Manganese superoxide dismutase is a promising target for enhancing chemosensitivity of basal-like breast carcinoma

Exploring the underlying pharmacological, immunomodulatory, and anti-inflammatory mechanisms of phytochemicals against wounds: a molecular insight

BACKGROUND

Numerous cellular, humoral, and molecular processes are involved in the intricate process of wound healing.

PHARMACOLOGICAL RELEVANCE

Numerous bioactive substances, such as ß-sitosterol, tannic acid, gallic acid, protocatechuic acid, quercetin, ellagic acid, and pyrogallol, along with their pharmacokinetics and bioavailability, have been reviewed. These phytochemicals work together to promote angiogenesis, granulation, collagen synthesis, oxidative balance, extracellular matrix (ECM) formation, cell migration, proliferation, differentiation, and re-epithelialization during wound healing.

FINDINGS AND NOVELTY

To improve wound contraction, this review delves into how the application of each bioactive molecule mediates with the inflammatory, proliferative, and remodeling phases of wound healing to speed up the process. This review also reveals the underlying mechanisms of the phytochemicals against different stages of wound healing along with the differentiation of the in vitro evidence from the in vivo evidence There is growing interest in phytochemicals, or plant-derived compounds, due their potential health benefits. This calls for more scientific analysis and mechanistic research. The various pathways that these phytochemicals control/modulate to improve skin regeneration and wound healing are also briefly reviewed. The current review also elaborates the immunomodulatory modes of action of different phytochemicals during wound repair.

Research progress on the role of reactive oxygen species in the initiation, development and treatment of breast cancer

According to international cancer data, breast cancer (BC) is the leading type of cancer in women. Although significant progress has been made in treating BC, metastasis and drug resistance continue to be the primary causes of mortality for many patients. Reactive oxygen species (ROS) play a dual role in vivo: normal levels can maintain the body's normal physiological function; however, high levels of ROS below the toxicity threshold can lead to mtDNA damage, activation of proto-oncogenes, and inhibition of tumor suppressor genes, which are important causes of BC. Differences in the production and regulation of ROS in different BC subtypes have important implications for the development and treatment of BC. ROS can also serve as an important intracellular signal transduction factor by affecting the antioxidant system, activating MAPK and PI3K/AKT, and other signal pathways to regulate cell cycle and change the relationship between cells and the activity of metalloproteinases, which significantly impacts the metastasis of BC. Hypoxia in the BC microenvironment increases ROS production levels, thereby inducing the expression of hypoxia inducible factor-1α (HIF-1α) and forming "ROS- HIF-1α-ROS" cycle that exacerbates BC development. Many anti-BC therapies generate sufficient toxic ROS to promote cancer cell apoptosis, but because the basal level of ROS in BC cells exceeds that of normal cells, this leads to up-regulation of the antioxidant system, drug efflux, and apoptosis inhibition, rendering BC cells resistant to the drug. ROS crosstalks with tumor vessels and stromal cells in the microenvironment, increasing invasiveness and drug resistance in BC.

A superoxide-driven redox state promotes geroconversion and resistance to senolysis in replication-stress associated senescence

Using S-phase synchronized RPE1-hTERT cells exposed to the DNA damaging agent, methyl methanesulfonate, we show the existence of a redox state associated with replication stress-induced senescence termed senescence-associated redox state (SA-redox state). SA-redox state is characterized by its reactivity with superoxide-sensing fluorescent probes such as dihydroethidine, lucigenin and mitosox and peroxynitrite or hydroxyl radical sensing probe hydroxyphenyl fluorescein (HPF) but not the hydrogen peroxide (H₂O₂) reactive fluorescent probe CM-H₂DCFDA. Measurement of GSH and GSSH also reveals that SA-redox state mitigates the level of total GSH rather than oxidizes GSH to GSSG. Moreover, supporting the role of superoxide (O₂^.-) in the SA-redox state, we show that incubation of senescent RPE1-hTERT cells with the O₂^.- scavenger, Tiron, decreases the reactivity of SA-redox state with the oxidants' reactive probes lucigenin and HPF while the H₂O₂ antioxidant N-acetyl cysteine has no effect. SA-redox state does not participate in the loss of proliferative capacity, G2/M cell cycle arrest or the increase in SA-β-Gal activity. However, SA-redox state is associated with the activation of NF-κB, dictates the profile of the Senescence Associated Secretory Phenotype, increases TFEB protein level, promotes geroconversion evidenced by increased phosphorylation of S6K and S6 proteins, and influences senescent cells response to senolysis. Furthermore, we provide evidence for crosstalk between SA redox state, p53 and p21. While p53 mitigates the establishment of SA-redox state, p21 is critical for the sustained reinforcement of the SA-redox state involved in geroconversion and resistance to senolysis.

Effects of Antioxidant Gene Overexpression on Stress Resistance and Malignization In Vitro and In Vivo: A Review

Reactive oxygen species (ROS) are normal products of a number of biochemical reactions and are important signaling molecules. However, at the same time, they are toxic to cells and have to be strictly regulated by their antioxidant systems. The etiology and pathogenesis of many diseases are associated with increased ROS levels, and many external stress factors directly or indirectly cause oxidative stress in cells. Within this context, the overexpression of genes encoding the proteins in antioxidant systems seems to have become a viable approach to decrease the oxidative stress caused by pathological conditions and to increase cellular stress resistance. However, such manipulations unavoidably lead to side effects, the most dangerous of which is an increased probability of healthy tissue malignization or increased tumor aggression. The aims of the present review were to collect and systematize the results of studies devoted to the effects resulting from the overexpression of antioxidant system genes on stress resistance and carcinogenesis in vitro and in vivo. In most cases, the overexpression of these genes was shown to increase cell and organism resistances to factors that induce oxidative and genotoxic stress but to also have different effects on cancer initiation and promotion. The last fact greatly limits perspectives of such manipulations in practice. The overexpression of GPX3 and SOD3 encoding secreted proteins seems to be the "safest" among the genes that can increase cell resistance to oxidative stress. High efficiency and safety potential can also be found for SOD2 overexpression in combinations with GPX1 or CAT and for similar combinations that lead to no significant changes in H₂O₂ levels. Accumulation, systematization, and the integral analysis of data on antioxidant gene overexpression effects can help to develop approaches for practical uses in biomedical and agricultural areas. Additionally, a number of factors such as genetic and functional context, cell and tissue type, differences in the function of transcripts of one and the same gene, regulatory interactions, and additional functions should be taken into account.

Meta analysis of bioactive compounds, miRNA, siRNA and cell death regulators as sensitizers to doxorubicin induced chemoresistance

Cancer has presented to be the most challenging disease, contributing to one in six mortalities worldwide. The current treatment regimen involves multiple rounds of chemotherapy administration, alone or in combination. The treatment has adverse effects including cardiomyopathy, hepatotoxicity, and nephrotoxicity. In addition, the development of resistance to chemo has been attributed to cancer relapse and low patient overall survivability. Multiple drug resistance development may be through numerous factors such as up-regulation of drug transporters, drug inactivation, alteration of drug targets and drug degradation. Doxorubicin is a widely used first line chemotherapeutic drug for a myriad of cancers. It has multiple intracellular targets, DNA intercalation, adduct formation, topoisomerase inhibition, iron chelation, reactive oxygen species generation and promotes immune mediated clearance of the tumor. Agents that can sensitize the resistant cancer cells to the chemotherapeutic drug are currently the focus to improve the clinical efficiency of cancer therapy. This review summarizes the recent 10-year research on the use of natural phytochemicals, inhibitors of apoptosis and autophagy, miRNAs, siRNAs and nanoformulations being investigated for doxorubicin chemosensitization.

Interplay between Mitochondrial Metabolism and Cellular Redox State Dictates Cancer Cell Survival

Mitochondria are the main powerhouse of the cell, generating ATP through the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS), which drives myriad cellular processes. In addition to their role in maintaining bioenergetic homeostasis, changes in mitochondrial metabolism, permeability, and morphology are critical in cell fate decisions and determination. Notably, mitochondrial respiration coupled with the passage of electrons through the electron transport chain (ETC) set up a potential source of reactive oxygen species (ROS). While low to moderate increase in intracellular ROS serves as secondary messenger, an overwhelming increase as a result of either increased production and/or deficient antioxidant defenses is detrimental to biomolecules, cells, and tissues. Since ROS and mitochondria both regulate cell fate, attention has been drawn to their involvement in the various processes of carcinogenesis. To that end, the link between a prooxidant milieu and cell survival and proliferation as well as a switch to mitochondrial OXPHOS associated with recalcitrant cancers provide testimony for the remarkable metabolic plasticity as an important hallmark of cancers. In this review, the regulation of cell redox status by mitochondrial metabolism and its implications for cancer cell fate will be discussed followed by the significance of mitochondria-targeted therapies for cancer.

Epigenetic derepression converts PPARγ into a druggable target in triple-negative and endocrine-resistant breast cancers

Clinical trials repurposing peroxisome proliferator-activated receptor-gamma (PPARγ) agonists as anticancer agents have exhibited lackluster efficacy across a variety of tumor types. Here, we report that increased PPARG expression is associated with a better prognosis but is anticorrelated with histone deacetylase (HDAC) 1 and 2 expressions. We show that HDAC overexpression blunts anti-proliferative and anti-angiogenic responses to PPARγ agonists via transcriptional and post-translational mechanisms, however, these can be neutralized with clinically approved and experimental HDAC inhibitors. Supporting this notion, concomitant treatment with HDAC inhibitors was required to license the tumor-suppressive effects of PPARγ agonists in triple-negative and endocrine-refractory breast cancer cells, and combination therapy also restrained angiogenesis in a tube formation assay. This combination was also synergistic in estrogen receptor-alpha (ERα)-positive cells because HDAC blockade abrogated ERα interference with PPARγ-regulated transcription. Following a pharmacokinetics optimization study, the combination of rosiglitazone and a potent pan-HDAC inhibitor, LBH589, stalled disease progression in a mouse model of triple-negative breast cancer greater than either of the monotherapies, while exhibiting a favorable safety profile. Our findings account for historical observations of de-novo resistance to PPARγ agonist monotherapy and propound a therapeutically cogent intervention against two aggressive breast cancer subtypes.

Inhibition of the NRF2/KEAP1 Axis: A Promising Therapeutic Strategy to Alter Redox Balance of Cancer Cells

Significance: The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) pathway is a crucial and highly conserved defensive system that is required to maintain or restore the intracellular homeostasis in response to oxidative, electrophilic, and other types of stress conditions. The tight control of NRF2 function is maintained by a complex network of biological interactions between positive and negative regulators that ultimately ensure context-specific activation, culminating in the NRF2-driven transcription of cytoprotective genes. Recent Advances: Recent studies indicate that deregulated NRF2 activation is a frequent event in malignant tumors, wherein it is associated with metabolic reprogramming, increased antioxidant capacity, chemoresistance, and poor clinical outcome. On the other hand, the growing interest in the modulation of the cancer cells' redox balance identified NRF2 as an ideal therapeutic target. Critical Issues: For this reason, many efforts have been made to identify potent and selective NRF2 inhibitors that might be used as single agents or adjuvants of anticancer drugs with redox disrupting properties. Despite the lack of specific NRF2 inhibitors still represents a major clinical hurdle, the researchers have exploited alternative strategies to disrupt NRF2 signaling at different levels of its biological activation. Future Directions: Given its dualistic role in tumor initiation and progression, the identification of the appropriate biological context of NRF2 activation and the specific clinicopathological features of patients cohorts wherein its inactivation is expected to have clinical benefits, will represent a major goal in the field of cancer research. In this review, we will briefly describe the structure and function of the NRF2/ KEAP1 system and some of the most promising NRF2 inhibitors, with a particular emphasis on natural compounds and drug repurposing. Antioxid. Redox Signal. 34, 1428-1483.

Variation of PPARG Expression in Chemotherapy-Sensitive Patients of Hypopharyngeal Squamous Cell Carcinoma

Our previous study showed that the upregulation of peroxisome proliferator-activated receptor gamma (PPARG) could promote chemosensitivity of hypopharyngeal squamous cell carcinoma (HSCC) in chemotherapeutic treatments. Here, we acquired two more independent expression data of PPARG to validate the expression levels of PPARG in chemotherapy-sensitive patients (CSP) and its individualized variations compared to chemotherapy-non-sensitive patients (CNSP). Our results showed that overall PPARG expression was mildly downregulated (log fold change = −0.55; p value = 0.42; overexpression in three CSPs and reduced expression in four CSPs), which was not consistent with previous results (log fold change = 0.50; p = 0.22; overexpression in nine CSPs and reduced expression in three CSPs). Both studies indicated that PPARG expression variation was significantly associated with the Tumor-Node-Metastasis (TNM) stage (p = 7.45e − 7 and 6.50e − 4, for the first and second studies, respectively), which was used as one of the predictors of chemosensitivity. The new dataset analysis revealed 51 genes with significant gene expression changes in CSPs (LFC > 1 or <-1; p value < 0.01), and two of them (TMEM45A and RBP1) demonstrated strong coexpression with PPARG (Pearson correlation coefficient > 0.6 or <-0.6). There were 21 significant genes in the data from the first study, with no significant association with PPARG and no overlap with the 51 genes revealed in this study. Our results support the connection between PPARG and chemosensitivity in HSCC tumor cells. However, significant PPARG variation exists in CSPs, which may be influenced by multiple factors, including the TNM stage.

NRF2 and PPAR-γ Pathways in Oligodendrocyte Progenitors: Focus on ROS Protection, Mitochondrial Biogenesis and Promotion of Cell Differentiation

An adequate protection from oxidative and inflammatory reactions, together with the promotion of oligodendrocyte progenitor (OP) differentiation, is needed to recover from myelin damage in demyelinating diseases. Mitochondria are targets of inflammatory and oxidative insults and are essential in oligodendrocyte differentiation. It is known that nuclear factor-erythroid 2-related factor/antioxidant responsive element (NRF2/ARE) and peroxisome proliferator-activated receptor gamma/PPAR-γ response element (PPAR-γ/PPRE) pathways control inflammation and overcome mitochondrial impairment. In this study, we analyzed the effects of activators of these pathways on mitochondrial features, protection from inflammatory/mitochondrial insults and cell differentiation in OP cultures, to depict the specificities and similarities of their actions. We used dimethyl-fumarate (DMF) and pioglitazone (pio) as agents activating NRF2 and PPAR-γ, respectively, and two synthetic hybrids acting differently on the NRF2/ARE pathway. Only DMF and compound 1 caused early effects on the mitochondria. Both DMF and pio induced mitochondrial biogenesis but different antioxidant repertoires. Moreover, pio induced OP differentiation more efficiently than DMF. Finally, DMF, pio and compound 1 protected from tumor necrosis factor-alpha (TNF-α) insult, with pio showing faster kinetics of action and compound 1 a higher activity than DMF. In conclusion, NRF2 and PPAR-γ by inducing partially overlapping pathways accomplish complementary functions aimed at the preservation of mitochondrial function, the defense against oxidative stress and the promotion of OP differentiation.

P-cadherin induces anoikis-resistance of matrix-detached breast cancer cells by promoting pentose phosphate pathway and decreasing oxidative stress

Successful metastatic spreading relies on cancer cells with stem-like properties, glycolytic metabolism and increased antioxidant protection, allowing them to escape anoikis and to survive in circulation. The expression of P-cadherin, a poor prognostic factor in breast cancer, is associated with hypoxic, glycolytic and acidosis biomarkers. In agreement, P-cadherin-enriched breast cancer cell populations presents a glycolytic and an acid-resistance phenotype. Our aim was to evaluate whether P-cadherin expression controls the glycolytic and oxidative phosphorylation fluxes of matrix-detached breast cancer cells, acting as an antioxidant and enhancing their survival in anchorage-independent conditions. By using matrix-detached breast cancer cells, we concluded that P-cadherin increases glucose-6-phosphate dehydrogenase expression, up-regulating the carbon flux through the pentose phosphate pathway, while inhibiting pyruvate oxidation to acetyl-coA via pyruvate dehydrogenase kinase-4 (PDK-4) activation. Accordingly, P-cadherin expression conferred increased sensitivity to dichloroacetate (DCA), a PDK inhibitor. P-cadherin expression also regulates oxidative stress in matrix-detached breast cancer cells, through the control of antioxidant systems, such as catalase and superoxide dismutases (SOD)1 and 2, providing these cells with an increased resistance to doxorubicin-induced anoikis. Importantly, this association was validated in primary invasive breast carcinomas, where an enrichment of SOD2 was found in P-cadherin-overexpressing breast carcinomas. In conclusion, we propose that P-cadherin up-regulates carbon flux through the pentose phosphate pathway and decreases oxidative stress in matrix-detached breast cancer cells. These metabolic remodeling and antioxidant roles of P-cadherin can promote the survival of breast cancer cells in circulation and in metastatic sites, being a possible player in breast cancer therapeutic resistance to pro-oxidant-based interventions.

Modulation of MnSOD and FoxM1 Is Involved in Invasion and EMT Suppression by Isovitexin in Hepatocellular Carcinoma Cells

Background

Manganese superoxide dismutase (MnSOD) induces FoxM1 expression, subsequently contributing to migration in several cancer cells. Isovitexin (ISOV) was recently found to downregulate MnSOD and FoxM1, decreasing stemness in hepatocellular carcinoma (HCC) stem-like cells (HCSLCs). The current study aimed to determine whether inhibition of migration, invasion and EMT in HCSLCs by ISOV results from MnSOD/FoxM1 signaling blockade and subsequent Twist1, Slug, ZEB1 and MMP-2 downregulation.

Materials and Methods

We examined the migratory and invasive capabilities and EMT phenotype in HCC cells and their HCSLCs, respectively, by wound-healing assay, transwell invasion assay and Western blot after treatment with non-cytotoxic concentrations of ISOV, and explored the mechanism by which ISOV affects migration, invasion and EMT by MnSOD or FoxM1 knockdown and/or overexpression in HCSLCs or HCC cells.

Results

The results showed that ISOV not only downregulated MnSOD and FoxM1 but also suppressed the migratory and invasive capabilities and reversed the EMT phenotype in HCSLCs, which was reflected by elevated E-cadherin protein amounts, and reduced N-cadherin, Twist1, Slug, ZEB1 and MMP-2 protein levels. The suppressive effects of ISOV on the migratory and invasive capabilities and EMT phenotype could be potentiated by MnSOD or FoxM1 knockdown in HCSLCs, and attenuated by MnSOD or FoxM1 overexpression in HCC cells. Importantly, FoxM1 overexpression reversed MnSOD knockdown combined with ISOV suppression on the migratory and invasive capabilities and EMT phenotype in HCSLCs, while having little effects on MnSOD expression.

Conclusion

Collectively, the above findings demonstrated that ISOV suppresses migration, invasion and EMT in HCSLCs by blocking MnSOD/FoxM1 signaling subsequently inhibiting the expression of EMT-related transcription factors and MMP-2.

Pparg may Promote Chemosensitivity of Hypopharyngeal Squamous Cell Carcinoma

The upregulation of peroxisome proliferator-activated receptor gamma (PPARG) has been shown to increase the chemosensitivity of several human cancers. This study is aimed at studying if PPARG sensitizes hypopharyngeal squamous cell carcinoma (HSCC) in chemotherapeutic treatments and at dissecting possible mechanisms of observed effects. We integrated large-scale literature data and HSCC gene expression data to identify regulatory pathways that link PPARG and chemosensitivity in HSCC. Expression levels of molecules within the PPARG regulatory pathways were compared in 21 patients that underwent chemotherapy for primary HSCC, including 12 chemotherapy-sensitive patients (CSP) and 9 chemotherapy-nonsensitive patients (CNSP). In the CPS group, expression levels of PPARG were higher than that in the CNSP group (log‐fold‐change = 0.50). Structured text mining identified two chemosensitivity-related regulatory pathways driven by PPARG. In the CSP group, expression levels for 7 chemosensitivity-promoting genes were increased, while for 13 chemosensitivity suppressing the gene expression levels were decreased. Our results support the chemosensitivity-promoting role of PPARG in HSCC tumor cells, most likely by affecting both cell proliferation and cell motility pathways.

Proapoptotic activity induced by photodynamic reaction with novel cyanine dyes in caspase-3-deficient human breast adenocarcinoma cell lines (MCF/WT and MCF/DX)

Photodynamic therapy (PDT) is currently one of the cancer treatment options. PDT requires the application of a photosensitizer (such as: porphyrins, chlorines, and phthalocyanines) that selectively targets malignant cells. It is a dilemma to find a proper photosensitizer. In our study, we have tested a new in-vitro group of cyanine dyes. These dyes are widely applied in biotechnology as fluorescent markers. Two malignant adenocarcinoma cell lines (MCF-7/WT and MCF-7/DOX) were investigated using photodynamic reaction (PDR) with four cyanine dyes (KF-570, HM-118, FBF-749, and ER-139). KF-570 and HM-118 were irradiated with red light (630 nm), whereas FBF-749 and ER-139 with green light (435 nm). To evaluate PDR efficiency, a clonogenic test was conducted. Apoptosis was investigated by TUNEL and NCA (neutral comet) assays. Proteins selected as indicators of the apoptotic pathway (AIF, sPLA2, Smac/Diablo) and intracellular response markers (SOD-1 and GST-pi) were detected using western blot. The highest number of apoptotic cells (ca. 100%) was observed after PDR with HM-118 and KF-570 in both conducted tests, in both cell lines. The results showed that HM-118 and KF-570 cyanine dyes demonstrated a major phototoxic effect causing apoptosis in doxorubicin-resistant and sensitive cell lines.

Impact of ROS Generated by Chemical, Physical, and Plasma Techniques on Cancer Attenuation

For the last few decades, while significant improvements have been achieved in cancer therapy, this family of diseases is still considered one of the deadliest threats to human health. Thus, there is an urgent need to find novel strategies in order to tackle this vital medical issue. One of the most pivotal causes of cancer initiation is the presence of reactive oxygen species (ROS) inside the body. Interestingly, on the other hand, high doses of ROS possess the capability to damage malignant cells. Moreover, several important intracellular mechanisms occur during the production of ROS. For these reasons, inducing ROS inside the biological system by utilizing external physical or chemical methods is a promising approach to inhibit the growth of cancer cells. Beside conventional technologies, cold atmospheric plasmas are now receiving much attention as an emerging therapeutic tool for cancer treatment due to their unique biophysical behavior, including the ability to generate considerable amounts of ROS. This review summarizes the important mechanisms of ROS generated by chemical, physical, and plasma approaches. We also emphasize the biological effects and cancer inhibition capabilities of ROS.

Isovitexin reduces carcinogenicity and stemness in hepatic carcinoma stem-like cells by modulating MnSOD and FoxM1

Background

Manganese superoxide dismutase (MnSOD) upregulating FoxM1 have previously been demonstrated promoting lung cancer stemness. Isovitexin exhibits antitumor activities in various cancers. This study aimed to assess whether isovitexin inhibits hepatic carcinoma stem-like cells (HCSLCs) features via regulating MnSOD and FoxM1 expression.

Methods

Second-generation spheres from the hepatic carcinoma cell lines, respectively, were used as HCSLCs. Protein amounts of MnSOD, FoxM1 and stemness-associated markers (CD133, CD44, ALDH1, Bmi1, Nanog and Oct4) were determined by immunoblotting. In vitro carcinogenicity was evaluated by sphere- and colony-formation assays. The effects of isovitexin on HCSLC carcinogenicity and stemness were examined in vitro and in xenograft models. An adenoviral delivery system was employed to manipulate MnSOD and/or FoxM1. Luciferase reporter assay was performed to verify isovitexin downregulated FoxM1 by inhibiting MnSOD-mediated effects of E2F1 and/or Sp1 on activation of FoxM1 promoter.

Results

FoxM1 upregulation by MnSOD contributed to carcinogenicity and stemness, with increased sphere- and colony-formation capabilities, upregulated stemness-associated markers and CD133⁺ subpopulation as well as elevated oncogenicity in vivo in HCSLCs compared with hepatic carcinoma cells. Isovitexin substantially decreased sphere and colony formation rates, and stemness-associated markers in cultured HCSLCs by suppressing MnSOD and FoxM1 expression. Importantly, isovitexin significantly inhibited tumor growth of in nude mice bearing HCSLCs and reduced CD133 protein expression of xenograft in nude mice. MnSOD or FoxM1 knockdown enhanced the effects of isovitexin suppression on carcinogenicity and stemness in HCSLC. MnSOD or FoxM1 overexpression attenuated the effects of isovitexin. Additionally, isovitexin and MnSOD knockdown could inhibit FoxM1 reporter activity via a decreased binding of E2F1 and/or Sp1 onto FoxM1 promoter. FoxM1 overexpression reversed the effects of isovitexin combined with MnSOD knockdown, without affecting MnSOD expression. Moreover, MnSOD knockdown plus thiostrepton, a FoxM1 specific inhibitor, cooperated with isovitexin to repress xenograft tumor growth and downregulate MnSOD and FoxM1 in nude mice bearing HCSLCs from MHCC97H cells.

Conclusions

Isovitexin inhibits carcinogenicity and stemness in HCSLCs by downregulating FoxM1via inhibition of MnSOD.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1244-6) contains supplementary material, which is available to authorized users.

Effect of Manganese Chloride and of Cotreatment with Cadmium Chloride on the In Vitro Proliferative, Motile and Invasive Behavior of MDA-MB231 Breast Cancer Cells

We examined the dose⁻response effect of MnCl₂ on the proliferative behavior of triple-negative breast cancer MDA-M231 cells vs. immortalized HB2 cells from breast epithelium taken as nontumoral counterparts. We also tested the effect of MnCl₂ on tumor cell invasiveness in vitro by evaluating the relative invasion indexes through Boyden chamber assays. Moreover, we checked whether cotreatment with both MnCl₂ and CdCl₂ could modify the observed biological response by MDA-MB231 cells. Our results show a promotional impact of MnCl₂ on cell proliferation, with 5 µM concentration inducing the more pronounced increase after 96-h exposure, which is not shared by HB2 cells. Exposure to 5 µM MnCl₂ induced also an elevation of the relative invasion index of cancer cells. The Mn-mediated stimulatory effects were counteracted by cotreatment with CdCl₂. These data support the concept that human exposure to high environmental concentrations of Mn may increase the risk of carcinogenesis and metastasis by prompting the expansion and dissemination of triple-negative breast cancer cells. On the other hand, the Mn-counteracting anticancer property of Cd looks promising and deserves a more detailed characterization of the involved intracellular targets aimed to the molecular modeling of specific antineoplastic agents against malignant breast cancer spreading.

MnSOD is implicated in accelerated wound healing upon Negative Pressure Wound Therapy (NPWT): A case in point for MnSOD mimetics as adjuvants for wound management

Negative Pressure Wound Therapy (NPWT), a widely used modality in the management of surgical and trauma wounds, offers clear benefits over conventional wound healing strategies. Despite the wide-ranging effects ascribed to NPWT, the precise molecular mechanisms underlying the accelerated healing supported by NPWT remains poorly understood. Notably, cellular redox status-a product of the balance between cellular reactive oxygen species (ROS) production and anti-oxidant defense systems-plays an important role in wound healing and dysregulation of redox homeostasis has a profound effect on wound healing. Here we investigated potential links between the use of NPWT and the regulation of antioxidant mechanisms. Using patient samples and a rodent model of acute injury, we observed a significant accumulation of MnSOD protein as well as higher enzymatic activity in tissues upon NPWT. As a proof of concept and to outline the important role of SOD activity in wound healing, we replaced NPWT by the topical application of a MnSOD mimetic, Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP5+, MnE, BMX-010, AEOl10113) in the rodent model. We observed that MnE is a potent wound healing enhancer as it appears to facilitate the formation of new tissue within the wound bed and consequently advances wound closure by two days, compared to the non-treated animals. Taken together, these results show for the first time a link between NPWT and regulation of antioxidant mechanism through the maintenance of MnSOD activity. Additionally this discovery outlined the potential role of MnSOD mimetics as topical agents enhancing wound healing.

Upregulation of FoxM1 by MnSOD Overexpression Contributes to Cancer Stem-Like Cell Characteristics in the Lung Cancer H460 Cell Line

Manganese superoxide dismutase promotes migration and invasion in lung cancer cells via upregulation of the transcription factor forkhead box M1. Here, we assessed whether upregulation of forkhead box M1 by manganese superoxide dismutase overexpression mediates the acquisition of cancer stem-like cell characteristics in non-small cell lung cancer H460 cells. The second-generation spheroids from H460 cells were used as lung cancer stem-like cells. The levels of manganese superoxide dismutase, forkhead box M1, stemness markers (CD133, CD44, and ALDH1), and transcription factors (Bmi1, Nanog, and Sox2) were analyzed by Western blot. Sphere formation in vitro and carcinogenicity of lung cancer stem-like cells were evaluated by spheroid formation assay and limited dilution xenograft assays. Knockdown or overexpression of manganese superoxide dismutase or/and forkhead box M1 by transduction with short hairpin RNA(shRNA) or complementary DNA were performed for mechanistic studies. We showed that manganese superoxide dismutase and forkhead box M1 amounts as well as the expression levels of stemness markers and transcription factors sphere formation in vitro, and carcinogenicity of lung cancer stem-like cells were higher than in monolayer cells. Lung cancer stem-like cells transduced with manganese superoxide dismutase shRNA or FoxM1 shRNA exhibited decreased sphere formation and lower amounts of stemness markers and transcription factors. Overexpression of manganese superoxide dismutase or FoxM1 in H460 cells resulted in elevated sphere formation rates and protein levels of stemness markers and transcription factors. Meanwhile, manganese superoxide dismutase knockdown or overexpression accordingly altered forkhead box M1 levels. However, forkhead box M1 knockdown or overexpression had no effect on manganese superoxide dismutase levels but inhibited or promoted lung cancer stem-like cell functions. Interestingly, forkhead box M1 overexpression alleviated the inhibitory effects of manganese superoxide dismutase knockdown in lung cancer stem-like cells. In a panel of non-small cell lung cancer cells, including H441, H1299, and H358 cells, compared to the respective monolayer counterparts, the expression levels of manganese superoxide dismutase and forkhead box M1 were elevated in the corresponding spheroids. These findings revealed the role of forkhead box M1 upregulation by manganese superoxide dismutase overexpression in maintaining lung cancer stem-like cell properties. Therefore, inhibition of forkhead box M1 upregulation by manganese superoxide dismutase overexpression may represent an effective therapeutic strategy for non-small cell lung cancer.

Mn Porphyrin-Based Redox-Active Drugs: Differential Effects as Cancer Therapeutics and Protectors of Normal Tissue Against Oxidative Injury

SIGNIFICANCE

After approximatelty three decades of research, two Mn(III) porphyrins (MnPs), MnTE-2-PyP⁵⁺ (BMX-010, AEOL10113) and MnTnBuOE-2-PyP⁵⁺ (BMX-001), have progressed to five clinical trials. In parallel, another similarly potent metal-based superoxide dismutase (SOD) mimic-Mn(II)pentaaza macrocycle, GC4419-has been tested in clinical trial on application, identical to that of MnTnBuOE-2-PyP⁵⁺-radioprotection of normal tissue in head and neck cancer patients. This clearly indicates that Mn complexes that target cellular redox environment have reached sufficient maturity for clinical applications. Recent Advances: While originally developed as SOD mimics, MnPs undergo intricate interactions with numerous redox-sensitive pathways, such as those involving nuclear factor κB (NF-κB) and nuclear factor E2-related factor 2 (Nrf2), thereby impacting cellular transcriptional activity. An increasing amount of data support the notion that MnP/H₂O₂/glutathione (GSH)-driven catalysis of S-glutathionylation of protein cysteine, associated with modification of protein function, is a major action of MnPs on molecular level.

CRITICAL ISSUES

Differential effects of MnPs on normal versus tumor cells/tissues, which support their translation into clinic, arise from differences in their accumulation and redox environment of such tissues. This in turn results in different yields of MnP-driven modifications of proteins. Thus far, direct evidence for such modification of NF-κB, mitogen-activated protein kinases (MAPK), phosphatases, Nrf2, and endogenous antioxidative defenses was provided in tumor, while indirect evidence shows the modification of NF-κB and Nrf2 translational activities by MnPs in normal tissue.

FUTURE DIRECTIONS

Studies that simultaneously explore differential effects in same animal are lacking, while they are essential for understanding of extremely intricate interactions of metal-based drugs with complex cellular networks of normal and cancer cells/tissues.

Reactive Oxygen Species and Oncoprotein Signaling-A Dangerous Liaison

SIGNIFICANCE

There is evidence to implicate reactive oxygen species (ROS) in tumorigenesis and its progression. This has been associated with the interplay between ROS and oncoproteins, resulting in enhanced cellular proliferation and survival. Recent Advances: To date, studies have investigated specific contributions of the crosstalk between ROS and signaling networks in cancer initiation and progression. These investigations have challenged the established dogma of ROS as agents of cell death by demonstrating a secondary function that fuels cell proliferation and survival. Studies have thus identified (onco)proteins (Bcl-2, STAT3/5, RAS, Rac1, and Myc) in manipulating ROS level as well as exploiting an altered redox environment to create a milieu conducive for cancer formation and progression.

CRITICAL ISSUES

Despite these advances, drug resistance and its association with an altered redox metabolism continue to pose a challenge at the mechanistic and clinical levels. Therefore, identifying specific signatures, altered protein expressions, and modifications as well as protein-protein interplay/function could not only enhance our understanding of the redox networks during cancer initiation and progression but will also provide novel targets for designing specific therapeutic strategies.

FUTURE DIRECTIONS

Not only a heightened realization is required to unravel various gene/protein networks associated with cancer formation and progression, particularly from the redox standpoint, but there is also a need for developing more sensitive tools for assessing cancer redox metabolism in clinical settings. This review attempts to summarize our current knowledge of the crosstalk between oncoproteins and ROS in promoting cancer cell survival and proliferation and treatment strategies employed against these oncoproteins. Antioxid. Redox Signal.

Clair WH, St. Clair DK. Redox Paradox: A Novel Approach to Therapeutics-Resistant Cancer

SIGNIFICANCE

Cancer cells that are resistant to radiation and chemotherapy are a major problem limiting the success of cancer therapy. Aggressive cancer cells depend on elevated intracellular levels of reactive oxygen species (ROS) to proliferate, self-renew, and metastasize. As a result, these aggressive cancers maintain high basal levels of ROS compared with normal cells. The prominence of the redox state in cancer cells led us to consider whether increasing the redox state to the condition of oxidative stress could be used as a successful adjuvant therapy for aggressive cancers. Recent Advances: Past attempts using antioxidant compounds to inhibit ROS levels in cancers as redox-based therapy have met with very limited success. However, recent clinical trials using pro-oxidant compounds reveal noteworthy results, which could have a significant impact on the development of strategies for redox-based therapies.

CRITICAL ISSUES

The major objective of this review is to discuss the role of the redox state in aggressive cancers and how to utilize the shift in redox state to improve cancer therapy. We also discuss the paradox of redox state parameters; that is, hydrogen peroxide (H2O2) as the driver molecule for cancer progression as well as a target for cancer treatment.

FUTURE DIRECTIONS

Based on the biological significance of the redox state, we postulate that this system could potentially be used to create a new avenue for targeted therapy, including the potential to incorporate personalized redox therapy for cancer treatment.

Evaluation and prognostic significance of manganese superoxide dismutase in clear cell renal cell carcinoma

The antioxidant enzyme manganese superoxide dismutase (MnSOD) is up-regulated in renal cell carcinoma (RCC) and has been implicated in multiple stages of RCC tumorigenesis and progression. However, the prognostic significance of MnSOD in RCC has not been fully elucidated. This study aimed to investigate the expression profile of MnSOD in clear cell RCC (ccRCC) tissues and evaluate the clinical significance of this enzyme in ccRCC patients. MnSOD mRNA was assessed in 42 ccRCC and 33 normal kidney tissues using the Oncomine database, and its protein was detected in 145 ccRCCs and 3 normal tissues by immunohistochemistry staining. The Oncomine database confirmed higher MnSOD mRNA expression in ccRCC than in normal tissues, and immunohistochemistry analysis revealed that MnSOD protein expression was inversely associated with pathologic grade, clinical stage, tumor size, M status, and cancer-specific survival. In addition, univariate survival analysis demonstrated that high-grade, late-stage, large tumors, stage M₁, and low MnSOD expression were associated with a poorer prognosis for cancer-specific survival, and further multivariate analysis revealed that tumor grade, stage, M₁ stage, and MnSOD were identified as independent prognostic factors for cancer-specific survival in patients with ccRCC. Collectively, these findings imply that MnSOD is a promising prognostic marker in ccRCC and implies that oxidative stress might be involved in the tumorigenesis and progression of ccRCC.

PPARγ Ligand-induced Annexin A1 Expression Determines Chemotherapy Response via Deubiquitination of Death Domain Kinase RIP in Triple-negative Breast Cancers

Metastatic breast cancer is still incurable so far; new specifically targeted and more effective therapies for triple-negative breast cancer (TNBC) are required in the clinic. In this study, our clinical data have established that basal and claudin-low subtypes of breast cancer (TNBC types) express significantly higher levels of Annexin A1 (ANXA1) with poor survival outcomes. Using human cancer cell lines that model the TNBC subtype, we observed a strong positive correlation between expression of ANXA1 and PPARγ. A similar correlation between these two markers was also established in our clinical breast cancer patients' specimens. To establish a link between these two markers in TNBC, we show de novo expression of ANXA1 is induced by activation of PPARγ both in vitro and in vivo and it has a predictive value in determining chemosensitivity to PPARγ ligands. Mechanistically, we show for the first time PPARγ-induced ANXA1 protein directly interacts with receptor interacting protein-1 (RIP1), promoting its deubiquitination and thereby activating the caspase-8-dependent death pathway. We further identified this underlying mechanism also involved a PPARγ-induced ANXA1-dependent autoubiquitination of cIAP1, the direct E3 ligase of RIP1, shifting cIAP1 toward proteosomal degradation. Collectively, our study provides first insight for the suitability of using drug-induced expression of ANXA1 as a new player in RIP1-induced death machinery in TNBCs, presenting itself both as an inclusion criterion for patient selection and surrogate marker for drug response in future PPARγ chemotherapy trials. Mol Cancer Ther; 16(11); 2528-42. ©2017 AACR.

PGC1α induced by reactive oxygen species contributes to chemoresistance of ovarian cancer cells

Malignant cells are subjected to high levels of oxidative stress that arise from the increased production of reactive oxygen species (ROS) due to their altered metabolism. They activate antioxidant mechanisms to relieve the oxidative stress, and thereby acquire resistance to chemotherapeutic agents. In the present study, we found that PGC1α, a key molecule that both increases mitochondrial biogenesis and activates antioxidant enzymes, enhances chemoresistance in response to ROS generated by exposure of cells to ovarian sphere-forming culture conditions. Cells in the cultured spheres exhibited stem cell-like characteristics, and maintained higher ROS levels than their parent cells. Intriguingly, scavenging ROS diminished the aldehyde dehydrogenase (ALDH)-positive cell population, and inhibited proliferation of the spheres. ROS production triggered PGC1α expression, which in turn caused changes to mitochondrial biogenesis and activity within the spheres. The drug-resistant phenotype was observed in both spheres and PGC1α-overexpressing parent cells, and conversely, PGC1α knockdown sensitized the spheres to cisplatin treatment. Similarly, floating malignant cells derived from patient ascitic fluid included an ALDH-positive population and exhibited the tendency of a positive correlation between expressions of multidrug resistance protein 1 (MDR1) and PGC1α. The present study suggests that ROS-induced PGC1α mediates chemoresistance, and represents a novel therapeutic target to overcome chemoresistance in ovarian cancer.

LC-MS/MS Analysis Unravels Deep Oxidation of Manganese Superoxide Dismutase in Kidney Cancer

Manganese superoxide dismutase (MNSOD) is one of the major scavengers of reactive oxygen species (ROS) in mitochondria with pivotal regulatory role in ischemic disorders, inflammation and cancer. Here we report oxidative modification of MNSOD in human renal cell carcinoma (RCC) by the shotgun method using data-dependent liquid chromatography tandem mass spectrometry (LC-MS/MS). While 5816 and 5571 proteins were identified in cancer and adjacent tissues, respectively, 208 proteins were found to be up- or down-regulated (p < 0.05). Ontological category, interaction network and Western blotting suggested a close correlation between RCC-mediated proteins and oxidoreductases such as MNSOD. Markedly, oxidative modifications of MNSOD were identified at histidine (H⁵⁴ and H⁵⁵), tyrosine (Y⁵⁸), tryptophan (W¹⁴⁷, W¹⁴⁹, W²⁰⁵ and W²¹⁰) and asparagine (N²⁰⁶ and N²⁰⁹) residues additional to methionine. These oxidative insults were located at three hotspots near the hydrophobic pocket of the manganese binding site, of which the oxidation of Y⁵⁸, W¹⁴⁷ and W¹⁴⁹ was up-regulated around three folds and the oxidation of H⁵⁴ and H⁵⁵ was detected in the cancer tissues only (p < 0.05). When normalized to MNSOD expression levels, relative MNSOD enzymatic activity was decreased in cancer tissues, suggesting impairment of MNSOD enzymatic activity in kidney cancer due to modifications. Thus, LC-MS/MS analysis revealed multiple oxidative modifications of MNSOD at different amino acid residues that might mediate the regulation of the superoxide radicals, mitochondrial ROS scavenging and MNSOD activity in kidney cancer.

TIP60 inhibits metastasis by ablating DNMT1-SNAIL2-driven epithelial-mesenchymal transition program

HIV-Tat-interacting protein of 60 kDa (TIP60) is a lysine acetyltransferase and known to be downregulated in multiple cancers. Among various signalling pathways, TIP60 is implicated in regulating epithelial-mesenchymal transition (EMT). Here, we show that TIP60 expression abrogates cell migration and metastatic potential of breast cancer cells using in vitro and in vivo models. Mechanistically, we show that this is through its ability to destabilize DNMT1 and inhibit SNAIL2 function (SNAIL2-mediated EMT/cell migration). Depletion of TIP60 stabilizes DNMT1 and increases SNAIL2 levels, resulting in EMT. Recruitment of DNMT1 to the SNAIL2 targets in the absence of TIP60 increases DNA methylation on their promoter region and further represses the expression of epithelial markers. In pathophysiological scenario, we find TIP60 to be significantly downregulated in breast cancer patients with poor overall survival and disease-free survival prognoses. These data suggest that levels of TIP60 can be a prognostic marker of breast cancer progression and stabilization of TIP60 could be a promising strategy to treat cancers.

Breast Cancer: A Molecular and Redox Snapshot

SIGNIFICANCE

Breast cancer is a unique disease characterized by heterogeneous cell populations causing roadblocks in therapeutic medicine, owing to its complex etiology and primeval understanding of the biology behind its genesis, progression, and sustenance. Globocan statistics indicate over 1.7 million new breast cancer diagnoses in 2012, accounting for 25% of all cancer morbidities.

RECENT ADVANCES

Despite these dismal statistics, the introduction of molecular gene signature platforms, progressive therapeutic approaches in diagnosis, and management of breast cancer has led to more effective treatment strategies and control measures concurrent with an equally reassuring decline in the mortality rate.

CRITICAL ISSUES

However, an enormous body of research in this area is requisite as high mortality associated with metastatic and/or drug refractory tumors continues to present a therapeutic challenge. Despite advances in systemic chemotherapy, the median survival of patients harboring metastatic breast cancers continues to be below 2 years.

FUTURE DIRECTIONS

Hence, a massive effort to scrutinize and evaluate chemotherapeutics on the basis of the molecular classification of these cancers is undertaken with the objective to devise more attractive and feasible approaches to treat breast cancers and improve patients' quality of life. This review aims to summarize the current understanding of the biology of breast cancer as well as challenges faced in combating breast cancer, with special emphasis on the current battery of treatment strategies. We will also try and gain perspective from recent encounters on novel findings responsible for the progression and metastatic transformation of breast cancer cells in an endeavor to develop more targeted treatment options. Antioxid. Redox Signal. 25, 337-370.

Manganese Superoxide Dismutase Expression Regulates the Switch Between an Epithelial and a Mesenchymal-Like Phenotype in Breast Carcinoma

AIM

Epithelial-mesenchymal transition (EMT) is characterized by the acquisition of invasive fibroblast-like morphology by epithelial cells that are highly polarized. EMT is recognized as a crucial mechanism in cancer progression and metastasis. In this study, we sought to assess the involvement of manganese superoxide dismutase (MnSOD) during the switch between epithelial-like and mesenchymal-like phenotypes in breast carcinoma.

RESULTS

Analysis of breast carcinomas from The Cancer Genome Atlas database revealed strong positive correlation between tumors' EMT score and the expression of MnSOD. This positive correlation between MnSOD and EMT score was significant and consistent across all breast cancer subtypes. Similarly, a positive correlation of EMT score and MnSOD expression was observed in established cell lines derived from breast cancers exhibiting phenotypes ranging from the most epithelial to the most mesenchymal. Interestingly, using phenotypically distinct breast cancer cell lines, we provide evidence that constitutively high or induced expression of MnSOD promotes the EMT-like phenotype by way of a redox milieu predominantly driven by hydrogen peroxide (H2O2). Conversely, gene knockdown of MnSOD results in the reversal of EMT to a mesenchymal-epithelial transition (MET)-like program, which appears to be a function of superoxide (O2(-•))-directed signaling.

INNOVATION AND CONCLUSION

These data underscore the involvement of MnSOD in regulating the switch between the EMT and MET-associated phenotype by influencing cellular redox environment via its effect on the intracellular ratio between O2(-•) and H2O2. Strategies to manipulate MnSOD expression and/or the cellular redox milieu vis-a-vis O2(-•):H2O2 could have potential therapeutic implications. Antioxid. Redox Signal. 25, 283-299.

Synthetic Lethality of a Novel Small Molecule Against Mutant KRAS-Expressing Cancer Cells Involves AKT-Dependent ROS Production

AIMS

We recently reported the death-inducing activity of a small-molecule compound, C1, which triggered reactive oxygen species (ROS)-dependent autophagy-associated apoptosis in a variety of human cancer cell lines. In this study, we examine the ability of the compound to specifically target cancer cells harboring mutant KRAS with minimal activity against wild-type (WT) RAS-expressing cells.

RESULTS

HCT116 cells expressing mutated KRAS are susceptible, while the WT-expressing HT29 cells are resistant. Interestingly, C1 triggers activation of mutant RAS, which results in the downstream phosphorylation and activation of AKT/PKB. Gene knockdown of KRAS or AKT or their pharmacological inhibition resulted in the abrogation of C1-induced ROS production and rescued tumor colony-forming ability. We also made use of HCT116 mutant KRAS knockout (KO) cells, which express only a single WT KRAS allele. Exposure of KO cells to C1 failed to increase mitochondrial ROS and cell death, unlike the parental cells harboring mutant KRAS. Similarly, mutant KRAS-transformed prostate epithelial cells (RWPE-1-RAS) were more sensitive to the ROS-producing and death-inducing effects of C1 than the vector only expressing RWPE-1 cells. An in vivo model of xenograft tumors generated with HCT116 KRAS(WT/MUT) or KRAS(WT/-) cells showed the efficacy of C1 treatment and its ability to affect the relative mitotic index in tumors harboring KRAS mutant.

INNOVATION AND CONCLUSION

These data indicate a synthetic lethal effect against cells carrying mutant KRAS, which could have therapeutic implications given the paucity of KRAS-specific chemotherapeutic strategies. Antioxid. Redox Signal. 24, 781-794.

Role of nuclear receptors in breast cancer stem cells

The recapitulation of primary tumour heterogenity and the existence of a minor sub-population of cancer cells, capable of initiating tumour growth in xenografts on serial passages, led to the hypothesis that cancer stem cells (CSCs) exist. CSCs are present in many tumours, among which is breast cancer. Breast CSCs (BCSCs) are likely to sustain the growth of the primary tumour mass, as well as to be responsible for disease relapse and metastatic spreading. Consequently, BCSCs represent the most significant target for new drugs in breast cancer therapy. Both the hypoxic condition in BCSCs biology and pro-inflammatory cytokine network has gained increasing importance in the recent past. Breast stromal cells are crucial components of the tumours milieu and are a major source of inflammatory mediators. Recently, the anti-inflammatory role of some nuclear receptors ligands has emerged in several diseases, including breast cancer. Therefore, the use of nuclear receptors ligands may be a valid strategy to inhibit BCSCs viability and consequently breast cancer growth and disease relapse.

A central role for TRPS1 in the control of cell cycle and cancer development

The eukaryotic cell cycle is controlled by a complex regulatory network, which is still poorly understood. Here we demonstrate that TRPS1, an atypical GATA factor, modulates cell proliferation and controls cell cycle progression. Silencing TRPS1 had a differential effect on the expression of nine key cell cycle-related genes. Eight of these genes are known to be involved in the regulation of the G2 phase and the G2/M transition of the cell cycle. Using cell synchronization studies, we confirmed that TRPS1 plays an important role in the control of cells in these phases of the cell cycle. We also show that silencing TRPS1 controls the expression of 53BP1, but not TP53. TRPS1 silencing also decreases the expression of two histone deacetylases, HDAC2 and HDAC4, as well as the overall HDAC activity in the cells, and leads to the subsequent increase in the acetylation of histone4 K16 but not of histone3 K9 or K18. Finally, we demonstrate that TRPS1 expression is elevated in luminal breast cancer cells and luminal breast cancer tissues as compared with other breast cancer subtypes. Overall, our study proposes that TRPS1 acts as a central hub in the control of cell cycle and proliferation during cancer development.