia (ALL) were significantly more resistant to vincristine, dexamethasone, and doxorubicin in the assay than were cells from previously untreated patients. The putative C kinase inhibitors verapamil (V), imipramine (I), lidocaine (L), tamoxifen (T), chlorpromazine (C), and haloperidol (H) were then tested singly, in combination with each other (VILTCH, ITCH, and VL), and in combination with vincristine. At concentrations judged to be clinically achievable, VILTCH itself was occasionally toxic to ALL and chronic lymphocytic leukemia. The VILTCH combination clearly potentiated the cytotoxic activity of vincristine in five of eight ALL specimens from relapsed patients and potentiated vincristine in 18 of 30 chronic lymphocytic leukemia specimens. It also potentiated vincristine in two of six specimens of multiple myeloma and five of six specimens of non-Hodgkin's lymphoma. The VILTCH combination had no significant effects in fresh cultures of normal human lymphocytes. The most active drugs in the VILTCH combination appeared to be verapamil and lidocaine. We conclude that the differential staining cytotoxicity assay is a useful tool to study the circumvention of clinically acquired drug resistance. While the mechanism of the observed enhancement of the cytotoxic effects of vincristine is not known, it is possible that combinations of putative C kinase inhibitors may reduce drug resistance in human lymphatic neoplasms.

Selective enhancement by menadiol of in vitro drug activity in human lymphatic neoplasms

The effect of menadiol (vitamin K3) on fresh specimens of human lymphatic neoplasms (HLN) was tested by means of the differential staining cytotoxicity assay. Menadiol was tested alone and in combination with standard antineoplastic agents. Drug effects were then compared with the effects of the same drugs in normal human lymphocytes and in fresh specimens of human non-small cell lung cancer. By itself, menadiol was moderately toxic to HLN, but not to normal lymphocytes or non-small cell lung cancer. Menadiol, menadione, and two structurally related congeners were equitoxic to HLN cells, but sodium metabisulfite (present in menadiol solutions as a preservative) was nontoxic. Menadiol increased the cytotoxic effects of a number of standard agents in HLN but not in normal lymphocytes. Cell survival times with mechlorethamine, vincristine, and dexamethasone were converted from a range characteristic of drug resistance (ie, range observed in relapsed patients) to a range characteristic of drug sensitivity (ie, range observed in untreated patients) in the presence of menadiol. These effects occurred at a concentration (2.0 micrograms/ml; 4.7 microM) of menadiol which is probably clinically achievable and which did not deplete intracellular glutathione. Menadiol should receive clinical testing as a chemosensitizing agent in HLN.