Arthur E. Bogden

Chemotherapy responsiveness of human tumors as first transplant generation xenografts in the normal mouse: six-day subrenal capsule assay.

Feasibility of utilizing human tumors as first transplant generation xenografts in the normal immunocompetent mouse for determining tumor sensitivity to chemotherapeutic agents was demonstrated by applying subrenal capsule (SRC) assay methodology to fresh surgical explants in a six‐day time frame. A total of 37 human breast tumors were tested in assays in which 254 xenografts were implanted into control animals. Fifty (20%) of the controls showed some degree of partial regression in the six‐day assay period. Using a mean control growth having a positive change in tumor size as the criterion for evaluability, first transplant generation human breast tumors provided an evaluable assay rate of 86%. A tumor response profile was obtained as a result of testing seven clinically active drugs against 32 previously untreated breast cancers. The pattern of responses obtained indicated that no single agent was active against all tumors, nor were tumors which were responsive to one agent necessarily responsive to another, suggesting the feasibility of predicting individual tumor response to specific chemotherapeutic agents. Had these seven drugs been developmental agents of unknown activity which were being tested for the first time against such a panel of human tumors the results would have not only predicted their clinical activity, but the tumor response rates would have also provided an indication of the relative potential of each drug for the specific treatment of breast cancer.

Growth of Human Tumor Xenografts Implanted under the Renal Capsule of Normal Immunocompetent Mice

The subrenal capsule technique proved effective in demonstrating that the growth of human tumors in normal, immunocompetent animals for 6 days was quantifiable in ocular micrometer units. Positive growth was demonstrable not only with human tumors that had been established in serial transplantation in athymic nude mouse hosts, but also with primary surgical explants. Growth rates of transplantation-established xenograft systems were similar whether implanted in athymic nude or in normal immunocompetent animals indicating that the 6-day time-frame successfully evades growth inhibitory effects of immunologic origin. Immunosuppression with a single dose of cyclophosphamide did not appear to affect growth rate, but permitted the tumors to grow larger extending the time to reach peak size. Significantly, xenografts of primary surgical explants showed positive growth more frequently in 6 days (82%) in the immunocompetent animal than in 11 days (30%) in the immunodeficient athymic nude mouse.

Initial clinical trials of the subrenal capsule assay as a predictor of tumor response to chemotherapy

Retrospective and prospective clinical trials were performed to determine the usefulness of the 6‐day subrenal capsule (SRC) assay for the prediction of response to chemotherapy. Evaluable assays were obtained in 86% of 1000 consecutive specimens obtained from a variety of solid malignancies. Analysis of chemotherapeutic sensitivity in this assay gave reproducible and consistent results. The overall predictive accuracy of the assay in 62 retrospective clinical trials in 55 patients was 85%. Of 37 evaluable patients with chemotherapy refractory cancers treated in a prospective trial with single agent chemotherapy as determined by the assay, 14 (38%) responded. Greater degrees of tumor regression in the assay were associated with a higher probability of clinical response. The SRC assay shows potential value as a rapid predictive test for chemotherapeutic selection on an individual patient basis. However, additional prospective clinical trials are necessary to document its ultimate utility. Cancer 52:2185‐2192, 1983.

Immunological deficiency associated with cigarette smoke inhalation by mice. Primary and secondary hemagglutinin response.

Inhalation of cigarette whole smoke (CWS) or its vapor phase (CVP) significantly impaired immune response capability in mice. Significant immunosuppressive effects on the humoral antibody response to a single antigenic stimulus were evident in animals exposed to smoke for seven days before or two days after administration of antigen. Impairment of the immunological response capability appeared to be temporary, with recovery about 14 days after exposure. Different lengths of exposure prior to antigenic stimulation neither produced an additive impairment of the immunological response nor rendered the experimental animals more tolerant to CWS or CVP. The immunological deficiency was specific to CWS and CVP inhalation rather than to nonspecific debilitating stress factors. The inductive phase was the period of the primary and secondary immune response most sensitive to impairment by exposure to CWS or CVP.

Goralatide (AcSDKP), a negative growth regulator, protects the stem cell compartment during chemotherapy, enhancing the myelopoietic response to GM-CSF.

The aim of our study was to investigate the protection afforded to the bone marrow by Goralatide (AcSDKP), an inhibitor of hemopoietic stem cell proliferation, when administered alone or in combination with a growth factor (granulocyte/macrophage colony‐stimulating factor [GM‐CSF]) during iterative cycles of Ara‐C (cytarabine) treatment. In control mice receiving the inhibitor alone without Ara‐C, the number of granulocytes was reduced during treatment, and a surge in number of peripheral blood cells was observed after its completion. Peripheral hematological responses were monitored during 3 consecutive cycles of Ara‐C chemotherapy and the resultant nadir and recoveries. Analysis of variance of the treatment effects pooled over the 3 cycles showed that a treatment regimen in which the inhibitor was administered during the myelotoxic periods of chemotherapy confirmed the existence of a surge after completion of administration of the inhibitor and showed a significant protective effect. When the cycles of chemotherapy plus Goralatide were followed by GM‐CSF, the recovery from leukopenic nadirs was accelerated and the white blood cells and granulocyte levels were markedly increased over those observed in control mice and in mice treated either with Goralatide alone or with GM‐CSF alone. The differences were highly significant. A consistent and significant increase (p < 0.001) in platelet count was also noted in animals given Goralatide in conjunction with Ara‐C or Ara‐C + GM‐CSF. After three treatment cycles, this response to the CSF was far better in mice treated by the inhibitor than when CSF was given alone, suggesting a protection of the stem cell pool. Int. J. Cancer76:38–46, 1998.© 1998 Wiley‐Liss, Inc.

Specific and Nonspecific Immune Resistance Enhancing Activity of Staphage Lysate

The immunopotentiating activity of staphage lysate (SPL) was evaluated in terms of its immune protection against lethal bacterial infection and its antitumor activity. Mice were pretreated weekly with 10(8) viable, Staphylococcus aureus, strain 18Z for 3 weeks (Induction), followed by intraperitoneal SPL injections (Elicitation) at various times in relation to infectious challenge or tumor implantation. Induction without elicitation, or elicitation alone failed to provide protection against Klebsiella pneumoniae infection and resulted in only 30-40% survival against homologous infection with pathogenic S. aureus type III, whereas combined induction and elicitation produced enhanced resistance induction and elicitation regimens resulted in 50% and 80-100% survival in mice inoculated with K. pneumoniae and S. aureus, respectively. SPL had no antitumor effect in mice implanted with median survival time resulting from induction and elicitation in animals implanted which Ehrlichs ascites. This enhancement of immune resistance may possibly be related to activation of thymus-modulated lymphocytes and macrophages by SPL.

Activity of two phase I drugs N-methylformamide (NSC-3051) and Echinomycin (NSC-526417) against fresh surgical explants of human tumors in the 6-day subrenal capsule (SRC) assay

SummaryThe potential clinical activity of the new phase I drugs N-methylformamide (N-MF) and Echinomycin (ECH) was examined while still undergoing clinical toxicology trials by testing against fresh surgical explants of human tumors in the 6-day in vivo SRC Assay. Sixty-nine tumors representing different histologic types including breast, lung, colon, ovarian, and cervical, as well as neoplasms of undiagnosed origin, were screened against N-MF (NSC-3051) and ECH (NSC-526417) simultaneously with five standard chemotherapeutic agents used clinically for treatment of the specific type of cancer. Thus, activity of N-MF and ECH could be compared directly with that of standard agents tested in the same assay. Treatment schedule was QD1-5, and the criterion for drug activity was tumor graft regression > 20%. N-MF was active against 15/69 tumors with a response rate of 22%. ECH was also active against 15/69 tumors, yielding the same response rate. Although the response rates for N-MF and ECH were the same, indicating a similar degree of general anti-tumor activity as evaluated by the assay, N-MF showed greatest activity against lung tumors whereas ECH was more active against ovarian tumors. Twenty-six of 69 tumors (38%) were unresponsive to all drugs tested, only one tumor was responsive to both N-MF and ECH and no tumors were responsive to either N-MF or ECH alone. Cytoxan, one of the standard agents tested concurrently with both phase I drugs yielded a response rate of 35%, one and one-half times greater. Cervical and renal cancers and lymphomas were relatively unresponsive to both drugs.

Effects of hysterectomy on milk secretion and serum levels of prolactin, growth hormone, estrogen, and progesterone in rhesus monkeys with hormone-induced uterine hypertrophy☆

Abstract Lactation and uterine hypertrophy were induced and maintained in 5 nonpregnant female rhesus monkeys by exogenous estradiol-17β (E 2 ) and progesterone (P). Hypertrophic uteri were then removed surgically. Quantitation of weekly milk secretion and radioimmunoassays of serum estrone (E 1 ), E 2 , P, prolactin, and growth hormone (GH) were carried out from the fifth week prior to hysterectomy and through the eighth week after hysterectomy. The effects of hysterectomy were studied by comparing the serum hormonal levels and milk secretion of the posthysterectomy period with those of the prehysterectomy period. Following removal of the hypertrophic uteri, milk secretion increased from 266 ± 38 to 400 ± 37 mg.; serum levels of E 1 increased from 0.20 ± 0.01 to 0.41 ± 0.02 ng. per milliliter, and E 2 increased from 1.40 ± 0.09 to 1.78 ± 0.12 ng. per milliliter. Slight decreases were observed in serum levels of P (from 36.6 ± 7.6 to 32.3 ± 2.7 ng. per milliliter), prolactin (from 12.3 ± 1.5 to 9.4 ± 1.0 ng. per milliliter), and GH (from 28.8 ± 3.8 to 27.2 ± 6.2 ng. per milliliter.) These decreases were statistically not significant. The increased mammary secretory activity was correlated with the increased levels of circulating estrogen following hysterectomy. Such increase indicates significant competition for estrogen between the uterus and mammary glands.

Variation in serum hormone concentrations in different rat strains.

Summary Serum insulin, growth hormone and thyroxine levels were determined in rats of five inbred strains and one out-bred stock. Insulin levels were higher in the Wistar-Lewis/MAI than all other rat strains. Growth hormone was significantly increased in ARS-SD:SPF(SD) and Wistar-Lewis/MAI rats. All rats demonstrated low serum thyroxine levels in the range of 19.1-44.2 ng/ml. Higher insulin and growth hormone levels were attributed to the increase in body wt.

Chemotherapy responsiveness of human breast tumors in the 6-day subrenal capsule assay: An update

SummaryFeasibility of utilizing the 6-day subrenal capsule (SRC) assay to screen drugs against fresh surgical explants of human tumors was confirmed by testing six clinically active chemotherapeutic agents against 141 human breast cancers. Response rates of the six drugs obtained in the assay compared favorably with clinical response rates for the same drugs as reported by Carter (5). The evaluable assay rate for breast tumors was 92% as compared to 89% for gynecologic tumors. Innate drug resistance was indicated with 16 of 57 tumors (28%) which did not respond to any of the six agents tested. Differences in responsiveness of tumors to each agent in a potential three-drug combination of either CMF or CAF suggest that the effectiveness of multiagent therapy might be enhanced if the individual agents of a potential drug combination were selected on the basis of tumor sensitivity to each of the agents in a predictive assay. Although cross-resistance between L-PAM and cytoxan was demonstrated and was statistically significant, 31% of these tumors responded individually to either one or the other agent, suggesting caution in extrapolating concomitance in activity between these two alkylators.