The MUC1-HIF-1α signaling axis regulates pancreatic cancer pathogenesis through polyamine metabolism remodeling.

Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully understood. In this study, we investigated the role of MUC1, a mucin protein overexpressed in pancreatic cancer, in regulating polyamine metabolism. Utilizing pancreatic cancer patient data, we noted a positive correlation between MUC1 expression and the expression of key polyamine metabolism pathway genes. Functional studies revealed that knockdown of spermidine/spermine N1-acetyltransferase 1 (SAT1), a key enzyme involved in polyamine catabolism, attenuated the oncogenic functions of MUC1, including cell survival and proliferation. We further identified a regulatory axis whereby MUC1 stabilized hypoxia-inducible factor (HIF-1α), leading to increased SAT1 expression, which in turn induced carbon flux into the tricarboxylic acid cycle. MUC1-mediated stabilization of HIF-1α enhanced the promoter occupancy of the latter on SAT1 promoter and corresponding transcriptional activation of SAT1, which could be abrogated by pharmacological inhibition of HIF-1α or CRISPR/Cas9-mediated knockout of HIF1A. MUC1 knockdown caused a significant reduction in the levels of SAT1-generated metabolites, N1-acetylspermidine and N8-acetylspermidine. Given the known role of MUC1 in therapy resistance, we also investigated whether inhibiting SAT1 would enhance the efficacy of FOLFIRINOX chemotherapy. By utilizing organoid and orthotopic pancreatic cancer mouse models, we observed that targeting SAT1 with pentamidine improved the efficacy of FOLFIRINOX, suggesting that the combination may represent a promising therapeutic strategy against pancreatic cancer. This study provides insights into the interplay between MUC1 and polyamine metabolism, offering potential avenues for the development of treatments against pancreatic cancer.

Two novel piperidones induce apoptosis and antiproliferative effects on human prostate and lymphoma cancer cell lines.

Cancer remains the second most common cause of death in the US. Due to a recurrent problem with anticancer drug resistance, there is a current need for anticancer drugs with distinct modes of action for combination drug therapy We have tested two novel piperidone compounds, named 2608 (1-dichloroacetyl - 3,5-bis(3,4-difluorobenzylidene)-4-piperidone) and 2610 (1-dichloroacetyl-3,5-bis(3,4-dichlorobenzylidene)-4-piperidone), for their potential cytotoxicity on numerous human cancer cell lines. We found that both compounds were cytotoxic for breast, pancreatic, leukemia, lymphoma, colon, and fibroblast cell lines, with a cytotoxic concentration 50% (CC50) in the low micromolar to nanomolar concentration range. Further assays focused primarily on an acute lymphoblastic lymphoma and colon cancer cell lines since they were the most sensitive and resistant to the experimental piperidones. The cell death mechanism was evaluated through assays commonly used to detect the induction of apoptosis. These assays revealed that both 2608 and 2610 induced reactive oxygen species (ROS) accumulation, mitochondrial depolarization, and activated caspase-3/7. Our findings suggest that the piperidones induced cell death via the intrinsic apoptotic pathway. Additional assays revealed that both piperidones cause cell cycle alteration in lymphoma and colon cell lines. Both piperidones elicited DNA fragmentation, as evidenced by an increment in the sub-G0/G1 subpopulation in both cell lines. Similar to other related compounds, both piperidones were found to act as proteasome inhibitors by increasing the levels of poly-ubiquitinated proteins in both lymphoma and colon cell lines. Hence, the two piperidones exhibited attractive cytotoxic properties and suitable mechanisms of action, which makes them good candidates as anticancer drugs.

Three novel piperidones exhibit tumor-selective cytotoxicity on leukemia cells via protein degradation and stress-mediated mechanisms.

BACKGROUND: Cancer is an ongoing worldwide health problem. Although chemotherapy remains the mainstay therapy for cancer, it is not always effective and has detrimental side effects. Here, we present piperidone compounds P3, P4, and P5 that selectively target cancer cells via protein- and stress-mediated mechanisms. METHODS: We assessed typical apoptotic markers including phosphatidylserine externalization, caspase-3 activation, and DNA fragmentation through flow cytometry. Then, specific markers of the intrinsic pathway of apoptosis including the depolarization of the mitochondria and the generation of reactive oxygen species (ROS) were investigated. Finally, we utilized western blot techniques, RT-qPCR, and observed the cell cycle profile after compound treatment to evaluate the possible behavior of these compounds as proteasome inhibitors. For statistical analyses, we employed the one-way ANOVA followed by Bonferroni post hoc test. RESULTS: P3, P4, and P5 induce cytotoxic effects towards tumorigenic cells, as opposed to non-cancerous cells, at the low micromolar range. Compound treatment leads to the activation of the intrinsic pathway of apoptosis. The accumulation of poly-ubiquitinated proteins and the pro-apoptotic protein Noxa, both typically observed after proteasome inhibition, occurs after P3, P4, and P5 treatment. The stress-related genes PMAIP1, ATF3, CHAC1, MYC, and HMOX-1 were differentially regulated to contribute to the cytotoxic activity of P3-P5. Finally, compound P5 causes cell cycle arrest at the G2/M phase. CONCLUSION: Taken together, compounds P3, P4, and P5 exhibit strong potential as anticancer drug candidates as shown by strong cytotoxic potential, activation of the intrinsic pathway of apoptosis, and show typical proteasome inhibitor characteristics.

Assessing the Antioxidant Properties of Larrea tridentata Extract as a Potential Molecular Therapy against Oxidative Stress.

Oxidative stress has been linked to neurodegenerative diseases such as Huntington's, Parkinson's, Alzheimer's and amyotrophic lateral sclerosis diseases. Larrea tridentata (LT) also known as Creosote Bush is an evergreen shrub found in the Chihuahuan desert which has been used medicinally by Native American tribes in southwestern North America and the Amerindians of South America. However, studies of the antioxidant capacity of the crude extract of LT towards the discovery of novel molecular therapies bearing antioxidants and drug-like properties are lacking. In this study, we assessed the antioxidant properties of Larrea tridentata, collected specifically from the Chihuahuan desert in the region of El Paso del Norte, TX, USA. LT phytochemicals were obtained from three different extracts (ethanol; ethanol: water (60:40) and water). Then the extracts were evaluated in eight different assays (DPPH, ABTS, superoxide; FRAP activity, nitric oxide, phenolic content, UV visible absorption and cytotoxicity in non-cancerous HS27 cells). The three extracts were not affecting the HS27 cells at concentrations up to 120 µg/mL. Among the three extracts, we found that the mixture of ethanol: water (60:40) LT extract has the most efficient antioxidant properties (IC50 (DPPH at 30 min) = 111.7 ± 3.8 µg/mL; IC50 (ABTS) = 8.49 ± 2.28 µg/mL; IC50 (superoxide) = 0.43 ± 0.17 µg/mL; IC50 (NO) = 230.4 ± 130.4 µg/mL; and the highest phenolic content was estimated to 212.46 ± 7.05 mg GAE/L). In addition, there was a strong correlation between phenolic content and the free-radical scavenging activity assays. HPLC-MS study identified nine compounds from the LT-ethanol: water extract including Justicidin B and Beta peltain have been previously reported as secondary metabolites of Larrea tridentata.

Global survey of cell death mechanisms reveals metabolic regulation of ferroptosis.

Apoptosis is one type of programmed cell death. Increasingly, non-apoptotic cell death is recognized as being genetically controlled, or 'regulated'. However, the full extent and diversity of alternative cell death mechanisms remain uncharted. Here we surveyed the landscape of pharmacologically accessible cell death mechanisms. In an examination of 56 caspase-independent lethal compounds, modulatory profiling showed that 10 compounds induced three different types of regulated non-apoptotic cell death. Optimization of one of those ten resulted in the discovery of FIN56, a specific inducer of ferroptosis. Ferroptosis has been found to occur when the lipid-repair enzyme GPX4 is inhibited. FIN56 promoted degradation of GPX4. FIN56 also bound to and activated squalene synthase, an enzyme involved in isoprenoid biosynthesis, independent of GPX4 degradation. These discoveries show that dysregulation of lipid metabolism is associated with ferroptosis. This systematic approach is a means to discover and characterize novel cell death phenotypes.

The neuroprotective role of ferrostatin-1 under rotenone-induced oxidative stress in dopaminergic neuroblastoma cells.

Endoplasmic reticulum (ER) proteins including protein disulfide isomerase (PDI) are playing crucial roles in maintaining appropriate protein folding. Under nitrosative stress, an excess of nitric oxide (NO) radical species induced the S-nitrosylation of PDI cysteines which eliminate its isomerase and oxidoreductase capabilities. In addition, the S-nitrosylation-PDI complex is the cause of aggregation especially of the α-synuclein (α-syn) protein (accumulation of Lewy-body aggregates). We recently identified a potent antioxidant small molecule, Ferrostatin-1 (Fer-1), that was able to inhibit a non-apoptotic cell death named ferroptosis. Ferroptosis cell death involved the generation of oxidative stress particularly lipid peroxide. In this work, we reported the neuroprotective role of ferrostatin-1 under rotenone-induced oxidative stress in dopaminergic neuroblastoma cells (SH-SY5Y). We first synthesized the Fer-1 and confirmed that it is not toxic toward the SH-SY5Y cells at concentrations up to 12.5 µM. Second, we showed that Fer-1 compound quenched the commercially available stable radical, the 2,2-diphenyl-1-picrylhydrazyl (DPPH), in non-cellular assay at 82 %. Third, Fer-1 inhibited the ROS/RNS generated under rotenone insult in SH-SY5Y cells. Fourth, we revealed the effective role of Fer-1 in ER stress mediated activation of apoptotic pathway. Finally, we reported that Fer-1 mitigated rotenone-induced α-syn aggregation.

Competitive inhibition at the glycine site of the N-methyl-D-aspartate receptor by the anesthetics xenon and isoflurane: evidence from molecular modeling and electrophysiology.

BACKGROUND: Inhibition of N-methyl-D-aspartate (NMDA) receptors by anesthetic gases and vapors may play an important role in anesthesia and neuroprotection. However, the site of action of these agents on the NMDA receptor is unknown. The authors show that xenon and isoflurane compete for the binding of the coagonist glycine on the NMDA receptor NR1 subunit. METHODS: Using a novel application of grand canonical Monte Carlo simulations, the authors predict the binding site of xenon on NMDA receptors. They test this prediction using electrophysiology on recombinant NMDA receptors. RESULTS: The authors' modeling predicts that xenon binds at the glycine site of the NMDA receptor. The authors show that inhibition of NMDA receptors by xenon and isoflurane increases as glycine concentration is decreased, consistent with the prediction of competitive inhibition at the glycine site. Lineweaver-Burk analysis shows that isoflurane inhibition seems purely competitive with glycine, but for xenon, there is an additional component of noncompetitive inhibition. The loss of inhibitory effect of xenon and isoflurane in mutant NR1(F639A)/NR2A receptors is explained by increased glycine affinity of the mutant receptors, and inhibition is restored at low glycine concentrations. CONCLUSIONS: Xenon and isoflurane inhibit NMDA receptors by binding at the same site as the coagonist glycine. This finding may have important implications for general anesthesia and neuroprotection. Neuroprotectants that act at the glycine site of the NMDA receptor antagonists are well tolerated in patients, being devoid of psychotomimetic side effects, and the mechanism of inhibition may play a role in their clinical profile.