Development of methotrexate proline prodrug to overcome resistance by MDA-MB-231 cells

Investigating the effect of ligand structure on the anticancer properties of several new Co(II) complexes of vitaminB3-based phosphoramides

Nicotinamide, known as Vitamin-B3, has shown promising potential in improving various medical conditions. Carbacylamidophosphates (CAPh) are versatile phosphoramide ligands with a wide range of applications in both biochemistry and chemistry. Herein, to obtain compounds with enhanced anticancer activity and study the effect of the structure on this activity, four new Co(II) complexes of vitaminB3-based CAPh ligands with the formula of CoCl2[3-NC5H4CONHPO(NC5H10)2]2(C1), CoCl2[3-NC5H4CONHPO(NC5H9CH3)2]2(C2), CoCl2[3-NC5H4CONHPO(NC6H12)2]2(C3), and CoCl2[3-NC5H4CONHPO(NC4H10)2]2(C4) were designed and synthesized. FT-IR, UV-Vis, Atomic Absorption (AAS),1H, 13C, and 31PNMR, and Mass spectroscopies beside CHN and Molar conductivity methods were utilized to characterize the synthesized compounds. Using MTT-assay and Flow Cytometry, the anticancer effects of these complexes were studied on three distinct cell lines, including one normal cell line (MCF10A) and two cancer cell lines (MDA-MB-231, MCF-7). Results showed that our ligands could form complexes by coordinating with cobalt, which, not only have a very strong killing effect on cancer cells but also have a higher level of safety for normal cells and are more cost-efficient than Cisplatin. C3 was the most effective complex at inhibiting the growth of MCF-7 and MDA-MB-231 cells which exhibited a remarkable 97.5 % reduction in cancer cell growth and a Selectivity Index up to > 37. This is an impressive 93 and 54 times more selective and safer than commonly used drugs like Cisplatin and Doxorubicin, respectively.Flow Cytometry analysis shows complex-induced breast cancer cell apoptosis.The ligands' amine structure and ring size can directly impact the complexes' anticancer effect and safety for normal cells.

Targeting prolidase. A survey of the literature data to depict a structure-activity relationship frame and to address future studies for drug development

Prolidase (EC.3.4.13.9) is a Mn+2-dependent dipeptidase that is well known to play a crucial role in several physiological and pathological processes affecting humans. More in particular, this enzyme is involved in the cleavage of proline- and hydroxyproline-containing dipeptides (imidodipeptides), providing a fine regulation of the homeostasis of these two amino acids. Hyperactivity or deficiency of prolidase have been clearly associated to the development and progress of several acute and chronic syndromes (e.g. chronic liver fibrosis, viral and acute hepatitis, cancer, neurological disorders, inflammation, skin diseases, intellectual disability, respiratory infection). Thus, targeting prolidase and modulating its activity is an intriguing field of research with a great therapeutic potential for the next future and for the design of specific and selective drugs. Prolidase can be exploited in two essential ways: as an activator of proline containing prodrugs and by direct interaction. In this latter case, few specific ligands for the title enzyme have been described, but with no reports about their structure-activity relationship. The aim of this comprehensive review is to gather all available information on prolidase targeting so far reported in the literature, to rationalize the observed data and effect into a preliminary structure-relationship picture, to comment about the effectiveness of each reported ligands, and to address future research activities providing new potential and putative natural, semisynthetic, and purely synthetic molecules able to trigger prolidase as the main biological target.

Efficient delivery of methotrexate to MDA-MB-231 breast cancer cells by a pH-responsive ZnO nanocarrier

Methotrexate (MTX), an efficient chemotherapy medication is used in treating various malignancies. However, the breast cancer cell line MDA-MB-231 has developed resistance to it due to low levels of the MTX transport protein, and reduced folate carrier (RFC), making it less effective against these cancer cells. Here we designed a very simple, biocompatible, and non-toxic amine-capped ZnO quantum dots to overcome the MTX resistance on the MDA-MB-231 breast cancer cell line. The QD was characterized by HRTEM, DLS EDX, FT-IR, UV-Vis, and Fluorescence spectroscopy. MTX loading onto the QD was confirmed through fluorescence and UV-Vis spectroscopy. Additionally, extensive confocal microscopic investigations were carried out to determine whether the MTX was successfully released on the MDA-MB-231 cell line. It was discovered that QD is a better pH-responsive delivery system than the previous ones because it successfully delivers MTX to the MDA-MB-231 at a higher rate on an acidic pH than it does at a physiological pH. QD also has anticancer activity and can eradicate cancer cells on its own. These factors make the QD to be an effective pH-responsive delivery system that can improve the efficacy of the medication in therapeutic diagnosis.

Insights about the ability of folate based supramolecular gels to act as targeted therapeutic agents

With the aim to obtain targeted chemotherapeutic agents, imidazolium and ammonium-based folate salts were synthesized. Their photophysical behavior was investigated both in buffer and buffer/DMSO solution as well as in solid phase, performing UV-vis and fluorescence investigations. Properties of the aggregates were also analyzed by dynamic light scattering. Gelation ability of the salts was analyzed in biocompatible solvents, and gel phases obtained were characterized by determining critical gelation concentrations and gel-solution transition temperatures. Insights about gelator interactions in the tridimensional network were also gained performing ATR-FTIR investigation. Properties of soft materials were further analyzed performing rheology measurements, scanning electron microscopy, fluorescence and resonance light scattering investigations. Antiproliferative activity of organic salts was tested towards two breast cancer cell lines, expressing different levels of folate receptor, namely MDA-MB-231 and MCF-7, and a normal epithelial cell line, like h-TER T-RPE-1, by using MTT assay. Dichlodihydrofluorescein acetate test was performed to verify the role of oxidative stress in cell death. Finally, antiproliferative activity was also evaluated in gel phase, to verify if salts were able to retain biological activity also after the entrapment in the gelatinous network. Results collected evidence that folate based organic salts were able to behave as targeted chemotherapeutic agents both in solution and gel phase, showing uptake mechanism and selectivity indexes that depend on both cancer cell line nature and salt structure.

Cluster of resistance-inducing genes in MCF-7 cells by estrogen, insulin, methotrexate and tamoxifen extracted via NMF

Breast cancer has become a leading cause of death for women as the economy has grown and the number of women in the labor force has increased. Several biomarkers with diagnostic, prognostic, and therapeutic implications for breast cancer have been identified in studies, leading to therapeutic advances. Resistance, on the other hand, is one of clinical practice's limitations. In this paper, we use Nonnegative Matrix Factorization to automatically extract two gene signatures from gene expression profiles of wild-type and resistance MCF-7 cells, which were then investigated further using pathways analysis and proved useful in relating resistance pathways to breast cancer regardless of the stimulus that caused it. A few extracted genes (including MAOA, IL4I1, RRM2, DUT, NME4, and SUMO3) represent new elements in the functional network for resistance in MCF-7 ER+ breast cancer. As a result of this research, a better understanding of how resistance occurs or the pathways that contribute to it may allow more effective therapies to be developed.

Delivery of Small Molecules by Syndiotactic Peptides for Breast Cancer Therapy

The utilization of peptide-based drug delivery systems has been suboptimal due to their poor proteolytic susceptibility, poor cell permeability, and limited tumor homing capabilities. Earlier attempts in using d-enantiomers in peptide sequences increased proteolytic stability but have compromised the overall penetration capability. We designed a series of peptides (STRAPs) with a syndiotactic polypeptide backbone that can potentially form a spatial array of cationic groups, an important feature that facilitates cellular uptake. The peptides penetrate cell membranes through a combination of active and passive modes. Furthermore, the cellular uptake of the peptides was unaffected by the presence of or treatment with bovine serum and human plasma. The designed peptides successfully delivered methotrexate, an anticancer drug, to the in vitro and in vivo models of breast cancer, with the best performing peptide STRAP-4-MTX conjugate having an EC50 value of 1.34 μM. Peptide drug delivery in mouse xenograft models showed a greater reduction of primary tumor and metastasis of breast cancer, in comparison to methotrexate of the same dose. The in vivo biodistribution assay of the STRAP-4 peptide suggests that the peptide accumulates at the tumor site after 2 h of treatment, and in the absence of tumors, the peptide gets metabolized and excreted from the system.

Enhanced antitumor activity of combined methotrexate and histone deacetylase inhibitor valproic acid on mammary cancer in vitro and in vivo

Histone deacetylase inhibitors (HDACIs) act as antiproliferative agents by promoting differentiation and inducing apoptosis. Valproic acid (VPA) is an HDACI that shows promising chemotherapeutic effect in several tumor cells. The present study aimed to investigate the inhibitory effect of VPA on the viability of mammary cancer cells and its enhancing effect with methotrexate (MTX) in vitro and in vivo. Treatment with VPA or MTX alone induced concentration-dependent cytotoxic effects in two breast cancer cell lines. VPA significantly increased the cytotoxicity of MTX 3 times against MCF7. VPA addition to MTX, however, did not produce any significant changes on MTX cytotoxicity against MDA-MB231. VPA (150 and 200 mg/kg) significantly inhibited the growth of IP and SC Ehrlich ascites carcinoma tumor mouse models and improved results were achieved for tumor inhibition when VPA was combined with MTX (1 and 2 mg/kg) in vivo. The antitumor activity was not associated with a significant increase in toxicity or mice mortality rate. All these findings suggest that the combination of MTX and VPA may have clinical and/or adjuvant therapeutic application in the treatment of mammary cancer.

Fabrication of methotrexate-loaded gold nanoconjugates and its enhanced anticancer activity in breast cancer

Methotrexate (MTX) is known antagonist of folic acid and widely used as an anti-cancer drug. The folate receptor (FR) and reduced folate carrier are mostly responsible for internalization of methotrexate in tumor cells. Mutation in reduced folate carrier (RFC) leads to resistance against MTX in various tumor cell lines including MDA-MB-231 breast cancer cells. To overcome the resistance of MTX, folate receptor targeted nanoparticles have been commonly used for targeting breast tumors. The aim of the study is to determine the ability of methotrexate gold nanoparticles (MTX-GNPs) in the induction of apoptosis and to explore the molecular changes at genomics and proteomics level. Different assays like cell viability assay, cell cycle analysis, apoptosis, real-time PCR and western blot were carried out to evaluate the anti-cancer effect of MTX-Gold NPs on MCF-7 and MDA-MB-231 cells. Our observations demonstrated the decrease in the percent viable cells after the treatment of MTX-GNPs, with an arrest in cell cycle at G0/G1 phase and a significant increase in apoptotic cell population and loss of mitochondrial membrane potential in MCF-7 and MDA-MB-231 cells. Folate receptor targeted MTX-GNPs showed significant cellular uptake in breast cancer cells along with significant down-regulation in expression of anti-apoptotic gene (Bcl-2) and up-regulation in expression of pro-apoptotic genes (Bax, Caspase-3, Caspase-9, APAF-1, p53). These results unveil the increased anti-cancer effect of MTX-GNPs in cancer cells.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02718-7.

(-)-Kusunokinin inhibits breast cancer in N-nitrosomethylurea-induced mammary tumor rats

Natural and synthetic (-)-kusunokinin inhibited breast cancer, colon cancer and cholangiocarcinoma cells at the G2/M phase and induced apoptosis. However, there is no report on the action and adverse effects of (-)-kusunokinin in animal models. In this study, we investigated the cytotoxic effect of (-)-kusunokinin from Piper nigrum on cancer cells. NMU-induced rat mammary tumors, an ER positive breast cancer model, were treated with (-)-kusunokinin. Proteins of interest related to cell cycle, angiogenesis, migration and signaling proteins were detected in tumor tissues. Results showed that (-)-kusunokinin exhibited strong cytotoxicity against breast, colon and lung cancer cells and caused low toxicity against normal fibroblast cells. For in vivo study, 7.0 mg/kg and 14.0 mg/kg of (-)-kusunokinin reduced tumor growth without side effects on body weight, internal organs and bone marrow. Combination of (-)-kusunokinin with a low effective dose of doxorubicin significantly inhibited tumor growth and provoked cell death in cancer tissues. Mechanistically, 14.0 mg/kg of (-)-kusunokinin decreased cell proliferation (c-Src, PI3K, Akt, p-Erk1/2 and c-Myc), cell cycle (E2f-1, cyclin B1 and CDK1), and metastasis (E-cadherin, MMP-2 and MMP-9) proteins in tumor tissues, which supports its anticancer effect. We further confirmed the antimigration effect of (-)-kusunokinin; the results show that this compound inhibited breast cancer cell (MCF-7) migration in a dose-dependent manner. In conclusion, the results suggest that 14 mg/kg of (-)-kusunokinin inhibited tumors through the reduction of signaling proteins and their downstream molecules. Therefore, (-)-kusunokinin becomes an intriguing candidate for cancer treatment as it provides a strong potency in cancer inhibition.

PTS micelles for the delivery of hydrophobic methotrexate

Polyoxyethanyl-α-tocopheryl sebacate (PTS) is an amphiphilic compound with self-emulsifying properties known to form micelles. In this work, we report the production of PTS micelles for the encapsulation and delivery of a hydrophobic derivative of methotrexate, MTX di-ethylated (MTX-OEt). We optimized the micelles production by testing two different techniques: auxiliary solvent and sonication. Small and homogeneous micelles (≈40 nm) were obtained through the auxiliary solvent method performed at 30 °C and using 15 mg/mL of PTS. The produced micelles with the most promising physicochemical properties did not induce cytotoxicity when tested in normal human cells (BJ5ta cells), being considered for the encapsulation of MTX-OEt. This prodrug was achieved by Fisher esterification using ethanol, being isolated in good yield (η = 68%). MTX-OEt was efficiently encapsulated onto the produced micelles which preserved their physicochemical properties. The PTS micelles loaded with MTX-OEt, free MTX-OEt and free unmodified MTX revealed similar biological effect against cancer cells (Caco-2 cells). These results demonstrated that the biological activity of MTX is not altered after modification. The developed PTS micelles revealed a promising intracellular delivery performance with potentiality for cancer therapy.

Cytotoxicity of eupatorin in MCF-7 and MDA-MB-231 human breast cancer cells via cell cycle arrest, anti-angiogenesis and induction of apoptosis

Eupatorin has been reported with in vitro cytotoxic effect on several human cancer cells. However, reports on the mode of action and detail mechanism of eupatorin in vitro in breast cancer disease are limited. Hence, eupatorin's effect on the human breast carcinoma cell line MCF-7 and MDA-MB-231 was investigated. MTT assay showed that eupatorin had cytotoxic effects on MCF-7 and MDA-MB-231 cells but was non-toxic to the normal cells of MCF-10a in a time-dose dependent manner. At 24 h, the eupatorin showed mild cytotoxicity on both MCF-7 and MDA-MB-231 cells with IC50 values higher than 20 μg/mL. After 48 h, eupatorin at 5 μg/mL inhibited the proliferation of MCF-7 and MDA-MB-231 cells by 50% while the IC50 of MCF-10a was significantly (p < 0.05) high with 30 μg/mL. The concentration of eupatorin at 5 μg/mL induced apoptosis mainly through intrinsic pathway by facilitating higher fold of caspase 9 compared to caspase 8 at 48 h. The cell cycle profile also showed that eupatorin (5 μg/mL) exerted anti-proliferation activity with the cell cycle arrest of MCF-7 and MDA-MB-231 cells at sub Gθ/G1 in a time-dependent manner. In addition, wound healing assay showed an incomplete wound closure of scratched MDA-MB-231 cells, and more than 60% of the MDA-MB-231 cells were prevented to migrate and invade the membrane in the Boyden chamber after 24 h. Eupatorin also inhibited angiogenic sprouting of new blood vessels in ex vivo mouse aorta ring assay. In gene expression assay, eupatorin up-regulated pro-apoptotic genes such as Bak1, HIF1A, Bax, Bad, cytochrome c and SMAC/Diablo and blocked the Phospho-Akt pathway. In conclusion, eupatorin is a potent candidate to induce apoptosis and concurrently inhibit the invasion, migration and angiogenesis of MDA-MB-231 and MCF-7 cells through inhibition of Phospho-Akt pathway and cell cycle blockade.

Ultrasound-assisted biosynthesis of novel methotrexate-conjugates

New methotrexate-acylglycerols and methotrexate-cyclodextrins (α, β and γ-CD) conjugates were obtained via esterification or transesterification reactions. All reactions were catalysed by esterases namely immobilized Lipase from Candida antarctica B and Lipase from Thermomyces lanuginosus. The use of ultrasound to assist the reactions revealed to be a key factor to obtain high conversion yields on both MTX conjugates. Transesterification reactions including long chain triacylglycerols were only successful when ultrasound was applied. In cyclodextrins esterification a higher number of MTX molecules was also linked to cyclodextrins when ultrasound was used. All the conjugates were characterized by MALDI-TOF and NMR spectroscopy.

Amino Acids in the Development of Prodrugs

Although drugs currently used for the various types of diseases (e.g., antiparasitic, antiviral, antibacterial, etc.) are effective, they present several undesirable pharmacological and pharmaceutical properties. Most of the drugs have low bioavailability, lack of sensitivity, and do not target only the damaged cells, thus also affecting normal cells. Moreover, there is the risk of developing resistance against drugs upon chronic treatment. Consequently, their potential clinical applications might be limited and therefore, it is mandatory to find strategies that improve those properties of therapeutic agents. The development of prodrugs using amino acids as moieties has resulted in improvements in several properties, namely increased bioavailability, decreased toxicity of the parent drug, accurate delivery to target tissues or organs, and prevention of fast metabolism. Herein, we provide an overview of models currently in use of prodrug design with amino acids. Furthermore, we review the challenges related to the permeability of poorly absorbed drugs and transport and deliver on target organs.

Design, synthesis of methotrexate-diosgenin conjugates and biological evaluation of their effect on methotrexate transport-resistant cells

A series of methotrexate-diosgenin conjugates was designed and synthesized to enhance the passive internalization of methotrexate (MTX) into transport-resistant cells. The inhibitory effects of these conjugates on dihydrofolate reductase (DHFR), and their anti-proliferation behaviors against a transport-resistant breast cancer cell line, MDA-MB-231, were investigated. All of the synthesized conjugates retained an ability to inhibit DHFR after the diosgenin substitution. The MTX conjugates were much more potent against methotrexate-resistant MDA-MB-231 cells than MTX. Conjugate 18, containing a disulfide bond, exhibited the most potent anti-proliferative and DHFR inhibitory effects (IC₅₀=4.1μM and 17.21nM, respectively). Anti-proliferative activity was higher in the conjugate with a longer space linker (conjugate 21) than those with shorter linkers (conjugates 19 and 20). These results suggest that diosgenin conjugation of MTX may be an effective way to overcome its transport resistance in cancer cells.

Methotrexate-grafted-oligochitosan micelles as drug carriers: synthesis and biological evaluations

The novel amphiphilic derivatives of Methotrexate-chitosan oligosaccharide (MTX-CHO) with different molar feeding ratios of MTX were synthesized. The degree of MTX substitution ranged from 4.47 to 13.5%. MTX-CHO copolymer formed micelles with an average size of 134.6±14.52 to 236.6±30.01 nm, and zeta potential of 20±5 to 16.8±7.74 mV. The critical micelle concentration was found to range from 125 to 0.56 mg/l. Analysis of micelles with different degree of substitutions (DSs) revealed that the size of micelles decreased by increasing DS while zeta potential was reduced. Release study indicated that drug content had effect on the release rate. With increasing amount of loaded drug in the micelle, release rate was decreased. Drug loaded and unloaded MTX-CHO micelles showed significant cytotoxicity on MDA-MB-231. Loaded micelle was more effective than unloaded one which indicated that conjugation could reduce efficacy of MTX. The viability of MDA-MB-231 in presence of drug loaded micelles was significantly decreased and cell viability at 1 µg/ml was 45.17±9% while the viability of unloaded micelles was 91.86±9.88. These phenomena make MTX-CHO micelles as a good candidate for hydrophobic anticancer drug carrier.

Synergistic antiproliferative effects of methotrexate-loaded smart silica nanocomposites in MDA-MB-231 breast cancer cells

In this study, the ability of methotrexate (MTX)-loaded stimuli-responsive novel silica nanocomposites (MSNs) (with mean diameter of ± 60 nm) in the induction of apoptosis, and change in the Bax/Bcl-2 mRNA levels, were investigated. MTT assay and RT -PCR analysis were performed on MDA-MB-231 breast cancer cells, to evaluate their anti-proliferative, apoptotic and anti-apoptotic effects. MTX-loaded MSNs caused marked decrease in the percentage of viable cells, with a significant down-regulation in the level of expression of the anti-apoptotic gene (Bcl-2), and up-regulation in the apoptotic gene (Bax). MTX-loaded MSNs increased the efficacy of the chemotherapeutic agents in the inhibition of cell proliferation and induction of apoptosis.

A novel melphalan polymeric prodrug: preparation and property study

The clinical application of melphalan (Me), an anticancer drug for the treatment of hematologic malignancies, has been limited due to its poor water solubility, rapid elimination and lack of target specificity. To solve these problems, O,N-carboxymethyl chitosan-peptide-melphalan conjugates were synthesized and characterized. All polymeric prodrugs showed satisfactory water solubility. It was found that the molecular weight of O,N-carboxymethyl chitosan (O,N-CMCS) and the peptide spacer played a crucial role in controlling the drug content, diameter and drug release properties of O,N-carboxymethyl chitosan-peptide-melphalan conjugates. The studies of in vitro drug release and cell cytotoxicity by MTT assay revealed that, employing the polymeric conjugation strategy and using the peptides glycylglycine (Gly-Gly) as a spacer, the conjugates have good cathepsin X-sensitivity and lower toxicity and the drug release behavior improved remarkably. In conclusion, O,N-carboxymethyl chitosan-peptide-melphalan conjugates could be promising prodrugs for anticancer application.

Amino acids as promoieties in prodrug design and development

Prodrugs are biologically inactive agents that upon biotransformation in vivo result in active drug molecules. Since prodrugs might alter the tissue distribution, efficacy and the toxicity of the parent drug, prodrug design should be considered at the early stages of preclinical development. In this regard, natural and synthetic amino acids offer wide structural diversity and physicochemical properties. This review covers the use of amino acid prodrugs to improve poor solubility, poor permeability, sustained release, intravenous delivery, drug targeting, and metabolic stability of the parent drug. In addition, practical considerations and challenges associated with the development of amino acid prodrugs are also covered.

A review of therapeutic challenges and achievements of methotrexate delivery systems for treatment of cancer and rheumatoid arthritis

PURPOSE

Methotrexate (MTX) is one of the most widely studied and effective therapeutics agents available to treat many solid tumors, hematologic malignancies, and autoimmune diseases such as rheumatoid arthritis; however, the poor pharmacokinetic and narrow safety margin of the drug limits the therapeutic outcomes of conventional drug delivery systems. For an improved delivery of MTX, several pathophysiological features such as angiogenesis, enhanced permeability and retention effects, acidosis, and expression of specific antigens and receptors can be used either as targets or as tools for drug delivery.

METHODS

There are many novel delivery systems developed to improve the pitfalls of MTX therapy ranged from polymeric conjugates such as human serum albumin, liposomes, microspheres, solid lipid nanoparticles, polymeric nanoparticles, dendrimers, polymeric micelles, in situ forming hydrogels, carrier erythrocyte, and nanotechnology-based vehicles such as carbon nanotubes, magnetic nanoparticles, and gold nanoparticles. Some are further modified with targeting ligands for active targeting purposes.

RESULTS

Such delivery systems provide prolonged plasma profile, enhanced and specific activity in vitro and in vivo in animal models. Nevertheless, more complementary studies are needed before they can be applied in human.

CONCLUSION

This review deals with the challenges of conventional systems and achievements of each pharmaceutical class of novel drug delivery vehicle.

Improved prolidase activity assay allowed enzyme kinetic characterization and faster prolidase deficiency diagnosis

BACKGROUND

Prolidase is a metallo-exopeptidase hydrolyzing X-Pro and X-Hyp dipeptides. Its absence or reduced level is typical in prolidase deficiency (PD) patients, and altered prolidase activity was reported in various diseases. Therefore, standardized and accurate measurement of prolidase activity is essential for PD diagnosis, as well as to elucidate the pathophysiology of other disorders.

METHODS

Human recombinant prolidase was used to optimize a spectrophotometric enzyme activity assay. Kinetic parameters and Mn(2+) affinity were evaluated. The method was validated on blood and fibroblasts from PD patients.

RESULTS

An activation step consisting in prolidase incubation with 1 mmol/l MnCl(2) and 0.75 mmol/l reduced glutathione at 50°C for 20 min was necessary to obtain the maximum activity and to accurately determine, for the recombinant enzyme, V(max) (489 U/mg), K(m) (5.4 mM) and Mn(2+) affinity (54 mM(-1)). The method applied to PD diagnosis revealed an intra-assay CV=8% for blood and 9% for fibroblasts lysates. The inter-assay CV was 21% for blood and 20% for cell lysates.

CONCLUSION

We optimized a faster spectrophotometric method to measure the activity when the enzyme is fully activated, this is crucial to allow a reliable evaluation of prolidase activity from different sources.