Anemone rivularis inhibits pyruvate dehydrogenase kinase activity and tumor growth

TIGD1 Function as a Potential Cuproptosis Regulator Following a Novel Cuproptosis-Related Gene Risk Signature in Colorectal Cancer

Cuproptosis is a new form of copper-dependent programmed cell death commonly occurring within the body. There is emerging evidence indicating that cuproptosis has a significant regulatory function in the onset and progression of cancer. However, it is still unclear how cuproptosis regulates cancer and whether other genes are involved in the regulation. Using the TCGA-COAD dataset of 512 samples, we found that seven of ten cuproptosis markers showed prognostic value in colorectal cancer (CRC) using Kaplan-Meier survival analysis. Furthermore, 31 prognostic cuproptosis-related genes were identified using weighted gene co-expression network analysis and univariate Cox analysis. Subsequently, we constructed a 7-PCRG signature using least absolute shrinkage and selection operator (LASSO)-Cox regression analysis. The risk score predicting survival in patients with CRC was evaluated. Two risk groups were classified based on their risk scores. The two groups revealed a significant difference in immune cells, such as B and T cells. Furthermore, we identified differences in many immune functions and checkpoints, including CD276 and CD28. In vitro experiments showed that a hub cuproptosis-related gene, TIGD1, could significantly regulate cuproptosis in CRC after exposure to elesclomol. This study validated that cuproptosis was closely related to the progression of CRC. Seven new cuproptosis-related genes were identified, and the function of TIGD1 in cuproptosis was preliminarily understood. Since a certain concentration of copper in CRC cells is important, cuproptosis may provide a new target for cancer therapy. This study may provide novel insights into the treatment of CRC.

Sodium selenite inhibits proliferation of lung cancer cells by inhibiting NF-κB nuclear translocation and down-regulating PDK1 expression which is a key enzyme in energy metabolism expression

As a trace element that maintains homeostasis in human body, selenium has significant anti-tumor activity. However, its exact molecular mechanism remains to be elucidated. Sodium selenite (SSe) is the most widely-distributed inorganic selenium in nature. In this study, we selected SSe as the research object to explore its anti-tumor mechanism in lung cancer. In vitro experiment showed that SSe could inhibit the activation of NF-κB signaling pathway, knowing that NF-κB is an important intracellular nuclear transcription factor that regulates the expression of pyruvate dehydrogenase kinase 1 (PDK1), a key energy metabolism switch affecting the survival status of the whole cell.At the same time, Bay11-7082(NF-κB signaling pathway inhibitors) and SSe resulted in phosphorylation of p65 and IκBα, decreased expression of PDK1 and Bcl-2,and increased expression of Bax in lung cancer cells. Our further study demonstrated that the reduction of PDK1 activity inhibited lactate secretion, reduced mitochondrial membrane potential, caused the release of Cytochrome C (Cyto C), activated mitochondrial respiration, and promoted the apoptosis of lung cancer cells. The in vivo experiment revealed that SSe inhibited the activation of NF-κB signaling pathway, decreased the expression of PDK1, and induced lung cancer cell proliferation and apoptosis. All these findings indicated that SSe promoted lung cancer cell apoptosis by inhibiting the activation of NF-κB signaling pathway, down-regulating PDK1 and activating mitochondrial apoptosis pathway.

Unravelling the Anticancer Mechanisms of Traditional Herbal Medicines with Metabolomics

Metabolite profiling of cancer cells presents many opportunities for anticancer drug discovery. The Chinese, Indian, and African flora, in particular, offers a diverse source of anticancer therapeutics as documented in traditional folklores. In-depth scientific information relating to mechanisms of action, quality control, and safety profile will promote their extensive usage in cancer therapy. Metabolomics may be a more holistic strategy to gain valuable insights into the anticancer mechanisms of action of plants but this has remained largely unexplored. This review, therefore, presents the available metabolomics studies on the anticancer effects of herbal medicines commonly used in Africa and Asia. In addition, we present some scientifically understudied ‘candidate plants’ for cancer metabolomics studies and highlight the relevance of metabolomics in addressing other challenges facing the drug development of anticancer herbs. Finally, we discussed the challenges of using metabolomics to uncover the underlying mechanisms of potential anticancer herbs and the progress made in this regard.

Targeting pyruvate dehydrogenase kinase signaling in the development of effective cancer therapy

Pyruvate is irreversibly decarboxylated to acetyl coenzyme A by mitochondrial pyruvate dehydrogenase complex (PDC). Decarboxylation of pyruvate is considered a crucial step in cell metabolism and energetics. The cancer cells prefer aerobic glycolysis rather than mitochondrial oxidation of pyruvate. This attribute of cancer cells allows them to sustain under indefinite proliferation and growth. Pyruvate dehydrogenase kinases (PDKs) play critical roles in many diseases because they regulate PDC activity. Recent findings suggest an altered metabolism of cancer cells is associated with impaired mitochondrial function due to PDC inhibition. PDKs inhibit the PDC activity via phosphorylation of the E1a subunit and subsequently cause a glycolytic shift. Thus, inhibition of PDK is an attractive strategy in anticancer therapy. This review highlights that PDC/PDK axis could be implicated in cancer's therapeutic management by developing potential small-molecule PDK inhibitors. In recent years, a dramatic increase in the targeting of the PDC/PDK axis for cancer treatment gained an attention from the scientific community. We further discuss breakthrough findings in the PDC-PDK axis. In addition, structural features, functional significance, mechanism of activation, involvement in various human pathologies, and expression of different forms of PDKs (PDK1-4) in different types of cancers are discussed in detail. We further emphasized the gene expression profiling of PDKs in cancer patients to prognosis and therapeutic manifestations. Additionally, inhibition of the PDK/PDC axis by small molecule inhibitors and natural compounds at different clinical evaluation stages has also been discussed comprehensively.

Inhibition of Jurkat T Cell Proliferation by Active Components of Rumex japonicus Roots Via Induced Mitochondrial Damage and Apoptosis Promotion

Rumex japonicus Houtt (RJH) is a valuable plant used in traditional medicine to treat several diseases, such as scabies and jaundice. In this study, Jurkat cell growth inhibitory extracts of R. japonicus roots were subjected to bioassay-guided fractionation, resulting in the isolation of three naphthalene derivatives (3-5) along with one anthraquinone (6) and two phenolic compounds (1 and 2). Among these compounds, 2-methoxystypandrone (5) exhibited potent anti-proliferative effects on Jurkat cells. Analysis by flow cytometry confirmed that 2-methoxystypandrone (5) could significantly reduce mitochondrial membrane potential and promote increased levels of mitochondrial reactive oxygen species (ROS), suggesting a strong mitochondrial depolarization effect. Real-time quantitative polymerase chain reaction (qPCR) analysis was also performed, and the results revealed that the accumulation of ROS was caused by reduced mRNA expression levels of heme oxygenase (HO-1), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). In addition, 2-methoxystypandrone (5) triggered strong apoptosis that was mediated by the arrest of the G0/G1 phase of the cell cycle. Furthermore, 2-methoxystypandrone (5) downregulated p-IκB-α, p-NF-κB p65, Bcl2, and Bcl-xl and upregulated BAX proteins. Taken together, these findings revealed that 2-methoxystypandrone (5) isolated from RJH could potentially serve as an early lead compound for leukemia treatment involving intracellular signaling by increasing mitochondrial ROS and exerting anti-proliferative effects.

Hemistepsin A suppresses colorectal cancer growth through inhibiting pyruvate dehydrogenase kinase activity

Most cancer cells primarily produce their energy through a high rate of glycolysis followed by lactic acid fermentation even in the presence of abundant oxygen. Pyruvate dehydrogenase kinase (PDK) 1, an enzyme responsible for aerobic glycolysis via phosphorylating and inactivating pyruvate dehydrogenase (PDH) complex, is commonly overexpressed in tumors and recognized as a therapeutic target in colorectal cancer. Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata Bunge (Compositae). Here, we report that HsA is a PDK1 inhibitor can reduce the growth of colorectal cancer and consequent activation of mitochondrial ROS-dependent apoptotic pathway both in vivo and in vitro. Computational simulation and biochemical assays showed that HsA directly binds to the lipoamide-binding site of PDK1, and subsequently inhibits the interaction of PDK1 with the E2 subunit of PDH complex. As a result of PDK1 inhibition, lactate production was decreased, but oxygen consumption was increased. Mitochondrial ROS levels and mitochondrial damage were also increased. Consistent with these observations, the apoptosis of colorectal cancer cells was promoted by HsA with enhanced activation of caspase-3 and -9. These results suggested that HsA might be a potential candidate for developing a novel anti-cancer drug through suppressing cancer metabolism.

Paeoniflorin elicits the anti-proliferative effects on glioma cell via targeting translocator protein 18 KDa

As a natural compound isolated from Paeoniae radix, Paeoniflorin (PF) has been shown the antitumor effects in various types of human cancers including glioma, which is one of the serious tumors in central nervous system. Translocator protein 18 KDa (TSPO) has been shown to be relevant to the glioma aetiology. However, the regulation of PF in TSPO and neurosteriods biosynthesis on glioma is still unclear. In the present study, the glioma cell (U87 and U251) were cultured and used to quantify the bindings of PF on TSPO. Results indicated that there was not significant different between IC50 of PF and TSPO ligand PK11195. Moreover, PF exerted the anti-proliferative effects in glioma cell with a dose dependent inhibition from 12.5 to 100 μM in vitro. Consistent with the effects of PK11195, lowered levels on progesterone, allopregnanolone, as well as TSPO mRNA were induced by PF (25 and 50 μM). Furthermore, a xenograft mouse model with U87 cell-derived was significant inhibited by PF treatment, as well as the PK11195 administration. These results demonstrate that PF exerts its antitumor effects associated with the TSPO and neurosteroids biosynthesis in glioma cells could be a promising therapeutic agent for glioma therapy.

Ilimaquinone Induces the Apoptotic Cell Death of Cancer Cells by Reducing Pyruvate Dehydrogenase Kinase 1 Activity

In cancer cells, aerobic glycolysis rather than oxidative phosphorylation (OxPhos) is generally preferred for the production of ATP. In many cancers, highly expressed pyruvate dehydrogenase kinase 1 (PDK1) reduces the activity of pyruvate dehydrogenase (PDH) by inducing the phosphorylation of its E1α subunit (PDHA1) and subsequently, shifts the energy metabolism from OxPhos to aerobic glycolysis. Thus, PDK1 has been regarded as a target for anticancer treatment. Here, we report that ilimaquinone (IQ), a sesquiterpene quinone isolated from the marine sponge Smenospongia cerebriformis, might be a novel PDK1 inhibitor. IQ decreased the cell viability of human and murine cancer cells, such as A549, DLD-1, RKO, and LLC cells. The phosphorylation of PDHA1, the substrate of PDK1, was reduced by IQ in the A549 cells. IQ decreased the levels of secretory lactate and increased oxygen consumption. The anticancer effect of IQ was markedly reduced in PDHA1-knockout cells. Computational simulation and biochemical assay revealed that IQ interfered with the ATP binding pocket of PDK1 without affecting the interaction of PDK1 and the E2 subunit of the PDH complex. In addition, similar to other pyruvate dehydrogenase kinase inhibitors, IQ induced the generation of mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in the A549 cells. The apoptotic cell death induced by IQ treatment was rescued in the presence of MitoTEMPO, a mitochondrial ROS inhibitor. In conclusion, we suggest that IQ might be a novel candidate for anticancer therapeutics that act via the inhibition of PDK1 activity.

Huzhangoside A Suppresses Tumor Growth through Inhibition of Pyruvate Dehydrogenase Kinase Activity

Aerobic glycolysis is one of the important metabolic characteristics of many malignant tumors. Pyruvate dehydrogenase kinase (PDHK) plays a key role in aerobic glycolysis by phosphorylating the E1α subunit of pyruvate dehydrogenase (PDH). Hence, PDHK has been recognized as a molecular target for cancer treatment. Here, we report that huzhangoside A (Hu.A), a triterpenoid glycoside compound isolated from several plants of the Anemone genus, acts as a novel PDHK inhibitor. Hu.A was found to decrease the cell viability of human breast cancer MDA-MB-231, hepatocellular carcinoma Hep3B, colon cancer HT-29, DLD-1, and murine lewis lung carcinoma LLC cell lines. The activity of PDHK1 was decreased by Hu.A in both in vitro assays and in vivo assays in DLD-1 cells. Hu.A significantly increased the oxygen consumption and decreased the secretory lactate levels in DLD-1 cells. In addition, Hu.A interacted with the ATP-binding pocket of PDHK1 without affecting the interaction of PDHK1 and pyruvate dehydrogenase complex (PDC) subunits. Furthermore, Hu.A significantly induced mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in DLD-1 cells. Consistently, when Hu.A was intraperitoneally injected into LLC allograft mice, the tumor growth was significantly decreased. In conclusion, Hu.A suppressed the growth of tumors in both in vitro and in vivo models via inhibition of PDHK activity.

Strategies for targeting energy metabolism in Kirsten rat sarcoma viral oncogene homolog -mutant colorectal cancer

Alterations in cellular energy metabolism play critical roles in colorectal cancer (CRC). These alterations, which correlate to KRAS mutations, have been identified as energy metabolism signatures. This review summarizes the relationship between colorectal tumors associated with mutated KRAS and energy metabolism, especially for the deregulated energy metabolism that affects tumor cell proliferation, invasion, and migration. Furthermore, this review will concentrate on the role of metabolic genes, factors and signaling pathways, which are coupled with the primary energy source connected with the KRAS mutation that induces metabolic alterations. Strategies for targeting energy metabolism in mutated KRAS CRC are also introduced. In conclusion, deregulated energy metabolism has a close relationship with KRAS mutations in colorectal tumors. Therefore, selective inhibitors, agents against metabolic targets or KRAS signaling, may be clinically useful for colorectal tumor treatment through a patient-personalized approach.

Strategies to target energy metabolism in consensus molecular subtype 3 along with Kirsten rat sarcoma viral oncogene homolog mutations for colorectal cancer therapy

Alterations in cellular energy metabolism play a critical role in colorectal cancer (CRC), which has been identified as the definition of consensus molecular subtypes (CMSs), and CMS3 tumors exhibit energy metabolism signatures along with Kirsten rat sarcoma viral oncogene homolog (KRAS)-activating mutations. This review summarizes the relationship between CMS3 tumors associated with mutated KRAS and energy metabolism in CRC, especially for the dysregulated energy metabolism that affects tumor cell proliferation, invasion, and migration. Furthermore, this review concentrates on the role of metabolic genes and factors and signaling pathways, which coupled with a primary energy source connected with the CMS3 associated with mutated KRAS, induce metabolic alterations. The strategies to target energy metabolism for the metabolic alterations in mutated KRAS CRC are also introduced. In conclusion, dysregulated energy metabolism has a close relationship with mutated KRAS in CMS3 tumors. Therefore, selective inhibitors or agents against metabolic targets or KRAS signaling may be clinically useful for CMS3 tumor treatment through a personalized approach for patients with cancer.