Search

Abstract TNF receptor-associated factors (TRAFs) are signaling adaptor proteins that play a crucial role in regulating cellular receptors’ signaling transduction to downstream pathways and exert multifaceted roles in regulating signaling pathways, cell survival, and carcinogenesis. The 13-cis-retinoic acid (RA), an active metabolite of vitamin A, exhibits anti-cancer properties, but the development of retinoic acid resistance poses a challenge in clinical application. This study aimed to investigate the relationship between TRAFs and retinoic acid sensitivity in various cancers. Here, we revealed that TRAFs’ expression varied significantly across The Cancer Genome Atlas (TCGA) cancer cohorts and human cancer cell lines. Additionally, inhibiting TRAF4, TRAF5, or TRAF6 improved retinoic acid sensitivity and reduced colony formation in ovarian cancer and melanoma cells. Mechanistically, knocking down TRAF4, TRAF5, or TRAF6 in retinoic acid-treated cancer cell lines increased the levels of procaspase 9 and induced cell apoptosis. Further in vivo studies using the SK-OV-3 and MeWo xenograft models confirmed the anti-tumor effects of TRAF knockdown combined with retinoic acid treatment. These findings support that combination therapy with retinoic acid and TRAF silencing may offer significant therapeutic advantages in treating melanoma and ovarian cancers.

Human nucleolin (hNcl) is a multifunctional protein involved in the progression of various cancers and plays a key role in other pathologies. Therefore, there is still unsatisfied demand for hNcl modulators. Recently, we demonstrated that the plant ent-kaurane diterpene oridonin inhibits hNcl but, unfortunately, this compound is quite toxic for healthy cells. Trachylobane diterpene 6,19-dihydroxy-ent-trachiloban-17-oic acid (compound 12) extracted from Psiadia punctulata (DC.) Vatke (Asteraceae) emerged as a ligand of hNcl from a cellular thermal shift assay (CETSA)-based screening of a small library of diterpenes. Effective interaction between this compound and the protein was demonstrated to occur both in vitro and inside two different types of cancer cells. Based on the experimental and computational data, a model of the hNcl/compound 12 complex was built. Because of this binding, hNcl mRNA chaperone activity was significantly reduced, and the level of phosphorylation of the protein was affected. At the biological level, cancer cell incubation with compound 12 produced a cell cycle block in the subG0/G1 phase and induced early apoptosis, whereas no cytotoxicity towards healthy cells was observed. Overall, these results suggested that 6,19-dihydroxy-ent-trachiloban-17-oic could represent a selective antitumoral agent and a promising lead for designing innovative hNcl inhibitors also usable for therapeutic purposes. [ABSTRACT FROM AUTHOR]

• Voltage-gated potassium channels Kv1.3 are widely distributed among tissues. • Channel inhibitors may find application in therapy of some cancers. • Some naturally occurring flavonoids, chalcones and statins inhibit the channels. • The inhibition may be augmented when the compounds are co-applied. • The inhibition may be related to a reduction of cancer cell viability. Voltage-gated potassium channels Kv1.3 are widely expressed in many cell types, both in the plasma membrane and in the inner mitochondrial membrane (mito Kv1.3 channels). An inhibition of the channels may putatively find clinical application in therapy of some cancers characterised by an over-expression of Kv1.3 channels, such as melanoma, pancreatic ductal adenocarcinoma (PDAC), multiple myeloma and B-type chronic lymphocytic leukaemia (B-CLL). An ability to inhibit Kv1.3 channels in cancer cells is shared by some plant-derived polycyclic compounds from the groups of flavonoids, chalcones and statins. The inhibitory effect on the channels may be significantly augmented when the flavonoids and the chalcones are co-applied with the statins: simvastatin and mevastatin. The inhibition of Kv1.3 channels, presumably mito Kv1.3 channels, may be involved in a pro-apoptotic activity of these compounds on Kv1.3 channel-expressing cancer cells. This pro-apoptotic activity may significantly be improved when the selected flavonoids and chalcones are co-applied with the statins. Therefore, these naturally occurring compounds may putatively find clinical application in therapy of above-mentioned cancers, especially when applied in a combination. [Display omitted] [ABSTRACT FROM AUTHOR]

Regular physical activity reduces the risk of several site-specific cancers in humans and suppresses tumour growth in animal models. The mechanisms through which exercise reduces tumour growth remain incompletely understood, but an intriguing and accumulating body of evidence suggests that the incubation of cancer cells with post-exercise serum can have powerful effects on key hallmarks of cancer cell behaviour in vitro. This suggests that exercise can impact tumour biology through direct changes in circulating proteins, RNA molecules and metabolites. Here, we provide a comprehensive narrative overview of what is known about the effects of exercise-conditioned sera on in vitro cancer cell behaviour. In doing so, we consider the key limitations of the current body of literature, both from the perspective of exercise physiology and cancer biology, and we discuss the potential in vivo physiological relevance of these findings. We propose key opportunities for future research in an area that has the potential to identify key anti-oncogenic protein targets and optimise physical activity recommendations for cancer prevention, treatment and survivorship. [ABSTRACT FROM AUTHOR]

Mu-2-related death-inducing gene (MUDENG, MuD) has been reported to be involved in the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-associated apoptotic pathway of glioblastoma multiforme (GBM) cells; however, its expression level, interactors, and role in tumors are yet to be discovered. To investigate whether MuD expression correlates with cancer progression, we analyzed The Cancer Genome Atlas (TCGA) database using UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA). Differential expression of MuD was detected in 6 and 10 cancer types, respectively. Validation performed using data from the Gene Expression Omnibus database showed that MuD expression is downregulated in KIRC tumor and correlate with higher chance of survival. Upregulation of MuD expression in GBM tumors was detected through GEPIA and high MuD expression correlated with higher survival in proneural GBM, whereas the opposite was observed in classical GBM subtype. GBM biospecimens analysis shows that MuD protein level was upregulated in three of six specimens, whereas mRNA level remained relatively unaltered. Therefore, MuD may exert differential effects according to subtypes, and/or be subjected to post-translational regulation in GBM. Correlation analysis between GBM cohort database and experiments using GBM cell lines revealed its positive effect on regulation of protein phosphatase 2 regulatory subunit B’Epsilon (PPP2R5E) and son of sevenless homolog 2 (SOS2). STRING database analysis indicated that the components of adaptor protein complexes putatively interacted with MuD but showed no correlation in terms of survival of patients with different GBM subtypes. In summary, we analyzed the expression of MuD in publicly available cancer patient data sets, GBM cell lines, and biospecimens to demonstrate its potential role as a biomarker for cancer prognosis and identified its candidate interacting molecules.

Mu-2-related death-inducing gene (MUDENG, MuD) has been reported to be involved in the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-associated apoptotic pathway of glioblastoma multiforme (GBM) cells; however, its expression level, interactors, and role in tumors are yet to be discovered. To investigate whether MuD expression correlates with cancer progression, we analyzed The Cancer Genome Atlas (TCGA) database using UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA). Differential expression of MuD was detected in 6 and 10 cancer types, respectively. Validation performed using data from the Gene Expression Omnibus database showed that MuD expression is downregulated in KIRC tumor and correlate with higher chance of survival. Upregulation of MuD expression in GBM tumors was detected through GEPIA and high MuD expression correlated with higher survival in proneural GBM, whereas the opposite was observed in classical GBM subtype. GBM biospecimens analysis shows that MuD protein level was upregulated in three of six specimens, whereas mRNA level remained relatively unaltered. Therefore, MuD may exert differential effects according to subtypes, and/or be subjected to post-translational regulation in GBM. Correlation analysis between GBM cohort database and experiments using GBM cell lines revealed its positive effect on regulation of protein phosphatase 2 regulatory subunit B'Epsilon (PPP2R5E) and son of sevenless homolog 2 (SOS2). STRING database analysis indicated that the components of adaptor protein complexes putatively interacted with MuD but showed no correlation in terms of survival of patients with different GBM subtypes. In summary, we analyzed the expression of MuD in publicly available cancer patient data sets, GBM cell lines, and biospecimens to demonstrate its potential role as a biomarker for cancer prognosis and identified its candidate interacting molecules. [ABSTRACT FROM AUTHOR]

The influence of a prenylated flavonoid-6-prenylnaringenin (6-PR) and selected non-prenylated flavonoids: acacetin, chrysin, baicalein, wogonin, and luteolin on the activity of voltage-gated potassium channels Kv1.3 was investigated in human leukemic Jurkat T cells. Electrophysiological measurements were accompanied by studies on the cytotoxic effect of the examined compounds on Jurkat T cells. Electrophysiological studies were performed using the whole-cell patch-clamp technique. Cell viability was determined using the MTT assay. 6-PR inhibited Kv1.3 channels in Jurkat T cells in a concentration-dependent manner. The estimated value of the half-blocking concentration (EC50) was about 5.76 µM. Among non-prenylated flavonoids, acacetin and chrysin inhibited Kv1.3 channels in Jurkat T cells when applied at the concentration of 30 µM, whereas baicalein, wogonin, and luteolin were ineffective at this concentration. The inhibitory effects of acacetin and chrysin on Kv1.3 channels were significantly less potent than the inhibition caused by 6-PR. All tested compounds inhibited growth of Jurkat T cells in a concentration-dependent manner. Wogonin and chrysin were the most cytotoxic flavonoids tested, whereas baicalein and 6-PR were the least cytotoxic compounds. In accordance to our hypothesis the prenylated flavonoid (6-PR) was much more effective inhibitor of Kv1.3 channels than non-prenylated compounds selected for this study. The inhibition of Kv1.3 channels by 6-PR, acacetin, and chrysin was not related to cytotoxicity of these compounds. The channels' inhibition might be involved in anti-proliferative and pro-apoptotic effects of 6-PR, acacetin and chrysin observed in cancer cell lines expressing these channels. [ABSTRACT FROM AUTHOR]

Background/Aims: Thyroid carcinoma (TC) is a highly lethal malignant cancer and its carcinogenesis remains undetermined. Dysregulation of microRNAs (miRNAs) is well known to be involved in the development of various cancers, including TC, whereas a role of miR-3666 in the pathogenesis of TC has not been appreciated. Methods: We analyzed the levels of MET and miR-3666 in TC tissue and the relationship of miR-3666 levels with patients' prognosis. We then overexpressed miR-3666 by miRNA mimics transfection and inhibited miR-3666 by miRNA antisense transfection in TC cells. Cell survival and growth were analyzed by CCK-8 assay and MTT assay, respectively. Cell apoptosis and proliferation were analyzed by flow cytometry. Bioinformatics analyses were applied to predict miR-3666 targets, which was then confirmed using luciferase reporter assay. Results: We detected significantly higher levels of MET, and significantly lower levels of miR-3666 in TC tissue, compared to the adjacent non-tumor tissue. Moreover, the low miR-3666 levels were associated with poor survival of the patients. Overexpression of miR-3666 significantly inhibited cell growth, while depletion of miR-3666 increased cell growth in TC cells. Moreover, the effects of miR-3666 on cell growth appeared to result from alteration in cell proliferation, rather than changes in cell apoptosis. MiR-3666 was found to bind to the 3'-UTR of MET mRNA to inhibit its translation in TC cells. Conclusion: Reduced miR-3666 levels in TC tissue may promotes TC growth, possibly through MET-mediated cell proliferation.

Lysosomal micropolarity-change is one of the ultimate reflection factors of cell apoptosis and death in complex living organism. Thus, rapid and sensitive detecting of lysosomal micropolarity-change is beneficial for real-time estimating of cancer cell apoptosis. Many polarity-specific fluorescent probes have been reported, but lysosomal micropolarity-ultrasensitive ratiometric fluorescent probe with excellent two-photon property for real-time estimating the cancer cell apoptosis is scarce. In this work, an intramolecular charge transfer (ICT) two-photon ratiometric fluorescent probe ( DC ) was reported and evaluated to real-time estimate cancer cell apoptosis through ultrasensitive detection of lysosomal micro-polarity. DC appeared different fluorescence intensities at 580 and 600 nm in cancer cells, specifically. And its fluorescence change presented a linear change on ratio mode in the range of polarity (Δ f  = 0.2230–0.3274). The lowest detection of DC for polarity change can as low as Δ f   =  0.018 by fluorescent ratiometric signals. More importantly, based on the ultrasensitive changes of lysosomal micro-polarity, DC can be used to real-time estimate cancer cell apoptosis by microscopic imaging and flow cytometry. Thus, DC may have potential application varying from detecting of lysosomal micropolarity changes to real-time estimating of cancer cell apoptosis. [ABSTRACT FROM AUTHOR]

Selenol is a key metabolite of Na 2 SeO 3 and plays an important role in many physiological and pathological processes. The real-time monitoring of selenol is of scientific interest for understanding the anti-cancer mechanism of Na 2 SeO 3 . Based on selenol's ability to specifically break Au S bonds and form more stable Au Se bonds on the surfaces of gold nanoparticles (AuNPs), we developed a novel near-infrared fluorescent nanosensor (Cy5.5-peptide-AuNPs) for detecting selenol. The nanosensor exhibited rapid response to selenol with high selectivity and sensitivity, and it was successfully used to image changes in the selenol level in HepG2 cells during Na 2 SeO 3 -induced apoptosis. Moreover, in vivo fluorescence imaging of selenol was obtained from H22 tumor-bearing mice injected with both the nanosensor and sodium selenite. The results showed that the tumor cell apoptosis induced by Na 2 SeO 3 is correlated with high-level of selenol under hypoxic conditions. We believe that this nanosensor could serve as a powerful tool for monitoring selenol and exploring the physiological function of selenol in a variety of physiological and pathological contexts and that the probe-designed strategy will provide a new platform for research on relevant selenium chemistry. [ABSTRACT FROM AUTHOR]

Phenotypic screening of high quality compound library is an effective strategy to discover novel bioactive molecules. Previously, we developed the divergent organocatalytic cascade approach to efficiently construct a focused library with scaffold diversity and successfully identified a novel spiropyrazolone antitumor scaffold. Herein, a series of spiropyrazolone derivatives were designed, synthesized and assayed. Most of them showed good in vitro antitumor activity with a broad spectrum. Preliminary structure–activity relationship for the substitutions and the stereo configuration were obtained. Compound 5k showed good antitumor activity and could effectively induce cancer cell apoptosis, which represents a good starting point for the development of novel antitumor agents. [ABSTRACT FROM AUTHOR]

Background/Aims: Thyroid carcinoma (TC) is a highly lethal malignant cancer and its carcinogenesis remains undetermined. Dysregulation of microRNAs (miRNAs) is well known to be involved in the development of various cancers, including TC, whereas a role of miR-3666 in the pathogenesis of TC has not been appreciated. Methods: We analyzed the levels of MET and miR-3666 in TC tissue and the relationship of miR-3666 levels with patients' prognosis. We then overexpressed miR-3666 by miRNA mimics transfection and inhibited miR-3666 by miRNA antisense transfection in TC cells. Cell survival and growth were analyzed by CCK-8 assay and MTT assay, respectively. Cell apoptosis and proliferation were analyzed by flow cytometry. Bioinformatics analyses were applied to predict miR-3666 targets, which was then confirmed using luciferase reporter assay. Results: We detected significantly higher levels of MET, and significantly lower levels of miR-3666 in TC tissue, compared to the adjacent nontumor tissue. Moreover, the low miR-3666 levels were associated with poor survival of the patients. Overexpression of miR-3666 significantly inhibited cell growth, while depletion of miR-3666 increased cell growth in TC cells. Moreover, the effects of miR-3666 on cell growth appeared to result from alteration in cell proliferation, rather than changes in cell apoptosis. MiR-3666 was found to bind to the 3'-UTR of MET mRNA to inhibit its translation in TC cells. Conclusion: Reduced miR-3666 levels in TC tissue may promotes TC growth, possibly through MET-mediated cell proliferation. [ABSTRACT FROM AUTHOR]

Thyroid carcinoma (TC) is a lethal cancer worldwide, whereas its carcinogenesis is not fully understood. Although growing evidence has demonstrated that dysregulation of microRNAs (miRNAs) contributes to the development of various cancers, the role of miRNAs in the pathogenesis of TC is poorly characterized. Here, we analyzed the levels of miR-449b in TC tissues and detected significantly lower miR-449b levels in TC tissues. Moreover, the low miR-449b levels were associated with poor survival. We then overexpressed miR-449b by miRNA mimic transfection and inhibited miR-449b by miRNA antisense transfection. Cell growth was analyzed by CCK-8 assay and MTT assay, and apoptosis and cell proliferation were analyzed by flow cytometry. Overexpression of miR-449b significantly inhibited cell growth, while depletion of miR-449b increased cell growth. Moreover, the effects of miR-449b on cell growth were through modulation of cell proliferation rather than through modulation of cell apoptosis. Targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay, showing that miR-449b binds to the 3′-UTR of MET (hepatocyte growth factor receptor) mRNA, to inhibit its expression in TC cells. MET levels were regulated by miR-449b in TT cells. Together, we show that reduced miR-449b levels in TT tissues may promote TC growth, through MET-mediated cell proliferation. [ABSTRACT FROM AUTHOR]

Using whole-cell patch-clamp technique, we investigated influence of selected compounds from groups of prenylated chalcones and flavonoids: xanthohumol and isoxanthohumol on the activity of Kv1.3 channels in human leukemic Jurkat T cells. Obtained results provide evidence that both examined compounds were inhibitors of Kv1.3 channels in these cells. The inhibitory effects occurred in a concentration-dependent manner. The estimated value of the half-blocking concentration (EC) was about 3 μM for xanthohumol and about 7.8 μM for isoxanthohumol. The inhibition of Kv1.3 channels by examined compounds was not complete. Upon an application of the compounds at the maximal concentrations equal to 30 μM, the activity of Kv1.3 channels was inhibited to about 0.13 of the control value. The inhibitory effect was reversible. The application of xanthohumol and isoxanthohumol did not change the currents' activation and inactivation rate. These results may confirm our earlier hypothesis that the presence of a prenyl group in a molecule is a factor that facilitates the inhibition of Kv1.3 channels by compounds from the groups of flavonoids and chalcones. The inhibition of Kv1.3 channels might be involved in antiproliferative and proapoptotic effects of the compounds observed in cancer cell lines expressing these channels. [ABSTRACT FROM AUTHOR]

Abstract: The goal of this study was to monitor the anti-proliferative activity of Rosmarinus officinalis and Salvia officinalis extracts against cancer cells and to correlate this activity with their phytochemical profiles using liquid chromatography/diode array detection/electrospray ion trap tandem mass spectrometry (LC/DAD/ESI-MS n ). For the quantitative estimation of triterpenic acids in the crude extracts an NMR based methodology was used and compared with the HPLC measurements, both applied for the first time, for the case of betulinic acid. Both extracts exerted cytotoxic activity through dose-dependent impairment of viability and mitochondrial activity of rat insulinoma m5F (RINm5F) cells. Decrease of RINm5F viability was mediated by nitric oxide (NO)-induced apoptosis. Importantly, these extracts potentiated NO and TNF-α release from macrophages therefore enhancing their cytocidal action. The rosemary extract developed more pronounced antioxidant, cytotoxic and immunomodifying activities, probably due to the presence of betulinic acid and a higher concentration of carnosic acid in its phytochemical profile. [Copyright &y& Elsevier]

Using the whole-cell patch-clamp technique, we investigated the influence of 8-prenylnaringenin on the activity of the voltage-gated Kv1.3 potassium channels in the human leukemic T lymphocyte cell line Jurkat. 8-prenylnaringenin is a potent plant-derived phytoestrogen that has been found to inhibit cancer cell proliferation. The results show that it inhibited the Kv1.3 channels in a concentration-dependent manner. Complete inhibition occurred at concentrations higher than 10 μM. The inhibitory effect of 8-prenylnaringenin was reversible. It was accompanied by a significant acceleration of channel inactivation without any pronounced change in the activation rate. Of the naringenin derivatives tested to date, 8-prenylnaringenin is the most potent inhibitor of the Kv1.3 channels. The potency of the inhibition may be due to the presence of a prenyl group in the molecule of this flavonoid. The inhibition of the Kv1.3 channels might be involved in the antiproliferative and pro-apoptotic effects of 8-prenylnaringenin that have been observed in cancer cell lines expressing these channels. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we demonstrate a simple two-pot approach to double mesoporous core–shell silica spheres (DMCSSs) with uniform size of 245–790nm, shell thickness of 41–80nm and surface area and total pore volume of 141–618m2 g−1 and 0.14–0.585ccg−1, respectively. First, solid silica spherical particles were synthesized by the Stöber method and used as a core. Second, a mesoporous shell could be formed around the silica cores by using an anionic surfactant and a co-structure directing agent. It was found that mesopores can be anchored within dense silica cores during mesoporous silica shell formation, synchronously the base group with surfactant assistant can etch the dense silica cores to re-organize new mesostructure, so that double mesoporous core–shell silica sphere (DMCSS) structure can be obtained by a single surfactant-templating step. The spherical size and porosity of the silica cores of DMCSS together with shell thickness can be tuned by controlling Stöber parameters, including the concentrations of ammonia, solvent and tetraethoxysilane and the reaction time. DMCSS were loaded with ketoprofen and thymoquinone, which are an anti-inflammatory and a potential novel anti-cancer drug, respectively. Both drugs showed controlled release behavior from the pores of DMCSS. Drug uptakes within DMCSS were ∼27 and 81wt.% for ketoprofen and thymoquinone, respectively. Furthermore, DMCSS loaded with thymoquinone was more effective in inducing cancer cell apoptosis than uncontained thymoquinone, because of the slow release of the drug from the mesoporous structure. [Copyright &y& Elsevier]

A novel approach for phototherapy is proposed. The proposed method is based on cell apoptosis according to halting activation of cancer cell membrane receptor by exposure to UV light pulses without any side effect. In the proposed method, gold nanoparticles are directed to cancerous cells by conjugating their surface with specific ligands. UV light is created locally adjacent to cells around the gold nanoparticles. UV light is generated due to nonlinear interaction of visible light with gold nanoparticles because of enhancement in third order nonlinear effects. For example, by using 780 nm laser, 260 nm UV will be generated around the nanoparticle because of third harmonic generation process. As the generated UV is localized around the cell, there will be no side effect for other cells. We have numerically analyzed the proposed method by solving Maxwell's equation considering third order nonlinear susceptibility and dispersion behavior of permittivity by 3D nonlinear finite difference time domain using Newton-Raphson method. Simulation results for different geometries show that UV light will be generated around gold nanoparticle and it is maximum in hot spots where electric field enhancement occurs. Simulation results illustrate that there is neither UV irradiation side effect to healthy cells, nor harmful temperature rise. [ABSTRACT FROM AUTHOR]

• Voltage-gated potassium channels Kv1.3 are important in normal and cancer tissues. • Inhibition of the channels may find application in therapy of some cancer disorders. • Simvastatin, mevastatin and pravastatin inhibit Kv1.3 channels in cancer cells. • The strongest channel inhibitor is simvastatin and the weakest is pravastatin. • The channel inhibition may be involved in anti-cancer activity of the statins. Voltage-gated potassium channels are integral membrane proteins selectively permeable for potassium ions and activated upon change of membrane potential. Voltage-gated potassium channels of the Kv1.3 type were discovered both in plasma membrane and in inner mitochondrial membrane (mito Kv1.3 channels). For some time Kv1.3 channels located both in plasma membrane and in mitochondria are considered as a potentially new molecular target in several pathologies including some cancer disorders. Lipophilic nontoxic organic inhibitors of Kv1.3 channels may potentially find a clinical application to support therapy of some cancer diseases such as breast, pancreas and lung cancer, melanoma or chronic lymphocytic leukaemia (B-CLL). Inhibition of T lymphocyte Kv1.3 channels may be also important in treatment of chronic and acute respiratory diseases including severe pulmonary complication in corona virus disease Covid 19, however further studies are needed to confirm this supposition. Statins are small-molecule organic compounds, which are lipophilic and are widely used in treatment of hypercholesterolemia and atherosclerosis. Electrophysiological studies performed in our laboratory showed that statins: pravastatin, mevastatin and simvastatin are effective inhibitors of Kv1.3 channels in cancer cells of human T cell line Jurkat. We showed that application of the statins in the concentration range from 1.5 μM to 50 μM inhibited the channels in a concentration-dependent manner. The inhibitory effect was the most potent in case of simvastatin and the least potent in case of pravastatin. The inhibition was partially irreversible in case of simvastatin and fully reversible in case of pravastatin and mevastatin. It was accompanied by a significant acceleration of the current inactivation rate without any significant change of the activation rate. Mechanism of the inhibition is probably complex, including a direct interaction with the channel protein and perturbation of lipid bilayer structure, leading to stabilization of the inactivated state of the channels. Image, graphical abstract [ABSTRACT FROM AUTHOR]

GPR55 is a GPCR of the non-CB1/CB2 cannabinoid receptor family, which is activated by lysophosphatidylinositol (LPI) and stimulates the proliferation of cancer cells. Anandamide, a bioactive lipid endocannabinoid, acts as a biased agonist of GPR55 and induces cancer cell death, but is unstable and psychoactive. We hypothesized that other endocannabinoids and structurally similar compounds, which are more hydrolytically stable, could also induce cancer cell death via GPR55 activation. We chemically synthesized and tested a set of fatty acid amides and esters for cell death induction via GPR55 activation. The most active compounds appeared to be N-acyl dopamines, especially N-docosahexaenoyl dopamine (DHA-DA). Using a panel of cancer cell lines and a set of receptor and intracellular signal transduction machinery inhibitors together with cell viability, Ca2+, NO, ROS (reactive oxygen species) and gene expression measurement, we showed for the first time that for these compounds, the mechanism of cell death induction differed from that published for anandamide and included neuronal nitric oxide synthase (nNOS) overstimulation with concomitant oxidative stress induction. The combination of DHA-DA with LPI, which normally stimulates cancer proliferation and is increased in cancer setting, had an increased cytotoxicity for the cancer cells indicating a therapeutic potential. [ABSTRACT FROM AUTHOR]

• A fluorescent apoptotic agent (MPSE) was developed for biosensing and theranostic. • MPSE can monitor mitochondrial autophagy via different fluorescence emission with dual-channel. • MPSE via three signal transduction pathways to activate cancer cell apoptosis and inhibit tumor cell proliferation. Activation of cancer cell apoptosis and understanding its working mechanism play a critical role in formulating effective cancer treatment strategies. Herein, we report the design, synthesis, and biological evaluations of a selenium-containing fluorescent apoptotic agent MPSE. MPSE enabled the tracking and imaging of cancer cell apoptosis process. Its emission at 550 nm turned off in the presence of thioredoxin reductase (TrxR) in mitochondria, by forming a non-emissive compound MP. This emission "turn-off" phenomenon allows the monitoring of reactive oxygen species (ROS) induced mitochondria damages. As dysfunctional mitochondria were removed by lysosomes, MP entered lysosomes and its protonation led to bright emissions peaked at 475 nm. The new emission enables the tracking of lysosome activation during the apoptosis process. With the help of MPSE , along with other biological techniques, we have revealed three signal transduction pathways that activate cancer cell apoptosis and inhibit tumor cell proliferation. Our results showed that MPSE was highly useful in elucidating the working mechanism of theranostic-based optical apoptotic agents. We hope that understanding this mechanism will greatly facilitate the development of new cancer treatments. [ABSTRACT FROM AUTHOR]