Novel arginase inhibitor, AZD0011, demonstrates immune cell stimulation and anti-tumor efficacy with diverse combination partners

Anti-tumor immunity can be hampered by immunosuppressive mechanisms in the tumor microenvironment including recruitment of arginase (ARG) expressing myeloid cells which deplete L-arginine essential for optimal T cell and natural killer cell function. Hence, ARG inhibition can reverse immunosuppression enhancing anti-tumor immunity. We describe AZD0011, a novel peptidic boronic acid prodrug to deliver an orally available, highly potent, ARG inhibitor payload (AZD0011-PL). We demonstrate that AZD0011-PL is unable to permeate cells, suggesting this compound will only inhibit extracellular ARG. In vivo, AZD0011 monotherapy leads to arginine increases, immune cell activation, and tumor growth inhibition (TGI) in various syngeneic models. Anti-tumor responses increase when AZD0011 is combined with anti-PD-L1 treatment, correlating with increases in multiple tumor immune cell populations. We demonstrate a novel triple combination of AZD0011, anti-PD-L1 and anti-NKG2A, and combination benefits with type I interferon (IFN) inducers including polyI:C and radiation. Our pre-clinical data demonstrates AZD0011's ability to reverse tumor immunosuppression and enhance immune stimulation and anti-tumor responses with diverse combination partners providing potential strategies to increase immuno-oncology therapies clinically.

PARP inhibition is a modulator of anti-tumor immune response in BRCA-deficient tumors

PARP inhibitors are synthetically lethal with BRCA1/2 mutations, and in this setting, accumulation of DNA damage leads to cell death. Because increased DNA damage and subsequent immune activation can prime an anti-tumor immune response, we studied the impact of olaparib ± immune checkpoint blockade (ICB) on anti-tumor activity and the immune microenvironment. Concurrent combination of olaparib, at clinically relevant exposures, with ICB gave durable and deeper anti-tumor activity in the Brca1m BR5 model vs. monotherapies. Olaparib and combination treatment modulated the immune microenvironment, including increases in CD8+ T cells and NK cells, and upregulation of immune pathways, including type I IFN and STING signaling. Olaparib also induced a dose-dependent upregulation of immune pathways, including JAK/STAT, STING and type I IFN, in the tumor cell compartment of a BRCA1m (HBCx-10) but not a BRCA WT (HBCx-9) breast PDX model. In vitro, olaparib induced BRCAm tumor cell–specific dendritic cell transactivation. Relevance to human disease was assessed using patient samples from the MEDIOLA (NCT02734004) trial, which showed increased type I IFN, STING, and JAK/STAT pathway expression following olaparib treatment, in line with preclinical findings. These data together provide evidence for a mechanism and schedule underpinning potential benefit of ICB combination with olaparib.

Assessment of pain associated with bovine respiratory disease and its mitigation with flunixin meglumine in cattle with induced bacterial pneumonia

Pleuritic chest pain from bacterial pneumonia is often reported in human medicine. However, studies investigating pain associated with bovine respiratory disease (BRD) are lacking. The objectives of this study were to assess if bacterial pneumonia elicits a pain response in calves with experimentally induced BRD and to determine the analgesic effects of transdermally administered flunixin. Twenty-six calves, 6-7 months of age, with no history of BRD were enrolled into 1 of 3 treatment groups: (1) experimentally induced BRD + transdermal flunixin at 3.3 mg/kg twice, 24 h apart (BRD + FTD); (2) experimentally induced BRD + placebo (BRD + PLBO); and (3) sham induction + placebo (CNTL + PLBO). Calves induced with BRD were inoculated with Mannheimia haemolytica via bronchoalveolar lavage. Outcomes were collected from -48 to 192 hours post-treatment and included serum cortisol; infrared thermography; mechanical nociceptive threshold; substance P; kinematic gait analysis; visual analog scale (VAS); clinical illness score; computerized lung score; average activity and rumination level; prostaglandin E2 metabolite; plasma serum amyloid A and rectal temperature. Outcomes were evaluated using either a generalized logistic mixed model for categorical variables or a generalized linear mixed model for continuous variables. Right front force differed by treatment (P = 0.01). The BRD + PLBO had lower mean force applied to the right front limb (85.5 kg) compared to BRD + FTD (96.5 kg) (P < 0.01). Average VAS differed by a treatment by time interaction (P = 0.01). The VAS scores differed for BRD + PLBO at -48 (3.49 mm) compared to 168 and 192 h (13.49 and 13.64 mm, respectively) (P < 0.01). Activity for BRD + PLBO was higher at -48 h (27 min/h) compared to 48, 72, 120 and 168 h (≤ 22.24 min/h) (P < 0.01). Activity differed by a treatment by time interaction (P = 0.01). Activity for BRD + FTD was higher at -48 and 0 h (28.2 and 28.2 min/h, respectively) compared to 48, 72, 96 and 168 h (≤ 23.7 min/h) (P < 0.01). Results show a combination of reduced activity levels, decreased force on the right front limb, and increased visual analog scale pain scores all support that bacterial pneumonia in cattle is painful. Differences in right front force indicate that flunixin transdermal may attenuate certain pain biomarkers in cattle with BRD. These findings suggest that BRD is painful and analgesic drugs may improve the humane aspects of care for cattle with BRD.

Abstract 1813: The genetic makeup of patient-derived xenografts shapes the immune landscape of humanized mice tumors

The complex interplay between the immune system and cancer cells is challenging to model in preclinical species. Many commonly mutated genes that influence tumorigenesis actively participate in the activation, recruitment or suppression of the immune system. A growing body of clinical findings indicates that defined oncogenic driver mutations correlate with immune contexture and associated immunotherapy responses. The goal of this study was to generate a hematopoietic stem cells (HSCs) transplanted humanized mice model using patient-derived xenografts with defined mutations to understand whether genetic alterations in the cancer cells can influence the tumor's immune landscape.

Loss of function in the tumor suppressor gene STK11/LKB1 are observed in 5-30% of NSCLC. Patients with STK11 mutations do not typically respond to immune checkpoint blockade, and analysis of patient tumor biopsies indicates that these tumors are poorly infiltrated by immune cells such as T cells and dendritic cells, but with higher density of suppressive myeloid cells and associated cytokines. Therefore, there is an interest to understand ways to improve IO responses in these patients. To determine whether we could recapitulate this biology in a preclinical model, we implanted three STK11mut and one wild type PDX on humanized mice generated from six cord blood donors, and compared the immune infiltration in these tumors.

Our results demonstrate efficient engraftment of human immune cells in the peripheral blood (53.1%), spleen (64.2%), and bone marrow (59.3%) of humanized mice (n=29, animals). Along with T and B cells, myeloid immune populations such as monocytes, macrophages and dendritic cells, which are absent in the previous generation of humanized mice, were present in the peripheral blood (monocytes 4.7%, dendritic cells 7.2% ) and bone marrow (macrophage 27.8%, neutrophils 21.6% and 10.2% dendritic cells ) of humanized mice. Tumor human immune subpopulation cells were significantly different (One-way Anova analysis) between the STK11mut (n=3) vs. wild type (n=1) humanized PDXs models (n=7 animals/PDX model). Three STK11mut tumors had low percentage of human CD45+ leukocytes infiltration (STK11mut; 0.9, 1.1 and 2.3% vs. wt; 6.6%) We also found a significantly reduced percentage of CD8+ cytotoxic T cells (STK11mut; 5.6, 3.2, 3.1% vs. wt; 9.6%) and dendritic cells subsets (STK11mut; 3.6, 2.2, 3.1% vs. wt; 5.6%) in the STK11mut PDXs implanted on humanized mice.

We have shown efficient engraftment of a multilineage human immune system in immunodeficient mice and a selective infiltration of human immune cells subsets in PDXs representing a key genetic segment of NSCLC. Our novel humanized PDX model can recapitulate human tumor immune reconstitution, providing a valuable opportunity to evaluate the benefit of immunomodulatory therapies and personalize immune intervention strategies.

Citation Format: Maneesh Singh, Laura Bradshaw, Laura B. Prickett, Griffin Matthew, Maryann San Martin, Noel Monks, Lisa Drew, Simon T. Barry, Corinne Reimer, Theresa Proia. The genetic makeup of patient-derived xenografts shapes the immune landscape of humanized mice tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1813.

Abstract 1664: Inhibition of arginase in combination with radiation therapy shows increased immune-activation and anti-tumor activity in syngeneic tumor models

The tumor microenvironment (TME) has multiple mechanisms of immune-suppression including recruitment of arginase (ARG) expressing myeloid cells. ARG is an enzyme that catalyzes hydrolysis of L-arginine into urea and L-ornithine. Given L-arginine is essential for optimal function of both T cells and natural killer (NK) cells, inhibition of ARG has been recognized as a potential therapeutic approach to reverse immune-suppression and optimize anti-tumor immunity. We recently presented development of a novel ARG inhibitor, AZD0011, and demonstrated immune activation and anti-tumor activity as single agent and in combination with a-PD-L1 in various tumor models. We now expand these findings demonstrating combination benefit with radiation therapy. Radiation therapy (5 gray on day 6 and 9 after tumor cell implant) demonstrated an increase of both the number of arginase expressing myeloid cells, and NK cells in the TME of Lewis Lung (LL) tumors. Immuno-histochemistry also demonstrated a redistribution of the location of ARG positive myeloid cells with a marked increase at the edge of the tumor. LL tumor bearing mice receiving either AZD0011 (30 mg/kg twice daily), or radiation therapy as monotherapy did not show a significant anti-tumor response reaching 0.3% and 28% tumor growth inhibition (TGI) respectively (p&gt;0.05 versus vehicle). In contrast, combination treatment showed a marked increased efficacy averaging 60% TGI (p&lt;0.05 versus either monotherapy). Combination treatment also further increased several markers of immune activation including a doubling of the number of IL2+ or IFNg+ CD4+ and CD8+ T-cells in tumor draining lymph nodes. In summary, our pre-clinical data demonstrates that radiation therapy increases the number and location of intra-tumoral ARG expression myeloid cells and increased anti-tumor activity when combining the ARG inhibitor AZD0011 with radiation therapy.

Citation Format: Alwin Schuller, Aatman Doshi, Susan Cantin, Matt Griffin, Maryann San Martin, Theresa Proia, Corinne Reimer, Scott Mlynarski, Ray Finlay, Wenlin Shao. Inhibition of arginase in combination with radiation therapy shows increased immune-activation and anti-tumor activity in syngeneic tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1664.

Discovery of AZD4573, a Potent and Selective Inhibitor of CDK9 That Enables Short Duration of Target Engagement for the Treatment of Hematological Malignancies

A CDK9 inhibitor having short target engagement would enable a reduction of Mcl-1 activity, resulting in apoptosis in cancer cells dependent on Mcl-1 for survival. We report the optimization of a series of amidopyridines (from compound 2), focusing on properties suitable for achieving short target engagement after intravenous administration. By increasing potency and human metabolic clearance, we identified compound 24, a potent and selective CDK9 inhibitor with suitable predicted human pharmacokinetic properties to deliver transient inhibition of CDK9. Furthermore, the solubility of 24 was considered adequate to allow i.v. formulation at the anticipated effective dose. Short-term treatment with compound 24 led to a rapid dose- and time-dependent decrease of pSer2-RNAP2 and Mcl-1, resulting in cell apoptosis in multiple hematological cancer cell lines. Intermittent dosing of compound 24 demonstrated efficacy in xenograft models derived from multiple hematological tumors. Compound 24 is currently in clinical trials for the treatment of hematological malignancies.

A pharmacokinetic-pharmacodynamic model for the MET tyrosine kinase inhibitor, savolitinib, to explore target inhibition requirements for anti-tumour activity

BACKGROUND AND PURPOSE

Savolitinib (AZD6094, HMPL-504, volitinib) is an oral, potent, and highly MET receptor TK inhibitor. This series of studies aimed to develop a pharmacokinetic-pharmacodynamic (PK/PD) model to link inhibition of MET phosphorylation (pMET) by savolitinib with anti-tumour activity.

EXPERIMENTAL APPROACH

Cell line-derived xenograft (CDX) experiments using human lung cancer (EBC-1) and gastric cancer (MKN-45) cells were conducted in athymic nude mice using a variety of doses and schedules of savolitinib. Tumour pMET changes and growth inhibition were calculated after 28 days. Population PK/PD techniques were used to construct a PK/PD model for savolitinib.

KEY RESULTS

Savolitinib showed dose- and dose frequency-dependent anti-tumour activity in the CDX models, with more frequent, lower dosing schedules (e.g., twice daily) being more effective than intermittent, higher dosing schedules (e.g., 4 days on/3 days off or 2 days on/5 days off). There was a clear exposure-response relationship, with maximal suppression of pMET of >90%. Data from additional CDX and patient-derived xenograft (PDX) models overlapped, allowing calculation of a single EC₅₀ of 0.38 ng·ml^-1 . Tumour growth modelling demonstrated that prolonged, high levels of pMET inhibition (>90%) were required for tumour stasis and regression in the models.

CONCLUSION AND IMPLICATIONS

High and persistent levels of MET inhibition by savolitinib were needed for optimal monotherapy anti-tumour activity in preclinical models. The modelling framework developed here can be used to translate tumour growth inhibition from the mouse to human and thus guide choice of clinical dose and schedule.

Abstract 967: Anti-tumor and immune effects of olaparib +/- anti-PD-L1 in preclinical BRCA1mut tumor models

PARP inhibitor treatments are synthetically lethal with BRCA1/2 mutations and, in this setting, accumulation of DNA damage leads ultimately to cell death. Increases in DNA damage are also associated with increased levels of cytosolic DNA and consequently signalling through the cGAS-STING pathway, which can lead to increased inflammatory gene expression and Type I interferon response.

We sought to evaluate the benefit of combining the PARP inhibitor olaparib with immune checkpoint blockade (ICB) in a mouse syngeneic ovarian model, BR5, which lacks BRCA1. We show that olaparib combination with anti-PD-L1 prolonged duration of anti-tumor response vs. either monotherapy. The combination increased durable complete responses (CRs) with 6/10 animals tumor free at 77 days, compared with 1/9 and 2/9 tumor-free animals for olaparib and anti-PD-L1 monotherapies, respectively. Similar results were observed for combination of olaparib with anti-CTLA-4. Furthermore, mice treated with olaparib + ICB demonstrated immunological memory, with 100% of mice with CRs successfully rejecting tumor growth upon rechallenge with BR5. Olaparib treatment of human T cells in vitro and mouse T cells in vitro and in vivo did not show inhibition of T cell activation or proliferation. Moreover, olaparib treatment led to changes in tumor immune infiltrate in the BR5 tumors, including approximately 2-fold increased CD8 T cells and 1.5-fold increased NK cells relative to vehicle.

Differential gene expression analysis of olaparib or anti-PD-L1treated BR5 tumors revealed broad upregulation of immune pathways. Interestingly, type I IFN and STING pathways showed a more pronounced upregulation with Olaparib than with anti-PD-L1 treatment. Moreover, a dose-dependent upregulation of immune pathways, including JAK-STAT, STING and type I IFN was observed in a tumor cell-centric analysis from a BRCA1mut breast PDX model treated with olaparib. In contrast, no significant upregulation of STING or type I IFN pathways is observed in response to olaparib in a BRCAwt breast PDX model.

In vitro mechanistic studies demonstrated that co-culture of olaparib-treated human BRCA1mut MDA-MB-436 tumor cells with human dendritic cells (DC) resulted in an approximately 2-fold upregulation of CD86 expression on DCs. Comparison of isogenic DLD-1 tumor cells showed CD86 upregulation on DCs only following co-culture with olaparib-treated BRCA2-/- DLD-1 cells, but not wt DLD-1 cells. Similarly, increased PD-L1 expression was only observed in BRCA2-/- DLD-1 cells treated with olaparib and following co-culture with DC. These observations suggest a basis for increased immune priming following olaparib treatment of BRCAmut tumors, which can be consolidated with ICB, such as anti-PD-L1, treatment.

Citation Format: Anna Staniszewska, Joshua Armenia, Matthew King, Chrysiis Michaloglou, Maneesh Singh, Maryann San Martin, Zena Wilson, Theresa Proia, Oona Delpuech, Mark O'Connor, Elisabetta Leo, Viia Valge-Archer. Anti-tumor and immune effects of olaparib +/- anti-PD-L1 in preclinical BRCA1mut tumor models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 967.

Abstract 2500: Transient CDK9 inhibition with AZD4573 modulates Bfl-1 in preclinical lymphoma models

AZD4573 is a selective cyclin-dependent kinase 9 (CDK9) inhibitor under clinical development in patients with hematological malignancies. Transient CDK9 inhibition serves as an orthogonal approach for targeting Mcl-1, a labile anti-apoptotic protein essential for the survival of cancer cells. Across-broad hematological cancer models, anti-tumor responses with AZD4573 strongly correlate with selective Mcl-1 inhibitors, such as AZD5991 (R2=0.8). Despite compelling evidence for an Mcl-1 dependent mechanism of action, we also observed a subset of lymphoma models more sensitive to CDK9 inhibition compared to Mcl-1 inhibition, suggesting acute CDK9 inhibition could be targeting other labile proteins beyond Mcl-1 to induce apoptosis. We identified Bfl-1 as one such potential target and demonstrate lymphoma models expressing Bfl-1 are highly sensitive to CDK9 inhibition.

Bfl-1 belongs to the Bcl-2 family of anti-apoptotic proteins and was detected in over 20% of lymphoma cell lines evaluated (n=33). Cycloheximide experiments indicate Bfl-1 has a short protein half-life (&lt;1h), similar to Mcl-1. Therefore, treatment with 100nM of AZD4573 in diffuse large B-cell lymphoma cell lines OCILY10 and TMD8 caused rapid down-regulation of both Mcl-1 and Bfl-1 by 4h, resulting in caspase cleavage by 6h. Evaluation of caspase activation following 6h treatment revealed an average maximum effect of 87% for AZD4573 compared to 45% with Mcl-1 inhibition, suggesting these cell lines are not exclusively Mcl-1-dependent. The hypothesis that survival of lymphoma cells may be co-dependent on both Mcl-1 and Bfl-1 was evaluated by siRNA knockdown. Following a dose-dependent suppression of Bfl-1 protein (&gt;80%) in OCILY10 and TMD8 cells, viability loss was minimal (&lt;30% reduction relative to control). However, when Bfl-1 knockdown cells were treated for 6h with an Mcl-1 inhibitor, the maximum caspase activation increased to over 90% in both cell lines, phenocopying a similar magnitude achieved with AZD4573-mediated CDK9 inhibition. In these models, depletion of both Bfl-1 and Mcl-1 was necessary to induce maximum apoptosis, with studies ongoing to evaluate single-gene Bfl-1 dependency in additional lymphoma models.

Consistent with the in vitro phenotype, intermittent dosing of the ABC-DLBCL xenografts OCILY10 and TMD8 with AZD4573 caused robust tumor regressions (198 and 184% TGI, respectively). AZD4573-mediated anti-tumor activity was associated with pharmacodynamic reductions of pSer2-RNAPII, Mcl-1 and Bfl-1, followed by caspase activation. Collectively, these findings support the ability to target Bfl-1 via CDK9 inhibition. Given the current absence of clinical small molecule Bfl-1 inhibitors and expanded monotherapy activity compared to selective Mcl-1 inhibition in a subset of preclinical models, CDK9 inhibitors have tremendous therapeutic potential in the treatment of patients with Bfl-1-expressing lymphoma.

Citation Format: Scott Boiko, Theresa Proia, Maryann San Martin, Lisa Drew, Wenlin Shao, Justin Cidado. Transient CDK9 inhibition with AZD4573 modulates Bfl-1 in preclinical lymphoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2500.

The effects of bolt length on penetration hole characteristics, brain damage and specified-risk material dispersal in finished cattle stunned with a penetrating captive bolt stunner

The purpose of this study was to determine the effect of captive bolt lengths on penetration hole characteristics, brain damage, and specified risk material (SRM) dispersal. Cattle were stunned with a pneumatic captive bolt stunner using: standard (15.2 cm; STRD), medium (16.5 cm; MED), or long (17.8 cm; LON) bolts. Heads (N = 293) and exsanguination blood (N = 103) were collected for analyses. Penetration hole diameter and depth differed by treatment (P ≤ 0.004); both parameters were greatest for LON (P < 0.05). Presence of damage in frontal, parietal, and occipital lobes, olfactory bulb, and collective area including the corpus callosum, fornix and thalamus were impacted by treatment (P < 0.003). Treatment did not impact SRM dispersal (P = 0.33), determined by presence of glial acidic fibrillary protein. Data suggest that bolt length affects both the extent of brain damage and the specific structures damaged but all bolt lengths are successful in causing substantial brain damage and subsequent insensibility.

Abstract 297: AZD4573: Mechanistic PKPD model linking CDK9 inhibition to Mcl1 depletion and induction of apoptosis in preclinical AML model

Cyclin-dependent kinase 9 (CDK9) regulates elongation of transcription through phosphorylation of RNA polymerase II (pSer2-RNAPII), and its short-term inhibition results in the selective downregulation of genes with short-lived transcripts and labile proteins - including the anti-apoptotic protein Mcl1. AZD4573 is a selective inhibitor of CDK9 with short pharmacokinetic (PK) half-life. Intermittent dosing of AZD4573 in mouse MV411 (AML cell line) xenograft models results in progressive reduction in tumor volume with the mechanism of action believed to be via induction of apoptosis following depletion of Mcl1. The aim of this work was to derive a quantitative understanding of the relationships between extent and duration of CDK9 inhibition, depletion of Mcl1 and rate of induction of apoptosis in MV411 tumor cells.

A mechanistic model has been established that quantitatively and dynamically connects AZD4573 plasma and tumor PK to the rate and extent of modulation of pSer2-RNAPII and Mcl1 in the tumor and rate of induction of cell death (as measured by reduction in tumor volume). Tumor pSer2-RNAPII and Mcl1 pharmacodynamics were modeled using a series of linked indirect response models. Production rate of pSer2-RNAPII was modeled as being directly inhibited by AZD4573 concentration in the tumor. Production rate of Mcl1 was linked to pSer2-RNAPII via a series of transit compartments to capture the transcription/translation driven delay in onset of response. Induction of intrinsic apoptosis in the MV411 tumor cells was modelled as being inhibited by Mcl1.

Tumor pSer2-RNAPII exhibited a rapid, dose-dependent decrease following IP dosing of AZD4573 in mice. The free concentration of AZD4573 that resulted in half-maximal inhibition of pSer2-RNAPII production rate was estimated to be in the range 11-21 nM. Following a brief delay, tumor Mcl1 also exhibited a relatively rapid decrease that was proportional to the pSer2-RNAPII response. Mcl1 protein half-life was estimated to be 0.3 hr. Rate of induction of apoptosis could be decribed as a saturable first-order process (Kmax ~ 0.2 hr-1) and appeared to exhibit a steep response to the depletion of Mcl1, with reduction of Mcl1 to 25% (of the baseline value) being estimated to result in half-maximal rate of induction of apoptosis in the MV411 cells.

The described MV411 PKPD/efficacy model has been assumed to be representative of AML in human patients and was used to derive preliminary predictions of clinical efficacy at a range of possible IV dosing regimens.

Citation Format: Douglas Ferguson, Theresa Proia, Justin Cidado, Scott Boiko, Maryann San Martin, Steven Criscione, Wenlin Shao, Lisa Drew. AZD4573: Mechanistic PKPD model linking CDK9 inhibition to Mcl1 depletion and induction of apoptosis in preclinical AML model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 297.

Ceftaroline efficacy against high-MIC clinical Staphylococcus aureus isolates in an in vitro hollow-fibre infection model

Objectives

The current CLSI and EUCAST clinical susceptible breakpoint for 600 mg q12h dosing of ceftaroline (active metabolite of ceftaroline fosamil) for Staphylococcus aureus is ≤1 mg/L. Efficacy data for S. aureus infections with ceftaroline MIC ≥2 mg/L are limited. This study was designed to generate in-depth pharmacokinetic/pharmacodynamics (PK/PD) understanding of S. aureus isolates inhibited by ≥ 2 mg/L ceftaroline using an in vitro hollow-fibre infection model (HFIM).

Methods

The PK/PD target of ceftaroline was investigated against 12 diverse characterized clinical MRSA isolates with ceftaroline MICs of 2 or 4 mg/L using q8h dosing for 24 h. These isolates carried substitutions in the penicillin-binding domain (PBD) and/or the non-PBD. Additionally, PD responses of mutants with ceftaroline MICs ranging from 2 to 32 mg/L were evaluated against the mean 600 mg q8h human-simulated dose over 72 h.

Results

The mean stasis, 1 log10-kill and 2 log10-kill PK/PD targets were 29%, 32% and 35% f T>MIC, respectively. In addition, these data suggest that the PK/PD target for MRSA is not impacted by the presence of substitutions in the non-PBD commonly found in isolates with ceftaroline MIC values of ≤ 2 mg/L. HFIM studies with 600 mg q8h dosing demonstrated a sustained long-term bacterial suppression for isolates with ceftaroline MICs of 2 and 4 mg/L.

Conclusions

Overall, efficacy was demonstrated against a diverse collection of clinical isolates using HFIM indicating the utility of 600 mg ceftaroline fosamil for S. aureus isolates with MIC ≤4 mg/L using q8h dosing.

Abstract B112: Synergistic anti-lymphoma activity of ibrutinib and dual mTORC1/2 inhibitors in diffuse large B cell lymphoma is maintained in vivo on an intermittent schedule

Diffuse large B cell lymphoma (DLBCL) is the most common type of aggressive non Hodgkins lymphoma. The Activated B-Cell (ABC) subtype of DLBCL is driven by chronic active BCR signaling and remains the most difficult to treat. Resistant ABC-DLBCL occurs in as many as 40% of patients following treatment with R-CHOP. To identify additional treatment options, we performed a combination screen in DLBCL cell lines using a panel of drugs known to target survival and proliferation pathways in DLBCL, and uncovered a drug combination with highly synergistic activity that included the BTK inhibitor, ibrutinib, with the dual mTORC1/2 inhibitor, AZD2014. Ibrutinib is known to have activity in ABC-DLBCL; in a recent Phase I/II clinical trial of relapsed/refractory ABC-DLBCL, ibrutinib treatment resulted in 55% response rate in patients with B cell receptor mutations (Wilson et al, Nature Medicine 2015). In ABC-DLBCL cell lines, combination of AZD2014 with ibrutinib resulted in cell death, induction of cleaved caspase 3, and potent inhibition of c-myc and p-4EBP1. In vivo, combination of ibrutinib with AZD2014 was well tolerated and resulted in potent anti-tumor activity in OCI-Ly10 that was greater than either agent alone, with greater than 100% tumor growth inhibition as well as synergistic inhibition of p-4EBP1 (Ezell et al, Oncotarget 2014). This work was evaluated using a continuous daily dosing schedule of AZD2014 and ibrutinib. More recently, both continuous and intermittent dosing schedules (2 days on, 5 off) have been explored in patients with other solid tumours and was found to be better tolerated. We evaluated an intermittent schedule of AZD2014 in our preclinical ABC-DLBCL model, OCI-Ly10, in combination with ibrutinib and demonstrated that the synergistic combination activity was maintained, with 60% regression compared to only 36% regression with the daily dosing schedule combination. In addition to p-4EBP1 inhibition, we also observed synergistic inhibition of p-pRAS40, p-AKT, p-NDRG1, c-myc, survivin and HMGSC1. Ongoing preclinical work is focused on understanding whether more significant suppression of relevant pathways was achieved with intermittent compared to continuous dosing. Collectively, our data support a rationale for combining BTK and dual mTORC1/2 inhibitors for an effective and alternative treatment option in ABC-DLBCL.

Citation Format: Theresa Proia, Nanhua Deng, Urzsula Polanska, Deborah Lawson, Vasu Sah, Maryann San Martin, Corinne Reimer, Sabina Cosulich. Synergistic anti-lymphoma activity of ibrutinib and dual mTORC1/2 inhibitors in diffuse large B cell lymphoma is maintained in vivo on an intermittent schedule. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B112.

Measurement of the Lambdab0 lifetime in Lambdab0 --> Lambdac+pi- decays in pp collisions at square root of s = 1.96 TeV

We report a measurement of the lifetime of the Lambda(b)(0) baryon in decays to the Lambda(c)(+)pi(-) final state in a sample corresponding to 1.1 fb(-1) collected in pp collisions at square root of s = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Lambda(b)(0) events we measure tau(Lambda(b)(0)) = 1.401 +/- 0.046(stat) +/- 0.035(syst) ps (corresponding to ctau(Lambda(b)(0)) = 420.1 +/- 13.7(stat) +/- 10.6(syst) microm, where c is the speed of light). The ratio of this result and the world average B(0) lifetime yields tau(Lambda(b)(0))/tau(B(0)) = 0.918 +/- 0.038 (stat) and (syst), in good agreement with recent theoretical predictions.

Generation and characterization of an immunogenic dendritic cell population

Dendritic cells (DCs) capture, internalize and process antigens leading to the induction of antigen-specific immune responses. The aim of this study was to develop, implement and characterize an efficient approach for DC-based immunization. Dendritic cells were expanded in vivo by hydrodynamic delivery of a human flt3 ligand expression plasmid. Splenic DCs were isolated and purified with magnetic beads linked to hepatitis C virus (HCV) nonstructural protein-5 (NS5), anti-CD40 and/or LPS. The DCs that contained beads were purified by passage over a magnetic column and subsequently phenotyped. Enrichment resulted in a population consisting of 80% CD11c(+) cells. Uptake of uncoated microparticles promoted DC maturation and the expression of CD80, CD86, and MHC-II molecules; beads coated with LPS and anti-CD40 further increased the expression of these co-stimulatory molecules, as well as the secretion of IL-12. Mice immunized subcutaneously with DCs containing beads coated with HCV NS5 protein, anti-CD40 and LPS exhibited significant antigen-specific, increases in IFN-gamma-producing CD4(+) T cells and CTL activity. This approach combines three critical elements necessary for efficient DC-based immunization that include DC enrichment, maturation and antigen targeting.

Alveolar distraction osteogenesis: a systematic review

This literature review was performed to analyse the outcomes of clinical studies of alveolar distraction osteogenesis (DO) listed by PUBMED between January 1996 and December 2006. A PUBMED search identified 128 articles on alveolar DO. Twenty articles covering 209 cases were analysed, considering location, device and procedural parameters, rate of augmentation, aspect of final implant placement and follow up. The mean latency period was 7.26+/-2.31 days, distraction rate 0.71+/-0.27 mm/day, rate of augmentation 6.88+/-2.52 mm and consolidation period 12.22+/-5.58 weeks. A total of 469 implants were placed and followed post loading for an average of 14.19+/-11.03 months, with a survival rate of 97%. Of the different procedural parameters, only the difference between mean consolidation period for failed (8.10+/-2.51 weeks) and successful (12.43+/-5.62 weeks) implants was statistically significant (P=0.01). Use of DO may be advantageous in terms of the success rate of implants placed in augmented sites, but there is still a lack of sufficient data based on long-term follow up. Future experimental studies should evaluate the application of different methods with a view to shortening the overall treatment period and improving the performance of implants placed in distracted alveolar ridges.

Maternal protein restriction leads to hyperinsulinemia and reduced insulin-signaling protein expression in 21-mo-old female rat offspring

Human adult diseases such as cardiovascular disease, hypertension, and type 2 diabetes have been epidemiologically linked to poor fetal growth and development. Male offspring of rat dams fed a low-protein (LP) diet during pregnancy and lactation develop diabetes with concomitant alterations in their insulin-signaling mechanisms. Such associations have not been studied in female offspring. The aim of this study was to determine whether female LP offspring develop diabetes in later life. Control and LP female offspring groups were obtained from rat dams fed a control (20% protein) or an isocaloric (8% protein) diet, respectively, throughout pregnancy and lactation. Both groups were weaned and maintained on 20% normal laboratory chow until 21 mo of age when they underwent intravenous glucose tolerance testing (IVGTT). Fasting glucose was comparable between the two groups; however, LP fasting insulin was approximately twofold that of controls (P < 0.02). Glucose tolerance during IVGTT was comparable between the two groups; however, LP peak plasma insulin at 4 min was approximately threefold higher than in controls (P < 0.001). LP plasma insulin area under the curve was 1.9-fold higher than controls (P < 0.02). In Western blots, both muscle protein kinase C-zeta expression and p110beta-associated p85alpha in abdominal fat were reduced (P < 0.05) in LPs. Hyperinsulinemia in response to glucose challenge coupled with attenuation of certain insulin-signaling molecules imply the development of insulin resistance in LP muscle and fat. These observations suggest that intrauterine protein restriction leads to insulin resistance in females in old age and, hence, an increased risk of type 2 diabetes.

Four patients with both thrombotic thrombocytopenic purpura and autoimmune thrombocytopenic purpura: the concept of a mixed immune thrombocytopenia syndrome and indications for plasma exchange

Autoimmune thrombocytopenic purpura (ATP) and thrombotic thrombocytopenic purpura (TTP) are each well recognized clinical syndromes which may appear as single episodes or may have chronic relapsing courses. We present four patients negative for human immunodeficiency virus (HIV) infection who appear to have both diagnoses with either concomitant or intermingled episodes, and we review seven additional patients reported in the literature with similar features. All four of our patients are female, two have underlying connective tissue disorders, and their ATP processes came to our attention because of incomplete response of the platelet count to plasma exchange therapy (PEX) during a TTP phase (Cases 1 and 2) or development of thrombocytopenia in the absence of microangiopathy on the background of prior typical TTP episodes (Cases 3 and 4). Recognition of the ATP diagnosis in each case resulted in discontinuation of PEX (Cases 1 and 2) or not instituting PEX (Cases 3 and 4). In each instance, a satisfactory rise in platelet count followed treatment for ATP. Based upon this experience, we conclude that some individuals may have a mixed immune thrombocytopenia syndrome; careful analysis of the mechanism of thrombocytopenia, especially in recurrent episodes and in patients who respond incompletely to PEX for TTP, is important when deciding whether to initiate or continue PEX, or to consider therapies appropriate for other mechanisms of thrombocytopenia.

Identification of E2F-1/Cyclin A antagonists

A simple method for the synthesis of a rationally designed (S,S)-[Pro-Leu]-spirolactam scaffold is described. This was expanded to a small biased library of compounds mimicking the 'ZRXL' motif in order to identify E2F-1/Cyclin A antagonists. The synthesized compounds were evaluated in an E2F-1/Cyclin A binding assay and moderately active analogues were identified. In addition, the critical roles of Phe, Leu, Lys, and Arg residues of the identified motif were determined.

Pell-Gregory classification is unreliable as a predictor of difficulty in extracting impacted lower third molars

We present a study of 166 extractions of impacted lower third molars, all vertical and all extracted by the same surgeon. Each tooth was classified according to the Pell-Gregory scales of position for the occlusal plane (scale A-C) and the ascending ram us of the mandible (scale 1-3). The extraction was subsequently rated as 'easy' or 'difficult'.Taking Pell-Gregory class C as a predictor of a 'difficult' extraction, specificity was 88% but sensitivity was low at 15%. Taking Pell-Gregory class 3 as an indicator of 'difficult', sensitivity was somewhat better (50%), but at the expense of specificity (62%). Likelihood ratios for the individual classes also indicated that the scales are of little value for predicting a difficult extraction.

Selective killing of transformed cells by cyclin/cyclin-dependent kinase 2 antagonists

Recent studies identified a short peptide motif that serves as a docking site for cyclin/cyclin-dependent kinase (cdk) 2 complexes. Peptides containing this motif block the phosphorylation of substrates by cyclin A/cdk2 or cyclin E/cdk2. Here we report that cell membrane-permeable forms of such peptides preferentially induced transformed cells to undergo apoptosis relative to nontransformed cells. Deregulation of E2F family transcription factors is a common event during transformation and was sufficient to sensitize cells to the cyclin/cdk2 inhibitory peptides. These results suggest that deregulation of E2F and inhibition of cdk2 are synthetically lethal and provide a rationale for the development of cdk2 antagonists as antineoplastic agents.

Structural and conformational requirements for high-affinity binding to the SH2 domain of Grb2(1)

Following earlier work on cystine-bridged peptides, cyclic phosphopeptides containing nonreducible mimics of cystine were synthesized that show high affinity and specificity toward the Src homology (SH2) domain of the growth factor receptor-binding protein (Grb2). Replacement of the cystine in the cyclic heptapeptide cyclo(CYVNVPC) by D-alpha-acetylthialysine or D-alpha-lysine gave cyclo(YVNVP(D-alpha-acetyl-thiaK)) (22) and cyclo(YVNVP(D-alpha-acetyl-K)) (30), which showed improved binding 10-fold relative to that of the control peptide KPFYVNVEF (1). NMR spectroscopy and molecular modeling experiments indicate that a beta-turn conformation centered around YVNV is essential for high-affinity binding. X-ray structure analyses show that the linear peptide 1 and the cyclic compound 21 adopt a similar binding mode with a beta-turn conformation. Our data confirm the unique structural requirements of the ligand binding site of the SH2 domain of Grb2. Moreover, the potency of our cyclic lactams can be explained by the stabilization of the beta-turn conformation by three intramolecular hydrogen bonds (one mediated by an H2O molecule). These stable and easily accessible cyclic peptides can serve as templates for the evaluation of phosphotyrosine surrogates and further chemical elaboration.

Clinically significant gastroesophageal reflux in the at-risk premature neonate: relation to cognitive scores, days in the NICU, and total hospital charges

OBJECTIVE

The principal objective of this retrospective, cohort study was to determine if clinically significant gastroesophageal reflux (GER) would impair the long-term cognitive and motor development of preterm infants. An additional objective was to determine the effects of clinically significant GER on the length of hospital stay and total hospital charges in preterm infants.

STUDY DESIGN

The design was a retrospective, cohort study of 66 preterm infants, followed in the Neonatal Developmental Follow-Up Clinic of The Children's Hospital in Greenville, SC. Thirty-three premature infants with clinically significant GER met the following study criteria: birth dates, 1988 through 1994; lack of gastrointestinal anatomic defects; and lack of acute neurologic injury (defined as no intraventricular hemorrhage greater than Papile's grade I, no periventricular leukomalacia, no seizures, and no history of birth asphyxia). Clinically significant GER was defined as GER associated with moderate to severe apnea (n=29) or GER associated with moderate to severe feeding intolerance (n=4). The study patients were matched as closely as possible with 33 control premature infants for sex (except when twins were used), ethnicity, social risk, gestational age, birth weight, and Apgar scores at 1 and 5 minutes. Social risk was categorized using Hack's Social Risk Scale. Important covariates included apnea, home monitoring, and nasal continuous positive airway pressure.

RESULTS

Neurodevelopmental test scores from 7 months of age through 2 years of age did not show any significant differences between premature infants with clinically significant GER and premature infants with no evidence of clinically significant GER. Total hospital charges were statistically different for the clinically significant GER infants and the nonclinically significant GER infants (median $112,916 versus median $63,928, p=0.01). Total neonatal intensive care unit length of stay measures were statistically different between the two groups (median 53 days versus median 40.5 days, p=0.01).

CONCLUSION

Even though clinically significant GER may pose a substantial medical risk in premature infants, the long-term cognitive consequences appear to be negligible. Nevertheless, those premature infants with clinically significant GER do consume significantly more hospital resources than matched controls. Early diagnosis and intervention may possibly lessen the impact of medical costs and reduce length of hospital stay.

The quality information management program database in South Carolina

BACKGROUND

The Quality Information Management (QIM) Program was initiated in 1987 on the basis of the decision of the South Carolina Hospital Association's Subcommittee on Quality Assurance to develop a statewide database that could provide member hospitals with comparative quality indicator data. There are ten indicators for acute care and seven for psychiatry and substance abuse. Thirty-seven acute care hospitals participate in the QIM program, as do 7 specialty hospitals. For each three-month period, participant hospitals complete a computerized software report from their data sources specifying summary-level and patient-level data elements.

REPORTING OF DATA

Participating hospitals are provided detailed, quantitative statistical reports to help them identify variations for further investigation. Risk adjustment is accomplished by peer grouping. Each hospital receives summary data for the peer groups to which it is assigned. During the quarterly users group meetings, participants discuss their successes and failures in collecting, reporting, and presenting indicator data.

DISCUSSION

Involvement in the QIM program has educated participants in the use of comparative databases for quality improvement activities. It is a challenge to help providers and practitioners, in the face of increasing demands for dissemination, become more comfortable with the release of data to the public, while still preserving some degree of confidentiality.

Metered-dose inhaler technique of patients in an urban ED: prevalence of incorrect technique and attempt at education

The metered-dose inhaler (MDI) techniques of 125 asthma patients who presented to a county hospital emergency department (ED) were evaluated. Correct technique was divided into 7 steps. Twenty-one percent of the patients performed all 7 steps correctly. Mean number of steps +/- SD performed correctly was 4.8 +/- 1.7. Verbal individualized instruction was used to improve the technique of patients whose technique was less than perfect. The instruction required a mean +/- SD of 8.3 +/- 5.8 minutes (range, 0 to 30) for all 7 steps to be done correctly at least once. All patients were able to perform all steps correctly after instruction. The amount of time required for teaching was proportional to the number of steps performed incorrectly. The Vitalograph Aerosol Inhalation Monitor was used to verify correct patient technique and as a teaching aid with variable success. Education in proper use of the MDI is important in the overall care of the asthma patient; however, instruction requires a definite time commitment and may not be feasible for all patients in a busy ED. For some patients, alternatives that require less lengthy instruction, such as the use of breath-actuated devices, spacers, and reservoirs, may be required.

T-Cell co-stimulation by the CD28 ligand B7 is involved in the immune response leading to rejection of a spontaneously regressive tumor

Cell variants from experimental tumors may lose their tumorigenicity or give rise to tumors that regress after a short period of progression in immunocompetent syngeneic animals. Rejection of these tumor cells is often T-cell-dependent. It has recently been reported that, besides the specific signal delivered through the clonogenic receptor, T-cell activation requires a co-stimulatory signal, delivered through its CD28 receptor by B7-1 and/or B7-2 molecules expressed at the surface of the antigen-presenting cells. CTLA4Ig, a fusion molecule that specifically inhibits B7-1 and B7-2 binding to their receptors of T cells, was used to investigate the role of B7 in the spontaneous regression of the tumors induced in syngeneic rats by REGb cells, a regressor cell line established from a chemically induced colon carcinoma. When rats received either 1 or 3 CTLA4Ig injections, REGb tumors grew 3 or 7 times larger than in control animals, respectively. However, in most animals, single or repeated CTLA4Ig injections delayed rather than suppressed REGb tumor rejection. Antibodies to CTLA4Ig appeared in treated rats and could explain this transient effect. Neither REGb cells nor freshly isolated MHC class-II+ antigen-presenting cells infiltrating REGb tumors expressed B7, establishing that the target of CTLA4Ig was not located inside the tumor. In contrast, MHC class-II+ B7+ accessory cells were found in the tissue, rather than the tumor itself, was the site of tumor-antigen presentation to tumor-specific T cells. These results establish the role of B7/CD28 co-stimulation pathway in the control of a spontaneously regressive tumor.

Bioelectrical impedance as a discriminator of pressure ulcer risk

In an effort to identify objective measures of tissue structure and function associated with pressure ulcer risk, bioelectrical impedance analysis (BIA) was measured in three progressively larger zones over the trochanter and coccyx in patients assessed at high risk for pressure ulcers (HR group) and age-matched normal controls (CONT group). Local BIA measures were significantly lower in the HR group for each individual site and zone (p < .01). Full-thickness tissue biopsies obtained from each measurement zone did not differ between groups. However, additional nutritional and metabolic parameters were significantly different (p < or = .05). These results suggest that local BIA may be useful in assessing pressure ulcer risk.

Day-night differences in the effects of gonadal hormones on melatonin release from perifused rat pineals. Evidence of a circadian control

The effects of testosterone (10(-3) M, 10(-6) M, and 10(-9) M) and 17 beta-estradiol (10(-3) M and 10(-9) M) were looked for upon isoproterenol-stimulated melatonin release by perifused pineal glands removed from male rats and female rats in diestrus. Two different times of a 12/12 hour light/dark cycle, i.e., 7 and 19 hours after light onset, were documented in order to look for the existence of a circadian stage-dependence of the hormone effects. Both testosterone (45-60%) and estradiol (60-80%) markedly increased melatonin release by glands removed during the dark span and not during the light span. These results show a direct effect of gonadal hormones on pineal melatonin release and strongly suggest a time-related effect of these hormones on pineal function.

Detection of transjugular intrahepatic portosystemic shunt dysfunction: value of duplex Doppler sonography

OBJECTIVE

Recent reports have shown that a high percentage of patients with transjugular intrahepatic portosystemic shunts (TIPS) have postprocedural shunt complications, including thrombosis of the stent, stenosis of the stent, or stenosis of the hepatic vein draining the stent. We did a prospective study to determine the utility of Doppler sonography as a screening technique for the detection of these complications.

SUBJECTS AND METHODS

From September 1991 to September 1992 we placed TIPS in 45 patients. After the procedure, patients were routinely evaluated with both Doppler sonography and angiography. The sonographic protocol consisted of insonation of the stent, portal vein, and hepatic vein to determine the presence of flow, peak velocity, and direction of flow. The angiograms were evaluated for stenoses of the stent or hepatic vein that caused an increase in the portosystemic pressure gradient greater than 15 mm Hg, increased intrahepatic portal venous filling, retrograde filling of the draining hepatic vein, or opacification of varices. The sonographic findings were statistically evaluated to determine if sonography could demonstrate the complications shown by angiography.

RESULTS

Adequate follow-up was obtained in 29 of the 45 patients. Sixteen of the 29 patients had shunt complications that consisted of one stent thrombosis, three stent stenoses, nine hepatic vein stenoses, and three concomitant stenoses of the stent and hepatic vein. Flow was not detected by sonography in the stent of the patient with thrombosis. There was a significant difference (p = .003) between the temporal change in peak stent velocity in patients with stenoses versus those without. Use of a change (increase or decrease) in peak stent velocity greater than 50 cm/sec from the post-TIPS baseline sonogram as the diagnostic criterion for the detection of shunt stenoses resulted in a 93% sensitivity and 77% specificity. Five patients with stenosis had reversed flow in the draining hepatic vein. Only one patient with a stenosis had a peak stent velocity less than 50 cm/sec.

CONCLUSION

Our results suggest that Doppler sonography is an excellent noninvasive screening technique for the detection of complications of TIPS. We have found a temporal change in peak stent velocity greater than 50 cm/sec to be a more sensitive sonographic sign of TIPS stenosis than the previously reported low-velocity parameters. Our experience suggests that nearly all complications of TIPS can be detected by using three criteria: (1) no flow for thrombosis, (2) a temporal change in peak stent velocity greater than 50 cm/sec for stent and/or hepatic vein stenosis, and (3) reversed flow in the hepatic vein draining the stent for hepatic vein and, rarely, stent stenosis.

In vivo and in vitro invasiveness of a rat colon-cancer cell line maintaining E-cadherin expression: an enhancing role of tumor-associated myofibroblasts

In various cell systems, an inverse relationship was found between expression of E-cadherin, a molecule involved in the Ca(2+)-dependent homophylic cell-to-cell attachment of epithelial cells, and the capacity to invade extracellular matrix gels or normal tissues in vitro. DHD/K12/TRb (PROb) cells, maintained as a cell line derived from a rat colon carcinoma, homogeneously expressed in vitro immunoreactive E-cadherin, which was functional as shown in cell dissociation-reassociation assays. PROb cells were found to be non-invasive in 3 different assays in vitro. However, tumors resulting from a s.c. injection of PROb cells into syngeneic BD-IX rats were invasive, although PROb cells maintained E-cadherin expression in the tumors. Cells from a freshly dissociated PROb tumor showed, not only PROb cells but also tumor-associated myofibroblasts and were able to cross a Matrigel-coated filter. PROb tumors were indeed infiltrated by numerous myofibroblasts, mainly located at the invasive edge of the tumor. Cells from an established culture of tumor-infiltrating myofibroblasts were able to confer upon PROb cells invasiveness through Matrigel-coated filter or into chick-heart fragments. PROb cells maintained their capacity to express E-cadherin after myofibroblast-enhanced Matrigel invasion. Tumor-associated myofibroblasts, but not PROb cells, secreted a 72-kDa collagenase that could play a role in tumor-cell invasion. These results strongly suggest that cells from the tumor stroma, and more specifically myofibroblasts, may be involved in the invasiveness of epithelial tumor cells in vivo, even when E-cadherin expression prevents tumor-cell invasiveness in different in vitro assays.

Growth characteristics and metastatic potential of seven intestinal carcinoma lines serially passaged in syngeneic rats

Transplantable tumour lines were obtained from one duodenal carcinoma induced by N-methyl-N'-nitro-N-nitrosoguanidine in the Lewis rat and from six colonic carcinomas induced by 1,2 dimethylhydrazine in BDIX or Fisher rats. The tumours were serially transplanted by the subcutaneous route into homologous syngeneic rats. The seven tumours differ from one another in their histological structure, five of them being well or moderately differentiated adenocarcinomas, and in their capacity to produce neutral or acidic mucins. The seven tumours also differ in their growth rate. The seven lines produced metastases; the metastatic potential and the location of the metastases differed from one line to another. The seven lines kept their original differentiation characteristics through multiple passages, representing several years of transplantation into syngeneic hosts. These tumours represent a useful and diversified model of metastatic intestinal carcinoma, available for basic research and therapeutic trials.

Effects of cyclosporin A on progressive and regressive tumors induced by two cancer lines derived from a single colon carcinoma chemically induced in the rat

The effects of cyclosporin-induced immunosuppression were assessed in a rat model of progressive and regressive colonic tumors. Two cloned cell variants, obtained from the same chemically induced colonic carcinoma, differ in their capacity to grow when injected into the syngeneic rat. PROb cells yield progressive tumors and often metastases; in contrast, REGb cells produce tumors which regress in 3 to 6 weeks. Cyclosporin A (CsA) administered daily, 20 mg/kg subcutaneously (s.c.) for 30 days after tumor cell inoculation, drastically enhanced the local growth of PROb tumors and increased the number of metastases. It increased the local growth and prevented the regression of REGb tumors which persisted even as long as 8 weeks after the termination of CsA administration and occasionally yielded metastases. CsA prevented the accumulation of inflammatory cells with the T lymphocyte phenotype at the periphery of both PROb and REGb tumors but did not alter the tumor infiltration by macrophages and NK cells. CsA did not modify the natural cytotoxicity of peripheral blood mononuclear cells against PROb and REGb target cells. These results suggest that CsA-induced suppression of T lymphocyte activity may enhance tumor progression and suppress tumor regression in this model.

Use of a specific monoclonal antibody for studying the liver metastatic invasion of a rat colon cancer

A simple model for liver metastasis from colon cancer resulted from the intraportal injection of 2 x 10(7) highly tumorigenic DHD/K12/PROb cells into syngeneic BDIX rats. Early detection and development of cancer invasion were studied by conventional microscopy and immunoenzymatic staining using a specific monoclonal antibody. Metastases developed either from isolated cancer cells early disseminated in sinusoid network or from intraportal microthrombi. An intense immune reaction developed until day 15 after injection but decreased and disappeared at the latest stages of evolution.

Effects of a single injection of anti-asialo GM1 serum on natural cytotoxicity and the growth of a regressive colonic tumor in syngeneic rats

The REGb tumor cell line is a cloned variant of the DHD-K12 cell line, established from a colon carcinoma chemically induced in the rat. Unlike the parent DHD-K12 cell line, or other clones, which give progressive tumors when inoculated to the syngeneic rat, REGb cells produce tumors which regress in 3 to 5 weeks and never cause metastasis. In order to explore the role of natural killer (NK) cells in REGb tumor regression, each rat was given one injection of anti-asialoGM1 (anti-asGM1) serum, a known inhibitor of NK activity. This injection was done 24 hr before REGb cell challenge. This injection significantly depressed the in vitro cytotoxicity of peripheral blood lymphocytes on REGb cells for 2 weeks. REGb tumors grew larger and regressed later in the treated animals than those in the controls. Furthermore, a progressive or recurrent tumor was observed in 4 out of 10 treated rats, giving lung and/or lymph-node metastases in 2 cases. Immuno-histological study of the cells infiltrating the REGb tumors in control and treated animals showed a decrease number of asGM1+ and OX8+ lymphocytes, presumably NK cells, after anti-asGM1 treatment. An increase in number of macrophages was demonstrated in the progressive tumors of treated animals. These results suggest that NK cells play an important role in the initial stage of the regression TSb tumors in untreated syngeneic rats.

An immunohistological study of cells infiltrating progressive and regressive tumors induced by two variant subpopulations of a rat colon cancer cell line

In order to understand the mechanisms leading up to progression or regression, tumors resulting from the s.c. inoculation of progressive or regressive variants of a cell culture established from a chemically-induced rat colonic carcinoma were subjected to sequential histological study. As immunological factors have been previously described in this system of progressive or regressive tumors, special interest was given to inflammatory cells, T and B lymphocytes and macrophages, located inside and outside the tumor. Immunohistological methods using monoclonal or polyclonal antibodies and enzyme histology were performed to identify different populations of infiltrative cells. In both variants of tumors an accumulation of these cells were seen at the periphery of the tumor, surrounding the nodules. In contrast, very few inflammatory cells, macrophages or T lymphocytes were seen inside the clumps of tumor cells where cytolytic cells could have a contact-dependent tumoricidal effect. Only small differences were found between progressive and regressive tumors in the density of the various populations of T helper, T cytotoxic/suppressor, B lymphocytes or macrophages inside or around the tumor nodules. On the other hand, progressive and regressive tumors clearly differ in the relationship between tumor cells and the fibroblastic reaction they induce. Regressive tumors were rapidly encircled by a fibroblastic reaction isolating them from the peripheral tissues. The fibroblastic reaction was less dense around the progressive tumor cells which were able to migrate and invade the periphery. This suggests that immunological factors leading to tumor progression or regression could act indirectly through a control of the fibroblastic reaction, rather than through a direct cytotoxic effect on the tumor cells.

Serial hemodynamic assessment of aortobifemoral bypass

Clinical, arteriographic, and vascular diagnostic laboratory (VDL) data on 157 patients undergoing aortobifemoral bypass (ABF/BP) more than 5 years previously were compared in terms of the perspective provided by noninvasive testing, particularly when performed in the face of superficial femoral artery (SFA) occlusion. To the traditional outcome criteria (operative mortality rate, 3.2%; amputation rate, 1.4%; early patency rate, 98%; and late patency rate, 86%), VDL data added an initial hemodynamic failure rate of 14% and a late deterioration rate of 8%. Those patients with occluded SFAs fared worse in regard to initial patency (94% vs. 100%), initial hemodynamic failure (29% vs. 2%), late deterioration (8.8% vs. 5.4%), and late failure rates (16% vs. 10%), whereas those patients with open SFAs suffered more distal disease progression (11.5% vs. 1.3%). "Prediction" of postoperative ankle/brachial index (ABI) from preoperative thigh/brachial index (TBI) and ABI was 92% accurate for limbs with open SFAs but only 84% for limbs with occluded SFAs; prediction was made with a formula based on proportional transmission and with TBI measured with a regularly sized cuff (best combination). Neither additive transmission formula nor measurement of TBI with a large cuff allowed accurate prediction when the SFA was occluded. No advantage, in terms of initial hemodynamic result or late outcome, could be demonstrated for limited profundaplasty in the absence of significant profunda femoral stenosis and end-to-end vs. end-to-side proximal anastomosis.

Gut-associated lymphoid tissue and 1,2-dimethylhydrazine intestinal tumors in the rat: an histological and immunoenzymatic study

The association between chemically-induced intestinal carcinoma and gut lymphoid patches was studied in 20 male Sprague-Dawley rats 7 months after the first of 16 weekly injections of 1,2 dimethylhydrazine (DMH). The lymphoid patches of DMH-treated rats and of 14 untreated control animals were systematically studied histologically on sections of "swiss-rolled" whole intestine. It was found that 78% of the small-intestine carcinomas and 73% of the colorectal carcinomas were associated with intestinal lymphoid patches. Furthermore, misplaced and often atypical glandular crypts were often found in the parafollicular or interfollicular areas of lymphoid patches, in treated as well as in control animals. These glands could be the origin of the lymphoid-patch-associated carcinoma. Immunohistological staining with monoclonal antibodies (MAbs) against T-lymphocyte antigens or anti-IgM serum labelling B lymphocytes clearly localized early carcinoma and atypical glands in the T-dependent, interfollicular and parafollicular area of lymphoid follicles. An MAb directed against la-antigen stained some well-differentiated carcinomas and some atypical glands found in control rats. On the other hand, lymphoid patches, when not invaded by a carcinoma, were not modified in their number, size, morphology or cellular composition in DMH-treated rats as compared to control animals.

Interaction between two cellular subpopulations of a rat colonic carcinoma when inoculated to the syngeneic host

From a single, chemically-induced rat colonic carcinoma, two subpopulations of tumor cells have been isolated. When injected into syngeneic rats, TR cells give rise to progressive tumors in most of the animals, whereas TS cells give rise to no tumors or to tumors which regress in less than 30 days. TS cells inhibit the growth of TR tumors, whether they are injected before TR cells or simultaneously, at a different site or mixed with the TR cells. Lymph nodes and spleen lymphocytes from animals having rejected TS tumors also inhibit TR-cell growth. On the other hand, TS cells are able to give rise to progressive tumors when they are injected into rats bearing established TR tumors. Lymph nodes and spleen cells of TR tumor-bearing rats are able to enhance TS cell growth. These results suggest that subpopulations of cancer cells contained in the same tumor interact with each other through their effect on the host immune system. The growth of a whole tumor probably depends not only on the growth potential of each constituent subpopulation, but also on the interaction between the subpopulations themselves.

Role of macrophage in the defense against intestinal cancers

The capability of activated macrophages to kill tumor cells in vitro is now well documented. The tumoricidal activation of macrophages against intestinal tumor cells by different agents is described and the main hypothesis on the mechanisms of tumor cell killing in vitro are discussed. These in vitro results suggest that the macrophage can constitute an efficient effector cell in the defense against intestinal tumors. The distribution and ratio of macrophages in normal intestine and intestinal tumors is described. At the moment, potent activators of macrophages studied in vivo on experimental and human intestinal tumors give poor results or even enhance the growth of tumors. Macrophages may also interfere with the specific immune response in two directions by enhancing the immune response or decreasing it by elaboration of mediators such as prostaglandins.

Effect of indomethacin on the growth of colon cancer cells in syngeneic rats

A cell culture line has been established from a colonic tumor induced in a rat by dimethylhydrazine. Indomethacin had no effect on the growth of tumors induced in syngeneic rats by s.c. injection of this cell line. Neither indomethacin, nor prostaglandin E2 modify the growth of this established cell line in vitro or alter its destruction by endotoxin-activated macrophages. Indomethacin has been reported to suppress the growth of colonic tumors induced in rats by various carcinogenic drugs. The difference between these results obtained by others on chemically-induced colon cancer and the data we have obtained with a cell line derived from a similar cancer suggests that cancer cells in established culture may loose their sensitivity to prostaglandins, prostaglandin inhibitors or prostaglandin-dependent effector host cells.