PDK2 induces cisplatin-resistance in lung adenocarcinoma via transcriptional regulation of CNNM3

Recent advances in pyruvate dehydrogenase kinase inhibitors: Structures, inhibitory mechanisms and biological activities

Metabolism is reprogrammed in a variety of cancer cells to ensure their rapid proliferation. Cancer cells prefer to utilize glycolysis to produce energy as well as to provide large amounts of precursors for their division. In this process, cancer cells inhibit the activity of pyruvate dehydrogenase complex (PDC) by upregulating the expression of pyruvate dehydrogenase kinases (PDKs). Inhibiting the activity of PDKs in cancer cells can effectively block this metabolic transition in cancer cells, while also activating mitochondrial oxidative metabolism and promoting apoptosis of cancer cells. To this day, the study of PDKs inhibitors has become one of the research hotspots in the field of medicinal chemistry. Novel structures targeting PDKs are constantly being discovered, and some inhibitors have entered the clinical research stage. Here, we reviewed the research progress of PDKs inhibitors in recent years and classified them according to the PDKs binding sites they acted on, aiming to summarize the structural characteristics of inhibitors acting on different binding sites and explore their clinical application value. Finally, the shortcomings of some PDKs inhibitors and the further development direction of PDKs inhibitors are discussed.

Baicalin and lung diseases

Studies focusing on natural products have been conducted worldwide, and the results suggest that their natural ingredients effectively treat a wide range of illnesses. Baicalin (BIA) is a glycoside derived from the flavonoid baicalein present in Scutellaria baicalensis of the Lamiaceae family. Interestingly, BIA has been shown to protect the lungs in several animal models used in numerous studies. Therefore, we fully analyzed the data of the studies that focused on BIA's lung protective function against various injuries and included them in this review. Interestingly, BIA exhibits promising effects against acute lung injury, lung fibrosis, pulmonary embolism, and lung remodelling associated with COPD, LPS, and paraquat insecticide. BAI exhibits anticancer activity against lung cancer. Additionally, BIA potently attenuates lung damage associated with infections. BIA primarily exerts its therapeutic effects by suppressing inflammation, oxidative stress immune response, and apoptosis pathways. Nrf2/HO-1, PI3K/Akt, NF-κB, STAT3, MAPKs, TLR4, and NLRP3 are important targets in the pulmonary therapeutic effects of BIA on different lung disease models. Consequently, we recommend using it in future potential clinical applications, its contribution to treatment guidelines, and translating its promising effects to clinical practice in lung diseases.

Mitochondrial-related genes PDK2, CHDH, and ALDH5A1 served as a diagnostic signature and correlated with immune cell infiltration in ulcerative colitis

We conducted an investigation to determine the potential of mitochondrial-related genes as diagnostic biomarkers in ulcerative colitis (UC), while also examining their association with immune cell infiltration. To achieve this, we acquired four datasets pertaining to UC, which included gene expression arrays and clinical data, from the GEO database. Subsequently, we selected three signature genes (PDK2, CHDH, and ALDH5A1) to construct a diagnostic model for UC. The nomogram and ROC curves exhibited exceptional diagnostic efficacy. Following this, quantitative real-time polymerase chain reaction and western blotting assays validated the decreased mRNA and protein expression of PDK2, CHDH, and ALDH5A1 in the model of UC cells and dextran sulfate sodium salt (DSS)-induced mice colitis tissues, aligning with the findings in the risk model. This investigation suggested a negative correlation between the expression of ALDH5A1, CHDH, and PDK2 and the infiltration of M1 macrophages. Then, immunofluorescence analysis confirmed the augmented expression of CD86 in the tissue of mice subjected to DSS, while a diminished expression of ALDH5A1, CHDH, and PDK2 was observed. Consequently, it can be inferred that targeting mitochondria-associated genes, namely PDK2, CHDH, and ALDH5A1, holds potential as a viable strategy for prognostic prediction and the implementation of immune therapy for UC.

Targeting the pyruvate dehydrogenase complex/pyruvate dehydrogenase kinase (PDC/PDK) axis to discover potent PDK inhibitors through structure-based virtual screening and pharmacological evaluation

Proliferating cancer cells are characterized by the Warburg effect, a metabolic alteration in which ATP is generated from cytoplasmic glycolysis instead of oxidative phosphorylation. The pyruvate dehydrogenase complex/pyruvate dehydrogenase kinase (PDC/PDK) axis plays a crucial role in this effect and has been identified as a potential target for anticancer drug development. Herein, we present the discovery and pharmacological evaluation of potent PDK inhibitors targeting the PDK/PDC axis. We successfully identified 6 compounds from a small molecule library through a structure-based virtual screening campaign and evaluated their enzymatic inhibitory potencies for PDK1-4. Our results indicated that compound 1 exhibited submicromolar inhibitory activities against PDK1-3 (IC50 = 109.3, 135.8, and 458.7 nM, respectively), but is insensitive to PDK4 (IC50 = 8.67 μM). Furthermore, compound 1 inhibited the proliferation of A549 cells with an EC50 value of 10.7 μM. In addition, compound 1 induced cell apoptosis, arrested the cell cycle at the S phase, and reduced cell invasion and migration, while showing low in vivo toxicity at a high dose. Based on these observations, it can be concluded that compound 1 is a promising anti-PDK1-3 lead that merits further investigation.

Autophagy and Glycometabolic Reprograming in the Malignant Progression of Lung Cancer: A Review

Lung cancer is one of the leading causes of cancer-related deaths worldwide. However, there are currently limited treatment options that are widely available to patients with advanced lung cancer, and further research is required to inhibit or reverse disease progression more effectively. In lung and other solid tumor cancers, autophagy and glycometabolic reprograming are critical regulators of malignant development, including proliferation, drug resistance, invasion, and metastasis. To provide a theoretical basis for therapeutic strategies targeting autophagy and glycometabolic reprograming to prevent lung cancer, we review how autophagy and glycometabolism are regulated in the malignant development of lung cancer based on research progress in other solid tumors.

PDK1- and PDK2-mediated metabolic reprogramming contributes to the TGFβ1-promoted stem-like properties in head and neck cancer

BACKGROUND

Resistance to chemotherapeutic drugs is a key factor for cancer recurrence and metastases in head and neck cancer (HNC). Cancer stem cells (CSCs) in tumors have self-renewal, differentiation, and higher drug resistance capabilities, resulting in a poor prognosis for patients. In glucose metabolism, pyruvate dehydrogenase kinase (PDK) inhibits pyruvate dehydrogenase and impedes pyruvate from being metabolized into acetyl-CoA and entering the tricarboxylic acid cycle to generate energy. Studies have reported that PDK1 and PDK2 inhibition suppresses the growth, motility, and drug resistance of cancer cells. Furthermore, while TGFβ1 levels are persistently elevated in HNC patients with poor prognosis, the role of PDK isoforms in the TGFβ1-promoted progression and stem-like properties of HNC is unclear.

METHODS

Levels of PDK1 and PDK2 were evaluated in HNC tissue microarrays by immunohistochemistry to explore potential clinical relevance. PDK1 and PDK2 were knocked down by the lentivirus shRNA system to investigate their role in TGFβ1-promoted tumor progression in vitro.

RESULTS

We found that PDK2 levels were increased in the later stage of HNC tissues compared to constant PDK1 expression. After PDK1 and PDK2 knockdown, we discovered increased ATP production and decreased lactate production in TGFβ1-treated and untreated HNC cells. However, only PDK2 silencing significantly inhibited the clonogenic ability of HNC cells. We subsequently found that TGFβ1-promoted migration and invasion capabilities were decreased in PDK1 and PDK2 knockdown cells. The tumor spheroid-forming capability, motility, CSC genes, and multidrug-resistant genes were downregulated in PDK1 and PDK2 silencing CSCs. PDK1 and PDK2 inhibition reversed cisplatin and gemcitabine resistance of CSCs, but not paclitaxel resistance.

CONCLUSION

The results demonstrated that the PDK1- and PDK2-mediated Warburg effect contributes to the TGFβ1-enhanced stemness properties of HNC. Therefore, PDK1 and PDK2 may serve as molecular targets for the combination therapy of HNC.

Retro-inversion follicle-stimulating hormone peptide-modified nanoparticles for delivery of PDK2 shRNA against chemoresistant ovarian cancer by switching glycolysis to oxidative phosphorylation

Background

Most ovarian cancers are diagnosed at advanced stages characterized by abdominal dissemination and frequently exhibit chemoresistance. Pyruvate dehydrogenase kinase 2 (PDK2) regulates the switch between glycolysis and oxidative phosphorylation and contributes to tumor progression and chemoresistance. Here, we investigated the effects of PDK2 blockade on metabolic reprogramming and cisplatin sensitivity and evaluated the in vivo antitumor effects of PDK2 shRNA in chemoresistant ovarian cancer using retro-inverso follicle-stimulating hormone peptide-modified nanoparticle as carriers.

Methods

The expression of PDK2 was detected by immunohistochemistry, Western blot and real-time PCR. Cell proliferation and apoptosis were detected using CCK-8 and flow cytometry. Cell migration was detected by Transwell assay. Seahorse Analyzer was used to evaluate metabolic changes. The cisplatin-resistant ovarian cancer cells A2780cp were used to establish the mouse model of peritoneal metastatic ovarian cancer.

Results

A higher expression level of PDK2 was observed in chemoresistant ovarian cancer tissues and cell lines and was associated with shorter progression-free survival. PDK2 knockdown inhibited proliferation and migration and promoted apoptosis of both cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. Cisplatin sensitivity was increased even in cisplatin-resistant ovarian cancer cells. Mechanistically, PDK2 knockdown resulted in an increased oxygen consumption rate and decreased extracellular acidification rate, along with reduced lactate production, increased PDHC activity and increased levels of electron transport chain complexes III and V. The metabolism switched from glycolysis to oxidative phosphorylation. Finally, to specifically and effectively deliver PDK2 shRNA in vivo, we formulated a targeted delivery system containing retro-inverso follicle-stimulating hormone peptide as a targeting moiety and polyethylene glycol–polyethylenimine copolymers as carriers. The nanoparticle complex significantly suppressed tumor growth and peritoneal metastasis of cisplatin-resistant ovarian cancer without obvious toxicities.

Conclusions

Our findings showed the link between metabolic reprogramming and chemoresistance in ovarian cancer and provided an effective targeting strategy for switching metabolic pathways in cancer therapy.

Circadian Clock Genes Act as Diagnostic and Prognostic Biomarkers of Glioma: Clinic Implications for Chronotherapy

Gliomas are the most common primary intracranial tumors and closely related to circadian clock. Due to the high mortality and morbidity of gliomas, exploring novel diagnostic and early prognostic markers is necessary. Circadian clock genes (CCGs) play important roles in regulating the daily oscillation of biological processes and the development of tumor. Therefore, we explored the influences that the oscillations of circadian clock genes (CCGs) on diagnosis and prognosis of gliomas using bioinformatics. In this work, we systematically analyzed the rhythmic expression of CCGs in brain and found that some CCGs had strong rhythmic expression; the expression levels were significantly different between day and night. Four CCGs (ARNTL, NPAS2, CRY2, and DBP) with rhythmic expression were not only identified as differentially expressed genes but also had significant independent prognostic ability in the overall survival of glioma patients and were highly correlated with glioma prognosis in COX analysis. Besides, we found that CCG-based predictive model demonstrated higher predictive accuracy than that of the traditional grade-based model; this new prediction model can greatly improve the accuracy of glioma prognosis. Importantly, based on the four CCGs’ circadian oscillations, we revealed that patients sampled at night had higher predictive ability. This may help detect glioma as early as possible, leading to early cancer intervention. In addition, we explored the mechanism of CCGs affecting the prognosis of glioma. CCGs regulated the cell cycle, DNA damage, Wnt, mTOR, and MAPK signaling pathways. In addition, it also affects prognosis through gene coexpression and immune infiltration. Importantly, ARNTL can rhythmically modulated the cellular sensitivity to clinic drugs, temozolomide. The optimal point of temozolomide administration should be when ARNTL expression is highest, that is, the effect is better at night. In summary, our study provided a basis for optimizing clinical dosing regimens and chronotherapy for glioma. The four key CCGs can serve as potential diagnostic and prognostic biomarkers for glioma patients, and ARNTL also has obvious advantages in the direction of glioma chronotherapy.

The novel circular RNA HIPK3 accelerates the proliferation and invasion of hepatocellular carcinoma cells by sponging the micro RNA-124 or micro RNA-506/pyruvate dehydrogenase kinase 2 axis

Circular RNAs (circRNAs) have been confirmed to be associated with the progression of various cancers, including hepatocellular carcinoma (HCC). However, the role and mechanism of circHIPK3 in HCC are still unclear. To investigate its function, circHIPK3 expression was first determined by RT–qPCR in HCC tissues or cells. Functionally, cell proliferation and invasion were investigated by CCK-8, EdU, or Transwell assays. In terms of understanding the mechanism, the interaction of the circRNA HIPK3/micro RNA 124 (miRNA 124) or micro RNA 506 (miRNA506) /PDK2 regulatory loop was verified by dual-luciferase reporter gene assay. In addition, a xenograft tumor model was established to confirm the impact of circHIPK3 on the growth of HCC cells in vivo. We found that circHIPK3 was upregulated in HCC patients and associated with clinical characteristics, while miR-124 and miR-506 were downregulated in HCC patients. Additionally, we proved that knock down of circHIPK3 remarkably suppressed the proliferation and invasion of HCC cells. Mechanistically, circHIPK3 directly bound to miR-124 or miR-506 and inhibited their expression, and PDK2 was a target gene of miR-124 or miR-506. Moreover, circHIPK3 overexpression reversed the inhibitory effect of miR-124 or miR-506 on HCC progression. miR-124 or miR-506 could also suppress tumorigenesis of HCC cells by PDK2. Furthermore, in vivo evidence confirmed that knock down of circHIPK3 inhibited tumor formation. We suggest that circHIPK3 can accelerate the proliferation and invasion of HCC cells by sponging miR-124 or miR-506 to upregulate PDK2, which is the underlying mechanism of circHIPK3-induced HCC progression.

Cisplatin-mediated activation of glucocorticoid receptor induces platinum resistance via MAST1

Agonists of glucocorticoid receptor (GR) are frequently given to cancer patients with platinum-containing chemotherapy to reduce inflammation, but how GR influences tumor growth in response to platinum-based chemotherapy such as cisplatin through inflammation-independent signaling remains largely unclear. Combined genomics and transcription factor profiling reveal that MAST1, a critical platinum resistance factor that reprograms the MAPK pathway, is upregulated upon cisplatin exposure through activated transcription factor GR. Mechanistically, cisplatin binds to C622 in GR and recruits GR to the nucleus for its activation, which induces MAST1 expression and consequently reactivates MEK signaling. GR nuclear translocation and MAST1 upregulation coordinately occur in patient tumors collected after platinum treatment, and align with patient treatment resistance. Co-treatment with dexamethasone and cisplatin restores cisplatin-resistant tumor growth, whereas addition of the MAST1 inhibitor lestaurtinib abrogates tumor growth while preserving the inhibitory effect of dexamethasone on inflammation in vivo. These findings not only provide insights into the underlying mechanism of GR in cisplatin resistance but also offer an effective alternative therapeutic strategy to improve the clinical outcome of patients receiving platinum-based chemotherapy with GR agonists.

A pharmacophore-based classification better predicts the outcomes of HER2-negative breast cancer patients receiving the anthracycline- and/or taxane-based neoadjuvant chemotherapy

AIMS

Prognosis of patients for human epidermal growth factor receptor 2 (HER2)-negative breast cancer post neoadjuvant chemotherapy is not well understood. The aim of this study was to develop a novel pharmacophore-based signature to better classify and predict the risk of HER2-negative patients after anthracycline-and/or taxane-based neoadjuvant chemotherapy (NACT).

MAIN METHODS

Anthracycline and taxane pharmacophore-based genes were obtained from PharmMapper. Drug-targeted genes (DTG) related clinical and bioinformatic analyses were undertaken in four GEO datasets.

KEY FINDINGS

We used 12 genes from the pharmacophore to develop a DTG score (DTG-S). The DTG-S classification exhibited significant prognostic ability with respect to disease free survival (DFS) for HER2-negative patients who receive at least one type of neoadjuvant chemotherapy that included anthracycline and/or taxane. DTG-S associated with a high predictive ability for pathological complete response (pCR) as well as for prognosis of breast cancer. Using the DTG-S classification in other prediction models may improve the reclassification accuracy for DFS. Combining the DTG-S with other clinicopathological factors may further improve its predictive ability of patients' outcomes. Gene ontology and KEGG pathway analysis showed that the biological processes of DTG-S high group were associated with the cell cycle, cell migration, and cell signal transduction pathways. Targeted drug analysis shows that some CDK inhibitors and PI3K-AKT pathway inhibitors may be useful for high DTG-S patients.

SIGNIFICANCE

The DTG-S classification adds prognostic and predictive information to classical parameters for HER2-negative patients who receive anthracycline-and/or taxane-based NACT, which could improve the patients' risk stratification and may help guide adjuvant treatment.

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.

Altered glycolysis results in drug-resistant in clinical tumor therapy

Cancer cells undergo metabolic reprogramming, including increased glucose metabolism, fatty acid synthesis and glutamine metabolic rates. These enhancements to three major metabolic pathways are closely associated with glycolysis, which is considered the central component of cancer cell metabolism. Increasing evidence suggests that dysfunctional glycolysis is commonly associated with drug resistance in cancer treatment, and aberrant glycolysis plays a significant role in drug-resistant cancer cells. Studies on the development of drugs targeting these abnormalities have led to improvements in the efficacy of tumor treatment. The present review discusses the changes in glycolysis targets that cause drug resistance in cancer cells, including hexokinase, pyruvate kinase, pyruvate dehydrogenase complex, glucose transporters, and lactate, as well the underlying molecular mechanisms and corresponding novel therapeutic strategies. In addition, the association between increased oxidative phosphorylation and drug resistance is introduced, which is caused by metabolic plasticity. Given that aberrant glycolysis has been identified as a common metabolic feature of drug-resistant tumor cells, targeting glycolysis may be a novel strategy to develop new drugs to benefit patients with drug-resistance.

Comprehensive Molecular and Cellular Characterization of Acute Kidney Injury Progression to Renal Fibrosis

Acute kidney injury (AKI) and chronic kidney disease (CKD) represent different stages of renal failure; thus, CKD can be regarded as a result of AKI deterioration. Previous studies have demonstrated that immune cell infiltration, oxidative stress, and metabolic mentalism can support renal fibrosis progression in AKI cases. However, the most important triggers and cell types involved in this pathological progression remain unclear. This study was conducted to shed light into the underlying cellular and molecular features of renal fibrosis progression through the analysis of three mouse whole kidney and one human single-cell RNA-sequencing datasets publicly available. According to the different causes of AKI (ischemia reperfusion injury [IRI] or cisplatin), the mouse samples were divided into the CIU [control-IRI-unilateral ureteral obstruction (UUO)] and CCU (control-cisplatin-UUO) groups. Comparisons between groups revealed eight different modules of differentially expressed genes (DEGs). A total of 1,214 genes showed the same expression pattern in both CIU and CCU groups; however, 1,816 and 1,308 genes were expressed specifically in the CCU and CIU groups, respectively. Further assessment of the DEGs according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway and Gene Ontology (GO) showed that T-cell activation, fatty acid metabolic process, and arachidonic acid metabolism were involved in the fibrosis progression in CIU and CCU. Single-cell RNA-sequencing data along with the collected DEGs information also revealed that the T-cell activation mainly happened in immune cells, whereas the fatty acid metabolic process and arachidonic acid metabolism occurred in tubule cells. Taken together, these findings suggest that the fibrosis process differed between the CIU and CCU stages, in which immune and tubule cells have different functions. These identified cellular and molecular features of the different stages of fibrosis progression may pave the way for exploring novel potential therapeutic strategies in the clinic.

Long noncoding RNA DUXAP8 contributes to the progression of hepatocellular carcinoma via regulating miR-422a/PDK2 axis

Background

Hepatocellular carcinoma (HCC) is one of the most deadly cancer worldwide. Multiple long noncoding RNAs (lncRNAs) are recently identified as crucial oncogenic factors or tumor suppressors. In this study, we explored the functon and mechanism of lncRNA double homeobox A pseudogene 8 (DUXAP8) in the progression of HCC.

Methods

Expression levels of DUXAP8 in HCC tissue samples were measured using qRT‐PCR. The association between pathological indexes and the expression of DUXAP8 was also analyzed. Human HCC cell lines SMMC‐7721 and QSG‐7701 were used in in vitro studies. CCK‐8 assay was used to assess the effect of DUXAP8 on HCC cell line proliferation. Scratch healing assay and Transwell assay were conducted to detect the effect of DUXAP8 on migration and invasion. Furthermore, dual‐luciferase reporter assay was used to confirm targeting relationship between miR‐422a and DUXAP8. Additionally, Western blot was used to detect the regulatory function of DUXAP8 on pyruvate dehydrogenase kinase 2 (PDK2).

Results

DUXAP8 expression HCC clinical samples was significantly increased and this was correlated with unfavorable pathological indexes. High expression of DUXAP8 was associated with shorter overall survival time of patients. Its overexpression remarkably facilitated the proliferation, metastasis, and epithelial‐mesenchymal transition of HCC cells. Accordingly, knockdown of it suppressed the malignant phenotypes of HCC cells. Overexpression of DUXAP8 significantly reduced the expression of miR‐422a by sponging it, but enhanced the expression of PDK2.

Conclusions

DUXAP8 was a sponge of tumor suppressor miR‐422a in HCC, enhanced the expression of PDK2 indirectly, and functioned as an oncogenic lncRNA.