Cell Adhesion Molecules and Their Roles and Regulation in the Immune and Tumor Microenvironment

The immune system and cancer have a complex relationship with the immune system playing a dual role in tumor development. The effector cells of the immune system can recognize and kill malignant cells while immune system-mediated inflammation can also promote tumor growth and regulatory cells suppress the anti-tumor responses. In the center of all anti-tumor responses is the ability of the immune cells to migrate to the tumor site and to interact with each other and with the malignant cells. Cell adhesion molecules including receptors of the immunoglobulin superfamily and integrins are of crucial importance in mediating these processes. Particularly integrins play a vital role in regulating all aspects of immune cell function including immune cell trafficking into tissues, effector cell activation and proliferation and the formation of the immunological synapse between immune cells or between immune cell and the target cell both during homeostasis and during inflammation and cancer. In this review we discuss the molecular mechanisms regulating integrin function and the role of integrins and other cell adhesion molecules in immune responses and in the tumor microenvironment. We also describe how malignant cells can utilize cell adhesion molecules to promote tumor growth and metastases and how these molecules could be targeted in cancer immunotherapy.Peer reviewe

Novel systemic treatment options for advanced solid tumors with or without central nervous system metastases or malignant glioma

Chemotherapy is a very frequently used therapy in patients with advanced tumors with or without central nervous system (CNS) metastases or primary brain tumors. Despite the significant progress in drug development, the survival of patients is limited with an unmet need for more effective chemotherapeutics that have an acceptable safety profile. This thesis presents I/II clinical phase studies with an aim to investigate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and the preliminary anti-tumor activity of novel anti-cancer drugs or new combinations of drugs already in use. During the research we were able to recommend dosing schedules and dose-levels of the (combination of) drug(s) for further clinical studies and confirmed drug-drug interactions or food-effects. The second part of this thesis presents pharmaceutical/nanomedicine strategies and laboratory assays in the treatment, diagnosis and drug-monitoring of central nervous system (CNS) tumors. We represent the review of the literature that discusses new drug strategies of targeting blood-brain barrier (BBB) by active chemo- and immunotherapies. Due to the presence of the blood-brain barrier (BBB) only few systemic drugs can be used to treat brain tumors. As treatment of systemically metastasized cancer patients becomes more effective and prolongs patient’s survival, CNS metastases are more frequently observed. Recently, using nanotechnology active chemotherapeutics can be safely transported across the barriers (BBB and blood-cerebrospinal fluid barrier (BCSFB)) and target brain and CSF, respectively. Further studies on improving the brain-penetration of potentially effective drugs for brain tumors is warranted. In the line with this we describe two clinical studies with a novel strategy consisting of administration of glutathione liposomal PEGylated doxorubicin (2B3-101) as a treatment of patients with solid tumors and brain metastases or recurrent malignant glioma and leptomeningeal metastases from breast cancer. Doxorubicin is a well- known, frequently used chemotherapeutic agent in various tumor types, such as breast cancer and lung cancer. Glioblastoma cell lines showed to be sensitive to doxorubicin, however, without the carrier, doxorubicin cannot pass the BBB. The first study with 2B3-101 demonstrated that treatment of patients with solid tumors and brain metastases or malignant gliomas with 2B3-101 showed a dose-dependent PK profile and is safe and relatively well tolerated with both as single agent and with trastuzumab co-administration. Intracranial and extracranial preliminary anti-tumor activity was observed in patients with (HER2+) breast cancer with brain metastases and malignant glioma. In the second study using 2B3-101 in patients with leptomeningeal metastases (LM) from breast cancer, doxorubicin concentrations in the CSF were within the reported IC50, a measure of effectiveness in-vitro in two out of three patients. One of the three treated patients with LM showed stable disease for 10 cycles and progression free survival for more than six months. Further we demonstrate the clinical application of the circulating tumor cell assay (CTC) for EPCAM-positive cells (an epithelial tumor cell marker) to be more sensitive in diagnosing leptomeningeal metastases in CSF (100%), than the standard CSF cytology method (71%) in patients with clinically suspected LM or with already diagnosed LM, while both methods showed a very high specificity (100%)

Novel systemic treatment options for advanced solid tumors with or without central nervous system metastases or malignant glioma

Chemotherapy is a very frequently used therapy in patients with advanced tumors with or without central nervous system (CNS) metastases or primary brain tumors. Despite the significant progress in drug development, the survival of patients is limited with an unmet need for more effective chemotherapeutics that have an acceptable safety profile. This thesis presents I/II clinical phase studies with an aim to investigate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and the preliminary anti-tumor activity of novel anti-cancer drugs or new combinations of drugs already in use. During the research we were able to recommend dosing schedules and dose-levels of the (combination of) drug(s) for further clinical studies and confirmed drug-drug interactions or food-effects. The second part of this thesis presents pharmaceutical/nanomedicine strategies and laboratory assays in the treatment, diagnosis and drug-monitoring of central nervous system (CNS) tumors. We represent the review of the literature that discusses new drug strategies of targeting blood-brain barrier (BBB) by active chemo- and immunotherapies. Due to the presence of the blood-brain barrier (BBB) only few systemic drugs can be used to treat brain tumors. As treatment of systemically metastasized cancer patients becomes more effective and prolongs patient’s survival, CNS metastases are more frequently observed. Recently, using nanotechnology active chemotherapeutics can be safely transported across the barriers (BBB and blood-cerebrospinal fluid barrier (BCSFB)) and target brain and CSF, respectively. Further studies on improving the brain-penetration of potentially effective drugs for brain tumors is warranted. In the line with this we describe two clinical studies with a novel strategy consisting of administration of glutathione liposomal PEGylated doxorubicin (2B3-101) as a treatment of patients with solid tumors and brain metastases or recurrent malignant glioma and leptomeningeal metastases from breast cancer. Doxorubicin is a well- known, frequently used chemotherapeutic agent in various tumor types, such as breast cancer and lung cancer. Glioblastoma cell lines showed to be sensitive to doxorubicin, however, without the carrier, doxorubicin cannot pass the BBB. The first study with 2B3-101 demonstrated that treatment of patients with solid tumors and brain metastases or malignant gliomas with 2B3-101 showed a dose-dependent PK profile and is safe and relatively well tolerated with both as single agent and with trastuzumab co-administration. Intracranial and extracranial preliminary anti-tumor activity was observed in patients with (HER2+) breast cancer with brain metastases and malignant glioma. In the second study using 2B3-101 in patients with leptomeningeal metastases (LM) from breast cancer, doxorubicin concentrations in the CSF were within the reported IC50, a measure of effectiveness in-vitro in two out of three patients. One of the three treated patients with LM showed stable disease for 10 cycles and progression free survival for more than six months. Further we demonstrate the clinical application of the circulating tumor cell assay (CTC) for EPCAM-positive cells (an epithelial tumor cell marker) to be more sensitive in diagnosing leptomeningeal metastases in CSF (100%), than the standard CSF cytology method (71%) in patients with clinically suspected LM or with already diagnosed LM, while both methods showed a very high specificity (100%)

Strategies to target drugs to gliomas and CNS metastases of solid tumors

The treatment for central nervous system metastases of solid tumors and gliomas is limited as the blood–brain barrier (BBB) is an obstacle to systemic therapy. Here, we review the physiochemical properties of the BBB and both current and new drug strategies to penetrate brain tumors. We focus on targeting receptor- or carrier-mediated transport mechanisms over the BBB used by drug conjugates, nanoparticles, polymer-based nanocarriers, siRNA, and antibodies

EpCAM-based flow cytometry in cerebrospinal fluid greatly improves diagnostic accuracy of leptomeningeal metastases from epithelial tumors

BACKGROUND: Moderate diagnostic accuracy of MRI and initial cerebrospinal fluid (CSF) cytology analysis results in at least 10%-15% false negative diagnoses of leptomeningeal metastases (LM) of solid tumors, thus postponing start of therapy. The aim of this prospective clinical study was to determine the diagnostic value of epithelial cell adhesion molecule (EpCAM)-based flow cytometry versus cytology in CSF for the diagnosis of LM in patients with epithelial tumors. METHODS: Patients with a clinical suspicion of LM but a negative or inconclusive MRI in whom a diagnostic lumbar puncture has to be performed were included. At least 5 mL of CSF for cytology, 5 mL for flow cytometry, 2 mL for cell count and biochemistry, and 8 mL whole blood samples for circulating tumor cells measurements and biochemistry were drawn. Tumor cells in CSF and whole blood were detected by multiparameter flow cytometry using EpCAM antibody. RESULTS: In total 29 eligible patients were enrolled in the study. Thirteen patients were ultimately diagnosed with LM. The flow cytometry assay showed 100% sensitivity and 100% specificity for diagnosing LM, while sensitivity of CSF cytology was only 61.5%. Cell count or biochemical parameters in CSF were abnormal in 100% of patients with LM. CONCLUSIONS: Our results suggest that the EpCAM-based flow cytometry assay is superior to CSF cytology for the diagnosis of LM in patients with an epithelial tumor, a clinical suspicion of LM, and a nonconclusive MRI. Confirmation of these data is needed in a larger dataset to recommend dual CSF diagnostics for LM. CLINICALTRIALSGOV IDENTIFIER: NCT01713699

Phase i study of lonafarnib (SCH66336) in combination with trastuzumab plus paclitaxel in Her2/neu overexpressing breast cancer: EORTC study 16023

Purpose: This phase I study was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety profile, recommended dose for phase II studies, the pharmacokinetics, and antitumor activity of the combination of lonafarnib (farnesyl transferase inhibitor), trastuzumab, and paclitaxel in Her2-positive advanced breast cancer. Methods: Twenty-three patients with Her2-overexpressing breast cancer received in the first cycle paclitaxel and trastuzumab and from cycle 2 onwards lonafarnib which was added to the combination. Dose-limiting toxicity (DLT) was determined during the second cycle. Results: The MTD and the recommended dose for phase II trials are lonafarnib: 250 mg/day [125 mg/bi-daily (BID)] continuously, paclitaxel: 175 mg/mA 3-h infusion every 3 weeks, and trastuzumab: 4 mg/kg loading dose and 2 mg/kg/week thereafter. The most frequently observed adverse events starting from cycle 1 onwards were alopecia, myalgia, sensory neuropathy, fatigue, arthralgia, leukocytopenia, and neutropenia. From cycle 2 onwards, additional adverse events appeared, such as diarrhea, nausea, dyspepsia, vomiting, and allergy. The mean systemic exposures of both lonafarnib and paclitaxel through all dose levels were higher in the regimen with all three study medications but with no statistically significant difference. Preliminary antitumor activity (CR + PR) was observed in 58 % of all patients. Conclusion: Lonafarnib can be safely combined and tolerated with full doses of paclitaxel and trastuzumab in Her2-positive advanced breast cancer patients. Promising preliminary antitumor activity warrants further evaluation of lonafarnib in combination with paclitaxel and trastuzumab in Her2-positive breast cancer. © 2012 Springer-Verlag Berlin Heidelberg.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Erratum: Phase i study of lonafarnib (SCH66336) in combination with trastuzumab plus paclitaxel in Her2/neu overexpressing breast cancer: EORTC study 16023 (Cancer Chemother Pharmacol (2013) 71 (53-62))

SCOPUS: er.jinfo:eu-repo/semantics/publishe

A dose escalating phase i study of GLPG0187, a broad spectrum integrin receptor antagonist, in adult patients with progressive high-grade glioma and other advanced solid malignancies

Background Integrin signaling is an attractive target for anti-cancer treatment. GLPG0187 is a broad spectrum integrin receptor antagonist (IRA). GLPG0187 inhibited tumor growth and metastasis in mouse models. Methods We aimed to determine the Recommended Phase II Dose (RP2D) and to assess safety and tolerability of continuous i.v. infusion in patients with advanced malignant solid tumors. Anticipated dose levels were 20, 40, 80, 160, 320, and 400 mg/day in a modified 3 + 3 design. Plasma concentrations of GLPG0187 were assessed to characterize the pharmacokinetics (PK). C-terminal telopeptide of type I collagen (CTX) was used as pharmacodynamics marker. Results Twenty patients received GLPG0187. No dose limiting toxicities (DLTs) were observed. The highest possible and tested dose was 400 mg/day. Fatigue was the most frequently reported side effect (25 %). Recurrent Port-A-Cath-related infections and skin toxicity suggest cutaneous integrin inhibition. No dose-dependent toxicity could be established. PK analysis showed a short average distribution (0.16 h) and elimination (3.8 h) half-life. Continuous infusion resulted in dose proportional PK profiles. We observed decreases in serum CTX levels independent of the dose given, suggesting target engagement at the lowest dose level tested. Single agent treatment did not result in tumor responses. Conclusions GLPG0187 was well tolerated with a dose-proportional PK profile upon continuous infusion. No formal maximal tolerated dose could be established. GLPG0187 showed signs of target engagement with a favourable toxicity profile. However, continuous infusion of GLPG0187 failed to show signs of monotherapy efficacy