Combined use of arginase and dichloroacetate exhibits anti-proliferative effects in triple negative breast cancer cells

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

Selective enhanced cytotoxicity of amino acid deprivation for cancer therapy using thermozyme functionalized nanocatalyst

BACKGROUND

Enzyme therapy based on differential metabolism of cancer cells has demonstrated promising potential as a treatment strategy. Nevertheless, the therapeutic benefit of reported enzyme drugs is compromised by their uncontrollable activity and weak stability. Additionally, thermozymes with high thermal-stability suffer from low catalytic activity at body temperature, preventing them from functioning independently.

RESULTS

Herein, we have developed a novel thermo-enzymatic regulation strategy for near-infrared (NIR)-triggered precise-catalyzed photothermal treatment of breast cancer. Our strategy enables efficient loading and delivery of thermozymes (newly screened therapeutic enzymes from thermophilic bacteria) via hyaluronic acid (HA)-coupled gold nanorods (GNRs). These nanocatalysts exhibit enhanced cellular endocytosis and rapid enzyme activity enhancement, while also providing biosafety with minimized toxic effects on untargeted sites due to temperature-isolated thermozyme activity. Locally-focused NIR lasers ensure effective activation of thermozymes to promote on-demand amino acid deprivation and photothermal therapy (PTT) of superficial tumors, triggering apoptosis, G1 phase cell cycle arrest, inhibiting migration and invasion, and potentiating photothermal sensitivity of malignancies.

CONCLUSIONS

This work establishes a precise, remotely controlled, non-invasive, efficient, and biosafe nanoplatform for accurate enzyme therapy, providing a rationale for promising personalized therapeutic strategies and offering new prospects for high-precision development of enzyme drugs.

Antiproliferative Modulation and Pro-Apoptotic Effect of BR2 Tumor-Penetrating Peptide Formulation 2-Aminoethyl Dihydrogen Phosphate in Triple-Negative Breast Cancer

Breast cancer is the most common cancer in women, the so-called "Triple-Negative Breast Cancer" (TNBC) subtype remaining the most challenging to treat, with low tumor-free survival and poor clinical evolution. Therefore, there is a clear medical need for innovative and more efficient treatment options for TNBC. The aim of the present study was to evaluate the potential therapeutic interest of the association of the tumor-penetrating BR2 peptide with monophosphoester 2-aminoethyl dihydrogen phosphate (2-AEH2P), a monophosphoester involved in cell membrane turnover, in TNBC. For that purpose, viability, migration, proliferative capacity, and gene expression analysis of proteins involved in the control of proliferation and apoptosis were evaluated upon treatment of an array of TNBC cells with the BR2 peptide and 2-AEH2P, either separately or combined. Our data showed that, while possessing limited single-agent activity, the 2-AEH2P+BR2 association promoted significant cytotoxicity in TNBC cells but not in normal cells, with reduced proliferative potential and inhibition of cell migration. Mechanically, the 2-AEH2P+BR2 combination promoted an increase in cells expressing p53 caspase 3 and caspase 8, a reduction in cells expressing tumor progression and metastasis markers such as VEGF and PCNA, as well as a reduction in mitochondrial electrical potential. Our results indicate that the combination of the BR2 peptide with 2-AEH2P+BR2 may represent a promising therapeutic strategy in TNBC with potential use in clinical settings.

Unlocking the Potential of Arginine Deprivation Therapy: Recent Breakthroughs and Promising Future for Cancer Treatment

Arginine is a semi-essential amino acid that supports protein synthesis to maintain cellular functions. Recent studies suggest that arginine also promotes wound healing, cell division, ammonia metabolism, immune system regulation, and hormone biosynthesis-all of which are critical for tumor growth. These discoveries, coupled with the understanding of cancer cell metabolic reprogramming, have led to renewed interest in arginine deprivation as a new anticancer therapy. Several arginine deprivation strategies have been developed and entered clinical trials. The main principle behind these therapies is that arginine auxotrophic tumors rely on external arginine sources for growth because they carry reduced key arginine-synthesizing enzymes such as argininosuccinate synthase 1 (ASS1) in the intracellular arginine cycle. To obtain anticancer effects, modified arginine-degrading enzymes, such as PEGylated recombinant human arginase 1 (rhArg1-PEG) and arginine deiminase (ADI-PEG 20), have been developed and shown to be safe and effective in clinical trials. They have been tried as a monotherapy or in combination with other existing therapies. This review discusses recent advances in arginine deprivation therapy, including the molecular basis of extracellular arginine degradation leading to tumor cell death, and how this approach could be a valuable addition to the current anticancer arsenal.

Disturbance of the Warburg effect by dichloroacetate and niclosamide suppresses the growth of different sub-types of malignant pleural mesothelioma in vitro and in vivo

Background: Inhalation of asbestos fibers is the most common cause of malignant pleural mesothelioma (MPM). In 2004, the United States Food and Drug Administration approved a combination of cisplatin with pemetrexed to treat unresectable MPM. Nonetheless novel treatment is urgently needed. The objective of this study is to report the combination effect of dichloroacetate (DCA) or niclosamide (Nic) Nic in MPM.

Materials and methods: The effect of a combination of DCA and Nic was studied using a panel of MPM cell lines (H28, MSTO-211H, H226, H2052, and H2452). Cell viability was monitored by MTT assay. Glycolysis, oxidative phosphorylation, glucose, glycogen, pyruvate, lactate, citrate, succinate and ATP levels were determined by corresponding ELISA. Apoptosis, mitochondrial transmembrane potential, cell cycle analysis, hydrogen peroxide and superoxide were investigated by flow cytometry. Cell migration and colony formation were investigated by transwell migration and colony formation assays respectively. The in vivo effect was confirmed using 211H and H226 nude mice xenograft models.

Results and conclusion: Cell viability was reduced. Disturbance of glycolysis and/or oxidative phosphorylation resulted in downregulation of glycogen, citrate and succinate. DCA and/or Nic increased apoptosis, mitochondrial transmembrane depolarization, G2/M arrest and reactive oxygen species. Moreover, DCA and/or Nic suppressed cell migration and colony formation. Furthermore, a better initial tumor suppressive effect was induced by the DCA/Nic combination compared with either drug alone in both 211H and H226 xenograft models. In H226 xenografts, DCA/Nic increased median survival of mice compared with single treatment. Single drug and/or a combination disturbed the Warburg effect and activated apoptosis, and inhibition of migration and proliferation in vivo. In conclusion, dichloroacetate and/or niclosamide showed a tumor suppressive effect in MPM in vitro and in vivo, partially mediated by disturbance of glycolysis/oxidative phosphorylation, apoptosis, ROS production, G2/M arrest, and suppression of migration and proliferation.

Looking for the Holy Grail—Drug Candidates for Glioblastoma Multiforme Chemotherapy

Glioblastoma multiforme (GBM) is the deadliest and the most heterogeneous brain cancer. The median survival time of GBM patients is approximately 8 to 15 months after initial diagnosis. GBM development is determined by numerous signaling pathways and is considered one of the most challenging and complicated-to-treat cancer types. Standard GBM therapy consist of surgery followed by radiotherapy or chemotherapy, and combined treatment. Current standard of care (SOC) does not offer a significant chance for GBM patients to combat cancer, and the selection of available drugs is limited. For almost 20 years, there has been only one drug, Temozolomide (TMZ), approved as a first-line GBM treatment. Due to the limited efficacy of TMZ and the high rate of resistant patients, the implementation of new chemotherapeutics is highly desired. However, due to the unique properties of GBM, many challenges still need to be overcome before reaching a ‘breakthrough’. This review article describes the most recent compounds introduced into clinical trials as drug candidates for GBM chemotherapy.

The Biological Fate of a Novel Anticancer Drug Candidate TNBG-5602: Metabolic Profile, Interaction with CYP450, and Pharmacokinetics in Rats

TNBG-5602, a novel anticancer drug candidate, may induce the expression of PPARγ, causing targeted lipotoxicity in cancer tissues. In this study, the in vivo metabolism in rats, in vitro metabolism in recombinant cytochromes, molecular docking for the CYP binding site, and pharmacokinetics in rats were explored to better understand TNBG-5602's in vivo fate and behavior. Thirteen metabolites were identified using a high-resolution mass spectrometry method, and metabolizing pathways of TNBG-5602 were proposed. Results suggest that TNBG-5602 could be metabolized by CYP450s, while CYP2D6 may play an important role in its in vivo metabolism. The main metabolizing sites of TNBG-5602 are the amino group on the side chain and rings A and E in the molecule. TNBG-5602 is a potent CYP2D6 inhibitor, with an IC₅₀ value of 2.52 μM. An interaction responsible for its metabolism is formed by the NH on the side chain bonding with the ASP301 on the CYP2D6. The pharmacokinetics in rats after a single intravenous administration were fitted to a two-compartment model. The clearance was 0.022 L min^-1, and the elimination half-life was 710.9 min. The distribution volume of the peripheral compartment was 1.88-fold that of the central compartment, while the K₁₂ was 1.5-fold that of K₂₁. In conclusion, these studies have not only revealed the metabolizing pathways of TNBG-5602 using in vivo and in vitro methodology, but they have also provided the pharmacokinetic characteristics of TNBG-5602 in rats. The results suggest that TNBG-5602 has good drug developability in terms of pharmacokinetic behaviors.

Are Pt(IV) Prodrugs That Release Combretastatin A4 True Multi-action Prodrugs?

"Multi-action" Pt(IV) derivatives of cisplatin with combretastatin A4 (CA4) bioactive ligands that are conjugated to Pt(IV) by carbonate are unique because the ligand (IC₅₀ < 10 nM) is dramatically 1000-folds more cytotoxic than cisplatin in vitro. The Pt(IV)-CA4 prodrugs were as cytotoxic as CA4 itself, indicating that the platinum moiety probably plays an insignificant role in triggering cytotoxicity, suggesting that the Pt(IV)-CA4 complexes act as prodrugs for CA4 rather than as true multi-action prodrugs. In vivo tests (Lewis lung carcinoma) show that ctc-[Pt(NH₃)₂(PhB)(CA4)Cl₂] inhibited tumor growth by 93% compared to CA4 (67%), cisplatin (84%), and 1:1:1 cisplatin/CA4/PhB (85%) while displaying <5% body weight loss compared to cisplatin (20%) or CA4 (10%). In this case, and perhaps with other extremely potent bioactive ligands, platinum(IV) acts merely as a self-immolative carrier triggered by reduction in the cancer cell with only a minor contribution to cytotoxicity.

Metabolic Response of Pancreatic Carcinoma Cells under Treatment with Dichloroacetate

In modern oncology, the analysis and evaluation of treatment response are still challenging. Hence, we used a ¹³C-guided approach to study the impacts of the small molecule dichloroacetate (DCA) upon the metabolic response of pancreatic cancer cells. Two different oncogenic PI3K-driven pancreatic cancer cell lines, 9580 and 10,158, respectively, were treated with 75 mM DCA for 18 h. In the presence of [U-¹³C₆]glucose, the effects of DCA treatment in the core carbon metabolism were analyzed in these cells using gas chromatography-mass spectrometry (GC/MS). ¹³C-enrichments and isotopologue profiles of key amino acids revealed considerable effects of the DCA treatment upon glucose metabolism. The DCA treatment of the two pancreatic cell lines resulted in a significantly decreased incorporation of [U-¹³C₆]glucose into the amino acids alanine, aspartate, glutamate, glycine, proline and serine in treated, but not in untreated, cancer cells. For both cell lines, the data indicated some activation of pyruvate dehydrogenase with increased carbon flux via the TCA cycle, but also massive inhibition of glycolytic flux and amino acid biosynthesis presumably by inhibition of the PI3K/Akt/mTORC axis. Together, it appears worthwhile to study the early treatment response in DCA-guided or accompanied cancer therapy in more detail, since it could open new avenues for improved diagnosis and therapeutic protocols of cancer.

Dichloroacetate attenuates the stemness of hepatocellular carcinoma cells via promoting nucleus-cytoplasm translocation of YAP

The antitumor effects of dichloroacetate (DCA) have been widely explored, however, its roles in hepatocellular carcinoma (HCC) progression are still unclear. In the current work, we found that DCA had little effects on HCC cell viability, but could attenuate the stemness of HCC cells, which is evident by decreasing the tumor sphere-formation ability, ALDH activity and the expression of stemness critical regulators. Mechanistic studies based on RNA-sequencing data showed that DCA activated the Hippo pathway. Furthermore, we indicated that DCA promoted the nucleus-cytoplasm translocation of YAP, but not TAZ, another critical executor of Hippo pathway. Moreover, suppressing of Hippo pathway using XMU-MP-1, an inhibitor of Hippo pathway, partially abrogated DCA-induced inhibitory effects on HCC cell stemness. This work suggests that DCA might be a potential inhibitor for HCC progression.

Dichloroacetate attenuates the stemness of colorectal cancer cells via trigerring ferroptosis through sequestering iron in lysosomes

Colorectal cancer stem cell (CSC) has been regarded to be the root of colorectal cancer progression. However, there is still no effective therapeutic method targeting colorectal CSC in clinical application. Here, we investigated the effects of dichloroacetate (DCA) on colorectal cancer cell stemness. We showed that DCA could reduce colorectal cancer cell stemness in a dose-dependent manner, which is evident by the decreased expression of stemness markers, tumor cell sphere-formation and cell migration ability. In addition, it was found that DCA trigerred the ferroptosis of colorectal CSC, which is characterized as the upregulation of iron concentration, lipid peroxides, and glutathione level, and decreased cell viability. Mechanistic studies demonstrated that DCA could sequester iron in lysosome and thus trigger ferroptosis, which is necessary for DCA-mediated attenuation on colorectal cancer cell stemness. Taken together, this work suggests that DCA might be a colorectal CSC-killer.

Cancer cell metabolism: Rewiring the mitochondrial hub

To adapt to tumoral environment conditions or even to escape chemotherapy, cells rapidly reprogram their metabolism to handle adversities and survive. Given the rapid rise of studies uncovering novel insights and therapeutic opportunities based on the role of mitochondria in tumor metabolic programing and therapeutics, this review summarizes most significant developments in the field. Taking in mind the key role of mitochondria on carcinogenesis and tumor progression due to their involvement on tumor plasticity, metabolic remodeling, and signaling re-wiring, those organelles are also potential therapeutic targets. Among other topics, we address the recent data intersecting mitochondria as of prognostic value and staging in cancer, by mitochondrial DNA (mtDNA) determination, and current inhibitors developments targeting mtDNA, OXPHOS machinery and metabolic pathways. We contribute for a holistic view of the role of mitochondria metabolism and directed therapeutics to understand tumor metabolism, to circumvent therapy resistance, and to control tumor development.

Targeting Glucose Metabolism to Overcome Resistance to Anticancer Chemotherapy in Breast Cancer

Breast cancer (BC) is the most prevalent cancer in women. BC is heterogeneous, with distinct phenotypical and morphological characteristics. These are based on their gene expression profiles, which divide BC into different subtypes, among which the triple-negative breast cancer (TNBC) subtype is the most aggressive one. The growing interest in tumor metabolism emphasizes the role of altered glucose metabolism in driving cancer progression, response to cancer treatment, and its distinct role in therapy resistance. Alterations in glucose metabolism are characterized by increased uptake of glucose, hyperactivated glycolysis, decreased oxidative phosphorylation (OXPHOS) component, and the accumulation of lactate. These deviations are attributed to the upregulation of key glycolytic enzymes and transporters of the glucose metabolic pathway. Key glycolytic enzymes such as hexokinase, lactate dehydrogenase, and enolase are upregulated, thereby conferring resistance towards drugs such as cisplatin, paclitaxel, tamoxifen, and doxorubicin. Besides, drug efflux and detoxification are two energy-dependent mechanisms contributing to resistance. The emergence of resistance to chemotherapy can occur at an early or later stage of the treatment, thus limiting the success and outcome of the therapy. Therefore, understanding the aberrant glucose metabolism in tumors and its link in conferring therapy resistance is essential. Using combinatory treatment with metabolic inhibitors, for example, 2-deoxy-D-glucose (2-DG) and metformin, showed promising results in countering therapy resistance. Newer drug designs such as drugs conjugated to sugars or peptides that utilize the enhanced expression of tumor cell glucose transporters offer selective and efficient drug delivery to cancer cells with less toxicity to healthy cells. Last but not least, naturally occurring compounds of plants defined as phytochemicals manifest a promising approach for the eradication of cancer cells via suppression of essential enzymes or other compartments associated with glycolysis. Their benefits for human health open new opportunities in therapeutic intervention, either alone or in combination with chemotherapeutic drugs. Importantly, phytochemicals as efficacious instruments of anticancer therapy can suppress events leading to chemoresistance of cancer cells. Here, we review the current knowledge of altered glucose metabolism in contributing to resistance to classical anticancer drugs in BC treatment and various ways to target the aberrant metabolism that will serve as a promising strategy for chemosensitizing tumors and overcoming resistance in BC.

Metabolic Plasticity of Tumor Cells: How They Do Adapt to Food Deprivation

Dysregulated metabolism is a key hallmark of cancer cells and an enticing target for cancer treatment. Since the last 10 years, research on cancer metabolism has moved from pathway attention to network consideration. This metabolic complexity continuously adapt to new constraints in the tumor microenvironment. In this review, we will highlight striking changes in cancer cell metabolism compared to normal cells. Understanding this tumor metabolic plasticity suggests potential new targets and innovative combinatorial treatments for fighting cancer.

Dichloroacetate (DCA) and Cancer: An Overview towards Clinical Applications

An extensive body of literature describes anticancer property of dichloroacetate (DCA), but its effective clinical administration in cancer therapy is still limited to clinical trials. The occurrence of side effects such as neurotoxicity as well as the suspicion of DCA carcinogenicity still restricts the clinical use of DCA. However, in the last years, the number of reports supporting DCA employment against cancer increased also because of the great interest in targeting metabolism of tumour cells. Dissecting DCA mechanism of action helped to understand the bases of its selective efficacy against cancer cells. A successful coadministration of DCA with conventional chemotherapy, radiotherapy, other drugs, or natural compounds has been tested in several cancer models. New drug delivery systems and multiaction compounds containing DCA and other drugs seem to ameliorate bioavailability and appear more efficient thanks to a synergistic action of multiple agents. The spread of reports supporting the efficiency of DCA in cancer therapy has prompted additional studies that let to find other potential molecular targets of DCA. Interestingly, DCA could significantly affect cancer stem cell fraction and contribute to cancer eradication. Collectively, these findings provide a strong rationale towards novel clinical translational studies of DCA in cancer therapy.

TNBG-5602, a novel derivative of quinoxaline, inhibits liver cancer growth via upregulating peroxisome proliferator-activated receptor γ in vitro and in vivo

Objectives

TNBG-5602 is a newly synthesized compound with an isoquinoline structure. In the present study, we demonstrated the anticancer effect of TNBG-5602 in in-vitro and in-vivo models and investigated its possible anticancer mechanism.

Methods

The antiproliferation effect of TNBG-5602 in vitro was evaluated in human liver cancer cell line QGY-7701. The acute toxicity of TNBG-5602 was evaluated in mice. The anticancer activity of TNBG-5602 in vivo was assessed in a xenograft model of human liver cancer cell line QGY-7701.

Key findings

The results of CCK-8 assay showed that TNBG-5602 can effectively inhibit the proliferation of liver cancer cells in vitro. The acute toxicity test in mice showed that the LD50 of TNBG-5602 was 172 mg/kg. In a xenograft liver cancer model, TNBG-5602 could remarkably inhibit the growth of tumours. During in-vitro and in-vivo studies, we noted that TNBG-5602 could induce lipid accumulation in cancer cells and tissues. Further study indicated that the anticancer effect of TNBG-5602 may be exerted through activating peroxisome proliferator-activated receptor γ (PPARγ) and downregulating proliferating cell nuclear antigen (PCNA).

Conclusions

Our results suggested that TNBG-5602 might exert potent anticancer activity through increasing the expression of PPARγ.

The Importance of Gender-Related Anticancer Research on Mitochondrial Regulator Sodium Dichloroacetate in Preclinical Studies In Vivo

Sodium dichloroacetate (DCA) is an investigational medicinal product which has a potential anticancer preparation as a metabolic regulator in cancer cells’ mitochondria. Inhibition of pyruvate dehydrogenase kinases by DCA keeps the pyruvate dehydrogenase complex in the active form, resulting in decreased lactic acid in the tumor microenvironment. This literature review displays the preclinical research data on DCA’s effects on the cell pyruvate dehydrogenase deficiency, pyruvate mitochondrial oxidative phosphorylation, reactive oxygen species generation, and the Na⁺–K⁺–2Cl⁻ cotransporter expression regulation in relation to gender. It presents DCA pharmacokinetics and the hepatocarcinogenic effect, and the safety data covers the DCA monotherapy efficacy for various human cancer xenografts in vivo in male and female animals. Preclinical cancer researchers report the synergistic effects of DCA combined with different drugs on cancer by reversing resistance to chemotherapy and promoting cell apoptosis. Researchers note that female and male animals differ in the mechanisms of cancerogenesis but often ignore studying DCA’s effects in relation to gender. Preclinical gender-related differences in DCA pharmacology, pharmacological mechanisms, and the elucidation of treatment efficacy in gonad hormone dependency could be relevant for individualized therapy approaches so that gender-related differences in treatment response and safety can be proposed.