Mobile-phone-based e-diary derived patient reported outcomes: Association with clinical disease activity, psychological status and quality of life of patients with multiple sclerosis

BACKGROUND

The applicability of mobile digital technology to promote clinical care of people with multiple sclerosis (pwMS) is gaining increased interest as part of the implementation of patient-centered approaches. We aimed at assessing adherence to a smartphone-based e-diary, which was designed to collect patient-reported outcomes (PROs). Secondary objectives were to evaluate the construct and predictive validity of e-diary derived PROs and to explore the various factors that were associated with changes in PROs over time.

MATERIALS AND METHODS

In this observational cohort study patients downloaded an MS tailored e-diary into their personal smartphones. Report of PROs was enquired once monthly for a period of one year through a smartphone-based application, using previously validated tools. An e-diary derived bodily function summary score (eBF) was defined as the sum of scores depicting vision, limbs function, pain, bowl/ bladder dysfunction, pseudobulbar affect and spasticity. Multiple linear regression and analysis of covariance were used to determine the association between PROs, clinician-reported outcomes (ClinROs) of disease activity and quality of life (QoL). Regression coefficient analysis was used to compare the slope of change in eBF before and after a relapse.

RESULTS

97 pwMS downloaded the e-diary [Female: 64 (66%), EDSS 3.4±2.1]. 76 patients (78%) completed the 12-month study period. 53 patients (55%) submitted ≥75% of requested surveys. Anxiety was negatively associated with adherence to periodic PROs assessments by the e-diary. E-diary derived PROs were significantly correlated with corresponding functional system scores (0.38< r <0.8, P<0.001). eBF score significantly predicted QoL (β = -0.36, P = 0.001) while EDSS did not. Change in eBF score over time was independently associated with the occurrence of an MS relapse (F = 4.4, P = 0.04), anxiety (F = 6.4, P = 0.01) and depression (F = 5.1, P = 0.03). Individual regression slopes of eBF scores were significantly higher pre-relapse than post-relapse (3.0±3.3 vs. -0.8±2.0, P = 0.007).

CONCLUSION

Adherence of pwMS to recording in an e-diary collecting PROs was high. Changes in e-diary derived PROs over time predict clinical MS relapses on the group level and thus carry the potential of usage in clinical research as well as for improved MS care in real world setting.

Beliefs about medication as predictors of medication adherence in a prospective cohort study among persons with multiple sclerosis

BACKGROUND

Though adherence to disease-modifying therapies (DMTs) among persons with multiple sclerosis (PwMS) varies and is often below 80%, only few prospective studies on adherence examined predictors beyond demographic and clinical characteristics.

OBJECTIVES

Identify antecedents to adherence and persistence to DMT in a prospective design among PwMS.

METHODS

PwMS (n = 186) were prospectively assessed at three time points: baseline, 6 (Time 1) and 12 months later (Time 2). Clinical, demographic information and patient-reported medication beliefs, illness perceptions, medication habits, perceived health and affect were surveyed in-person. Adherence and persistence were assessed by a combination of self-reports and retrospective review of medication claims.

FINDINGS

PwMS were 69.9% (Time 1) and 71% (Time 2) adherent to their DMTs and 64.5.9% were persistent. Beliefs about Medications were consistently predictive at both time points (baseline to Time 1 and Time 1 to Time 2) of medication adherence and persistence whereas other perceptions were predictive in some analyses; clinical and demographic characteristics were mostly not predictive of adherence nor persistence. The prospective association of beliefs about medication with adherence held also in multivariate analyses (OR = 0.88, 95% CI 0.78-0.99, p = 0.029).

CONCLUSIONS

Adherence and persistence are predicted by medication beliefs of PwMS. As medication beliefs are modifiable, they should be assessed periodically and targeted as a focus of tailored interventions aimed to improve adherence and consequently health outcomes in PwMS.

REGISTRATION

Clinical trials registry # NCT02488343 , date: 06/08/2015.

Concordance Between Persons with Multiple Sclerosis and Treating Physician on Medication Effects and Health Status

BACKGROUND

As the number of treatment options for multiple sclerosis (MS) has expanded, alignment between physician and patient on effects of medication has emerged as important for medication persistence/discontinuation.

OBJECTIVE

To evaluate physician-patient agreement levels on medication effect and health status.

METHODS

Persons with MS (PwMS) (n=71) participated in a cross-sectional study collecting their satisfaction (using the Treatment Satisfaction Questionnaire for Medication), intention to dis/continue treatment and global health perception; physicians assessed response to medication and global health status.

RESULTS

Concordance between PwMS' assessment of medication effectiveness and physician's assessment on response to medication, health status and EDSS were r _s= 0.50, r _s= 0.57 and r _s= -0.58, respectively.

CONCLUSION

The significant concordance attests to physician-patient effective communication and may contribute to improved medication adherence.

Mobile phone-based e-diary for assessment and enhancement of medications adherence among patients with multiple sclerosis

Background

Adherence to multiple sclerosis (MS) disease-modifying drugs (DMDs) is essential for realization of their optimal effectiveness and benefits.

Objective

To evaluate the usefulness and validity of a smartphone-based e-diary as a tool for adherence assessment as well as its effectiveness as a promoter of adherence to DMDs.

Methods

An MS tailored e-diary (MyMS&Me) reminded patients to take their DMDs on time. DMD intake was self-recorded in the e-diary by the participants. Three methods of adherence evaluation were compared: e-diary derived, retrospective self-reported, and the medication possession rate (MPR). The proportion of patients with poor adherence to DMDs (defined as MPR <80%) among e-diary users was compared with a control group without intervention.

Results

Sixty-two patients downloaded the e-diary (Female: 41 (66%), Expanded Disability Status Scale 3.2 ± 2.2) and 55 controls were enrolled. The median difference between e-diary-derived adherence and the MPR was –3% (95% limits of agreement: −53% to 12%). The median difference between retrospective self-reported adherence and the MPR was 0.3% (95% limits of agreement: −20% to 42%). The proportion of participants with poor adherence to DMDs was similar in the e-diary and control groups (10% vs. 13%, p = 0.6).

Conclusions

Substantial and clinically important disagreement between methods of medication adherence evaluation was noted. Smartphone reminders did not significantly improve the MPR of DMDs.

Multiple modality approach to assess adherence to medications across time in Multiple Sclerosis

BACKGROUND

Medication adherence is especially challenging in a chronic condition such as Relapsing Multiple Sclerosis (RMS). Medication adherence among persons with MS (PwMS) is usually assessed via a single measure, mostly electronic pharmacy records.

OBJECTIVES

Assess medication adherence in multiple modes across time among PwMS; examine consistency across time and associations between measures.

METHODS

PwMS (N = 194) were surveyed prospectively at three time points (baseline, 6 and 12 months later) and their health records and medication claims were retrospectively obtained. Adherence score was based on medication possession ratio (MPR) and two patient-reported outcome (PRO) measures. Electronic monitoring devices assessing medication adherence were also initiated.

RESULTS

MPR of each nonadherent PwMS, once compared to medical records containing prescription changes, was found as underestimating adherence. MPR was between the two PROs in identifying nonadherence and associations between the measures and across time was moderate (Kappa ranged 0.37-0.42). The use of electronic monitoring devices was not adopted by patients. A score indicated adherence as 66% and 64.9% at Time1 and Time 2, respectively, with 21.1% of PwMS nonadherent at both time points. Adherence did not vary significantly by DMT type.

CONCLUSIONS

Being a dynamic behavior, medication adherence should be repeatedly monitored by using multiple modalities and focused on in clinician-patient encounters, especially in chronic diseases such as MS, which requires long-term treatments. Applying PROs in monitoring medication adherence would facilitate implementation of Participatory Medicine and patient-centered strategies in MS care.

Exhaled Breath Markers for Nonimaging and Noninvasive Measures for Detection of Multiple Sclerosis

Multiple sclerosis (MS) is the most common chronic neurological disease affecting young adults. MS diagnosis is based on clinical characteristics and confirmed by examination of the cerebrospinal fluids (CSF) or by magnetic resonance imaging (MRI) of the brain or spinal cord or both. However, neither of the current diagnostic procedures are adequate as a routine tool to determine disease state. Thus, diagnostic biomarkers are needed. In the current study, a novel approach that could meet these expectations is presented. The approach is based on noninvasive analysis of volatile organic compounds (VOCs) in breath. Exhaled breath was collected from 204 participants, 146 MS and 58 healthy control individuals. Analysis was performed by gas-chromatography mass-spectrometry (GC-MS) and nanomaterial-based sensor array. Predictive models were derived from the sensors, using artificial neural networks (ANNs). GC-MS analysis revealed significant differences in VOC abundance between MS patients and controls. Sensor data analysis on training sets was able to discriminate in binary comparisons between MS patients and controls with accuracies up to 90%. Blinded sets showed 95% positive predictive value (PPV) between MS-remission and control, 100% sensitivity with 100% negative predictive value (NPV) between MS not-treated (NT) and control, and 86% NPV between relapse and control. Possible links between VOC biomarkers and the MS pathogenesis were established. Preliminary results suggest the applicability of a new nanotechnology-based method for MS diagnostics.

Diagnosis and Classification of 17 Diseases from 1404 Subjects via Pattern Analysis of Exhaled Molecules

We report on an artificially intelligent nanoarray based on molecularly modified gold nanoparticles and a random network of single-walled carbon nanotubes for noninvasive diagnosis and classification of a number of diseases from exhaled breath. The performance of this artificially intelligent nanoarray was clinically assessed on breath samples collected from 1404 subjects having one of 17 different disease conditions included in the study or having no evidence of any disease (healthy controls). Blind experiments showed that 86% accuracy could be achieved with the artificially intelligent nanoarray, allowing both detection and discrimination between the different disease conditions examined. Analysis of the artificially intelligent nanoarray also showed that each disease has its own unique breathprint, and that the presence of one disease would not screen out others. Cluster analysis showed a reasonable classification power of diseases from the same categories. The effect of confounding clinical and environmental factors on the performance of the nanoarray did not significantly alter the obtained results. The diagnosis and classification power of the nanoarray was also validated by an independent analytical technique, i.e., gas chromatography linked with mass spectrometry. This analysis found that 13 exhaled chemical species, called volatile organic compounds, are associated with certain diseases, and the composition of this assembly of volatile organic compounds differs from one disease to another. Overall, these findings could contribute to one of the most important criteria for successful health intervention in the modern era, viz. easy-to-use, inexpensive (affordable), and miniaturized tools that could also be used for personalized screening, diagnosis, and follow-up of a number of diseases, which can clearly be extended by further development.

Effect of Fampridine-PR (prolonged released 4-aminopyridine) on the manual functions of patients with Multiple Sclerosis

BACKGROUND

Persons with MS (PwMS) commonly present ambulatory and manual dysfunctions. While ambulation is recognized as important to PwMS, manual dysfunction is only lately gaining attention. Fampridine-PR was approved for MS ambulatory impairments. Anecdotal evidences indicate possible therapeutic effects on manual function.

OBJECTIVE

To comprehensively assess the effect of Fampridine-PR on manual functions of PwMS.

METHODS

Twenty six PwMS with ambulatory and manual dysfunction assessed before, 1 and 3months after treatment with Fampridine-PR, applying Timed 25-Foot Walk (T25FW) for ambulation while manual functions were evaluated by several tools addressing the International Classification of Functioning (ICF) concepts. This includes hand grip and pinch strength, 9 Hole Peg Test (9HPT), Arthritis Hand Function Test (AHFT), activities of daily life (ADL) tests, ABILHAND questionnaire and Computerized Penmanship Evaluation Tool (ComPET).

RESULTS

Fampridine-PR increased dominant hand grip and pinch strength 1month following treatment initiation by 12% and 10% (p<0.05), respectively. 9HPT improved by 11.3% after 3months of treatment (p<0.05%) and ABILHAND improved by 16% and 31% (p<0.05%) after 1 and 3months of treatment. Mean stroke duration in air of the name writing task improved by 21% (p<0.05) following 3months of treatment. T25FW results were similar to previous reports.

CONCLUSION

The results of this pilot study suggest that Fampridine-PR improves manual function of PwMS. Methods herein indicate that an integrative approach may be useful for evaluation of manual function in MS and in additional neurological diseases.

Vitamin D supplementation for patients with multiple sclerosis treated with interferon-beta: a randomized controlled trial assessing the effect on flu-like symptoms and immunomodulatory properties

BACKGROUND

Flu-like symptoms (FLS) are common side effects of interferon beta (IFN-β) treatment in patients with Multiple Sclerosis (PwMS) and are associated with post-injection cytokine surge. We hypothesized that vitamin D3 supplementation would ameliorate FLS by decreasing related serum cytokines' levels.

METHODS

In a randomized, double blind study of 45 IFNβ-treated PwMS, 21 patients were assigned to 800 IU of vitamin D3 per day (low dose), while 24 patients received 4,370 IU per day (high dose) for one year. FLS were assessed monthly by telephonic interviews. Serum levels of 25-hydroxy-D (25-OH-D), calcium, PTH, IL-17, IL-10 and IFN-γ were measured periodically. EDSS, relapses, adverse events and quality of life (QoL) were documented.

RESULTS

25-OH-D levels increased to a significantly higher levels and PTH levels decreased in the high dose group. There was no significant change in FLS. IL-17 levels were significantly increased in the low dose group, while patients receiving high dose vitamin D had a heterogeneous IL-17 response. No significant differences in relapse rate, EDSS, QoL, serum IL-10 and IFNγ were found. Hypercalcemia or other potential major adverse events were not observed.

CONCLUSION

Vitamin D supplementation to IFN-β treated PwMS, at the doses used, seems safe and associated with dose-dependent changes in IL-17 serum levels, while not affecting IFN-β related FLS.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT01005095.

The ubiquitin-proteasome pathway regulates claudin 5 degradation

The tight junctions (TJs) form continuous intracellular contacts, which help create selective barriers in epithelial and endothelial cell layers. The structures created by the TJs are very dynamic and can be rapidly remodeled in response to physiological and pathological signals. Claudin 5 is a membranal TJ protein which plays a critical role in determining the permeability of endothelial barriers. We describe the regulation of claudin 5 degradation by the ubiquitin-proteasome system (UPS). Our results indicate that claudin 5 has a relatively short half-life and can be polyubiquitinated on lysine 199. This ubiquitination appears to trigger the proteasome-dependent degradation of claudin 5. Other mechanisms also seem to be involved in the post-translational regulation of claudin 5, including a ubiquitin-independent and probably indirect lysosomal-dependent pathway. These findings provide evidence for the involvement of the UPS in the regulation of claudin 5 levels, and set the stage for further research to determine the involvement of this pathway in the modulation of the properties of TJs and cell-layer barriers.

Tight junction proteins expression and modulation in immune cells and multiple sclerosis

The tight junction proteins (TJPs) are major determinants of endothelial cells comprising physiological vascular barriers such as the blood-brain barrier, but little is known about their expression and role in immune cells. In this study we assessed TJP expression in human leukocyte subsets, their induction by immune activation and modulation associated with autoimmune disease states and therapies. A consistent expression of TJP complexes was detected in peripheral blood leukocytes (PBLs), predominantly in B and T lymphocytes and monocytes, whereas the in vitro application of various immune cell activators led to an increase of claudin 1 levels, yet not of claudin 5. Claudins 1 and 5 levels were elevated in PBLs of multiple sclerosis (MS) patients in relapse, relative to patients in remission, healthy controls and patients with other neurological disorders. Interestingly, claudin 1 protein levels were elevated also in PBLs of patients with type 1 diabetes (T1D). Following glucocorticoid treatment of MS patients in relapse, RNA levels of JAM3 and CLDN5 and claudin 5 protein levels in PBLs decreased. Furthermore, a correlation between CLDN5 pre-treatment levels and clinical response phenotype to interferon-β therapy was detected. Our findings indicate that higher levels of leukocyte claudins are associated with immune activation and specifically, increased levels of claudin 5 are associated with MS disease activity. This study highlights a potential role of leukocyte TJPs in physiological states, and autoimmunity and suggests they should be further evaluated as biomarkers for aberrant immune activity and response to therapy in immune-mediated diseases such as MS.

Cathepsins and their endogenous inhibitors cystatins: expression and modulation in multiple sclerosis

Cathepsins are involved in a variety of physiological processes including antigen processing and presentation and extracellular matrix degradation. In the present study, we evaluated whether expression levels of cathepsins S and B and their inhibitors cystatins B and C are affected by multiple sclerosis (MS) disease state (relapse and remission) and therapies (interferon-β[IFN-β] and the glucocorticoid [GC] methylprednisolone), and whether they are associated with the IFN-β response phenotype. Real-time PCR was employed to compare RNA expression levels in peripheral blood leucocytes (PBLs) and ELISA to determine serum protein levels of MS patients and matched healthy individuals. Cathepsin S RNA was higher in MS patients in the relapse state compared to controls (by 74%, P= 3 × 10⁻⁵, n= 30 versus n= 18) with a similar increase observed in serum (66%, P= 0.002, n= 18 versus n= 20). GC treatment reduced cathepsin S levels in PBL RNA (by 44%, P= 6 × 10⁻⁶, n= 27) and serum proteins (by 27%, P= 1 × 10⁻⁵, n= 26), reduced the serum protein levels of pro-cathepsin B (by 8%, P= 0.0007, n= 23), and in parallel increased the serum levels of their inhibitor cystatin C (by 82%, P= 8 × 10⁻⁶, n= 26). IFN-β therapy significantly elevated the RNA levels (n= 16) of cathepsin B (by 16%, P= 0.03), cystatin B (44%, P= 0.004) and cystatin C (48%, P= 0.011). In the serum, only cathepsin S levels were reduced by IFN-β (16%, P= 0.006, n= 25). Interestingly, pre-treatment serum cathepsin S/cystatin C ratio was higher in ‘good responders’ to IFN-β therapy compared to patients without a good response (by 94%, P= 0.003). These results suggest that cathepsin S and cystatin C may contribute to disease activity in MS, specifically in a subgroup of patients that are responsive to IFN-β therapy, and that these proteins should be further evaluated as biomarkers in MS.

Detection of multiple sclerosis from exhaled breath using bilayers of polycyclic aromatic hydrocarbons and single-wall carbon nanotubes

A cross-reactive array of polycyclic aromatic hydrocarbons and single wall carbon nanotube bilayers was designed for the detection of volatile organic compounds (tentatively, hexanal and 5-methyl-undecane) that identify the presence of disease in the exhaled breath of patients with multiple sclerosis. The sensors showed excellent discrimination between hexanal, 5-methyl-undecane, and other confounding volatile organic compounds. Results obtained from a clinical study consisting of 51 volunteers showed that the sensors could discriminate between multiple sclerosis and healthy states from exhaled breath samples with 85.3% sensitivity, 70.6% specificity, and 80.4% accuracy. These results open new frontiers in the development of a fast, noninvasive, and inexpensive medical diagnostic tool for the detection and identification of multiple sclerosis. The results could serve also as a launching pad for the discrimination between different subphases or stages of multiple sclerosis as well as for the identification of multiple sclerosis patients who would respond well to immunotherapy.

Immunomodulation by chronobiologically-based glucocorticoids treatment for multiple sclerosis relapses

This study compares the effects of daytime versus nighttime intravenous glucocorticoid treatment of multiple sclerosis (MS) relapses for several immune indicators. The levels of serum CRP, TNFalpha, ESR, MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined at trial entry and at day 7 post therapy initiation in 35 MS patients. Serum MMP-9 protein levels were differentially affected by treatment regimen, and were significantly lower after nighttime treatment. Both treatment protocols led to a similar reduction of ESR, CRP and TNFalpha. These findings provide preliminary characterization of biomarkers in the application of chronobiology-based glucocorticoid therapeutics in MS and other immune disorders.

Chronotherapy using corticosteroids for multiple sclerosis relapses

BACKGROUND

The activity of the immune system displays a circadian rhythm. In diseases characterised by aberrant immune activity, chronotherapy (a treatment regimen tailored to diurnal body rhythms) may increase the efficiency, safety and tolerability of drugs.

AIM

To compare the outcomes of intravenous corticosteroid administration during the day or night, for treatment of acute multiple sclerosis relapses.

METHODS

17 patients with multiple sclerosis were included in the study. Clinical assessment of disability was performed at trial entry, and at days 7 and 30 from the initiation of treatment. Adverse events and preference of night-time versus daytime treatment were assessed at the end of the treatment course.

RESULTS

After night-time treatment, clinical recovery was significantly (p<0.001) enhanced and the mean number of side effects was significantly (p = 0.007) lower. Furthermore, most patients expressed a preference for night-time versus daytime treatment.

CONCLUSIONS

The study suggests a potential benefit for implementation of chronotherapy using steroid treatment for acute multiple sclerosis relapse, with implications for other immune-mediated disorders.

Modulation of matrix metalloproteinase-9 (MMP-9) secretion in B lymphopoiesis

The matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade the extracellular matrix, thus involved in cellular migration. The extent and role of MMPs secretion in primary non-transformed B cells, and specifically during early stages of development in the bone marrow (BM), has been barely unveiled. Herein, we investigated the secretion of MMP-9 during B lymphopoiesis and its modulation in response to different mitogens and cytokines. To do so, we used our BM culture system and well-studied mutated mouse models to isolate the different B cell populations. Our results show that MMP-9 is spontaneously secreted throughout B lymphopoiesis, and that the level of secreted MMP-9 is developmentally regulated. Using reverse transcription-PCR, we found that IFNbetaR is expressed throughout B cell development, while tumor necrosis factor (TNF)-alphaR-p55 and IFNgammaR expressions are initiated only at the pre-B stage. We found that TNFalpha stimulates MMP-9 secretion in transitional cells, whereas IFNs suppress MMP-9 secretion in immature cells. LPS and phorbol 12-myristate 13-acetate suppressed MMP-9 secretion in transitional cells, whereas LPS and concanavalin A stimulated MMP-9 secretion in mature B cells. We conclude that B lymphocyte development is accompanied with MMP-9 secretion and the developing cells are competent to modify this secretion upon different immune stimuli.

Serum anti-Glc(α1,4)Glc(α) antibodies as a biomarker for relapsing–remitting multiple sclerosis

There is an unmet need to develop specific biomarkers for multiple sclerosis (MS) to aid in the diagnosis, improve the management of patients and the monitoring of the effectiveness of treatment. We have screened serum from patients with relapsing-remitting MS (RRMS, n = 107) against a library of glycans on a glycan chip, and have found significantly higher levels of IgM anti-Glc(alpha1,4)Glc(alpha) antibodies (anti-Galpha4Galpha antibodies) than in patients suffering from other neurological diseases (OND, n = 50, p < 0.0001), and other autoimmune diseases (OAD, n = 27, p = 0.02). No significant differences were found relative to patients having primary progressive MS (n = 16). No significant differences were detected between the levels of IgM anti-Galpha4Galpha antibodies in sera from patients with RRMS in relapsing versus remitting state, and in patients treated with immunotherapy versus untreated patients. To test whether the highly significant difference in the levels of IgM anti-Galpha4Galpha between RRMS and OND group is due to general increase in IgM levels, we have measured total serum IgM in a subgroup of 62 MS and 48 OND patients. Although the total IgM was significantly lower in the OND than the RRMS group (p = 0.0007), analysis of covariance (ANCOVA) reveled no statistically significant relationship to the covariate (total IgM). Furthermore, following normalizing the values to total IgM the difference in the levels of IgM anti-Galpha4Galpha between the MS and OND groups was found highly significant (p < < 0.0001). The present findings support further assessment of serum anti-Galpha4Galpha antibodies as a potential biomarker for MS, which may confirm disease diagnosis and aid in its management.

Ca2+-induced changes in energy metabolism and viability of melanoma cells

Cancer cells are characterized by a high rate of glycolysis, which is their primary energy source. We show here that a rise in intracellular-free calcium ion (Ca2+), induced by Ca2+-ionophore A23187, exerted a deleterious effect on glycolysis and viability of B16 melanoma cells. Ca2+-ionophore caused a dose-dependent detachment of phosphofructokinase (EC 2.7.1.11), one of the key enzymes of glycolysis, from cytoskeleton. It also induced a decrease in the levels of glucose 1,6-bisphosphate and fructose 1,6-bisphosphate, the two stimulatory signal molecules of glycolysis. All these changes occurred at lower concentrations of the drug than those required to induce a reduction in viability of melanoma cells. We also found that low concentrations of Ca2+-ionophore induced an increase in adenosine 5'-triphosphate (ATP), which most probably resulted from the increase in mitochondrial-bound hexokinase, which reflects a defence mechanism. This mechanism can no longer operate at high concentrations of the Ca2+-ionophore, which causes a decrease in mitochondrial and cytosolic hexokinase, leading to a drastic fall in ATP and melanoma cell death. The present results suggest that drugs which are capable of inducing accumulation of intracellular-free Ca2+ in melanoma cells would cause a reduction in energy-producing systems, leading to melanoma cell death.

Taxol (paclitaxel) induces a detachment of phosphofructokinase from cytoskeleton of melanoma cells and decreases the levels of glucose 1,6-bisphosphate, fructose 1,6-bisphosphate and ATP

Glucose utilization through glycolysis, which is the primary energy source in cancer cells, is known to be controlled by allosteric regulators, as well as by reversible binding of glycolytic enzymes to cytoskeleton. Here we report of a novel mechanism of action of taxol (paclitaxel; Baccatin III N-benzyl-beta-phenylisoserine ester), the anti-microtubule agent with remarkable anticancer activity. We show that taxol affects both levels of regulation of glycolysis in melanoma cells; it decreases the levels of glucose 1,6-bisphosphate and fructose 1,6-bisphosphate, the two allosteric stimulatory signal molecules of glycolysis, and also causes a detachment of phosphofructokinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11), the rate-limiting enzyme of glycolysis, from the cytoskeleton of B16 melanoma cells. These effects of taxol were dose-dependent, and preceded the decrease in ATP levels and cell viability. Thus, taxol not only inhibits the essential dynamic processes of microtubule network, but also reduces glycolysis, through the novel mechanisms described here.

Detachment of glycolytic enzymes from cytoskeleton of melanoma cells induced by calmodulin antagonists

Glycolysis, which is the primary energy source in cancer cells, is known to be controlled by allosteric regulators, as well as by reversible binding of glycolytic enzymes to cytoskeleton. We have previously found that different calmodulin antagonists decrease the levels of allosteric activators of glycolysis, and reduce ATP content and cell viability in B16 melanoma cells. Here we report of a novel, additional, mechanism of action of calmodulin antagonists in melanoma cells. We show that these drugs cause a detachment of the glycolytic enzymes, phosphofructokinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) and aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13), from cytoskeleton of B16 melanoma cells. This effect was dose- and time-dependent, and preceded the decrease in cell viability. The detachment of glycolytic enzymes from cytoskeleton would reduce the provision of local ATP, in the vicinity of the cytoskeleton-membrane and would affect cytoskeleton structure. Since the cytoskeleton is being recognized as an important modulator of cell function, proliferation, differentiation and neoplasia, detachment of the glycolytic enzymes from cytoskeleton induced by calmodulin antagonists, as well as their reported inhibitory action on cell proliferation, make these drugs most promising agents in treatment of cancer.

Calmodulin antagonists decrease glucose 1,6-bisphosphate, fructose 1,6-bisphosphate, ATP and viability of melanoma cells

Glycolysis is known to be the primary energy source in cancer cells. We investigated here the effect of four different calmodulin antagonists: thioridazine (10-[2-(1-methyl-2-piperidyl) ethyl]-2-methylthiophenothiazine), CGS 9343B (1,3-dihydro-1-[1-[(4-methyl-4H,6H-pyrrolo[1,2-a] [4,1]-benzoxazepin-4-yl)methyl]-4-piperidinyl]-2 H-benzimidazol-2-one (1:1) maleate), clotrimazole (1-(alpha-2-chlorotrityl)imidazole) and bifonazole (1-(alpha-biphenyl-4-ylbenzyl)imidazole), on the levels of glucose 1,6-bisphosphate and fructose 1,6-bisphosphate, the two stimulatory signal molecules of glycolysis, and on ATP content and cell viability in B16 melanoma cells. We found that all four substances significantly reduced the levels of glucose 1,6-bisphosphate, fructose 1,6-bisphosphate and ATP, in a dose- and time-dependent manner. Cell viability was reduced in a close correlation with the fall in ATP. The decrease in glucose 1,6-bisphosphate and fructose 1,6-bisphosphate did not result from the cytotoxic effects of the calmodulin antagonists, since their content was already reduced before any cytotoxic effect was observed. These findings suggest that the fall in the levels of the two signal molecules of glycolysis, induced by the calmodulin antagonists, causes a reduction in glycolysis and ATP levels, which eventually leads to cell death. Since cell proliferation was also reported to be inhibited by calmodulin antagonists, these substances are most promising agents in treatment of cancer by inhibiting both cell proliferation and the glycolytic supply of ATP required for cell growth.

Effects of carbamylcholine and pyridostigmine on cytoskeleton-bound and cytosolic phosphofructokinase and ATP levels in different rat tissues

1. The effects of carbamylcholine (CaCh) (acetylcholine agonist) and pyridostigmine (Pyr) (acetylcholinesterase inhibitor), on the activity of cytoskeleton-bound and cytosolic phosphofructokinase (PFK), the rate-limiting enzyme in glycolysis, and ATP levels, were studied in rat tibialis anterior (TA) muscle, heart, and brain. 2. In the TA muscle, a marked (about three-fold) increase in the allosteric activity of cytosolic (soluble) PFK was found, 3-5 min following the injection of CaCh or Pyr. The intracellular distribution of the enzyme was not affected by both drugs. Stimulation of glycolysis in this muscle was also expressed by a significant increase in the concentrations of glycolytic intermediates and lactate. Glucose 1,6-bisphosphate (Glc-1,6-P2) levels were unchanged, whereas fructose-2,6-bisphosphate (Fru-2,6-P2) was increased. Glycogenolysis was also stimulated, as deduced from the decrease in glycogen content. The stimulation of glycolysis, induced by both drugs, was accompanied by an increase in ATP level in the TA muscle. 3. In contrast to the stimulatory action of CaCh or Pyr on glycolysis in the TA muscle, both drugs had no effect on cytosolic and cytoskeletal PFK in heart and brain. However, ATP content in both heart and brain was markedly reduced by these drugs, most probably due to their reported harmful effects on mitochondrial function, leading to tissue damage. 4. Electron microscopic studies of TA muscle and heart from rats treated with CaCh or Pyr, revealed severe damage of heart but no harmful effects on TA muscle, which is a muscle with high glycolytic and low oxidative capacity. The present experiments suggest that the accelerated glycolysis in this muscle induced by both drugs, supplies ATP, thus preventing muscle damage.

Effects of carbamylcholine and pyridostigmine on mitochondrial-bound hexokinase in skeletal muscle and heart

We show here that carbamylcholine (acetylcholine agonist) or pyridostigmine (acetylcholinesterase inhibitor), drugs which are widely used in medical treatments, exerted a rapid reduction in mitochondrial-bound hexokinase. This reduction was inversely proportional to the changes in glucose-6-phosphate levels in skeletal and heart muscle. Increased concentration of acetylcholine, occurring in various diseases or induced by acetylcholinesterase inhibitors, was reported to cause deterioration of mitochondrial function, resulting in heart and muscle damage. The present experiments suggest that the reduction in mitochondrial-bound hexokinase, which is closely linked to intramitochondrial oxidative metabolism, may play an important role in the mechanism which leads to tissue damage.