Photodynamic therapy (PDT) of cancer uses photosensitizers (PS), a light source and oxygen to generate high levels of reactive oxygen species (ROS), that exert a cytotoxic action on tumor cells. ...Recently, it has been shown that mixed non-symmetrical diaryl porphyrins, with two different pendants, are more photodynamically active than symmetrical diaryl porphyrins.
In the present study, we investigate the in vitro photodynamic effects of four novel non-symmetrical diaryl porphyrins, two of which bear one pentafluoro-phenyl and one bromo-alkyl (apolar) pendant, whereas the two others bear one pentafluoro-phenyl and one cationic pyridine pendant. The four compounds were tested in a small panel of human cancer cell lines, and their photodynamic activities were compared with that of m-THPC (Foscan), currently the most successful PS approved for clinical use in cancer PDT.
The results of the cytotoxicity studies indicate that the two molecules bearing the cationic pendant are more potent in vitro than those with the apolar pendant, and that they are as potent as Foscan. To gain further insights into the mechanism of PS-induced phototoxicity, induction of apoptotic, autophagic and necrotic cell death, and generation of reactive oxygen species (ROS) were evaluated in cancer cells following exposure to the PSs and irradiation. The effect of the PSs on the migratory activity of the cells was also assessed.
The data obtained from this work support a greater potency of diaryl porphyrins with a positive charge in inducing cell death, as compared to those with the bromo-alkyl pendant; most importantly, some of these novel compounds exhibit features that might make them superior to the clinically approved PS Foscan.
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•Four novel non-symmetrical diaryl porphyrins, two of which bear one cationic pyridine pendant, were synthesized.•Upon photoactivation, the cationic compounds are more potent than the apolar ones in inhibiting cancer cell proliferation.•All compounds inhibit cell migration, a feature that is not observed with Foscan, so far the most successful agent in PDT.
Temozolomide (TMZ) is a methylating agent with promising antitumor efficacy for the treatment of melanomas and intermediate-grade gliomas. Unfortunately, its use in the management of high-grade ...gliomas (glioblastomas) is limited by multifaceted resistance mechanisms. The aim of this study was to evaluate the possibility to improve the cytotoxic response of two human glioblastoma cell lines, U87MG and U373MG, to TMZ by the use of Tempol (TPL), a low molecular weight piperidine nitroxide that has been shown to inhibit in vitro and in vivo growth of murine glioma cells. To this purpose, we used two different schedules for the combined exposure to the two agents. Our data indicate that TPL synergizes with TMZ in both U87MG and U373MG cells for both schedules tested. This effect is accompanied by an increase in apoptotic cell death and by changes in the expression of genes involved in control of the apoptotic process. TPL was also observed to induce a cell-type specific decrease in GSH levels and in GSH-related enzyme activities that could contribute to its sensitizing effect.
To date, there are no approved treatments for the diminished strength and paralysis that result from the loss of peripheral nerve function due to trauma, heritable neuromuscular diseases, or aging. ...Here, we showed that denervation resulting from transection of the sciatic nerve triggered a marked increase in the prostaglandin-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in skeletal muscle in mice, providing evidence that injury drives early expression of this aging-associated enzyme or gerozyme. Treating mice with a small-molecule inhibitor of 15-PGDH promoted regeneration of motor axons and formation of neuromuscular synapses leading to an acceleration in recovery of force after an acute nerve crush injury. In aged mice with chronic denervation of muscles, treatment with the 15-PGDH inhibitor increased motor neuron viability and restored neuromuscular junctions and function. These presynaptic changes synergized with previously reported muscle tissue remodeling to result in a marked increase in the strength of aged muscles. We further found that 15-PGDH aggregates defined the target fibers that are histopathologic hallmarks of human neurogenic myopathies, suggesting that the gerozyme may be involved in their etiology. Our data suggest that inhibition of 15-PGDH may constitute a therapeutic strategy to physiologically boost prostaglandin E2, restore neuromuscular connectivity, and promote recovery of strength after acute or chronic denervation due to injury, disease, or aging.
Multi-action cisplatin-based mono- (1) and di-clofibric acid (2) Pt(iv) "combo" derivatives were synthesized via both traditional and microwave assisted procedures. The two complexes offered very ...good performances (IC50 values in a nanomolar range) on a panel of human tumor cell lines, including the highly chemoresistant malignant pleural mesothelioma ones. Moreover, both 1 and 2 bypass the cisplatin resistance. Indeed, cisplatin and clofibric acid, the metabolites of the Pt(iv) → Pt(ii) intracellular reduction, proved to act synergistically. The adjuvant action of clofibric acid relies on the activation of peroxisome proliferator-activated receptor α (PPARα) that, in turn, decreases the level of Hypoxia-Inducible Factor-1α. Both compounds induced extensive apoptosis in tumor cells, also via oxidative stress. Finally, 2 exhibited excellent performances also under the hypoxic conditions typical of solid tumors, where cisplatin is less effective.
Electrophysiological alterations of the neuromuscular junction (NMJ) and motor unit potential (MUP) with unloading are poorly studied. We aimed to investigate these aspects and the underlying ...molecular mechanisms with short‐term unloading and active recovery (AR). Eleven healthy males underwent a 10‐day unilateral lower limb suspension (ULLS) period, followed by 21‐day AR based on resistance exercise. Quadriceps femoris (QF) cross‐sectional area (CSA) and isometric maximum voluntary contraction (MVC) were evaluated. Intramuscular electromyographic recordings were obtained during 10% and 25% MVC isometric contractions from the vastus lateralis (VL). Biomarkers of NMJ molecular instability (serum c‐terminal agrin fragment, CAF), axonal damage (neurofilament light chain) and denervation status were assessed from blood samples and VL biopsies. NMJ and ion channel transcriptomic profiles were investigated by RNA‐sequencing. QF CSA and MVC decreased with ULLS. Increased CAF and altered NMJ transcriptome with unloading suggested the emergence of NMJ molecular instability, which was not associated with impaired NMJ transmission stability. Instead, increased MUP complexity and decreased motor unit firing rates were found after ULLS. Downregulation of ion channel gene expression was found together with increased neurofilament light chain concentration and partial denervation. The AR period restored most of these neuromuscular alterations. In conclusion, the human NMJ is destabilized at the molecular level but shows functional resilience to a 10‐day unloading period at least at relatively low contraction intensities. However, MUP properties are altered by ULLS, possibly due to alterations in ion channel dynamics and initial axonal damage and denervation. These changes are fully reversed by 21 days of AR.
Key points
We used integrative electrophysiological and molecular approaches to comprehensively investigate changes in neuromuscular integrity and function after a 10‐day unilateral lower limb suspension (ULLS), followed by 21 days of active recovery in young healthy men, with a particular focus on neuromuscular junction (NMJ) and motor unit potential (MUP) properties alterations.
After 10‐day ULLS, we found significant NMJ molecular alterations in the absence of NMJ transmission stability impairment. These findings suggest that the human NMJ is functionally resilient against insults and stresses induced by short‐term disuse at least at relatively low contraction intensities, at which low‐threshold, slow‐type motor units are recruited.
Intramuscular electromyography analysis revealed that unloading caused increased MUP complexity and decreased motor unit firing rates, and these alterations could be related to the observed changes in skeletal muscle ion channel pool and initial and partial signs of fibre denervation and axonal damage.
The active recovery period restored these neuromuscular changes.
figure legend
Eleven young males took part in a 10‐day unilateral lower limb suspension (ULLS) intervention. This unloading period was followed by 21 days of subsequent active recovery (AR) based on resistance exercise. At baseline, after ULLS and after AR we evaluated muscle size by ultrasound and in vivo muscle function by isometric dynamometry. Motor unit potential (MUP) properties and neuromuscular junction (NMJ) transmission stability were assessed using intramuscular electromyography. Finally, vastus lateralis muscle biopsies and blood samples were collected. The ULLS intervention resulted in increased NMJ molecular instability in absence of NMJ transmission stability impairment. Changes in MUP properties were observed, including increased MUP complexity and decreased motor unit firing rates, possibly due to initial axonal damage, partial denervation and altered ion channels dynamics. The AR period was effective in restoring these neuromuscular changes. LS0: baseline data collection; LS10: unilateral lower limb suspension day 10; AR21: active recovery day 21.
Abstract only
Introduction
Disuse atrophy may not only arise from a reduction in mechanical loading but also from muscle denervation and neuromuscular junction damage, triggered by inactivity
1
,
2
. ...The identification of biomarkers of muscle atrophy and of neuromuscular degeneration is therefore needed for an early detection of neuromuscular alterations induced by inactivity. The aim of this study was to investigate the onset of muscle atrophy and of neuromuscular alterations during a short‐term inactivity period.
Methods
Ten healthy males (aged 23±5 years) participated to a 10‐day bed rest (BR) study, after Ethical approval and informed consent. Blood samples were collected every two days for the assessment of NMJ damage from serum levels of c‐terminal agrin fragment (CAF). Muscle fibre denervation was determined from the expression of neural cell adhesive molecule (N‐CAM) in myofibres obtained from vastus lateralis (VL) muscle biopsies at baseline, 5 and 10 days of BR. Myofibre atrophy was assessed from mean fibre cross‐sectional area (CSA). Whole muscle atrophy was assessed from measurements of muscle architecture (pennation angle and muscle CSA) every two days of BR using ultrasonography. Significance of differences was tested with repeated‐measures Anova, level of significance was set at p<0.05.
Results
Atrophy of whole muscle and of myofibers, represented by decreases of 5.8% in muscle CSA (P<0.0001), 7.3% in pennation angle (P<0.0001), and by a 21% reduction in mean fibre CSA (P<0.01) were detected after 10 days of BR. A 19% increase (p<0.01) in CAF levels was found on BR day 10, together with a 18‐fold increase in N‐CAM positive myofibres. The analysis of myofiber CSA and N‐CAM expression at BR 5 day is in progress.
Conclusions
These findings show a very early onset (within 10 days) of whole muscle and fiber atrophy accompanied by NMJ damage and myofiber denervation in response to chronic inactivity. We suggest that countermeasures against neuromuscular maladaptation to chronic inactivity ought to be implemented as early as possible.
Support or Funding Information
Funding by
ASI, MARS‐PRE Project, n. DC‐VUM‐2017‐006
, is acknowledged.
Purpose
The partitioning of the electromechanical delay by an electromyographic (EMG), mechanomyographic (MMG) and force combined approach can provide further insight into the electrochemical and ...mechanical processes involved with skeletal muscle contraction and relaxation. The aim of the study was to monitor by this combined approach the changes in delays’ electrochemical and mechanical components throughout a fatiguing task and during recovery in patients with myotonic dystrophy type 1 (DM1), who present at the skeletal muscle level fibres rearrangement, muscle weakness and myotonia, especially in the distal muscles.
Methods
After assessing maximum voluntary contraction (MVC), 14 male patients with DM1 and 14 healthy controls (HC) performed a fatiguing exercise at 50% MVC until exhaustion. EMG, MMG, and force signals were recorded from tibialis anterior and vastus lateralis muscles. The electromechanical delay during contraction (Delay
TOT
) and relaxation (R-Delay
TOT
) components, EMG and MMG root mean square (RMS) and mean frequency (MF) were calculated off-line.
Results
The fatiguing exercise duration was similar in both groups. In patients with DM1, delays components were significantly longer compared to HC, especially in the distal muscle during relaxation. Delays components recovered quickly from the fatiguing exercise in HC than in patients with DM1 in both muscles.
Conclusions
The alterations in delays observed in DM1 during the fatiguing exercise may indicate that also the lengthening of the electrochemical and mechanical processes during contraction and relaxation could play a role in explaining exercise intolerance in this pathology.
The antitumor activity of ruthenium(II) arene (p-cymene, benzene, hexamethylbenzene) derivatives containing modified curcumin ligands ...(HCurcI=(1E,4Z,6E)-5-hydroxy-1,7-bis(3,4-dimethoxyphenyl)hepta-1,4,6-trien-3-one and HCurcII=(1E,4Z,6E)-5-hydroxy-1,7-bis(4-methoxyphenyl)hepta-1,4,6-trien-3-one) is described. These have been characterized by IR, ESI-MS and NMR spectroscopy. The X-ray crystal structure of HCurcI has been determined and compared with its related Ru complex. Four complexes have been evaluated against five tumor cell lines, whose best activities IC50 (μM) are: breast MCF7, 9.7; ovarian A2780, 9.4; glioblastoma U-87, 9.4; lung carcinoma A549, 13.7 and colon-rectal HCT116, 15.5; they are associated with apoptotic features. These activities are improved when compared to the already known corresponding curcumin complex, (p-cymene)Ru(curcuminato)Cl, about twice for the breast and ovarian cancer, 4.7 times stronger in the lung cancer and about 6.6 times stronger in the glioblastoma cell lines. In fact, the less active (p-cymene)Ru(curcuminato)Cl complex only shows similar activity to two novel complexes in the colon cancer cell line. Comparing antitumor activity between these novel complexes and their related curcuminoids, improvement of antiproliferative activity is seen for a complex containing CurcII in A2780, A549 and U87 cell lines, whose IC50 are halved. Therefore, after replacing OH curcumin groups with OCH3, the obtained species HCurcI and its Ru complexes have increased antitumor activity compared to curcumin and its related complex. In contrast, HCurcII is less cytotoxic than curcumin but its related complex (p-cymene)Ru(CurcII)Cl is twice as active as HCurcII in 3 cell lines. Results from these novel arene-Ru curcuminoid species suggest that their increased cytotoxicity on tumor cells correlate with increase of curcuminoid lipophilicity.
By replacing the two OH groups in curcumin with less polar groups, the antiproliferative activity of related (arene)RuIICl(ligand) increases in four out of five tumor cell lines. Display omitted
•Ru-curcuminoid complexes show increased antiproliferative activity with ligand lipophilicity•Ru-curcuminoid complexes show increased antiproliferative activity with less polar ligands•Our novel curcumin ligands have increased activity compared to Ru-curcumin complexes
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The antiproliferative action of hispolon derivatives is stronger than that of related curcumin against several tumor cell lines. Hispolon size, smaller than curcumin, fits better than ...curcumin into the active site of HDAC6, an enzyme involved in deacetylation of lysine residues. HDACs are considered potential targets for tumor drug discovery and hydroxamates are known inhibitors of HDACs. One of them, SAHA (Vorinostat) is used in clinical studies. Investigations into possible mechanisms for hispolon derivatives active against the HCT116 colon tumor cell line are done after examining the structural results obtained from hispolon X-ray crystal structures as well as performing associated computational docking and Density Functional Theory techniques on HDAC6. These studies show preference for the HDAC6 active site by chelating the Zn center, in contrast with other ineffective hispolon derivatives, that establish only a single bond to the metal center. Structure activity relationships make clear that hydrogenation of the hispolon bridge also leads to single bond (non chelate) hispolon-Zn binding, and consistently nullifies the antiproliferative action against HCT116 tumor.
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