Developing FGFR4 inhibitors as potential anti-cancer agents via in silico design, supported by in vitro and cell-based testing

Fibroblast growth factor receptor-4 (FGFR4) is a tyrosine kinase with a range of important physiological functions. However, it is also frequently mutated in various cancers and is now generating significant interest as a potential therapeutic target. Unfortunately, biochemical characterization of its role in disease, and further evaluation as a drug target is hampered by lack of a specific inhibitor. We aimed to discover new inhibitors for FGFR4 ab initio using a strategy combining in silico, in vitro and cell-based assays. We used the homologous FGFR1 to calculate docking scores of a chemically-diverse library of approximately 2000 potential kinase inhibitors. Nineteen potential inhibitors and ten randomly- selected negative controls were taken forward for in vitro FGFR4 kinase assays. All compounds with good docking scores significantly inhibited FGFR4 kinase activity, some with sub-micromolar (most potent being V4-015 with an IC(50) of 0.04 μM). Four of these compounds also demonstrated substantial activity in cellular assays using the FGFR4- overexpressing breast carcinoma cell line, MDA-MB453. Through immunoblot assays, these compounds were shown to block the phosphorylation of the FGFR4 adaptor protein, FGFR substrate protein-2α (FRS2α). The most potent compound to date, V4-015, suppressed proliferation of MDA-MB453 cells at sub-micromolar concentrations, activated the pro-apoptotic caspases 3/7 and inhibited cellular migration. While achieving complete selectivity of this compound for FGFR4 will require further lead optimization, this study has successfully identified new chemical scaffolds with unprecedented FGFR4 inhibition capacities that will support mechanism of action studies and future anti-cancer drug design.

[Female patients with fibromyalgia syndrome in somatic and psychosomatic rehabilitation center - an exploratory study on access routes and differences in patient characteristics]

STUDY OBJECTIVE

Fibromyalgia syndrome (FMS) is characterized by e. g. chronic, multilocular pain, and mental health problems. In Germany, patients with FMS are treated in somatic and psychosomatic rehabilitation centers - specialized for rheumatic diseases (somatic) or psychosomatic diseases. The aim of this study is to identify the status quo of FMS patients' access routes to the rehabilitation system, and to identify their predictors for being assigned to one or the other indication group.

METHOD

Our cohort consists of 197 FMS patients from 3 psychosomatic (M=49.9 years) and 223 FMS patients (M=50.2 years) from 3 somatic rehabilitation centers. At the beginning of rehabilitation, patients filled out a questionnaire packet to identify their access routes to the rehabilitation centers and to record patients' disease-related, psychosocial and socio-demographic characteristics. To analyze the results we used descriptive calculations, calculated bivariate correlations, and conducted binary logistic regression analysis for the prediction of group membership.

RESULTS

The access routes of FMS patients to a somatic or a psychosomatic rehabilitation center were often similar. Some items revealed significant group differences, i. e., a higher primary -rejection rate, longer waiting period between application for rehabilitation and its approval, and between the application itself and initiation of psychosomatic rehabilitation in comparison to somatic FMS patients. Prior experience of out-patient psychotherapy, and expectations ("psychological support") for the rehabilitation were predictive patient characteristics for the assignment into a psychosomatic rehabilitation center. Marriage, motivation, and expectations ("physical improvement" and "interaction with other patients") for the rehabilitation were predictive patient characteristics for the assignment in a somatic rehabilitation center. The predictors clarified 32% of the variance of group membership.

CONCLUSION

Our results provide initial evidence of how FMS patients access the German rehabilitation system and which of their characteristics are responsible for being assigned to a particular rehabilitation setting.

[Evaluation of a Vocationally Oriented Concept within Inpatient Oncological Rehabilitation]

AIM OF THE STUDY

We evaluated an occupation-related rehabilitation program, which has been designed to enhance the return to work of cancer patients. As return to work plays an important role to get back to normalcy after suffering from cancer, there is a substantial need for support and evaluated programs.

METHODS

The study had a quasi-experimental design with an intervention group (IG) and a comparison group (CG). We defined performance-related outcomes (e. g. return to work, self-assessed working capacity), asked patients if they needed further vocational advice and how helpful they estimated the rehabilitation treatment. 1 year after the end of rehabilitation 309 employed patients had completed the study (65%). We addressed our research questions using non-parametric tests, t-tests, analyses of variance and logistic regressions.

RESULTS

Of the 309 patients 58% started rehabilitation not later than 14 days after the end of acute treatment while the other 42% had finished their treatments at least some weeks or even months ago. Patients of the IG evaluated the work-related rehabilitation offers significantly better and needed less additional vocational advice after the end of rehabilitation (n. s.). Regarding the patients, who started rehabilitation not later than 14 days after the end of acute treatment (beginning of rehabilitation n=269, 12 months after rehabilitation n=174), the IG achieved a slightly higher return-to-work-rate 12 months after the end of rehabilitation (81% IG, 76% CG, n. s.). Above that the IG estimated their subjective working capacity significantly more often as fully re-established (IG 46%; CG 29%, p=0,030).

CONCLUSIONS

A high percentage of the patients return to work (78%). These results show the success of oncological rehabilitation in helping patients to return to work. In addition, the occupation-related rehabilitation program enhances subjective variables as the satisfaction of the patients regarding the information and the improvement of the patients' working-capacity.

Marginal zone lymphomas with monocytoid morphology express T-bet and are associated with a low number of T cells in extranodal locations

The presence of tumor cells with monocytoid morphology in marginal zone lymphoma (MZL) has been described previously. Reactive monocytoid B cells bear a distinct immunophenotype and typically express T-bet, which clearly distinguishes them from nodal marginal zone B cells. The latter are positive for CD27 and negative for T-bet. We analyzed 74 MZLs for the expression of T-bet and correlated these results with the presence of monocytoid morphology. Expression of T-bet correlated with the presence of monocytoid morphology in MZLs. In analogy to reactive monocytoid B lymphocytes, we also found a significantly lower relative amount of intratumoral T lymphocytes in extranodal MZL with monocytoid morphology.

Anti-angiogenic effects of the tubulysin precursor pretubulysin and of simplified pretubulysin derivatives

BACKGROUND AND PURPOSE

The use of tubulin-binding compounds, which act in part by inhibiting tumour angiogenesis, has become an integral strategy of tumour therapy. Recently, tubulysins were identified as a novel class of natural compounds of myxobacterial origin, which inhibit tubulin polymerization. As these compounds are structurally highly complex, the search for simplified precursors [e.g. pretubulysin (Prt)] and their derivatives is mandatory to overcome supply problems hampering clinical development. We tested the anti-angiogenic efficacy of Prt and seven of its derivatives in comparison to tubulysin A (TubA).

EXPERIMENTAL APPROACH

The compounds were tested in cellular angiogenesis assays (proliferation, cytotoxicity, cell cycle, migration, chemotaxis, tube formation) and in vitro (tubulin polymerization). The efficacy of Prt was also tested in vivo in a murine subcutaneous tumour model induced with HUH7 cells; tumour size and vascularization were measured.

KEY RESULTS

The anti-angiogenic potency of all the compounds tested ran parallel to their inhibition of tubulin polymerization in vitro. Prt showed nearly the same efficacy as TubA (EC(50) in low nanomolar range in all cellular assays). Some modifications in the Prt molecule caused only a moderate drop in potency, while others resulted in a dramatic loss of action, providing initial insight into structure-activity relations. In vivo, Prt completely prevented tumour growth and reduced vascular density to 30%.

CONCLUSIONS AND IMPLICATIONS

Prt, a chemically accessible precursor of some tubulysins is a highly attractive anti-angiogenic compound both in vitro and in vivo. Even more simplified derivatives of this compound still retain high anti-angiogenic efficacy.

Expression of epidermal growth-factor receptor correlates with metastatic potential of 13762nf rat mammary adenocarcinoma cells

Increased expression of EGFR in metastases of human mammary carcinoma as compared to cells of the primary cancer suggests a contribution of EGFR to mammary carcinoma metastasis. To test for a positive correlation, we investigated 13762NF rat mammary adenocarcinoma cloned tumor cell lines of high (MTLn3) or low (MTC) metastatic potential. While MTC cells expressed barely detectable amounts of EGFR, MTLn3 cells expressed readily detectable levels of receptor. This was demonstrated in Northern blot analysis, in immunoprecipitation studies using metabolically labeled whole cell lysates and in Western blot analysis of membrane fractions. Cross-linking of radiolabeled ligand to intact cells identified on both cell types specific binding to a 170 kd protein, however, at much lower levels on low-metastatic MTC cells and not in sufficient amounts to estimate receptor numbers by Scatchard analysis. In contrast, Scatchard plot analysis of I-125-EGF binding to MTLn3 cells revealed the expression of about 10,000 high and 46,000 low affinity sites. Both cell lines expressed the ligand in comparable amounts as was demonstrated by using a specific rat TGFalpha cDNA probe in Northern blot and an antibody recognising membrane bound TGF in FACS analysis. Adhesion of MTC cells to immobilized collagen or fibronectin was rapid reaching 50% after 30 min while control MTLn3 cells demonstrated lower adhesion to collagen. Addition of 10 ng/ml EGF increased the rate and the maximal adhesion of MTLn3 cells to collagen G, while the adhesion kinetics of MTC cells to collagen G or fibronectin were unaffected.

Antiinflammatory properties of a plant-derived nonsteroidal, dissociated glucocorticoid receptor modulator in experimental autoimmune encephalomyelitis

Compound A (CpdA), a plant-derived phenyl aziridine precursor, was recently characterized as a fully dissociated nonsteroidal antiinflammatory agent, acting via activation of the glucocorticoid receptor, thereby down-modulating nuclear factor-kappaB-mediated transactivation, but not supporting glucocorticoid response element-driven gene expression. The present study demonstrates the effectiveness of CpdA in inhibiting the disease progress in experimental autoimmune encephalomyelitis (EAE), a well-characterized animal model of multiple sclerosis. CpdA treatment of mice, both early and at the peak of the disease, markedly suppressed the clinical symptoms of EAE induced by myelin oligodendrocyte glycoprotein peptide immunization. Attenuation of the clinical symptoms of EAE by CpdA was accompanied by reduced leukocyte infiltration in the spinal cord, reduced expression of inflammatory cytokines and chemokines, and reduced neuronal damage and demyelination. In vivo CpdA therapy suppressed the encephalogenicity of myelin oligodendrocyte glycoprotein peptide-specific T cells. Moreover, CpdA was able to inhibit TNF- and lipopolysaccharide-induced nuclear factor-kappaB activation in primary microglial cells in vitro, in a differential mechanistic manner as compared with dexamethasone. Finally, in EAE mice the therapeutic effect of CpdA, in contrast to that of dexamethasone, occurred in the absence of hyperinsulinemia and in the absence of a suppressive effect on the hypothalamic-pituitary-adrenal axis. Based on these results, we propose CpdA as a compound with promising antiinflammatory characteristics useful for therapeutic intervention in multiple sclerosis and other neuroinflammatory diseases.