Disulfiram attenuates osteoclast differentiation in vitro: a potential antiresorptive agent

Short-chain chlorinated paraffins may induce thymic aging in mice by activating PERK-CHOP

Humans indirectly consume approximately 0.02 mg/kg/day of short-chained chlorinated paraffins (SCCPs) through the environment; however, the thymic senescence/damage induced by SCCPs has not been assessed. In this study, 16 female mice (4-week-old) per group were orally administered 0, 0.01, 0.1, and 1 mg/kg/day of SCCPs for 21 days, and the phenotypes and levels of superoxide dismutase (SOD), malondialdehyde (MDA), Tβ4, αβ TCR, SA-β-Gal, GRP78, PERK/CHOP, P53/P21, and CASPASE-1 of the thymus were assessed as indicators. Another group comprising 16 mice was killed at 4-week-old and these indicators were assessed. Thereafter, the thymuses cultured in vitro were exposed to 0, 14, 140, and 1400 μg/L SCCPs, respectively, and the above indicators were measured after 7-day. Based on the results, the oral administration of ≥0.01 mg/kg/day SCCPs to mice and ≥14 μg/L of SCCPs in medium caused thymic aging features, such as a decrease in the ratio of cortex to medulla, gradual blurring of the boundary between the cortex and medulla, dose-dependent oxidative stress (decreased SOD and increased MDA), and decreased levels of Tβ4 and αβ TCRs in the thymus. The oral administration of ≥1 mg/kg/day of SCCPs also impeded the growth and development of female mice and their thymuses. Exposure to the low levels of SCCPs activated PERK-CHOP in the mouse thymus, which modulated increases in SA-β-Gal, IL-1β, P53, and CASPASE-1 in vivo and in vitro. Overall, environmental levels and human blood concentrations (14.8-1400 μg/L) of SCCPs may induce mouse thymus senescence by activating PERK-CHOP in vivo and in vitro, respectively.

Activation of NF-κB signaling regulates ovariectomy-induced bone loss and weight gain

Postmenopausal women experience bone loss and weight gain. To date, crosstalk between estrogen receptor signals and nuclear factor-κB (NF-κB) has been reported, and estrogen depletion enhances bone resorption by osteoclasts via NF-κB activation. However, it is unclear when and in which tissues NF-κB is activated after menopause, and how NF-κB acts as a common signaling molecule for postmenopausal weight gain and bone loss. Therefore, we examined the role of NF-κB in bone and energy metabolism following menopause. NF-κB reporter mice, which can be used to measure NF-κB activation in vivo, were ovariectomized (OVX) and the luminescence intensity after OVX increased in the metaphyses of the long bones and perigonadal white adipose tissue, but not in the other tissues. OVX was performed on wild-type (WT) and p65 mutant knock-in (S534A) mice, whose mutation enhances the transcriptional activity of NF-κB. Weight gain with worsening glucose tolerance was significant in S534A mice after OVX compared with those of WT mice. The bone density of the sham group in WT or S534A mice did not change, whereas in the S534A-OVX group it significantly decreased due to the suppression of bone formation and increase in bone marrow adipocytes. Disulfiram, an anti-alcoholic drug, suppressed OVX-induced activation of NF-κB in the metaphyses of long bones and white adipose tissue (WAT), as well as weight gain and bone loss. Overall, the activation of NF-κB in the metaphyses of long bones and WAT after OVX regulates post-OVX weight gain and bone loss.

Copper in colorectal cancer: From copper-related mechanisms to clinical cancer therapies

Copper, a trace element and vital cofactor, plays a crucial role in the maintenance of biological functions. Recent evidence has established significant correlations between copper levels, cancer development and metastasis. The strong redox-active properties of copper offer both benefits and disadvantages to cancer cells. The intestinal tract, which is primarily responsible for copper uptake and regulation, may suffer from an imbalance in copper homeostasis. Colorectal cancer (CRC) is the most prevalent primary cancer of the intestinal tract and is an aggressive malignant disease with limited therapeutic options. Current research is primarily focused on the relationship between copper and CRC. Innovative concepts, such as cuproplasia and cuproptosis, are being explored to understand copper-related cellular proliferation and death. Cuproplasia is the regulation of cell proliferation that is mediated by both enzymatic and nonenzymatic copper-modulated activities. Whereas, cuproptosis refers to cell death induced by excess copper via promoting the abnormal oligomerisation of lipoylated proteins within the tricarboxylic acid cycle, as well as by diminishing the levels of iron-sulphur cluster proteins. A comprehensive understanding of copper-related cellular proliferation and death mechanisms offers new avenues for CRC treatment. In this review, we summarise the evolving molecular mechanisms, ranging from abnormal intracellular copper concentrations to the copper-related proteins that are being discovered, and discuss the role of copper in the pathogenesis, progression and potential therapies for CRC. Understanding the relationship between copper and CRC will help provide a comprehensive theoretical foundation for innovative treatment strategies in CRC management.

Endolysosomal impairment by binding of amyloid beta or MAPT/Tau to V-ATPase and rescue via the HYAL-CD44 axis in Alzheimer disease

Impaired activities and abnormally enlarged structures of endolysosomes are frequently observed in Alzheimer disease (AD) brains. However, little is known about whether and how endolysosomal dysregulation is triggered and associated with AD. Here, we show that vacuolar ATPase (V-ATPase) is a hub that mediates proteopathy of oligomeric amyloid beta (Aβ) and hyperphosphorylated MAPT/Tau (p-MAPT/Tau). Endolysosomal integrity was largely destroyed in Aβ-overloaded or p-MAPT/Tau-positive neurons in culture and AD brains, which was a necessary step for triggering neurotoxicity, and treatments with acidic nanoparticles or endocytosis inhibitors rescued the endolysosomal impairment and neurotoxicity. Interestingly, we found that the lumenal ATP6V0C and cytosolic ATP6V1B2 subunits of the V-ATPase complex bound to the internalized Aβ and cytosolic PHF-1-reactive MAPT/Tau, respectively. Their interactions disrupted V-ATPase activity and accompanying endolysosomal activity in vitro and induced neurodegeneration. Using a genome-wide functional screen, we isolated a suppressor, HYAL (hyaluronidase), which reversed the endolysosomal dysfunction and proteopathy and alleviated the memory impairment in 3xTg-AD mice. Further, we found that its metabolite hyaluronic acid (HA) and HA receptor CD44 attenuated neurotoxicity in affected neurons via V-ATPase. We propose that endolysosomal V-ATPase is a bona fide proteotoxic receptor that binds to pathogenic proteins and deteriorates endolysosomal function in AD, leading to neurodegeneration in proteopathy.Abbreviations: AAV, adeno-associated virus; Aβ, amyloid beta; AD, Alzheimer disease; APP, amyloid beta precursor protein; ATP6V0C, ATPase H+ transporting V0 subunit c; ATP6V1A, ATPase H+ transporting V1 subunit A; ATP6V1B2, ATPase H+ transporting V1 subunit B2; CD44.Fc, CD44-mouse immunoglobulin Fc fusion construct; Co-IP, co-immunoprecipitation; CTSD, cathepsin D; HA, hyaluronic acid; HMWHA, high-molecular-weight hyaluronic acid; HYAL, hyaluronidase; i.c.v, intracerebroventricular; LMWHA, low-molecular-weight hyaluronic acid; NPs, nanoparticles; p-MAPT/Tau, hyperphosphorylated microtubule associated protein tau; PI3K, phosphoinositide 3-kinase; V-ATPase, vacuolar-type H+-translocating ATPase; WT, wild-type.

Copper metabolism and hepatocellular carcinoma: current insights

Copper is an essential trace element that acts as a cofactor in various enzyme active sites in the human body. It participates in numerous life activities, including lipid metabolism, energy metabolism, and neurotransmitter synthesis. The proposal of "Cuproptosis" has made copper metabolism-related pathways a research hotspot in the field of tumor therapy, which has attracted great attention. This review discusses the biological processes of copper uptake, transport, and storage in human cells. It highlights the mechanisms by which copper metabolism affects hepatocellular carcinogenesis and metastasis, including autophagy, apoptosis, vascular invasion, cuproptosis, and ferroptosis. Additionally, it summarizes the current clinical applications of copper metabolism-related drugs in antitumor therapy.

TT-10 may elevate YAP and repair mouse uterine damage resulting from the inhibition effect of ibuprofen on COX2-PGE2 and YAP

Ibuprofen (IBU) is an emerging environmental contaminant that, in high doses, can damage reproductive organs in humans and other mammals. Recently, its effects on the uterus have been investigated. It is known that the COX2-PGE2 pathway and Yes-associated protein (YAP) are involved in female reproductive organ development and form a COX2-PGE2-EP2-Gas-β-catenin-YAP-COX2 positive feedback loop, in addition, TT-10, a pharmacological product, has been found to increase YAP. In this study, IBU was orally administrated to female mice for 7 d at doses of 0, 50, 100, and 200 mg/kg·bw/day (control, low, medium, and high doses, respectively). In addition, 0, 50, 100, and 200 μmol/L IBU was added in vitro to cultured uterine cells for 7 d at control, low, medium, and high doses, respectively; then, 0, 5, 10, and 20 μmol/L TT-10 were given to the in vitro uterine culture containing 100 μmol/L IBU to observe the effect of YAP activation. The results showed that medium and high doses of IBU inhibited the COX2-PGE2 pathway, decreasing YAP and increasing pYAP, leading to reduced circPVT1, elevated miR-149, and increased apoptosis, ultimately damaging the uterus. Conversely, 10 μmol/L TT-10 maximally enhanced YAP, which regulated COX2-PGE2 pathway activation, increased circPVT1, and decreased miR-149, and promoted cell proliferation, preventing uterine damage. This suggests that IBU may cause uterine damage by inhibiting the COX2-PGE2 pathway and YAP, and that appropriate doses of TT-10 may repair this damage by elevating YAP and stimulating COX2 via the feedback loop.

Disulfiram/Cu Kills and Sensitizes BRAF-Mutant Thyroid Cancer Cells to BRAF Kinase Inhibitor by ROS-Dependently Relieving Feedback Activation of MAPK/ERK and PI3K/AKT Pathways

BRAF^V600E, the most common genetic alteration, has become a major therapeutic target in thyroid cancer. Vemurafenib (PLX4032), a specific inhibitor of BRAF^V600E kinase, exhibits antitumor activity in patients with BRAF^V600E-mutated thyroid cancer. However, the clinical benefit of PLX4032 is often limited by short-term response and acquired resistance via heterogeneous feedback mechanisms. Disulfiram (DSF), an alcohol-aversion drug, shows potent antitumor efficacy in a copper (Cu)-dependent way. However, its antitumor activity in thyroid cancer and its effect on cellular response to BRAF kinase inhibitors remain unclear. Antitumor effects of DSF/Cu on BRAF^V600E-mutated thyroid cancer cells and its effect on the response of these cells to BRAF kinase inhibitor PLX4032 were systematically assessed by a series of in vitro and in vivo functional experiments. The molecular mechanism underlying the sensitizing effect of DSF/Cu on PLX4032 was explored by Western blot and flow cytometry assays. DSF/Cu exhibited stronger inhibitory effects on the proliferation and colony formation of BRAF^V600E-mutated thyroid cancer cells than DSF treatment alone. Further studies revealed that DSF/Cu killed thyroid cancer cells by ROS-dependent suppression of MAPK/ERK and PI3K/AKT signaling pathways. Our data also showed that DSF/Cu strikingly increased the response of BRAF^V600E-mutated thyroid cancer cells to PLX4032. Mechanistically, DSF/Cu sensitizes BRAF-mutant thyroid cancer cells to PLX4032 by inhibiting HER3 and AKT in an ROS-dependent way and subsequently relieving feedback activation of MAPK/ERK and PI3K/AKT pathways. This study not only implies potential clinical use of DSF/Cu in cancer therapy but also provides a new therapeutic strategy for BRAF^V600E-mutated thyroid cancers.

A critical assessment of the potential of pharmacological modulation of aldehyde dehydrogenases to treat the diseases of bone loss

Chronic alcoholism (CA) decreases bone mass and increases the risk of hip fracture. Alcohol and its main metabolite, acetaldehyde impairs osteoblastogenesis by increasing oxidative stress. Aldehyde dehydrogenase (ALDH) is the rate-limiting enzyme in clearing acetaldehyde from the body. The clinical relevance of ALDH in skeletal function has been established by the discovery of single nucleotide polymorphism, SNP (rs671) in the ALDH2 gene giving rise to an inactive form of the enzyme (ALDH2*2) that causes increased serum acetaldehyde and osteoporosis in the affected individuals. Subsequent mouse genetics studies have replicated human phenotype in mice and confirmed the non-redundant role of ALDH2 in bone homeostasis. The activity of ALDH2 is amenable to pharmacological modulation. ALDH2 inhibition by disulfiram (DSF) and activation by alda-1 cause reduction and induction of bone formation, respectively. DSF also inhibits peak bone mass accrual in growing rats. On the other hand, DSF showed an anti-osteoclastogenic effect and protected mice from alcohol-induced osteopenia by inhibiting ALDH1a1 in bone marrow monocytes. Besides DSF, there are several classes of ALDH inhibitors with disparate skeletal effects. Alda-1, the ALDH2 activator induced osteoblast differentiation by increasing bone morphogenic protein 2 (BMP2) expression via ALDH2 activation. Alda-1 also restored ovariectomy-induced bone loss. The scope of structure-activity based studies with ALDH2 and the alda-1-like molecule could lead to the discovery of novel osteoanabolic molecules. This review will critically discuss the molecular mechanism of the ethanol and its principal metabolite, acetaldehyde in the context of ALDH2 in bone cells, and skeletal homeostasis.

The combination of disulfiram and copper for cancer treatment

Disulfiram (DSF) is a thiuram derivative that was developed to treat alcoholism but was also found to have antitumor activity. Copper (Cu), as a trace metal, has important roles in the body. Numerous studies have shown that the combination of DSF and copper (DSF/Cu) greatly enhances its antitumor efficacy. Given that the efficacy of DSF is well established and its safety profile is understood, repurposing DSF as a new anticancer drug is a promising strategy. Here, we summarize the pharmacological effects of DSF and the role of Cu in cancer, and focus on the antitumor effect of DSF/Cu, especially the mechanisms involved in enhancing drug sensibility by targeting specific molecules. We also provide rational strategies for using DSF as a cancer therapy.

Disulfiram suppressed ethanol promoted RANKL-induced osteoclastogenesis in vitro and ethanol-induced osteoporosis in vivo via ALDH1A1-NFATc1 axis

Excessive alcohol consumption is positively related to osteoporosis, and its treatment strategies are poorly developed. Disulfiram inhibits receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis; however, whether it can be used for ethanol-induced osteoclastogenesis and its underlying mechanism are still unclear. In this study, we demonstrated that ethanol promoted RANKL-induced osteoclast formation and bone resorption, whereas, disulfiram suppressed ethanol-induced osteoclastogenesis by abrogating the expression of nuclear factor of activated T cell c1 (NFATc1) in vitro. Further analysis revealed that aldehyde dehydrogenase 1A1 (ALDH1A1) is important for the expression of NFATc1, the master regulator of osteoclast differentiation. Furthermore, we showed that disulfiram protected ethanol-induced osteoporosis in vivo. Overall, our study provides promising evidence that disulfiram can be used as a treatment strategy for alcohol-related osteoporosis via the ALDH1A1T–NFATc1 axis.

Alexidine Dihydrochloride Attenuates Osteoclast Formation and Bone Resorption and Protects Against LPS-Induced Osteolysis

Aseptic loosening and periprosthetic infection leading to inflammatory osteolysis is a major complication associated with total joint arthroplasty (TJA). The liberation of bacterial products and/or implant-derived wear particles activates immune cells that produce pro-osteoclastogenic cytokines that enhance osteoclast recruitment and activity, leading to bone destruction and osteolysis. Therefore, agents that prevent the inflammatory response and/or attenuate excessive osteoclast (OC) formation and bone resorption offer therapeutic potential by prolonging the life of TJA implants. Alexidine dihydrochloride (AD) is a bisbiguanide compound commonly used as an oral disinfectant and in contact lens solutions. It possesses antimicrobial, anti-inflammatory and anticancer properties; however, its effects on OC biology are poorly described. Here, we demonstrate that AD inhibits OC formation and bone resorption in vitro and exert prophylatic protection against LPS-induced osteolysis in vivo. Biochemical analysis demonstrated that AD suppressed receptor activator of NF-κB ligand (RANKL)-induced activation of mitogen-activated protein kinases (ERK, p38, and JNK), leading to the downregulation of NFATc1. Furthermore, AD disrupted F-actin ring formation and attenuated the ability of mature OC to resorb bone. Collectively, our findings suggest that AD may be a promising prophylactic anti-osteoclastic/resorptive agent for the treatment of osteolytic diseases caused by excessive OC formation and function.