bims-rehoca Biomed News
on Redox homeostasis in cancer
Issue of 2021‒07‒18
twenty-four papers selected by
Vittoria Raimondi
Veneto Institute of Oncology

  1. Biomaterials. 2021 Jul 07. pii: S0142-9612(21)00361-6. [Epub ahead of print]276 121005
      Discovering new strategies to overcome multidrug resistance (MDR) is still urgently needed. MDR is associated with the overexpression of transmembrane efflux pumps, and adenosine triphosphate (ATP) is indispensable for its function. Herein, we developed a pH- and glutathione (GSH)-responsive amphiphilic poly(disulfide acetal) (PCS) containing cinnamaldehyde (CA) and disulfide groups that amplify oxidative stress for anticancer drug delivery and simultaneously overcome drug resistance in cancer cells. Reactive oxygen species (ROS)-generating CA and the disulfide groups to deplete GSH and synergize to amplify oxidative stress in cancer cells by oxidizing nicotinamide adenine dinucleotide with hydrogen (NADH) to nicotinamide adenine dinucleotide (NAD+). The production of ATP is preferentially inhibited, leading to the malfunction of efflux pumps due to the lack of ATP and making resistant cells more impressionable to anticancer drugs. The in vitro and in vivo experiments confirmed that PCS could induce amplified oxidative stress and efficiently overcome MDR in cancer cells. We believe that the polymer with amplified oxidative stress in cancer cells holds great promise in developing polymer-based drug delivery systems to reverse MDR for cancer therapy.
    Keywords:  Cancer therapy; Overcome multidrug resistance; Oxidative stresses; Responsive polymer
  2. Onco Targets Ther. 2021 ;14 4047-4060
      Introduction: Glutathione reductase (GSR) provides reduced glutathione (GSH) to maintain redox homeostasis. Inhibition of GSR disrupts this balance, resulting in cell damage, which benefits cancer therapy. However, the effect of GSR inhibition on the tumorigenicity of human cervical cancer is not fully understood.Materials and Methods: Tissue microarray analysis was employed to determine GSR expression in cervical cancer tissues by immunohistochemical staining. Cell death was measured with PI/FITC-annexin V staining. mRNA levels were measured via quantitative RT-PCR. Protein expression was measured by Western blotting and flow cytometry. STAT3 deletion was performed with CRISPR/Cas9 technology. GSR knockdown was achieved by RNA interference. Reactive oxygen species (ROS) levels were measured by DCF staining. GSR enzymatic activity was measured with a GSR assay kit. The effect of GSR inhibition on the growth of tumors formed by cervical cancer cells was investigated using a xenograft model.
    Results: The expression of GSR was increased in human cervical cancer tissues, as shown by immunohistochemical staining. GSR knockdown by RNA interference in human cervical cancer cell lines resulted in cell death, suggesting the ability of GSR to maintain cancer cell survival. The STAT3 inhibitor 6-nitrobenzo[b]thiophene 1,1-dioxide (Stattic) also inhibited the enzymatic activity of GSR and induced the death of cervical cancer cells. More importantly, Stattic decreased the growth of xenograft tumors formed by cervical cancer cells in nude mice. Mechanistically, tumor cell death induced by Stattic-mediated GSR inhibition was ROS-dependent, since the ROS scavengers GSH and N-acetyl cysteine (NAC) reversed the effect of Stattic. In contrast, pharmacological and molecular inhibition of STAT3 did not induce the death of cervical cancer cells, suggesting a STAT3-independent activity of Stattic.
    Conclusion: Stattic inhibits the enzymatic activity of GSR and induces STAT3-independent but ROS-dependent death of cervical cancer cells, suggesting its potential application as a therapeutic agent for human cervical cancers.
    Keywords:  Stattic; cell death; cervical cancer; glutathione reductase; reactive oxygen species; tumor growth
  3. Front Oncol. 2021 ;11 682968
      Lapachol is a well-studied natural product that has been receiving great interest due to its anticancer properties that target oxidative stress. In the present work, two novel lapachol-containing ruthenium(II) complexes [Ru(Lap)(dppm)(bipy)]PF6 (1) and [Ru(Lap)(dppm)(phen)]PF6 (2) [Lap = lapachol, dppm = 1,1'-bis(diphosphino)methane, bipy = 2,2'-bipyridine, phen = 1,10-phenantroline] were synthesized, fully characterized, and investigated for their cellular and molecular responses on cancer cell lines. We found that both complexes exhibited a potent cytotoxic effect in a panel of cancer cell lines in monolayer cultures, as well as in a 3D model of multicellular spheroids formed from DU-145 human prostate adenocarcinoma cells. Furthermore, the complex (2) suppressed the colony formation, induced G2/M-phase arrest, and downregulated Aurora-B. The mechanism studies suggest that complex (2) stimulate the overproduction of reactive oxygen species (ROS) and triggers caspase-dependent apoptosis as a result of changes in expression of several genes related to cell proliferation and caspase-3 and -9 activation. Interestingly, we found that N-acetyl-L-cysteine, a ROS scavenger, suppressed the generation of intracellular ROS induced by complex (2), and decreased its cytotoxicity, indicating that ROS-mediated DNA damage leads the DU-145 cells into apoptosis. Overall, we highlighted that coordination of lapachol to phosphinic ruthenium(II) compounds considerably improves the antiproliferative activities of resulting complexes granting attractive selectivity to human prostate adenocarcinoma cells. The DNA damage response to ROS seems to be involved in the induction of caspase-mediated cell death that plays an important role in the complexes' cytotoxicity. Upon further investigations, this novel class of lapachol-containing ruthenium(II) complexes might indicate promising chemotherapeutic agents for prostate cancer therapy.
    Keywords:  3D-cell culture; DNA damage (comet assay); ROS - reactive oxygen species; apoptosis; lapachol; naphtoquinones
  4. Eur J Pharmacol. 2021 Jul 13. pii: S0014-2999(21)00498-2. [Epub ahead of print] 174345
      Ovarian cancer, characterized by rapid growth and asymptomatic development in the early stage, is the fifth common cancer in women. The deregulated expression of c-Myc in more than 50% of human tumors including ovarian cancer makes this oncogenic master transcription factor a potential therapeutic target for cancer treatment. In the present study, we evaluated the anti-tumor effects of 10058-F4, a small molecule c-Myc inhibitor, on ovarian cancer cells. We found that 10058-F4 not only inhibited the proliferation and clonal growth of ovarian cancer cells but also enhanced the cytotoxic effects of chemotherapeutic drugs. Our results also revealed that c-Myc inhibition using 10058-F4 increased the intracellular reactive oxygen species production coupled with suppressed expression of hTERT. RT-qPCR analysis indicated that 10058-F4 enhanced the mRNA levels of the forkhead box O (FOXO) family of transcription factors, including FOXO1, 3, and 4. Moreover, 10058-F4 induced G1 cell cycle arrest in 2008C13 ovarian cancer cells, along with increased expression of some key targets of FOXOs involved in the regulation of cell cycle such as p15, p21, p27, and GADD45A. The results of our study also showed that the 10058-F4-induced apoptosis in 2008C13 cell line was associated with the upregulation of FOXO downstream genes, including PUMA, Bim, and FasL. In conclusion, our results, for the first time, suggest that the anti-tumor effects of 10058-F4 in ovarian cancer cells might be mediated through upregulation of FOXO transcription factors and their key target genes involved in G1 cell cycle arrest, apoptosis, and autophagic cell death.
    Keywords:  10058-F4; FOXO; Ovarian cancer; Reactive Oxygen Species; c-Myc
  5. Antioxid Redox Signal. 2021 Jul 13.
      SIGNIFICANCE: Vitamin C (ascorbate), in regard to its effectiveness against malignancies, has had a controversial history in cancer treatment. It has been shown that in vitro and in vivo anticancer efficacy of ascorbate relies on its pro-oxidant effect mainly from an increased generation of reactive oxygen species (ROS). A growing understanding of its anticancer activities and pharmacokinetic properties has prompted scientists to reevaluate the significance of ascorbate in cancer treatment. Recent Advances: A recent resurge in ascorbate research emerged after discovering that, at high doses, ascorbate preferentially kills K-ras- and BRAF-mutant cancer cells. In addition, some of the main hallmarks of cancer cells, such as redox homeostasis and oxygen-sensing regulation (through inhibition of HIF-1α activity), are affected by vitamin C.CRITICAL ISSUES: Currently, there is no clear consensus from literature in regards to the beneficial effects of antioxidants. Results from both human and animal studies provide no clear evidence about the benefit of antioxidant treatment in preventing or suppressing cancer development. Since pro-oxidants may affect both normal and tumor cells, the extremely low toxicity of ascorbate represents a main advantage. This guarantees the safe inclusion of ascorbate in clinical protocols to treat cancer patients.
    FUTURE DIRECTIONS: Current research could focus on elucidating the wide array of reactions between ascorbate and reactive species, namely ROS, reactive nitrogen species (RNS) as well as reactive sulfide species (RSS), and their intracellular molecular targets. Unraveling these mechanisms could allow researchers to assess what could be the optimal combination of ascorbate with standard treatments.
  6. J BUON. 2021 May-Jun;26(3):26(3): 924-931
      PURPOSE: Gastric cancer, which is derived from gastric mucosal epithelial cells, is a representative solid tumour, and more than 1 million cases are diagnosed worldwide each year. However, treatment methods and therapeutics for gastric cancer are limited, and further research is needed to develop novel strategies.METHODS: In this experiment, we studied the effect of catalpol from the extract of Dihuang from traditional Chinese medicine on gastric cancer cells.
    RESULTS: The results showed that catalpol led to a dose-dependent reduction in gastric cancer cell proliferation. When the promotion of autophagy by catalpol was inhibited, the proapoptotic effects of catalpol on gastric cancer cells were enhanced. Bax, an apoptosis-related marker, was upregulated in catalpol-treated cells, and its expression was increased in the group treated with catalpol in combination with an inhibitor compared to the group treated with catalpol alone. Opposite results were obtained with BCL-2 inhibition. Flow cytometry showed that apoptosis rates were higher in cells treated with a combination of autophagy inhibitors. Accumulation of reactive oxygen species (ROS) in gastric cancer cells showed the group treated with the combination of catalpol and an inhibitor enhanced ROS production. Transwell assays showed that catalpol plus autophagy inhibitors exerted a stronger inhibitory effect on the migration ability of AGS cells than catalpol alone.
    CONCLUSIONS: In summary, the above results indicate that inhibition of catalpol-induced autophagy could better promote the apoptosis of gastric cancer cells.
  7. Am J Cancer Res. 2021 ;11(6): 3039-3054
      Colon cancer (CC) is a prevalent malignancy worldwide. Approaches to specifically induce tumor cell death have historically been a popular research topic. Honokiol (HNK), which exhibits highly efficient and specific anticancer effects, is a biphenolic compound found in Magnolia grandiflora. In the present study, we aim to study the effect of HNK on CC cells and elucidate the potential underlying mechanisms. Seven CC cell lines (RKO, HCT116, SW48, HT29, LS174T, HCT8, and SW480) were used. Cells were exposed to HNK and subjected to a series of assays to evaluate characteristics such as cellular activity, reactive oxygen species (ROS) levels and ferroptosis-related protein expression levels. Lentiviral transduction was also used to verify molecular mechanisms in vivo and in vitro. We here observed that HNK reduced the viability of CC cell lines by increasing ROS and Fe2+ levels. Transmission electron microscopy revealed HNK-induced changes in mitochondrial morphology. HNK decreased the activity of Glutathione Peroxidase 4 (GPX4) but did not affect system Xc-. Thus, our datas indicated that HNK can induce ferroptosis in CC cells by reducing the activity of GPX4. As a potential therapeutic drug, HNK showed good anticancer effects through diverse signal transduction mechanisms and multiple pathways.
    Keywords:  GPX4; Honokiol (HNK); colon cancer (CC); ferroptosis; reactive oxygen species (ROS)
  8. Int J Nanomedicine. 2021 ;16 4559-4577
      Purpose: Reactive oxygen species (ROS) are a group of signaling biomolecules that play important roles in the cell cycle. When intracellular ROS homeostasis is disrupted, it can induce cellular necrosis and apoptosis. It is desirable to effectively cascade-amplifying ROS generation and weaken antioxidant defense for disrupting ROS homeostasis in tumor microenvironment (TME), which has been recognized as a novel and ideal antitumor strategy. Multifunctional nanozymes are highly promising agents for ROS-mediated therapy.Methods: This study constructed a novel theranostic nanoagent based on PEG@Cu2-xS@Ce6 nanozymes (PCCNs) through a facile one-step hydrothermal method. We systematically investigated the photodynamic therapy (PDT)/photothermal therapy (PTT) properties, catalytic therapy (CTT) and glutathione (GSH) depletion activities of PCCNs, antitumor efficacy induced by PCCNs in vitro and in vivo.
    Results: PCCNs generate singlet oxygen (1O2) with laser (660 nm) irradiation and use catalytic reactions to produce hydroxyl radical (•OH). Moreover, PCCNs show the high photothermal performance under NIR II 1064-nm laser irradiation, which can enhance CTT/PDT efficiencies to increase ROS generation. The properties of O2 evolution and GSH consumption of PCCNs achieve hypoxia-relieved PDT and destroy cellular antioxidant defense system respectively. The excellent antitumor efficacy in 4T1 tumor-bearing mice of PCCNs is achieved through disrupting ROS homeostasis-involved therapy under the guidance of photothermal/photoacoustic imaging.
    Conclusion: Our study provides a proof of concept of "all-in-one" nanozymes to eliminate tumors via disrupting ROS homeostasis.
    Keywords:  ROS homeostasis; catalytic therapy; nanozyme; photodynamic/photothermal therapy; photothermal/photoacoustic imaging; tumor microenvironment
  9. Biomaterials. 2021 Jul 07. pii: S0142-9612(21)00368-9. [Epub ahead of print]276 121012
      Recent studies have indicated that cancer treatment based on immunotherapy alone is not viable. Combined treatment with other strategies is required to achieve the expected therapeutic effect. Reactive oxygen species (ROS) play an important role in regulating cancer cells and the tumor microenvironment, even in immune cells. However, rigorous regulation of the ROS level within the entire tumor tissue is difficult, limiting the application of ROS in cancer therapy. Therefore, we design an early phago-/endosome-escaping micelle that can release platinum-based drugs into the cytoplasm of macrophages and cancer cells, thereby enhancing the ROS levels of the entire tumor tissue; inducing apoptosis of cancer cells, down-regulation of CD47 expression of cancer cells, polarization of M1 macrophages, and phagocytosis of cancer cells by M1 macrophages; and achieving the dual effect of chemotherapy and macrophage-mediated immunotherapy.
    Keywords:  Chemotherapy; Immunotherapy; Phago-/endosomal escape; Polymeric micelles; Tumor-associated macrophages
  10. Oncol Lett. 2021 Aug;22(2): 631
      Breast cancer is one of the most frequently diagnosed cancers amongst women; however, there is currently no effective treatment. Natural compounds are considered to contribute to cancer prevention and have a pivotal role in modulating apoptosis. Rosmanol is a phenolic diterpene compound with antioxidant and anti-inflammatory properties. In the present study, the effects of Rosmanol on breast cancer cell proliferation/apoptosis were investigated, and it was demonstrated that it inhibited the proliferation of MCF-7 and MDA-MB 231 cells but did not have a significant effect on normal human breast MCF-10A cells. In addition, the apoptotic process was accelerated by Rosmanol, through mitochondrial pathways and reactive oxygen species (ROS) production caused by DNA damage, which function further demonstrated by the attenuation and addition of the ROS inhibitor, N-acetyl-cysteine. It was also demonstrated that Rosmanol accelerated cell apoptosis, and arrested breast cancer cells in the S phase. Moreover, Rosmanol inhibited proliferation and promoted apoptosis of cancer cells via the inhibition of ERK and STAT3 signals, attributable to the increase in p-p38, the overexpression of protein inhibitor of activated STAT3, and the decrease in PI3K/AKT, ERK and JAK2/STAT3.
    Keywords:  JAK2; Rosmanol; STAT3; apoptosis
  11. Free Radic Biol Med. 2021 Jul 13. pii: S0891-5849(21)00418-4. [Epub ahead of print]
      Reactive oxygen species (ROS)/reactive nitrogen species (RNS)-mediated ferroptosis becomes a novel effective target for anti-cancer treatment. In the present study, we tested the hypothesis that 18-β-glycyrrhetinic acid (GA), an active compound from medicinal herbal Licorice, could induce the production of ROS/RNS, increase lipid peroxidation and trigger ferroptosis in MDA-MB-231 triple negative breast cancer cells. To confirm the GA's anti-cancer effects, we detected cell viability, apoptosis and ferroptosis in the MDA-MB-231 cells. To explore the effects of GA on inducing ferroptosis, we measured ROS/RNS production, lipid peroxidation, ferrous ion, glutathione (GSH), System Xc-, GPX4, glutathione peroxidases (GPX), NADPH oxidase and iNOS in the MDA-MB-231 cells. The major discoveries are included as below: (1) GA treatment selectively decreased cell viability and induced ferroptosis companied with the increased lipid peroxidation and ferrous ion in the MDA-MB-231 triple negative breast cancer cells. Iron chelator deferoxamine mesylate (DFO) and ferroptosis inhibitor Ferrostatin-1 abolished the effects of GA. (2) GA treatment up-regulated the expression and activity of NADPH oxidase and iNOS, and increased ROS/RNS productions (O2•-, •OH, NO and ONOO-) in the MDA-MB-231 cells; (3) GA down-regulated the expression of SLC7A11 of System Xc-, decreased glutathione (GSH) level and inhibited GPX activity. Taken together, GA could promote the productions of ROS and RNS via activating NADPH oxidases and iNOS, and decreasing GSH and GPX activity, subsequently aggravating lipid peroxidation and triggering ferroptosis in triple-negative breast cancer cells.
    Keywords:  Breast cancer; Ferroptosis; Glycyrrhetinic acid; NADPH oxidase; RNS; ROS; iNOS
  12. Oxid Med Cell Longev. 2021 ;2021 5549047
      Current studies on tumor progression focus on the roles of cytokines in the tumor microenvironment (TME), and recent research shows that transforming growth factor-β1 (TGF-β1) released from TME plays a pivotal role in tumor development and malignant transformation. The alteration in cellular metabolism is a hallmark of cancer, which not only provides cancer cells with ATP for fuel cellular reactions, but also generates metabolic intermediates for the synthesis of essential cellular ingredients, to support cell proliferation, migration, and invasion. Interestingly, we found a distinct metabolic change during TGF-β1-induced epithelial-mesenchymal transition (EMT) in glioblastoma cells. Indeed, TGF-β1 participates in metabolic reprogramming, and the molecular basis is still not well understood. NADPH oxidases 4 (NOX4), a member of the Nox family, also plays a key role in the biological effects of glioblastoma. However, the relationship between NOX4, TGF-β1, and cellular metabolic changes during EMT in glioblastoma remains obscure. Here, our findings demonstrated that TGF-β1 upregulated NOX4 expression accompanied by reactive oxygen species (ROS) through Smad-dependent signaling and then induced hypoxia-inducible factor 1α (HIF-1α) overexpression and nuclear accumulation resulting in metabolic reprogramming and promoting EMT. Besides, inhibition of glycolysis reversed EMT suggesting a causal relationship between TGF-β1-induced metabolic changes and tumorigenesis. Moreover, TGF-β1-induced metabolic reprogramming and EMT which modulated by NOX4/ROS were blocked when the phosphoinositide3-kinase (PI3K)/AKT/HIF-1α signaling pathways were inhibited. In conclusion, these suggest that NOX4/ROS induction by TGF-β1 can be one of the main mechanisms mediating the metabolic reprogramming during EMT of glioblastoma cells and provide promising strategies for cancer therapy.
  13. Chembiochem. 2021 Jul 12.
      The identification of growth inhibitory compounds with the ability to selectively target the cellular oxygenation state may be of therapeutic interest. Here, a phenotypic screen of a covalent fragment library revealed diverse compounds containing propiolamide warheads with selective toxicity for liver cancer cells in normoxic conditions. Target identification and validation through CETSA and direct pulldown experiments demonstrated that several compounds target glutathione peroxidase 4 (GPX4) and induce ferroptotic cell death. Although being an oxidative cell death mechanism, ferroptosis can be induced also under hypoxic conditions. Prompted by the selective toxicity discovered in the screen, we mapped the oxygen-dependence of several ferroptosis-inducing compounds across three different cell lines. These studies revealed combinations with notable reductions in sensitivity under hypoxic conditions. These observations are mechanistically interesting and may be relevant for the use of ferroptosis-inducers as anti-cancer agents.
    Keywords:  Covalent fragments; GPX4; Hypoxia; Phenotypic screening; ferroptosis
  14. Pathol Oncol Res. 2021 ;27 594299
      Glioblastoma is one of the most aggressive primary brain tumors with few treatment strategies. β-Elemene is a sesquiterpene known to have broad spectrum antitumor activity against various cancers. However, the signaling pathways involved in β-elemene induced apoptosis of glioblastoma cells remains poorly understood. In this study, we reported that β-elemene exhibited antiproliferative activity on U87 and SHG-44 cells, and induced cell death through induction of apoptosis. Incubation of these cells with β-elemene led to the activation of caspase-3 and generation of reactive oxygen species (ROS). Western blot assay showed that β-elemene suppressed phosphorylation of STAT3, and subsequently down-regulated the activation of p-JAK2 and p-Src. Moreover, pre-incubation of cells with ROS inhibitor N-acetyl-L-cysteine (NAC) significantly reversed β-elemene-mediated apoptosis effect and down-regulation of JAK2/Src-STAT3 signaling pathway. Overall, our findings implied that generation of ROS and suppression of STAT3 signaling pathway is critical for the apoptotic activity of β-elemene in glioblastoma cells.
    Keywords:  ROS; apoptosis; glioblastoma; stat3; β-elemene
  15. Nanomedicine. 2021 Jul 10. pii: S1549-9634(21)00083-6. [Epub ahead of print] 102440
      Lately, chemotherapy and photodynamic therapy (PDT) synergistic therapy has become a promising anti-cancer treatment mean. However, the hypoxia in tumor leads to huge impediments to the oxygen-dependent PDT effects. In this work, a multifunctional nanoplatform (TUDMP) based a multivariable porphyrin-nMOFs core and a manganese dioxide (MnO2) shell was prepared for relieving tumor hypoxia and enhancing chemo-photodynamic synergistic therapy performance. The obtained TUDMP nanoplatform could effectively catalyze the hydrolysis of hydrogen peroxide to generate oxygen and also lead to consumption of antioxidant GSH, thereby facilitates the production of cytotoxic reactive oxygen species (ROS) by photosensitizer under laser irradiation. More importantly, the decomposition of the MnO2 shell would further promote the release of the loaded doxorubicin (DOX), and thus an efficient chemo-PDT synergistic therapy was realized. Both in vitro and in vivo experimental results demonstrated the oxygen self-sufficient multifunctional nanoplatform could exhibited significantly enhanced anticancer efficiencies compared with chemotherapy or PDT alone.
    Keywords:  Metal–organic frameworks; Photodynamic therapy; Reactive oxygen species; Synergistic therapy; Tumor hypoxia
  16. J Exp Clin Cancer Res. 2021 Jul 12. 40(1): 228
      BACKGROUND: Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor in adults, characterized by a poor prognosis mainly due to recurrence and therapeutic resistance. It has been widely demonstrated that glioblastoma stem-like cells (GSCs), a subpopulation of tumor cells endowed with stem-like properties is responsible for tumor maintenance and progression. Moreover, it has been demonstrated that GSCs contribute to GBM-associated neovascularization processes, through different mechanisms including the transdifferentiation into GSC-derived endothelial cells (GdECs).METHODS: In order to identify druggable cancer-related pathways in GBM, we assessed the effect of a selection of 349 compounds on both GSCs and GdECs and we selected elesclomol (STA-4783) as the most effective agent in inducing cell death on both GSC and GdEC lines tested.
    RESULTS: Elesclomol has been already described to be a potent oxidative stress inducer. In depth investigation of the molecular mechanisms underlying GSC and GdEC response to elesclomol, confirmed that this compound induces a strong increase in mitochondrial reactive oxygen species (ROS) in both GSCs and GdECs ultimately leading to a non-apoptotic copper-dependent cell death. Moreover, combined in vitro treatment with elesclomol and the alkylating agent temozolomide (TMZ) enhanced the cytotoxicity compared to TMZ alone. Finally, we used our experimental model of mouse brain xenografts to test the combination of elesclomol and TMZ and confirmed their efficacy in vivo.
    CONCLUSIONS: Our results support further evaluation of therapeutics targeting oxidative stress such as elesclomol with the aim of satisfying the high unmet medical need in the management of GBM.
    Keywords:  Cancer stem cells; Elesclomol; Glioblastoma; Oxidative stress
  17. Biomed Pharmacother. 2021 Jul;pii: S0753-3322(21)00489-3. [Epub ahead of print]139 111707
      Invasive ductal carcinoma (IDC) is the most recurrent cancer, accounting for 80% of all breast cancers worldwide. Originating from the milk duct, it eventually invades the fibrous tissue of the breast outside the duct, proliferation takes 1-2 months for each division. Quinacrine (QC), an FDA-approved small molecule, has been shown to have anti-cancer activity in numerous cancerous cell lines through diverse pathways; ultimately leading to cell death. Here, we have investigated the mode of action of QC in MCF7 cells. This study demonstrated the modulation of cellular cytoskeleton, such as the formation of distinct filopodial and lamellipodial structures and spikes, through the regulation of small-GTPases. We also observed that QC induces a signaling cascade by inducing apoptotic cell death by increasing ROS generation and altering HSP70 expression; which presumably involves ERK regulation. Our findings show that QC could be an attractive chemotherapeutic agent having a "shotgun" nature with potential of inducing different signaling pathways leading to apoptotic cell death. This opens new avenues for research on developing QC as an effective therapeutic agent for the treatment of invasive ductal carcinomas.
    Keywords:  Cytochrome-c; HSP70; Invasive ductal carcinoma; P-ERK; Quinacrine; Small-GTPases
  18. Nanotechnology. 2021 Jul 16.
      The urgency for new materials in oncology is immediate. In this study we have developed the g-C3N4, a graphitic-like structure formed by periodically linked tris-s-triazine units. The g-C3N4 has been synthesized by a simple and fast thermal process. XRD has shown the formation of the crystalline sheet with a compacted structure. The graphite-like structure and the functional groups have been shown by Raman and FTIR spectroscopy. TEM image and AFM revealed the porous composed of five or six C-N layers stacked. DRS and Photoluminescence analyses confirmed the structure with band gap of 2.87 eV and emission band at 448 nm in different wavelengths excitation conditions. The biological results showed inhibitory effect on: cancer cell lines and non-toxic effect in normal cell lines. To the best of our knowledge, this is the first work demonstrating the cytotoxic effects of 2D g-C3N4 in a cancer cell line, without any external or synergistic influence. The biodistribution/tissue accumulation showed that g-C3N4 present a tendency to accumulation on the lung in the first 2 hours, but after 24 hours the profile of the biodistribution change and it is found mainly in the liver. Thus, 2D-g-C3N4 showed great potential for the treatment of several cancer types.
    Keywords:  2D g-C3N4; Cytotoxic effect; Graphite Carbon nitride; nanomedicine; theranostic; therapy
  19. Onco Targets Ther. 2021 ;14 4061-4075
      Background: Lenalidomide, an immunomodulatory drug (IMiD), is an effective therapy for the treatment of multiple myeloma (MM). However, prolonged treatment may be accompanied by toxicity, second primary malignancies, and drug resistance. There is an inherent vulnerability in MM cells that high rates of immunoglobulin synthesis resulting in the high level of reactive oxygen species (ROS). This provides a therapeutic potential for MM.Materials and Methods: The intracellular ROS levels, H2O2 production and glutathione (GSH) levels were measured using detection kit. Cell viability was evaluated using cell-counting kit-8 (CCK-8) and soft agar colony formation assay. Apoptosis was determined in whole living cells using flow cytometry. Chidamide and its anti-myeloma efficacy in combination with lenalidomide were characterized in MM cell lines in vitro and in a mouse xenograft model. Moreover, Western blotting, immunofluorescence and immunohistochemical studies were performed.
    Results: ROS levels increased in a time- and dose-dependent manner with chidamide treatment. Moreover, the GSH levels were decreased and the mRNA level of SLC7A11 downregulated after chidamide treatment. The co-treatment with chidamide and lenalidomide increased apoptosis and proliferation inhibition, with combination index (CI) in the synergistic range (0.2-0.5) using the Chou-Talalay method. The cooperative anti-myeloma efficacy was confirmed in the murine model, and immunohistochemical studies also supported this potentiation. Chidamide enhanced the effect of lenalidomide-induced degradation of IKZF1 and IKZF3 by elevating H2O2. In addition, co-treatment with chidamide and lenalidomide increased biomarkers of caspase and DNA damage.
    Conclusion: Elevated ROS production may constitute a potential biochemical basis for anti-myeloma effects of chidamide plus lenalidomide. The results of this study confirm the synergistic effect of chidamide and lenalidomide against MM and provide a promising therapeutic strategy for MM.
    Keywords:  chidamide; lenalidomide; multiple myeloma; reactive oxygen species
  20. Commun Biol. 2021 Jul 13. 4(1): 865
      A single-nucleotide polymorphism of neutrophil cytosolic factor 1 (Ncf1), leading to an impaired generation of reactive oxygen species (ROS), is a causative genetic factor for autoimmune disease. To study a possible tumor protection effect by the Ncf1 mutation in a manner dependent on cell types, we used experimental mouse models of lung colonization assay by B16F10 melanoma cells. We observed fewer tumor foci in Ncf1 mutant mice, irrespective of αβT, γδT, B-cell deficiencies, or of a functional Ncf1 expression in CD68-positive monocytes/macrophages. The susceptibility to tumor colonization was restored by the human S100A8 (MRP8) promoter directing a functional Ncf1 expression to granulocytes. This effect was associated with an increase of both ROS and interleukin 1 beta (IL-1β) production from lung neutrophils. Moreover, neutrophil depletion by anti-Ly6G antibodies increased tumor colonization in wild type but failed in the Ncf1 mutant mice. In conclusion, tumor colonization is counteracted by ROS-activated and IL-1β-secreting tissue neutrophils.
  21. Nano Lett. 2021 Jul 13.
      The development of novel sonosensitizers with outstanding reactive oxygen (ROS) generation capacity and great biocompatibility poses a significant challenge for the clinical practice of sonodynamic therapy (SDT). In this work, hemoglobin (Hb) with natural metalloporphyrin was first shown to possess great potential as a sonosensitizer. Compared with traditional organic sonosensitizers, Hb had satisfactory sono-sensitizing efficiency because four the porphyrin molecules were separated by four polypeptide chains. This effectively avoided the problem of low ROS quantum yield caused by the stacking of hydrophobic porphyrins. Meanwhile, Hb is an efficient and safe oxygen carrier that may release O2 at hypoxic tumors site, which improved tumor oxygenation and subsequently enhanced SDT efficacy. Therefore, Hb was integrated with zeolitic imidazolate framework 8 (ZIF-8) to form a nanoplatform that demonstrated a potent suppression effect on deep-seated tumors under ultrasound irradiation.
    Keywords:  ROS; hemoglobin; hypoxia; mitochondria-involved apoptosis; sonodynamic therapy
  22. Biomater Sci. 2021 Jul 16.
      As a common feature of the tumor microenvironment (TME), hypoxia significantly impedes the effects of photodynamic therapy. Moreover, for tumor combination therapy, smart responsive and well-designed nanocarriers are highlighted to co-deliver different therapeutics, enhance drug delivery into target sites, and realize stimuli-responsive drug release. Herein, oxygen- and bubble-generating polymersomes (FIMPs) were developed for tumor-targeted and enhanced photothermal-photodynamic combination therapy. FIMPs efficiently co-encapsulated manganese dioxide (MnO2) and the hydrophobic photosensitizer indocyanine green (ICG) within the hydrophobic membrane as well as the bubble-generating reagent NH4HCO3 in the internal cavity of the vesicles, and achieved pH/temperature/reduction multiple responsiveness. The CO2 bubbles generated from the decomposition of NH4HCO3 via laser irradiation or acidic environment and the cleavage of the copolymer disulfide bond in the reducing TME would destroy the vesicle structure for triggering drug release. In addition, oxygen can be produced to overcome tumor hypoxia through the high reaction activity of MnO2 with endogenous H2O2. In vitro studies have shown that FIMPs achieved good photothermal conversion efficiency, promoted the generation of oxygen and reactive oxygen species (ROS), and thus effectively killed tumor cells. In vivo studies indicated that FIMPs effectively overcome the hypoxic microenvironment within tumors and significantly inhibit tumor growth with good biocompatibility. The rationally designed oxygen- and bubble-generating polymersomes have great potential to overcome the tumor hypoxia limitations for enhancing the photothermal-photodynamic combination therapeutic effect.
  23. Biomater Sci. 2021 Jul 16.
      Nitric oxide (NO) gas treatment offers a promising strategy for tumor therapy; however, its practical application is still limited due to its poor efficacy and biotoxicity which were caused by gas leakage during blood delivery. Herein, a nano-platform (CMH-OBN) composed of chlorin e6-melanin-hyaluronic acid nanoparticles (Ce6-MNP-HA, CMH) and oxidized bletilla striata polysaccharide microcapsules (Oxi-BSP) carrying NO donors was prepared for responsive and cascaded release of NO, reactive oxygen species (ROS) and its secondary metabolite reactive nitrogen species (RNS) in tumor sites. Melanin not only endowed CMH with good photothermal properties, but also helped Ce6 to produce a large number of ROS under near-infrared (NIR) irradiation. OBN microcapsules, which were sensitive to ROS, can release NO donors under the stimulation of ROS released by CMH nanoparticles under NIR irradiation and can further release NO in the tumor microenvironment (TME) with high expression of glutathione (GSH). NO could further up-regulate soluble guanylate cyclase-cyclic guanosine monophosphate (sGC-cGMP) signal pathways to relieve hypoxia, thus further enhancing the photodynamic therapy (PDT). Moreover, the cascaded release of ROS and NO could produce RNS with higher lethality, which could sequentially initiate the cellular apoptotic procedure and promote immunotherapy by activating T cells at the tumor sites. More interestingly, the CMH-OBN nano-platform could supply magnetic resonance imaging (MRI) and infrared photothermal imaging guidance for tumor therapy. In conclusion, the development of a CMH-OBN nano-platform provides a satisfactory demonstration by combining NO therapy with photothermal therapy (PTT), PDT and immunotherapy for the treatment of cancer.
  24. Free Radic Biol Med. 2021 Jul 06. pii: S0891-5849(21)00404-4. [Epub ahead of print]172 590-603
      Tumor microenvironments are characterized not only in terms of chemical composition, but also by physical properties such as stiffness, which influences morphology, proliferation, and fate of tumor cells. However, the underlying mechanisms between matrix stiffness and the apoptosis-autophagy balance remain largely unexplored. In this study, we cultured human breast cancer MDA-MB-231 cells on rigid (57 kPa), stiff (38 kPa) or soft (10 kPa) substrates and demonstrated that increasing autophagy levels and autophagic flux in the cells cultured on soft substrates partly attenuated soft substrate-induced apoptosis. Mechanistically, this protective autophagy is regulated by intracellular reactive oxygen species (ROS) accumulation, which triggers the downstream signals of JNK, Bcl-2 and Beclin-1. More importantly, soft substrate-induced activation of ROS/JNK signaling promotes cell apoptosis through the mitochondrial pathway, whereas it increases protective autophagy by suppressing the interaction of Bcl-2 and Beclin-1. Taken together, our data suggest that JNK is the mediator of soft substrate-induced breast cancer cell apoptosis and autophagy which is likely to be the mechanism that partly attenuates mitochondrial apoptosis. This study provides new insights into the molecular mechanism by which autophagy plays a protective role against soft substrate-induced apoptosis in human breast cancer cells.
    Keywords:  Apoptosis; Autophagy; JNK; Matrix stiffness; ROS