Metallothionein 1G and zinc sensitize human colorectal cancer cells to chemotherapy

Zinc Oxide Nanoparticles and Cancer Chemotherapy: Helpful Tools for Enhancing Chemo-sensitivity and Reducing Side Effects?

Cancer chemotherapy is still a serious challenge. Chemo-resistance and destructive side effects of chemotherapy drugs are the most critical limitations of chemotherapy. Chemo-resistance is the leading cause of chemotherapy failure. Chemo-resistance, which refers to the resistance of cancer cells to the anticancer effects of chemotherapy drugs, is caused by various reasons. Among the most important of these reasons is the increase in the efflux of chemotherapy drugs due to the rise in the expression and activity of ABC transporters, the weakening of apoptosis, and the strengthening of stemness. In the last decade, a significant number of studies focused on the application of nanotechnology in cancer treatment. Considering the anti-cancer properties of zinc, zinc oxide nanoparticles have received much attention in recent years. Some studies have indicated that zinc oxide nanoparticles can target the critical mechanisms of cancer chemo-resistance and enhance the effectiveness of chemotherapy drugs. These studies have shown that zinc oxide nanoparticles can reduce the activity of ABC transporters, increase DNA damage and apoptosis, and attenuate stemness in cancer cells, leading to enhanced chemo-sensitivity. Some other studies have also shown that zinc oxide nanoparticles in low doses can be helpful in minimizing the harmful side effects of chemotherapy drugs. In this article, after a brief overview of the mechanisms of chemo-resistance and anticancer effects of zinc, we will review all these studies in detail.

Cellular zinc metabolism and zinc signaling: from biological functions to diseases and therapeutic targets

Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc's involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc's cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.

Tumor cell cytoplasmic metallothionein expression associates with differential tumor immunogenicity and prognostic outcome in high-grade serous ovarian carcinoma

Background

The underlying mechanism of high T-cell presence as a favorable prognostic factor in high-grade serous ovarian carcinoma (HGSOC) is not yet understood. In addition to immune cells, various cofactors are essential for immune processes. One of those are metallothioneins (MTs), metal-binding proteins comprising various isoforms. MTs play a role in tumor development and drug resistance. Moreover, MTs influence inflammatory processes by regulating zinc homeostasis. In particular, T-cell function and polarization are particularly susceptible to changes in zinc status. The aim of the present study was to investigate a possible role of MT-mediated immune response and its association with prognostic outcome in ovarian cancer.

Methods

A retrospective study was conducted on a clinically well-characterized cohort of 24 patients with HGSOC treated at the University Hospital of Essen. Gene expression patterns for anti-cancer immunogenicity-related targets were performed using the NanoString nCounter platform for digital gene expression analysis with the appurtenant PanCancer Immune Profiling panel, consisting of 770 targets and 30 reference genes. Tumor-associated immunohistochemical MT protein expression was evaluated using a semi-quantitative four-tier Immunohistochemistry (IHC) scoring.

Results

MT immunoexpression was detected in 43% (10/23) of all HGSOC samples. MT immunoexpression levels showed a significant association to survival, leading to prolonged progression-free and overall survival in positively stained tumors. Furthermore, T-cell receptor signaling gene signature showed a strong activation in MT-positive tumors. Activated downstream signaling cascades resulting in elevated interferon-gamma expression with a shift in the balance between T helper cells (TH1 and TH2) could be observed in the MT-positive subgroup. In addition, a higher expression pattern of perforin and several granzymes could be detected, overall suggestive of acute, targeted anti-cancer immune response in MT-positive samples.

Conclusion

This is the first study combining broad, digital mRNA screening of anti-tumor immune response-associated genes and their relation to MT-I/II in ovarian cancer. MT overexpression is associated with molecular characteristics of an anti-cancer immune response and is a strong prognostic marker in ovarian HGSOC. The observed immune cell activation associated with tumor MT expression comprises but is not limited to T cells and natural killer cells.

Determinants of Survival with Combined HER2 and PD-1 Blockade in Metastatic Esophagogastric Cancer

PURPOSE

We report updated clinical outcomes from a phase II study of pembrolizumab, trastuzumab, and chemotherapy (PTC) in metastatic esophagogastric cancer in conjunction with outcomes from an independent Memorial Sloan Kettering (MSK) cohort.

PATIENTS AND METHODS

The significance of pretreatment 89Zr-trastuzumab PET, plasma circulating tumor DNA (ctDNA) dynamics, and tumor HER2 expression and whole exome sequencing was evaluated to identify prognostic biomarkers and mechanisms of resistance in patients treated on-protocol with PTC. Additional prognostic features were evaluated using a multivariable Cox regression model of trastuzumab-treated MSK patients (n = 226). Single-cell RNA sequencing (scRNA-seq) data from MSK and Samsung were evaluated for mechanisms of therapy resistance.

RESULTS

89Zr-trastuzumab PET, scRNA-seq, and serial ctDNA with CT imaging identified how pre-treatment intrapatient genomic heterogeneity contributes to inferior progression-free survival (PFS). We demonstrated that the presence of intensely avid lesions by 89Zr-trastuzumab PET declines in tumor-matched ctDNA by 3 weeks, and clearance of tumor-matched ctDNA by 9 weeks were minimally invasive biomarkers of durable PFS. Paired pre- and on-treatment scRNA-seq identified rapid clearance of HER2-expressing tumor clones with expansion of clones expressing a transcriptional resistance program, which was associated with MT1H, MT1E, MT2A, and MSMB expression. Among trastuzumab-treated patients at MSK, ERBB2 amplification was associated with improved PFS, while alterations in MYC and CDKN2A/B were associated with inferior PFS.

CONCLUSIONS

These findings highlight the clinical relevance of identifying baseline intrapatient heterogeneity and serial ctDNA monitoring of HER2-positive esophagogastric cancer patients to identify early evidence of treatment resistance, which could guide proactive therapy escalation or deescalation.

Role of Combination Treatment of Aspirin and Zinc in DMH-DSS-induced Colon Inflammation, Oxidative Stress and Tumour Progression in Male BALB/c Mice

Colitis-associated colorectal cancer serves as a prototype of inflammation-associated cancers which is linked with repeated cycles of inflammation and DNA repair deficits. Several preclinical and clinical data reported that aspirin has a chemo-preventive effect in colorectal cancer and is associated with dose-dependent side effects. Furthermore, it has been reported that zinc supplementation improves the quality of life in patients undergoing chemotherapy by alteration of colonic cancer cell gene expression. However, explication of the detailed molecular mechanisms involved in the combined administration of aspirin and zinc-mediated protection against colitis-associated colorectal cancer deserves further investigation. For the induction of colitis-associated colorectal cancer, male BALB/c mice were administered 1,2-dimethylhydrazine dihydrochloride (DMH) 20 mg/kg/bw thrice before the initiation of every DSS cycle (3%w/v in drinking water). One week after the initiation of DSS treatment, aspirin (40 mg/kg; p.o.) and zinc in the form of zinc sulphate (3 mg/kg; p.o.) were administered for 8 weeks. Combination of aspirin and zinc as intervention significantly ameliorated DAI score, myeloperoxidase activity, histological score, apoptotic cells and protein expression of various inflammatory markers including nuclear factor kappa light chain enhancer of activated B cells (NFκBp65), cycloxygenase-2 (COX-2) and interleukin-6 (IL-6); proliferation markers such as proliferating cell nuclear antigen (PCNA), signal transducer and activator of transcription 3 (STAT3) expression significantly decreased, and antioxidant enzymes nuclear factor erythroid 2-related factor 2 (Nrf-2), metallothionein, catalase and superoxide dismutase (SOD) significantly increased as evaluated by immunohistochemistry and western blot analysis.

MiR-376a-3p increases cell apoptosis in acute myeloid leukemia by targeting MT1X

Metallothioneins (MTs) are a group of low-molecular weight cysteine-rich proteins that play vital roles in oxidative stress, metal homeostasis, carcinogenesis and drug resistance. However, few studies have analyzed the roles of MTs in acute myeloid leukemia (AML). In this study, we revealed that the expression of metallothionein1X (MT1X), a main isoform of MTs, was highly expressed and acted as a candidate of prognostic indicator in AML patients. In vitro cell function experiments verified that silencing MT1X inhibited the proliferation of AML cells, sensitized cells to doxorubicin, and increased their apoptosis. We also showed that the downregulation of MT1X expression suppressed nuclear factor-κB (NF-κB) signaling by reducing p65, p-IκB-α, and downstream effectors. Elevated p65 and MT1X levels were indicators in AML. Moreover, we revealed that miR-376a-3p had binding sites with 3'-UTR of MT1X, suggesting that MT1X was negatively regulated by miR-376a-3p. Cell functional assay results indicated that miR-376a-3p overexpression significantly inhibited the proliferation, arrested the AML cells in the G0/G1 phase and induced cell apoptosis. The rescue experiments further confirmed that miR-376a-3p could reverse the promotion of MT1X overexpression on the progress of AML cells. Taken together, our results revealed that elevated MT1X expression might be involved in the mechanism underlying AML progression, indicating that the miR-376a/MT1X axis might serve as a promising novel target for the effective treatment of patients with AML.

The crosstalk effect between ferrous and other ions metabolism in ferroptosis for therapy of cancer

Ferroptosis is an iron-dependent cell death process characterized by excessive accumulation of reactive oxygen species and lipid peroxidation. The elucidation of ferroptosis pathways may lead to novel cancer therapies. Current evidence suggests that the mechanism of ferroptosis can be summarized as oxidative stress and antioxidant defense mechanisms. During this process, ferrous ions play a crucial role in cellular oxidation, plasma membrane damage, reactive oxygen species removal imbalance and lipid peroxidation. Although, disregulation of intracellular cations (Fe²⁺, Ca²⁺, Zn²⁺, etc.) and anions (Cl^-, etc.) have been widely reported to be involved in ferroptosis, their specific regulatory mechanisms have not been established. To further understand the crosstalk effect between ferrous and other ions in ferroptosis, we reviewed the ferroptosis process from the perspective of ions metabolism. In addition, the role of ferrous and other ions in tumor therapy is briefly summarized.

Hierarchical mesoporous zinc-imidazole dicarboxylic acid MOFs: Surfactant-directed synthesis, pH-responsive degradation, and drug delivery

The surfactant template-directed solvothermal method was applied in the synthesis of hierarchical mesoporous zinc-imidazolate derivative metal-organic framework (mesoMOF), which was then utilized for active loading of cisplatin (cis-Pt). To fabricate mesoMOF, various amounts of the surfactant (cetyltrimethylammonium bromide: 0.1-0.3 g) and linker (citric acid: 0.05-0.15 g) were added to the reaction mixture, which resulted in different particle sizes and morphologies. MesoMOF quality attributes such as Specific surface area (SSA), total porous volume, and Barrett-Joyner-Halenda (BJH) pore diameter were also determined. At the optimum reaction condition, mesoMOF with a high surface area (1859 m²/g), pore diameter (14.13 nm) and total pore volume (0.314 cm³/g) was attained. In the next step, cis-Pt was actively loaded in the mesoMOF with a high loading capacity (28% w/w), which was remarkably superior to the microporous MOF. Interestingly, in mildly acidic pH (5.5), mesoMOF underwent degradation, resulting in a rapid release of cis-Pt. Cell viability and apoptosis induction assays confirmed the superiority of the cis-Pt loaded mesoMOF over free drug in a resistant ovarian tumor cell line (A2780cp). Altogether, due to their tunable size and morphology, pH-responsiveness, and acceptable tolerability in mice, the mesoMOFs can be regarded as an anti-cancer drug delivery system.

Anti-tumour activity of zinc ionophore pyrithione in human ovarian cancer cells through inhibition of proliferation and migration and promotion of lysosome-mitochondrial apoptosis

Zinc pyrithione (ZPT) is widely used as an antimicrobial. Zinc is a necessary trace element of the human whose homeostasis associated with several cancers. However, the anticancer effect of increased Zinc in ovarian cancer is still unclear. This study focussed on the anti-tumour effects of ZPT combined with Zinc in SKOV3 and SKOV3/DDP cells. The cell viability, apoptosis, migration, and invasion assays were detected by CCK-8, flow cytometry, wound healing and transwell assay, respectively. The distribution of Zinc in cells was monitored by staining of Zinc fluorescent dye and lysosome tracker. The changes in lysosomal membrane stability were reflected by acridine orange fluorescence and cathepsin D reposition. Expression of the proteins about invasion and apoptosis was evaluated by western blot. The results indicated that ZPT combined with Zinc could notably reduce cell viability, inhibit migration and invasion in SKOV3 and SKOV3/DDP cells. Besides, ZPT performed as a Zinc carrier targeted lysosomes, caused the increase of its membrane permeability and the release of cathepsin D accompanied by mitochondrial apoptosis in SKOV3/DDP cells. In conclusion, our work suggests that ZPT combined with Zinc could inhibit proliferation, migration, invasion, and promote apoptosis by trigger the lysosome-mitochondrial apoptosis pathway in ovarian carcinoma.

Metallothionein-1G suppresses pancreatic cancer cell stemness by limiting activin A secretion via NF-κB inhibition

Resistance to chemotherapy is a long-standing problem in the management of cancer, and cancer stem cells are regarded as the main source of this resistance. This study aimed to investigate metallothionein (MT)-1G involvement in the regulation of cancer stemness and provide a strategy to overcome chemoresistance in pancreatic ductal adenocarcinoma (PDAC). Methods: MT1G was identified as a critical factor related with gemcitabine resistance in PDAC cells by mRNA microarray. Its effects on PDAC stemness were evaluated through sphere formation and tumorigenicity. LC-MS/MS analysis of conditional medium revealed that activin A, a NF-κB target, was a major protein secreted from gemcitabine resistant PDAC cells. Both loss-of-function and gain-of-function approaches were used to validate that MT1G inhibited NF-κB-activin A pathway. Orthotopic pancreatic tumor model was employed to explore the effects on gemcitabine resistance with recombinant follistatin to block activin A. Results: Downregulation of MT1G due to hypermethylation of its promoter is related with pancreatic cancer stemness. Secretome analysis revealed that activin A, a NF-κB target, was highly secreted by drug resistant cells. It promotes pancreatic cancer stemness in Smad4-dependent or independent manners. Mechanistically, MT1G negatively regulates NF-κB signaling and promotes the degradation of NF-κB p65 subunit by enhancing the expression of E3 ligase TRAF7. Blockade of activin A signaling with follistatin could overcome gemcitabine resistance. Conclusions: MT1G suppresses PDAC stemness by limiting activin A secretion via NF-κB inhibition. The blockade of the activin A signaling with follistatin may provide a promising therapeutic strategy for overcoming gemcitabine resistance in PDAC.

Zinc, ω-3 polyunsaturated fatty acids and vitamin D: An essential combination for prevention and treatment of cancers

Zinc, ω-3 polyunsaturated fatty acids (PUFAs) and vitamin D are essential nutrients for health, maturation and general wellbeing. Extensive literature searches have revealed the widespread similarity in molecular biological properties of zinc, ω-3 PUFAs and vitamin D, and their similar anti-cancer properties, even though they have different modes of action. These three nutrients are separately essential for good health, especially in the aged. Zinc, ω-3 PUFAs and vitamin D are inexpensive and safe as they are fundamentally natural and have the properties of correcting and inhibiting undesirable actions without disturbing the normal functions of cells or their extracellular environment. This review of the anticancer properties of zinc, ω-3 PUFAs and vitamin D is made in the context of the hallmarks of cancer. The anticancer properties of zinc, ω-3 PUFAs and vitamin D can therefore be used beneficially through combined treatment or supplementation. It is proposed that sufficiency of zinc, ω-3 PUFAs and vitamin D is a necessary requirement during chemotherapy treatment and that clinical trials can have questionable integrity if this sufficiency is not checked and maintained during efficacy trials.

Proprotein convertases blockage up-regulates specifically metallothioneins coding genes in human colon cancer stem cells

Despite continuous exertion made, colon cancer still represents a major health problem and its incidence continues being high worldwide. There is growing evidence in support of the cancer stem cells (CSCs) being central in the initiation of this cancer, and CSCs have been the focus of various studies for the identification of new ways of treatment. Lately, the proprotein convertases (PCs) were reported to regulate the maturation and expression of various molecules involved in the malignant phenotype of colon cancer cells, however, the identity of the molecules regulated by these serine proteases in CSCs is unknown. In this study, we used the general PCs inhibitor, the Decanoyl-RVKR-chloromethylketone (Decanoyl-RVKR-CMK) that inhibits all the PCs found in the secretory pathway, and analyzed its effect on CSCs using RNA-seq analysis. Remarkably, from the only 9 up-regulated genes in the human SW620-derived sphere-forming cells, we identified 7 of the 11 human metallothioneins, all of them localized on chromosome 16, and zinc related proteins as downstream effectors of the PCs. The importance of these molecules in the regulation of cell proliferation, differentiation and chemoresistance, and their reported potential tumor suppressor role and loss in colon cancer patients associated with worse prognosis, suggests that targeting PCs in the control of the malignant phenotype of CSCs is a new potential therapeutic strategy in colon cancer.

Identification of Hub Genes Related to Carcinogenesis and Prognosis in Colorectal Cancer Based on Integrated Bioinformatics

The high mortality of colorectal cancer (CRC) patients and the limitations of conventional tumor-node-metastasis (TNM) stage emphasized the necessity of exploring hub genes closely related to carcinogenesis and prognosis in CRC. The study is aimed at identifying hub genes associated with carcinogenesis and prognosis for CRC. We identified and validated 212 differentially expressed genes (DEGs) from six Gene Expression Omnibus (GEO) datasets and the Cancer Genome Atlas (TCGA) database. We investigated functional enrichment analysis for DEGs. The protein-protein interaction (PPI) network was constructed, and hub modules and genes in CRC carcinogenesis were extracted. A prognostic signature was developed and validated based on Cox proportional hazards regression analysis. The DEGs mainly regulated biological processes covering response to stimulus, metabolic process, and affected molecular functions containing protein binding and catalytic activity. The DEGs played important roles in CRC-related pathways involving in preneoplastic lesions, carcinogenesis, metastasis, and poor prognosis. Hub genes closely related to CRC carcinogenesis were extracted including six genes in model 1 (CXCL1, CXCL3, CXCL8, CXCL11, NMU, and PPBP) and two genes and Metallothioneins (MTs) in model 2 (SLC26A3 and SLC30A10). Among them, CXCL8 was also related to prognosis. An eight-gene signature was proposed comprising AMH, WBSCR28, SFTA2, MYH2, POU4F1, SIX4, PGPEP1L, and PAX5. The study identified hub genes in CRC carcinogenesis and proposed an eight-gene signature with good reproducibility and robustness at the molecular level for CRC, which might provide directive significance for treatment selection and survival prediction.

Metallothionein isoforms as double agents - Their roles in carcinogenesis, cancer progression and chemoresistance

Metallothioneins (MTs) are small cysteine-rich intracellular proteins with four major isoforms identified in mammals, designated MT-1 through MT-4. The best known biological functions of MTs are their ability to bind and sequester metal ions as well as their active role in redox homeostasis. Despite these protective roles, numerous studies have demonstrated that changes in MT expression could be associated with the process of carcinogenesis and participation in cell differentiation, proliferation, migration, and angiogenesis. Hence, MTs have the role of double agents, i.e., working with and against cancer. In view of their rich biochemical properties, it is not surprising that MTs participate in the emergence of chemoresistance in tumor cells. Many studies have demonstrated that MT overexpression is involved in the acquisition of resistance to anticancer drugs including cisplatin, anthracyclines, tyrosine kinase inhibitors and mitomycin. The evidence is gradually increasing for a cellular switch in MT functions, showing that they indeed have two faces: protector and saboteur. Initially, MTs display anti-oncogenic and protective roles; however, once the oncogenic process was launched, MTs are utilized by cancer cells for progression, survival, and contribution to chemoresistance. The duality of MTs can serve as a potential prognostic/diagnostic biomarker and can therefore pave the way towards the development of new cancer treatment strategies. Herein, we review and discuss MTs as tumor disease markers and describe their role in chemoresistance to distinct anticancer drugs.

Diagnostic potential of ionomic profile in the plasma of cervical cancer patients receiving neoadjuvant chemoradiotherapy

BACKGROUND AND AIM

Major and trace elements play an important role in human body, and it has been reported that ionomic distribution differ greatly in tumor patients. The aim of the present study was to investigate the effects of cisplatin-based neoadjuvant chemoradiotherapy on the ionomic profile in human plasma as a potential biomarker for the therapeutic effects of cervical cancer.

METHOD

Thirty-seven patients with cervical cancer receiving neoadjuvant chemoradiotherapy were included in this study, pretherapy and post-treatment blood samples were collected and concentrations of 24 ions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

The results showed that after cisplatin chemotherapy and radiotherapy, patients' plasma Pt level significantly increased, Na, Mg, P, K, Ca, Se, Cu, Zn, Se, Sr, Ba levels significantly decreased (P < 0.01), and Al, Cu ions were significantly correlated with the treatment effect (P < 0.05). In addition, the pattern of elemental correlations changed dramatically after the neoadjuvant chemoradiotherapy.

CONCLUSION

The results indicated that the plasma ionomic profile may serve as a quick and convenient tool to reflect the therapeutic effect of cisplatin-based chemoradiotherapy in cervical cancer patients, and supplement of certain essential elements may be of great importance for the maintenance of ion homeostasis in human body and for the reduction of adverse effect of chemotherapy and radiotherapy.

Elemental Zn and its Binding Protein Zinc-α2-Glycoprotein are Elevated in HPV-Positive Oropharyngeal Squamous Cell Carcinoma

Human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) is biologically distinct from HPV-negative HNSCC. Outside of HPV-status, few tumor-intrinsic variables have been identified that correlate to improved survival. As part of exploratory analysis into the trace elemental composition of oropharyngeal squamous cell carcinoma (OPSCC), we performed elemental quanitification by X-ray fluorescence microscopy (XFM) on a small cohort (n = 32) of patients with HPV-positive and -negative OPSCC and identified in HPV-positive cases increased zinc (Zn) concentrations in tumor tissue relative to normal tissue. Subsequent immunohistochemistry of six Zn-binding proteins—zinc-α2-glycoprotein (AZGP1), Lipocalin-1, Albumin, S100A7, S100A8 and S100A9—revealed that only AZGP1 expression significantly correlated to HPV-status (p < 0.001) and was also increased in tumor relative to normal tissue from HPV-positive OPSCC tumor samples. AZGP1 protein expression in our cohort significantly correlated to a prolonged recurrence-free survival (p = 0.029), similar to HNSCC cases from the TCGA (n = 499), where highest AZGP1 mRNA levels correlated to improved overall survival (p = 0.023). By showing for the first time that HPV-positive OPSCC patients have increased intratumoral Zn levels and AZGP1 expression, we identify possible positive prognostic biomarkers in HNSCC as well as possible mechanisms of increased sensitivity to chemoradiation in HPV-positive OPSCC.

MT1G serves as a tumor suppressor in hepatocellular carcinoma by interacting with p53

Poor prognosis of hepatocellular carcinoma (HCC) patients is frequently associated with rapid tumor growth, recurrence and drug resistance. MT1G is a low-molecular weight protein with high affinity for zinc ions. In the present study, we investigated the expression of MT1G, analyzed clinical significance of MT1G, and we observed the effects of MT1G overexpression on proliferation and apoptosis of HCC cell lines in vitro and in vivo. Our results revealed that MT1G was significantly downregulated in tumor tissues, and could inhibit the proliferation as well as enhance the apoptosis of HCC cells. The mechanism study suggested that MT1G increased the stability of p53 by inhibiting the expression of its ubiquitination factor, MDM2. Furthermore, MT1G also could enhance the transcriptional activity of p53 through direct interacting with p53 and providing appropriate zinc ions to p53. The modulation of MT1G on p53 resulted in upregulation of p21 and Bax, which leads cell cycle arrest and apoptosis, respectively. Our in vivo assay further confirmed that MT1G could suppress HCC tumor growth in nude mice. Overall, this is the first report on the interaction between MT1G and p53, and adequately uncover a new HCC suppressor which might have therapeutic values by diminishing the aggressiveness of HCC cells.

The transcriptome difference between colorectal tumor and normal tissues revealed by single-cell sequencing

The previous cancer studies were difficult to reproduce since the tumor tissues were analyzed directly. But the tumor tissues were actually a mixture of different cancer cells. The transcriptome of single-cell was much robust than the transcriptome of a mixed tissue. The single-cell transcriptome had much smaller variance. In this study, we analyzed the single-cell transcriptome of 272 colorectal cancer (CRC) epithelial cells and 160 normal epithelial cells and identified 342 discriminative transcripts using advanced machine learning methods. The most discriminative transcripts were LGALS4, PHGR1, C15orf48, HEPACAM2, PERP, FABP1, FCGBP, MT1G, TSPAN1 and CKB. We further clustered the 342 transcripts into two categories. The upregulated transcripts in CRC epithelial cells were significantly enriched in Ribosome, Protein processing in endoplasmic reticulum, Antigen processing and presentation and p53 signaling pathway. The downregulated transcripts in CRC epithelial cells were significantly enriched in Mineral absorption, Aldosterone-regulated sodium reabsorption and Oxidative phosphorylation pathways. The biological analysis of the discriminative transcripts revealed the possible mechanism of colorectal cancer.

Zn(II)-curcumin solid dispersion impairs hepatocellular carcinoma growth and enhances chemotherapy by modulating gut microbiota-mediated zinc homeostasis

Zinc(II) complexes of curcumin display moderate cytotoxicity towards cancer cells at low micromolar concentrations. However, the clinical use of zinc(II) complexes is hampered by hydrolytic insolubility and poor bioavailability and their anticancer mechanisms remain unclear. Here, we investigated the efficacy and mechanism of action of a polyvinylpyrrolidone (PVP-k30)-based solid dispersion of Zn(II)-curcumin (ZnCM-SD) against hepatocellular carcinoma (HCC) in vitro and in vivo. In vitro assays revealed ZnCM-SD not only reduced the viability of HepG2 cells and SK-HEP1 cells in a dose-dependent manner, but also potently and synergistically enhanced cell growth inhibition and cell death in response to doxorubicin by regulating cellular zinc homeostasis. ZnCM-SD was internalized into the cells via non-specific endocytosis and degraded to release curcumin and Zn²⁺ ions within cells. The anticancer effects also occur in vivo in animals following the oral administration of ZnCM-SD, without significantly affecting the weight of the animals. Interestingly, ZnCM-SD did not reduce tumor growth or affect zinc homeostasis in HepG2-bearing mice after gut microbiome depletion. Moreover, administration of ZnCM-SD alone or in combination with doxorubicin significantly attenuated gut dysbiosis and zinc dyshomeostasis in a rat HCC model. Notably, fecal microbiota transplantation revealed the ability of ZnCM-SD to regulate zinc homeostasis and act as a chemosensitizer for doxorubicin were dependent on the gut microbiota. The crucial role of the gut microbiota in the chemosensitizing ability of ZnCM-SD was confirmed by broad-spectrum antibiotic treatment. Collectively, ZnCM-SD could represent a simple, well-tolerated, safe, effective therapy and function as a novel chemosensitizing agent for cancer.

Overexpressed long noncoding RNA TUG1 affects the cell cycle, proliferation, and apoptosis of pancreatic cancer partly through suppressing RND3 and MT2A

Background

Long noncoding RNAs (lncRNAs) are involved in various human diseases, including cancers. However, their mechanisms remain undocumented. We investigated alterations in lncRNA that may be related to pancreatic cancer (PC) through analysis of microarray data.

Methods

In the present study, quantitative real-time PCR analysis was used to examine the expression of taurine upregulated 1 (TUG1) in PC tissue samples and PC cell lines. In PC cell lines, MTT assays, colony formation assays, and flow cytometry were used to investigate the effects of TUG1 on proliferation, cell cycle regulation, and apoptosis. Moreover, we established a xenograft model to assess the effect of TUG1 on tumor growth in vivo. The molecular mechanism of potential target genes was detected through nuclear separation experiments, RNA immunoprecipitation (RIP), chromatin immunoprecipitation assays (ChIP), and other experimental methods.

Results

The findings suggest that the abnormally high expression of TUG1 in PC tissues was associated with tumor size and pathological stage. Knockdown of TUG1 blocked the cell cycle and accelerated apoptosis, thereby inhibiting the proliferation of PC cells. In addition, RIP experiments showed that TUG1 can recruit enhancer of zeste homolog 2 (EZH2) to the promoter regions of Rho family GTPase 3 (RND3) and metallothionein 2A (MT2A) and inhibit their expression at the transcriptional level. Furthermore, ChIP experiments demonstrated that EZH2 could bind to the promoter regions of RND3 and MT2A. The knockdown of TUG1 reduced this binding capacity.

Conclusion

In conclusion, our data suggest that TUG1 may regulate the expression of PC-associated tumor suppressor genes at the transcriptional level and these may become potential targets for the diagnosis and treatment of PC.

Role of Zinc and Selenium in Oxidative Stress and Immunosenescence: Implications for Healthy Aging and Longevity

Aging is a complex process that includes gradual and spontaneous biochemical and physiological changes which contributes to a decline in performance and increased susceptibility to diseases. Zn and Se are essential trace elements that play a pivotal role in immune functions and antioxidant defense and, consequently, are claimed to play also a role in successful aging trajectories. Consistently with their nature of essential trace elements, a plethora of data obtained “in vitro” and “in vivo” (in humans and animal models) support the relevance of Zn and Se for both the innate and adoptive immune response. Moreover, Zn and Se are strictly involved in the synthesis and regulation of activity of proteins and enzymes, e.g., metallothioneins (MT) and glutathione peroxidase (GPX), that are necessary for our endogenous antioxidant response. This is clearly important to protect our cells from oxidative damage and to slow the decline of our immune system with aging. Age-related changes affecting tissue levels of Zn and Se may indicate that the risk of Zn and Se deficiency increases with aging. However, it is still unclear which of these changes can be the consequence of a “real deficiency” and which can be part of our physiological compensatory response to the accumulating damage occurring in aging. Furthermore, the upregulation of antioxidant proteins (Zn and Se dependent) may be a manifestation of self-induced oxidative stress. By the way, Zn and Se dependent proteins are modulated not only by nutritional status, but also by well-known hallmarks of aging that play antagonistic functions, such as the deregulated nutrient sensing pathways and cellular senescence. Thus, it is not an easy task to conduct Zn or Se supplementation in elderly and it is emerging consistent that these kind of supplementation requires an individualized approach. Anyway, there is consistent support that supplementation with Zn using doses around 10 mg/day is generally safe in elderly and may even improve part of immune performances in those subjects with a baseline deficiency. Regarding Se supplementation, it may induce both beneficial and detrimental effects on cellular immunity depending on the form of Se, supplemental dose, and delivery matrix. The nutritional association of supplements based on “Zn plus Se” is hypothesized to provide additional benefits, but this will likely need a more complex individualized approach. The improvement of our knowledge around screening and detection of Zn and Se deficiency in aging could lead to substantial benefits in terms of efficacy of nutritional supplements aimed at ameliorate performance and health in aging.

Expression of Metallothionein after Administration of Aspirin, Vitamin C or Zinc Supplement in the DMH Induced Colon Carcinoma in Rat

Background:

Chemoprevention refers to the use of specificnatural or synthetic chemical agents to suppress the development and progression to carcinoma. The purpose of this study was to assess the effect of aspirin, vitamin C or zinc on the metallothionein (MT) mRNA gene expression as well as MT protein content byimmunohistochemistry andradioimmunoassay (RIA) in 1, 2-dimethyl hydrazine (DMH) induced cancerous colonic tissuein rats.

Methods:

Rats were randomly divided into three groups, group 1 (aspirin), group 2 (vitamin C) group 3 (zinc), each of which was further sub divided into two groups and given subcutaneous injections of DMH (30 mg/kg body weight) twice a week for 3 months and sacrificed at either 4 months (A-precancer model) or at 6 months (B-cancer model). The control groups were administered 0.5 ml saline subcutaneously. All the 3 groups were simultaneouslyadministered aspirin, vitamin Cor zinc supplement respectively from the beginning till the end of the study.

Results:

It was observed that rats co-treated with aspirin, vitamin C or zinc resulted in a significant increase in the colonic MT mRNA expression in the precancer and cancer model as compared to the saline only controls. MT protein expression showed a 60%, 64% and 78% immunopositivity in the co-treated groups respectively. The mean MT content in the precancer and the cancer model was restored to near normal levels in all the three co-treated groups.

Conclusion:

These results suggest that co-administration of aspirin, vitamin C or zinc resulted in a significant increase in MT mRNA gene expression, MT protein expression and MT protein content which could possibly be one of the reasons for a chemo protective effect against progression to colonic cancer in a chemically induced DMH model in rat. Zinc supplement had a greater effect on metallothionein expression than aspirin or vitamin C.

Metallothionein 1 family profiling identifies MT1X as a tumor suppressor involved in the progression and metastastatic capacity of hepatocellular carcinoma

Metallothionein 1 (MT1s) is a family of cysteine-rich proteins with diverse functions such as metal homeostasis, oxidative stress, and carcinogenesis. However, its involvement in hepatocellular carcinoma (HCC) remains not fully understood. We aimed to explore the contribution of the individual member of MT1s to HCC. Its member mRNA levels were determined in cohort 1 of normal (n = 30), cirrhotic (n = 30), peritumoral (n = 135), and HCC (n = 135). In cohort 1, seven of eight members were down-regulated during the transition from normal liver to HCC, and only MT1G and MT1X were correlated with tumor features and outcomes. The MT1X was selected to be further stained in cohort 2 consisting of a series of liver nodules (15 normal livers, 33 cirrhotic livers, 12 dysplastic nodules, 31 HCC, and 9 HCC metastasis), and in cohort 3 (HCC, n = 85). In cohort 2, MT1X immunoreactivity was reduced in HCC and lost in metastatic HCC and showed good diagnostic performance for HCC (AUC = 0.754, 95%IC = 0.659-0.849). In cohort 3, MT1X expression in peritumoral tissues was independent predictor for HCC (recurrence free survival: HR = 0.34, 95%CI = 0.17-0.66; overall survival: HR = 0.32, 95%CI = 0.16-0.60). Moreover, we found that ectopic overexpression of MT1X delayed G1/S progression of cell cycle and promoted apoptosis in HCC cells in vitro, and suppressed tumor growth and lung metastasis in nude mice in vivo. We further demonstrated that MT1X induces cell cycle arrest and apoptosis by inactivating NF-κB signaling in HCC. In conclusion, MT1X may serve as a candidate of prognostic indicator and inhibits the progression and metastasis of HCC.

The roles of metallothioneins in carcinogenesis

Metallothioneins (MTs) are small cysteine-rich proteins that play important roles in metal homeostasis and protection against heavy metal toxicity, DNA damage, and oxidative stress. In humans, MTs have four main isoforms (MT1, MT2, MT3, and MT4) that are encoded by genes located on chromosome 16q13. MT1 comprises eight known functional (sub)isoforms (MT1A, MT1B, MT1E, MT1F, MT1G, MT1H, MT1M, and MT1X). Emerging evidence shows that MTs play a pivotal role in tumor formation, progression, and drug resistance. However, the expression of MTs is not universal in all human tumors and may depend on the type and differentiation status of tumors, as well as other environmental stimuli or gene mutations. More importantly, the differential expression of particular MT isoforms can be utilized for tumor diagnosis and therapy. This review summarizes the recent knowledge on the functions and mechanisms of MTs in carcinogenesis and describes the differential expression and regulation of MT isoforms in various malignant tumors. The roles of MTs in tumor growth, differentiation, angiogenesis, metastasis, microenvironment remodeling, immune escape, and drug resistance are also discussed. Finally, this review highlights the potential of MTs as biomarkers for cancer diagnosis and prognosis and introduces some current applications of targeting MT isoforms in cancer therapy. The knowledge on the MTs may provide new insights for treating cancer and bring hope for the elimination of cancer.

An insight into the complex roles of metallothioneins in malignant diseases with emphasis on (sub)isoforms/isoforms and epigenetics phenomena

Metallothioneins (MTs) belong to a group of small cysteine-rich proteins that are ubiquitous throughout all kingdoms. The main function of MTs is scavenging of free radicals and detoxification and homeostating of heavy metals. In humans, 16 genes localized on chromosome 16 have been identified to encode four MT isoforms labelled by numbers (MT-1-MT-4). MT-2, MT-3 and MT-4 proteins are encoded by a single gene. MT-1 comprises many (sub)isoforms. The known active MT-1 genes are MT-1A, -1B, -1E, -1F, -1G, -1H, -1M and -1X. The rest of the MT-1 genes (MT-1C, -1D, -1I, -1J and -1L) are pseudogenes. The expression and localization of individual MT (sub)isoforms and pseudogenes vary at intra-cellular level and in individual tissues. Changes in MT expression are associated with the process of carcinogenesis of various types of human malignancies, or with a more aggressive phenotype and therapeutic resistance. Hence, MT (sub)isoform profiling status could be utilized for diagnostics and therapy of tumour diseases. This review aims on a comprehensive summary of methods for analysis of MTs at (sub)isoforms levels, their expression in single tumour diseases and strategies how this knowledge can be utilized in anticancer therapy.

Oxidative stress management in the hair follicle: Could targeting NRF2 counter age-related hair disorders and beyond?

Widespread expression of the transcription factor, nuclear factor (erythroid-derived 2)-like 2 (NRF2), which maintains redox homeostasis, has recently been identified in the hair follicle (HF). Small molecule activators of NRF2 may therefore be useful in the management of HF pathologies associated with redox imbalance, ranging from HF greying and HF ageing via androgenetic alopecia and alopecia areata to chemotherapy-induced hair loss. Indeed, NRF2 activation has been shown to prevent peroxide-induced hair growth inhibition. Multiple parameters can increase the levels of reactive oxygen species in the HF, for example melanogenesis, depilation-induced trauma, neurogenic and autoimmune inflammation, toxic drugs, environmental stressors such as UV irradiation, genetic defects and aging-associated mitochondrial dysfunction. In this review, the potential mechanisms whereby NRF2 activation could prove beneficial in treatment of redox-associated HF disorders are therefore discussed.

Metabolic inhibitors accentuate the anti-tumoral effect of HDAC5 inhibition

The US FDA approval of broad-spectrum histone deacetylase (HDAC) inhibitors has firmly laid the cancer community to explore HDAC inhibition as a therapeutic approach for cancer treatment. Hitting one HDAC member could yield clinical benefit but this required a complete understanding of the functions of the different HDAC members. Here we explored the consequences of specific HDAC5 inhibition in cancer cells. We demonstrated that HDAC5 inhibition induces an iron-dependent reactive oxygen species (ROS) production, ultimately leading to apoptotic cell death as well as mechanisms of mitochondria quality control (mitophagy and mitobiogenesis). Interestingly, adaptation of HDAC5-depleted cells to oxidative stress passes through reprogramming of metabolic pathways towards glucose and glutamine. Therefore, interference with both glucose and glutamine supply in HDAC5-inhibited cancer cells significantly increases apoptotic cell death and reduces tumour growth in vivo; providing insight into a valuable clinical strategy combining the selective inhibition of HDAC5 with various inhibitors of metabolism as a new therapy to kill cancer cells.

Metallothionein 1G promotes the differentiation of HT-29 human colorectal cancer cells

Metallothioneins (MTs) are a family of low- molecular-weight, cysteine-rich proteins involved in zinc and redox metabolism, that are epigenetically downregulated during colorectal cancer (CRC) progression, but may be re-induced with a variety of agents. Since loss of MT expression is associated with a worse prognosis, in the present study we investigated the effects of overexpression of the most significantly downregulated isoform in CRC, namely MT1G, on the HT-29 cell line. Overexpression of MT1G resulted in xenograft tumors with an aberrant morphology, characterized by an evident increase in mucin-containing cells that were identified as goblet cells under electron microscopy. Immunohistochemical detection of CDX2 and cytokeratin 20 was also increased, as were goblet-cell and enterocyte-specific genes by qRT-PCR. Microarray analysis of gene expression confirmed the alteration of several differentiation signaling pathways, including the Notch pathway. Using sodium butyrate and post-confluent growth as inducers of differentiation, we demonstrated that MT1G does indeed play a functional role in promoting goblet over enterocyte differentiation in vitro. Labile zinc is also induced upon differentiation of CRC cells, functionally contributing to enterocyte over goblet differentiation, as revealed using zinc-specific chelating agents. Overall, our results uncover a new tumor-suppressor activity of MT1G in promoting the differentiation of at least some CRC tumors, and implicate MTs and zinc signaling as new players in colorectal differentiation. This further contributes to the hypothesis that re-induction of MTs may have therapeutic value by diminishing the aggressiveness of CRC tumors.

Decreased zinc in the development and progression of malignancy: an important common relationship and potential for prevention and treatment of carcinomas

INTRODUCTION

Efficacious chemotherapy does not exist for treatment or prevention of prostate, liver, and pancreatic carcinomas, and some other cancers that exhibit decreased zinc in malignancy. Zinc treatment offers a potential solution; but its support has been deterred by adverse bias. Areas covered: 1. The clinical and experimental evidence for the common ZIP transporter/Zn down regulation in these cancers. 2. The evidence for a zinc approach to prevent and/or treat these carcinomas. 3. The issues that introduce bias against support for the zinc approach. Expert opinion: ZIP/Zn downregulation is a clinically established common event in prostate, hepatocellular and pancreatic cancers. 2. Compelling evidence supports the plausibility that a zinc treatment regimen will prevent development of malignancy and termination of progressing malignancy in these cancers; and likely other carcinomas that exhibit decreased zinc. 3. Scientifically-unfounded issues that oppose this ZIP/Zn relationship have introduced bias against support for research and funding of a zinc treatment approach. 4. The clinically-established and supporting experimental evidence provide the scientific credibility that should dictate the support for research and funding of a zinc approach for the treatment and possible prevention of these cancers. 5. This is in the best interest of the medical community and the public-at-large.

ZnCl2 sustains the adriamycin-induced cell death inhibited by high glucose

Hyperglycemia, the condition of high blood glucose, is typical of diabetes and obesity and represents a significant clinical problem. The relationship between hyperglycemia and cancer risk has been established by several studies. Moreover, hyperglycemia has been shown to reduce cancer cell response to therapies, conferring resistance to drug-induced cell death. Therefore, counteracting the negative effects of hyperglycemia may positively improve the cancer cell death induced by chemotherapies. Recent studies showed that zinc supplementation may have beneficial effects on glycemic control. Here we aimed at evaluating whether ZnCl2 could counteract the high-glucose (HG) effects and consequently restore the drug-induced cancer cell death. At the molecular level we found that the HG-induced expression of genes known to be involved in chemoresistance (such as HIF-1α, GLUT1, and HK2 glycolytic genes, as well as NF-κB activity) was reduced by ZnCl2 treatment. In agreement, the adryamicin (ADR)-induced apoptotic cancer cell death was significantly impaired by HG and efficiently re-established by ZnCl2 cotreatment. Mechanistically, the ADR-induced c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) phosphorylation, inhibited by HG, was efficiently restored by ZnCl2. The JNK involvement in apoptotic cell death was assessed by the use of JNK dominant-negative expression vector that indeed impaired the ZnCl2 ability to restore drug-induced cell death in HG condition. Altogether, these findings indicate that ZnCl2 supplementation efficiently restored the drug-induced cancer cell death, inhibited by HG, by both sustaining JNK activation and counteracting the glycolytic pathway.

Tumour-initiating cell-specific miR-1246 and miR-1290 expression converge to promote non-small cell lung cancer progression

The tumour-initiating cell (TIC) model accounts for phenotypic and functional heterogeneity among tumour cells. MicroRNAs (miRNAs) are regulatory molecules frequently aberrantly expressed in cancers, and may contribute towards tumour heterogeneity and TIC behaviour. More recent efforts have focused on miRNAs as diagnostic or therapeutic targets. Here, we identified the TIC-specific miRNAs, miR-1246 and miR-1290, as crucial drivers for tumour initiation and cancer progression in human non-small cell lung cancer. The loss of either miRNA impacted the tumour-initiating potential of TICs and their ability to metastasize. Longitudinal analyses of serum miR-1246 and miR-1290 levels across time correlate their circulating levels to the clinical response of lung cancer patients who were receiving ongoing anti-neoplastic therapies. Functionally, direct inhibition of either miRNA with locked nucleic acid administered systemically, can arrest the growth of established patient-derived xenograft tumours, thus indicating that these miRNAs are clinically useful as biomarkers for tracking disease progression and as therapeutic targets.

miRNAs can function either as proto-oncogenes or tumour suppressors in several cancers; however their function in tumour initiating cells is unclear. Here, Zhang et al. show that tumour initiating cell-specific miR-1246 and miR-1290 promote lung cancer initiation and metastasis and could serve as prognostic markers.

Epigenetic Upregulation of Metallothionein 2A by Diallyl Trisulfide Enhances Chemosensitivity of Human Gastric Cancer Cells to Docetaxel Through Attenuating NF-κB Activation

AIMS

Metallothionein 2A (MT2A) and nuclear factor-kappaB (NF-κB) are both involved in carcinogenesis and cancer chemosensitivity. We previously showed decreased expression of MT2A and IκB-α in human gastric cancer (GC) associated with poor prognosis of GC patients. The present study investigated the effect of diallyl trisulfide (DATS), a garlic-derived compound, and docetaxel (DOC) on regulation of MT2A in relation to NF-κB in GC cells.

RESULTS

DATS attenuated NF-κB signaling in GC cells, resulting in G2/M cell cycle arrest and apoptosis, culminating in the inhibition of cell proliferation and tumorigenesis in nude mice. The anti-GC effect of DATS was attributable to its capacity to epigenetically upregulate MT2A, which in turn enhanced transcription of IκB-α to suppress NF-κB activation in GC cells. The combination of DATS with DOC exhibited a synergistic anti-GC activity accompanied by MT2A upregulation and NF-κB inactivation. Histopathologic analysis of GC specimens from patients showed a significant increase in MT2A expression following DOC treatment. GC patients with high MT2A expression in tumor specimens showed significantly improved response to chemotherapy and prolonged survival compared with those with low MT2A expression in tumors.

INNOVATION AND CONCLUSION

We conclude that DATS exerts its anti-GC activity and enhances chemosensitivity of GC to DOC by epigenetic upregulation of MT2A to attenuate NF-κB signaling. Our findings delineate a mechanistic basis of MT2A/NF-κB signaling for DATS- and DOC-mediated anti-GC effects, suggesting that MT2A may be a chemosensitivity indicator in GC patients receiving DOC-based treatment and a promising target for more effective treatment of GC by combination of DATS and DOC. Antioxid. Redox Signal. 24, 839-854.

Metallothionein-1 as a biomarker of altered redox metabolism in hepatocellular carcinoma cells exposed to sorafenib

BACKGROUND

Sorafenib, a kinase inhibitor active against various solid tumours, induces oxidative stress and ferroptosis, a new form of oxidative necrosis, in some cancer cells. Clinically-applicable biomarkers that reflect the impact of sorafenib on the redox metabolism of cancer cells are lacking.

METHODS

We used gene expression microarrays, real-time PCR, immunoblot, protein-specific ELISA, and gene reporter constructs encoding the enzyme luciferase to study the response of a panel of cancer cells to sorafenib. Tumour explants prepared from surgical hepatocellular carcinoma (HCC) samples and serum samples obtained from HCC patients receiving sorafenib were also used.

RESULTS

We observed that genes of the metallothionein-1 (MT1) family are induced in the HCC cell line Huh7 exposed to sorafenib. Sorafenib increased the expression of MT1G mRNA in a panel of human cancer cells, an effect that was not observed with eight other clinically-approved kinase inhibitors. We identified the minimal region of the MT1G promoter that confers inducibility by sorafenib to a 133 base pair region containing an Anti-oxidant Response Element (ARE) and showed the essential role of the transcription factor NRF2 (Nuclear factor erythroid 2-Related Factor 2). We examined the clinical relevance of our findings by analysing the regulation of MT1G in five tumour explants prepared from surgical HCC samples. Finally, we showed that the protein levels of MT1 increase in the serum of some HCC patients receiving sorafenib, and found an association with reduced overall survival.

CONCLUSION

These findings indicate that MT1 constitute a biomarker adapted for exploring the impact of sorafenib on the redox metabolism of cancer cells.

Theranostic multimodular potential of zinc-doped ferrite-saturated metal-binding protein-loaded novel nanocapsules in cancers

The present study successfully developed orally deliverable multimodular zinc (Zn) iron oxide (Fe3O4)-saturated bovine lactoferrin (bLf)-loaded polymeric nanocapsules (NCs), and evaluated their theranostic potential (antitumor efficacy, magnetophotothermal efficacy and imaging capability) in an in vivo human xenograft CpG-island methylator phenotype (CIMP)-1(+)/CIMP2(-)/chromosome instability-positive colonic adenocarcinoma (Caco2) and claudin-low, triple-negative (ER(-)/PR(-)/HER2(-); MDA-MB-231) breast cancer model. Mice fed orally on the Zn-Fe-bLf NC diet showed downregulation in tumor volume and complete regression in tumor volume after 45 days of feeding. In human xenograft colon cancer, vehicle-control NC diet-group (n=5) mice showed a tumor volume of 52.28±11.55 mm(3), and Zn-Fe-bLf NC diet (n=5)-treated mice had a tumor-volume of 0.10±0.073 mm(3). In the human xenograft breast cancer model, Zn-Fe-bLf NC diet (n=5)-treated mice showed a tumor volume of 0.051±0.062 mm(3) within 40 days of feeding. Live mouse imaging conducted by near-infrared fluorescence imaging of Zn-Fe-bLf NCs showed tumor site-specific localization and regression of colon and breast tumor volume. Ex vivo fluorescence-imaging analysis of the vital organs of mice exhibited sparse localization patterns of Zn-Fe-bLf NCs and also confirmed tumor-specific selective localization patterns of Zn-Fe-bLf NCs. Dual imaging using magnetic resonance imaging and computerized tomography scans revealed an unprecedented theranostic ability of the Zn-Fe-bLf NCs. These observations warrant consideration of multimodular Zn-Fe-bLf NCs for real-time cancer imaging and simultaneous cancer-targeted therapy.

Reactive oxygen species mediate oxaliplatin-induced epithelial-mesenchymal transition and invasive potential in colon cancer

Therapeutic benefits offered by common chemotherapy drugs, such as oxaliplatin, are limited due to the development of resistance, which contributes to treatment failure and metastasis. The epithelial-mesenchymal transition (EMT) is a key event contributing to the development of resistance to chemotherapeutics. Although the relationship between oxaliplatin and chemotherapy resistance has been described for decades, the molecular mechanisms have remained elusive. The aim of the present study was to investigate the underlying mechanisms of oxaliplatin-mediated metastasis. Here, we identify reactive oxygen species (ROS) as mediators that promote the oxaliplatin-induced EMT. Following oxaliplatin treatment, the messenger RNA (mRNA) levels of most peroxiredoxin family genes, except for peroxiredoxin 1 (prdx1) gene, were constant or even decreased, resulting in ROS abundance. And the antioxidant guardian Nrf2 was unconspicuously raised both transcriptionally and translationally with oxaliplatin treatment as compared to those induced by topotecan treatment, which has been proved with no induced metastasis. In addition, the study evaluated high levels of ROS leading to EMT via activation of the known oncogenes Akt and Snail. Using the Akt inhibitor LY294002 or knocking down Snail expression via RNA interference (RNAi) reversed the effects of oxaliplatin on the EMT and metastasis. Our studies establish a role for the ROS-Akt-Snail axis as a mechanism by which chemotherapeutics induce EMT and cancer metastasis.

SPINK1 promotes colorectal cancer progression by downregulating Metallothioneins expression

Colorectal cancer (CRC) is the third most common cancer in the world, and second leading cause of cancer deaths in the US. Although, anti-EGFR therapy is commonly prescribed for CRC, patients harboring mutations in KRAS or BRAF show poor treatment response, indicating an ardent demand for new therapeutic targets discovery. SPINK1 (serine peptidase inhibitor, Kazal type 1) overexpression has been identified in many cancers including the colon, lung, breast and prostate. Our study demonstrates the functional significance of SPINK1 in CRC progression and metastases. Stable knockdown of SPINK1 significantly decreases cell proliferation, invasion and soft agar colony formation in the colon adenocarcinoma WiDr cells. Conversely, an increase in these oncogenic phenotypes was observed on stimulation with SPINK1-enriched conditioned media (CM) in multiple benign models such as murine colonic epithelial cell lines, MSIE and YAMC (SPINK3-negative). Mechanistically, SPINK1 promotes tumorigenic phenotype by activating phosphatidylinositol 3-kinase (PI3K/AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways, and the SPINK1-positive WiDr cells are sensitive to AKT and MEK inhibitors. Importantly, SPINK1 silencing mediated upregulation of various Metallothionein isoforms, considered as tumor suppressors in CRC, confer sensitivity to doxorubicin, which strengthens the rationale for using the combinatorial treatment approach for the SPINK1-positive CRC patients. Furthermore, in vivo studies using chicken chorioallantoic membrane assay, murine xenograft studies and metastasis models further suggest a pivotal role of SPINK1 in CRC progression and metastasis. Taken together, our study demonstrates an important role for the overexpressed SPINK1 in CRC disease progression, a phenomenon that needs careful evaluation towards effective therapeutic target development.