Lewis M. Slater

Cyclosporin A reverses vincristine and daunorubicin resistance in acute lymphatic leukemia in vitro.

The development of drug resistance by tumor cells is a major obstacle to the cure of human malignancy. Cyclosporin A (CsA) completely reverses primary resistance to vincristine and cross resistance to daunorubicin in a pleiotropic drug-resistant subline of human T cell acute lymphatic leukemia. This subline is over 50-fold resistant to vincristine and fivefold resistant to daunorubicin. CsA has little effect on vincristine or daunorubicin activity in drug-sensitive parental leukemia and corrects daunorubicin resistance without altering cellular daunorubicin accumulation.

Systemic treatment of AIDS-related kaposi's sarcoma: Results of a randomized trial

PURPOSE Patients with acquired immunodeficiency syndrome (AIDS)-related epidemic Kaposis sarcoma generally respond well to cytotoxic chemotherapy. However, due to the associated myelosuppression, these patients are at risk for developing complicating infections that may affect survival. We therefore conducted a multi-center randomized clinical trial comparing single-agent against combination chemotherapy in advanced AIDS-related Kaposis sarcoma. Low-dose chemotherapy was employed to evaluate its role in combination therapy for this disease and the toxicities associated with the lower intensity. PATIENTS AND METHODS Sixty-one patients with extensive mucocutaneous Kaposis sarcoma or visceral involvement were randomized for treatment with low-dose Adriamycin (doxorubicin, 20 mg/m2) alone (31 cases) or in combination with bleomycin and vincristine (ABV) (30 cases). Patients were randomized within strata based on prognostic features associated with shorter survival in prior studies. Both treatment arms were evenly matched at study entry. RESULTS Complete and partial tumor remissions were significantly higher with ABV (88%) than with Adriamycin alone (48%) (p = 0.004). The median survival was 9 months in both groups. Study entry criteria significantly associated with shorter survival included CD4 lymphocyte counts less than 100/mm3, hemoglobin level less than 10 g/dL, a history of constitutional symptoms, and a prior history of opportunistic infection(s). Toxicities were similar in both arms, and the regimens were well tolerated. Neutropenia (granulocyte count less than 1,000/mm3) occurred in 34% of patients receiving Adriamycin alone and in 52% of patients receiving ABV and was progressive in successive courses of chemotherapy in both treatment arms. The development of AIDS-defined opportunistic infections was relatively infrequent during therapy (14%). CONCLUSIONS Low-dose ABV is an effective chemotherapy regimen for the treatment of extensive Kaposis sarcoma. ABV chemotherapy is associated with significantly higher responses than Adriamycin alone and with acceptable toxicity.

Verapamil Restoration of Daunorubicin Responsiveness in Daunorubicin-resistant Ehrlich Ascites Carcinoma

We have studied the influence of verapamil hydrochloride on the in vitro and in vivo effects of daunorubicin in Ehrlich ascites carcinoma. Daunorubicin-sensitive tumor was rendered resistant to daunorubicin by the continuous treatment of sequential generations of tumor-bearing BALB/c mice. The ability of daunorubicin to inhibit [(3)H]uridine and [(3)H]thymidine incorporation and the effect of daunorubicin on the mean survival time of host animals bearing daunorubicin-sensitive and daunorubicin-resistant Ehrlich ascites carcinoma were compared. The addition of verapamil to daunorubicin in vitro reduced the concentration of daunorubicin required to inhibit 50% of DNA and RNA synthesis in the daunorubicin-resistant tumor to that required in the daunorubicin-sensitive tumor, from 6 and 4.4 mug/ml to 1.5 and 1.3 mug/ml, respectively. Verapamil also restored drug sensitivity to daunorubicin-resistant Ehrlich ascites carcinoma in vivo. The 21.7+/-0.7 d mean survival time (MST) of BALB/c mice bearing daunorubicin-resistant tumor treated with daunorubicin alone rose to 44.0+/-0.7 d when the same tumor was treated with verapamil and daunorubicin, P < 0.001. This in vivo effect is specific for daunorubicin-resistant Ehrlich ascites carcinoma, since there is no alteration in MST of BALB/c mice bearing daunorubicin-sensitive or daunorubicin-resistant tumor when they are treated with verapamil alone or when BALB/c mice bearing daunorubicin-sensitive tumor are treated with daunorubicin and verapamil.

Successful pregnancy during chemotherapy for acute leukemia

A 26‐year‐old patient with acute lymphatic leukemia conceived while on systemic chemotherapy. This patient experienced relapse during the second trimester, and a second complete hematologic remission was achieved with doxorubicin hydrochloride, vincristine, and prednisone. A 2400‐gram, but otherwise normal, male infant was delivered by Caesarean section during the 36th gestational week. Growth and development of this child is normal at six months. Cancer 47:845–846, 1981.

Verapamil potentiation of VP-16-213 in acute lymphatic leukemia and reversal of pleiotropic drug resistance

SummaryVerapamil, the calcium-influx-blocking agent, has previously been shown to have favorable interactions with antineoplastic drugs. Our study of human T cell acute lymphatic leukemia (ALL) GM3639 indicates that verapamil enhances the in vitro cytotoxicity of VP-16-213 against drug-sensitive ALL by reducing the concentration of VP-16-213, resulting in 50% cell viability from 104.5±26.6 nM to 46.0±2.7 nM (P<0.05). The addition of verapamil to VP-16-213 treatment of BDF/1 mice bearing L1210 leukemia increases their mean survival from 21.2±3.6 to 50.4±4.3 days (P<0.01) and the survival of CD2F/1 mice bearing P388 leukemia from 27.8±3.7 to 49.1±5.0 days (P<0.01). The 30-day survival is significantly increased in L1210 and P388 leukemia mice, and 60-day survival is significantly increased in P388 leukemic mice by verapamil.We developed a vincristine (VCR)-resistant subline of GM3639 T cell ALL, L23, by continuous exposure of drug-sensitive cells to VCR. This subline demonstrates pleiotropic cross resistance to VP-16-213 and daunorubicin. The addition of verapamil to VCR, to VP-16-213, and to daunorubicin completely restores responsiveness to these drugs, as indicated by the normalization of the VCR and VP-16-213 concentrations required for cytotoxicity and the concentration of daunorubicin required for inhibition of thymidine incorporation.

Combined interferon-antimetabolite therapy of murine L1210 leukemia

To assess the interaction of interferon with established chemotherapeutic agents, L1210 murine leukemia in BDF/1 mice was treated with methotrexate, 6‐mercaptopurine, Adriamycin, cytosine arabinoside or cyclophosphamide alone or in combination with mouse L‐cell (Newcastle disease virus‐induced) interferon or with interferon‐free tissue culture medium. Also studied was the effect of interferon on the combined 6‐mercaptopurine‐methotrexate therapy of this tumor. Interferon failed to enhance the response of L1210 leukemia to 6‐mercaptopurine, adriamycin, cytosine arabinoside or cyclophosphamide. The addition of interferon to all methotrexate‐containing regimens increased mean survival time (P < 0.05). The increase in survival of host animals treated with 6‐mercaptopurine‐methotrexate and interferon was sustained through four transfer generations despite evolving resistance to this antimetabolite combination.

In vivo and in vitro cell-mediated immunity to tetanus toxoid in adults

The purpose of this study was to evaluate tetanus toxoid (TT) as an indicator of cutaneous delayed hypersensitivity (CDH) in adults. Fifty-two normal subjects, aged 25 to 64 yr, were skin tested with TT and streptokinase-streptodornase (SK/SD). Lymphocyte transformation was studied in seven normal TT reactors, four normal TT nonreactors, and seven hospitalized anergic patients. CDH was common with both TT and SK/SD; 90% of the adults, aged 25 to 39 yr, had CDH reactions to TT and 79% had CDH reactions to SK/SD. In adults aged 40 to 64 yr, 75% had DCH reactions to TT and 59% had CDH reactions to SK/SD. Lymphocyte transformation to TT correlated well with TT skin-test results. Punch biopsy specimens of TT reactions 48 hr after skin testing demonstrated DCH. We conclude that TT is an excellent antigen for assessing the presence or absence of CDH in adults aged 25 to 64 yr.

Mondor's disease associated with metastatic axillary nodes.

Mondors disease, superficial thrombophlebitis of the breast, is customarily associated with benign conditions of the breast. This article reports a patient in whom an early manifestation of recurrent axillary metastasis from carcinoma of the breast was a symptom of ipsilateral superficial thrombophlebitis of the breast, an unusual association.

Tumor apoptosis induced by epoxide-containing piperazines, a new class of anti-cancer agents

Purpose: The overall purpose of this study was to determine the potential efficacy of epoxide-containing piperazines as a new class of anti-cancer agents. Two representative compounds, specifically NCO-700, a 4-trimethoxyphenyl-substituted epoxide-piperazine, and TOP-008, a 4-phenylpropenyl-substituted epoxide-piperazine were tested in cytotoxic assays with human breast and prostate cancer cell lines. A second objective was to determine if these two compounds had anti-cancer activity in vivo when tested against xenograft tumors in nude mice or human tumors grown under the kidney capsule in mice. A final objective of this study was to establish if NCO-700 and TOP-008 achieved cancer cell killing through an apoptotic mechanism. Methods: The anti-proliferative activity of NCO-700 and TOP-008 were tested in a 7 day cell-survival assay utilizing a number of well characterized breast (HS-578T, T47D, MCF-7) and prostate (DU-145, PC-3, LNCaP) cancer cell lines. In vivo studies with the two compounds were performed, in nude mice bearing DU-145 xenograft tumors, and in normal mice in which DU-145 prostate cancer cells and HS-578T breast cancer cells were grown as solid tumors in the subrenal capsules of the animals. Apoptotic cell death of cancer cells was determined by a number of established techniques that detect apoptosis, including the confocal laser microscopy of treated cells and mitochondrial leakage assays utilizing the cationic dye, JC-1. Finally, the activation of the caspase cascade, enzymes that carry out apoptosis in mammalian cells, was examined in treated cells by immunoblot assays. Results: NCO-700 and TOP-008 displayed cytotoxicity to HS-578T human breast cancer cells, with ED50 values in the 3–6 μM range. Cytotoxicity to androgen receptor-negative human prostate cancer cells (PC-3 and DU-145 cells) occurred with ED50 values in the 5–20 μM range. Cytotoxicity to hormone receptor-positive breast and prostate cancer cell lines occurred at 10 to 20-fold higher concentrations of the two compounds. When human prostate (DU-145) or breast cancer (HS-578T) cells were grown as solid tumors in the subrenal capsules of mice, significant anti-tumor activity of NCO-700 was observed at 20 mg/kg and 50 mg/kg body weight respectively, for prostate and breast tumors. In nude mice bearing DU-145 prostate tumor xenografts, 50 mg/kg doses of the two compounds either stopped (TOP-008) tumor growth or slowed (NCO-700) growth. The mechanism of cytotoxicity was shown to be through apoptosis, (a) by confocal microscopy studies revealing nuclear fragmentation, (b) by mitochondrial studies revealing disruption of the mitochondrial membrane and release of the cationic dye, JC-1, into the cytoplasm and (c) by protein immunoblot assays indicating that over a 6 h period, TOP-008 induced a significant accumulation of the pro-apoptotic protein, bak, in the mitochondrial fraction of HS-578T human breast cancer cells, accompanied by activation, at 2.5 h, of caspase-3. Conclusions: These studies indicated that the epoxide-containing piperazines, as exemplified by NCO-700 and TOP-008, were effective anti-cancer agents when tested in vitro and in vivo against human breast and prostate tumors. Our studies also indicated that TOP-008 induced the initiation of the caspase cascade leading to apoptosis. Previous toxicology studies in rodents and dogs, as well as a Phase I study in humans, showed NCO-700 to be a well-tolerated, non-toxic compound. Taken together with our current findings, these results suggest that this class of compounds has the potential to be relatively safe, new chemotherapeutic agents for refractory breast and prostate cancers.

Correction of altered plasma membrane potentials

SummaryWe have recently shown that cyclosporin A (CsA) reverses pleiotropic drug resistance in human acute lymphatic leukemia in vitro and daunorubicin resistance in Ehlrich ascites tumor in vivo. In the present study we examined the mechanisms by which CsA might reverse pleiotropic drug resistance relative to changes in cellular plasma membrane potentials and intracellular calcium ([Ca2+]i). Membrane potentials were measured with DIOC5 dye flowcytometrically and [Ca2+]i levels with Quin 2 dye spectrofluorimetrically. All pleiotropic (PDR) drug-resistant tumor sublines had decreased membrane potentials (membrane depolarized) compared with their corresponding drug-sensitive parental tumors. In comparison, the membrane potentials of a control antimetaboliteresistant acute leukemia cell line were unchanged. The basal levels of [Ca2+]i in the PDR sublines were variable compared with those of parental drug-sensitive cell lines. Incubation of all PDR tumor sublines with CsA or verapamil resulted in the restoration of membrane potentials to that characteristic of the corresponding drug-sensitive parental tumor. Cyclosporin A produced variable changes in the levels of [Ca2+]i. These data suggest that alteration of membrane potentials is one of the mechanisms responsible for pleiotropic drug resistance in malignancy and show that this alteration is corrected by CsA and verapamil.