Co-Treatments of Edible Curcumin from Turmeric Rhizomes and Chemotherapeutic Drugs on Cytotoxicity and FLT3 Protein Expression in Leukemic Stem Cells

This study aims to enhance efficacy and reduce toxicity of the combination treatment of a drug and curcumin (Cur) on leukemic stem cell and leukemic cell lines, including KG-1a and KG-1 (FLT3+ LSCs), EoL-1 (FLT3+ LCs), and U937 (FLT3- LCs). The cytotoxicity of co-treatments of doxorubicin (Dox) or idarubicin (Ida) at concentrations of the IC10-IC80 values and each concentration of Cur at the IC20, IC30, IC40, and IC50 values (conditions 1, 2, 3, and 4) was determined by MTT assays. Dox-Cur increased cytotoxicity in leukemic cells. Dox-Cur co-treatment showed additive and synergistic effects in several conditions. The effect of this co-treatment on FLT3 expression in KG-1a, KG-1, and EoL-1 cells was examined by Western blotting. Dox-Cur decreased FLT3 protein levels and total cell numbers in all the cell lines in a dose-dependent manner. In summary, this study exhibits a novel report of Dox-Cur co-treatment in both enhancing cytotoxicity of Dox and inhibiting cell proliferation via FLT3 protein expression in leukemia stem cells and leukemic cells. This is the option of leukemia treatment with reducing side effects of chemotherapeutic drugs to leukemia patients.

Modular Chimeric Antigen Receptor Systems for Universal CAR T Cell Retargeting

The engineering of T cells through expression of chimeric antigen receptors (CARs) against tumor-associated antigens (TAAs) has shown significant potential for use as an anti-cancer therapeutic. The development of strategies for flexible and modular CAR T systems is accelerating, allowing for multiple antigen targeting, precise programming, and adaptable solutions in the field of cellular immunotherapy. Moving beyond the fixed antigen specificity of traditional CAR T systems, the modular CAR T technology splits the T cell signaling domains and the targeting elements through use of a switch molecule. The activity of CAR T cells depends on the presence of the switch, offering dose-titratable response and precise control over CAR T cells. In this review, we summarize developments in universal or modular CAR T strategies that expand on current CAR T systems and open the door for more customizable T cell activity.

Potentiating Oncolytic Virus-Induced Immune-Mediated Tumor Cell Killing Using Histone Deacetylase Inhibition

A clinical oncolytic herpes simplex virus (HSV) encoding granulocyte-macrophage colony-stimulating factor (GM-CSF), talimogene laherparepvec, causes regression of injected and non-injected melanoma lesions in patients and is now licensed for clinical use in advanced melanoma. To date, limited data are available regarding the mechanisms of human anti-tumor immune priming, an improved understanding of which could inform the development of future combination strategies with improved efficacy. This study addressed direct oncolysis and innate and adaptive human immune-mediated effects of a closely related HSV encoding GM-CSF (HSVGM-CSF) alone and in combination with histone deacetylase inhibition. We found that HSVGM-CSF supported activation of anti-melanoma immunity via monocyte-mediated type I interferon production, which activates NK cells, and viral maturation of immature dendritic cells (iDCs) into potent antigen-presenting cells for cytotoxic T lymphocyte (CTL) priming. Addition of the histone deacetylase inhibitor valproic acid (VPA) to HSVGM-CSF treatment of tumor cells increased viral replication, viral GM-CSF production, and oncolysis and augmented the development of anti-tumor immunity. Mechanistically, VPA increased expression of activating ligands for NK cell recognition and induced expression of tumor-associated antigens, supporting innate NK cell killing and CTL priming. These data support the clinical combination of talimogene laherparepvec with histone deacetylase inhibition to enhance oncolysis and anti-tumor immunity.

MAGE-A3 immunotherapeutic as adjuvant therapy for patients with resected, MAGE-A3-positive, stage III melanoma (DERMA): a double-blind, randomised, placebo-controlled, phase 3 trial

BACKGROUND

Despite newly approved treatments, metastatic melanoma remains a life-threatening condition. We aimed to evaluate the efficacy of the MAGE-A3 immunotherapeutic in patients with stage IIIB or IIIC melanoma in the adjuvant setting.

METHODS

DERMA was a phase 3, double-blind, randomised, placebo-controlled trial done in 31 countries and 263 centres. Eligible patients were 18 years or older and had histologically proven, completely resected, stage IIIB or IIIC, MAGE-A3-positive cutaneous melanoma with macroscopic lymph node involvement and an Eastern Cooperative Oncology Group performance score of 0 or 1. Randomisation and treatment allocation at the investigator sites were done centrally via the internet. We randomly assigned patients (2:1) to receive up to 13 intramuscular injections of recombinant MAGE-A3 with AS15 immunostimulant (MAGE-A3 immunotherapeutic; 300 μg MAGE-A3 antigen plus 420 μg CpG 7909 reconstituted in AS01B to a total volume of 0·5 mL), or placebo, over a 27-month period: five doses at 3-weekly intervals, followed by eight doses at 12-weekly intervals. The co-primary outcomes were disease-free survival in the overall population and in patients with a potentially predictive gene signature (GS-positive) identified previously and validated here via an adaptive signature design. The final analyses included all patients who had received at least one dose of study treatment; analyses for efficacy were in the as-randomised population and for safety were in the as-treated population. This trial is registered with ClinicalTrials.gov, number NCT00796445.

FINDINGS

Between Dec 1, 2008, and Sept 19, 2011, 3914 patients were screened, 1391 randomly assigned, and 1345 started treatment (n=895 for MAGE-A3 and n=450 for placebo). At final analysis (data cutoff May 23, 2013), median follow-up was 28·0 months [IQR 23·3-35·5] in the MAGE-A3 group and 28·1 months [23·7-36·9] in the placebo group. Median disease-free survival was 11·0 months (95% CI 10·0-11·9) in the MAGE-A3 group and 11·2 months (8·6-14·1) in the placebo group (hazard ratio [HR] 1·01, 0·88-1·17, p=0·86). In the GS-positive population, median disease-free survival was 9·9 months (95% CI 5·7-17·6) in the MAGE-A3 group and 11·6 months (5·6-22·3) in the placebo group (HR 1·11, 0·83-1·49, p=0·48). Within the first 31 days of treatment, adverse events of grade 3 or worse were reported by 126 (14%) of 894 patients in the MAGE-A3 group and 56 (12%) of 450 patients in the placebo group, treatment-related adverse events of grade 3 or worse by 36 (4%) patients given MAGE-A3 vs six (1%) patients given placebo, and at least one serious adverse event by 14% of patients in both groups (129 patients given MAGE-A3 and 64 patients given placebo). The most common adverse events of grade 3 or worse were neoplasms (33 [4%] patients in the MAGE-A3 group vs 17 [4%] patients in the placebo group), general disorders and administration site conditions (25 [3%] for MAGE-A3 vs four [<1%] for placebo) and infections and infestations (17 [2%] for MAGE-A3 vs seven [2%] for placebo). No deaths were related to treatment.

INTERPRETATION

An antigen-specific immunotherapeutic alone was not efficacious in this clinical setting. Based on these findings, development of the MAGE-A3 immunotherapeutic for use in melanoma has been stopped.

FUNDING

GlaxoSmithKline Biologicals SA.

CEA and NCA Expressed by Colon Carcinoma Cells Affect their Interaction with and Lysability by Activated Lymphocytes

Heterogeneous lysability by interleukin-2 activated lymphocytes (LAK) and other immune effectors was observed in the human colon-carcinoma lines LoVo/Dx, LoVo/H and HT29. The tumor cells with high susceptibility to LAK (LoVo/Dx, HT29) expressed higher amounts of the adhesion molecules ICAMl, LFA3 and NCA/CEA than cells with low LAK sensitivity (LoVo/H). Monoclonal antibodies against these molecules caused a marked reduction of lysis by LAK of LoVo/Dx and HT29. A pool of these antibodies induced a nearly complete inhibition of the LAK lysis of both lines. Treatment of LoVo/Dx with differentiating agents (dimethylformamide and retinoic acid) led to a decreased expression of the adhesion molecules, including NCA, accompanied by increased resistance to LAK-mediated lysis. Moreover, the presence of CEA soluble antigen drastically inhibited the cytotoxic activity of LAK effectors against HT29 and LoVo/Dx cells, in a dose-dependent manner. These data indicate that sensitivity of colon-carcinoma cells to activated lymphocytes depends on the level of expression of adhesion molecules, including CEA and NCA. Given the role of CEA-related antigens in tumor/lymphocyte interaction, soluble CEA, frequently released by colon-carcinoma, may be involved in immunosuppressive effects induced in vivo by tumor cells.

Immunotherapeutic Strategies for Malignant Glioma

BACKGROUND

Despite advances in surgery, radiation therapy, and chemotherapy, only modest improvement has been achieved in the survival of patients with malignant gliomas.

METHODS

The authors review the immunologic aspects of gliomas, potential targets for therapy, and issues surrounding current immunotherapeutic strategies directed against malignant gliomas.

RESULTS

The blood-brain barrier and the purported immunological privilege of the brain are not necessarily insurmountable obstacles to effective immunotherapy for brain tumors. Preclinical studies suggest a number of potential therapeutic avenues. Translational studies offer the prospect of providing substantial new information about immunological trafficking in the nervous system and suggesting the most fruitful approaches to immunotherapy for malignant gliomas.

CONCLUSIONS

More effective adjuvant treatments for malignant gliomas are needed. The applicability of immunological approaches in the treatment of these tumors warrants continued study.

Solitomab, an EpCAM/CD3 bispecific antibody construct (BiTE), is highly active against primary uterine serous papillary carcinoma cell lines in vitro

BACKGROUND

Uterine serous carcinoma is an aggressive form of endometrial cancer that carries an extremely poor prognosis. Solitomab is a novel bispecific single-chain antibody construct that targets epithelial cell adhesion molecule on tumor cells and also contains a CD3 binding region. We evaluated the expression levels of epithelial cell adhesion molecule and the in vitro activity of solitomab against primary uterine serous carcinoma cell lines in vitro and ex-vivo in the ascites of patients with uterine serous carcinoma.

OBJECTIVE

The purpose of this study was to determine the frequency of expression of epithelial cell adhesion molecule on uterine serous carcinoma cell lines and the ability of solitomab to modulate immune responses (T-cell proliferation, activation, cytokine production, and tumor killing) to tumor cells when it is combined with lymphocytes and epithelial cell adhesion molecule-positive cell lines or epithelial cell adhesion molecule-positive ascitic fluid in vitro.

STUDY DESIGN

Epithelial cell adhesion molecule expression was evaluated by flow cytometry in a total of 14 primary uterine serous carcinoma cell lines. Sensitivity to solitomab-dependent cellular-cytotoxicity was tested against a panel of primary uterine serous carcinoma cell lines that express different levels of epithelial cell adhesion molecule in standard 4-hour chromium release assays. The proliferative activity, activation, cytokine secretion (ie, type I vs type II), and cytotoxicity of solitomab in autologous tumor-associated T cells in the ascitic fluid of patients with uterine serous carcinoma was also evaluated by carboxyfluorescein succinimidyl ester and flow-cytometry assays. Differences in epithelial cell adhesion molecule expression, solitomab-dependent cellular-cytotoxicity levels were analyzed with the use of an unpaired t test. T-cell activation marker increase and cytokine release were analyzed by a paired t test.

RESULTS

Surface expression of epithelial cell adhesion molecule was found in 85.7% (12 of 14) of the uterine serous carcinoma cell lines that were tested by flow cytometry. Epithelial cell adhesion molecule-positive cell lines were found resistant to natural killer cells or T-cell-mediated killing after exposure to peripheral blood lymphocytes in 4-hour chromium-release assays (mean killing ± standard of the mean, 2.7% ± 3.1% after incubation of epithelial cell adhesion molecule-positive cell lines with control bispecific antibody construct). In contrast, after incubation with solitomab, epithelial cell adhesion molecule-positive uterine serous carcinoma cells became highly sensitive to T-cell cytotoxicity (mean killing, 25.7% ± 4.5%; P < .0001) by peripheral blood lymphocytes. Ex vivo incubation of autologous tumor-associated lymphocytes with epithelial cell adhesion molecule that expressed malignant cells in ascites with solitomab resulted in a significant increase in T-cell proliferation in both CD4+ and CD8+ T cells, increase in T-cell activation markers (ie, CD25 and HLA-DR), and a reduction in number of viable uterine serous carcinoma cells in ascites (P < .001).

CONCLUSION

Solitomab induces robust immunologic responses in vitro that result in increased T-cell activation, proliferation, production of cytokines, and direct killing of tumor cells. These findings suggest that solitomab may represent a novel, potentially effective agent for the treatment of recurrent/metastatic and/or chemo-resistant uterine serous carcinoma-overexpressing epithelial cell adhesion molecule.

Sulfonamide bearing pyrazolylpyrazolines as potent inhibitors of carbonic anhydrase isoforms I, II, IX and XII

A series of pyrazolylpyrazolines was designed, synthesized and evaluated for carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity against cytosolic human (h) isozymes hCA I and hCA II as well as transmembrane tumor associated isozymes, hCA IX and hCA XII. All the tested compounds exhibited an excellent CA activity profile against hCA I, hCA II and hCA XII when compared to the reference drug acetazolamide (AZA). Compounds 6d, 6f and 7a-7f have exhibited better inhibition profile against hCA XII (Ki = 0.47-5.1 nM) as compared with AZA (Ki = 5.7 nM) especially, compounds 6a, 7a, 7c and 7d which were nearly 10-fold better than reference drug. Against hCA II, all of the tested compounds were better than the standard drug especially compounds 6c, 6d, 7c and 7d (Ki = 1.1-1.7 nM) were many fold better inhibitors than AZA (Ki = 12.1 nM). In addition, they acted as selective CA inhibitors of isoform hCA XII over the physiological isoform hCA I.

Cancer vaccines

Cancer vaccines are designed to promote tumor specific immune responses, particularly cytotoxic CD8 positive T cells that are specific to tumor antigens. The earliest vaccines, which were developed in 1994-95, tested non-mutated, shared tumor associated antigens that had been shown to be immunogenic and capable of inducing clinical responses in a minority of people with late stage cancer. Technological developments in the past few years have enabled the investigation of vaccines that target mutated antigens that are patient specific. Several platforms for cancer vaccination are being tested, including peptides, proteins, antigen presenting cells, tumor cells, and viral vectors. Standard of care treatments, such as surgery and ablation, chemotherapy, and radiotherapy, can also induce antitumor immunity, thereby having cancer vaccine effects. The monitoring of patients' immune responses at baseline and after standard of care treatment is shedding light on immune biomarkers. Combination therapies are being tested in clinical trials and are likely to be the best approach to improving patient outcomes.

An improved high yield total synthesis and cytotoxicity study of the marine alkaloid neoamphimedine: an ATP-competitive inhibitor of topoisomerase IIα and potent anticancer agent

Recently, we characterized neoamphimedine (neo) as an ATP-competitive inhibitor of the ATPase domain of human Topoisomerase IIα. Thus far, neo is the only pyridoacridine with this mechanism of action. One limiting factor in the development of neo as a therapeutic agent has been access to sufficient amounts of material for biological testing. Although there are two reported syntheses of neo, both require 12 steps with low overall yields (≤6%). In this article, we report an improved total synthesis of neo achieved in 10 steps with a 25% overall yield. In addition, we report an expanded cytotoxicity study using a panel of human cancer cell lines, including: breast, colorectal, lung, and leukemia. Neo displays potent cytotoxicity (nM IC50 values) in all, with significant potency against colorectal cancer (lowest IC50 = 6 nM). We show that neo is cytotoxic not cytostatic, and that neo exerts cytotoxicity by inducing G2-M cell cycle arrest and apoptosis.

Therapeutic targeting of integrin αvβ6 in breast cancer

BACKGROUND

Integrin αvβ6 promotes migration, invasion, and survival of cancer cells; however, the relevance and role of αvβ6 has yet to be elucidated in breast cancer.

METHODS

Protein expression of integrin subunit beta6 (β6) was measured in breast cancers by immunohistochemistry (n > 2000) and ITGB6 mRNA expression measured in the Molecular Taxonomy of Breast Cancer International Consortium dataset. Overall survival was assessed using Kaplan Meier curves, and bioinformatics statistical analyses were performed (Cox proportional hazards model, Wald test, and Chi-square test of association). Using antibody (264RAD) blockade and siRNA knockdown of β6 in breast cell lines, the role of αvβ6 in Human Epidermal Growth Factor Receptor 2 (HER2) biology (expression, proliferation, invasion, growth in vivo) was assessed by flow cytometry, MTT, Transwell invasion, proximity ligation assay, and xenografts (n ≥ 3), respectively. A student's t-test was used for two variables; three-plus variables used one-way analysis of variance with Bonferroni's Multiple Comparison Test. Xenograft growth was analyzed using linear mixed model analysis, followed by Wald testing and survival, analyzed using the Log-Rank test. All statistical tests were two sided.

RESULTS

High expression of either the mRNA or protein for the integrin subunit β6 was associated with very poor survival (HR = 1.60, 95% CI = 1.19 to 2.15, P = .002) and increased metastases to distant sites. Co-expression of β6 and HER2 was associated with worse prognosis (HR = 1.97, 95% CI = 1.16 to 3.35, P = .01). Monotherapy with 264RAD or trastuzumab slowed growth of MCF-7/HER2-18 and BT-474 xenografts similarly (P < .001), but combining 264RAD with trastuzumab effectively stopped tumor growth, even in trastuzumab-resistant MCF-7/HER2-18 xenografts.

CONCLUSIONS

Targeting αvβ6 with 264RAD alone or in combination with trastuzumab may provide a novel therapy for treating high-risk and trastuzumab-resistant breast cancer patients.

4-Functionalized 1,3-diarylpyrazoles bearing benzenesulfonamide moiety as selective potent inhibitors of the tumor associated carbonic anhydrase isoforms IX and XII

A library of 4-functionalized 1,3-diarylpyrazoles (3a-3h, 5a-5g and 6a-6g) was designed, synthesized and evaluated against four human carbonic anhydrase (CA, EC 4.2.1.1) isozymes representing two cytosolic isozymes hCA I and hCA II, and two transmembrane tumor associated ones, hCA IX and hCA XII. All the twenty two tested compounds exhibited excellent CA activity profile against the four CA isozymes when compared to the reference drug acetazolamide. Six of the tested compounds (3a-3b, 3f, 3h, 6a and 6b) displayed low nanomolar affinity (Ki < 5 nM) for hCA IX whereas seven compounds (3a-3b, 3d-3f, 3h and 6f) displayed Ki < 10 nM against hCA XII. In addition, they acted as selective CA inhibitors of isoforms IX and XII over the physiological isoforms I and II.

Promising systemic immunotherapies in head and neck squamous cell carcinoma

Patients with head and neck squamous cell carcinoma (HNSCC) demonstrate poor survival and significant treatment morbidity with standard therapy. The immune profile in HNSCC, whether caused by carcinogen exposure or human papillomavirus (HPV), is notably immunosuppressive. Early clinical trials of immunotherapy in HNSCC were troubled by systemic toxicity or difficulties in local administration. Now, interest in immunotherapy has been revitalized by mechanistic insights into immune evasion by HNSCC, coupled to ongoing development of novel immunotherapies. This review will summarize immune escape mechanisms in HNSCC, namely downregulation of tumor antigen (TA) presentation, aberrant regulation of the signal transducer and activator of transcription (STAT) family, the immunosuppressive cytokine milieu, and dysregulation of immune effector cells. Therapeutic strategies hypothesized to specifically counter HNSCC immunosuppression will then be discussed. We will survey TA- targeted monoclonal antibodies (mAb), including the prototype cetuximab, as well as adjunctive strategies to enhance antibody-dependent cell-mediated cytotoxicity. We will review immunomodulation to restore STAT1/STAT3 activation balance. Examples of mAb therapy to block immunosuppressive cytokines, such as interleukin-6 or VEGF, will be provided. mAbs which release co-inhibitory T cell receptors such as CTLA-4 and PD-1, overexpressed in HNSCC, also hold therapeutic promise. Finally, we will describe principles for therapeutic vaccination in HPV-associated HNSCC, where non-host TAs such as viral oncoproteins represent ideal targets, and HPV-negative HNSCC, where p53 is a promising target. Insights into immunosuppression in HNSCC have elucidated mechanistic targets for immunotherapy. Rational clinical investigation may lead to effective stand alone or combinatorial treatment approaches.

(-)-Xanthatin up-regulation of the GADD45γ tumor suppressor gene in MDA-MB-231 breast cancer cells: role of topoisomerase IIα inhibition and reactive oxygen species

Previously, we reported that (-)-xanthatin, a naturally occurring xanthanolide present in the Cocklebur plant, exhibits potent anti-proliferative effects on human breast cancer cells, accompanied by an induction of the growth arrest and DNA damage-inducible gene 45γ (GADD45γ), recognized recently as a novel tumor suppressor gene. However, the mechanisms mediating this activation were unknown. Topoisomerase IIα (Topo IIα) inhibition has been reported to produce a cell death response accompanied by an atypical DNA laddering fragmentation profile, similar to that noted previously for (-)-xanthatin. Therefore we hypothesized that (-)-xanthatin's GADD45γ activation was mediated through the Topo IIα pathway. Here, we identify that (-)-xanthatin does function as a catalytic inhibitor of Topo IIα, promoting DNA damage. In addition, reactive oxygen species (ROS) were elevated in cells treated with this agent. Mechanistically, it was determined that the induced levels of GADD45γ mRNA resulting from (-)-xanthatin exposures were stabilized by coordinately produced ROS, and that the consequent induction of GADD45γ mRNA, GADD45γ protein and ROS generation were abrogated by co-treatment with N-acetyl-l-cysteine. Taken together, the data support the concept that Topo IIα inhibition by (-)-xanthatin is a trigger that stimulates expression of DNA damage-inducible GADD45γ mRNA and that concomitantly produced ROS act downstream to further enhance the GADD45γ mRNA/GADD45γ protein induction process, resulting in breast cancer cell death.

Identification of a novel HLA-A2-restricted mutated Survivin epitope and induction of specific anti-HCC CTLs that could effectively cross-recognize wild-type Survivin antigen

Peptide vaccine based on tumor-associated antigen (TAA), which usually belongs to self-antigen with poor immunogenicity, has been considered as an attractive option for treatment of malignant tumors. The ideal TAA epitopes should have stable affinity to major histocompatibility complex (MHC) molecules and elicit strong anti-tumor immune response. Although point-mutation technology of TAA peptide may increase the binding capability to MHC molecules, some previous studies have revealed that part of the variant peptides results in lymphocyte not to effectively cross-recognize and kill the target tumor expressed wild-type TAA. Here, we designed a novel HLA-A2-restricted mutated TAA Survivin epitope nonapeptide Sur79L2 (KLSSGCAFL) that showed higher binding ability compared to wild-type peptide Sur79 (KHSSGCAFL) in T2-binding assays. To investigate whether Sur79L2 can induce Survivin-specific anti-hepatocellular carcinoma (HCC) response, we stimulated tumor-associated lymphocytes from a HCC patient with Sur79L2 in vitro. IFN-γ release and cytotoxicity assays showed Sur79L2 could effectively cross-recognize and lysis T2 cell plus peptide Sur79 and HCC cell lines (expression of wild-type Survivin antigen) in an HLA-A2-restricted manner. In contrast, peptide Sur95 (ELTLGEFLKL) that has been reported as a very promising anti-tumor epitope in a variety of tumors except HCC were not able to generate detectable cytotoxic immune responses against HCC in this study. Our results suggest that point-mutated peptide Sur79L2 is a new HLA-A2-restricted CTL epitope and may be useful for the immunotherapy for patients with HCC.

Synthesis and SAR of novel Re/99mTc-labeled benzenesulfonamide carbonic anhydrase IX inhibitors for molecular imaging of tumor hypoxia

Carbonic anhydrase IX (CA-IX) is upregulated in cancer in response to the hypoxic tumor microenvironment, making it an attractive molecular target for the detection of hypoxic solid tumors. A series of small molecule benzenesulfonamide based CA-IX inhibitors containing novel tridentate chelates complexed with the M(CO)(3) core (M = Re or (99m)Tc) were designed and synthesized. The in vitro binding affinity of the benzenesulfonamide rhenium complexes yielded IC(50) values ranging from 3 to 116 nM in hypoxic CA-IX expressing HeLa cells. One of the most potent compounds, 3d (IC(50) = 9 nM), was radiolabeled with technetium tricarbonyl ({(99m)Tc(CO)(3)}(+)) to afford the {(99m)Tc(CO)(3)}(+) complex in excellent yield and high purity. (99m)Tc(CO)(3)-3d bound specifically to CA-IX expressing hypoxic HeLa cells. This effort led to the identification of a diverse series of promising high affinity {(99m)Tc(CO)(3)}(+) radiolabeled CA-IX inhibitors with the potential to significantly impact diagnosis, staging, and treatment selection of hypoxic solid tumors.

Sugar-binding proteins from fish: selection of high affinity "lambodies" that recognize biomedically relevant glycans

Glycan-binding proteins are important for a wide variety of basic research and clinical applications, but proteins with high affinity and selectivity for carbohydrates are difficult to obtain. Here we describe a facile and cost-effective strategy to generate monoclonal lamprey antibodies, called lambodies, that target glycan determinants. We screened a library of yeast surface-displayed (YSD) lamprey variable lymphocyte receptors (VLR) for clones that can selectively bind various biomedically important glycotopes. These glycoconjugates included tumor-associated carbohydrate antigens (Tn and TFα), Lewis antigens (LeA and LeX), N-glycolylneuraminic acid, targets of broadly neutralizing HIV antibodies (poly-Man9 and the HIV gp120), and the glycoproteins asialo-ovine submaxillary mucin (aOSM) and asialo-human glycophorin A (aGPA). We isolated clones that bind each of these targets in a glycan-dependent manner and with very strong binding constants, for example, 6.2 nM for Man9 and 44.7 nM for gp120, determined by surface plasmon resonance (SPR). One particular lambody, VLRB.aGPA.23, was shown by glycan array analysis to be selective for the blood group H type 3 trisaccharide (BG-H3, Fucα1-2Galβ1-3GalNAcα), aGPA, and TFα (Galβ1-3GalNAcα), with affinity constants of 0.2, 1, and 8 nM, respectively. In human tissue microarrays this lambody selectively detected cancer-associated carbohydrate antigens in 14 different types of cancers. It stained 27% of non-small cell lung cancer (NSCLC) samples in a pattern that correlated with poor patient survival. Lambodies with exquisite affinity and selectivity for glycans may find myriad uses in glycobiology and biomedical research.

Neoamphimedine circumvents metnase-enhanced DNA topoisomerase IIα activity through ATP-competitive inhibition

Type IIα DNA topoisomerase (TopoIIα) is among the most important clinical drug targets for the treatment of cancer. Recently, the DNA repair protein Metnase was shown to enhance TopoIIα activity and increase resistance to TopoIIα poisons. Using in vitro DNA decatenation assays we show that neoamphimedine potently inhibits TopoIIα-dependent DNA decatenation in the presence of Metnase. Cell proliferation assays demonstrate that neoamphimedine can inhibit Metnase-enhanced cell growth with an IC₅₀ of 0.5 μM. Additionally, we find that the apparent K_m of TopoIIα for ATP increases linearly with higher concentrations of neoamphimedine, indicating ATP-competitive inhibition, which is substantiated by molecular modeling. These findings support the continued development of neoamphimedine as an anticancer agent, particularly in solid tumors that over-express Metnase.

Prognostic potential of topoisomerase IIα and HER2 in a retrospective analysis of early advanced breast cancer patients treated with adjuvant anthracycline chemotherapy

BACKGROUND

After surgery and anthracycline adjuvant treatment, about 60% of early advanced breast cancer patients develop recurrence. These differences in treatment outcome indicate the need to identify markers for risk of recurrence. The aim of this study was the retrospective analysis of relationship between tumour features (topoisomerase IIα (TOPOIIα), human epidermal growth factor receptor 2 (HER2), hormone receptors, cytokeratin (CK)5/6 expression and proliferation rate) and disease-free survival (DFS) of breast cancer patients treated with anthracyclines in adjuvant setting.

MATERIAL AND METHODS

The study was performed in the group of 172 patients (mean age: 52.8 years, T1-T2, N1-N2, M0). HER2, TOPOIIα, estrogen receptor (ER) and progesterone receptor (PgR) expression and proliferation rate were studied immunohistochemically. HER2 overexpression was confirmed by fluorescence in situ hybridisation (FISH). These data were correlated with 5-year DFS.

RESULTS

In univariate analysis, lower TOPOIIα expression (median value ≤ 11.9%) and tumour grade G1 + G2 were favourable prognostic factors. All tumours were classified into four subtypes: (1) lower TOPOIIα expression and G1 + G2, (2) lower TOPOIIα expression and G3, (3) higher TOPOIIα expression and G3, and (4) higher TOPOIIα expression and G1 + G2. In Cox multivariate regression analysis, tumour subtype distinguished by TOPOIIα expression and grade was independent prognostic factor for DFS. All patients (n = 52) with TOPOIIα lower expression and G1 + G2 tumours, survived 5 years without any evidence of disease.

CONCLUSION

The results suggest that lower TOPOIIα expression and lower tumour grade are favourable prognostic factors for early advanced breast cancer patients after adjuvant anthracycline chemotherapy.

Alteration of topoisomerase II-alpha gene in human breast cancer: association with responsiveness to anthracycline-based chemotherapy

PURPOSE

Approximately 35% of HER2-amplified breast cancers have coamplification of the topoisomerase II-alpha (TOP2A) gene encoding an enzyme that is a major target of anthracyclines. This study was designed to evaluate whether TOP2A gene alterations may predict incremental responsiveness to anthracyclines in some breast cancers.

METHODS

A total of 4,943 breast cancers were analyzed for alterations in TOP2A and HER2. Primary tumor tissues from patients with metastatic breast cancer treated in a trial of chemotherapy plus/minus trastuzumab were studied for amplification/deletion of TOP2A and HER2 as a test set followed by evaluation of malignancies from two separate, large trials for changes in these same genes as a validation set. Association between these alterations and clinical outcomes was determined.

RESULTS

Test set cases containing HER2 amplification treated with doxorubicin and cyclophosphamide (AC) plus trastuzumab, demonstrated longer progression-free survival compared to those treated with AC alone (P = .0002). However, patients treated with AC alone whose tumors contain HER2/TOP2A coamplification experienced a similar improvement in survival (P = .004). Conversely, for patients treated with paclitaxel, HER2/TOP2A coamplification was not associated with improved outcomes. These observations were confirmed in a larger validation set, where HER2/TOP2A coamplification was again associated with longer survival when only anthracycline-containing chemotherapy was used for treatment compared with outcome in HER2-positive cancers lacking TOP2A coamplification.

CONCLUSION

In a study involving nearly 5,000 breast malignancies, both test set and validation set demonstrate that TOP2A coamplification, not HER2 amplification, is the clinically useful predictive marker of an incremental response to anthracycline-based chemotherapy. Absence of HER2/TOP2A coamplification may indicate a more restricted efficacy advantage for breast cancers than previously thought.

Treatment of ovarian cancer cell lines with 5-aza-2'-deoxycytidine upregulates the expression of cancer-testis antigens and class I major histocompatibility complex-encoded molecules

PURPOSE

To test the hypothesis that decrease in DNA methylation will increase the expression of cancer-testis antigens (CTA) and class I major histocompatibility complex (MHC)-encoded molecules by ovarian cancer cells, and thus increase the ability of these cells to be recognized by antigen-reactive CD8(+) T cells.

METHODS

Human ovarian cancer cell lines were cultured in the presence or absence of varying concentrations of the DNA demethylating agent 5-aza-2'-deoxycytidine (DAC) for 3-7 days. The expression levels of 12 CTA genes were measured using the polymerase chain reaction. The protein expression levels of class I MHC molecules and MAGE-A1 were measured by flow cytometry. T cell reactivity was determined using interferon-gamma ELISpot analysis.

RESULTS

DAC treatment of ovarian cancer cell lines increased the expression of 11 of 12 CTA genes tested including MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A10, MAGE-A12, NY-ESO-1, TAG-1, TAG-2a, TAG-2b, and TAG-2c. In contrast, DAC treatment decreased the already low expression of the MAGE-A2 gene by ovarian cancer cells, a finding not previously observed in cancers of any histological type. DAC treatment increases the expression of class I MHC molecules by the cells. These effects were time-dependent over a 7-day interval, and were dose-dependent up to 1-3 microM for CTA and up to 10 microM for class I MHC molecules. Each cell line tested had a unique pattern of gene upregulation after exposure to DAC. The enhanced expression levels increased the recognition of 2 of 3 antigens recognized by antigen-reactive CD8(+) T cells.

CONCLUSIONS

These results demonstrate the potential utility of combining DAC therapy with vaccine therapy in an attempt to induce the expression of antigens targeted by the vaccine, but they also demonstrate that care must be taken to target inducible antigens.

NY-BR-1 protein expression in breast carcinoma: a mammary gland differentiation antigen as target for cancer immunotherapy

NY-BR-1 is a recently identified differentiation antigen of the mammary gland. To use NY-BR-1 for T-cell-based immunotherapy, analysis of its co-expression with HLA class I antigens is required. In the present tissue microarray study, primary breast cancers (n = 1,444), recurrences (n = 88), lymph node (n = 525) and distant metastases (n = 91) were studied for NY-BR-1 expression using a novel monoclonal antibody. NY-BR-1 expression was compared with prognosis, estrogen receptor, HER2-status, EGFR and HLA class I antigen expression. NY-BR-1 was more frequently expressed in grade 1 (82%) than in grade 2 (69%) and grade 3 (46%) carcinomas (P < 0.0001). Moreover, NY-BR-1 expression correlated directly with estrogen receptor expression (P < 0.0001) and inversely correlated with HER2-status and EGFR expression (P < 0.0001 for both). Considering high expression level of co-expression, 198/1,321 (15%) primary breast carcinomas and 4/65 (6%) distant metastases expressed NY-BR-1 and HLA class I, suggesting that active immunotherapy can be applied to about 10% of breast cancer patients. Survival analysis showed an association of NY-BR-1 expression with better patient outcome (P = 0.015). No difference between NY-BR-1 expression of primary tumors and metastases could be found, indicating that the presence of NY-BR-1 in metastases can be deduced from their corresponding primary. Forty-three paired biopsies taken from patients before and after chemotherapy suggest that NY-BR-1 expression is not influenced by preceding chemotherapy (kappa = 0.89, P < 0.0001). In summary, the co-expression of NY-BR-1 with HLA class I antigens and its expression in metastases without modification by chemotherapy suggest that NY-BR-1 targeted immunotherapy represents a viable strategy in addition to other targeted cancer drug therapies of breast cancer.

Experience with alemtuzumab in treatment of chronic lymphocytic leukaemia in the Netherlands

BACKGROUND

Alemtuzumab (MabCampath) is a monoclonal antibody against CD52, indicated as third-line treatment of chronic lymphocytic leukaemia (CLL). As most important side effect opportunistic infections are mentioned. It is, however, unknown whether these complications often lead to problems in general patient care in the Netherlands.

METHODS

To gain insight into the use and complications of alemtuzumab therapy, the alemtuzumab-treated CLL patients in 15 hospitals in the Netherlands were evaluated by means of a questionnaire.

RESULTS

In the period from 31 October 2001 until 17 November 2005, 27 patients with CLL or prolymphocytic leukaemia (PLL), RAI stage I to IV, Binet stage A to C, received 32 treatments with alemtuzumab. The time from diagnosis until start of alemtuzumab treatment was 6 +/- 4.5 years (mean +/- SD ). The treatment lasted 11 +/- 7 weeks. Of the treatments, 41% could be administered for the full 12 weeks. The most frequent adverse events were fever (72%), shivering (47%), fatigue (22%) and dyspnoea (16%). Haematological side effects consisted of leucopenia (75%), thrombocytopenia (44%), and anaemia (13%). Infectious complications occurred in 12 of 32 (38%) treatments: pneumonia (25%; of which one Pneumocystis carini pneumonia and four Aspergillus infections), sepsis (9%; of which one Listeria), herpes zoster (9%), herpes simplex (6%), CMV reactivation (6%), meningitis (3%) and Guillain Barre (3%). The overall response was 53%, with complete remission in 13%, partial remission in 41%, stable disease in 25% and progressive disease in 13%, and lasted for 8.3 +/- 7.3 months.

CONCLUSION

Treatment with alemtuzumab is often terminated prematurely, leading to a suboptimal treatment effect. Fear of severe uncontrollable opportunistic infections seems unjustified.

Monoclonal antibodies to six-transmembrane epithelial antigen of the prostate-1 inhibit intercellular communication in vitro and growth of human tumor xenografts in vivo

Six-transmembrane epithelial antigen of the prostate-1 (STEAP-1) is a novel cell surface protein highly expressed in primary prostate cancer, with restricted expression in normal tissues. In this report, we show STEAP-1 expression in prostate metastases to lymph node and bone and in the majority of human lung and bladder carcinomas. We identify STEAP-1 function in mediating the transfer of small molecules between adjacent cells in culture, indicating its potential role in tumor cell intercellular communication. The successful generation of two monoclonal antibodies (mAb) that bind to cell surface STEAP-1 epitopes provided the tools to study STEAP-1 susceptibility to naked antibody therapy. Both mAbs inhibited STEAP-1-induced intercellular communication in a dose-dependent manner. Furthermore, both mAbs significantly inhibited tumor growth in mouse models using patient-derived LAPC-9 prostate cancer xenografts and established UM-UC-3 bladder tumors. These studies validate STEAP-1 as an attractive target for antibody therapy in multiple solid tumors and provide a putative mechanism for mAb-induced tumor growth inhibition.

Carbonic anhydrase inhibitors: X-ray and molecular modeling study for the interaction of a fluorescent antitumor sulfonamide with isozyme II and IX

The X-ray crystal structure of the fluorescent antitumor sulfonamide carbonic anhydrase (CA, EC, 4.2.1.1) inhibitor (4-sulfamoylphenylethyl)thioureido fluorescein (1) in complex with the cytosolic isoform hCA II is reported, together with a modeling study of the adduct of 1 with the tumor-associated isoform hCA IX. Its binding to hCA II is similar to that of other benzesulfonamides, with the ionized sulfonamide coordinated to the Zn2+ ion within the enzyme active site, and also participating in a network of hydrogen bonds with residues Thr199 and Glu106. The scaffold of 1 did not establish polar interactions within the enzyme active site but made hydrophobic contacts (<4.5 A) with Gln92, Val121, Phe131, Val135, Leu198, Thr199, Thr200, and Pro202. The substituted 3-carboxy-amino-phenyl functionality was at van der Waals distance from Phe131, Gly132, and Val135. The bulky tricyclic fluorescein moiety was located at the rim of the active site, on the protein surface, and strongly interacted with the alpha-helix formed by residues Asp130-Val135. All these interactions were preserved in the hCA IX-1 adduct, but the carbonyl moiety of the fluorescein tail of 1 participates in a strong hydrogen bond with the guanidine moiety of Arg130, an amino acid characteristic of the hCA IX active site. This may account for the roughly 2 times higher affinity of 1 for hCA IX over hCA II and may explain why in vivo the compound specifically accumulates only in hypoxic tumors overexpressing CA IX and not in the normal tissues. The compound is in clinical studies as an imaging tool for acute hypoxic tumors.

A mouse model for studying the interaction of bisdioxopiperazines with topoisomerase IIalpha in vivo

The bisdioxopiperazines such as (+)-(S)-4,4'-propylenedi-2,6-piperazinedione (dexrazoxane; ICRF-187), 1,2-bis(3,5-dioxopiperazin-1-yl)ethane (ICRF-154), and 4,4'-(1,2-dimethyl-1,2-ethanediyl)bis-2,6-piperazinedione (ICRF-193) are agents that inhibit eukaryotic topoisomerase II, whereas their ring-opened hydrolysis products are strong iron chelator. The clinically approved analog ICRF-187 is a pharmacological modulator of topoisomerase II poisons such as etoposide in preclinical animal models. ICRF-187 is also used to protect against anthracycline-induced cardiomyopathy and has recently been approved as an antidote for alleviating tissue damage and necrosis after accidental anthracycline extravasation. This dual modality of bisdioxopiperazines, including ICRF-187, raises the question of whether their pharmacological in vivo effects are mediated through interaction with topoisomerase II or via their intracellular iron chelating activity. In an attempt to distinguish between these possibilities, we here present a transgenic mouse model aimed at identifying the contribution of topoisomerase IIalpha to the effects of bisdioxopiperazines. A tyrosine 165 to serine mutation (Y165S) in topoisomerase IIalpha, demonstrated previously to render the human ortholog of this enzyme highly resistant toward bisdioxopiperazines, was introduced at the TOP2A locus in mouse embryonic stem cells by targeted homologous recombination. These cells were used for the generation of transgenic TOP2A(Y165S/+) mice, which were demonstrated to be resistant toward the general toxicity of both ICRF-187 and ICRF-193. Hematological measurements indicate that this is most likely caused by a decreased ability of these agents to induce myelosuppression in TOP2A(Y165S/+) mice, highlighting the role of topoisomerase IIalpha in this process. The biological and pharmacological implications of these findings are discussed, and areas for further investigations are proposed.

Integration of novel targeted therapies into the systemic treatment of breast cancer--a review

Over the last few years it has been anticipated that molecularly targeted agents can provide substantial improvement in the treatment of breast cancer. The most illustrative paradigm has been that of trastuzumab (Herceptin), a humanized monoclonal antibody against the HER2 oncoprotein overexpressed in 25% of breast cancers. Trastuzumab when combined with standard cytotoxic chemotherapy improved the outcome and survival in patients with metastatic breast cancer, whereas, over the last 2 years studies incorporating trastuzumab in sequence to or concurrently with taxane-based chemotherapy in the adjuvant setting demonstrated a considerable benefi t in this subset, with the results of longer follow-up regarding long-term outcome and late toxicities expected over the forthcoming years. Moreover, the prognostic and predictive value of topoisomerase IIa (Topo IIa) overexpression in these subgroups with respect to anthracycline treatment has been extensively discussed and analysed. Other inhibitors of both HER1/HER2 have recently been introduced with promising results and results of ongoing studies are awaited with great interest. A recently anticipated target in advanced breast cancer has been the pathway of angiogenesis; first a humanized monoclonal antibody-bevacizumab (Avastin)- has demonstrated encouraging results when combined with chemotherapy in pretreated HER2-negative advanced breast cancer, while combinations with trastuzumab+/-chemotherapy are currently examined in HER2-overexpressing breast cancer. Furthermore, as novel molecular pathways relevant to breast cancer biology are explored, it is expected that a whole array of targeted agents will be tested in combination or in sequence to standard chemotherapy with the aim to improve outcome of high-risk breast cancer patients.

Lack of prognostic and predictive value of CA IX in radiotherapy of squamous cell carcinoma of the head and neck with known modifiable hypoxia: An evaluation of the DAHANCA 5 study

BACKGROUND AND PURPOSE

CA IX is suggested to be an endogenous marker of hypoxia in tumours like squamous cell carcinomas of the head and neck (HNSCC). The aim of the present study was to investigate whether CA IX served as a prognostic factor for outcome in a large population of HNSCC and if CA IX was able to discriminate the tumours that did benefit from hypoxic modification with nimorazole.

MATERIALS AND METHODS

Paraffin-embedded formalin-fixed pre-treatment tumour tissue was available from 320 of the 414 patients treated in the randomized DAHANCA 5 protocol with primary radiotherapy+/-the hypoxic radiosensitizer nimorazole. CA IX was measured using immunohistochemistry and results were divided into four groups of CA IX expression: <1%, 1-10%, 10-30% and >30% of the tumour area with positive membrane staining. Locoregional control and disease-specific survival were used as endpoints.

RESULTS

Expression of CA IX was not correlated to any of the tumour or patient characteristics investigated. Furthermore, CA IX did not serve as a prognostic marker in the total cohort as well as in the group of 150 patients treated without nimorazole. Finally, no relation was found between the different expression levels of CA IX and the influence of nimorazole when locoregional control or disease-specific survival was used as endpoints.

CONCLUSIONS

This is to date one of the largest studies of CA IX in HNSCC. The data suggest that CA IX have no prognostic or predictive potential in patients with cancer in the head and neck treated with conventional radiotherapy and concomitant nimorazole.

Molecular determinants of immunogenic cell death: surface exposure of calreticulin makes the difference

The treatment of cancer by chemotherapy causes tumour cell death, mostly by apoptosis. This tumour cell death may or may not elicit an immune response. At least in some cases, the efficacy of chemotherapy critically depends on the induction of immunogenic cell death that is a type of cell demise that stimulates the activation of an adaptative anti-tumour immune response, which in turn helps to eradicate residual cancer (stem) cells. Indeed, anthracyclins care more efficient in curing tumours in immunocompetent than in T cell-deficient mice. The molecular mechanism implicated in this anti-tumour T cell activation was recently discovered. Anthracyclins cause immunogenic cell death due to their specific capacity to stimulate the translocation of calreticulin to the cell surface. Calreticulin then acts as an "eat me" signal for dendritic cells, allowing them to phagocytose tumour cells and to prime tumour antigen-specific cytotoxic T cells. Importantly, non-immunogenic chemotherapy can be rendered immunogenic by adsorbing recombinant calreticulin to tumour cells or by enforcing the translocation of endogenous calreticulin to the cell surface by means of PP1/GADD34 inhibitors. This strategy could have major implications for the treatment of human cancer. Indeed, in vivo treatments with anthracyclins can cause the translocation of calreticulin to the surface of circulating tumour cells, in patients with acute myeloid leukaemia (AML). The challenge will be to determine whether the exposure of calreticulin translocation on the tumour cell surface is linked to chemotherapy-induced anti-tumour immune responses and therapeutic efficacy in human cancer.

Imaging the hypoxia surrogate marker CA IX requires expression and catalytic activity for binding fluorescent sulfonamide inhibitors

BACKGROUND AND PURPOSE

Carbonic anhydrase (CA) IX expression is increased in response to hypoxia. Recently, sulfonamide based carbonic anhydrase inhibitors (CAI) showing specificity for CA IX have been designed. Aim was to investigate the CAI binding properties under normoxia, hypoxia and reoxygenation.

MATERIAL AND METHODS

Cells with varying CA IX expression were incubated with fluorescein labeled CAI (1mM) during normoxia, hypoxia (0.2%) and reoxygenation. CA IX expression levels were assessed using Western blotting. CAI binding was determined by immunostaining and flow cytometry.

RESULTS

CAI binding in hypoxic cells was significantly higher compared with normoxic cells and correlated with upregulated CA IX levels. Binding occurred within 15min of hypoxia, but was gradually lost upon reoxygenation. Interestingly, although CA IX levels remained high upon reoxygenation, CAI binding was dramatically reduced and no longer correlated with CA IX expression. Similarly, RCC4 cells, constitutively expressing CA IX, do not bind CAI under normoxic conditions.

CONCLUSIONS

Our results confirm and extend previous results showing that CAI binding occurs only under hypoxia. The inability of CAI to bind CA IX in RCC4 cells and following reoxygenation in other cells demonstrates that formation of the active site not only depends on HIF-1alpha-dependent gene activity, but also on the absence of oxygen per se.

Cancer vaccines: challenges and outlook in the field

Therapeutic vaccination against cancer-associated antigens represents an attractive option for cancer therapy in view of its efficacy, the possibility of long-lasting immunity against the cancer, and safety profile. Nevertheless, it is now recognized that the same vaccination strategies used for prophylactic vaccinations against infectious diseases, cannot necessarily be used for therapeutic cancer vaccination. Cancer patients are usually immunosuppressed and most cancer-associated antigens are 'self-antigens', making it a significant challenge to vaccinate patients against a cancer-associated antigen. Various immunostimulation techniques are under investigation in an effort to bolster patients' immune systems and to overcome immune tolerance to self antigens. Strategies to stimulate antigen presentation, T-cell reactivity and innate immune activity are under investigation. Several clinical trials have been conducted to evaluate therapeutic cancer vaccines in patients, and attractive protocols, including those that combine the stimulation of specific T-cells and chemotherapy, or strategies to block immune regulation, are beginning to show some success. This feature review considers strategies for the development of effective therapeutic cancer vaccines, and highlights select vaccines that have already entered the clinic.

Modulation of CLA, IL-12R, CD40L, and IL-2Rα expression and inhibition of IL-12- and IL-23-induced cytokine secretion by CNTO 1275

Cytokines interleukin (IL)-12 and IL-23 are implicated in the pathogenesis of psoriasis. IL-12 causes differentiation of CD4+ T cells to interferon-gamma (IFN-gamma)-producing T helper 1 (Th1) cells, while IL-23 induces differentiation to IL-17-producing pathogenic Th17 cells. The effects of the monoclonal antibody to IL-12/23 p40 subunit (CNTO 1275) on IL-12 receptor (IL-12R) expression, markers associated with skin homing, activation, and cytokine secretion were investigated in vitro using human peripheral blood mononuclear cells (PBMCs) from healthy donors. PBMCs were activated in the presence or absence of recombinant human (rh) IL-12 or rhIL-23, with or without CNTO 1275. CNTO 1275 inhibited upregulation of CLA, IL-12R, IL-2Ralpha and CD40L expression and also inhibited IL-12- and IL-23-induced IFN-gamma, IL-17A, tumor necrosis factor (TNF)-alpha, IL-2, and IL-10 secretion. Thus, the therapeutic effect of CNTO 1275 may be attributed to the IL-12/23 neutralization, resulting in decreased expression of skin homing and activation markers, and IL-12- and IL-23-induced cytokine secretion.

Normal values for KL-6 in cord venous plasma of neonates

BACKGROUND

KL-6 in umbilical cord blood, including from premature infants, and perinatal factors that may affect these values have not yet been adequately discussed. The authors investigated factors affecting cord venous plasma levels of KL-6 in neonates, and to establish a normal range of values for KL-6 in neonatal cord blood.

METHODS

Cord plasma levels of KL-6 were measured in 75 neonates, and statistical analysis of factors affecting these levels was performed. A normal range for cord plasma KL-6 levels was calculated by statistical analysis methods based on guidelines by the National Committee for Clinical Laboratory Standards.

RESULTS

Data from a total of 75 neonates was analyzed. Gestational age ranged from 25 to 40 weeks (median, 33.4 weeks), and birthweight ranged from 776 to 3760 g (median, 1944 g). There was no statistically significant correlation between cord plasma KL-6 levels with gender, gestational age, birthweight, method of delivery, Apgar score 1 min, and postnatal respiratory distress. The normal range of values for cord plasma KL-6 was 44.3-148.2 U/mL (median, 73.0 U/mL).

CONCLUSION

The cord plasma levels of KL-6 were about half the normal values reported in children and healthy adults and were not affected by various perinatal factors. The authors' findings suggest that plasma KL-6 levels rise when respiratory function is established after birth and tend to further increase with age.

Pharmacodiagnostics and Targeted Therapies—A Rational Approach for Individualizing Medical Anticancer Therapy in Breast Cancer

The selection of therapy for a particular breast cancer patient is traditionally based on average results from randomized clinical trials. Rational pharmacotherapy is in essence about selecting the right drug(s) for the right patient, and in order to guide this selection process pharmacodiagnostic tests are indispensable. A number of tests have been developed or are under development for targeted therapies, such as antiestrogens, human epidermal growth factor receptor 2 inhibitors, and topoisomerase inhibitors. Based on a biopsy from the tumor, the tests are able to identify patients with a high probability to benefit from these therapies. The detection of the predictive biomarkers is based on different technologies, such as immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization. Pharmacodiagnostic tests will play an important role in the further development of targeted therapies and may be seen as a prerequisite for the introduction of individualized medicine in oncology.

TOP2A and HER2 gene amplification as predictors of response to anthracycline treatment in breast cancer

The purpose of this study was to evaluate amplification of topoisomerase IIalpha (TOP2A) and HER2 genes as predictors of response to chemotherapy in advanced breast cancer. Gene copy number of TOP2A and HER2 were analysed with chromogenic in situ hybridization (CISH) on paraffin-embedded tissue sections from the primary tumour of 85 patients treated with anthracycline containing chemotherapy. TOP2A gene amplification was present in 14 (16%) and HER2 gene amplification in 38 (45%) of the primary tumours. Two of the 14 cases with TOP2A amplification were amplified without concurrent HER2 amplification. Neither TOP2A nor HER2 gene amplification were significantly associated with response to chemotherapy (p = 0.35 and p = 0.49, respectively).

Combined Treatment with Temozolomide and Methoxyamine: Blocking Apurininc/Pyrimidinic Site Repair Coupled with Targeting Topoisomerase IIα

PURPOSE

Methoxyamine has been shown to potentiate the cytotoxic effect of temozolomide both in vitro and in human tumor xenograft models. We postulate that the enhanced cytotoxicity is mediated by methoxyamine-bound apurininc/pyrimidinic (MX-AP) site, a key lesion formed by the combination of temozolomide and methoxyamine. When located within topoisomerase IIalpha (topo II) cleavage sites in DNA, MX-AP sites act as dual lethal targets, not only functionally disrupting the base excision repair (BER) pathway but also potentially poisoning topo II.

EXPERIMENTAL DESIGN

Using oligonucleotide substrates, in which a position-specific MX-AP site is located within topo II cleavage sites, we examined the effect of MX-AP site on both AP endonuclease- and topo II-mediated DNA cleavage in vitro.

RESULTS

MX-AP sites were refractory to the catalytic activity of AP endonuclease, indicating their ability to block BER. However, they were cleaved by either purified topo II or nuclear extracts from tumor cells expressing high levels of topo II, suggesting that MX-AP sites stimulate topo II-mediated DNA cleavages. In cells, treatment with temozolomide and methoxyamine increased the expression of topo II and enriched the formation of gammaH2AX foci, which were colocalized with up-regulated topo II, confirming that DNA double-strand breaks marked by gammaH2AX foci are associated with topo II in cells.

CONCLUSIONS

Our findings identify a molecular mechanism of cell death whereby MX-AP sites that cumulated in cells due to resistance to BER potentially convert topo II into biotoxins, resulting in enzyme-mediated DNA scission and cell death.

Re-occurrence of the CD20 molecule expression subsequent to CD20-negative relapse in diffuse large B-cell lymphoma

We report the first case of diffuse large B-cell lymphoma (DLBCL) of the stomach displaying CD20-negative relapse after rituximab-containing treatment and the re-appearance of CD20 expression at the second failure. The loss of CD20 expression in B-cell lymphomas relapsing after rituximab is a well-known phenomenon, but its actual impact in DLBCL is difficult to estimate. This paradigmatic case suggests that CD20-expression reappearance after purging of CD20-positive clones with rituximab might be an underestimated occurrence in B-cell lymphomas. Accordingly, every relapse, whenever possible, should be histologically assessed with diagnostic and immunophenotyping purposes.

Heterogeneous CD52 Expression among Hematologic Neoplasms: Implications for the Use of Alemtuzumab (CAMPATH-1H)

PURPOSE

CD52 is a GPI-linked glycoprotein expressed by B cells, T cells, monocytes, and macrophages. The humanized monoclonal antibody alemtuzumab (CAMPATH-1H) is specific for CD52 and is Food and Drug Administration - approved for the treatment of relapsed or refractory chronic lymphocytic leukemia (CLL). The utility of CAMPATH in the treatment of other hematologic neoplasms has been explored; however, a comprehensive survey of CD52 expression among a broad spectrum of WHO-defined tumor types has not been completed.

EXPERIMENTAL DESIGN

We evaluated 294 hematologic neoplasms for the presence of CD52 using standard immunohistochemical techniques on paraffin-embedded biopsy specimens fixed with formalin, B-Plus, Zenker's acetic acid, or B5-formalin.

RESULTS

The vast majority of low-grade B cell lymphoproliferative disorders (CLL/small lymphocytic leukemia, follicular lymphoma, lymphoplasmacytic lymphoma, hairy cell leukemia, and mucosa-associated lymphoid tissue lymphomas) express CD52. In addition, we found that the majority of precursor B cell acute lymphoblastic leukemia/lymphomas express this antigen. In contrast, there is surprising heterogeneity in CD52 expression among more aggressive B cell lymphomas, with 25% of cases of diffuse large B cell lymphoma and Burkitt lymphoma demonstrating no detectable CD52. In addition, the majority of neoplasms of the T cell lineage are negative for the antigen, including most cases of precursor T cell acute lymphoblastic leukemia/lymphoma, anaplastic large cell lymphoma, and peripheral T cell lymphoma, not otherwise specified. Finally, the vast majority of cases of acute myeloid leukemia, Hodgkin lymphoma, and multiple myeloma are negative for CD52 expression.

CONCLUSION

In contrast with CLL, the variable expression of CD52 among other hematologic malignancies suggests that target validation on a case-by-case basis will likely be necessary to guide the rational analysis of CAMPATH therapy.

A Structure-Based 3D-QSAR Study of Anthrapyrazole Analogues of the Anticancer Agents Losoxantrone and Piroxantrone

A series of 13 anthrapyrazole compounds that are analogues of piroxantrone and losoxantrone were synthesized, and their cell growth inhibitory effects, DNA binding, topoisomerase IIalpha mediated (EC 5.99.1.3) cleavage of DNA, and inhibition of DNA topoisomerase IIalpha decatenation catalytic activities were determined. Cell growth inhibitory activity was well-correlated with DNA binding, suggesting that these compounds may act by targeting DNA. However, cell growth inhibition was not well-correlated with the inhibition of topoisomerase IIalpha catalytic activity, suggesting that these anthrapyrazoles did not act solely by inhibiting the catalytic activity of topoisomerase II. Most of the analogues were able to induce DNA cleavage, and thus, it was concluded that they acted, at least in part, as topoisomerase II poisons. Structure-based three-dimensional quantitative structure-activity analyses (3D-QSAR) were carried out on the aligned structures of the anthrapyrazoles docked into DNA using comparative molecular field analysis (CoMFA) and comparative molecular similarity index (CoMSIA) analyses in order to determine the structural features responsible for their activity. Both CoMFA and CoMSIA yielded statistically significant models upon partial least-squares analyses. The 3D-QSAR analyses showed that hydrogen-bond donor interactions and electrostatic interactions with the protonated amino side chains of the anthrapyrazoles led to high cell growth inhibitory activity.

Carbonic anhydrase inhibitors: Transepithelial transport of thioureido sulfonamide inhibitors of the cancer-associated isozyme IX is dependent on efflux transporters

Sulfonamides and their derivatives inhibit the catalytic activity of carbonic anhydrases (CA, EC 4.2.1.1). Isozyme IX (CA IX) is a transmembrane isoform with the active site oriented toward the extracellular space. CA IX was recently shown to be a drug target, and it is highly overexpressed in hypoxic tumors with limited distribution in normal tissues. The present report deals with the drug design, synthesis, and biological investigation of a group of thioureido sulfonamides, which have been obtained by reaction of isothiocyanate-substituted aromatic sulfonamides with amines. These compounds have potent inhibitory properties against CA IX with K(I) values in the range of 10-37 nM and P(app)values > 0.34 x 10(-6) cm/s for the absorptive transepithelial transport in Caco-2 cells. In Caco-2 cells, one of these compounds (A6) was shown to be a substrate for efflux transporters such as P-glycoprotein (P-gp). P-gp activity is not likely to be rate-limiting for intestinal absorption, but might be useful when targeting hypoxic tumors expressing both P-gp and CA IX.

Principles and use of anti-CTLA4 antibody in human cancer immunotherapy

Cytotoxic T lymphocyte antigen-4 has become recognized as one of the key negative regulators of adaptive immune responses, having a central role in the maintenance of peripheral tolerance and in shaping the repertoire of emergent T cell responses. Concurrent recognition of the potential importance of inhibitory immune regulators in limiting antitumor responses, either as a result of chronic antigenic stimulation or the self-nature of many tumor-selective target antigens, has led to the development of cytotoxic T lymphocyte antigen-4-blocking antibodies as therapeutic anticancer agents. Following extensive preclinical modeling, these agents have entered clinical trials, where they are showing encouraging activity in heavily pretreated patients with advanced-stage disease, particularly with melanoma or renal carcinoma. Finding ways to dissociate antitumor activity from adverse immune events should enable actualization of their therapeutic potential in the coming years.

Dipeptide-based highly potent doxorubicin antibody conjugates

Highly potent and novel derivatives of doxorubicin were linked to monoclonal antibodies (mAbs) for site-specific drug delivery. Drug linker 5 consisted of a dipeptide linker attached directly to the daunosamine nitrogen of the n-butyldiacetate doxorubicin derivative 2a. Upon hydrolysis of the peptide linker and acetate groups, the free daunosamine nitrogen is able to form the highly potent 2-pyrrolinodoxorubicin (3a). The second approach involved the use of an oxazolidine carbamate (13) to mask an activating aldehyde group until proteolytic hydrolysis releases 3a. Both drug linkers were shown to be substrates for the lysosomal enzyme cathepsin B. Each molecule was conjugated to the mAbs c1F6 (anti-CD70) and cAC10 (anti-CD30) to give potent drug conjugates against renal cell carcinoma and anaplastic large cell lymphoma cell lines, respectively. The activities were immunologically selective, since antigen negative cell lines were much less sensitive to treatment with the drug conjugates. The approaches described here for attaching highly potent doxorubicin derivatives to mAbs are novel and allow for control of drug stability while covalently bound to the delivery agent.

Synthesis and biological evaluation of novel pyrrolo[2,1-c][1,4]benzodiazepine prodrugs for use in antibody-directed enzyme prodrug therapy

The design, synthesis and evaluation of four novel pyrrolo[2,1-c][1,4]benzodiazepine (PBD) prodrugs (1a,b and 2a,b; ) for potential use in carboxypeptidase G2 (CPG2)-based antibody-directed enzyme prodrug therapy (ADEPT) is reported. Although all four prodrugs were shown to be less cytotoxic than the released parent PBDs 3 and 4, the urea prodrugs 1b and 2b were found to be too unstable for use in ADEPT, whereas carbamates 1a and 2a are both stable in an aqueous environment and are good substrates for CPG2.

Carbonic anhydrase inhibitors: Inhibition of the human isozymes I, II, VA, and IX with a library of substituted difluoromethanesulfonamides

An inhibition study of the human cytosolic isozymes I, and II, the mitochondrial isoform VA, and the tumor-associated, transmembrane isozyme IX of carbonic anhydrase (CA, EC 4.2.1.1) with a library of aromatic/heteroaromatic/polycyclic difluoromethanesulfonamides is reported. Most of the inhibitors were derivatives of benzenedifluoromethanesulfonamide incorporating substituted-phenyl moieties, or were methylsulfonamide and difluoromethyl-sulfonamide derivatives of the sulfamates COUMATE and EMATE, respectively. Except for the methylsulfonamide-COUMATE derivative which behaved as a potent CA II inhibitor (K(I) of 32nM), these sulfonamides were moderate inhibitors of all isozymes, with inhibition constants in the range of 96-5200nM against hCA I, of 80-670nM against hCA II, and of 195-9280nM against hCA IX, respectively. Remarkably, some derivatives, such as 3-bromophenyl-difluoromethanesulfonamide, showed a trend to selectively inhibit the mitochondrial isoform CA VA, showing selectivity ratios for inhibiting CA VA over CA II of 3.53; over CA I of 6.84 and over CA IX of 9.34, respectively, although it is a moderate inhibitor (K(I) of 160nM). Some of these derivatives may be considered as leads for the design of isozyme selective CA inhibitors targeting the mitochondrial isozyme CA VA, with potential use as anti-obesity agents.

Carbonic anhydrase inhibitors: Inhibition of cytosolic/tumor-associated carbonic anhydrase isozymes I, II, and IX with benzo[b]thiophene 1,1-dioxide sulfonamides

A series of selected benzo[b]thiophene-5- and 6-sulfonamide derivatives previously reported to show cytotoxic activity and some others newly synthesized has been tested for the interactions with several CA isozymes, some of which are known to be involved in tumorigenesis (hCA IX), whereas others are ubiquitously found in many normal tissues (the cytosolic isoforms hCA I and II). The unsubstituted sulfonamides inhibited hCA I with inhibition constants in the range of 63-138 nM, hCA II with inhibition constants in the range of 6.3-8.8 nM, and hCA IX with inhibition constants in the range of 2.8-15 nM, being thus more active than clinically used inhibitors such as acetazolamide, methazolamide, ethoxzolamide, dichlorophenamide or indisulam (E 7070). Some of these derivatives also showed some selectivity for the inhibition of the tumor-associated (hCA IX) over the cytosolic isozyme hCA II. Although these derivatives may act on many targets other than the CAs (such as the NADH oxidase) or may induce apoptosis by accumulation of reactive oxygen species, it is quite important to try to decipher as many as possible of the potential mechanisms that lead to derivatives with potent antitumor activity in order to develop novel therapeutic strategies for the management of cancer.

Carbonic anhydrase inhibitors: Inhibition of the tumor-associated isozymes IX and XII with a library of aromatic and heteroaromatic sulfonamides

The inhibition of the two transmembrane, tumor-associated isozymes of carbonic anhydrase (CA, EC 4.2.1.1) of human origin, hCA IX and XII, with a library of aromatic and heteroaromatic sulfonamides has been investigated. Most of them were sulfanilamide, homosulfanilamide, and 4-aminoethyl-benzenesulfonamide derivatives, to which tails that should induce diverse physico-chemical properties have been attached at the amino moiety, whereas several of these compounds were derived from metanilamide, benzene-1,3-disulfonamide or the 1,3,4-thiadiazole/thiadiazoline-2-sulfonamides. The tails were of the alkyl/aryl-carboxamido/sulfonamido-, ureido or thioureido type. Against hCA IX the investigated compounds showed inhibition constants in the range of 3-294 nM, whereas against hCA XII in the range of 1.9-348 nM, respectively. The best hCA IX inhibitors were ureas/thioureas incorporating 4-aminoethyl-benzenesulfonamide and metanilamide moieties. The best hCA XII inhibitors were 1,3,4-thiadiazole/thiadiazoline-2-sulfonamides incorporating 5-acylamido or 5-arylsulfonylamido moieties. These compounds also inhibited appreciably the cytosolic isozymes hCA I and II, but some selectivity for the transmembrane, tumor-associated isozymes was observed for some of them, which is an encouraging result for the design of novel therapies targeting hypoxic tumors, in which these carbonic anhydrases are highly overexpressed.

Immune responses in advanced colorectal cancer following repeated intradermal vaccination with the anti-CEA murine monoclonal antibody, PR1A3: results of a phase I study

BACKGROUND AND AIMS

The aim was to determine the toxicity, clinical and immune responses to the murine monoclonal anti-carcinoembryonic antigen (CEA) antibody, PR1A3, in patients with advanced colorectal cancer.

MATERIALS AND METHODS

Fifteen patients with advanced colorectal cancer received either 0.5-, 1.0- or 5.0-mg doses of PR1A3 mixed with 10% w/v Alum adjuvant (Superfos Biosector, Denmark) intradermally at 4-week intervals for 3 months. Patient serum was assessed for anti-idiotypic (Ab2), anti-anti-idiotypic (Ab3) and human anti-mouse antibody (HAMA) reactivity. Peripheral blood mononuclear cell (PBMC) proliferation with phytohaemagglutinin (PHA), CEA and PR1A3, stimulated IL-2, IL-4 and IFN-gamma levels and PR1A3-stimulated IL-2 receptor expression during immunotherapy were determined. Comparisons were made with 16 age-matched controls without malignant disease.

RESULTS

Hyperimmune sera from 12 of the 15 patients showed Ab2 reactivity with no detectable Ab3 responses. Strong HAMA reactivity was recorded in 7 of the 15 cases with no adverse clinical effect. Delayed-type hypersensitivity (DTH) responses developed in 12 of the 15 patients. Pre-treatment PBMC proliferation with PHA was subnormal in each patient compared with controls, becoming normal (or supranormal) in all patients during immunisation (P<0.001). PBMC proliferation with CEA and PR1A3 increased during immunotherapy (P<0.001) along with stimulated production of IL-2, IFN-gamma and IL-2 receptor expression. Progressive disease was observed in 14 of the 15 patients with minimal toxicity.

CONCLUSION

PR1A3 generated limited idiotypic responses but robust DTH reactivity in most patients. In vitro PBMC proliferation with mitogens and recall antigens is greatly increased during the course of immunisation, with a shift in stimulated cytokine profile.