An Antibody Targeting ICOS Increases Intratumoral Cytotoxic to Regulatory T-cell Ratio and Induces Tumor Regression

The immunosuppressive tumor microenvironment constitutes a significant hurdle to immune checkpoint inhibitor responses. Both soluble factors and specialized immune cells, such as regulatory T cells (Treg), are key components of active intratumoral immunosuppression. Inducible costimulatory receptor (ICOS) can be highly expressed in the tumor microenvironment, especially on immunosuppressive Treg, suggesting that it represents a relevant target for preferential depletion of these cells. Here, we performed immune profiling of samples from tumor-bearing mice and patients with cancer to demonstrate differential expression of ICOS in immune T-cell subsets in different tissues. ICOS expression was higher on intratumoral Treg than on effector CD8 T cells. In addition, by immunizing an Icos knockout transgenic mouse line expressing antibodies with human variable domains, we selected a fully human IgG1 antibody called KY1044 that bound ICOS from different species. We showed that KY1044 induced sustained depletion of ICOS^high T cells but was also associated with increased secretion of proinflammatory cytokines from ICOS^low effector T cells (T_eff). In syngeneic mouse tumor models, KY1044 depleted ICOS^high Treg and increased the intratumoral T_Eff:Treg ratio, resulting in increased secretion of IFNγ and TNFα by T_Eff cells. KY1044 demonstrated monotherapy antitumor efficacy and improved anti-PD-L1 efficacy. In summary, we demonstrated that using KY1044, one can exploit the differential expression of ICOS on T-cell subtypes to improve the intratumoral immune contexture and restore an antitumor immune response.

Fulvestrant Plus Vistusertib vs Fulvestrant Plus Everolimus vs Fulvestrant Alone for Women With Hormone Receptor-Positive Metastatic Breast Cancer: The MANTA Phase 2 Randomized Clinical Trial

Question

Does the addition of vistusertib increase progression-free survival and other measures of antitumor activity of fulvestrant in postmenopausal women with estrogen receptor–positive advanced or metastatic breast cancer that progressed after prior therapy with aromatase inhibitors?

Findings

This randomized clinical trial in 333 patients failed to demonstrate a benefit of vistusertib plus fulvestrant vs fulvestrant alone. In addition, the outcomes in both vistusertib groups were inferior to those in the group treated with fulvestrant plus everolimus.

Meaning

The results suggest that dual mammalian target of rapamycin inhibition with vistusertib at the maximal tolerated doses is inferior to mammalian target of rapamycin complex 1 inhibition with the rapamycin analogue everolimus.

Importance

Randomized clinical trials have demonstrated a substantial benefit of adding everolimus to endocrine therapy. Everolimus inhibits the mammalian target of rapamycin complex 1 (mTORC1) complex but not mTORC2, which can set off an activating feedback loop via mTORC2. Vistusertib, a dual inhibitor of mTORC1 and mTORC2, has demonstrated broad activity in preclinical breast cancer models, showing superior activity to everolimus.

Objective

To evaluate the safety and efficacy of vistusertib in combination with fulvestrant compared with fulvestrant alone or fulvestrant plus everolimus in postmenopausal women with estrogen receptor–positive advanced or metastatic breast cancer.

Design, Setting, and Participants

The MANTA trial is an open-label, phase 2 randomized clinical trial in which 333 patients with estrogen receptor–positive breast cancer progressing after prior aromatase inhibitor treatment underwent randomization (2:3:3:2) between April 1, 2014, and October 24, 2016, at 88 sites in 9 countries: 67 patients were assigned to receive fulvestrant, 103 fulvestrant plus vistusertib daily, 98 fulvestrant plus vistusertib intermittently, and 65 fulvestrant plus everolimus. Treatment was continued until disease progression, development of unacceptable toxic effects, or withdrawal of consent. Analysis was performed on an intention-to-treat basis.

Interventions

Fulvestrant alone or in combination with vistusertib (continuous or intermittent dosing schedules) or everolimus.

Main Outcomes and Measures

The primary end point was progression-free survival (PFS).

Results

Among the 333 women in the study (median age, 63 years [range, 56-70 years]), median PFS was 5.4 months (95% CI, 3.5-9.2 months) with fulvestrant, 7.6 months (95% CI, 5.9-9.4 months) with fulvestrant plus daily vistusertib, 8.0 months (95% CI, 5.6-9.9 months) with fulvestrant plus intermittent vistusertib, and 12.3 months (95% CI, 7.7-15.7 months) with fulvestrant plus everolimus. There was no significant difference in PFS between those receiving fulvestrant plus daily or intermittent vistusertib and fulvestrant alone (hazard ratio, 0.88 [95% CI, 0.63-1.24]; P = .46; and hazard ratio, 0.79 [95% CI, 0.55-1.12]; P = .16).

Conclusions and Relevance

The combination of fulvestrant plus everolimus demonstrated significantly longer PFS compared with fulvestrant plus vistusertib or fulvestrant alone. The trial failed to demonstrate a benefit of adding the dual mTORC1 and mTORC2 inhibitor vistusertib to fulvestrant.

Trial Registration

ClinicalTrials.gov identifier: NCT02216786 and EudraCT number: 2013-002403-34

A first-in-human study of KY1044, a fully human anti-ICOS IgG1 antibody as monotherapy and in combination with atezolizumab in patients with selected advanced malignancies

TPS2644

Background: The Inducible T-cell costimulator (ICOS/CD278) is related to the CD28 superfamily and is induced upon T cell activation. There is a hierarchical order of ICOS expression level, in which highly immunosuppressive TReg (CD4+Foxp3+) present in the tumor microenvironment (TME) are at the top level of expression and CD8 TEff cells are at the bottom level. In addition, ICOS expression on TRegs is higher in the TME than in the blood or spleen. Methods: KY1044, a fully human anti-ICOS IgG1 kappa monoclonal antibody, selectively binds to ICOS with high affinity (which is maintained at intratumoral acidic pH) and has a dual mechanism of action: it promotes the preferential depletion of intratumoral ICOSHigh TRegs resulting in an increase in the TEff:TReg ratio in the TME; and it stimulates ICOSLow TEff cells. Preclinical data demonstrate that KY1044 monotherapy or in combination with anti-PD-L1 is associated with immune cell activation and anti-tumor response. In order to validate the dual mechanism of action in vivo, studies in mice and cynomolgus monkeys were conducted. Firstly, KY1044 injected i.v. at doses up to 100 mg/kg weekly were well tolerated in non-human primates. In addition, pharmacodynamic studies in mice and cynomolgus monkey confirm preferential depletion of ICOSHigh cells. KY1044-CT01 is an open-labelled first in human Phase I/II study assessing the safety, tolerability, PK, PD and anti-tumor activity of KY1044 administered every 3 weeks (Q3W) as an i.v. single agent infusion and in combination with atezolizumab (1200 mg, Q3W IV) in adult patients with advanced/metastatic malignancies. The primary endpoint of the Phase I dose escalations, designed as sequential but overlapping arms of KY1044 monotherapy and combination with atezolizumab, is safety and tolerability. Secondary endpoints are the characterization of pharmacokinetic, pharmacodynamic and efficacy profiles in all patients. In the Phase II part, the primary endpoint is overall response rate (ORR), and the measure of clinical efficacy will be confirmed as per RECIST 1.1. and immune-related (ir)RECIST. An intensive biomarker plan is integral to the study design to underpin the phenotypic and molecular changes in both peripheral blood and tumor. Clinical trial information: NCT03829501.

Abstract PD4-04: Combined inhibition of mTOR and CDK4/6 is required for optimal blockade of E2F function and long term growth inhibition in estrogen receptor positive breast cancer

The cyclin dependent kinase (CDK) –retinoblastoma (RB) -E2F pathway plays a critical role in the control of cell cycle in estrogen receptor positive (ER+) breast cancer. Small molecule inhibitors of CDK4/6 have shown promise in this tumour type in combination with hormonal therapies, reflecting the particular dependence of this subtype of cancer on cyclin D1 and E2F transcription factors. mTOR inhibitors have also shown potential in clinical trials in this disease setting. Recent data has suggested cooperation between the phosphatidylinositol 3-kinase (PI3K) pathway and CDK4/6 inhibition in preventing early adaptation and eliciting growth arrest, but the mechanisms of the interplay between these pathways have not been fully elucidated. Here we show that profound and durable inhibition of ER+ breast cancer growth is likely to require multiple hits on E2F mediated transcription. We demonstrate that inhibition of mTOR using the mTORC1/2 inhibitor vistusertib at 300nM causes a >50% decrease in cyclin D1 protein levels and RB phosphorylation in three cell lines. At these concentrations, vistusertib treatment also elicits marked effects on E2F mediated transcription, causing changes in the mRNA levels of 28 out of 43 (65%) of a selected set of E2F target genes.Combined inhibition of mTOR, CDK4/6 and ER delivers profound and durable regressions in breast cancer cell lines and xenografts (110.2% tumour growth inhibition at day 48). In vivo data show, that over a period of 58 days, tumours failed to re-grow in the presence of the triplet combination compared to either agent alone, suggesting, that the triplet is necessary to maintain growth inhibition. Furthermore, we show that CDK4/6 inhibitor resistant cell lines re-activate the CDK-RB-E2F pathway, but remain sensitive to mTOR inhibition (EC50 52.7 nM in parental cells vs 39.6-73.3 nM in a number of palbociclib resistant cell populations), suggesting that mTORC1/2 inhibitors may represent an option for patients that have relapsed on CDK4/6 therapy. A Phase I study (PASTOR) combining the dual TOR kinase inhibitor Vistusertib with Palbociclib, and Fulvestrant is underway to explore safety and efficacy of the triplet combination in patients with metastatic breast cancer.

Citation Format: Oelmann E, Michaloglou C, Crafter C, Siersbaek R, Delpuech O, Curven J, Carnevalli L, Staniszweska A, Polanska U, Cheraghchi-Bashi A, Lawson M, Chernukhin I, McEwen R, Carroll J, Cosulich S. Combined inhibition of mTOR and CDK4/6 is required for optimal blockade of E2F function and long term growth inhibition in estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-04.

Expression of Interleukin-1 and Interleukin-1 Receptors Type 1 and Type 2 in Hodgkin Lymphoma

Signaling through the IL-1-receptor type 1 (IL-1R1), IL-1 is required for initiation and maintenance of diverse activities of the immune system. A second receptor, IL-1R2, blocks IL-1 signal transduction. We studied expression of IL-1beta, IL-1R1, and IL-1R2 in 17 Hodgkin lymphomas (HL) by in situ hybridization (ISH). IL-1beta expressing cells, morphologically consistent with endothelial cells and fibroblasts, occurred in all HL tissues with elevated transcript levels in areas of active fibrosis. Hodgkin and Reed-Sternberg (HRS) cells of all cases expressed low IL-1R1 transcript levels in some tumor cells, and high levels of IL-1R2 in large proportions of HRS cells. Only few bystander cells showed low levels of IL-1R1 and IL-1R2 RNA. Supernatants of 4 out of 7 HL-derived cell lines contained soluble IL-1R2 protein at high levels. HL patient sera carried variably amounts of IL-1R2 protein with significantly increased titers in patients with active disease compared to patients in complete remission and control individuals without HL. Western blots and co-immunoprecipitations showed binding of the IL-1R2 to the intracellular IL-1R-accessory protein (IL-1IRAcP). These data suggest functions of the IL-1R2 as a „decoy-receptor” sequestrating paracrine IL-1 extracellularly and intracellularly by engaging IL-1IRAcP, thus depriving IL1-R1 molecules of their extracellular and intracellular ligands. Expression of IL1-R2 by HRS cells seems to contribute to local and systemic modulation of immune function in HL.

Abstract CT233: A phase I study evaluating continuous and intermittent AZD2014 in combination with fulvestrant in patients with ER+ advanced metastatic breast cancer

Background: Preclinical and clinical (BOLERO 2) data suggest that pts with ER+ breast cancer become less sensitive to hormonal therapy over time with greater dependency on the mTOR pathway. AZD2014 is a selective dual mTORC1 and mTORC2 inhibitor that may offer additional benefit vs mTORC1 inhibitors through suppression of AKT via mTORC2. Preclinical data demonstrate that continuous or intermittent dosing schedules are equally effective in a model of ER+ breast cancer and the latter may achieve improved tolerability in pts. This Ph I trial assesses the safety, tolerability, PK, PD and preliminary efficacy of AZD2014 administered both continuously and intermittently in combination with fulvestrant (F); data are unvalidated and subject to change.

Methods: Adult pts with ER+ metastatic breast cancer were treated with continuous or intermittent AZD2014 in combination with F 500mg intramuscularly on day 1 of each 28 day cycle.

Results: In the continuous schedules, 43 pts have been treated in 4 cohorts: 50mg BD = 13; 35mg BD = 6; 100mg QD = 10; and 75mg QD = 14. In the intermittent schedules 23 pts have been treated on D1 and 2 (2 days out of 7) per week in 2 cohorts: 170mg BD = 8; 125mg BD = 15. DLTs on the continuous schedule included rash/stomatitis (1 pt) and hyperglycemia (1 pt) at 50mg BD; fatigue (1 pt) and stomatitis (1 pt) at 100mg QD; and rash (1 pt) at 75mg QD. There were no DLTs at 170mg or 125mg BD (D1&2) on the intermittent schedule. Treatment-related toxicities (any grade) in 66 pts include: nausea (58%), fatigue (52%), diarrhea (46%), stomatitis (41%), vomiting (32%), decreased appetite (30%), maculo-papular rash (26%), and hyperglycemia (15%). PK data show that AZD2014 is rapidly absorbed (median tmax 1-1.75h). The mean single dose terminal elimination t1/2 was 3.3-5.6h and increased following multiple and/or high dosing. There was no evidence that co-administration of F had a clinically relevant impact on AZD2014 exposure. Inhibition of both mTORC1 and 2 was observed in both surrogate and tumor tissue. In the 49 pts with measureable disease, 9 confirmed (duration 1.8-22 months) and 3 unconfirmed PRs were observed. Overall, CBR (CR+PR+SD >24 weeks) was 29/66.

Conclusion: Continuous and intermittent dosing of AZD2014 in combination with F is tolerable with clinical benefit observed in 44% of all pts with clinical activity observed with both schedules. Toxicities observed with the continuous dosing schedule are broadly consistent with AEs observed in other trials with mTOR inhibitors. Notably, the intermittent schedule had a different AE profile with a lower incidence of rash. AZD2014 inhibited both mTORC1 and mTORC2 in surrogate and tumor tissue and the PK data were broadly consistent with previous findings for AZD2014 single agent. A randomized phase II trial of the combination comparing both the continuous and intermittent dosing schedules is ongoing.

Citation Format: Manish Patel, Erika Hamilton, Patricia M. LoRusso, W. Larry Gluck, Suzanne F. Jones, Muaiad Kittaneh, Sabina Cosulich, Elizabeth A. Harrington, Stephen Green, Wendy Burke, Donald K. Strickland, Elisabeth Oelmann, Howard A. Burris. A phase I study evaluating continuous and intermittent AZD2014 in combination with fulvestrant in patients with ER+ advanced metastatic breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT233. doi:10.1158/1538-7445.AM2015-CT233

Abstract P6-12-01: A phase I study evaluating AZD2014 in combination with fulvestrant in patients with ER+ advanced metastatic breast cancer

Background: Preclinical data suggest that patients with ER+ Breast Cancer become less sensitive to hormonal therapy by upregulation of the mTOR pathway. BOLERO-2 demonstrated that the combination of an allosteric mTOR inhibitor and an aromatase inhibitor improves progression-free survival in postmenopausal women with hormone resistant advanced breast cancer (NEJM 2012; 366:520-529). AZD2014 is a selective dual mTORC1 and mTORC2 inhibitor whilst fulvestrant is an estrogen receptor antagonist that is approved for the treatment of postmenopausal women with disease progression following antiestrogen therapy. This phase I trial assessed the safety, tolerability, pharmacokinetics, and preliminary efficacy of AZD2014 administered in combination with fulvestrant.

Methods: Continuous BID or QD dosing of AZD2014 was administered in combination with fulvestrant 500 mg intramuscularly on day 1 of each 28 day cycle. An additional 500 mg dose of fulvestrant was administered on day 15 of cycle 1 as per the approved dosing schedule. Single and multiple dose AZD2014 and fulvestrant pharmacokinetic samples were obtained. Optional tumor biopsies were also obtained.

Results: 43 patients (median age 61, range 32-82 years; prior chemo in the metastatic setting = 25; prior hormonal therapy = 43) have been treated in 4 dosing cohorts: 50 mg BID = 13; 35 mg BID = 6; 100 mg QD = 10; and 75 mg QD = 14. Patients have received 302+ treatment cycles (median 5 cycles/patient, range 1-21) and 4 patients continue on treatment. Review of preliminary unvalidated safety and Pk data revealed that dose-limiting toxicities included rash/mucositis (1 pt) and hyperglycemia (1 pt) at 50 mg BID; fatigue (1 pt) and mucositis (1 pt) at 100 mg QD; and rash (1 pt) at 75 mg QD. Treatment-related toxicities (any grade) include: fatigue (51%), mucositis (60%), rash (60%), nausea (47%), hyperglycemia (12%), and neutropenia (2%). Pharmacokinetic data show that AZD2014 is rapidly absorbed with a median time to maximum concentration of 1-1.75 hours and an estimated mean half-life of approximately 3.3-5.6 hours across the dose range. There is no evidence that co-administration of fulvestrant has a clinically relevant impact on exposure to AZD2014. In the 26 patients with measureable disease, 5 confirmed PRs have been observed (duration 4-18+ months) with an additional 14 patients experiencing stable disease for at least 6 months of treatment.

Conclusion: Continuous QD (75mg) and BID (35 and 50 mg) administration of AZD2014 in combination with fulvestrant is tolerable with clinical benefit observed in nearly half of the patients. Toxicities observed are broadly consistent with AEs observed in other trials with antihormonal agents and other mTOR inhibitors, but seem to be well manageable. There were no new or other additive toxicities, when the two drugs were combined and AZD2014 pharmacokinetic data are broadly consistent with what has been previously observed for AZD2014 single agent. A randomized phase II trial of the combination is ongoing and an intermittent weekly dosing schedule is being explored in additional patient cohorts in the current study.

Citation Format: Howard Burris III, Patricia LoRusso, W Larry Gluck, Suzanne Jones, Muaiad Kittaneh, Erika Hamilton, Stephen Green, Wendy Burke, Donald Strickland, Elisabeth Oelmann, Manish Patel. A phase I study evaluating AZD2014 in combination with fulvestrant in patients with ER+ advanced metastatic breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-12-01.

First-in-Human Pharmacokinetic and Pharmacodynamic Study of the Dual m-TORC 1/2 Inhibitor AZD2014

PURPOSE

AZD2014 is a novel, oral, m-TORC 1/2 inhibitor that has shown in vitro and in vivo efficacy across a range of preclinical human cancer models.

EXPERIMENTAL DESIGN

A rolling six-dose escalation was performed to define an MTD (part A), and at MTD a further cohort of patients was treated to further characterize toxicities and perform pre- and posttreatment biopsies (part B). AZD2014 was administered orally twice a day continuously. Flow cytometry, ELISA, and immunohistochemistry were used to quantify pharmacodynamic biomarkers. Pharmacokinetic analysis was carried out by mass spectrometry.

RESULTS

A total of 56 patients were treated across a dose range of 25 to 100 mg. The MTD was 50 mg twice daily. The dose-limiting toxicities were fatigue and mucositis. At the MTD, the most common adverse events (AE) were fatigue (78%), nausea (51%), and mucositis (49%), but these were equal to or greater than grade 3 in only 5% of patients. Drug levels achieved at the MTD (AUC SS: 6686 ng·h/mL, Cmax ss 1,664 ng/mL) were consistent with activity in preclinical models. A reduction in p-S6 levels and Ki67 staining was observed in 8 of 8 and 5 of 9 evaluable paired biopsy samples. Partial responses were seen in a patient with pancreatic cancer and a patient with breast cancer, who were found to have a PDGFR and ERBB2 mutation, respectively.

CONCLUSIONS

The recommended phase II dose for further evaluation of AZD2014 is 50 mg twice daily, and at this dose it has been possible to demonstrate pharmacologically relevant plasma concentrations, target inhibition in tumor, and clinical responses.

Safety, tolerability, pharmacokinetics and pharmacodynamics of AZD8055 in advanced solid tumours and lymphoma

Background:

This study assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of the first-in-class dual mammalian target of rapamycin complex (mTORC)1/mTORC2 inhibitor, AZD8055.

Methods:

Patients with advanced solid malignancies or lymphomas were recruited into this phase I, open-label, dose-escalation study of AZD8055 starting at 10 mg twice-daily oral dosing (BID).

Results:

Forty-nine patients received AZD8055. Dose-limiting toxicities were reported at 40 mg (n=1), 90 mg (n=1) and 120 mg (n=3) BID; all were grade 3 rises in transaminases, reversible in all patients, apart from one who had liver metastases. The maximum tolerated dose was defined as 90 mg BID. The most frequent adverse events assessed to be related to AZD8055 were increased alanine aminotransferase (22%), increased aspartate aminotransferase (22%) and fatigue (16%). AZD8055 was rapidly absorbed (median t_max ∼0.5 h) and exposure increased with increasing doses. Seven patients had stable disease for ⩾4 months. Partial metabolic responses, assessed by fluorodeoxyglucose positron emission tomography, were observed at ⩾40 mg BID (n=8 at day 35).

Conclusion:

The maximum tolerated dose for AZD8055 is 90 mg BID. Apart from elevated transaminases, which occurred at most dose levels, the drug had an acceptable toxicity profile; however, no RECIST responses were seen.

First-in-human phase I trial of the dual mTORC1 and mTORC2 inhibitor AZD2014 in solid tumors

3004

Background: AZD2014 is a potent, dual mTORC1/mTORC2 inhibitor with clear activity in in vivo and in vitro experimental models. Methods: This 2-part study consisted of "rolling six" dose escalation (Part A) and expansion (Part B) phases. Part A: 3–6 pts per cohort received an oral solution of AZD2014 BD starting at 50 mg. A further 6 pts were treated in Part A below the MTD to study changes in pharmacodynamic (PD) biomarkers. Part B: additional pts were dosed at the MTD, including a group of ER+/PR+ or HER2+ patients with breast cancer. Primary endpoint: safety and tolerability; secondary endpoints: pharmacokinetics (PK), PD and efficacy. Biomarkers assessed: mTORC1: pS6 (S235/236) and p4EBP1 (T37/46); mTORC2: pAKT (S473). Results: 50 pts have been enroled in this ongoing study and interim data are reported: Part A, n=23 (25 mg, n=6; 50 mg, n=8; 70 mg, n=5; 100 mg, n=4; all BD); Part B, n=27. The MTD was 50 mg BD. DLTs were seen at both 100 mg (Gr 2 and 3 lethargy/fatigue, n=4/4) and 70 mg (Gr 3 mucositis, Gr 2 lethargy, n=2/4); no DLTs were seen at 25 mg or 50 mg. The most common AEs in order of incidence were fatigue, stomatitis, decreased appetite, nausea and diarrhea. Seven SAEs (nausea, vomiting, lethargy, abdominal pain, mucositis) reported by 3 pts were considered ‘possibly related’ to the study drug by investigators. AZD2014 is rapidly absorbed following single and BD multiple doses with a short t1/2 of ~3 h. At 50 mg (n=32), preliminary data show geometric mean AUCss=7.4 µg.h/ml and Cmax ss=1.7 µg/ml. One pt with acinar pancreatic cancer had a RECIST partial response. pAKT and p4EBP1 reductions were observed between 2–8 h in platelet-rich plasma and peripheral blood mononuclear cells respectively. Target modulation in paired tumor biopsies was seen at the MTD. Reduction in the phosphorylation of S6 and 4EBP1 was evident in 8/10 and 3/9 paired biopsies respectively. pAKT was reduced in 3/6 evaluable paired biopsies. As opposed to rapalogs, pAKT was not upregulated in any of the evaluable post-treatment biopsies. Conclusions: The MTD for AZD2014 is 50 mg BD. Further clinical evaluation of AZD2014 is now warranted based on the safety, PK and proof-of-mechanism PD data, as well as its preliminary clinical activity. Updated results will be presented.

Growth inhibition and induction of apoptosis in acute myeloid leukemia cells by new indolinone derivatives targeting fibroblast growth factor, platelet-derived growth factor, and vascular endothelial growth factor receptors

In acute myeloid leukemia (AML), receptor tyrosine kinase ligands promote growth and survival and contribute to AML-associated marrow neoangiogenesis. We have tested simultaneous inhibition of vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor receptor signaling by novel indolinone derivatives using 14 myeloid, including 11 human leukemic, cell lines. Compounds inhibited colony formation of all cell lines in a dose-dependent fashion. Inhibitory concentrations for 50% of the colony formation/survival (IC50) for BIBF1000 were <100 nmol/L for 3 of 11, <or=500 nmol/L for 6 of 11, and <1,000 nmol/L for 10 of 11 leukemic cell lines, with one cell line being resistant in the dose range <1,000 nmol/L. BIBF1120 was less effective with 4 of 11 leukemic cell lines being resistant within the dose range <1,000 nmol/L. Testing of myeloid 32D cells transfected with empty vector, wild-type Flt3, or Flt3 carrying an internal tandem duplication mutation revealed higher resistance for the internal tandem duplication mutant. These effects of the compounds were associated with inhibition of tyrosine phosphorylation and the mitogen-activated protein kinase pathway. Furthermore, both compounds induced apoptosis in the sensitive cell lines. In Mono-Mac1 cells, the compounds had a direct proapoptotic effect that was increasing the proapoptotic effect of 1-beta-D-arabinofuranosylcytosine. The data provide a rationale for clinical evaluation of these tyrosine kinase inhibitors in AML.

Receptor for platelet-activating factor (PAF) is not detectable by flow cytometry on the surface of myeloid leukemic cells

Flow cytometry was applied to test for platelet-activating-factor receptor (PAF-R) presence on the membranes of acute myeloid leukemia (AML) cells. We have used six human AML cell lines and freshly taken density gradient separated blasts from the bone marrow of ten AML patients covering the majority of French-American-British (FAB) subtypes. Additionally, we have used one histiocytic lymphoma cell line and mature human granulocytes/monocytes as controls. Our results indicate lack of membrane PAF-R on AML of all FAB subtypes tested. This was particularly true for the more mature and differentiated subtypes M4 and M5, including monocytic cell elements, and the promyelocytic M3 AML. In contrast, membrane PAF-R could be easily detected in a histiocytic lymphoma cell line and mature granulocytes/monocytes from peripheral blood used as positive controls. In conclusion, this observation precludes the use of membrane PAF-R as an immunophenotypic marker for AML classification or detection of minimal residual disease.

Influence of keratinocyte growth factor on clonal growth of epithelial tumor cells, lymphoma and leukemia cells and on sensitivity of tumor cells towards 5-fluorouracil in vitro

RhKGF is developed for prevention and treatment of chemotherapy- and radiation-induced epithelial damage in cancer patients. Little information exists on growth modulation of malignant cells by KGF. We have tested the anchorage-independent clonal growth of 35 human tumor and 22 lymphoma and leukemia cell lines in semisolid media with or without rhKGF. Growth of the majority of cell lines was not significantly influenced by rhKGF. Growth of 5 cell lines (2 lung, 1 stomach, 1 colorectal, 1 breast) was significantly stimulated by rhKGF. The effect was dose-dependent with significant stimulation at concentrations >1-10 ng/ml. Growth modulation was amplified by serum reduction and abolished by anti-hKGF antibodies. Responding cell lines expressed KGF receptor RNA and showed specific KGF-binding. To determine whether KGF-induced higher colony numbers represented cell divisions with resulting differentiation and growth arrest or self-renewal we performed experiments on serial plating efficacy of colony-derived tumor cells with or without continued presence of rhKGF. Results revealed KGF stimulation of colony formation as representing increase of cellular self-renewal. To test possible interaction of rhKGF with activity of cytotoxic drugs in clinical protocols, we have used combination protocols with 5-fluorouracil (5-FU). Results showed that rhKGF incubation before, after (or both) addition of 5-FU did not diminish the sensitivity of tumor cells to 5-FU cytotoxicity under serum concentrations relevant for the clinical situation. In conclusion, some epithelial tumor cells have receptors for KGF signaling for clonal growth. When considered in the planning of treatment protocols, this effect is unlikely to compromise chemotherapy sensitivity.

Graft-versus-host disease after allogeneic hematopoietic stem cell transplantation induces a CD8+ T cell-mediated graft-versus-tumor effect that is independent of the recognition of alloantigenic tumor targets

Cure of hematologic malignancies after allogeneic hematopoietic stem cell transplantation is partially attributable to immunocellular antitumor reactions termed graft-versus-tumor (GvT) effect. GvT effects are heterogeneous with respect to effector cell populations, target antigens, and their interrelation with graft-versus-host disease (GvHD). In the present study, allogeneic parent-into-F1 murine transplantation models (BALB/c or C57BL/6 --> [C57BL/6 x BALB/c]F1) with different tumors derived from either parental strain were used to evaluate tumor-specific GvT effects. Compared with syngeneic F1-into-F1 controls, significant CD8+ T cell-mediated GvT effects occurred in both allogeneic transplantation models, even in the absence of histoincompatibilities between donor cells and host tumor. Identical genetic background of donor and tumor precluded allorecognition of tumor cells, indicating that tumor-associated antigens (TAAs) were targeted. With allowance made for selective major histocompatibility complex (MHC) disparities between donor cells and normal host tissue, GvHD was identified as a driving force for TAA-specific GvT effects. Adoptive transfer of the effector cells into secondary tumor-bearing recipients confirmed sustained antitumor activity and specificity of the T-cell response. The results provide experimental proof of a donor CD8+ T cell-mediated TAA-specific antitumor response in vivo that is driven by GvHD. It may represent one of the mechanisms contributing to GvT effects observed in allogeneic transplant recipients.

Early tandem high-dose ifosfamide, carboplatin, etoposide therapy with stem cell rescue for small-cell lung cancer: brief report on the results of a phase-I/II trial

OBJECTIVE

High-dose therapy (HDT) for small-cell lung cancer is experimental. Late intensification HDT for chemosensitive disease can increase the number and quality of remissions and prolong relapse-free survival, but has not yet shown impact on overall survival. This is possibly due to resistant residual disease. To overcome the development of resistance, we have tested early intensification tandem HDT.

METHODS

We performed a phase-I/II trial using 1 conventional cycle of ifosfamide, carboplatin, etoposide (ICE) plus granulocyte colony-stimulating factor for stem cell recruitment followed by 2 cycles of high-dose ICE with rescue by CD34+ cell-enriched peripheral blood mononuclear cells. Dose escalation was performed for the 2 high-dose ICE cycles. Radiotherapy for limited disease was according to standard protocols.

RESULTS

17 patients were entered: 2 female patients; 15 male patients; median age 53 (range 36-65) years; 2 patients with limited disease, and 15 patients with extensive disease. We treated 4 patients at dose level 1, 11 patients at level 2, and 2 patients at level 3. The maximum tolerable dose was at level 2 with neuropathy being dose-limiting. Overall, toxicity was < or = grade 2 for all patients up to dose level 2 with hematotoxicity being grade 4 for all patients. There were 15 partial remissions (88%), 1 no change (6%), and 1 progressive disease (6%). Median time to progression was 7.9 months. Overall survival was 12.9 months (median).

CONCLUSIONS

Early intensification with this protocol is feasible. Although a comparatively good response rate and median time to progression have been observed in this group dominated by patients with extensive disease, overall survival is short and no substantial long-term survival was found.

Interleukin 8 and Flt3 ligand as markers of advanced disease in primary gastrointestinal non-Hodgkin's lymphoma

Tumor angiogenesis plays a significant role in cancer growth and metastasis. This complex process is influenced by a variety of angiogenic factors. Elevated serum levels or high expression of some of these factors have been shown to correlate with stage and prognosis in certain human malignancies. This has been demonstrated most consistently for vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). We tried to establish, whether pre-treatment serum levels of the angiogenic factors VEGF, bFGF, interleukin 8 (IL-8) and Flt3 ligand (Flt3L) correlate with prognostic variables in 30 patients with primary gastro-intestinal non-Hodgkin's lymphoma. Our results suggest that higher pretreatment serum levels of IL-8 and Flt3L are associated with higher stage (>or= II) and high grade, respectively. Elevated pretreatment serum levels of VEGF and bFGF were not associated with advanced disease characteristics and carried no prognostic information.

Tissue inhibitor of metalloproteinases 1 is an autocrine and paracrine survival factor, with additional immune-regulatory functions, expressed by Hodgkin/Reed-Sternberg cells

Tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 are proteins with proteinase-inhibiting and cytokine properties. TIMP-1 is active primarily in B cells and B-cell lymphomas, whereas TIMP-2 expression is restricted to T cells. The expression of TIMP-1 and TIMP-2 in lymph nodes from patients with Hodgkin disease (HD) and in Hodgkin-derived cell lines was investigated. In situ hybridization showed TIMP-1 RNA expression in 3% to 80% of Hodgkin/Reed-Sternberg (H/R-S) cells from 14 of 15 patients, with results in one patient being at the lowest detection limit; no expression of TIMP-2 in H/R-S cells; and only weak expression of TIMP-2 in reactive lymphoid tissue. Production of TIMP-1 protein by H/R-S cells was accordingly found on immunohistochemical analysis of lymph nodes from patients with HD. There was only low expression of matrix metalloproteinase (MMP)-2, which is mainly inhibited by TIMP-2; no expression of MMP-1 and MMP-3 in reactive lymphoid tissue; and no expression of these MMPs in H/R-S cells. Thus, TIMP-1 expression in lymph nodes was not correlated with metalloproteinase expression. Five of 7 Hodgkin-derived cell lines expressed TIMP-1 at the protein level. Only one of these cell lines expressed TIMP-2, at the lowest detection limit. TIMP-1 levels in plasma from patients with HD were within the same range as those in plasma from healthy controls. Recombinant human TIMP-1 inhibited induced cell death in Hodgkin-derived cell lines in vitro. TIMP-1 and TIMP-2 inhibited T-cell cytotoxicity against autologous cells presenting tumor-associated antigens and in allogeneic mixed lymphocyte cultures. Thus, TIMP-1, aside from its role in proteinase equilibrium, is an autocrine and paracrine survival factor for H/R-S cells and an immunosuppressive protein expressed in Hodgkin lymphomas.

Simultaneous immunomagnetic CD34+ cell selection and B-cell depletion in peripheral blood progenitor cell samples of patients suffering from B-cell non-Hodgkin's lymphoma

The reduction of residual tumor cells is one of the main targets of leukapheresis product (LP) processing. Immunomagnetic enrichment/selection of CD34+ progenitor cells (Baxter Isolex 300i) can achieve a reduction of contaminating B-cells of approximately 2-3 logs in B-cell non-Hodgkin's lymphoma patients. Specific release of the enriched CD34+ cells (stem cell releasing agent PR34+; Baxter) and the use of antibody-coated immunobeads targeted against B-cell markers (CD10, CD19, CD20, CD22, CD23, and CD37) during this procedure allows the GMP-like simultaneous capture of residual B cells within a closed system. This combination of two purging techniques enhances the B-cell depletion capacity up to 4.5 logs. By performing 10 clinical-scale purging procedures, we could show that the simultaneous immunomagnetic purging method is easy to perform and highly efficient. We evaluated B-cell log depletion by flow cytometry for cases with marker-positive cells detectable before and after the purging procedure. The mean reduction of B-cells in these cases was 3.5 logs; the mean CD34+ cell yield and purity were 47 and 92%. Using three LPs, we tested the procedure on a modified Baxter Isolex 300i device with software adaptations for this procedure (software version 2.0) in direct comparison with CD34+ cell selection only, using the former version (version 1.12). The CD34+ cell yield was 49% (40-54%) for the CD34+ cell selection and 51% (19-72%) for simultaneous double selection. The mean purity was 96% for CD34+ cell selection and 98% for simultaneous double selection. B-cell depletion was 1.9 logs for CD34+ cell selection, and after simultaneous double selection, the B-cell content was decreased by 3.7 log steps (P = 0.0495). Clinical application of double-purged cells has not prolonged the hematopoietic recovery times after high-dose therapy as compared with nonpurged peripheral blood progenitor cell autotransplants. In conclusion, we could show that the simultaneous double selection protocol developed leads to a highly increased B-cell purging efficacy when compared with CD34+ cell selection without any negative effects regarding CD34+ cell yield and engraftment times after high-dose therapy.

Constitutive activation of FLT3 in acute myeloid leukaemia and its consequences for growth of 32D cells

The receptor tyrosine kinase Flt3 is expressed on leukaemic blasts of most cases with acute myeloid leukaemia (AML). In order to evaluate the presence and significance of constitutive activation of Flt3 for leukaemogenesis, we (1) analysed the expression and activation status of the receptor in AML blasts; and (2) evaluated the functional consequences of constitutively active Flt3 in a myeloid progenitor cell line. Immunoprecipitation studies revealed Flt3 expression in a high proportion of AML cases (27/32) with ligand-dependent Flt3 autophosphorylation in 18, constitutive autophosphorylation in three and no autophosphorylation in six cases. Only one out of three samples with constitutively active Flt3 but 3/18 samples with ligand-dependent autophosphorylated Flt3 contained the recently described internal tandem repeat (ITR) mutations. To test the significance of Flt3 activation in myeloid cell function, we also characterized the biochemical and biological effects of the activating mutation D838V of Flt3 (FLt3D838V) on the factor-dependent myeloid progenitor cell line 32Dcl3: cells transfected with wild-type Flt3 (32D/Flt3) grew FLt3 ligand (FL) dependent, and the receptor was ligand dependently autophosphorylated. In contrast, the receptor was constitutively autophosphorylated in 32D/Flt3D838V cells, which grew independently of FL. We conclude that, in some AML samples, Flt3 is constitutively activated and that this does not correlate with ITR mutations in the juxtamembrane domain. Furthermore, constitutively active Flt3 confers factor independence to the myeloid progenitor cell line 32D. It remains to be determined whether activation of Flt3 is leukaemogenic in vivo and whether strategies aimed at inhibition of Flt3 activation could inhibit leukaemogenesis.

Autocrine interleukin-1 receptor antagonist can support malignant growth of glioblastoma by blocking growth-inhibiting autocrine loop of interleukin-1

In situ hybridization (ISH) of human glioblastoma tissue sections revealed expression of interleukin-1 (IL-1)alpha and/or beta and IL-1 receptor types I and II (IL-1R I and II) in the majority of cases evaluable. To understand the function of IL-1-family members in human glioblastomas, we have studied 6 glioblastoma cell lines. RT-PCR, ISH, ELISA and 125I-IL-1-binding assays revealed expression of IL-1 and high-affinity receptors for human (h)IL-1 in all but 1 cell line. Using a colony growth assay in semi-solid media for testing serial plating efficacy (PE, number of colonies per number of cells seeded in %), only the IL-1R-negative cell line was not influenced by recombinant human (rh)IL-1alpha or -beta, whereas IL-1 down-regulated the self-renewal of clonogenic cells of the other glioblastomas. Tritiated thymidine uptake was down-regulated by rhIL-1 in all cell lines studied. Cell viability remained unchanged by rhIL-1. Wherever growth modulation by rhIL-1 was detected, it could be reversed by either soluble IL-1R I or II or by rhIL-1 receptor antagonist (ra). IL-1ra not only was able to reverse rhIL-1-induced growth modulation but alone could modulate glioblastoma growth in comparison with control in cell lines producing IL-1. Our results show the presence of public autocrine loops for IL-1 leading to growth inhibition in some glioblastomas. To understand these loops, we have studied expression and function of IL-1ra in glioblastomas. ISH of human glioblastoma tissue sections revealed expression of hIL-1ra in all 8 cases evaluable. In 4 of 6 cell lines, IL-1ra was found in the supernatant under constitutive conditions, the IL-1R-negative line being among the 2 non-producers. The other non-producing cell line, HTB 17, showed expression of hIL-1R II. Most interestingly, a neutralizing antibody against IL-1ra down-regulated growth of IL-1- and IL-1ra-producing glioblastoma cells to approx. 30% of the controls. Thus, public autocrine loops for IL-1 in human glioblastomas exist and result in growth inhibition. An autocrine production of IL-1-antagonizing molecules such as IL-1ra by these tumors can counteract this IL-1 function and represent a basic escape mechanism supporting malignant growth in some glioblastomas.

Fresh peripheral blood mononuclear cell preparations are a better starting material than bone marrow after cryopreservation for immunomagnetic harvesting of CD34(+) hematopoietic cells

Immunomagnetic separation using anti-CD34 monoclonal antibodies and paramagnetic microspheres has been used to enrich hematopoietic stem cells from human bone marrow, whole cord blood, or mobilized peripheral blood mononuclear cell collections. This method has been reported to achieve high separation purity of CD34+ cells in small scale experiments with fresh material. The aim of the present study was to compare the efficacy of the CD34+ cell selection technique, when thawed bone marrow or fresh peripheral blood mononuclear cells were enriched. Starting with thawed bone marrow containing 2.9% CD34+ cells the final product purity was 67.7% with a 6% CD34+ cell yield (enrichment factor 25.7), and a 85-fold CFU-GM enrichment. Using fresh mobilized peripheral blood mononuclear cells the released cells contained 77.6% CD34+ cells with a 47% yield (enrichment 86.5-fold), and a 46-fold CFU-GM enrichment. These results indicate that CD34+ cells can be selected from cryopreserved bone marrow using immunomagnetic procedures. However, fresh leukapheresis products seem to be a much better material for a positive immunomagnetic stem cell selection technique in terms of purity, yield and enrichment.

Inhibition of proliferation and clonal growth of human breast cancer cells by interleukin 13

We tested the influence of recombinant human interleukin (rhIL)-l3 and rhIL-4 on clonal growth of human breast cancer cell lines. rhIL-13 and rhIL-4 inhibited clonal growth of three of nine lines to approximately 50% of controls (ED50, 0.5 ng/ml). rhIl-13 reduced [3H]thymidine incorporation in all three cell lines: two showing a minor (84% and 83% of controls) and one showing a major response (25% of control). Both cytokines markedly reduced serum-induced G(0/1) exit (approximately 25% versus 60%). 125I-labeled interleukin (IL) 13 binding assays revealed high-affinity binding sites for IL-13 on two of the three responding cell lines (KD approximately 60 pM). (Y124D)IL-4 effectively antagonized all effects of rhIl-13 and rhIL-4, arguing for shared receptor components between them. However, neither rhIl-4 nor (Y124D) IL-4 could displace 125I-labeled IL-13 from binding, although unlabeled rhIL-13 effectively did so. Using reverse transcription-PCR, we studied the expression of the common gamma chain (gammac) in responding cell lines, putatively being shared between IL-4 receptor and IL-13 receptor; none of the three cell lines express gammac. In conclusion, we demonstrate antiproliferative effects of IL-4 and IL-13 on carcinoma cells which express IL-13 binding sites without participation of gammac.

Recombinant human stem cell factor does exert minor stimulation of growth in small cell lung cancer and melanoma cell lines

We have previously reported on the stimulation of clonal growth of a glioblastoma cell line by rhSCF (Berdel et al., Cancer Res 1992, 52, 3498-3502). Within an extensive screening programme of haematopoietic growth factor activity on malignant cells, the effects of rhSCF were further tested on the growth of 29 different human cell lines derived from a wide range of solid tumours, among them six lung cancers and five melanomas. RhSCF (0, 1, 10, 100 ng/ml) was tested in a human tumour cloning assay (HTCA) which reliably detects growth modulation of tumour cells by cytokines. Additionally, a tritiated thymidine uptake test was used. Growth of 27 of the 29 cell lines tested was not affected by rhSCF. However, growth of the small cell lung cancer (SCLC) cell line HTB 120 was slightly stimulated (1.5 fold that of controls), and that of the melanoma cell line MeWo was stimulated up to 1.3-fold. This activity was eliminated dose-dependently by the tyrosine kinase inhibitor, genistein. We further analysed the cell lines for expression of the proto-oncogene C-KIT and its ligand SCF. All melanoma and lung cancer cell lines expressed SCF as assessed at the mRNA level. Northern blotting also revealed clear C-KIT mRNA expression in three melanoma (HAS, MeWo, SK-MEL-28), one NSCLC (HTB 53), and four SCLC cell lines (HTB 119, HTB 120, HTB 171, HTB 175). Furthermore, C-KIT protein expression was detected by flow cytometric analysis on the cell surface of MeWo, HTB 119 and HTB 120 cells. Our data indicate that SCF can be operative in growth modulation of non-haematopoietic malignant cells, especially SCLC and melanoma. However, our extensive screening of SCF/tumour cell interaction shows that this interaction is rare and makes potential hazards, such as tumour stimulation upon clinical use of rhSCF in conjunction with chemotherapy in cancer patients, unlikely for the majority of other tumour histologies.

Immunomagnetic selection of CD34+ cells from fresh peripheral blood mononuclear cell preparations using two different separation techniques

Immunomagnetic separation using anti-CD34 monoclonal antibodies and paramagnetic microspheres has been used to enrich hematopoietic stem cells from human bone marrow, whole cord blood, or mobilized peripheral blood mononuclear cell collections. The aim of the present study was to compare the efficacy of two different CD34+ cell selection techniques in enriching CD34+ cells from mobilized fresh peripheral blood mononuclear cells. Using the magnetic cell sorter (MACS), the final product purity was 74.1% CD34+ cells (starting population 2.3% +/- 3.3%) with a 60.3% CD34+ cell yield. Using Dynabeads and subsequent chymopapain incubation for releasing the target cells from the beads (Isolex system), the released cells contained 83.3% CD34+ cells (starting population 1.2% +/- 0.7%) with a 43.4% yield. These results indicate that CD34+ cells can be isolated with high purity from fresh leukapheresis products using both immunomagnetic techniques.

Antiproliferative effect of human interleukin-4 in human cancer cell lines: studies on the mechanism

Interleukin-4 (IL-4) plays an important role in activating the immune system against malignant cells. The human interleukin-4 receptor (hIL-4R) is not only expressed by hematopoietic cells but also on a large number of tissue specimens which include colon, breast and lung carcinomas. In this study we report that rhIL-4 has an antiproliferative effect on 2 out of 3 non-small cell lung carcinoma (NSCLC) cell lines in vitro as measured by human tumor cloning assays (HTCA). In comparison, rhIL-4 had no effect on the growth of small cell lung carcinoma cell lines (SCLC) in vitro. The response towards the cytokine is correlated with expression of at least 1500 high affinity receptors/cell for hIL-4 on the responsive cell lines. Xenotransplanting the human lung tumor cell lines into nude mice followed by 12 days of systemic treatment of the mice with rhIL-4 revealed a significant growth retardation of the IL-4R positive NSCLC cell lines when compared with the controls, whereas the growth of the IL-4R negative SCLC cell lines was unaffected also in vivo. Studies of possible mechanisms involved in the antiproliferative effect of rhIL-4 showed that rhIL-4 does not induce apoptosis or modulation of the transcription factor c myc in the responsive NSCLC cell lines. Additionally, the expression of the epidermal growth factor receptor (EGFR), which is discussed as mediating autocrine/paracrine growth stimulation of NSCLC, is unaffected by rhIL-4. However, we have observed that rhIL-4 inhibited G1-S-phase cell cycle progression. We conclude that rhIL-4 has an antiproliferative effect on the growth of some NSCLC in vitro and in vivo. The mechanisms involved remain to be further elucidated.

Nerve growth factor stimulates clonal growth of human lung cancer cell lines and a human glioblastoma cell line expressing high-affinity nerve growth factor binding sites involving tyrosine kinase signaling

The growth of a panel of 22 different human tumor, leukemia, and lymphoma cell lines was examined in a human tumor cloning assay in agar or methylcellulose and a tritiated thymidine uptake assay. The cultures were performed in the absence or presence of increasing concentrations (0.5-500 ng/ml) of nerve growth factor (NGF). The growth of 17 of the 22 cell lines was not significantly and reproducibly affected by NGF. There was minor (1.2-fold) but reproducible stimulation of clonal growth in one glioblastoma cell line (86-HG-39) by NGF, but in this cell line NGF induced no growth modulation in a tritiated thymidine uptake assay. However, clonal growth of another glioblastoma cell line (87-HG-31) and all three lung cancer cell lines tested (HTB 119, HTB 120, CCL 185) could be stimulated up to 3-fold by NGF with a dose-response relationship for the growth factor. Growth stimulation by NGF could be completely reversed by neutralizing anti-NGF antibody and by the tyrosine kinase inhibitor genistein. Evaluation of secondary plating efficiency revealed the stimulation of colony formation as representing self-renewal and not terminal differentiation. Reverse transcriptase-PCR experiments in the five responding cell lines showed expression of both low-affinity NGF receptor (glycoprotein 75) and c-trk transcripts on the mRNA level. Of the five responding cell lines, only 86-HG-39, the cell line with the lowest responsiveness, revealed low-affinity NGF receptor on the protein level; the other four cell lines with high responsiveness, including the three lung cancer cell lines, expressed no low-affinity NGF receptor as shown by fluorescence-activated cell sorter analysis and immunoprecipitation using the ME 20.4 antibody. Immunoprecipitation using anti-trk antibodies was negative in all five responding cell lines. However, binding studies with iodinated NGF showed only low-affinity binding on the 86-HG-39 cell line and only high-affinity binding on the high-responder cell lines CCL 185 and 87-HG-31. In summary, our data suggest that NGF can be operative in stimulation of clonal growth of malignant tumor cells. High-affinity but not low-affinity binding sites mediate signal transduction for clonal growth and signaling involves tyrosine kinase activity.

Recombinant human interleukin 4 has antiproliferative activity on human tumor cell lines derived from epithelial and nonepithelial histologies

Interleukin 4, a T cell-derived 20-kDa glycoprotein, plays an important role in regulating the immune response of B cells, T cells, and macrophages against infections and malignant cells. For this reason recombinant human interleukin 4 (rhIL-4) has entered early clinical trials in cancer patients. In the present study we report that rhIL-4 has an antiproliferative effect on five of nine cell lines derived from human colon tumors, head and neck tumors, and glioblastomas as measured by a decrease of colony formation in human tumor cloning assays. All of the cell lines with in vitro responsiveness express at least 100 high-affinity receptors for human interleukin 4 per cell on their cell surface, whereas the nonresponsive tumor cell lines lack expression of high-affinity receptors for human interleukin 4 on their cell surface. In the next series of experiments we have xenotransplanted some of the responsive cell lines into athymic nude mice. Subsequently, the animals were treated s.c. twice daily with 0.5 mg/m2 rhIL-4 or control vehicle for at least 12 days. There was a clear growth inhibition of these xenotransplanted tumors in the mice treated with rhIL-4. Histology of the tumors in both groups revealed no marked infiltration with murine hematopoietic and lymphocytic cells as evaluated by staining with a rat anti-mouse CD45 antibody. We conclude that rhIL-4 has a direct therapeutic activity on the growth of some human epithelial and nonepithelial tumor cell lines which, along with its regulatory function on hematolymphopoietic cells, makes this cytokine an interesting candidate for experimental tumor therapy.

Interleukin-1 receptor antagonist inhibits growth modulation of human tumor-cell lines by interleukin-1 in-vitro

In this study we report that recombinant human (rh) interleukin-1alpha (IL-1alpha) has direct and dose-dependent growth-modulating effects on human tumor cell lines in vitro as measured by a human tumor cloning assay (HTCA). Colony formation of the melanoma cell line A 375 was inhibited by rhIL-1alpha, whereas colony formation of the glioblastoma cell line HTB 14 was enhanced by this cytokine. Both growth-modulating effects were dose-dependent, however with some saturation. Subsequently, we have tested the activity of recombinant human IL-1 receptor antagonist (rhIL-1ra) on the tumor growth modulation by rhIL-1alpha. Tumor cells were incubated with increasing concentrations of rhIL-1ra and then added to the cultures containing rHIL-1alpha. Concentrations of rhIL-1ra were chosen to achieve a range between 0.01 and 100 ng/ml which includes a 1000-fold molar excess over IL-1alpha. The receptor antagonist was able to block both the inhibition and the stimulation of clonal growth of the respective tumor cell line by rhIL-1alpha. Furthermore, there was a direct dose dependent relationship revealing higher IL-1 antagonism of rhIL-1ra at higher concentrations with maximum efficacy at 1000-molar excess concentrations over IL-1alpha. In addition, rhIL-1ra alone did not reveal major modulation of the growth of A 375, but significantly decreased colony formation of HTB 14. We conclude that rhIL-1ra can counteract modulation of clonal growth of human tumor cells by IL-1alpha in vitro. Since our report provides first evidence that the stimulation of clonal tumor cell growth by IL-1alpha can be blocked by rhIL-1ra, this member of the IL-1 cytokine network should be further studied as a possible candidate for experimental cancer treatment.

Lymphotoxin, tumour necrosis factor and interleukin-6 gene transcripts are present in Hodgkin and Reed-Sternberg cells of most Hodgkin's disease cases

Tissue specimens from 26 cases of Hodgkin's disease (HD) and six HD-derived cell lines were analysed for tumour necrosis factor (TNF), lymphotoxin (LT), and interleukin (IL)-6 RNA transcripts by in situ hybridization, in some cases subsequent to immunohistology for CD30 antigen. LT and TNF transcripts were found in tumour cells of all cases; IL-6 gene transcripts were detectable in 19/23 cases. Presence of RNA specific for these cytokines was not correlated with any of the following parameters: sex, symptoms and histotype, as well as immunophenotype and association of the tumour cells with Epstein-Barr virus. Rather, the presence of LT, TNF and IL-6 transcripts appeared to characterize Hodgkin and Reed-Sternberg cells in general, supporting concepts which suggest that HD represents a malignancy of cytokine secreting activated cells, and that many of the features distinguishing HD from other malignant lymphomas may ultimately be due to expression of cytokines. LT and TNF RNA transcripts were also found in five HD-derived cell lines, whereas supernatants of these cell lines contained high levels of LT, but low or undetectable levels of TNF activity. This suggests that, although not detectable at the level of RNA transcripts, differences between HD cases may exist on the level of cytokine gene transcript processing, translation and polypeptide secretion.