Inhibiting 6-phosphogluconate dehydrogenase reverses doxorubicin resistance in anaplastic thyroid cancer via inhibiting NADPH-dependent metabolic reprogramming

The Emerging Roles of the Metabolic Regulator G6PD in Human Cancers

Metabolic reprogramming, especially reprogrammed glucose metabolism, is a well-known cancer hallmark related to various characteristics of tumor cells, including proliferation, survival, metastasis, and drug resistance. Glucose-6-phosphate dehydrogenase (G6PD) is the first and rate-limiting enzyme of the pentose phosphate pathway (PPP), a branch of glycolysis, that converts glucose-6-phosphate (G6P) into 6-phosphogluconolactone (6PGL). Furthermore, PPP produces ribose-5-phosphate (R5P), which provides sugar-phosphate backbones for nucleotide synthesis as well as nicotinamide adenine dinucleotide phosphate (NADPH), an important cellular reductant. Several studies have shown enhanced G6PD expression and PPP flux in various tumor cells, as well as their correlation with tumor progression through cancer hallmark regulation, especially reprogramming cellular metabolism, sustaining proliferative signaling, resisting cell death, and activating invasion and metastasis. Inhibiting G6PD could suppress tumor cell proliferation, promote cell death, reverse chemoresistance, and inhibit metastasis, suggesting the potential of G6PD as a target for anti-tumor therapeutic strategies. Indeed, while challenges-including side effects-still remain, small-molecule G6PD inhibitors showing potential anti-tumor effect either when used alone or in combination with other anti-tumor drugs have been developed. This review provides an overview of the structural significance of G6PD, its role in and regulation of tumor development and progression, and the strategies explored in relation to G6PD-targeted therapy.

The pentose phosphate pathway in health and disease

The pentose phosphate pathway (PPP) is a glucose-oxidizing pathway that runs in parallel to upper glycolysis to produce ribose 5-phosphate and nicotinamide adenine dinucleotide phosphate (NADPH). Ribose 5-phosphate is used for nucleotide synthesis, while NADPH is involved in redox homoeostasis as well as in promoting biosynthetic processes, such as the synthesis of tetrahydrofolate, deoxyribonucleotides, proline, fatty acids and cholesterol. Through NADPH, the PPP plays a critical role in suppressing oxidative stress, including in certain cancers, in which PPP inhibition may be therapeutically useful. Conversely, PPP-derived NADPH also supports purposeful cellular generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) for signalling and pathogen killing. Genetic deficiencies in the PPP occur relatively commonly in the committed pathway enzyme glucose-6-phosphate dehydrogenase (G6PD). G6PD deficiency typically manifests as haemolytic anaemia due to red cell oxidative damage but, in severe cases, also results in infections due to lack of leucocyte oxidative burst, highlighting the dual redox roles of the pathway in free radical production and detoxification. This Review discusses the PPP in mammals, covering its roles in biochemistry, physiology and disease.

6-Phosphogluconate dehydrogenase inhibition arrests growth and induces apoptosis in gastric cancer via AMPK activation and oxidative stress

Poor outcomes in advanced gastric cancer necessitate alternative therapeutic strategies. 6-Phosphogluconate dehydrogenase (6-PGDH), an enzyme that catalyzes the decarboxylation step in the oxidative pentose phosphate pathway, has been identified as a promising therapeutic target in many cancers. In this study, we systematically investigated the expression and function of 6-PGDH in gastric cancer. We found that 6-PGDH expression and activity were aberrantly elevated in gastric cancer tissues compared to their adjacent normal tissues. 6-PGDH knockdown using two independent shRNAs resulted in minimal 6-PGDH levels and activity, decreased growth, and enhanced gastric cancer cell sensitivity to 5-flurorouracil. However, 6-PGDH knockdown did not affect the cancer cells. Mechanistic studies showed that 6-PGDH inhibition disrupted lipid biosynthesis and redox homeostasis in gastric cancer, inhibited growth, and induced apoptosis. Notably, the in vitro findings were validated using an in vivo gastric cancer xenograft mouse model. This study established that 6-PGDH is broadly elevated in gastric cancer patients and that 6-PGDH inhibition can sensitize gastric cancer cells in response to chemotherapy.

Inhibition of 6-Phosphogluconate Dehydrogenase Reverses Epirubicin Resistance Through Metabolic Reprograming in Triple-Negative Breast Cancer Cells

At present, chemotherapy is the most effective strategy for treating triple-negative breast cancer (TNBC), but its efficacy was limited by the development of chemo-resistance. The exact mechanism of chemoresistance still remains unclear. This study aims to examine whether 6-phosphogluconate dehydrogenase (6PGD), a key enzyme in the oxidative pentose phosphate pathway (PPP), could promote the resistance of TNBC cells to epirubicin. A TNBC epirubicin-resistant cell line was developed by increasing concentration and the effectiveness was tested. The expression and knockdown efficiency of 6PGD were further validated by performing quantitative real-time PCR (qPCR) and Western blot. The effects of 6PGD on parental and drug-resistant TNBC cell lines were verified based on proliferation and apoptosis experiments. Finally, nicotinamide adenine dinucleotide phosphate (NADPH) and lactate quantitative experiments were performed to examine the mechanism of 6PGD in promoting drug resistance. Epirubicin-resistant cancer cells exhibited a higher level of 6PGD in contrast to epirubicin-sensitive cells. In addition, 6PGD inhibited by genetic and pharmacological approaches significantly suppressed the growth and survival of both epirubicin-sensitive and epirubicin-resisteant TNBC cells. It should be noted that 6PGD inhibition sensitized epirubicin-resistant TNBC cells to epirubicin treatment. Moreover, it was also found that the levels of NADPH and lactate increased in epirubicin-resistant TNBC cells but decreased in response to 6PGD inhibition. The present results indicated that 6PGD inhibition disrupted metabolic reprogramming in epirubicin-resistant TNBC cells. Our work demonstrated that 6PGD inhibition reversed the resistance of TNBC cells to epirubicin, providing an alternative therapeutic choice to tackle the challenge of epirubicin resistance in TNBC treatment.

Reprogramming of Cellular Metabolism and Its Therapeutic Applications in Thyroid Cancer

Metabolism is a series of life-sustaining chemical reactions in organisms, providing energy required for cellular processes and building blocks for cellular constituents of proteins, lipids, carbohydrates and nucleic acids. Cancer cells frequently reprogram their metabolic behaviors to adapt their rapid proliferation and altered tumor microenvironments. Not only aerobic glycolysis (also termed the Warburg effect) but also altered mitochondrial metabolism, amino acid metabolism and lipid metabolism play important roles for cancer growth and aggressiveness. Thus, the mechanistic elucidation of these metabolic changes is invaluable for understanding the pathogenesis of cancers and developing novel metabolism-targeted therapies. In this review article, we first provide an overview of essential metabolic mechanisms, and then summarize the recent findings of metabolic reprogramming and the recent reports of metabolism-targeted therapies for thyroid cancer.

Anticancer effects of natural phytochemicals in anaplastic thyroid cancer (Review)

Anaplastic thyroid cancer (ATC) is an aggressive and lethal malignancy having a dismal prognosis. Phytochemicals are bioactive components obtained from plants that have been proven useful to treat numerous diseases. Phytochemicals are also an important source of novel anticancer drugs and an important area of research due to the numerous available candidates that can potentially treat cancers. This review discusses naturally occurring phytochemicals and their derivatives that show promising anticancer effects in anaplastic thyroid cancer. Anticancer effects include cell growth inhibition, induction of apoptosis, promoting cell cycle arrest, suppressing angiogenesis, modulating autophagy, and increasing the production of reactive oxygen species. Phytochemicals are not only prospective candidates in the therapy of anaplastic thyroid cancer but also exhibit potential as adjuvants to improve the anticancer effects of other drugs. Although some phytochemicals have excellent anticancer properties, drug resistance observed during the use of resveratrol and artemisinin in different anaplastic thyroid cancer cell lines is still a problem. Anaplastic thyroid cancer cells have several biological, clinical, and drug-resistance features that differ from differentiated thyroid cancer cells. Phytochemicals such as resveratrol and quercetin exhibit different biological effects in anaplastic thyroid cancer and differentiated thyroid cancer. Tumor cells depend on increased aerobic glycolysis by mitochondrial oxidative phosphorylation to provide energy for their rapid growth, invasiveness, and drug resistance. Phytochemicals can alter signaling cascades, modulate the metabolic properties of cancer cells, and influence the mitochondrial membrane potential of anaplastic thyroid cancer cells. These findings enrich our knowledge of the anticancer effects of phytochemicals and highlight alternative therapies to prevent drug resistance in anaplastic thyroid cancer.

Are we still on the right path(way)?: the altered expression of the pentose phosphate pathway in solid tumors and the potential of its inhibition in combination therapy

INTRODUCTION

The pentose phosphate pathway (PPP) branches from glycolysis and is crucial for cell growth, since it provides necessary compounds for anabolic reactions, nucleotide synthesis, and detoxification of reactive-oxygen-species (ROS). Overexpression of PPP enzymes has been reported in multiple cancer types and linked to therapy resistance, making their inhibition interesting targets for anti-cancer therapies.

AREAS COVERED

This review summarizes the extent of PPP upregulation across different cancer types, and the non-metabolic functions that PPP-enzymes might contribute to cancer initiation and maintenance. The effects of PPP-inhibition and their combinations with chemotherapeutics are summarized. We searched the databases provided by the University of Amsterdam to characterize the altered expression of the PPP across different cancer types, and to identify the effects of PPP-inhibition.

EXPERT OPINION

It can be concluded that there are synergistic and additive effects of PPP-inhibition and various classes of chemotherapeutics. These effects may be attributed to the increased susceptibility to ROS. However, the toxicity, low efficacy, and off-target effects of PPP-inhibitors make application in clinical practice challenging. Novel inhibitors are currently being developed, which could make PPP-inhibition a potential therapeutic strategy in the future, especially in combination with conventional chemotherapeutics and the inhibition of other metabolic pathways.

Ferroptosis-related gene signature predicts the prognosis of papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer (TC), accounting for more than 80% of all cases. Ferroptosis is a novel iron-dependent and Reactive oxygen species (ROS) reliant type of cell death which is distinct from the apoptosis, necroptosis and pyroptosis. Considerable studies have demonstrated that ferroptosis is involved in the biological process of various cancers. However, the role of ferroptosis in PTC remains unclear. This study aims at exploring the expression of ferroptosis-related genes (FRG) and their prognostic values in PTC.

Methods

A ferroptosis-related gene signature was constructed using lasso regression analysis through the PTC datasets of the Cancer Genome Atlas (TCGA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to investigate the bioinformatics functions of significantly different genes (SDG) of ferroptosis. Additionally, the correlations of ferroptosis and immune cells were assessed through the single-sample gene set enrichment analysis (ssGSEA) and CIBERSORT database. Finally, SDG were test in clinical PTC specimens and normal thyroid tissues.

Results

LASSO regression model was utilized to establish a novel FRG signature with 10 genes (ANGPTL7, CDKN2A, DPP4, DRD4, ISCU, PGD, SRXN1, TF, TFRC, TXNRD1) to predicts the prognosis of PTC, and the patients were separated into high-risk and low-risk groups by the risk score. The high-risk group had poorer survival than the low-risk group (p < 0.001). Receiver operating characteristic (ROC) curve analysis confirmed the signature's predictive capacity. Multivariate regression analysis identified the prognostic signature-based risk score was an independent prognostic indicator for PTC. The functional roles of the DEGs in the TGCA PTC cohort were explored using GO enrichment and KEGG pathway analyses. Immune related analysis demonstrated that the most types of immune cells and immunological function in the high-risk group were significant different with those in the low-risk group. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) verified the SDG have differences in expression between tumor tissue and normal thyroid tissue. In addition, cell experiments were conducted to observe the changes in cell morphology and expression of signature’s genes with the influence of ferroptosis induced by sorafenib.

Conclusions

We identified differently expressed FRG that may involve in PTC. A ferroptosis-related gene signature has significant values in predicting the patients’ prognoses and targeting ferroptosis may be an alternative for PTC’s therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02389-7.

miR-381-3p attenuates doxorubicin resistance in human anaplastic thyroid carcinoma via targeting homeobox A9

Abnormal microRNA (miR) expression has frequently been reported to be implicated in cancer-related drug resistance. Herein, we planned to investigate whether miR-381-3p contributes to doxorubicin (DOX) resistance in anaplastic thyroid carcinoma (ATC). DOX-resistant ATC tissues and cell lines were prepared to detect miR-381-3p and homeobox A9 (HOXA9) expression. CCK8, transwell and TUNEL assays were performed to evaluate cell proliferation, migration and invasion, and apoptosis in in vitro experiments. HOXA9 expression is intensively expressed in ATC tissues compared with benign thyroid tissues. Compared with parental ATC cell lines, HOXA9 protein expression is significantly up-regulated in DOX-resistant SW1736 and CAL62 cells. The knockdown of HOXA9 leads to growth inhibition and apoptosis of DOX-resistant SW1736 and CAL62 cells. Our results also indicate a significant decrease in miR-381-3p expression levels in DOX-resistant ATC tissues and cell lines. miR-381-3p may function as a tumour suppressor to impede proliferation, migration and invasion and induce apoptosis of DOX-resistant SW1736 and CAL62 cells by inhibiting HOXA9 protein expression. Our results present a novel signalling axis miR-381-3p/HOXA9 that mediates DOX resistance in ATC. miR-381-3p and HOXA9 may be promising molecular targets for preventing ATC progression and drug resistance.

NADPH homeostasis in cancer: functions, mechanisms and therapeutic implications

Nicotinamide adenine dinucleotide phosphate (NADPH) is an essential electron donor in all organisms, and provides the reducing power for anabolic reactions and redox balance. NADPH homeostasis is regulated by varied signaling pathways and several metabolic enzymes that undergo adaptive alteration in cancer cells. The metabolic reprogramming of NADPH renders cancer cells both highly dependent on this metabolic network for antioxidant capacity and more susceptible to oxidative stress. Modulating the unique NADPH homeostasis of cancer cells might be an effective strategy to eliminate these cells. In this review, we summarize the current existing literatures on NADPH homeostasis, including its biological functions, regulatory mechanisms and the corresponding therapeutic interventions in human cancers, providing insights into therapeutic implications of targeting NADPH metabolism and the associated mechanism for cancer therapy.

Metabolic Constrains Rule Metastasis Progression

Metastasis formation accounts for the majority of tumor-associated deaths and consists of different steps, each of them being characterized by a distinctive adaptive phenotype of the cancer cells. Metabolic reprogramming represents one of the main adaptive phenotypes exploited by cancer cells during all the main steps of tumor and metastatic progression. In particular, the metabolism of cancer cells evolves profoundly through all the main phases of metastasis formation, namely the metastatic dissemination, the metastatic colonization of distant organs, the metastatic dormancy, and ultimately the outgrowth into macroscopic lesions. However, the metabolic reprogramming of metastasizing cancer cells has only recently become the subject of intense study. From a clinical point of view, the latter steps of the metastatic process are very important, because patients often undergo surgical removal of the primary tumor when cancer cells have already left the primary tumor site, even though distant metastases are not clinically detectable yet. In this scenario, to precisely elucidate if and how metabolic reprogramming drives acquisition of cancer-specific adaptive phenotypes might pave the way to new therapeutic strategies by combining chemotherapy with metabolic drugs for better cancer eradication. In this review we discuss the latest evidence that claim the importance of metabolic adaptation for cancer progression.

Discovery of Ebselen as an Inhibitor of 6PGD for Suppressing Tumor Growth

Introduction

The 6-phosphogluconate dehydrogenase (6PGD) was upregulated in many solid cancers and plays an important role in tumorigenesis. In the present study, we want to discover an old drug as an inhibitor of 6PGD for suppressing tumor growth.

Methods

We determined the expression of 6PGD in cancer tissues using Gene Expression Omnibus (GEO) profiles and explored the importance of 6PGD expression in cancer progression by using Kaplan–Meier Plotter. We identified Ebselen as a 6PGD inhibitor by using 6PGD in vitro enzyme activity assay. Cell viability, cell proliferation, tumor growth and cell metabolism assay were used to explore the role of 6PGD and its inhibitor in cancer cells.

Results

We found that the expression of 6PGD was upregulated in different cancer tissues and it can promote tumorigenesis. Here, we analyzed our 6PGD inhibitor screening data again and found an old drug Ebselen, which blocks cancer cell proliferation and tumor growth by inhibiting 6PGD enzyme activity, while knocking down 6PGD would partially abolish the inhibition of Ebselen on cell proliferation and cell metabolism.

Conclusion

Our results suggested that the conventional drug Ebselen could serve as a novel inhibitor of 6PGD for suppressing cancer growth by inhibiting 6PGD enzyme activity.

6-Phosphogluconate dehydrogenase fuels multiple aspects of cancer cells: From cancer initiation to metastasis and chemoresistance

Reprogrammed metabolism is key biochemical characteristic of malignant cells, which represents one of the emerging hallmarks of cancer. Currently, there is rising contemplation on oxidative pentose phosphate pathway (PPP) enzymes as potential therapeutic hits due to their affiliation with tumor metabolism. 6-Phosphogluconate dehydrogenase (6PGD), third oxidative decarboxylase of PPP, has received a great deal of attention during recent years due to its critical role in tumorigenesis and redox homeostasis. 6PGD has been reported to overexpress in number of cancer types and its hyperactivation is mediated through post-transcriptional and post-translational modifications by YTH domain family 2 (YTHDF2), Nrf2 (nuclear factor erythroid 2-related factor 2), EGFR (epidermal growth factor receptor) and via direct structural interactions with ME1 (malic enzyme 1). Upregulated expression of 6PGD provides metabolic as well as defensive advantage to cancer cells, thus, promoting their proliferative and metastatic potential. Moreover, enhanced 6PGD expression also performs key role in development of chemoresistance as well as radiation resistance in cancer. This review aims to discuss the historical timeline and cancer-specific role of 6PGD, pharmacological and genetic inhibitors of 6PGD and 6PGD as prognostic biomarker in order to explore its potential for therapeutic interventions. We anticipate that targeting this imperative supplier of NADPH might serve as tempting avenue to combat the deadly disease like cancer.

6PGD Upregulation is Associated with Chemo- and Immuno-Resistance of Renal Cell Carcinoma via AMPK Signaling-Dependent NADPH-Mediated Metabolic Reprograming

BACKGROUND

The essential role of 6-phosphogluconate dehydrogenase (6PGD), the enzyme catalyzing the oxidative pentose phosphate pathway, in tumor growth and metabolism has garnered attention in recent years. In this work, we are the first to demonstrate that aberrant activation of 6PGD is a feature in renal cell carcinoma (RCC) and is critically involved in renal carcinogenesis and chemo- and immuno-resistance.

MATERIALS AND METHODS

6PGD expression and activity were systematically analyzed in normal and malignant renal cells and tissues. The roles of 6PGD and its downstream mechanism were investigated using gain-of-function and loss-of-function approaches.

RESULTS

6PGD expression and enzyme activity were increased in RCC cells and patients' samples. Activation of 6PGD via gain-of-function approach promoted growth of normal kidney but not RCC cells, and alleviated the efficacy of chemotherapeutic (e.g., 5-FU) and immunotherapeutic (e.g., IFN-α) agents. In contrast, 6PGD inhibition using siRNA knockdown and pharmacological inhibitor physcion augmented the inhibitory effects of 5-FU and IFN-α in RCC. Mechanistic studies demonstrated that 6PGD inhibition activated AMPK signaling, leading to ACC1 enzyme inhibition and reduction of lipid synthesis. In addition, 6PGD inhibition disrupted NADPH and NADH homeostasis in RCC cells as shown by the decreased level of NADPH and NADH, and suppressed SIRT-1 activity. AMPK inhibition by siRNA knockdown reversed the inhibitory effects of physcion, demonstrating that the effect of 6PGD inhibition is AMPK activation dependent.

CONCLUSIONS

Our work provides preclinical evidence that 6PGD inhibition may represent a potential therapeutic strategy to augment the efficacy of RCC standard of care drugs.

Reactive Oxygen Species, Metabolic Plasticity, and Drug Resistance in Cancer

The metabolic abnormality observed in tumors is characterized by the dependence of cancer cells on glycolysis for their energy requirements. Cancer cells also exhibit a high level of reactive oxygen species (ROS), largely due to the alteration of cellular bioenergetics. A highly coordinated interplay between tumor energetics and ROS generates a powerful phenotype that provides the tumor cells with proliferative, antiapoptotic, and overall aggressive characteristics. In this review article, we summarize the literature on how ROS impacts energy metabolism by regulating key metabolic enzymes and how metabolic pathways e.g., glycolysis, PPP, and the TCA cycle reciprocally affect the generation and maintenance of ROS homeostasis. Lastly, we discuss how metabolic adaptation in cancer influences the tumor’s response to chemotherapeutic drugs. Though attempts of targeting tumor energetics have shown promising preclinical outcomes, the clinical benefits are yet to be fully achieved. A better understanding of the interaction between metabolic abnormalities and involvement of ROS under the chemo-induced stress will help develop new strategies and personalized approaches to improve the therapeutic efficiency in cancer patients.

Antimalarial drug artesunate is effective against chemoresistant anaplastic thyroid carcinoma via targeting mitochondrial metabolism

Anaplastic thyroid carcinoma (ATC) is the most aggressive type of thyroid malignancies and resistant to chemotherapy. Novel therapeutic strategy is required for better management of ATC. In this work, we show that artesunate, an antimalarial drug, is active against chemoresistant ATC cells. Artesunate dose-dependently inhibits growth and induces apoptosis in chemo-sensitive (8505C and KAT-4) and -resistant (8505C-r and KAT-4-r) ATC cells, and acts synergistically with doxorubicin. Using multiple xenograft mouse models, artesunate is active against chemo-sensitive and -resistant ATC cells in vivo at doses that do not cause toxicity in mice. Our mechanism analysis reveals that artesunate acts on ATC cells through suppressing mitochondrial functions without affecting glycolysis, leading to oxidative stress and damage, regardless of whether they are sensitive or resistant to chemotherapy. Interestingly, KAT-4-r cells demonstrate decreased glycolysis, increased mitochondrial membrane potential and mitochondrial respiration compared to KAT-4 cells whereas such phenomenon is not observed between 8505C and 8505C-r cells. This suggests that some but not all ATC cells gain enhanced mitochondrial biogenesis after prolonged exposure to chemotherapy drug, which may explain the different sensitivities of 8505C-r and KAT-4-r to artesunate. Our work demonstrates that artesunate is a potential addition to the treatment armamentarium for ATC, particularly those with chemoresistance. Our findings also highlight the therapeutic value of targeting mitochondria in chemoresistant ATC.

Nicotinic-nAChR signaling mediates drug resistance in lung cancer

Lung cancer is the leading cause of cancer death worldwide. Cigarette smoking is the most common risk factor for lung carcinoma; other risks include genetic factors and exposure to radon gas, asbestos, secondhand smoke, and air pollution. Nicotine, the primary addictive constituent of cigarettes, contributes to cancer progression through activation of nicotinic acetylcholine receptors (nAChRs), which are membrane ligand-gated ion channels. Activation of nicotine/nAChR signaling is associated with lung cancer risk and drug resistance. We focused on nAChR pathways activated by nicotine and its downstream signaling involved in regulating apoptotic factors of mitochondria and drug resistance in lung cancer. Increasing evidence suggests that several sirtuins play a critical role in multiple aspects of cancer drug resistance. Thus, understanding the consequences of crosstalk between nicotine/nAChRs and sirtuin signaling pathways in the regulation of drug resistance could be a critical implication for cancer therapy.

Salivary gland proteome analysis of developing adult female Haemaphysalis longicornis ticks: molecular motor and TCA cycle-related proteins play an important role throughout development

Background

Ticks are notorious blood-feeding arthropods that can spread a variety of deadly diseases. The salivary gland is an important organ for ticks to feed on blood, and this organ begins to develop rapidly when ixodid ticks suck blood. When these ticks reach a critical weight, the salivary glands stop developing and begin to degenerate. The expression levels of a large number of proteins during the development and degeneration of salivary glands change, which regulate the biological functions of the salivary glands. Furthermore, to the best of our knowledge, there are only a few reports on the role of molecular motor and TCA cycle-related proteins in the salivary glands of ticks.

Results

We used iTRAQ quantitative proteomics to study the dynamic changes in salivary gland proteins in female Haemaphysalis longicornis at four feeding stages: unfed, partially fed, semi-engorged and engorged. Using bioinformatics methods to analyze the dynamic changes of a large number of proteins, we found that molecular motor and TCA cycle-related proteins play an important role in the physiological changes of the salivary glands. The results of RNAi experiments showed that when dynein, kinesin, isocitrate dehydrogenase and citrate synthase were knocked down independently, the weight of the engorged female ticks decreased by 63.5%, 54.9%, 42.6% and 48.6%, respectively, and oviposition amounts decreased by 83.1%, 76.0%, 50.8%, and 55.9%, respectively, and the size of type III acini of females salivary glands decreased by 35.6%, 33.3%, 28.9%, and 20.0%, respectively.

Conclusions

The results showed that the expression of different types of proteins change in different characteristics in salivary glands during the unfed to engorged process of female ticks. Corresponding expression changes of these proteins at different developmental stages of female ticks are very important to ensure the orderly development of the organ. By analyzing these changes, some proteins, such as molecular motor and TCA cycle-related proteins, were screened and RNAi carried out. When these mRNAs were knocked down, the female ticks cannot develop normally. The research results provide a new protein target for the control of ticks and tick-borne diseases.

P-MAPA and IL-12 Differentially Regulate Proteins Associated with Ovarian Cancer Progression: A Proteomic Study

To investigate the potential role of immunotherapies in the cellular and molecular mechanisms associated with ovarian cancer (OC), we applied a comparative proteomic toll using protein identification combined with mass spectrometry. Herein, the effects of the protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride, known as P-MAPA, and the human recombinant interleukin-12 (hrIL-12) were tested alone or in combination in human SKOV-3 cells. The doses and period were defined based on a previous study, which showed that 25 μg/mL P-MAPA and 1 ng/mL IL-12 are sufficient to reduce cell metabolism after 48 h. Indeed, among 2,881 proteins modulated by the treatments, 532 of them were strictly concordant and common. P-MAPA therapy upregulated proteins involved in tight junction, focal adhesion, ribosome constitution, GTP hydrolysis, semaphorin interactions, and expression of SLIT and ROBO, whereas it downregulated ERBB4 signaling, toll-like receptor signaling, regulation of NOTCH 4, and the ubiquitin proteasome pathway. In addition, IL-12 therapy led to upregulation of leukocyte migration, tight junction, and cell signaling, while cell communication, cell metabolism, and Wnt signaling were significantly downregulated in OC cells. A clear majority of proteins that were overexpressed by the combination of P-MAPA with IL-12 are involved in tight junction, focal adhesion, DNA methylation, metabolism of RNA, and ribosomal function; only a small number of downregulated proteins were involved in cell signaling, energy and mitochondrial processes, cell oxidation and senescence, and Wnt signaling. These findings suggest that P-MAPA and IL-12 efficiently regulated important proteins associated with OC progression; these altered proteins may represent potential targets for OC treatment in addition to its immunoadjuvant effects.

Role of coenzymes in cancer metabolism

Cancer is a heterogeneous set of diseases characterized by the rewiring of cellular signaling and the reprogramming of metabolic pathways to sustain growth and proliferation. In past decades, studies were focused primarily on the genetic complexity of cancer. Recently, increasing number of studies have discovered several mutations among metabolic enzymes in different tumor cells. Most of the enzymes are regulated by coenzymes, organic cofactors, that function as intermediate carrier of electrons or functional groups that are transferred during the reaction. However, the precise role of cofactors is not well elucidated. In this review, we discuss several metabolic enzymes associated to cancer metabolism rewiring, whose inhibition may represent a therapeutic target. Such enzymes, upon expression or inhibition, may impact also the coenzymes levels, but only in few cases, it was possible to direct correlate coenzymes changes with a specific enzyme. In addition, we also summarize an up-to-date information on biological role of some coenzymes, preclinical and clinical studies, that have been carried out in various cancers and their outputs.

Cyanide and lactate levels in patients during chronic oral amygdalin intake followed by intravenous amygdalin administration

The natural compound amygdalin has gained high popularity among tumor patients as a complementary or alternative treatment option. However, due to metabolization of amygdalin to cyanide (HCN) following oral consumption, there could be a high risk of lactic acidosis caused by cyanide intoxication. The present retrospective study was undertaken to evaluate cyanide blood and lactate plasma levels of tumor patients (n = 55) before and after intravenous (i.v.) amygdalin infusion. All patients had also continuously ingested amygdalin tablets (3 x 500 mg/day), excepting on the days of i.v. administration. Each patient received one to five intravenous amygdalin treatments. The time period between each i.v. application ranged between 4-6 days. The initial i.v. dose was 6 mg (n = 28), 9 mg (n = 1), 15 mg (n = 1) or 18 mg (n = 25). The mean cyanide blood level before i.v. amygdalin administration was 34.74 μg/L, which increased significantly to a mean value of 66.20 μg/L after i. v. amygdalin application. In contrast, lactate decreased significantly from 1266 μmol/L pre-infusion to 868 μmol/L post-infusion. Increasing i.v. amygdalin by 1 mg was also associated with a significant increase in the cyanide level, while the lactate blood level significantly decreased. This is the first study evaluating cyanide levels under conditions employed by amygdalin administrators, i.e. after chronic oral amygdalin intake and then again after a closely subsequent intravenous amygdalin administration. Since lactate decreased, whilst cyanide increased, it is concluded that elevation of cyanide does not induce metabolic acidosis in terms of an increased lactate level.

The Influence of Metabolism on Drug Response in Cancer

Resistance to therapeutic agents, either intrinsic or acquired, is currently a major problem in the treatment of cancers and occurs in virtually every type of anti-cancer therapy. Therefore, understanding how resistance can be prevented, targeted and predicted becomes increasingly important to improve cancer therapy. In the last decade, it has become apparent that alterations in cellular metabolism are a hallmark of cancer cells and that a rewired metabolism is essential for rapid tumor growth and proliferation. Recently, metabolic alterations have been shown to play a role in the sensitivity of cancer cells to widely-used first-line chemotherapeutics. This suggests that metabolic pathways are important mediators of resistance toward anticancer agents. In this review, we highlight the metabolic alterations associated with resistance toward different anticancer agents and discuss how metabolism may be exploited to overcome drug resistance to classical chemotherapy.