Role of glutathione in cancer progression and chemoresistance

Near-infrared fluorescent probes for the detection of glutathione and their application in the fluorescence imaging of living cells and tumor-bearing mice

Two new cyanine-based fluorescent probes 1 and 2 have been developed. Probe 1 bears two cyanine units in a single molecule, and probe 2 contains a bis(trifluoromethyl)benzenethiol moiety. Both are non-fluorescent. The addition of intracellular glutathione (GSH) significantly enhanced the NIR fluorescence of the two probes. Both probes were used to image varying amounts of GSH in living cells. In tumor bearing mice, the in vivo fluorescence intensity of both probes was higher in tumors, where GSH is overexpressed, than in normal tissues. These results suggest that these new fluorogenic probes have potential for GSH-targeting diagnostic imaging.

Crude Flavonoid Extract of Medicinal Herb Zingibar officinale Inhibits Proliferation and Induces Apoptosis in Hepatocellular Carcinoma Cells

There is an urgent need to improve the clinical management of hepatocellular carcinoma (HCC), one of the most common causes of global cancer-related deaths. Zingibar officinale is a medicinal herb used throughout history for both culinary and medicinal purposes. It has antioxidant, anticarcinogenic, and free radical scavenging properties. Previously, we proved that the crude flavonoid extract of Z. officinale (CFEZO) inhibited growth and induced apoptosis in several cancer cell lines. However, the effect of the CFEZO on an HCC cell line has not yet been evaluated. In this study, we explored the anticancer activity of CFEZO against an HCC cell line, HepG2. CFEZO significantly inhibited proliferation and induced apoptosis in HepG2 cells. Typical apoptotic morphological and biochemical changes, including cell shrinkage and detachment, nuclear condensation and fragmentation, DNA degradation, and comet tail formation, were observed after treatments with CFEZO. The apoptogenic activity of CFEZO involved induction of ROS, depletion of GSH, disruption of the mitochondrial membrane potential, activation of caspase 3/9, and an increase in the Bax/Bcl-2 ratio. CFEZO treatments induced upregulation of p53 and p21 expression and downregulation of cyclin D1 and cyclin-dependent kinase-4 expression, which were accompanied by G2/M phase arrest. These findings suggest that CFEZO provides a useful foundation for studying and developing novel chemotherapeutic agents for the treatment of HCC.

Iron and thiol redox signaling in cancer: An exquisite balance to escape ferroptosis

Epidemiological data indicate a constant worldwide increase in cancer mortality, although the age of onset is increasing. Recent accumulation of genomic data on human cancer via next-generation sequencing confirmed that cancer is a disease of genome alteration. In many cancers, the Nrf2 transcription system is activated via mutations either in Nrf2 or Keap1 ubiquitin ligase, leading to persistent activation of the genes with antioxidative functions. Furthermore, deep sequencing of passenger mutations is clarifying responsible cancer causative agent(s) in each case, including aging, APOBEC activation, smoking and UV. Therefore, it is most likely that oxidative stress is the principal initiating factor in carcinogenesis, with the involvement of two essential molecules for life, iron and oxygen. There is evidence based on epidemiological and animal studies that excess iron is a major risk for carcinogenesis, suggesting the importance of ferroptosis-resistance. Microscopic visualization of catalytic Fe(II) has recently become available. Although catalytic Fe(II) is largely present in lysosomes, proliferating cells harbor catalytic Fe(II) also in the cytosol and mitochondria. Oxidative stress catalyzed by Fe(II) is counteracted by thiol systems at different functional levels. Nitric oxide, carbon monoxide and hydrogen (per)sulfide modulate these reactions. Mitochondria generate not only energy but also heme/iron sulfur cluster cofactors and remain mostly dysfunctional in cancer cells, leading to Warburg effects. Cancer cells are under persistent oxidative stress with a delicate balance between catalytic iron and thiols, thereby escaping ferroptosis. Thus, high-dose L-ascorbate and non-thermal plasma as well as glucose/glutamine deprivation may provide additional benefits as cancer therapies over preexisting therapeutics.

ROS-modulated therapeutic approaches in cancer treatment

PURPOSE

Reactive oxygen species (ROS) are produced in cancer cells as a result of increased metabolic rate, dysfunction of mitochondria, elevated cell signaling, expression of oncogenes and increased peroxisome activities. Certain level of ROS is required by cancer cells, above or below which lead to cytotoxicity in cancer cells. This biochemical aspect can be exploited to develop novel therapeutic agents to preferentially and selectively target cancer cells.

METHODS

We searched various electronic databases including PubMed, Web of Science, and Google Scholar for peer-reviewed english-language articles. Selected articles ranging from research papers, clinical studies, and review articles on the ROS production in living systems, its role in cancer development and cancer treatment, and the role of microbiota in ROS-dependent cancer therapy were analyzed.

RESULTS

This review highlights oxidative stress in tumors, underlying mechanisms of different relationships of ROS and cancer cells, different ROS-mediated therapeutic strategies and the emerging role of microbiota in cancer therapy.

CONCLUSION

Cancer cells exhibit increased ROS stress and disturbed redox homeostasis which lead to ROS adaptations. ROS-dependent anticancer therapies including ROS scavenging anticancer therapy and ROS boosting anticancer therapy have shown promising results in vitro as well as in vivo. In addition, response to cancer therapy is modulated by the human microbiota which plays a critical role in systemic body functions.

MicroRNA-34a Encapsulated in Hyaluronic Acid Nanoparticles Induces Epigenetic Changes with Altered Mitochondrial Bioenergetics and Apoptosis in Non-Small-Cell Lung Cancer Cells

Therapies targeting epigenetic changes for cancer treatment are in Phase I/II trials; however, all of these target only nuclear DNA. Emerging evidence suggests presence of methylation marks on mitochondrial DNA (mtDNA); but their contribution in cancer is unidentified. Expression of genes encoded on mtDNA are altered in cancer cells, along with increased glycolytic flux. Such glycolytic flux and elevated reactive oxygen species is supported by increased antioxidant; glutathione. MicroRNA-34a can translocate to mitochondria, mediate downstream apoptotic effects of tumor suppressor P53, and inhibit the antioxidant response element Nrf-2, resulting in depleted glutathione levels. Based on such strong rationale, we encapsulated microRNA-34a in our well-established Hyaluronic-Acid nanoparticles and delivered to cisplatin-sensitive and cisplatin-resistant A549-lung adenocarcinoma cells. Successful delivery and uptake in cells resulted in altered ATP levels, decreased glycolytic flux, Nrf-2 and glutathione levels, ultimately resulting in caspase-3 activation and apoptosis. Most important were the concurrent underlying molecular changes in epigenetic status of D-loop on the mtDNA and transcription of mtDNA-encoded genes. Although preliminary, we provide a novel therapeutic approach in form of altered mitochondrial bioenergetics and redox status of cancer cells with underlying changes in epigenetic status of mtDNA that can subsequently results in induction of cancer cell apoptosis.

Overexpression of MSK1 is associated with tumor aggressiveness and poor prognosis in colorectal cancer

BACKGROUND/AIMS

Mitogen- and stress-activated protein kinase 1 (MSK1) has recently been implicated in cell proliferation and neoplastic transformation. However, the involvement of MSK1 in colorectal cancer (CRC) has not been addressed. This study aimed to evaluate the expression and potential functions of MSK1 in CRC.

METHODS

The MSK1 expression was investigated by immunohistochemistry, western blot and reverse transcription-polymerase chain reaction. The associations between clinicopathological characteristics and MSK1 expression were assessed. Kaplan-Meier analysis and Cox regression models were carried out. CRC cells with MSK1 knockdown or overexpression were generated. A range of experiments were performed to demonstrate MSK1's role in CRC.

RESULTS

MSK1 was overexpressed in 148 out of 329 CRC patients. CRC patients with high MSK1 expression had shorter overall survival than those with low MSK1 (P=0.033), especially among patients with stage III tumors (P=0.005). Knockdown of MSK1 in CRC cells suppressed cell proliferation, anchorage-independent growth, migration and invasion, and promoted 5-fluorouracil chemosensitivity and intracellular NADP⁺/NADPH ratio. However, overexpression of MSK1 had the opposite effects.

CONCLUSIONS

Overexpression of MSK1 is associated with poor prognosis in CRC and is connected to tumor aggressiveness. MSK1 is a potential target for new therapies and a candidate of biomarker for prognosis.

Detection of Metastatic Breast and Thyroid Cancer in Lymph Nodes by Desorption Electrospray Ionization Mass Spectrometry Imaging

Ambient ionization mass spectrometry has been widely applied to image lipids and metabolites in primary cancer tissues with the purpose of detecting and understanding metabolic changes associated with cancer development and progression. Here, we report the use of desorption electrospray ionization mass spectrometry (DESI-MS) to image metastatic breast and thyroid cancer in human lymph node tissues. Our results show clear alterations in lipid and metabolite distributions detected in the mass spectra profiles from 42 samples of metastatic thyroid tumors, metastatic breast tumors, and normal lymph node tissues. 2D DESI-MS ion images of selected molecular species allowed discrimination and visualization of specific histologic features within tissue sections, including regions of metastatic cancer, adjacent normal lymph node, and fibrosis or adipose tissues, which strongly correlated with pathologic findings. In thyroid cancer metastasis, increased relative abundances of ceramides and glycerophosphoinisitols were observed. In breast cancer metastasis, increased relative abundances of various fatty acids and specific glycerophospholipids were seen. Trends in the alterations in fatty acyl chain composition of lipid species were also observed through detailed mass spectra evaluation and chemical identification of molecular species. The results obtained demonstrate DESI-MSI as a potential clinical tool for the detection of breast and thyroid cancer metastasis in lymph nodes, although further validation is needed. Graphical Abstract Desorption electrospray ionization mass spectrometry imaging is used to differentiate metastatic cancer from adjacent lymph node tissue.

Towards Hypoxia-responsive Drug-eluting Embolization Beads

Drug release from chemoembolization microspheres stimulated by the presence of a chemically reducing environment may provide benefits for targeting drug resistant and metastatic hypoxic tumours. A water-soluble disulfide-based bifunctional cross-linker bis(acryloyl)-(l)-cystine (BALC) was synthesised, characterised and incorporated into a modified poly(vinyl) alcohol (PVA) hydrogel beads at varying concentrations using reverse suspension polymerisation. The beads were characterised to confirm the amount of cross-linker within each formulation and its effects on the bead properties. Elemental and UV/visible spectroscopic analysis confirmed the incorporation of BALC within the beads and sizing studies showed that in the presence of a reducing agent, all bead formulations increased in mean diameter. The BALC beads could be loaded with doxorubicin hydrochloride and amounts in excess of 300mg of drug per mL of hydrated beads could be achieved but required conversion of the carboxylic acid groups of the BALC to their sodium carboxylate salt forms. Elution of doxorubicin from the beads demonstrated a controlled release via ionic exchange. Some formulations exhibited an increase in size and release of drug in the presence of a reducing agent, and therefore demonstrated the ability to respond to an in vitro reducing environment.

Metabolic Portraits of Breast Cancer by HR MAS MR Spectroscopy of Intact Tissue Samples

Despite progress in early detection and therapeutic strategies, breast cancer remains the second leading cause of cancer-related death among women globally. Due to the heterogeneity and complexity of tumor biology, breast cancer patients with similar diagnosis might have different prognosis and response to treatment. Thus, deeper understanding of individual tumor properties is necessary. Cancer cells must be able to convert nutrients to biomass while maintaining energy production, which requires reprogramming of central metabolic processes in the cells. This phenomenon is increasingly recognized as a potential target for treatment, but also as a source for biomarkers that can be used for prognosis, risk stratification and therapy monitoring. Magnetic resonance (MR) metabolomics is a widely used approach in translational research, aiming to identify clinically relevant metabolic biomarkers or generate novel understanding of the molecular biology in tumors. Ex vivo proton high-resolution magic angle spinning (HR MAS) MR spectroscopy is widely used to study central metabolic processes in a non-destructive manner. Here we review the current status for HR MAS MR spectroscopy findings in breast cancer in relation to glucose, amino acid and choline metabolism.

HO-1 Induction in Cancer Progression: A Matter of Cell Adaptation

The upregulation of heme oxygenase-1 (HO-1) is one of the most important mechanisms of cell adaptation to stress. Indeed, the redox sensitive transcription factor Nrf2 is the pivotal regulator of HO-1 induction. Through the antioxidant, antiapoptotic, and antinflammatory properties of its metabolic products, HO-1 plays a key role in healthy cells in maintaining redox homeostasis and in preventing carcinogenesis. Nevertheless, several lines of evidence have highlighted the role of HO-1 in cancer progression and its expression correlates with tumor growth, aggressiveness, metastatic and angiogenetic potential, resistance to therapy, tumor escape, and poor prognosis, even though a tumor- and tissue-specific activity has been observed. In this review, we summarize the current literature regarding the pro-tumorigenic role of HO-1 dependent tumor progression as a promising target in anticancer strategy.

WBP2 modulates G1/S transition in ER+ breast cancer cells and is a direct target of miR-206

PURPOSE

The mechanisms underlying the oncogenic properties of WW domain binding protein 2 (WBP2) in breast cancer have not been fully understood. In this study, we explored the role of WBP2 in cell cycle regulation in ER+ breast cancer cells and how it is regulated in the cancer cells.

METHODS

The association between WBP2 expression and prognosis in ER+ breast cancer was assessed by data mining in Breast Cancer Gene-Expression Miner v4.0. Cell cycle was assessed by PI staining and flow cytometry. EdU staining was applied to visualize cells in S phase. The binding between miR-206 and WBP2 were verified by dual luciferase assay. CCK-8 assay and flow cytometric analysis were applied to assess the functional role of WBP2 and miR-206 in the cancer cells.

RESULTS

High WBP2 expression correlates with higher risk of any events (AE) and metastatic relapse (MR) and also indicates shorter AE-free survival and MR-free survival in ER+ breast cancer patients. In both MCF-7 and BT474 cells, WBP can influence the expression of G1/S-related cell cycle proteins, including p21, CDK4, and cyclin D1. In addition, WBP2 overexpression resulted in facilitated G1/S transition, while WBP2 knockdown impaired the transition. The 3'UTR of WBP2 has a conserved miR-206 binding site. Functionally, miR-206 knockdown decreased tamoxifen sensitivity in tamoxifen-sensitive (TamS) MCF-7 cells, while miR-206 overexpression and WBP2 knockdown enhanced the sensitivity in tamoxifen-resistant (TamR) MCF-7 cells.

CONCLUSION

Based on these findings, we infer that the miR-206/WBP2 axis can modulate tamoxifen sensitivity via regulating G1/S progression in ER+ breast cancer.

SNIPER(TACC3) induces cytoplasmic vacuolization and sensitizes cancer cells to Bortezomib

We previously developed a hybrid small molecule SNIPER (Specific and Nongenetic IAP‐dependent Protein ERaser) against transforming acidic coiled‐coil‐3 (TACC3), SNIPER(TACC3), that induces proteasomal degradation of TACC3 protein. In this study, we found that SNIPER(TACC3) induces cytoplasmic vacuolization derived from endoplasmic reticulum (ER) and paraptosis‐like cell death selectively in cancer cells. Mechanistic analysis suggests that accumulation of ubiquitylated protein aggregates that requires X‐linked inhibitor of apoptosis protein (XIAP) induces ER stress, which results in ER‐stress responses involving X‐box binding protein‐1 (XBP‐1) and ER‐derived vacuolization in cancer cells. Importantly, inhibition of proteasome enhanced the SNIPER(TACC3)‐induced vacuolization, and the combination treatment of SNIPER(TACC3) and bortezomib exhibited a synergistic anticancer activity in several cancer cell lines. The induction of paraptosis‐like cell death in cancer cells by SNIPER(TACC3) could be applied to treat cancer cells resistant to undergo apoptosis by overexpression of XIAP.

Cytotoxicity of Pyrazine-Based Cyclometalated (C^Npz^C)Au(III) Carbene Complexes: Impact of the Nature of the Ancillary Ligand on the Biological Properties

The synthesis of a series of cyclometalated gold(III) complexes supported by pyrazine-based (C^N^C)-type pincer ligands is reported, including the crystal structure of a cationic example. The compounds provide a new platform for the study of antiproliferative properties of gold(III) complexes. Seven complexes were tested: the neutral series (C^N^pz^C)AuX [X = Cl (1), 6-thioguanine (4), C≡CPh (5), SPh (6)] and an ionic series that included the N-methyl complex [(C^N^pzMe^C)AuCl]BF₄ (7) and the N-heterocyclic carbene complexes [(C^N^pz^C)AuL]⁺ with L = 1,3-dimethylbenzimidazol-2-ylidene (2) or 1,3,7,9-tetramethylxanthin-8-ylidene (3). Tests against human leukemia cells identified 1, 2, 3, and 4 as particularly promising, whereas protecting the noncoordinated N atom on the pyrazine ring by methylation (as in 7) reduced the cytotoxicity. Complex 2 proved to be the most effective of the entire series against the HL60 leukemia, MCF-7 breast cancer, and A549 lung cancer cell lines, with IC₅₀ values down to submicromolar levels, associated with a lower toxicity toward healthy human lung fibroblast cells. The benzimidazolylidene complex 2 accumulated more effectively in human lung cancer cells than its caffeine-based analogue 3 and the gold(III) chloride 1. Compound 2 proved to be unaffected by glutathione under physiological conditions for periods of up to 6 days and stabilizes the DNA G-quadruplex and i-motif structures; the latter is the first such report for gold compounds. We also show the first evidence of inhibition of MDM2–p53 protein–protein interactions by a gold-based compound and identified the binding mode of the compound with MDM2 using saturation transfer difference NMR spectroscopy combined with docking calculations.

We synthesized three new (C^N^pz^C)Au(III) complexes and screened them along with four other complexes as potential anticancer agents against leukemia cells. We tested the cellular uptake, the interaction with G4 and i-motif DNA structures, and the interaction with MDM2 protein. We highlight the very different biological behaviors of the compounds due to the different ancillary ligands.

DNA damage by lipid peroxidation products: implications in cancer, inflammation and autoimmunity

Oxidative stress and lipid peroxidation (LPO) induced by inflammation, excess metal storage and excess caloric intake cause generalized DNA damage, producing genotoxic and mutagenic effects. The consequent deregulation of cell homeostasis is implicated in the pathogenesis of a number of malignancies and degenerative diseases. Reactive aldehydes produced by LPO, such as malondialdehyde, acrolein, crotonaldehyde and 4-hydroxy-2-nonenal, react with DNA bases, generating promutagenic exocyclic DNA adducts, which likely contribute to the mutagenic and carcinogenic effects associated with oxidative stress-induced LPO. However, reactive aldehydes, when added to tumor cells, can exert an anticancerous effect. They act, analogously to other chemotherapeutic drugs, by forming DNA adducts and, in this way, they drive the tumor cells toward apoptosis. The aldehyde-DNA adducts, which can be observed during inflammation, play an important role by inducing epigenetic changes which, in turn, can modulate the inflammatory process. The pathogenic role of the adducts formed by the products of LPO with biological macromolecules in the breaking of immunological tolerance to self antigens and in the development of autoimmunity has been supported by a wealth of evidence. The instrumental role of the adducts of reactive LPO products with self protein antigens in the sensitization of autoreactive cells to the respective unmodified proteins and in the intermolecular spreading of the autoimmune responses to aldehyde-modified and native DNA is well documented. In contrast, further investigation is required in order to establish whether the formation of adducts of LPO products with DNA might incite substantial immune responsivity and might be instrumental for the spreading of the immunological responses from aldehyde-modified DNA to native DNA and similarly modified, unmodified and/or structurally analogous self protein antigens, thus leading to autoimmunity.

Effect of a corticosteroid (triamcinolone) and chlorhexidine on chemotherapy-induced oxidative stress in the buccal mucosa of rats

Oral mucositis manifests as erythematous and ulcerative lesions of the oral mucosa. Among its various causes, cancer treatment (e.g., chemotherapy with or without radiation therapy) is one of the more well known. It has been widely mentioned that oxidative stress parameters such as lipid peroxidation levels increase during the cancer process. Glutathione is one of the major intracellular enzymes used to detoxify oxidant molecules; it exists in both a reduced and oxidized state. Reduced glutathione is used as a substrate to synthesize glutathione peroxidase. We conducted a study to investigate and compare the effects of triamcinolone (a synthetic steroid) and chlorhexidine (a chemical antiseptic) on 5-fluorouracil (5-FU; a chemotherapeutic agent)-induced oral mucositis in the buccal mucosa of 36 rats. Oral mucositis was induced through a combination of 5-FU treatment and mild abrasion of the cheek pouch with a wire brush. The rats were treated with one of four regimens: saline placebo (group I), 5-FU only (group II), 5-FU plus triamcinolone (group III), and 5-FU plus chlorhexidine (group IV). Three rats in the triamcinolone group died of unknown causes on days 7 and 8, and 3 rats in the chlorhexidine group died on days 7 and 9. On day 9, the remaining 30 rats were sacrificed and examined. Buccal mucosa lipid peroxidation levels were significantly higher in the 5-FU-only group than in the control group and significantly higher in the control group than in the triamcinolone group (p < 0.05 for both). Levels of reduced glutathione were significantly lower in the 5-FU-only group than in both the triamcinolone group and the chlorhexidine group (p < 0.05). Glutathione peroxidase activity was significantly higher in the triamcinolone group than in the 5-FU-only group (p < 0.01). Histopathologic analysis revealed that treatment with triamcinolone significantly reduced 5-FU-induced inflammatory cell infiltration and ulceration (p < 0.001); no such reduction was seen with chlorhexidine. In conclusion, we observed that triamcinolone and chlorhexidine treatment modulated chemotherapy-induced oxidative injury in rat oral mucositis. However, only triamcinolone histopathologically ameliorated 5-FU-induced oral mucositis. These findings suggest that triamcinolone is a useful agent for the management of experimental oxidative injury and oral mucositis caused by 5-FU chemotherapy.

Synthetic β-nitrostyrene derivative CYT-Rx20 as inhibitor of oral cancer cell proliferation and tumor growth through glutathione suppression and reactive oxygen species induction

BACKGROUND

The β-nitrostyrene family possesses anticancer properties. In this study, β-nitrostyrene derivative CYT-Rx20 (3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene) was synthesized and investigated its anticancer activity in oral cancer.

METHODS

Anticancer activity of CYT-Rx20 and the underlying mechanisms were analyzed using cell viability assay, reactive oxygen species (ROS) generation assay, fluorescence-activated cell sorter analysis, annexin V staining, comet assay, glutathione (GSH)/glutathione disulfide (GSSG) ratio, immunoblotting, soft agar assay, nude mice xenograft study, and immunohistochemistry.

RESULTS

CYT-Rx20-induced cell apoptosis via ROS generation and mitochondrial membrane potential reduction, associated with release of mitochondrial cytochrome C to cytosol and activation of downstream caspases and poly ADP-ribose polymerase (PARP). Furthermore, CYT-Rx20 induced mitochondrial ROS accumulation and mitochondrial dysfunction, followed by GSH downregulation. CYT-Rx20-induced cell apoptosis, ROS generation, and DNA damage were reversed by thiol antioxidants. In nude mice, CYT-Rx20 inhibited oral tumor growth accompanied by increased expression of γH2AX, GSH reductase, and cleaved-caspase-3.

CONCLUSION

CYT-Rx20 has the potential to be further developed into an antioral cancer drug clinically. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1055-1064, 2017.

Chemotherapy Resistance Mechanisms in Advanced Skin Cancer

Melanoma is a most dangerous and deadly type of skin cancer, and considered intrinsically resistant to both radiotherapy and chemotherapy. It has become a major public health concern as the incidence of melanoma has been rising steadily over recent decades with a 5-year survival remaining less than 5%. Detection of the disease in early stage may be curable, but late stage metastatic disease that has spread to other organs has an extremely poor prognosis with a median survival of less than 10 months. Since metastatic melanoma is unresponsive to therapy that is currently available, research is now focused on different treatment strategies such as combinations of surgery, chemotherapy and radiotherapy. The molecular basis of resistance to chemotherapy seen in melanoma is multifactorial; defective drug transport system, altered apoptotic pathway, deregulation of apoptosis and/or changes in enzymatic systems that mediate cellular metabolic machinery. Understanding of alterations in molecular processes involved in drug resistance may help in developing new therapeutic approaches to treatment of malignant melanoma.

Methylene blue photodynamic therapy induces selective and massive cell death in human breast cancer cells

BACKGROUND

Breast cancer is the main cause of mortality among women. The disease presents high recurrence mainly due to incomplete efficacy of primary treatment in killing all cancer cells. Photodynamic therapy (PDT), an approach that causes tissue destruction by visible light in the presence of a photosensitizer (Ps) and oxygen, appears as a promising alternative therapy that could be used adjunct to chemotherapy and surgery for curing cancer. However, the efficacy of PDT to treat breast tumours as well as the molecular mechanisms that lead to cell death remain unclear.

METHODS

In this study, we assessed the cell-killing potential of PDT using methylene blue (MB-PDT) in three breast epithelial cell lines that represent non-malignant conditions and different molecular subtypes of breast tumours. Cells were incubated in the absence or presence of MB and irradiated or not at 640 nm with 4.5 J/cm2. We used a combination of imaging and biochemistry approaches to assess the involvement of classical autophagic and apoptotic pathways in mediating the cell-deletion induced by MB-PDT. The role of these pathways was investigated using specific inhibitors, activators and gene silencing.

RESULTS

We observed that MB-PDT differentially induces massive cell death of tumour cells. Non-malignant cells were significantly more resistant to the therapy compared to malignant cells. Morphological and biochemical analysis of dying cells pointed to alternative mechanisms rather than classical apoptosis. MB-PDT-induced autophagy modulated cell viability depending on the cell model used. However, impairment of one of these pathways did not prevent the fatal destination of MB-PDT treated cells. Additionally, when using a physiological 3D culture model that recapitulates relevant features of normal and tumorous breast tissue morphology, we found that MB-PDT differential action in killing tumour cells was even higher than what was detected in 2D cultures.

CONCLUSIONS

Finally, our observations underscore the potential of MB-PDT as a highly efficient strategy which could use as a powerful adjunct therapy to surgery of breast tumours, and possibly other types of tumours, to safely increase the eradication rate of microscopic residual disease and thus minimizing the chance of both local and metastatic recurrence.

Histone Methyltransferase G9a Drives Chemotherapy Resistance by Regulating the Glutamate-Cysteine Ligase Catalytic Subunit in Head and Neck Squamous Cell Carcinoma

Transient chemotherapeutic response is a major obstacle to treating head and neck squamous cell carcinomas (HNSCC). Histone methyltransferase G9a has recently been shown to be abundantly expressed in HNSCC, and is required to maintain the malignant phenotype. In this study, we found that high G9a expression is significantly associated with poor chemotherapeutic response and disease-free survival in HNSCC patients. Similarly, G9a expression and enzymatic activity were elevated in cisplatin-resistant HNSCC cells. Genetic or pharmacologic inhibition of G9a sensitized the resistant cells to cisplatin, increasing cellular apoptosis. Mechanistic investigations indicated that G9a contributes to transcriptional activation of the glutamate-cysteine ligase catalytic subunit (GCLC), which results in upregulation of cellular glutathione (GSH) and drug resistance. In addition, we observed a significant positive correlation between G9a and GCLC expression in tumors of HNSCC patients. Taken together, our findings provide evidence that G9a protects HNSCC cells against chemotherapy by increasing the synthesis of GSH, and imply G9a as a promising target for overcoming cisplatin resistance in HNSCC. Mol Cancer Ther; 16(7); 1421-34. ©2017 AACR.

Dehydrobruceine B enhances the cisplatin-induced cytotoxicity through regulation of the mitochondrial apoptotic pathway in lung cancer A549 cells

Dehydrobruceine B (DHB) is a quassinoid isolated from Brucea javanica. We have shown previously that DHB induced apoptosis on two kinds of lung cancer cell lines, A549 and NCI-H292. In the present study, we investigated the interactions of DHB and cisplatin (CDDP) on apoptotic-related cancer cell death. Synergistic effects on cell proliferation and apoptosis were observed when A549 cells were treated with DHB plus CDDP. DHB combined CDDP exposure increased depolarization of mitochondrial membrane potential (MMP) and release of cytochrome c from mitochondria into the cytoplasm. The combination treatment also enhanced protein expression of Bax, reduced the protein levels of Bcl-xL and Bcl-2, and increased the cleavage of caspase-3, caspase-9 and poly (ADP-ribose) polymerase (PARP). These results indicated that DHB sensitized A549 cells to cisplatin by regulating the mitochondrial apoptotic pathway. High constitutive expression of Nrf2 was found in A549 cells, which enhance the resistance of cancer cells to chemotherapeutic agents including cisplatin. DHB reduced the protein levels of Nrf2 and its target genes, which may contribute to the increase of intracellular ROS level, consequently, induced mitochondria apoptosis. These results generated a rationale for further investigation of DHB combined with CDDP as a potential therapeutic strategy in lung cancer.

Role of uL3 in Multidrug Resistance in p53-Mutated Lung Cancer Cells

Cancer is one of the most common causes of death among adults. Chemotherapy is crucial in determining patient survival and quality of life. However, the development of multidrug resistance (MDR) continues to pose a significant challenge in the management of cancer. In this study, we analyzed the role of human ribosomal protein uL3 (formerly rpL3) in multidrug resistance. Our studies revealed that uL3 is a key determinant of multidrug resistance in p53-mutated lung cancer cells by controlling the cell redox status. We established and characterized a multidrug resistant Calu-6 cell line. We found that uL3 down-regulation correlates positively with multidrug resistance. Restoration of the uL3 protein level re-sensitized the resistant cells to the drug by regulating the reactive oxygen species (ROS) levels, glutathione content, glutamate release, and cystine uptake. Chromatin immunoprecipitation experiments and luciferase assays demonstrated that uL3 coordinated the expression of stress-response genes acting as transcriptional repressors of solute carrier family 7 member 11 (xCT) and glutathione S-transferase α1 (GST-α1), independently of Nuclear factor erythroid 2-related factor 2 (Nrf2). Altogether our results describe a new function of uL3 as a regulator of oxidative stress response genes and advance our understanding of the molecular mechanisms underlying multidrug resistance in cancers.

Aspirin plus sorafenib potentiates cisplatin cytotoxicity in resistant head and neck cancer cells through xCT inhibition

The nonsteroidal anti-inflammatory drug aspirin and the multikinase inhibitor sorafenib have both shown experimental and clinical anticancer activities. The present study investigated whether aspirin and sorafenib synergize to potentiate cisplatin treatment in resistant head and neck cancer (HNC) cells. The effects of aspirin, sorafenib and cisplatin, and combinations thereof were assessed by measuring cell viability, death, glutathione (GSH) and reactive oxygen species (ROS) levels, protein and mRNA expression, genetic inhibition and overexpression of cystine-glutamate antiporter (xCT) and tumor xenograft mouse models. Even at low concentrations, aspirin plus sorafenib synergized to induce cell death of cisplatin-resistant HNC cells. The combination of aspirin and sorafenib induced xCT inhibition, GSH depletion, and ROS accumulation in cancer cells. Genetic and pharmacological inhibition of xCT potentiated the cytotoxic effects of aspirin plus sorafenib; this effect was diminished by xCT overexpression. Low-dose aspirin plus sorafenib enhanced the cytotoxicity of cisplatin in resistant HNC cells through xCT inhibition and oxidant and DNA damage. The in vivo effects of aspirin plus sorafenib on cisplatin therapy were also confirmed in resistant HNC xenograft models, in terms of growth inhibition, GSH depletion, and increased γH2AX formation and apoptosis in tumors. Aspirin and sorafenib synergize to potentiate the cytotoxicity of cisplatin in resistant HNC cells. This therapeutic strategy may help to eliminate resistant HNC.

Activatable probes for diagnosis and biomarker detection by MRI

Magnetic resonance imaging (MRI) is a non-invasive imaging technique with widespread use in diagnosis. Frequently, contrast in MRI is enhanced with the aid of a contrast agent, among which smart, responsive, OFF/ON or activatable probes are of particular interest. These kinds of probes elicit a response to selective stimuli, evidencing the presence of enzymes or acidic pH, for instance. In this review, we will focus on smart probes that are detectable by both ¹H and ¹⁹F MRI, frequently based on nanomaterials. We will discuss the triggering factors and the strategies employed thus far to activate each probe.

The method for breast cancer grade prediction and pathway analysis based on improved multiple kernel learning

Breast cancer histologic grade represents the morphological assessment of the tumor’s malignancy and aggressiveness, which is vital in clinically planning treatment and estimating prognosis for patients. Therefore, the prediction of breast cancer grade can markedly elevate the detection of early breast cancer and efficiently guide its treatment. With the advent of high-throughput profiling technology, a large number of data of different types are rapidly generated, and each data provides its unique biological insight. Although many researches focused on cancer grade prediction, hardly most of them attempted to integrate multiple data types, by which we cannot only improve and boost results obtained from learning method, but also have a good understanding or explanation of biological issues. In this paper, we take advantage of a sophisticated supervised learning method called multiple kernel learning (MKL) to design a breast cancer grading predictor fusing heterogeneous data for classification of breast cancer histopathology. Furthermore, we modify our model by involving biological pathway information. The new model can evaluate the significance of various pathways in which differential expression genes fall between different breast cancer grades. The merits of the novel model are lucubration in bridging between omics data and various phenotypes of breast cancer grades, and providing an auxiliary method integrating omics data of cancer mechanism research. In experiments, the proposed method outperforms other state-of-the-art methods and has abundant biological interpretation in explaining differences between breast cancer grades.

Updates of the role of oxidative stress in the pathogenesis of ovarian cancer

Clinical and epidemiological investigations have provided evidence supporting the role of reactive oxygen species (ROS) and reactive nitrogen species (RNS), collectively known as oxidative stress, in the etiology of cancer. Exogenous factors such as chronic inflammation, infection and hypoxia are major sources of cellular oxidative stress. Specifically, oxidative stress plays an important role in the pathogenesis, neoangiogenesis, and dissemination of local or distant ovarian cancer, as it is known to induce phenotypic modifications of tumor cells by cross talk between tumor cells and the surrounding stroma. Subsequently, the biological significance of the relationship between oxidative stress markers and various stages of epithelial ovarian cancer highlights potential therapeutic interventions as well as provides urgently needed early detection biomarkers. In the light of our scientific research and the most recent experimental and clinical observations, this review provides the reader with up to date most relevant findings on the role of oxidative stress in the pathogenesis of ovarian cancer and the possible therapeutic implications.

SLC25A26 overexpression impairs cell function via mtDNA hypermethylation and rewiring of methyl metabolism

Cancer cells down-regulate different genes to give them a selective advantage in invasiveness and/or metastasis. The SLC25A26 gene encodes the mitochondrial carrier that catalyzes the import of S-adenosylmethionine (SAM) into the mitochondrial matrix, required for mitochondrial methylation processes, and is down-regulated in cervical cancer cells. In this study we show that SLC25A26 is down-regulated due to gene promoter hypermethylation, as a mechanism to promote cell survival and proliferation. Furthermore, overexpression of SLC25A26 in CaSki cells increases mitochondrial SAM availability and promotes hypermethylation of mitochondrial DNA, leading to decreased expression of key respiratory complex subunits, reduction of mitochondrial ATP and release of cytochrome c. In addition, increased SAM transport into mitochondria leads to impairment of the methionine cycle with accumulation of homocysteine at the expense of glutathione, which is strongly reduced. All these events concur to arrest the cell cycle in the S phase, induce apoptosis and enhance chemosensitivity of SAM carrier-overexpressing CaSki cells to cisplatin.

Clinically Evaluated Cancer Drugs Inhibiting Redox Signaling

SIGNIFICANCE

There are a number of redox-active anticancer agents currently in development based on the premise that altered redox homeostasis is necessary for cancer cell's survival. Recent Advances: This review focuses on the relatively few agents that target cellular redox homeostasis to have entered clinical trial as anticancer drugs.

CRITICAL ISSUES

The success rate of redox anticancer drugs has been disappointing compared to other classes of anticancer agents. This is due, in part, to our incomplete understanding of the functions of the redox targets in normal and cancer tissues, leading to off-target toxicities and low therapeutic indexes of the drugs. The field also lags behind in the use biomarkers and other means to select patients who are most likely to respond to redox-targeted therapy.

FUTURE DIRECTIONS

If we wish to derive clinical benefit from agents that attack redox targets, then the future will require a more sophisticated understanding of the role of redox targets in cancer and the increased application of personalized medicine principles for their use. Antioxid. Redox Signal. 26, 262-273.

Study of early stage non-small-cell lung cancer using Orbitrap-based global serum metabolomics

Purpose

The aim of the project was to apply ultra-high-performance liquid chromatography–quadrupole-Orbitrap-high-resolution mass spectrometry for serum metabolite profiling of non-small-cell lung cancer (NSCLC). This Orbitrap-based methodology has been applied for a study of NSCLC potential markers for the first time.

Methods

After extraction using protein precipitation, sera were separated on the ACE Excel 2 C18-PFP (100 × 2.1 mm, 2.0 µm) column using gradient elution and analyzed within the range of 70–1000 m/z. Only patients with early stage disease (stages IA–IIB) were included in the study, providing opportunity to find biomarkers for early lung cancer detection. The resulting metabolite profiles were subjected to univariate and multivariate statistical tests.

Results

36 features were found significantly changed between NSCLC group and controls after FDR adjustment and 19 were identified using various metabolite databases (in-house library, HMDB, mzCloud). The study revealed a number of NSCLC biomarker candidates which belong to such compound classes as acylcarnitines, organic acids, and amino acids. Multivariate ROC curve built using 12 identified metabolites was characterized by AUC = 0.836 (0.722–0.946). There were no significant differences in the serum metabolite profiles between two most common histological types of lung cancer—adenocarcinoma and squamous cell carcinoma.

Conclusions

Through identification of novel potential tumor markers, Orbitrap-based global metabolic profiling is a useful strategy in cancer research. Our study can accelerate development of new diagnostic and therapeutic strategies in NSCLC. The metabolites involved in discrimination between NSCLC patients and the control subjects should be further explored using a targeted approach.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-017-2347-0) contains supplementary material, which is available to authorized users.

Epithelial response to a high-protein diet in rat colon

Background

High-protein diets (HPD) alter the large intestine microbiota composition in association with a metabolic shift towards protein degradation. Some amino acid-derived metabolites produced by the colon bacteria are beneficial for the mucosa while others are deleterious at high concentrations. The aim of the present work was to define the colonic epithelial response to an HPD. Transcriptome profiling was performed on colonocytes of rats fed an HPD or an isocaloric normal-protein diet (NPD) for 2 weeks.

Results

The HPD downregulated the expression of genes notably implicated in pathways related to cellular metabolism, NF-κB signaling, DNA repair, glutathione metabolism and cellular adhesion in colonocytes. In contrast, the HPD upregulated the expression of genes related to cell proliferation and chemical barrier function. These changes at the mRNA level in colonocytes were not associated with detrimental effects of the HPD on DNA integrity (comet assay), epithelium renewal (quantification of proliferation and apoptosis markers by immunohistochemistry and western blot) and colonic barrier integrity (Ussing chamber experiments).

Conclusion

The modifications of the luminal environment after an HPD were associated with maintenance of the colonic homeostasis that might be the result of adaptive processes in the epithelium related to the observed transcriptional regulations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3514-z) contains supplementary material, which is available to authorized users.

Polymeric Biomaterials: Diverse Functions Enabled by Advances in Macromolecular Chemistry

Biomaterials have been extensively used to leverage beneficial outcomes in various therapeutic applications, such as providing spatial and temporal control over the release of therapeutic agents in drug delivery as well as engineering functional tissues and promoting the healing process in tissue engineering and regenerative medicine. This perspective presents important milestones in the development of polymeric biomaterials with defined structures and properties. Contemporary studies of biomaterial design have been reviewed with focus on constructing materials with controlled structure, dynamic functionality, and biological complexity. Examples of these polymeric biomaterials enabled by advanced synthetic methodologies, dynamic chemistry/assembly strategies, and modulated cell-material interactions have been highlighted. As the field of polymeric biomaterials continues to evolve with increased sophistication, current challenges and future directions for the design and translation of these materials are also summarized.

Loss of Merlin induces metabolomic adaptation that engages dependence on Hedgehog signaling

The tumor suppressor protein Merlin is proteasomally degraded in breast cancer. We undertook an untargeted metabolomics approach to discern the global metabolomics profile impacted by Merlin in breast cancer cells. We discerned specific changes in glutathione metabolites that uncovered novel facets of Merlin in impacting the cancer cell metabolome. Concordantly, Merlin loss increased oxidative stress causing aberrant activation of Hedgehog signaling. Abrogation of GLI-mediated transcription activity compromised the aggressive phenotype of Merlin-deficient cells indicating a clear dependence of cells on Hedgehog signaling. In breast tumor tissues, GLI1 expression enhanced tissue identification and discriminatory power of Merlin, cumulatively presenting a powerful substantiation of the relationship between these two proteins. We have uncovered, for the first time, details of the tumor cell metabolomic portrait modulated by Merlin, leading to activation of Hedgehog signaling. Importantly, inhibition of Hedgehog signaling offers an avenue to target the vulnerability of tumor cells with loss of Merlin.

[Targeted imaging ability of a biotinylated imaging probe Biotin-S-S-Rhodol for breast cancer cells in vitro]

OBJECTIVE

To investigate performance of a biotinylated imaging probe 3a for targeted imaging of breast cancer cells.

METHODS

Ultraviolet absorption spectrum and fluorescence spectrum were employed to analyze the spectral characteristics of 3a. The fluorescence spectrums of 3a treated with different concentrations of glutathione (GSH) were obtained to determine the sensibility of 3a to GSH. Flow cytometry was used to determine the cellular uptake of 3a by MCF-7 cells, MDA-MB-231 cells and Hs 578Bst cells in the presence or absence of biotin, and the imaging performance of 3a in the 3 cell lines was assessed under an inverted fluorescent microscope. The toxicity of 3a to the cells was evaluated using MTT method.

RESULTS

3a showed the strongest absorption peak at 510 nm, and its fluorescence emission signal was the strongest at 544 nm. As the concentration of GSH increased (0-6 mmol/L), 3a exhibited an increasing fluorescence signal at 544 nm. The cellular uptake of 3a was markedly higher in MDA-MB-231 cells and MCF-7 cells than in Hs 578Bst cells. The imaging studies showed that 3a had a good breast cancer cell-targeting property and produced clear images under fluorescent microscope. MTT assay demonstrated no obvious toxicity of 3a in Hs 578Bst cells even at the concentration of 20 µmol/L, but MCF-7 cells and MDA-MB-231 cells exposed to 2-20 µmol/L 3a showed a lowered cell viability.

CONCLUSION

3a is capable of targeted imaging of breast cancer cells mediated by biotin. 3a at the concentration of 2-20 µmol/L has minimal cytotoxicity to normal breast cells but can lower the viability of breast cancer cells.

Changes of Oxidative Stress, Glutathione, and Its Dependent Antioxidant Enzyme Activities in Patients with Hepatocellular Carcinoma before and after Tumor Resection

The changes in and relationship between oxidative stress and the glutathione (GSH) antioxidant system in the plasma and tissues of patients with hepatocellular carcinoma (HCC) before and after tumor resection have not been clearly determined. We investigated the changes in oxidative stress, GSH status and its dependent antioxidant enzyme activities in HCC patients before and after tumor resection, and to determine the association of oxidative stress with GSH and its dependent antioxidant enzyme activities in plasma and tissues. This study employed a cross-sectional design. Forty-four men and 16 women with HCC were recruited. Fasting blood was drawn on the day before the tumor resection and one month after the tumor resection. HCC tissue and adjacent normal liver tissue were obtained at the time of surgical resection. Patients had significantly increased plasma malondialdehyde (MDA) and oxidized-low density lipoprotein levels but decreased GSH and oxidized GSH levels before tumor resection compared with the corresponding post-resection values. GSH and trolox equivalent antioxidant capacity (TEAC) levels and activities of GSH peroxidase were significantly increased while MDA level was significantly lower in HCC tissue when compared with the adjacent normal tissue. The pre-resection plasma MDA level was significantly correlated with pre-resection plasma GSH concentration, and MDA level in HCC and adjacent normal tissues. Pre-resection plasma GSH concentration was significantly correlated with GSH and TEAC level in HCC tissue. HCC patients had increased oxidative stress, decreased GSH, and lower dependent antioxidant capacities before tumor resection. However, hepatocellular tumor had increased GSH and TEAC levels as well as GSH peroxidase activities which might protect itself against increased oxidative stress.

Insights into Biochemical Alteration in Cancer-Associated Fibroblasts by using Novel Correlative Spectroscopy

The microenvironment of a tumor changes chemically and morphologically during cancer progression. Cancer‐stimulated fibroblasts promote tumor growth, however, the mechanism of the transition to a cancer‐stimulated fibroblast remains elusive. Here, the multi‐modal spectroscopic methods Fourier transform infrared imaging (FTIRI), X‐ray absorption spectroscopy (XAS) and X‐ray fluorescence imaging (XFI) are used to characterize molecular and atomic alterations that occur in cancer‐stimulated fibroblasts. In addition to chemical changes in lipids (olefinic and acyl chain) and protein aggregation observed with FTIRI, a new infrared biomarker for oxidative stress in stimulated fibroblasts is reported. Oxidative stress is observed to cause lipid peroxidation, which leads to the appearance of a new band at 1721 cm⁻¹, assigned to 4‐hydroxynonenal. Complementary to FTIRI, XFI is well suited to determining atom concentrations and XAS can reveal the speciation of individual elements. XFI reveals increased concentrations of P, S, K, Ca within stimulated fibroblasts. Furthermore, XAS studies reveal alterations in the speciation of S and Ca in stimulated fibroblasts, which might provide insight into the mechanisms of cancer progression. Using XFI, not only is the concentration change of individual elements observed, but also the subcellular localization. This study demonstrates the wealth of biochemical information provided by a multi‐modal imaging approach and highlights new avenues for future research into the microenvironment of breast tumors.

MiR-148a and miR-152 reduce tamoxifen resistance in ER+ breast cancer via downregulating ALCAM

Activated leukocyte cell adhesion molecule (ALCAM), also called CD166 is a 105-kDa transmembrane glycoprotein of the immunoglobin superfamily. In this study, we studied the association between ALCAM expression and tamoxifen resistance in ER + breast cancer and further investigated how ALCAM is regulated in the cancer cells. IHC staining data showed that the tumor tissues from non-responders (N = 20) generally had significantly stronger ALCAM staining than that from tamoxifen responders (N = 16). In vitro cell assay also confirmed ALCAM upregulation in tamoxifen resistant (TamR) MCF-7 cells than in tamoxifen sensitive (TamS) MCF-7 cells. ALCAM overexpression significantly alleviated 4-Hydroxytestosterone (4-OHT) induced cell viability inhibition and cell apoptosis in TamS MCF-7 cells, while ALCAM knockdown remarkably enhanced 4-OHT induced cell viability inhibition and cell apoptosis in TamR MCF-7 cells. Demethylation reagent treatment significantly restored miR-148a and miR-152 expression in TamR MCF-7 cells. MiR-148a and miR-152 can directly target ALCAM 3'UTR and decrease ALCAM expression. MiR-148a overexpression had similar effect as ALCAM siRNA on enhancing 4-OHT induced cell viability inhibition and cell apoptosis in TamR MCF-7 cells. MiR-152 overexpression alone caused growth inhibition and increased cell apoptosis in TamR MCF-7 cells. It also enhanced the effect of 4-OHT. Simultaneous inhibition of miR-148a and miR-152 significantly protected TamS MCF-7 cells from 4-OHT induced cell viability inhibition and cell apoptosis. Based on these findings, we infer that MiR-148a and miR-152 can sensitize TamR MCF-7 cells to tamoxifen at least via downregulating ALCAM.

LC-MS-based metabolomics reveals metabolic signatures related to glioma stem-like cell self-renewal and differentiation

A metabolomic study of three glioma cell lines with different stemness were conducted. The specific metabolite signatures associated with SLC self-renewal and differentiation were characterized.

Cytotoxic activity of soy phytoestrogen coumestrol against human breast cancer MCF-7 cells: Insights into the molecular mechanism

Coumestrol is a phytoestrogen present in soybean products and recognized as potential cancer therapeutic agent against breast cancer. However, the clear molecular mechanism of anticancer-activity of coumestrol in breast carcinoma has not been reported. It is well established that copper levels are elevated in different malignancies. Therefore, the objective of this study was to investigate the copper-dependent cytotoxic action of coumestrol in human breast cancer MCF-7 cells. Results showed that coumestrol inhibited proliferation and induced apoptosis in MCF-7 cells, which was prevented by copper chelator neocuproine and ROS scavengers. Coumestrol treatment induced ROS generation coupled to DNA fragmentation, up-regulation of p53/p21, cell cycle arrest at G1/S phase, mitochondrial membrane depolarization and caspases 9/3 activation. All these effects were suppressed by ROS scavengers and neocuproine. These results suggest that coumestrol targets elevated copper for redox cycling to generate ROS leading to DNA fragmentation. DNA damage leads to p53 up-regulation which directs the cell cycle arrest at G1/S phase and promotes caspase-dependent apoptosis of MCF-7 cells. In conclusion, copper targeted ROS-mediated p53-dependent mechanism better explains the cytotoxic action of coumestrol in MCF-7 cells. Thus, targeting elevated copper levels might be a potential therapeutic strategy for selective cytotoxic action against malignant cells.

Glutathione-responsive nanoparticles based on a sodium alginate derivative for selective release of doxorubicin in tumor cells

GSH-responsive nanoparticles based on disulfide crosslinked amphiphilic alginate demonstrated selected drug release in cancer cells with a much improved safety profile.

Regulation of multidrug resistance by microRNAs in anti-cancer therapy

Multidrug resistance (MDR) remains a major clinical obstacle to successful cancer treatment. Although diverse mechanisms of MDR have been well elucidated, such as dysregulation of drugs transporters, defects of apoptosis and autophagy machinery, alterations of drug metabolism and drug targets, disrupti on of redox homeostasis, the exact mechanisms of MDR in a specific cancer patient and the cross-talk among these different mechanisms and how they are regulated are poorly understood. MicroRNAs (miRNAs) are a new class of small noncoding RNAs that could control the global activity of the cell by post-transcriptionally regulating a large variety of target genes and proteins expression. Accumulating evidence shows that miRNAs play a key regulatory role in MDR through modulating various drug resistant mechanisms mentioned above, thereby holding much promise for developing novel and more effective individualized therapies for cancer treatment. This review summarizes the various MDR mechanisms and mainly focuses on the role of miRNAs in regulating MDR in cancer treatment.

Targeted combinational therapy inducing mitochondrial dysfunction

Mitochondria-directed GSH-activated release of a chlorambucil derivative and an AIE dye induces significantly increased mitochondrial dysfunction and apoptosis.

P53 mutations and cancer: a tight linkage

P53 is often mutated in solid tumors, in fact, somatic changes involving the gene encoding for p53 (TP53) have been discovered in more than 50% of human malignancies and several data confirmed that p53 mutations represent an early event in cancerogenesis. Main p53 functions consist in cell cycle arrest, DNA repair, senescence and apoptosis induction in response to mutagenic stimuli, and, to exert those functions, p53 acts as transcriptional factor. Recent data have highlighted another very important role of p53, consisting in regulate cell metabolism and cell response to oxidative stress. Majority of tumor suppressor genes, such as adenomatous polyposis coli (APC), retinoblastoma-associated protein (RB) and Von-Hippel-Lindau (VHL) are inactivated by deletion or early truncation mutations in tumors, resulting in the decreased or loss of expression of their proteins. Differently, most p53 mutations in human cancer are missense mutations, which result in the production of full-length mutant p53 proteins. It has been reported that mutant p53 proteins and wild type p53 proteins often regulate same cellular biological processes with opposite effects. So, mutant p53 has been reported to supply the cancer cells of glucose and nutrients, and, to avoid reactive oxygen species (ROS) mediated damage during oxidative stress. These last features are able to render tumor cells resistant to ionizing radiations and chemotherapy. A future therapeutic approach in tumors bearing p53 mutations may be to deplete cancer cells of their energy reserves and antioxidants.

Anti-Oxidant, Pro-Oxidant and Anti-Inflammatory Effects of Unpolished Rice Relevant to Colorectal Cancer

Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rates. Carcinogenesis in the colon is a multistage and multifactorial process. An imbalance between free radical exposure and anti-oxidant defense systems may leads to oxidative stress and attack of macromolecules which can alter signal transduction pathways and gene expression. Consequently, oxidative damage can lead to cellular dysfunction and contribute to pathophysiological processes in a variety of diseases including CRC. One factor tightly associated with CRC is chronic inflammation, which can be present from the earliest stage of tumor onset. Unpolished rice is an attractive chemoprevention in CRC due to their anti-oxidant and anti-inflammatory activities. The aim of this paper is to review evidence linking oxidative stress and inflammation to CRC and to provide essential background information for understanding future research on oxidative stress and inflammation on CRC. Mechanisms of action of unpolished rice in CRC carcinogenesis are also discussed.

Prostate-Specific Membrane Antigen Targeted Polymersomes for Delivering Mocetinostat and Docetaxel to Prostate Cancer Cell Spheroids

Prostate cancer cells overexpress the prostate-specific membrane antigen (PSMA) receptors on the surface. Targeting the PSMA receptor creates a unique opportunity for drug delivery. Docetaxel is a Food and Drug Administration-approved drug for treating metastatic and androgen-independent prostate cancer, and mocetinostat is a potent inhibitor of class I histone deacetylases. In this study, we prepared reduction-sensitive polymersomes presenting folic acid on the surface and encapsulating either docetaxel or mocetinostat. The presence of folic acid allowed efficient targeting of the PSMA receptor and subsequent internalization of the polymeric vesicles in cultured LNCaP prostate cancer cell spheroids. The intracellular reducing agents efficiently released docetaxel and mocetinostat from the polymersomes. The combination of the two drug-encapsulated polymersome formulations significantly (p < 0.05) decreased the viability of the LNCaP cells (compared to free drugs or control) in three-dimensional spheroid cultures. The calculated combination index value indicated a synergistic effect for the combination of mocetinostat and docetaxel. Thus, our PSMA-targeted drug-encapsulated polymersomes has the potential to lead to a new direction in prostate cancer therapy that decreases the toxicity and increases the efficacy of the drug delivery systems.