Monoethanolamine-induced glucose deprivation promotes apoptosis through metabolic rewiring in prostate cancer

Zinc ions regulate mitochondrial quality control in neurons under oxidative stress and reduce PANoptosis in spinal cord injury models via the Lgals3-Bax pathway

Spinal cord injury is a serious traumatic nervous system disorder characterized by extensive neuronal apoptosis. Oxidative stress, a key factor in neuronal apoptosis, leads to the accumulation of reactive oxygen species, making mitochondrial quality control within cells crucial. Previous studies have demonstrated zinc's anti-inflammatory and anti-apoptotic properties in protecting mitochondria during spinal cord injury treatment, yet the precise mechanisms remain elusive. Single-cell sequencing analysis has identified Lgals3 and Bax as core genes in apoptosis. This study aimed to investigate whether zinc ions protect intracellular mitochondria by inhibiting the apoptotic proteins Lgals3 and Bax. We elucidated zinc ions' key role in mitigating mitochondrial quality control dysfunction triggered by oxidative stress and confirmed this was achieved by targeting the Lgals3-Bax pathway. Zinc's inhibitory effect on this pathway not only preserved mitochondrial integrity but also significantly reduced PANoptosis after spinal cord injury. Under oxidative stress, zinc ion regulation of mitochondrial quality control reveals an organelle-targeted therapeutic strategy, offering a novel approach for more precise treatment of spinal cord injury.

System Xc- exacerbates metabolic stress under glucose depletion in oral squamous cell carcinoma

OBJECTIVE

Emerging evidence suggests that glucose depletion (GD)-induced cell death depends on system Xc- , a glutamate/cystine antiporter extensively studied in ferroptosis. However, the underlying mechanism remains debated. Our study confirmed the correlation between system Xc- and GD-induced cell death and provided a strategic treatment for oral squamous cell carcinoma (OSCC).

METHODS

qPCR and Western blotting were performed to detect changes in xCT and CD98 expression after glucose withdrawal. Then, the cell viability of OSCCs under the indicated conditions was measured. To identify the GD-responsible transcriptional factors of SLC7A11, we performed a luciferase reporter assay and a ChIP assay. Further, metabolomics was conducted to identify changes in metabolites. Finally, mitochondrial function and ATP production were evaluated using the seahorse assay, and NADP+ /NADPH dynamics were measured using a NADP+ /NADPH kit.

RESULTS

In OSCCs, system Xc- promoted GD-induced cell death by increasing glutamate consumption, which promoted NADPH exhaustion and TCA blockade. Moreover, GD-induced xCT upregulation was governed by the p-eIF2α/ATF4 axis.

CONCLUSIONS

System Xc- overexpression compromised the metabolic flexibility of OSCC under GD conditions, and thus, glucose starvation therapy is effective for killing OSCC cells.

Role of monocarboxylate transporters and glucose transporters in prostate cancer

OBJECTIVES

Currently, research of new diagnostic approaches to detect clinically significant prostate cancer is relevant because of the importance of early detection of aggressive forms of the disease, often challenging, even when using modern diagnostic tools. The aim of this review is to present the current knowledge regarding monocarboxylate transporters' and glucose transporters' expression as a component of glycolytic phenotype definition in prostate cancer cells.

METHODS

We searched PubMed and Scopus databases. Twenty-six articles from 2003 to 2022 were included. Literature research and selection were carried out based on the recommendations of the PRISMA statement.

RESULTS

The presence of "lactate shuttle" in the tumor tissue is associated with a worse prognosis. Increased expression of MCT2, MCT4, GLUT1, and down-regulation of GLUT3 are associated with prostate adenocarcinoma. MCT4 expression level correlates with the grade of tumor malignancy and disease prognosis. Up-regulation of GLUT1 and MCT4 is typical for hormone-resistant prostate cancer. Inhibition of MCT1 and MCT4 and GLUT1 in prostate cancer cells reduces their metabolic activity and growth rate, a suitable novel approach for targeted therapy.

CONCLUSION

Review of the current studies showed that expression of certain MCTs and GLUTs types are associated with prostate cancer and some of them correlate with high malignancy and poor prognosis. Detection by immunohistochemistry of these transporters could represent a new diagnostic tool to identify aggressive forms of prostate cancer, and a novel therapeutic target for selective drugs.

Enhanced apoptosis of HCT116 colon cancer cells treated with extracts from Calotropis gigantea stem bark by starvation

Calotropis gigantea stem bark extract, particularly the dichloromethane fraction (CGDCM), demonstrated the most potent antiproliferative effects on hepatocellular carcinoma HepG2 and colorectal HCT116 cells. The current study focused on enhancing the effectiveness of cancer treatment with CGDCM at concentrations close to the IC50 in HCT116 cells by reducing their nutrient supply. CGDCM (2, 4, and 8 μg/mL) treatment for 24 h under glucose conditions of 4.5 g/L without fetal bovine serum (FBS) supplementation or serum starvation (G+/F-), glucose 0 g/L with 10% FBS or glucose starvation (G-/F+), and glucose 0 g/L with 0% FBS or complete starvation (G-/F-) induced a greater antiproliferative effect in HCT116 cells than therapy in complete medium with glucose 4.5 g/L and 10% FBS (G+/F+). Nonetheless, the anticancer effect of CGDCM at 4 μg/mL under (G-/F-) showed the highest activity compared to other starvation conditions. The three starvation conditions showed a significant reduction in cell viability compared to the control (G+/F+) medium group, while the inhibitory effect on cell viability did not differ significantly among the three starvation conditions. CGDCM at 4 μg/mL in (G-/F-) medium triggered apoptosis by dissipating the mitochondrial membrane potential and arresting cells in the G2/M phase. This investigation demonstrated that a decrease in intracellular ATP and fatty acid levels was associated with enhanced apoptosis by treatment with CGDCM at 4 μg/mL under (G-/F-) conditions. In addition, under (G-/F-), CGDCM at 4 μg/mL increased levels of reactive oxygen species (ROS) and was suggested to primarily trigger apoptosis in HCT116 cells. Thus, C. gigantea extracts may be useful for the future development of alternative, effective cancer treatment regimens.

PLK1 and AURKB phosphorylate survivin differentially to affect proliferation in racially distinct triple-negative breast cancer

Protein diversity due to alternative mRNA splicing or post-translational modifications (PTMs) plays a vital role in various cellular functions. The mitotic kinases polo-like kinase 1 (PLK1) and Aurora B (AURKB) phosphorylate survivin, an inhibitor of apoptosis (IAP) family member, thereby regulating cell proliferation. PLK1, AURKB, and survivin are overexpressed in triple-negative breast cancer (TNBC), an aggressive breast cancer subtype. TNBC is associated with high proliferative capacity, high rates of distant metastasis, and treatment resistance. The proliferation-promoting protein survivin and its activating kinases, PLK1 and AURKB, are overexpressed in TNBC. In this study, we investigated the role of survivin phosphorylation in racial disparities in TNBC cell proliferation. Analysis of TCGA TNBC data revealed higher expression levels of PLK1 (P = 0.026) and AURKB (P = 0.045) in African Americans (AAs; n = 41) than in European Americans (EAs; n = 86). In contrast, no significant racial differences in survivin mRNA or protein levels were observed. AA TNBC cells exhibited higher p-survivin levels than EA TNBC cells. Survivin silencing using small interfering RNAs significantly attenuated cell proliferation and cell cycle progression in AA TNBC cells, but not in EA TNBC cells. In addition, PLK1 and AURKB inhibition with volasertib and barasertib significantly inhibited the growth of AA TNBC xenografts, but not of EA TNBC tumors. These data suggest that inhibition of PLK1 and AURKB suppresses cell proliferation and tumor growth, specifically in AA TNBC. These findings suggest that targeting survivin phosphorylation may be a viable therapeutic option for AA patients with TNBC.

Low doses of fumonisin B1 exacerbate ochratoxin A-induced renal injury in mice and the protective roles of heat shock protein 70

Fumonisin B1 (FB1) and ochratoxin A (OTA) possess nephrotoxicity to animals and widely co-exist in food and feedstuffs. FB1 rarely, while OTA often, causes toxicosis in animals. Heat shock protein 70 (Hsp70) resists lung injury induced by pneumolysin, but whether Hsp70 could remission mycotoxins-induced renal injury is still unknown. The present study aims to explore the impacts of nontoxic doses of FB1 on OTA-induced nephrotoxicity and the protective roles of Hsp70. In the mycotoxins-challenge experiment, ICR mice were co-exposed to nontoxic doses of FB1 (0, 0.2, 0.5, 1.0 mg/kg bw, IP) and toxic dose of OTA (0.4 mg/kg bw, IP) for 16 d. The results showed that the levels of BUN, Cr, MDA in serum, the Cyto C in renal tubes or glomerulus, pro-apoptosis genes and p-JNK protein expression in kidney were significantly increased. Histopathological results revealed the glomerular swelling. The above all indexes were dose-dependent. In the protection experiment, the mice were pretreated with the eukaryotic plasmid of pEGFP-C3-Hsp70, these increasing parameters in the mycotoxins-challenge experiment were reversed. In vitro, after pK-15 cells were treated with 8 μM FB1 and 5 μM OTA for 48 h, the mitochondrial membrane potential was significantly reduced, mitochondrial ROS was remarkably increased, more Cyto C was leaked from mitochondria into cytoplasm, and pro-apoptosis genes were significantly up-regulated. After the Hsp70 level was up-regulated by pEGFP-C3-Hsp70 or ML346 in pK-15 cells, these above indexes were reversed. However, activation of JNK by anisomycin significantly suppressed the protective effects of Hsp70. Our results demonstrate that the nontoxic doses of FB1 exacerbate the toxic dose of OTA-induced renal injury, while Hsp70 alleviates renal injury by inhibiting the JNK/MAPK signaling pathway. Hsp70 up-regulation may be an efficient strategy for protecting against tissue damage and bio-function impairment induced by co-exposure to FB1 and OTA.

The emerging roles of PHOSPHO1 and its regulated phospholipid homeostasis in metabolic disorders

Emerging evidence suggests that phosphoethanolamine/phosphocholine phosphatase 1 (PHOSPHO1), a specific phosphoethanolamine and phosphocholine phosphatase, is involved in energy metabolism. In this review, we describe the structure and regulation of PHOSPHO1, as well as current knowledge about the role of PHOSPHO1 and its related phospholipid metabolites in regulating energy metabolism. We also examine mechanistic evidence of PHOSPHO1- and phospholipid-mediated regulation of mitochondrial and lipid droplets functions in the context of metabolic homeostasis, which could be potentially targeted for treating metabolic disorders.

Exosomal Metabolic Signatures Are Associated with Differential Response to Neoadjuvant Chemotherapy in Patients with Breast Cancer

Neoadjuvant chemotherapy (NAC) is commonly used in breast cancer (BC) patients to increase eligibility for breast-conserving surgery. Only 30% of patients with BC show pathologic complete response (pCR) after NAC, and residual disease (RD) is associated with poor long-term prognosis. A critical barrier to improving NAC outcomes in patients with BC is the limited understanding of the mechanisms underlying differential treatment outcomes. In this study, we evaluated the ability of exosomal metabolic profiles to predict NAC response in patients with BC. Exosomes isolated from the plasma of patients after NAC were used for metabolomic analyses to identify exosomal metabolic signatures associated with the NAC response. Among the 16 BC patients who received NAC, eight had a pCR, and eight had RD. Patients with RD had 2.52-fold higher exosome concentration in their plasma than those with pCR and showed significant enrichment of various metabolic pathways, including citrate cycle, urea cycle, porphyrin metabolism, glycolysis, and gluconeogenesis. Additionally, the relative exosomal levels of succinate and lactate were significantly higher in patients with RD than in those with pCR. These data suggest that plasma exosomal metabolic signatures could be associated with differential NAC outcomes in BC patients and provide insight into the metabolic determinants of NAC response in patients with BC.