New aspects of an old drug--diclofenac targets MYC and glucose metabolism in tumor cells

Inhibition of lactate dehydrogenase A by diclofenac sodium induces apoptosis in HeLa cells through activation of AMPK

Cancer cells exhibit a unique metabolic preference for the glycolytic pathway over oxidative phosphorylation for maintaining the tumor microenvironment. Lactate dehydrogenase A (LDHA) is a key enzyme that facilitates glycolysis by converting pyruvate to lactate and has been shown to be upregulated in multiple cancers due to the hypoxic tumor microenvironment. Diclofenac (DCF), a nonsteroidal anti-inflammatory drug, has been shown to exhibit anticancer effects by interfering with the glucose metabolism pathway. However, the specific targets of this drug remain unknown. Using in silico, biochemical, and biophysical studies, we show that DCF binds to LDHA adjacent to the substrate binding site and inhibits its activity in a dose-dependent and allosteric manner in HeLa cells. Thus, DCF inhibits the hypoxic microenvironment and induces apoptosis-mediated cell death. DCF failed to induce cytotoxicity in HeLa cells when LDHA was knocked down, confirming that DCF exerts its antimitotic effects via LDHA inhibition. DCF-induced LDHA inhibition alters pyruvate, lactate, NAD+, and ATP production in cells, and this could be a possible mechanism through which DCF inhibits glucose uptake in cancer cells. DCF-induced ATP deprivation leads to mitochondria-mediated oxidative stress, which results in DNA damage, lipid peroxidation, and apoptosis-mediated cell death. Reduction in intracellular ATP levels additionally activates the sensor kinase, adenosine monophosphate-activated protein kinase (AMPK), which further downregulates phosphorylated ribosomal S6 kinase (p-S6K), leading to apoptosis-mediated cell death. We find that in LDHA knocked down cells, intracellular ATP levels were depleted, resulting in the inhibition of p-S6K, suggesting the involvement of DCF-induced LDHA inhibition in the activation of the AMPK/S6K signaling pathway.

ATP Inhibition for Starvation/Mild Photothermal/Photodynamic Synergy Therapy Using Polypeptide Nanoparticles Conjugating 2-Deoxy-D-Glucose and Dye under NIR Phototheranostic Strategy

Rapid propagation of tumor cells requires plenty of energy, which is adenosine triphosphate (ATP) dependent. ATP inhibition in tumors not only results in the starvation of tumor cells but also down-regulation of the level of heat shock proteins (HSPs), which usually increase during traditional photothermal therapy (PTT), especially when the temperature is up 50 °C. 2-deoxy-D-glucose (2DG) is an anti-glycolytic reagent and can be used as an efficient agent for ATP inhibition in tumors. Compared with typical PTT, low-temperature mild photothermal therapy (MPTT) is receiving more and more attention because it avoids the high temperatures causing damage to the normal tissue, and the increase of HSPs which decrease PTT. Here, multifunctional polypeptide nanoparticles pDG@Ahx conjugating both a NIR probe Ahx-BDP and 2DG into the side chain of the amphiphilic polypeptide have been prepared. In vitro and in vivo studies reveal that the as-prepared nanoparticles achieve a synergistic effect of starvation/MPTT/PDT (photodynamic therapy), and it provides a new strategy to NIR-I/II fluorescence imaging-guided starvation/MPTT/PDT synergy therapy for tumors.

The Killer's Web: Interconnection between Inflammation, Epigenetics and Nutrition in Cancer

Inflammation is a key contributor to both the initiation and progression of tumors, and it can be triggered by genetic instability within tumors, as well as by lifestyle and dietary factors. The inflammatory response plays a critical role in the genetic and epigenetic reprogramming of tumor cells, as well as in the cells that comprise the tumor microenvironment. Cells in the microenvironment acquire a phenotype that promotes immune evasion, progression, and metastasis. We will review the mechanisms and pathways involved in the interaction between tumors, inflammation, and nutrition, the limitations of current therapies, and discuss potential future therapeutic approaches.

Exploring monocarboxylate transporter inhibition for cancer treatment

Cells are separated from the environment by a lipid bilayer membrane that is relatively impermeable to solutes. The transport of ions and small molecules across this membrane is an essential process in cell biology and metabolism. Monocarboxylate transporters (MCTs) belong to a vast family of solute carriers (SLCs) that facilitate the transport of certain hydrophylic small compounds through the bilipid cell membrane. The existence of 446 genes that code for SLCs is the best evidence of their importance. In-depth research on MCTs is quite recent and probably promoted by their role in cancer development and progression. Importantly, it has recently been realized that these transporters represent an interesting target for cancer treatment. The search for clinically useful monocarboxylate inhibitors is an even more recent field. There is limited pre-clinical and clinical experience with new inhibitors and their precise mechanism of action is still under investigation. What is common to all of them is the inhibition of lactate transport. This review discusses the structure and function of MCTs, their participation in cancer, and old and newly developed inhibitors. Some suggestions on how to improve their anticancer effects are also discussed.

The radiation- and chemo-sensitizing capacity of diclofenac can be predicted by a decreased lactate metabolism and stress response

BACKGROUND

An enhanced aerobic glycolysis ("Warburg effect") associated with an increase in lactic acid in the tumor microenvironment contributes to tumor aggressiveness and resistance to radiation and chemotherapy. We investigated the radiation- and chemo-sensitizing effects of the nonsteroidal anti-inflammatory drug (NSAID) diclofenac in different cancer cell types.

METHODS

The effects of a non-lethal concentration of diclofenac was investigated on c-MYC and Lactate Dehydrogenase (LDH) protein expression/activity and the Heat shock Protein (HSP)/stress response in human colorectal (LS174T, LoVo), lung (A549), breast (MDA-MB-231) and pancreatic (COLO357) carcinoma cells. Radiation- and chemo-sensitization of diclofenac was determined using clonogenic cell survival assays and a murine xenograft tumor model.

RESULTS

A non-lethal concentration of diclofenac decreases c-MYC protein expression and LDH activity, reduces cytosolic Heat Shock Factor 1 (HSF1), Hsp70 and Hsp27 levels and membrane Hsp70 positivity in LS174T and LoVo colorectal cancer cells, but not in A549 lung carcinoma cells, MDA-MB-231 breast cancer cells and COLO357 pancreatic adenocarcinoma cells. The impaired lactate metabolism and stress response in diclofenac-sensitive colorectal cancer cells was associated with a significantly increased sensitivity to radiation and 5Fluorouracil in vitro, and in a human colorectal cancer xenograft mouse model diclofenac causes radiosensitization.

CONCLUSION

These findings suggest that a decrease in the LDH activity and/or stress response upon diclofenac treatment predicts its radiation/chemo-sensitizing capacity.

Possible Participation of Adenine Nucleotide Translocase ANT1 in the Cytotoxic Action of Progestins, Glucocorticoids, and Diclofenac on Tumor Cells

A comparative analysis of the cytostatic effects of progestins (gestobutanoyl, megestrol acetate, amol, dienogest, and medroxyprogesterone acetate), glucocorticoids (hydrocortisone, dexamethasone), and diclofenac on tumor cells was carried out in order to confirm their in silico predicted probabilities experimentally. The results showed the different sensitivity of HeLa, MCF-7, Hep-2, K-562, and Wi-38 cell lines to progestins, glucocorticoids, and diclofenac. The minimum IC50 was found for progestin gestobutanoyl (GB) as 18 µM for HeLa cells, and varied from 31 to 38 µM for MCF-7, Hep-2, and K-562. Glucocorticoids and diclofenac were much less cytotoxic in the HeLa, MCF-7, and Hep-2 cell lines than progestins, with IC50 values in the range of 150-3000 μM. Myelogenous leukemia K-562 cells were the least sensitive to the action of progestins and glucocorticoids but the most sensitive to diclofenac, which showed a pronounced cytotoxic effect with an IC50 of 31 μM. As we have shown earlier, progestins can uniquely modulate MPTP opening via the binding of adenine nucleotide translocase. On this basis, we evaluated the expression of adenylate nucleotide translocase ANT1 (SLC25 A4) as a possible participant in cytotoxic action in these cell lines after 48 h incubation with drugs. The results showed that progestins differently regulated ANT1 expression in different cell lines. Gestobutanoyl had the opposite effect on ANT1 expression in the HeLa, K562, and Wi-38 cells compared with the other progestins. It increased the ANT1 expression more than twofold in the HeLa and K562 cells but had no influence on the Wi-38 cells. Glucocorticoids and diclofenac increased ANT1 expression in the Wi-38 cells and decreased it in the K562, MCF-7, and Hep-2 cells. The modulation of ANT1 expression discovered in our study can be a new explanation of the cytotoxic and cytoprotective effects of hormones, which can vary depending on the cell type. ANT isoforms in normal and cancerous cells could be a new target for steroid hormone and anti-inflammatory drug action.

The Potential Preventive and Therapeutic Roles of NSAIDs in Prostate Cancer

Prostate cancer (PC) is the second most common type of cancer and the leading cause of death among men worldwide. Preventing the progression of cancer after treatments such as radical prostatectomy, radiation therapy, and hormone therapy is a major concern faced by prostate cancer patients. Inflammation, which can be caused by various factors such as infections, the microbiome, obesity and a high-fat diet, is considered to be the main cause of PC. Inflammatory cells are believed to play a crucial role in tumor progression. Therefore, nonsteroidal anti-inflammatory drugs along with their effects on the treatment of inflammation-related diseases, can prevent cancer and its progression by suppressing various inflammatory pathways. Recent evidence shows that nonsteroidal anti-inflammatory drugs are effective in the prevention and treatment of prostate cancer. In this review, we discuss the different pathways through which these drugs exert their potential preventive and therapeutic effects on prostate cancer.

Tumor microenvironment heterogeneity in bladder cancer identifies biologically distinct subtypes predicting prognosis and anti-PD-L1 responses

Bladder cancer (BCa) is heterogeneous in the tumour microenvironment (TME). However, the role of the TME in BCa in modulating the response to immunotherapy has not been fully explored. We therefore analysed fractions of immune cells using CIBERSORTx and clustered BCa into subtypes. We also analyzed weighted correlation networks to generate immunotherapy-related hub genes that we used to construct a prediction model using multivariate Cox and LASSO regression analyses. We found that BCa comprised three subtypes (C1‒C3). The prognosis of the patients was the most favourable and the response rate to anti-programmed death ligand 1 (PD-L1) was the highest in C1 among the three subtypes. Immune cells, including CD8+, CD4+ memory activated, and follicular helper T cells, activated NK cells, and M1 macrophages infiltrated the C1 subtype. The C2 subtype was enriched in M0 macrophages and activated mast cells, and the C3 subtype was enriched in B and resting immune cells. Mechanistically, the enhanced immunogenicity of subtypes C1 and C2 correlated positively with a higher response rate, whereas the dysregulated ECM-related pathways in the C2 subtype and glycolytic and fatty acid metabolic pathways in the C3 subtype impaired the responses of patients to anti-PD-L1 therapy. We also constructed a TME-related signature based on 18 genes that performed well in terms of overall survival. In conclusion, we determined prognoses and anti-PD-L1 responses by analysing TME heterogeneity in BCa.

Diclofenac and metformin synergistic dose dependent inhibition of hamster fibrosarcoma, rescued with mebendazole

We examined whether combinig diclofenac and metformin in doses equivalent to human doses would synergize their anticancer activity on fibrosarcoma inoculated to hamsters and in vitro. Rescue experiment was performed to examine whether the prosurvival NF-κB stimulation by mebendazole can reverse anticancer effects of the treatment. BHK-21/C13 cell culture was subcutaneously inoculated to Syrian golden hamsters randomly divided into groups (6 animals per group): 1) untreated control; treated daily with 2) diclofenac; 3) metformin; 4) combinations of diclofenac and metformin at various doses; 5) combination of diclofenac, metformin and mebendazole; 6) mebendazole. Dose response curves were made for diclofenac and metformin combination. Tumor growth kinetics, biophysical, pathological, histological and immunohistochemical characteristics of excised tumors and hamster organs as well as biochemical and hematological blood tests were compared among the groups. Single treatments had no anticancer effects. Diclofenac (60 mg/kg/day) exhibited significant (P < 0.05) synergistic inhibitory effect with metformin (500 mg/kg/day) on all tumor growth parameters, without toxicity and influence on biochemical and hematological blood tests. The same results were obtained with double doses of diclofenac and metformin combination. The addition of mebendazole to the diclofenac and metformin combination rescued tumor expansion. Furthermore, diclofenac with metformin demonstrated antiproliferative effects in hamster fibrosarcoma BHK-21/C13, human lung carcinoma A549 (CCL-185), colon carcinoma HT-29 (HTB-38) and cervical carcinoma HeLa (CCL-2) cell cultures, with markedly lower cytotoxicity in the normal fetal lung MRC-5 cells. In conclusion, diclofenac and metformin combination may be recommended for potential use in oncology, due to synergistic anticancer effect in doses achievable in humans.

Regulating tumor glycometabolism and the immune microenvironment by inhibiting lactate dehydrogenase with platinum(iv) complexes

Lactate dehydrogenase (LDH) is a key enzyme involved in the process of glycolysis, assisting cancer cells to take in glucose and generate lactate, as well as to suppress and evade the immune system by altering the tumor microenvironment (TME). Platinum(iv) complexes MDP and DDP were prepared by modifying cisplatin with diclofenac at the axial position(s). These complexes exhibited potent antiproliferative activity against a panel of human cancer cell lines. In particular, DDP downregulated the expression of LDHA, LDHB, and MCTs to inhibit the production and influx/efflux of lactate in cancer cells, impeding both glycolysis and glucose oxidation. MDP and DDP also reduced the expression of HIF-1α, ARG1 and VEGF, thereby disrupting the formation of tumor vasculature. Furthermore, they promoted the repolarization of macrophages from the tumor-supportive M2 phenotype to the tumor-suppressive M1 phenotype in the TME, thus enhancing the antitumor immune response. The antitumor mechanism involves reprogramming the energy metabolism of tumor cells and relieving the immunosuppressive TME.

Targeting metabolism by B-raf inhibitors and diclofenac restrains the viability of BRAF-mutated thyroid carcinomas with Hif-1α-mediated glycolytic phenotype

BACKGROUND

B-raf inhibitors (BRAFi) are effective for BRAF-mutated papillary (PTC) and anaplastic (ATC) thyroid carcinomas, although acquired resistance impairs tumour cells' sensitivity and/or limits drug efficacy. Targeting metabolic vulnerabilities is emerging as powerful approach in cancer.

METHODS

In silico analyses identified metabolic gene signatures and Hif-1α as glycolysis regulator in PTC. BRAF-mutated PTC, ATC and control thyroid cell lines were exposed to HIF1A siRNAs or chemical/drug treatments (CoCl2, EGF, HGF, BRAFi, MEKi and diclofenac). Genes/proteins expression, glucose uptake, lactate quantification and viability assays were used to investigate the metabolic vulnerability of BRAF-mutated cells.

RESULTS

A specific metabolic gene signature was identified as a hallmark of BRAF-mutated tumours, which display a glycolytic phenotype, characterised by enhanced glucose uptake, lactate efflux and increased expression of Hif-1α-modulated glycolytic genes. Indeed, Hif-1α stabilisation counteracts the inhibitory effects of BRAFi on these genes and on cell viability. Interestingly, targeting metabolic routes with BRAFi and diclofenac combination we could restrain the glycolytic phenotype and synergistically reduce tumour cells' viability.

CONCLUSION

The identification of a metabolic vulnerability of BRAF-mutated carcinomas and the capacity BRAFi and diclofenac combination to target metabolism open new therapeutic perspectives in maximising drug efficacy and reducing the onset of secondary resistance and drug-related toxicity.

Platinum(IV) Derivatives of [Pt(1S,2S-diaminocyclohexane)(5,6-dimethyl-1,10-phenanthroline)] with Diclofenac Ligands in the Axial Positions: A New Class of Potent Multi-action Agents Exhibiting Selectivity to Cancer Cells

The platinum(II) complex [Pt(1S,2S-diaminocyclohexane)(5,6-dimethyl-1,10-phenanthroline)]²⁺ (Pt^II56MeSS, 1) exhibits high potency across numerous cancer cell lines acting by a multimodal mechanism. However, 1 also displays side toxicity and in vivo activity; all details of its mechanism of action are not entirely clear. Here, we describe the synthesis and biological properties of new platinum(IV) prodrugs that combine 1 with one or two axially coordinated molecules of diclofenac (DCF), a non-steroidal anti-inflammatory cancer-selective drug. The results suggest that these Pt(IV) complexes exhibit mechanisms of action typical for Pt(II) complex 1 and DCF, simultaneously. The presence of DCF ligand(s) in the Pt(IV) complexes promotes the antiproliferative activity and selectivity of 1 by inhibiting lactate transporters, resulting in blockage of the glycolytic process and impairment of mitochondrial potential. Additionally, the investigated Pt(IV) complexes selectively induce cell death in cancer cells, and the Pt(IV) complexes containing DCF ligands induce hallmarks of immunogenic cell death in cancer cells.

Inhibition of lactate transport by MCT-1 blockade improves chimeric antigen receptor T-cell therapy against B-cell malignancies

BACKGROUND

Chimeric antigen receptor (CAR) T cells have shown remarkable results against B-cell malignancies, but only a minority of patients have long-term remission. The metabolic requirements of both tumor cells and activated T cells result in production of lactate. The export of lactate is facilitated by expression of monocarboxylate transporter (MCTs). CAR T cells express high levels of MCT-1 and MCT-4 on activation, while certain tumors predominantly express MCT-1.

METHODS

Here, we studied the combination of CD19-specific CAR T-cell therapy with pharmacological blockade of MCT-1 against B-cell lymphoma.

RESULTS

MCT-1 inhibition with small molecules AZD3965 or AR-C155858 induced CAR T-cell metabolic rewiring but their effector function and phenotype remained unchanged, suggesting CAR T cells are insensitive to MCT-1 inhibition. Moreover, improved cytotoxicity in vitro and antitumoral control on mouse models was found with the combination of CAR T cells and MCT-1 blockade.

CONCLUSION

This work highlights the potential of selective targeting of lactate metabolism via MCT-1 in combination with CAR T cells therapies against B-cell malignancies.

Multi-action platinum(IV) prodrugs conjugated with COX-inhibiting NSAIDs

In the last decades, inflammation has been recognized as being closely connected to cancer, and joint strategies encompassing chemotherapeutic and anti-inflammatory agents have been extensively studied. In this work, a series of novel cisplatin and oxaliplatin-based Pt(IV) complexes comprising non-steroidal anti-inflammatory drugs (NSAIDs) and their carboxyl ester analogues as axial moieties were synthesized. Several of the cisplatin-based Pt(IV) complexes 22-30 showed increased cytotoxicity in the human cancer cell lines CH1/PA-1, SW480 and A549 compared to the Pt(II) drug. For the most potent complex 26, comprising two aceclofenac (AFC) moieties, the formation of Pt(II)-9-methylguanine (9-MeG) adducts after activation with ascorbic acid (AsA) was proven. Additionally, a significant inhibition of cyclooxygenase (COX) activity and prostaglandin E₂ (PGE₂) production was observed, as well as increased cellular accumulation, depolarization of mitochondrial membranes, and strong proapoptotic potencies in SW480 cells. Overall, these systematic effects shown in vitro confer 26 as a potential anticancer agent combined with anti-inflammatory properties.

Perspectives of the Application of Non-Steroidal Anti-Inflammatory Drugs in Cancer Therapy: Attempts to Overcome Their Unfavorable Side Effects

Non-steroidal anti-inflammatory drugs (NSAIDs) express anti-tumoral activity mainly by blocking cyclooxygenase-2 involved in the synthesis of prostaglandins. Therefore, in the last few decades, many have attempted to explore the possibilities of applying this group of drugs as effective agents for the inhibition of neoplastic processes. This review summarizes the evidence presented in the literature regarding the anti-tumoral actions of NSAIDs used as monotherapies as well as in combination with conventional chemotherapeutics and natural products. In several clinical trials, it was proven that combinations of NSAIDs and chemotherapeutic drugs (CTDs) were able to obtain suitable results. The combination with phospholipids may resolve the adverse effects of NSAIDs and deliver derivatives with increased antitumor activity, whereas hybrids with terpenoids exhibit superior activity against their parent drugs or physical mixtures. Therefore, the application of NSAIDs in cancer therapy seems to be still an open chapter and requires deep and careful evaluation. The literature's data indicate the possibilities of re-purposing anti-inflammatory drugs currently approved for cancer treatments.

Manipulating T-cell metabolism to enhance immunotherapy in solid tumor

Cellular metabolism is not only essential for tumor cells to sustain their rapid growth and proliferation, but also crucial to maintain T cell fitness and robust immunity. Dysregulated metabolism has been recognized as a hallmark of cancer, which provides survival advantages for tumor cells under stress conditions. Also, emerging evidence suggests that metabolic reprogramming impacts the activation, differentiation, function, and exhaustion of T cells. Normal stimulation of resting T cells promotes the conversion of catabolic and oxidative metabolism to aerobic glycolysis in effector T cells, and subsequently back to oxidative metabolism in memory T cells. These metabolic transitions profoundly affect the trajectories of T-cell differentiation and fate. However, these metabolic events of T cells could be dysregulated by their interplays with tumor or the tumor microenvironment (TME). Importantly, metabolic competition in the tumor ecosystem is a new mechanism resulting in strong suppression of effector T cells. It is appreciated that targeting metabolic reprogramming is a promising way to disrupt the hypermetabolic state of tumor cells and enhance the capacity of immune cells to obtain nutrients. Furthermore, immunotherapies, such as immune checkpoint inhibitor (ICI), adoptive cell therapy (ACT), and oncolytic virus (OV) therapy, have significantly refashioned the clinical management of solid tumors, they are not sufficiently effective for all patients. Understanding how immunotherapy affects T cell metabolism provides a bright avenue to better modulate T cell anti-tumor response. In this review, we provide an overview of the cellular metabolism of tumor and T cells, provide evidence on their dynamic interaction, highlight how metabolic reprogramming of tumor and T cells regulate the anti-tumor responses, describe T cell metabolic patterns in the context of ICI, ACT, and OV, and propose hypothetical combination strategies to favor potent T cell functionality.

Targeted nanomedicines remodeling immunosuppressive tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has significantly flourished and revolutionized the limited conventional tumor therapies, on account of its good safety and long-term memory ability. Discouragingly, low patient response rates and potential immune-related side effects make it rather challenging to literally bring immunotherapy from bench to bedside. However, it has become evident that, although the immunosuppressive tumor microenvironment (TME) plays a pivotal role in facilitating tumor progression and metastasis, it also provides various potential targets for remodeling the immunosuppressive TME, which can consequently bolster the effectiveness of antitumor response and tumor suppression. Additionally, the particular characteristics of TME, in turn, can be exploited as avenues for designing diverse precise targeting nanomedicines. In general, it is of urgent necessity to deliver nanomedicines for remodeling the immunosuppressive TME, thus improving the therapeutic outcomes and clinical translation prospects of immunotherapy. Herein, we will illustrate several formation mechanisms of immunosuppressive TME. More importantly, a variety of strategies concerning remodeling immunosuppressive TME and strengthening patients' immune systems, will be reviewed. Ultimately, we will discuss the existing obstacles and future perspectives in the development of antitumor immunotherapy. Hopefully, the thriving bloom of immunotherapy will bring vibrancy to further exploration of comprehensive cancer treatment.

Development and Challenges of Diclofenac-Based Novel Therapeutics: Targeting Cancer and Complex Diseases

Simple Summary

Diclofenac is a widely used drug for its anti-inflammatory and pain alleviating properties. This review summarizes the current understanding about the drug diclofenac. The potential applications of diclofenac beyond its well-known anti-inflammatory properties for other diseases such as cancer are discussed, along with existing limitations.

Abstract

Diclofenac is a highly prescribed non-steroidal anti-inflammatory drug (NSAID) that relieves inflammation, pain, fever, and aches, used at different doses depending on clinical conditions. This drug inhibits cyclooxygenase-1 and cyclooxygenase-2 enzymes, which are responsible for the generation of prostaglandin synthesis. To improve current diclofenac-based therapies, we require new molecular systematic therapeutic approaches to reduce complex multifactorial effects. However, the critical challenge that appears with diclofenac and other drugs of the same class is their side effects, such as signs of stomach injuries, kidney problems, cardiovascular issues, hepatic issues, and diarrhea. In this article, we discuss why defining diclofenac-based mechanisms, pharmacological features, and its medicinal properties are needed to direct future drug development against neurodegeneration and imperfect ageing and to improve cancer therapy. In addition, we describe various advance molecular mechanisms and fundamental aspects linked with diclofenac which can strengthen and enable the better designing of new derivatives of diclofenac to overcome critical challenges and improve their applications.

Effects of Non-Opioid Analgesics on the Cell Membrane of Skin and Gastrointestinal Cancers

Skin and gastrointestinal cancer cells are the target of research by many scientists due to the increasing morbidity and mortality rates around the world. New indications for drugs used in various conditions are being discovered. Non-opioid analgesics are worth noting as very popular, widely available, relatively cheap medications. They also have the ability to modulate the membrane components of tumor cells. The aim of this review is to analyze the impact of diclofenac, ibuprofen, naproxen, acetylsalicylic acid and paracetamol on skin and gastrointestinal cancers cell membrane. These drugs may affect the membrane through topical application, at the in vitro and in vivo level after oral or parenteral administration. They can lead to up- or downregulated expression of receptors, transporters and other molecules associated with plasma membrane. Medications may also alter the lipid bilayer composition of membrane, resulting in changes in its integrity and fluidity. Described modulations can cause the visualization of cancer cells, enhanced response of the immune system and the initiation of cell death. The outcome of this is inhibition of progression or reduction of tumor mass and supports chemotherapy. In conclusion, non-opioid analgesics may be used in the future as adjunctive therapy for the treatment of these cancers.

Three birds with one stone: co-encapsulation of diclofenac and DL-menthol for realizing enhanced energy deposition, glycolysis inhibition and anti-inflammation in HIFU surgery

Despite attracting increasing attention in clinic, non-invasive high-intensity focused ultrasound (HIFU) surgery still commonly suffers from tumor recurrence and even matastasis due to the generation of thermo-resistance in non-apoptotic tumor cells and adverse therapy-induced inflammation with enhanced secretion of growth factors in irradiated region. In this work, inspired by the intrinsic property that the expression of thermo-resistant heat shock proteins (HSPs) is highly dependent with adenosine triphosphate (ATP), dual-functionalized diclofenac (DC) with anti-inflammation and glycolysis-inhibition abilities was successfully co-encapsulated with phase-change dl-menthol (DLM) in poly(lactic-co-glycolic acid) nanoparticles (DC/DLM@PLGA NPs) to realize improved HIFU surgery without causing adverse inflammation. Both in vitro and in vivo studies demonstrated the great potential of DC/DLM@PLGA NPs for serving as an efficient synergistic agent for HIFU surgery, which can not only amplify HIFU ablation efficacy through DLM vaporization-induced energy deposition but also simultaneously sensitize tumor cells to hyperthermia by glycolysis inhibition as well as diminished inflammation. Thus, our study provides an efficient strategy for simultaneously improving the curative efficiency and diminishing the harmful inflammatory responses of clinical HIFU surgery.

A Low Membrane Hsp70 Expression in Tumor Cells With Impaired Lactate Metabolism Mediates Radiosensitization by NVP-AUY922

As overexpression and membrane localization of stress proteins together with high lactate levels promote radioresistance in tumor cells, we studied the effect of the Hsp90 inhibitor NVP-AUY922 on the cytosolic and membrane expression of heat shock proteins (HSPs) and radiosensitivity in murine melanoma (B16F10) and human colorectal (LS174T) wildtype (WT) and lactate dehydrogenases A/B double knockout (LDH^−/−) tumor cells. Double knockout for LDHA/B has been found to reduce cytosolic as well as membrane HSP levels, whereas treatment with NVP-AUY922 stimulates the synthesis of Hsp27 and Hsp70, but does not affect membrane Hsp70 expression. Despite NVP-AUY922-inducing elevated levels of cytosolic HSP, radiosensitivity was significantly increased in WT cells and even more pronounced in LDH^−/− cells. An impaired lipid metabolism in LDH^−/− cells reduces the Hsp70 membrane-anchoring sphingolipid globotriaosylceramide (Gb3) and thereby results in a decreased Hsp70 cell surface density on tumor cells. Our results demonstrate that the membrane Hsp70 density, but not cytosolic HSP levels determines the radiosensitizing effect of the Hsp90 inhibitor NVP-AUY922 in LDH^−/− cells.

Pyruvate Dehydrogenase Kinase Inhibition by Dichloroacetate in Melanoma Cells Unveils Metabolic Vulnerabilities

Melanoma is characterized by high glucose uptake, partially mediated through elevated pyruvate dehydrogenase kinase (PDK), making PDK a potential treatment target in melanoma. We aimed to reduce glucose uptake in melanoma cell lines through PDK inhibitors dichloroacetate (DCA) and AZD7545 and through PDK knockdown, to inhibit cell growth and potentially unveil metabolic co-vulnerabilities resulting from PDK inhibition. MeWo cells were most sensitive to DCA, while SK-MEL-2 was the least sensitive, with IC₅₀ values ranging from 13.3 to 27.0 mM. DCA strongly reduced PDH phosphorylation and increased the oxygen consumption rate:extracellular acidification rate (OCR:ECAR) ratio up to 6-fold. Knockdown of single PDK isoforms had similar effects on PDH phosphorylation and OCR:ECAR ratio as DCA but did not influence sensitivity to DCA. Growth inhibition by DCA was synergistic with the glutaminase inhibitor CB-839 (2- to 5-fold sensitization) and with diclofenac, known to inhibit monocarboxylate transporters (MCTs) (3- to 8-fold sensitization). CB-839 did not affect the OCR:ECAR response to DCA, whereas diclofenac strongly inhibited ECAR and further increased the OCR:ECAR ratio. We conclude that in melanoma cell lines, DCA reduces proliferation through reprogramming of cellular metabolism and synergizes with other metabolically targeted drugs.

Co-delivery of photosensitizer and diclofenac through sequentially responsive bilirubin nanocarriers for combating hypoxic tumors

Considering that photodynamic therapy (PDT)-induced oxygen consumption and microvascular damage could exacerbate hypoxia to drive more glycolysis and angiogenesis, a novel approach to potentiate PDT and overcome the resistances of hypoxia is avidly needed. Herein, morpholine-modified PEGylated bilirubin was proposed to co-deliver chlorin e6, a photosensitizer, and diclofenac (Dc). In acidic milieu, the presence of morpholine could enable the nanocarriers to selectively accumulate in tumor cells, while PDT-generated reactive oxidative species (ROS) resulted in the collapse of bilirubin nanoparticles and rapid release of Dc. Combining with Dc showed a higher rate of apoptosis over PDT alone and simultaneously triggered a domino effect, including blocking the activity and expression of lactate dehydrogenase A (LDHA), interfering with lactate secretion, suppressing the activation of various angiogenic factors and thus obviating hypoxia-induced resistance-glycolysis and angiogenesis. In addition, inhibition of hypoxia-inducible factor-1α (HIF-1α) by Dc alleviated hypoxia-induced resistance. This study offered a sequentially responsive platform to achieve sufficient tumor enrichment, on-demand drug release and superior anti-tumor outcomes in vitro and in vivo.

Fighting in a wasteland: deleterious metabolites and antitumor immunity

As cancers progress, they produce a local environment that acts to redirect, paralyze, exhaust, or otherwise evade immune detection and destruction. The tumor microenvironment (TME) has long been characterized as a metabolic desert, depleted of essential nutrients such as glucose, oxygen, and amino acids, that starves infiltrating immune cells and renders them dysfunctional. While not incorrect, this perspective is only half the picture. The TME is not a metabolic vacuum, only consuming essential nutrients and never producing by-products. Rather, the by-products of depleted nutrients, “toxic” metabolites in the TME such as lactic acid, kynurenine, ROS, and adenosine, play an important role in shaping immune cell function and cannot be overlooked in cancer immunotherapy. Moreover, while the metabolic landscape is distinct, it is not unique, as these toxic metabolites are encountered in non-tumor tissues, where they evolutionarily shape immune cells and their response. In this Review, we discuss how depletion of essential nutrients and production of toxic metabolites shape the immune response within the TME and how toxic metabolites can be targeted to improve current cancer immunotherapies.

A metformin-based nanoreactor alleviates hypoxia and reduces ATP for cancer synergistic therapy

Severe hypoxia in solid tumors limits the efficacy of oxygen (O₂)-dependent photodynamic therapy (PDT). The overexpressed heat shock proteins (HSPs) in tumor cells hamper the effect of photothermal therapy (PTT). Herein, a tumor oxygenation-enhanced and ATP-reduced gelatin nanoreactor (MCGPD ∼ RGD NPs) for PDT/PTT-augmented combination cancer therapy is reported. In this nanosystem, the Arg-Gly-Asp (RGD) peptides of MCGPD ∼ RGD NPs can ensure accurate recognition and sufficient accumulation in the tumor site. After accumulation, doxorubicin (DOX) can be released from MCGPD ∼ RGD NPs in a mild acidic tumor microenvironment (TME) for highly efficient chemotherapy. Upon 808 nm laser irradiation, the overexpressed matrix metalloproteinase-2 (MMP-2) in the TME and the heat produced from the PDA coating trigger Gel NP degradation to expose chlorin e6 (Ce6) and Met from the cavity of MCGPD ∼ RGD NPs. The exposed Met elevates the O₂ content and reduces ATP production in tumor sites to spur the successful O₂-dependent PDT and HSP-mediated PTT. The heat generated by the PDA coating directly kills the tumor cells to ensure PTT and amplifies the chemotherapeutic effect. In vitro and in vivo assays indicate that MCGPD ∼ RGD NPs have excellent ability to promote cell apoptosis and to inhibit tumor growth. Overall, this smart responsive hydrogel nanosystem with hypoxia-relieving capacity and ATP-decreasing performance provides a promising strategy against cancer.

Polyamine homeostasis-based strategies for cancer: The role of combination regimens

Spermine, spermidine and putrescine polyamines are naturally occurring ubiquitous positively charged amines and are essential metabolites for biological functions in our life. These compounds play a crucial role in many cell processes, including cellular proliferation, growth, and differentiation. Intracellular levels of polyamines depend on their biosynthesis, transport and degradation. Polyamine levels are high in cancer cells, which leads to the promotion of tumor growth, invasion and metastasis. Targeting polyamine metabolism as an anticancer strategy is considerably rational. Due to compensatory mechanisms, a single strategy does not achieve satisfactory clinical effects when using a single agent. Combination regimens are more clinically promising for cancer chemoprevention because they work synergistically with causing little or no adverse effects due to each individual agent being used at lower doses. Moreover, bioactive substances have advantages over single chemical agents because they can affect multiple targets. In this review, we discuss anticancer strategies targeting polyamine metabolism and describe how combination treatments and effective natural active ingredients are promising therapies. The existing research suggests that polyamine metabolic enzymes are important therapeutic targets and that combination therapies can be more effective than monotherapies based on polyamine depletion.

NIR-II fluorescence imaging guided tumor-specific NIR-II photothermal therapy enhanced by starvation mediated thermal sensitization strategy

Photothermal therapy (PTT) is hampered by limited light penetration depth and cell thermoresistance induced by over-expressed heat shock proteins (HSPs). Herein, we proposed a tumor-specific enhanced NIR-II PTT through the starvation mediated thermal sensitization strategy. A semiconducting polymer with superior NIR-II fluorescence imaging (FI) performance and NIR-II PTT efficacy was synthesized and encapsulated into folate modified liposomes, together with a glycolysis inhibitor, 2-deoxy-d-glucose (2DG). Upon specifically targeting folate receptors and guidance of NIR-II FI, spatiotemporal 2DG release could be achieved by the trigger of NIR-II photothermal effect. The released 2DG could not only deplete the energy supply of tumor cells by inhibiting tumor anaerobic glycolysis, but also decrease the ATP levels and hamper the production of HSPs, ultimately enhancing the tumor thermal sensitivity toward PTT. Owing to the sensitization effect of 2DG, tumor cells with overexpressed folate receptors could be significantly damaged by NIR-II PTT with an enhanced therapeutic efficiency. The work provided a promising strategy for specific starvation/NIR-II PTT synergistic therapy towards tumors.

Diclofenac N-Derivatives as Therapeutic Agents with Anti-Inflammatory and Anti-Cancer Effect

A series of diclofenac N-derivatives (2, 4, 6, 8c, 9c, 10a-c) were synthesized in order to test their anti-cancer and anti-inflammatory effects. The anticarcinogen activity has been assayed against three cancer cell lines: HT29, human colon cancer cells; Hep-G2, human hepatic cells; and B16-F10, murine melanoma cells. First, we determined the cytotoxicity of the different compounds, finding that the most effective compound was compound 8c against all cell lines and both compounds 4 and 6 in human Hep-G2 and HT29 cell lines. Compounds 4 and 8c were selected for the percentage of apoptosis determination, cell cycle distribution, and mitochondrial membrane potential measure because these products presented the lowest IC₅₀ values in two of the three cancer cell lines assayed (B16-F10 and HepG2), and were two of the three products with lowest IC₅₀ in HT29 cell line. Moreover, the percentages of apoptosis induction were determined for compounds 4 and 8c, showing that the highest values were between 30 to 60%. Next, the effects of these two compounds were observed on the cellular cycle, resulting in an increase in the cell population in G2/M cell cycle phase after treatment with product 8c, whereas compound 4 increased the cells in phase G0/G1, by possible differentiation process induction. Finally, to determine the possible apoptosis mechanism triggered by these compounds, mitochondrial potential was evaluated, indicating the possible activation of extrinsic apoptotic mechanism. On the other hand, we studied the anti-inflammatory effects of these diclofenac (DCF) derivatives on lipopolysaccharide (LPS) activated RAW 264.7 macrophages-monocytes murine cells by inhibition of nitric oxide (NO) production. As a first step, we determined the cytotoxicity of the synthesized compounds, as well as DCF, against these cells. Then, sub-cytotoxic concentrations were used to determine NO release at different incubation times. The greatest anti-inflammatory effect was observed for products 2, 4, 8c, 10a, 10b, and 9c at 20 µg·mL^-1 concentration after 48 h of treatment, with inhibition of produced NO between 60 to 75%, and a concentration that reduces to the 50% the production of NO (IC_{50 NO}) between 2.5 to 25 times lower than that of DCF. In this work, we synthesized and determined for the first time the anti-cancer and anti-inflammatory potential of eight diclofenac N-derivatives. In agreement with the recent evidences suggesting that inflammation may contribute to all states of tumorigenesis, the development of these new derivatives capable of inducing apoptosis and anti-inflammatory effects at very low concentrations represent new effective therapeutic strategies against these diseases.

Diclofenac impairs the proliferation and glucose metabolism of triple-negative breast cancer cells by targeting the c-Myc pathway

Triple-negative breast cancer (TNBC) cells obtain energy mainly through aerobic glycolysis, and their glycolytic rate is significantly higher compared with that of non-TNBC cells. Glucose transporter 1 (GLUT1) is a transmembrane transporter necessary for the entry of glucose into tumor cells, hexokinase (HK) is a key enzyme in the glycolytic pathway, and both are targets of the transcription factor c-Myc. c-Myc can promote aerobic glycolysis by upregulating GLUT1 expression and enhancing HK activity. c-Myc and GLUT1 are highly expressed in TNBC. The non-steroidal anti-inflammatory drug diclofenac can inhibit glycolysis in melanoma cells and thereby promote apoptosis by downregulating c-Myc and GLUT1. To explore the effect of diclofenac on the energy metabolism of TNBC cells and determine the underlying mechanism, a comparative study in two TNBC cell lines (MDA-MB-231 and HCC1937) and one non-TNBC cell line (MCF-7) was conducted. Cell proliferation was detected by Cell Counting Kit-8 (CCK-8) and flow cytometric assays; GLUT1 and c-Myc expression was measured by western blotting. Diclofenac significantly inhibited cell proliferation, downregulated GLUT1 and c-Myc expression, and decreased HK activity in TNBC cells compared with non-TNBC cells. In conclusion, the studies suggested that diclofenac inhibited cell glycolysis and suppressed TNBC cell growth by decreasing GLUT1 protein expression and HK activity through the c-Myc pathway.

Effect of conducting/thermoresponsive polymer ratio on multitasking nanogels

Semi-interpenetrated nanogels (NGs) able to release and sense diclofenac (DIC) have been designed to act as photothermal agents with the possibility to ablate cancer cells using mild-temperatures (<45 °C). Combining mild heat treatments with simultaneous chemotherapy appears as a very promising therapeutic strategy to avoid heat resistance or damaging the surrounding tissues. Particularly, NGs consisted on a poly(N-isopropylacrylamide) (PNIPAM) and dendritic polyglycerol (dPG) mesh containing a semi-interpenetrating network (SIPN) of poly(hydroxymethyl 3,4-ethylenedioxythiophene) (PHMeEDOT). The PHMeEDOT acted as photothermal and conducting agent, while PNIPAM-dPG NG provided thermoresponsivity and acted as stabilizer. We studied how semi-interpenetration modified the physicochemical characteristics of the thermoresponsive SIPN NGs and selected the best condition to generate a multifunctional photothermal agent. The thermoswitchable conductiveness of the multifunctional NGs and the redox activity of DIC could be utilized for its electrochemical detection. Besides, as proof of the therapeutic concept, we investigated the combinatorial effect of photothermal therapy (PTT) and DIC treatment using the HeLa cancer cell line in vitro. Within 15 min NIR irradiation without surpassing 45 °C we were able to kill 95% of the cells, demonstrating the potential of SIPN NGs as drug carriers, sensors and agents for mild PTT.

Restricting Glycolysis Preserves T Cell Effector Functions and Augments Checkpoint Therapy

Tumor-derived lactic acid inhibits T and natural killer (NK) cell function and, thereby, tumor immunosurveillance. Here, we report that melanoma patients with high expression of glycolysis-related genes show a worse progression free survival upon anti-PD1 treatment. The non-steroidal anti-inflammatory drug (NSAID) diclofenac lowers lactate secretion of tumor cells and improves anti-PD1-induced T cell killing in vitro. Surprisingly, diclofenac, but not other NSAIDs, turns out to be a potent inhibitor of the lactate transporters monocarboxylate transporter 1 and 4 and diminishes lactate efflux. Notably, T cell activation, viability, and effector functions are preserved under diclofenac treatment and in a low glucose environment in vitro. Diclofenac, but not aspirin, delays tumor growth and improves the efficacy of checkpoint therapy in vivo. Moreover, genetic suppression of glycolysis in tumor cells strongly improves checkpoint therapy. These findings support the rationale for targeting glycolysis in patients with high glycolytic tumors together with checkpoint inhibitors in clinical trials.

Metabolic Plasticity of Melanoma Cells and Their Crosstalk With Tumor Microenvironment

Cutaneous melanoma (CM) is a highly aggressive and drug resistant solid tumor, showing an impressive metabolic plasticity modulated by oncogenic activation. In particular, melanoma cells can generate adenosine triphosphate (ATP) during cancer progression by both cytosolic and mitochondrial compartments, although CM energetic request mostly relies on glycolysis. The upregulation of glycolysis is associated with constitutive activation of BRAF/MAPK signaling sustained by BRAF^V600E kinase mutant. In this scenario, the growth and progression of CM are strongly affected by melanoma metabolic changes and interplay with tumor microenvironment (TME) that sustain tumor development and immune escape. Furthermore, CM metabolic plasticity can induce a metabolic adaptive response to BRAF/MEK inhibitors (BRAFi/MEKi), associated with the shift from glycolysis toward oxidative phosphorylation (OXPHOS). Therefore, in this review article we survey the metabolic alterations and plasticity of CM, its crosstalk with TME that regulates melanoma progression, drug resistance and immunosurveillance. Finally, we describe hallmarks of melanoma therapeutic strategies targeting the shift from glycolysis toward OXPHOS.

Lactate dehydrogenase: a marker of diminished antitumor immunity

Lactate dehydrogenase (LDH) levels are inversely related with response to checkpoint inhibitors. Elevated LDH levels are the product of enhanced glycolytic activity of the tumor and tumor necrosis due to hypoxia, the latter being associated with high tumor burden. In this review, we elucidate the effects of glycolysis and hypoxia on antitumor immunity and set forth ways to improve response to immunotherapy in cancer patients with elevated LDH levels. We discuss the current knowledge on combining immunotherapy with glycolysis inhibitors, anti-acidifying drugs, anti-angiogenic or cytoreductive therapy.

Competitive glucose metabolism as a target to boost bladder cancer immunotherapy

Bladder cancer - the tenth most frequent cancer worldwide - has a heterogeneous natural history and clinical behaviour. The predominant histological subtype, urothelial bladder carcinoma, is characterized by high recurrence rates, progression and both primary and acquired resistance to platinum-based therapy, which impose a considerable economic burden on health-care systems and have substantial effects on the quality of life and the overall outcomes of patients with bladder cancer. The incidence of urothelial tumours is increasing owing to population growth and ageing, so novel therapeutic options are vital. Based on work by The Cancer Genome Atlas project, which has identified targetable vulnerabilities in bladder cancer, immune checkpoint inhibitors (ICIs) have arisen as an effective alternative for managing advanced disease. However, although ICIs have shown durable responses in a subset of patients with bladder cancer, the overall response rate is only ~15-25%, which increases the demand for biomarkers of response and therapeutic strategies that can overcome resistance to ICIs. In ICI non-responders, cancer cells use effective mechanisms to evade immune cell antitumour activity; the overlapping Warburg effect machinery of cancer and immune cells is a putative determinant of the immunosuppressive phenotype in bladder cancer. This energetic interplay between tumour and immune cells leads to metabolic competition in the tumour ecosystem, limiting nutrient availability and leading to microenvironmental acidosis, which hinders immune cell function. Thus, molecular hallmarks of cancer cell metabolism are potential therapeutic targets, not only to eliminate malignant cells but also to boost the efficacy of immunotherapy. In this sense, integrating the targeting of tumour metabolism into immunotherapy design seems a rational approach to improve the therapeutic efficacy of ICIs.

Metformin as Potential Therapy for High-Grade Glioma

Metformin (MET), 1,1-dimethylbiguanide hydrochloride, is a biguanide drug used as the first-line medication in the treatment of type 2 diabetes. The recent years have brought many observations showing metformin in its new role. The drug, commonly used in the therapy of diabetes, may also find application in the therapy of a vast variety of tumors. Its effectiveness has been demonstrated in colon, breast, prostate, pancreatic cancer, leukemia, melanoma, lung and endometrial carcinoma, as well as in gliomas. This is especially important in light of the poor options offered to patients in the case of high-grade gliomas, which include glioblastoma (GBM). A thorough understanding of the mechanism of action of metformin can make it possible to discover new drugs that could be used in neoplasm therapy.

Hypoxia Compromises Anti-Cancer Immune Responses

Hypoxia, one of the hallmarks of cancer, is caused by an insufficient oxygen supply, mostly due to a chaotic, deficient tumor microcirculation. Apart from a hypoxia-mediated resistance to standard therapies, modulated gene and protein expression, genetic instability and malignant progression, hypoxia also plays a pivotal role in anti-cancer immune responses by (a) reducing survival, cytolytic and migratory activity of effector cells such as CD4⁺ cells, CD8⁺ cytotoxic T cells, natural killer-like T cells and natural killer cells, (b) reducing the production and release of effector cytokines, (c) supporting immunosuppressive cells such as regulatory T cells, myeloid-derived suppressor cells and M2 macrophages, (d) increasing the production and release of immunosuppressive cytokines, and (e) inducing the expression of immune checkpoint inhibitors. In this minireview, immunosuppressive effects of hypoxia- and HIF-1a-driven traits in cancers are described.

The role of P2X7 receptor in prognosis and metastasis of colorectal cancer

PURPOSE

Colorectal cancer (CRC) is one of the leading causes of cancer mortality in the world. P2X7 receptor (P2X7R), encoded by the P2rx7 gene, is a trimeric ion channel activated by extracellular Adenosine triphosphate and is widely expressed in various types of tissues and tumors to regulate inflammation, cell proliferation, or death. The discovery of new biomarkers and understanding the role of P2X7R in CRC are therefore critical to improving the prognosis and treatment of CRC.

MATERIALS AND METHODS

P2X7R expression was analyzed in CRC tumor samples and normal colorectal tissues from 97 patients and various colon cancer cell lines. The correlation of tumor antigens, survival periods, and P2X7R expression were documented.

RESULTS

P2X7R^High and P2X7R^Low populations were observed in CRC patients. P2X7R^High patients had relatively shorter survival periods, higher levels of serum carcinoembryonic antigen, and greater numbers of advanced tumors. In addition, P2X7R expression had a significant up-regulation in metastatic CRC and metastatic CRC cell lines, which indicates that P2X7R expression is positively associated with metastasis.

CONCLUSIONS

P2X7R expression might be a potential biomarker for prognosis and metastasis of CRC.

Topical Diclofenac Reprograms Metabolism and Immune Cell Infiltration in Actinic Keratosis

Background: Melanoma and squamous cell carcinoma of the skin are characterized by an altered glucose metabolism, but little is known about metabolic changes in precancerous skin lesions such as actinic keratosis (AK). Here, we studied the central carbon metabolism and immune cell infiltrate of actinic keratosis lesions before, under, and 4 weeks after treatment with topical diclofenac (Solaraze®).

Methods: This study was designed as a prospective, randomized, controlled, monocentric investigation (ClinicalTrials.gov Identifier: NCT01935531). Myeloid and T cell infiltration was analyzed in skin biopsies from 28 patients by immunohistochemistry. Furthermore, immune cell activation was determined via quantitative real-time PCR (IFN-γ, IL-10, CSF1, TGF-β, IL-6). Glucose, amino acid and Krebs' cycle metabolism was studied by mass spectrometry prior, during and after treatment with topical diclofenac. Biopsies from sun-exposed, untreated, healthy skin served as controls.

Results: Increased lactate and decreased glucose levels suggested accelerated glycolysis in pre-treatment AK. Further, levels of Krebs' cycle intermediates other than citrate and amino acids were elevated. Analysis of the immune infiltrate revealed less epidermal CD1a+ cells but increased frequencies of dermal CD8+ T cells in AK. Treatment with diclofenac reduced lactate and amino acid levels in AK, especially in responding lesions, and induced an infiltration of dermal CD8+ T cells accompanied by high IFN-γ mRNA expression, suggesting improved T cell function.

Discussion: Our study clearly demonstrated that not only cancers but also pre-malignant skin lesions, like AK, exhibit profound changes in metabolism, correlating with an altered immune infiltrate. Diclofenac normalizes metabolism, immune cell infiltration and function in AK lesions, suggesting a novel mechanism of action.

MYC Expression and Metabolic Redox Changes in Cancer Cells: A Synergy Able to Induce Chemoresistance

Chemoresistance is due to multiple factors including the induction of a metabolic adaptation of tumor cells. In fact, in these cells, stress conditions induced by therapies stimulate a metabolic reprogramming which involves the strengthening of various pathways such as glycolysis, glutaminolysis and the pentose phosphate pathway. This metabolic reprogramming is the result of a complex network of mechanisms that, through the activation of oncogenes (i.e., MYC, HIF1, and PI3K) or the downregulation of tumor suppressors (i.e., TP53), induces an increased expression of glucose and/or glutamine transporters and of glycolytic enzymes. Therefore, in order to overcome chemoresistance, it is necessary to develop combined therapies which are able to selectively and simultaneously act on the multiple molecular targets responsible for this adaptation. This review is focused on highlighting the role of MYC in modulating the epigenetic redox changes which are crucial in the acquisition of therapy resistance.

Toxicity of 10 organic micropollutants and their mixture: Implications for aquatic risk assessment

Micropollutants, as a serious water pollution issue, raise considerable toxicological concerns, particularly when present as components of complex mixtures. Due to the interactions of environmental pollution components (contaminant), the micropollutant problem is increasingly complex, thus, water quality of organic chemical contamination assessed substance-by-substance might lead to underestimation in aquatic environmental risk assessment. To assess the aquatic environmental risk of micropollutants mixture, a total of 10 organic micropollutants were selected and analysed by an approach of integration of literature data, laboratory experiments and prediction techniques. The experiment results showed that all 10 micropollutants were capable of causing toxicity in zebrafish embryos, aquatic invertebrates and algae with the LC50 (50% lethal concentration) values from 1.14 mg/L to 14.37 mg/L. Triclosan, carbamazepine, diazinon and diuron were the most hazardous compounds in the Danube River and the Rhine River. The artificial mixture presented a strong antagonistic relationship, which demonstrated an independent action (IA) model of the mixture. Based on the observed toxicity data, the risk quotients (RQs) of environmental mixtures of the Danube River and the Rhine River were extrapolated. It can be concluded that the micropollutant mixture may pose a potential risk for aquatic ecosystems with the present environmentally measured concentrations in the Danube River and Rhine River. Mixture risk assessment results suggested that the toxicity of studied chemicals might be induced by dissimilar actions, which is in agreement with the mixture toxicity prediction of the IA model. The observed findings could be useful to establish an overview of the pressures, vision, measures and expectations for hazardous substances pollution, which can help in making to informed decisions to reduce the concentration and bioactive fraction of pollutants.

Controlled and tuneable drug release from electrospun fibers and a non-invasive approach for cytotoxicity testing

Electrospinning is an attractive method to generate drug releasing systems. In this work, we encapsulated the cell death-inducing drug Diclofenac (DCF) in an electrospun poly-L-lactide (PLA) scaffold. The scaffold offers a system for a sustained and controlled delivery of the cytotoxic DCF over time making it clinically favourable by achieving a prolonged therapeutic effect. We exposed human dermal fibroblasts (HDFs) to the drug-eluting scaffold and employed multiphoton microscopy and fluorescence lifetime imaging microscopy. These methods were suitable for non-invasive and marker-independent assessment of the cytotoxic effects. Released DCF induced changes in cell morphology and glycolytic activity. Furthermore, we showed that drug release can be influenced by adding dimethyl sulfoxide as a co-solvent for electrospinning. Interestingly, without affecting the drug diffusion mechanism, the resulting PLA scaffolds showed altered fibre morphology and enhanced initial DCF burst release. The here described model could represent an interesting way to control the diffusion of encapsulated bio-active molecules and test them using a marker-independent, non-invasive approach.

Metabolic therapies inhibit tumor growth in vivo and in silico

In the recent years, cancer research succeeded with sensitive detection methods, targeted drug delivery systems, and the identification of a large set of genes differently expressed. However, although most therapies are still based on antimitotic agents, which are causing wide secondary effects, there is an increasing interest for metabolic therapies that can minimize side effects. In the early 20th century, Otto Warburg revealed that cancer cells rely on the cytoplasmic fermentation of glucose to lactic acid for energy synthesis (called "Warburg effect"). Our investigations aim to reverse this effect in reprogramming cancer cells' metabolism. In this work, we present a metabolic therapy specifically targeting the activity of specific enzymes of central carbon metabolism, combining the METABLOC bi-therapeutic drugs combination (Alpha Lipoic Acid and Hydroxycitrate) to Metformin and Diclofenac, for treating tumors implanted in mice. Furthermore, a dynamic metabolic model describing central carbon metabolism as well as fluxes targeted by the drugs allowed to simulate tumors progression in both treated and non-treated mice, in addition to draw hypotheses on the effects of the drugs on tumor cells metabolism. Our model predicts metabolic therapies-induced reversed Warburg effect on tumor cells.

Diclofenac conjugates with biocides through silver(I) ions (CoMeD's); Development of a reliable model for the prediction of anti-proliferation of NSAID's-silver formulations

The conjugation of diclofenac (DICLH), a Non-Steroidal Anti-inflammatory Drug (NSAID), with biocides such as dimethyl sulfoxide (DMSO) and triphenylphosphine (TPP), through silver(I) ions, results into the chemical [Ag_n(DICL)_n(L)_m]_k (L = DMSO and n = 2, m = 2, k = infinite (1); L = TPP and n = 1, m = 2, k = 1 (2)). The compounds were characterized by m.p., FT-IR, UV-vis and ¹H NMR spectroscopic techniques. The crystal and molecular structures of 1-2 were determined by X-ray crystallography. The in vitro cytotoxic activity of 1-2 against the human breast adenocarcinoma cancer cells MCF-7 (hormone dependent) and MDA-MB-231 (hormone independent) reveals that the 1 inhibits the MCF-7 rather than the MDA-MB-231 cells, suggesting hormone mimetic behaviour. Compound 2 inhibits both cancerous cell lines, stronger than cisplatin. Both compounds inhibit MCF-7 cells migration. Compounds 1-2, exhibit, lower toxicity against fetal lung fibroblast (MRC-5) cells than cisplatin. Their genotoxicity was evaluated on MRC-5 cells. The molecular mechanism of 1-2 against MCF-7 cells was clarified by (i) their cell cycle arrest study (ii) their mitochondrial membrane permeability (iii) their binding affinity towards Calf Thymus (CT)-DNA and (iv) their inhibitory activity against the enzyme lipoxygenase (LOX). Regression analysis of the data obtained for [Ag(NSAID)(Ar₃P)_m] (NSAID = p‑hydroxy‑benzoic acid (p-HO-BZAH), salicylic acid (SALH₂), aspirin (ASPH), naproxen (NAPRH), nimesulide (NIMH); L = TPP, Tri(p‑tolyl)phosphine (TPTP), Tri(o‑tolyl)phosphine (TOTP), Tri(m‑tolyl)phosphine (TMTP); m = 2 or 3) and [Ag(DICL)₂(DMSO)₂]_k (k = infinite) was performed. Considering the biological results (IC₅₀) as dependent variable a theoretical equation is obtained for these compounds. The calculated IC₅₀ values are compared satisfactorily with the corresponding experimental inhibitory activity of the complexes.

Use of statins or NSAIDs and survival of patients with high-grade glioma

Background

High-grade glioma (HGG) is associated with a limited prognosis. Drug repurposing has become of increasing interest to improve standard therapy. Statins and NSAIDs inhibit glioma cell growth in vitro and in vivo, but data on statin and NSAID treatment in relation to survival of patients with HGG are sparse.

Methods

We performed multivariable adjusted Cox-regression analyses among 1,093 patients with HGG from a regional cancer registry to obtain Hazard Ratios (HRs) with 95% Confidence Intervals (CIs) for overall survival (OS) and progression-free survival (PFS) according to treatment with statins or NSAIDs. Data on dose and duration of treatment was mostly lacking in our analysis, therefore we were not able to perform dose-response analyses.

Results

Use of statins was unrelated to OS or PFS of glioma patients. Use of aspirin was associated with prolonged OS and PFS in patients with WHO grade III, but not WHO grade IV glioma. Use of other NSAIDs (diclofenac, ibuprofen) or non-NSAID analgesics (paracetamol) was mostly unrelated to survival of glioma patients. Use of selective COX-2 inhibitors and metamizol was related to inferior patient survival in parts of the analyses.

Conclusions

Use of statins or NSAIDS, including aspirin, was not associated with prolonged OS or PFS of patients with WHO grade IV glioma in our selected cohort. There was an indication for improved survival in patients with WHO grade III glioma using aspirin, but further studies are needed to confirm our first observation.

Metabolic targeting synergizes with MAPK inhibition and delays drug resistance in melanoma

Tumors, including melanomas, frequently show an accelerated glucose metabolism. Mutations in the v-Raf murine sarcoma viral oncogene homolog B (BRAF), detected in about 50% of all melanomas, result in further enhancement of glycolysis. Therefore anti-metabolic substances might enhance the impact of RAF inhibitors. We have identified the two non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac and lumiracoxib being able to restrict energy metabolism in human melanoma cells by targeting lactate release and oxidative phosphorylation (OXPHOS). In combination with the RAF inhibitor vemurafenib strong synergism was observed: Diclofenac as well as lumiracoxib increased the anti-glycolytic impact of vemurafenib and prevented RAF-inhibitor induced metabolic reprogramming towards OXPHOS. Consequently, both NSAIDs sensitized melanoma cells to vemurafenib triggered proliferation arrest and enhanced the anti-tumor effect of RAF inhibitors from cytostatic to cytotoxic. Furthermore the addition of NSAIDs delayed the onset of RAF inhibitor resistance, most likely by counteracting the upregulation of MITF. Our data suggest that selected NSAIDs could be a promising combination partner for MAPK pathway inhibitors for the treatment of BRAF^V600E mutated melanomas.

Combined Metabolic Targeting With Metformin and the NSAIDs Diflunisal and Diclofenac Induces Apoptosis in Acute Myeloid Leukemia Cells

The accelerated metabolism of tumor cells, inevitable for maintaining high proliferation rates, is an emerging target for tumor therapy. Increased glucose and lipid metabolism as well as mitochondrial activity have been shown in solid tumors but also in leukemic cells. As tumor cells are able to escape the blockade of one metabolic pathway by a compensatory increase in other pathways, treatment strategies simultaneously targeting metabolism at different sites are currently developed. However, the number of clinically applicable anti-metabolic drugs is still limited. Here, we analyzed the impact of the anti-diabetic drug metformin alone or in combination with two non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac and diflunisal on acute myeloid leukemia (AML) cell lines and primary patient blasts. Diclofenac but not diflunisal reduced lactate secretion in different AML cell lines (THP-1, U937, and KG-1) and both drugs increased respiration at low concentrations. Despite these metabolic effects, both NSAIDs showed a limited effect on tumor cell proliferation and viability up to a concentration of 0.2 mM. In higher concentrations of 0.4–0.8 mM diflunisal alone exerted a clear effect on proliferation of AML cell lines and blocked respiration. Single treatment with the anti-diabetic drug metformin blocked mitochondrial respiration, but proliferation and viability were not affected. However, combining all three drugs exerted a strong cytostatic and cytotoxic effect on THP-1 cells. Comparable to the results obtained with THP-1 cells, the combination of all three drugs significantly reduced proliferation of primary leukemic blasts and induced apoptosis. Furthermore, NSAIDs supported the effect of low dose chemotherapy with cytarabine and reduced proliferation of primary AML blasts. Taken together we show that low concentrations of metformin and the two NSAIDs diclofenac and diflunisal exert a synergistic inhibitory effect on AML proliferation and induce apoptosis most likely by blocking tumor cell metabolism. Our results underline the feasibility of applying anti-metabolic drugs for AML therapy.

Drug Repurposing of Metabolic Agents in Malignant Glioma

Gliomas are highly invasive brain tumors with short patient survival. One major pathogenic factor is aberrant tumor metabolism, which may be targeted with different specific and unspecific agents. Drug repurposing is of increasing interest in glioma research. Drugs interfering with the patient’s metabolism may also influence glioma metabolism. In this review, we outline definitions and methods for drug repurposing. Furthermore, we give insights into important candidates for a metabolic drug repurposing, namely metformin, statins, non-steroidal anti-inflammatory drugs, disulfiram and lonidamine. Advantages and pitfalls of drug repurposing will finally be discussed.