Abstract P3-06-02: Tackling bone metastatic breast cancer growth with novel bone-seeking matrix metalloproteinase-2 inhibitors

Background. Despite medical advances, currently there is no treatment for breast to bone metastasis. The progression of bone metastatic breast cancer is critically dependent on interactions with the surrounding microenvironment. Therefore, identifying the underpinning molecular mechanisms is vital for the development of new therapies.

Rationale. Gene expression analysis and validation in human and murine specimens of bone metastases revealed matrix metalloproteinases, such as MMP-2, are highly expressed in the bone metastatic microenvironment. Genetic ablation of MMP-2 demonstrated the importance of this MMP in driving the growth of the osteolytic bone metastatic breast cancer by regulating the bioavailability of transforming growth factor β (TGFβ). These data support the rationale for the development of a highly specific MMP-2 inhibitor for the eradication of active bone metastatic breast cancer.

Methods. We utilized a novel chemical approach to synthesize bone seeking MMP inhibitors (BMMPIs) on a bisphosphonic backbone, with specificity for MMP-2 in the nanomolar range (IC50=140 nM).

In vitro, we tested the effect of BMMPIs at varying doses (1nM-100μM) on the viability of the major cellular components of the cancer-bone microenvironment, namely breast cancer cells (PyMT, 4T1), osteoblasts (MC3T3) and osteoclasts (primary monocytes and RAW 264.7). In vivo, mice were intratibially inoculated with either luciferase expressing 4T1 or PyMT (1x105) cells. Mice (n=10/group) then received vehicle, zoledronate (1 mg/kg) or BMMPIs (1 mg/kg). Tumor growth was determined via luminescence quantitation. Cancer induced bone disease was measured ex vivo by μCT, Xray and histomorphometry. MMP activity in vivo and ex vivo was determined via specific activatable MMP probes. Pharmacokinetic and pharmacodynamic studies were performed. Plasma and bone marrow supernatants were collected from PyMT-R221A tumor bearing mice treated with ML115 (5mg/Kg) at 0.25, 0.5, 1, 2, 4, 8, 24 hours and three weeks (n=3 mice/time point).

Currently, we are investigating the BMMPIs ability to impact the metastatic process through an in vivo model of intracardiac inoculation.

Results. BMMPIs significantly impacted the viability of breast cancer cells and osteoclasts in vitro (p<0.05) compared to control. In vivo, BMMPIs significantly reduced the growth of bone metastatic breast cancer compared to control and the standard of care bisphosphonate, zoledronate. MMP activity was also lower in the BMMPI treated groups (using tumor burden to normalize values). μCT/Xray/Histomorphometry analysis also illustrated the significant beneficial effects of the BMMPIs in reducing the size of osteolytic lesions (up to 80% by μCT; p<0.05).

ML115 is rapidly cleared from the plasma and accumulates selectively in the bone marrow microenvironment over time.

Conclusions. MMP-2 specific BMMPIs prevent bone metastatic breast cancer growth by impacting cancer cell viability and cancer induced osteolysis. Given that bisphosphonates are well tolerated in the clinical setting, we predict that BMMPIs could be translated to the clinical setting for the treatment and eradication of bone metastatic breast cancer.

Citation Format: Tauro M, Laghezza A, Tortorella P, Soliman HH, Lynch CC. Tackling bone metastatic breast cancer growth with novel bone-seeking matrix metalloproteinase-2 inhibitors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-06-02.

Abstract P6-12-10: Bone seeking matrix metalloproteinase-2 inhibitors prevent bone metastatic breast cancer growth

Bone metastasis is a common event during breast cancer progression. The resultant lesions are painful and currently, despite medical advances, are incurable. The progression of bone metastatic breast cancer is critically dependent on interactions with the surrounding microenvironment. Therefore, identifying the underpinning molecular mechanisms is vital for the development of new therapies.

Rationale: Gene expression analysis and validation in human and murine specimens of bone metastases revealed that matrix metalloproteinases, such as MMP-2, are highly expressed in the bone metastatic microenvironment and significantly associated with aggressive breast cancer and poorer overall survival. In bone, tumor or host derived MMP-2 contributes to breast cancer growth and does so by processing substrates including type I collagen and transforming growth factor beta (TGFβ) latency proteins. These data provide strong rationale for the application of MMP-2 inhibitors to treat the disease. However, in vivo, MMP-2 is systemically expressed. Therefore, to overcome potential toxicities noted with previous broad-spectrum MMP inhibitors (MMPIs), we used highly selective bisphosphonic based MMP-2 inhibitors (BMMPIs) that allowed for specific bone targeting.

Methods: We utilized a novel chemical approach to synthesize bone seeking MMP inhibitors (BMMPIs) on a bisphosphonic backbone, with specificity for MMP-2 in the nanomolar range (IC50=140 nM).

Results: In vitro, we tested the effect of BMMPIs at varying doses (1nM-100μM) on the viability of the major cellular components of the cancer-bone microenvironment, namely breast cancer cells, (PyMT, 4T1, MDA-MB-231, MCF-7), osteoblasts (MC3T3) and osteoclasts (primary monocytes and RAW 264.7). In vivo, we demonstrated using two bone metastatic models (PyMT-R221A-Luc and 4T1-Luc) that BMMPI treatment significantly reduced tumor growth and tumor associated bone destruction. Additionally, BMMPIs are superior in promoting tumor apoptosis compared to the standard of care bisphosphonate, zoledronate. MMP activity was also lower in the BMMPI treated groups (using tumor burden to normalize values). μCT/Xray/Histomorphometry analysis also illustrated the significant beneficial effects of the BMMPIs in reducing the size of osteolytic lesions (up to 80% by μCT; p<0.05). We demonstrated MMP-2 selective inhibition in the bone microenvironment using specific and broad spectrum MMP probes. Further, compared to zoledronate, BMMPI treated mice had significantly lower levels of TGFβ signaling and MMP generated type I collagen carboxy-terminal (ICTP) fragments. Taken together, our data show the feasibility of selective inhibition of MMPs in the bone metastatic breast cancer microenvironment.

Conclusions. MMP-2 specific inhibition was achieved in the bone microenvironment. BMMPIs significantly inhibit breast cancer growth in bone, they are able to induce breast cancer cell apoptosis and prevent cancer induced bone destruction. Given that bisphosphonates are well tolerated in the clinical setting, we predict that BMMPIs could be translated to the clinical setting for the treatment and eradication of bone metastatic breast cancer.

Citation Format: Tauro M, Laghezza A, Tortorella P, Lynch CC. Bone seeking matrix metalloproteinase-2 inhibitors prevent bone metastatic breast cancer growth [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-10.

Peripapillary RNFL Thickness Changes Evaluated with Spectral Domain Optical Coherence Tomography after Uncomplicated Macular Surgery for Epiretinal Membrane

PURPOSE

To evaluate the peripapillary RNFL (p-RNFL) thickness changes after vitrectomy for epiretinal membrane (ERM). The relationship between p-RNFL thickness change and visual function was assessed.

METHODS

Thirty-five eyes from 35 patients with ERM who underwent vitrectomy with internal limiting membrane (ILM) removal were included. Average p-RNFL and the four quadrants thickness were measured by spectral-domain optical coherence tomography (SD-OCT) before and at one, three, and six months after surgery.

RESULTS

At six months after surgery, p-RNFL thickness of the temporal and inferior quadrant was decreased in the operated eyes compared with fellow eyes (p<0.05). Pattern standard deviation (PSD) was higher than that of fellow eyes (p = 0.002). The temporal and inferior quadrant p-RNFL thickness showed a relationship with both best-corrected visual acuity (BCVA) outcome and the six-month PSD (p<0.05, respectively).

CONCLUSIONS

The selective decrease in the temporal and inferior p-RNFL thickness after vitrectomy for ERM removal could indicate inner retinal damage related to ILM peeling.

Abstract P6-16-02: Treatment of skeletal metastatic breast cancer with bone seeking matrix metalloproteinase inhibitors

Background. Breast to bone metastasis is a common event during breast cancer progression. The resultant lesions are painful and currently, despite medical advances, are incurable. The progression of bone metastatic breast cancer is critically dependent on interactions with the surrounding microenvironment. Therefore, identifying the underpinning molecular mechanisms is vital for the development of new therapies.

Rationale. Gene expression analysis and validation in human and murine specimens of bone metastases revealed matrix metalloproteinases, such as MMP-2, are highly expressed in the bone metastatic microenvironment. Genetic ablation of MMP-2 demonstrated the importance of this MMP in driving the growth of the osteolytic bone metastatic breast cancer by regulating the bioavailability of transforming growth factor β (TGFβ). These data support the rationale for the development of a highly specific MMP-2 inhibitor for the eradication of active bone metastatic breast cancer.

Methods. Given that previous broad-spectrum MMP inhibitor (MMPI) trials were unsuccessful due to dose limiting systemic side effects, we utilized a novel chemical approach to synthesize bone seeking MMP inhibitors (BMMPIs) on a bisphosphonic backbone, with specificity for MMP-2 in the nanomolar range (IC50=140 nM). In vitro, we tested the effect of BMMPIs at varying doses (1nM-100μM) on the viability of the major cellular components of the cancer-bone microenvironment, namely breast cancer cells (PyMT, 4T1), osteoblasts (MC3T3) and osteoclasts (primary monocytes and RAW 264.7). In vivo, mice were intratibially inoculated with either luciferase expressing 4T1 or PyMT (1x105) cells. Mice (n=10/group) then received vehicle, zoledronate (1 mg/kg) or BMMPIs (1 mg/kg). Tumor growth was determined via luminescence quantitation. Cancer induced bone disease was measured ex vivo by μCT, Xray and histomorphometry. MMP activity in vivo and ex vivo was determined via specific activatable MMP probes.

Results. BMMPIs significantly impacted the viability of breast cancer cells and osteoclasts in vitro (p&lt;0.05) compared to control. In vivo BMMPIs significantly reduced the growth of bone metastatic breast cancer compared to control and the standard of care bisphosphonate, zoledronate. MMP activity was also lower in the BMMPI treated groups (using tumor burden to normalize values). μCT/Xray/Histomorphometry analysis also illustrated the significant beneficial effects of the BMMPIs in reducing the size of osteolytic lesions (up to 80% by μCT; p&lt;0.05).

Conclusions. MMP-2 specific BMMPIs prevent bone metastatic breast cancer growth by impacting cancer cell viability and cancer induced osteolysis. Given that bisphosphonates are well tolerated in the clinical setting, we predict that BMMPIs could be translated to the clinical setting for the treatment and eradication of bone metastatic breast cancer.

Citation Format: Tauro M, Laghezza A, Tortorella P, Lynch CC. Treatment of skeletal metastatic breast cancer with bone seeking matrix metalloproteinase inhibitors. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-16-02.

Magnetic resonance imaging correlates of physical disability in relapse onset multiple sclerosis of long disease duration

Background:

Understanding long-term disability in multiple sclerosis (MS) is a key goal of research; it is relevant to how we monitor and treat the disease.

Objectives:

The Magnetic Imaging in MS (MAGNIMS) collaborative group sought to determine the relationship of brain lesion load, and brain and spinal cord atrophy, with physical disability in patients with long-established MS.

Methods:

Patients had a magnetic resonance imaging (MRI) scan of their brain and spinal cord, from which we determined brain grey (GMF) and white matter (WMF) fractional volumes, upper cervical spinal cord cross-sectional area (UCCA) and brain T2-lesion volume (T2LV). We assessed patient disability using the Expanded Disability Status Scale (EDSS). We analysed associations between EDSS and MRI measures, using two regression models (dividing cohort by EDSS into two and four sub-groups).

Results:

In the binary model, UCCA (p < 0.01) and T2LV (p = 0.02) were independently associated with the requirement of a walking aid. In the four-category model UCCA (p < 0.01), T2LV (p = 0.02) and GMF (p = 0.04) were independently associated with disability.

Conclusions:

Long-term physical disability was independently linked with atrophy of the spinal cord and brain T2 lesion load, and less consistently, with brain grey matter atrophy. Combinations of spinal cord and brain MRI measures may be required to capture clinically-relevant information in people with MS of long disease duration.

TH17-Driven Inflammation is Present in All Clinical Forms of Multiple Sclerosis; Disease Quiescence is Associated with Gata3-Expressing Cells

Multiple Sclerosis (MS) presents in a variety of clinical forms associated with a diverse grade of neurological impairment, different prognosis and, possibly, multiple pathogenic mechanisms. Thus, whereas relapsing-remitting (RR) MS appears to be largely driven by inflammatory processes, neurodegeneration, partially independent from inflammation, drives primary progressive (PP) and secondary progressive (SP) MS. An extensive analysis of neuroinflammation in the different forms of MS was performed by evaluating immunophenotypic and functional parameters in MBP-stimulated T lymphocytes of 103 MS patients (26 benign (BE) MS, 30 RRMS, 33 SPMS and 14 PPMS) and 40 healthy controls (HC). Results showed that: i) IL-17-producing and RORC/γt-expressing CD4+ T cells (TH17 lymphocytes), as well as IL-6 expressing CD14+ cell were augmented in all patients; ii) IL-22-expressing cells were increased in all forms of MS with the exception of PPMS; iii) TGF-β-expressing B cells were increased only in RRMS; and iv) GATA3-, NFATc-1, IL-13-, and IL-25-expressing cells (TH2 lymphocytes) were augmented in RRMS and BEMS patients alone. Data herein indicate a pivotal pathogenic role of TH17-driven inflammation in all clinical forms of MS and suggest that control over disease (RRMS and BEMS) is associated not with lack of inflammation per se, but rather with the activation of immune-mediated anti-inflammatory mechanisms. These results could help the design of novel diagnostic and therapeutic approaches.

New 2-(aryloxy)-3-phenylpropanoic acids as peroxisome proliferator-activated receptor α/γ dual agonists able to upregulate mitochondrial carnitine shuttle system gene expression

The preparation of a series of 2-(aryloxy)-3-phenylpropanoic acids, resulting from the introduction of different substituents into the biphenyl system of the previously reported peroxisome proliferator-activated receptor α/γ (PPARα/γ) dual agonist 1, allowed the identification of new ligands with higher potency on PPARα and fine-tuned moderate PPARγ activity. For the most promising stereoisomer (S)-16, X-ray and calorimetric studies in PPARγ revealed, at high ligand concentration, the presence of two molecules simultaneously bound to the receptor. On the basis of these results and docking experiments in both receptor subtypes, a molecular explanation was provided for its different behavior as a full and partial agonist of PPARα and PPARγ, respectively. The effects of (S)-16 on mitochondrial acylcarnitine carrier and carnitine-palmitoyl-transferase 1 gene expression, two key components of the carnitine shuttle system, were also investigated, allowing the hypothesis of a more beneficial pharmacological profile of this compound compared to the less potent PPARα agonist fibrates currently used in therapy.

Selective Diffusion Changes of The Visual Pathways in Patients with Migraine: A 3-T Tractography Study

Using diffusion tensor (DT) tractography, we quantified optic radiation (OR) structural changes in seven migraine patients with (MA) and eight without visual aura (MoA) and their relation to clinical manifestations and T2-visible burden. The corticospinal tract and the corpus callosum were studied as ‘control’ white matter (WM). No difference was found for any of the WM fibre bundles metrics between controls and MoA patients. MA patients had reduced average fractional anisotropy (FA) of both OR compared with controls and reduced average FA of the right OR compared with MoA patients. They also showed higher right OR mean diffusivity than controls. OR metrics were not correlated with clinical and magnetic resonance imaging (MRI) metrics. DT tractography reveals OR changes in MA patients that might represent a phenotypic biomarker of the disease given the lack of correlation with clinical and structural MRI metrics.

Restless legs syndrome is a common finding in multiple sclerosis and correlates with cervical cord damage

In this prospective study, we estimated the prevalence of restless legs syndrome (RLS) in multiple sclerosis (MS) patients, and compared the extent of brain and cervical cord damage between patients with and without RLS using conventional and diffusion tensor magnetic resonance imaging (MRI). Eighty-two consecutive MS patients were evaluated. Each patient underwent a medical history interview, a neurological examination and brain/cervical cord MRI. Global and regional dual-echo lesion load (LL), number of cervical cord lesions, mean diffusivity (MD) and fractional anisotropy (FA) histograms metrics of the normal-appearing tissues of the brain and cervical cord were assessed. Thirty subjects had RLS; they showed a higher Expanded Disability Status Scale score than patients without. No difference between the two groups was found in whole brain, cerebellar and brainstem T(2)-LLs; MD and FA histograms derived metrics of the normal appearing brain tissues; basal ganglia MD; number of cervical cord lesions and cord MD histograms derived metrics. Cervical cord average FA was significantly reduced in MS patients with RLS compared to those without. RLS symptoms are very common in MS. This form of RLS should be considered as symptomatic. Higher disability and cervical cord damage represent a significant risk factor for RLS in MS patients.

A multiparametric brain and cord MR imaging study of a patient with Hirayama disease

In this study, we used a multiparametric MR imaging approach to assess a patient with Hirayama disease (HD). We found that cervical cord damage extends beyond cord T2-visible lesions. We also showed an altered pattern of cortical activations during movements of clinically unaffected limbs. Whereas this study suggests a more widespread cord involvement in HD than seen on routine MR imaging, its cause remains unclear (vascular damage versus a primary lower motor neuron disease).

Diffusion tensor magnetic resonance imaging at 3.0 tesla shows subtle cerebral grey matter abnormalities in patients with migraine

BACKGROUND AND OBJECTIVE

Diffusion tensor (DT) magnetic resonance imaging (MRI) has the potential to disclose subtle abnormalities in the brain of migraine patients. This ability may be increased by the use of high field magnets. A DT MRI on a 3.0 tesla scanner was used to measure the extent of tissue damage of the brain normal appearing white (NAWM) and grey matter in migraine patients with T2 visible abnormalities.

METHODS

Dual echo, T1 weighted and DT MRI with diffusion gradients applied in 32 non-collinear directions were acquired from 16 patients with migraine and 15 sex and age matched controls. Lesion load on T2 weighted images was measured using a local thresholding segmentation technique, and brain atrophy assessed on T1 weighted images using SIENAx. Mean diffusivity and fractional anisotropy histograms of the NAWM and mean diffusivity histograms of the grey matter were also derived.

RESULTS

Brain atrophy did not differ between controls and patients. Compared with healthy subjects, migraine patients had significantly reduced mean diffusivity histogram peak height of the grey matter (p=0.04). No diffusion changes were detected in patients' NAWM. In migraine patients, no correlation was found between T2 weighted lesion load and brain DT histogram derived metrics, whereas age was significantly correlated with grey matter mean diffusivity histogram peak height (p=0.05, r=-0.52).

CONCLUSIONS

DT MRI at high field strength discloses subtle grey matter damage in migraine patients, which might be associated with cognitive changes in these patients.

MRI quantification of gray and white matter damage in patients with early–onset multiple sclerosis

BACKGROUND AND OBJECTIVE

Contrary to what happens in adult-onset multiple sclerosis (MS), in a previous preliminary magnetic resonance imaging (MRI) study we showed only subtle normal-appearing brain tissue changes in patients with earlyonset MS. Our objective was to evaluate the presence and extent of tissue damage in the brain normalappearing white matter (NAWM) and gray matter (GM) from a larger population of patients with earlyonset MS.

METHODS

Using diffusion tensor (DT) and magnetization transfer (MT) MRI, we obtained DT and MT ratio (MTR) maps of the NAWM and GM from 23 patients with early-onset MS and 16 sex- and age-matched healthy volunteers.

RESULTS

Compared with healthy volunteers, patients with early-onset MS had significantly increased average MD (p = 0.02) and FA peak height (p = 0.007) and decreased average FA (p <0.0001) of the NAWM. Brain dual-echo lesion load was significantly correlated with average FA (r = -0.48, p = 0.02) and with FA peak height (r = 0.45, p = 0.03) of the NAWM. No MTR and diffusion changes were detected in the GM.

CONCLUSIONS

This study confirms the paucity of the 'occult' brain tissue damage in patients with earlyonset MS. It also suggests that in these patients GM is spared by the disease process and that NAWM changes are likely to be secondary to Wallerian degeneration of fibers passing through macroscopic lesions.

Evaluation of a penicillin G acylase-based chiral stationary phase towards a series of 2-aryloxyalkanoic acids, isosteric analogs and 2-arylpropionic acids

The chiral recognition properties of a new chiral stationary phase based on immobilized penicillin G acylase were investigated using 35 acidic racemates. Twenty-seven compounds were resolved with high separation factors. The influences of mobile phase pH, type of organic modifier and ionic strength on enantioselective retention were studied. The most important tool for affecting the enantioselectivity was the mobile phase pH and interestingly the retention order of the enantiomers of some analytes could be controlled by this parameter. The analysis time for resolving enantiomers could be adjusted with a minor decrease in enantioselectivity using a high ionic strength mobile phase buffer while both retention and enantioselectivity decreased by adding organic modifier to the mobile phase. Displacement studies have demonstrated that the enzymatically active site and the chiral adsorption site overlap.

Gating of myotonic Na channel mutants defines the response to mexiletine and a potent derivative

BACKGROUND

Myotonia and periodic paralysis caused by sodium channel mutations show variable responses to the anti-myotonic drug mexiletine.

OBJECTIVE

To investigate whether variability among sodium channel mutants results from differences in drug binding affinity or in channel gating.

METHODS

Whole-cell sodium currents (I(Na)) were recorded in tsA201 cells expressing human wild-type (WT) and mutant skeletal muscle sodium channels (A1156T, hyperkalemic periodic paralysis; R1448C, paramyotonia congenita; G1306E, potassium-aggravated myotonia).

RESULTS

At a holding potential (hp) of -120 mV, mexiletine produced a tonic (TB, 0.33 Hz) and a use-dependent (UDB, 10 Hz) block of peak I(Na) with a potency following the order rank R1448C > WT approximately equal A1156T > G1306E. Yet, when assayed from an hp of -180 mV, TB and UDB by mexiletine were similar for the four channels. The different midpoints of channel availability curves found for the four channels track the half-maximum inhibitory value (IC50) measured at -120 mV. Thus differences in the partitioning of channels between the closed and fast-inactivated states underlie the different IC50 measured at a given potential. The mexiletine-derivative, Me7 (alpha-[(2-methylphenoxy)methyl]-benzenemethanamine), behaved similarly but was approximately 5 times more potent than mexiletine. Interestingly, the higher drug concentrations ameliorated the abnormally slower decay rate of myotonic I(Na).

CONCLUSIONS

These results explain the basis of the apparent difference in block of mutant sodium channels by mexiletine and Me7, opening the way to a more rationale drug use and to design more potent drugs able to correct specifically the biophysical defect of the mutation in individual myotonic patients.

Carboxylic acids and skeletal muscle chloride channel conductance: effects on the biological activity induced by the introduction of an aryloxyalkyl group alpha to the carboxylic function of 4-chloro-phenoxyacetic acid

2-(4-Chloro-phenoxy)propanoic and 2-(4-chloro-phenoxy)butanoic acids are compounds known to block chloride membrane conductance in rat striated muscle by interaction with a specific receptor. In the present study, a series of chiral analogues has been prepared and tested to evaluate the influence of a second aryloxy moiety introduced in the side-chain at a variable distance from the stereogenic centre. The results show that this chemical modification is detrimental for biological activity which, however, is increased by lengthening the alkyl chain up to three methylenic groups, then decreases to remain constant in the next analogues of the series. A possible explanation for this is proposed on the basis of steric effects and/or different approach of the molecules to the receptor.