HDAC6 inhibition reverses long-term doxorubicin-induced cognitive dysfunction by restoring microglia homeostasis and synaptic integrity

CCR5 antagonist maraviroc alleviates doxorubicin-induced neuroinflammation and neurobehavioral deficiency by regulating NF-κB/NLRP3 signaling in a breast cancer mouse model

The chemotherapeutic agent Doxorubicin (DOX) is known to cause chemotherapy-induced cognitive impairment (CICI). Maraviroc, a potent C-C chemokine receptor 5 (CCR5) antagonist, shows neuroprotective properties, while its role in CICI remains unclear. This study determined the therapeutic potential of maraviroc on CICI. Adult C57BL/6J mice with implanted breast cancer cells received four weekly intraperitoneal injections of saline (Control group), 5 mg/kg DOX (DOX group), 10 mg/kg maraviroc (MVC group), or 5 mg/kg DOX with 10 mg/kg maraviroc (DOX + MVC group). The Morris Water Maze (MWM) was used for neurobehavioural test. Western blot analysis and immunofluorescence were used to evaluate the expressions of inflammatory markers, apoptosis-related proteins, and synaptic-related proteins. The volume and weight of tumor were also evaluated after treatments. DOX treatment significantly increased chemokines (CCL3, CCL4) and inflammatory cytokines (IL-1β, TNF-α) in tumor-bearing mice hippocampus. While maraviroc administration reduced hippocampal proinflammatory factors compared to the DOX group. Furthermore, it also lowered apoptosis markers, restored synaptic proteins levels, and inhibited the NF-κB/NLRP3 pathway. Accordingly, maraviroc treatment significantly improved DOX-induced neurobehavioural impairments as evidenced by an increased number of platform crossings and percentage of target quadrant time in the MWM test. Additionally, when combined with DOX, maraviroc had additional inhibitory effects on tumor growth. These findings suggest that maraviroc can mitigate DOX-induced CICI by suppressing elevated proinflammatory chemokines and cytokines through the NF-κB/NLRP3 pathway, potentially offering an anti-tumor benefit. This research presents a promising therapeutic approach for DOX-induced CICI, enhancing the safety and efficacy of cancer treatments.

Systemic and targeted activation of Nrf2 reverses doxorubicin-induced cognitive impairments and sensorimotor deficits in mice

While cancer survivorship has increased due to advances in treatments, chemotherapy often carries long-lived neurotoxic side effects which reduce quality of life. Commonly affected domains include memory, executive function, attention, processing speed and sensorimotor function, colloquially known as chemotherapy-induced cognitive impairment (CICI) or "chemobrain". Oxidative stress and neuroimmune signaling in the brain have been mechanistically linked to the deleterious effects of chemotherapy on cognition and sensorimotor function. With this in mind, we tested if activation of the master regulator of antioxidant response nuclear factor E2-related factor 2 (Nrf2) alleviates cognitive and sensorimotor impairments induced by doxorubicin. The FDA-approved systemic Nrf2 activator, diroximel fumarate (DRF) was used, along with our recently developed prodrug 1c which has the advantage of specifically releasing monomethyl fumarate at sites of oxidative stress. DRF and 1c both reversed doxorubicin-induced deficits in executive function, spatial and working memory, as well as decrements in fine motor coordination and grip strength, across both male and female mice. Both treatments reversed doxorubicin-induced loss of synaptic proteins and microglia phenotypic transition in the hippocampus. Doxorubicin-induced myelin damage in the corpus callosum was reversed by both Nrf2 activators. These results demonstrate the therapeutic potential of Nrf2 activators to reverse doxorubicin-induced cognitive impairments, motor incoordination, and associated structural and phenotypic changes in the brain. The localized release of monomethyl fumarate by 1c has the potential to diminish unwanted effects of fumarates while retaining efficacy.

UBE2N promotes cell viability and glycolysis by promoting Axin1 ubiquitination in prostate cancer cells

BACKGROUND

Ubiquitin-conjugating enzyme E2 N (UBE2N) is recognized in the progression of some cancers; however, little research has been conducted to describe its role in prostate cancer. The purpose of this paper is to explore the function and mechanism of UBE2N in prostate cancer cells.

METHODS

UBE2N expression was detected in Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) data, prostate cancer tissue microarrays, and prostate cancer cell lines, respectively. UBE2N knockdown or overexpression was used to analyze its role in cell viability and glycolysis of prostate cancer cells and tumor growth. XAV939 or Axin1 overexpression was co-treated with UBE2N overexpression to detect the involvement of the Wnt/β-catenin signaling and Axin1 in the UBE2N function. UBE2N interacting with Axin1 was analyzed by co-immunoprecipitation assay.

RESULTS

UBE2N was upregulated in prostate cancer and the UBE2N-high expression correlated with the poor prognosis of prostate cancer. UBE2N knockdown inhibited cell viability and glycolysis in prostate cancer cells and restricted tumor formation in tumor-bearing mice. Wnt/β-catenin inhibition and Axin1 overexpression reversed the promoting viability and glycolysis function of UBE2N. UBE2N promoted Axin1 ubiquitination and decreased Axin1 protein level.

Senolytic treatment alleviates doxorubicin-induced chemobrain

Doxorubicin (Dox), a widely used treatment for cancer, can result in chemotherapy-induced cognitive impairments (chemobrain). Chemobrain is associated with inflammation and oxidative stress similar to aging. As such, Dox treatment has also been used as a model of aging. However, it is unclear if Dox induces brain changes similar to that observed during aging since Dox does not readily enter the brain. Rather, the mechanism for chemobrain likely involves the induction of peripheral cellular senescence and the release of senescence-associated secretory phenotype (SASP) factors and these SASP factors can enter the brain to disrupt cognition. We examined the effect of Dox on peripheral and brain markers of aging and cognition. In addition, we employed the senolytic, ABT-263, which also has limited access to the brain. The results indicate that plasma SASP factors enter the brain, activating microglia, increasing oxidative stress, and altering gene transcription. In turn, the synaptic function required for memory was reduced in response to altered redox signaling. ABT-263 prevented or limited most of the Dox-induced effects. The results emphasize a link between cognitive decline and the release of SASP factors from peripheral senescent cells and indicate some differences as well as similarities between advanced age and Dox treatment.

TDP43/HDAC6/Prdx1 signaling pathway participated in the cognitive impairment of obstructive sleep apnea via regulating inflammation and oxidative stress

Neuroinflammation and oxidative stress induced by intermittent hypoxia (IH) are associated with cognitive dysfunction in patients with obstructive sleep apnea (OSA). Recently, TAR DNA-binding protein 43 (TDP-43), histone deacetylase 6 (HDAC6), and peroxiredoxin 1 (Prdx1) have been reported to be involved in cognitive impairment in many degenerative diseases; however, the underlying mechanisms remain unclear. In the present study, subjects underwent polysomnography to diagnose OSA. Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA) and peripheral blood samples were collected. HMC3 cells were treated with lipopolysaccharide (LPS) to mimic in vitro neuroinflammation. Western blotting was used to assess protein expression and ELISA to assess inflammation and oxidative stress levels. Participants were divided into three groups: healthy control (n = 20); mild to moderate OSA (n = 20); and severe OSA (n = 20). The MoCA scores in mild-moderate OSA and severe OSA were lower than those in healthy controls. Continuous positive airway pressure therapy was found to be effective for cognitive impairment in subjects with severe OSA (24.70 ± 1.81). Expression of TDP-43 and HDAC6 was increased in subjects with OSA, whereas Prdx1 expression was decreased. Alterations in these proteins were partially reversed after 12 weeks of CPAP treatment. Protein expression of TDP-43 and HDAC6 was negatively correlated with MoCA scores in patients with OSA, while Prdx1 expression exhibited the opposite trend. In LPS-treated HMC3 cells, TDP-43 and HDAC6 were upregulated, whereas Prdx1 expression was reduced. TDP-43 influenced the expression of Prdx1 by regulating HDAC6, and inflammation and oxidative stress varied with the expression of TDP-43. When a specific inhibitor of HDAC6 was used, LPS-induced inflammation and oxidative stress were alleviated by an elevated level of Prdx1. In summary, findings of the present study suggest that TDP-43 influenced Prdx1 by regulating HDAC6 expression and promoting neuroinflammation and oxidative stress. This process may be involved in the cognitive impairment experienced by patients with OSA and may provide potential therapeutic targets.

SMAD4 inhibits glycolysis in ovarian cancer through PI3K/AKT/HK2 signaling pathway by activating ARHGAP10

BACKGROUND

ARHGAP10 is a tumor-suppressor gene related to ovarian cancer (OC) progression; however, its specific mechanism is unclear.

AIMS

To investigate the effect of ARHGAP10 on OC cell migration, invasion, and glycolysis.

METHODS AND RESULTS

Quantitative real-time PCR (qRT-PCR) quantified mRNA and protein expressions of AKT, p-AKT, HK2, and SMAD4 were tested by Western blot. EdU, Wound healing, and Transwell assay were utilized to evaluate OC cell proliferation, migration, and invasion. We used a Seahorse XF24 Extracellular Flux Analyzer to monitor cellular oxygen consumption rates (OCR) and extracellular acidification rates (ECAR). Chromatin immunoprecipitation (ChIP) was used to analyze the transcriptional regulation of ARHGAP10 by SMAD4. ARHGAP10 expression in OC tissues was detected by immunohistochemistry. Our results showed that ARHGAP10 expression was negatively related to lactate levels in human OC tissues. ARHGAP10 overexpression can inhibit the migration, proliferation, and invasion of OC cells, and this function can be blocked by 2-Deoxy-D-glucose. Moreover, we found that ARHGAP10 expression can be rescued with the AKT inhibitor LY294002.

CONCLUSIONS

This study revealed that the antitumor effects of ARHGAP10 in vivo and in vitro possibly suppress oncogenic glycolysis through the PI3K/AKT/HK2-regulated glycolysis metabolism pathway.

Neuroimaging based biotypes for precision diagnosis and prognosis in cancer-related cognitive impairment

Cancer related cognitive impairment (CRCI) is commonly associated with cancer and its treatments, yet the present binary diagnostic approach fails to capture the full spectrum of this syndrome. Cognitive function is highly complex and exists on a continuum that is poorly characterized by dichotomous categories. Advanced statistical methodologies applied to symptom assessments have demonstrated that there are multiple subclasses of CRCI. However, studies suggest that relying on symptom assessments alone may fail to account for significant differences in the neural mechanisms that underlie a specific cognitive phenotype. Treatment plans that address the specific physiologic mechanisms involved in an individual patient's condition is the heart of precision medicine. In this narrative review, we discuss how biotyping, a precision medicine framework being utilized in other mental disorders, could be applied to CRCI. Specifically, we discuss how neuroimaging can be used to determine biotypes of CRCI, which allow for increased precision in prediction and diagnosis of CRCI via biologic mechanistic data. Biotypes may also provide more precise clinical endpoints for intervention trials. Biotyping could be made more feasible with proxy imaging technologies or liquid biomarkers. Large cross-sectional phenotyping studies are needed in addition to evaluation of longitudinal trajectories, and data sharing/pooling is highly feasible with currently available digital infrastructures.

Comprehensive information-based differential gene regulatory networks analysis (CIdrgn): Application to gastric cancer and chemotherapy-responsive gene network identification

Biological condition-responsive gene network analysis has attracted considerable research attention because of its ability to identify pathways or gene modules involved in the underlying mechanisms of diseases. Although many condition-specific gene network identification methods have been developed, they are based on partial or incomplete gene regulatory network information, with most studies only considering the differential expression levels or correlations among genes. However, a single gene-based analysis cannot effectively identify the molecular interactions involved in the mechanisms underlying diseases, which reflect perturbations in specific molecular network functions rather than disorders of a single gene. To comprehensively identify differentially regulated gene networks, we propose a novel computational strategy called comprehensive analysis of differential gene regulatory networks (CIdrgn). Our strategy incorporates comprehensive information on the networks between genes, including the expression levels, edge structures and regulatory effects, to measure the dissimilarity among networks. We extended the proposed CIdrgn to cell line characteristic-specific gene network analysis. Monte Carlo simulations showed the effectiveness of CIdrgn for identifying differentially regulated gene networks with different network structures and scales. Moreover, condition-responsive network identification in cell line characteristic-specific gene network analyses was verified. We applied CIdrgn to identify gastric cancer and itsf chemotherapy (capecitabine and oxaliplatin) -responsive network based on the Cancer Dependency Map. The CXC family of chemokines and cadherin gene family networks were identified as gastric cancer-specific gene regulatory networks, which was verified through a literature survey. The networks of the olfactory receptor family with the ASCL1/FOS family were identified as capecitabine- and oxaliplatin sensitive -specific gene networks. We expect that the proposed CIdrgn method will be a useful tool for identifying crucial molecular interactions involved in the specific biological conditions of cancer cell lines, such as the cancer stage or acquired anticancer drug resistance.

Drug-induced oxidative stress in cancer treatments: Angel or devil?

Oxidative stress (OS), defined as redox imbalance in favor of oxidant burden, is one of the most significant biological events in cancer progression. Cancer cells generally represent a higher oxidant level, which suggests a dual therapeutic strategy by regulating redox status (i.e., pro-oxidant therapy and/or antioxidant therapy). Indeed, pro-oxidant therapy exhibits a great anti-cancer capability, attributing to a higher oxidant accumulation within cancer cells, whereas antioxidant therapy to restore redox homeostasis has been claimed to fail in several clinical practices. Targeting the redox vulnerability of cancer cells by pro-oxidants capable of generating excessive reactive oxygen species (ROS) has surfaced as an important anti-cancer strategy. However, multiple adverse effects caused by the indiscriminate attacks of uncontrolled drug-induced OS on normal tissues and the drug-tolerant capacity of some certain cancer cells greatly limit their further applications. Herein, we review several representative oxidative anti-cancer drugs and summarize their side effects on normal tissues and organs, emphasizing that seeking a balance between pro-oxidant therapy and oxidative damage is of great value in exploiting next-generation OS-based anti-cancer chemotherapeutics.

Spinal HDAC6 mediates nociceptive behaviors induced by chronic constriction injury via neuronal activation and neuroinflammation

Neuropathic pain (NP) is often accompanied by psychiatric comorbidities and currently lacks effective treatment. Prior research has shown that HDAC6 plays a crucial role in pain sensitization, but the specific mechanisms remain unclear. HDAC6 inhibitors have been found to alleviate mechanical allodynia caused by inflammation and peripheral nerve damage. In this study, we investigated the cellular mechanisms of HDAC6 in the development and maintenance of neuropathic pain. Our findings indicate that HDAC6 expression in the spinal cord (SC) is upregulated in a time-dependent manner following chronic constriction injury (CCI). HDAC6 is primarily expressed in neurons and microglia in the spinal cord. CCI-induced HDAC6 production was abolished by intrathecal injection of a microglia inhibitor. ACY-1215, a specific HDAC6 inhibitor, significantly reduced CCI-induced mechanical allodynia, but not thermal hyperalgesia. ACY-1215 also inhibited neuron activation and suppressed CCI-induced pyroptosis and neuroinflammatory responses. In summary, our results suggest that HDAC6 contributes to the development and maintenance of NP through neuronal activation and neuroinflammation. HDAC6 may be a promising target for treating NP.

Protective effect of low-dose radiation on doxorubicin-induced brain injury in mice

BACKGROUND

To investigate the protective effect of low-dose radiation (LDR) on brain injury in mice induced by doxorubicin (DOX).

METHODS

Sixty female BALB/C mice were randomly divided into the control (CTR) group, low-dose radiation (LDR) group, doxorubicin treatment (DOX) group and low-dose radiation before doxorubicin treatment (COM) group. After 72 h of exposure to 75 mGy, the mice were intraperitoneally injected with 7.5 mg/kg of doxorubicin and sacrificed 5 days later. Neuron-specific enolase (NSE), lactate dehydrogenase (LDH), adenosine triphosphate (ATP), neurotransmitters, inflammatory mediators, apoptosis- and oxidative stress-related mediators as well as mitochondrial dysfunction were examined.

RESULTS

Compared to the DOX group, the concentrations of DA, 5-HT, EPI and GABA in the COM group were significantly decreased, and the number of TUNEL-positive cells was decreased. In addition, the expression of proapoptotic proteins was downregulated in the COM group compared to the DOX group. Low-dose radiation in advance reduced reactive oxygen species and activated the SOD antioxidant defense system as indicated by significantly reduced GSH expression, increased GSSG expression, increased GPx expression and activation of the Nrf2 redox pathway. After low-dose radiation, the expression levels of ATP5f1, NDUFV1 and CYC1 were close to normal, and the mitochondrial respiratory control rate (RCR) and activity of respiratory chain complex enzymes also tended to be normal. Low-dose radiation upregulated the expression levels of IL-2 and IL-4 but downregulated the expression levels of IL-10 and TGF-β.

CONCLUSION

LDR has a protective effect on brain injury in mice treated with DOX. The mechanism is related to LDR alleviating mitochondrial dysfunction and oxidative stress, which promotes the production of antioxidant damage proteins, thus exerting an adaptive protective effect on cells.

Upregulation of MDH1 acetylation by HDAC6 inhibition protects against oxidative stress-derived neuronal apoptosis following intracerebral hemorrhage

Oxidative stress impairs functional recovery after intracerebral hemorrhage (ICH). Histone deacetylase 6 (HDAC6) plays an important role in the initiation of oxidative stress. However, the function of HDAC6 in ICH and the underlying mechanism of action remain elusive. We demonstrated here that HDAC6 knockout mice were resistant to oxidative stress following ICH, as assessed by the MDA and NADPH/NADP+ assays and ROS detection. HDAC6 deficiency also resulted in reduced neuronal apoptosis and lower expression levels of apoptosis-related proteins. Further mechanistic studies showed that HDAC6 bound to malate dehydrogenase 1 (MDH1) and mediated-MDH1 deacetylation on the lysine residues at position 121 and 298. MDH1 acetylation was inhibited in HT22 cells that were challenged with ICH-related damaging agents (Hemin, Hemoglobin, and Thrombin), but increased when HDAC6 was inhibited, suggesting an interplay between HDAC6 and MDH1. The acetylation-mimetic mutant, but not the acetylation-resistant mutant, of MDH1 protected neurons from oxidative injury. Furthermore, HDAC6 inhibition failed to alleviate brain damage after ICH when MDH1 was knockdown. Taken together, our study showed that HDAC6 inhibition protects against brain damage during ICH through MDH1 acetylation.