Analysis of Zinc-Exporters Expression in Prostate Cancer

Distinctive expression and cellular localisation of zinc homeostasis-related proteins in breast and prostate cancer cells

BACKGROUND

Zinc transport proteins (ZIP and ZnT), metallothioneins (MT) and protein kinase CK2 are involved in dysregulation of zinc homeostasis in breast and prostate cancer cells. Following up our previous research, we targeted ZIP12, ZnT1, MT2A and CK2 in this study by investigating their expression levels and protein localisation.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunofluorescence confocal microscopy were employed to quantify the expression of ZIP12, ZnT1, MT2A and CK2 subunits in a panel of breast and prostate cell lines without or with extracellular zinc exposure. The cellular localisations of these target proteins were also examined by immunofluorescence confocal microscopy.

RESULTS

In response to the extracellular zinc exposure, the gene expression was elevated for SLC39A12 (ZIP12), SLC30A1 (ZnT1) and MT2A (MT2A) in normal prostate epithelial cells (RWPE-1) in contrast to their cancerous counterparts (PC3 and DU145), whilst the gene expression was higher for SLC39A12 (ZIP12) and SLC30A1 (ZnT1) in both normal (MCF10A) and basal breast cancer cells (MDA-MB-231) compared to luminal breast cancer cells (MCF-7). At the protein level, the expression for both ZIP12 and ZnT1 was trending lower in the time course for the breast cancer cells whilst their expression was remained constant in the normal breast epithelial cells. The expression of ZIP12 in prostate cancer cells was higher than the normal prostate cells. The protein expression for CK2 α/αꞌ and CK2β was markedly higher in prostate cancer cells than the normal prostate cells. Upon extracellular zinc exposure, ZIP12 was, for the first time, conspicuously localised in the plasma membrane of breast cancer cells but not in normal breast epithelial cells and prostate cells. ZnT1 is only localised in the plasma membrane of breast cancer cells. MT2A is distinctively seen close to the plasma membrane in breast cancer cells. CK2 is also for the first time shown to be localised in proximity to the plasma membrane of breast cancer cells.

CONCLUSION

The findings, particularly the localisation of ZIP12 and CK2, are novel and significant for our understanding of zinc homeostasis in breast and prostate cancer cells.

Integrated pan-cancer genomic analysis reveals the role of SLC30A5 in the proliferation, metastasis, and prognosis of hepatocellular carcinoma

Background: SLC30A5, a member of the solute transporter protein family, is implicated in tumorigenesis and cancer progression. This study aimed to explore the expression and prognostic significance of SLC30A family genes in pan-cancer, with a specific emphasis on SLC30A5 in hepatocellular carcinoma (HCC). Methods: Expression patterns and prognostic implications of SLC30A family genes were assessed across 33 cancer types, especially HCC. Co-expression analysis explored the relationship between SLC30A5 and immune cell infiltration, immune checkpoints, pathway molecules related to tumor angiogenesis and epithelial-mesenchymal transition (EMT). The role of SLC30A5 in HCC was evaluated through in vitro and in vivo assays, including CCK8 viability assay, EdU cell proliferation assay, colony formation assay, apoptosis assay, wound healing assay, transwell migration assay, and xenograft mouse model assay using Huh7 cells with targeted knockdown of SLC30A5. Results: SLC30A family genes exhibited overexpression in various tumors. In HCC, upregulation of SLC30A5 expression correlated with adverse prognosis. Significant associations were observed between SLC30A5 expression and immune cell infiltration, immune checkpoints, molecules involved in angiogenesis, and EMT. SLC30A5 overexpression was associated with advanced disease stages, higher histological grades, and vascular invasion. Single-cell RNA sequencing data (GSE112271) revealed notable SLC30A5 expression in malignant cells. In vitro and in vivo assays demonstrated that SLC30A5 knockdown in Huh7 cells reduced proliferation, migration, and invasion while promoting apoptosis. Conclusions: This study highlights the clinical relevance of SLC30A5 in HCC, emphasizing its role in cell proliferation and migration. SLC30A5 emerges as a promising candidate for a prognostic marker and a potential target in HCC.

Emerging Perspectives in Zinc Transporter Research in Prostate Cancer: An Updated Review

Dysregulation of zinc and zinc transporters families has been associated with the genesis and progression of prostate cancer. The prostate epithelium utilizes two types of zinc transporters, the ZIP (Zrt-, Irt-related Protein) and the ZnTs (Zinc Transporter), to transport zinc from the blood plasma to the gland lumen. ZIP transporters uptake zinc from extracellular space and organelle lumen, while ZnT transporters release zinc outside the cells or to organelle lumen. In prostate cancer, a commonly observed low zinc concentration in prostate tissue has been correlated with downregulations of certain ZIPs (e.g., ZIP1, ZIP2, ZIP3, ZIP14) and upregulations of specific ZnTs (e.g., ZnT1, ZnT9, ZnT10). These alterations may enable cancer cells to adapt to toxic high zinc levels. While zinc supplementation has been suggested as a potential therapy for this type of cancer, studies have yielded inconsistent results because some trials have indicated that zinc supplementation could exacerbate cancer risk. The reason for this discrepancy remains unclear, but given the high molecular and genetic variability present in prostate tumors, it is plausible that some zinc transporters-comprising 14 ZIP and 10 ZnT members-could be dysregulated in others patterns that promote cancer. From this perspective, this review highlights novel dysregulation, such as ZIP-Up/ZnT-Down, observed in prostate cancer cell lines for ZIP4, ZIP8, ZnT2, ZnT4, ZnT5, etc. Additionally, an in silico analysis of an available microarray from mouse models of prostate cancer (Nkx3.1;Pten) predicts similar dysregulation pattern for ZIP4, ZIP8, and ZnT2, which appear in early stages of prostate cancer progression. Furthermore, similar dysregulation patterns are supported by an in silico analysis of RNA-seq data from human cancer tumors available in cBioPortal. We discuss how these dysregulations of zinc transporters could impact zinc supplementation trials, particularly focusing on how the ZIP-Up/ZnT-Down dysregulation through various mechanisms might promote prostate cancer progression.

Structural insights into the calcium-coupled zinc export of human ZnT1

Cellular zinc (Zn2+) homeostasis is essential to human health and is under tight regulations. Human zinc transporter 1 (hZnT1) is a plasma membrane-localized Zn2+ exporter belonging to the ZnT family, and its functional aberration is associated with multiple diseases. Here, we show that hZnT1 works as a Zn2+/Ca2+ exchanger. We determine the structure of hZnT1 using cryo-electron microscopy (cryo-EM) single particle analysis. hZnT1 adopts a homodimeric structure, and each subunit contains a transmembrane domain consisting of six transmembrane segments, a cytosolic domain, and an extracellular domain. The transmembrane region displays an outward-facing conformation. On the basis of structural and functional analysis, we propose a model for the hZnT1-mediated Zn2+/Ca2+ exchange. Together, these results facilitate our understanding of the biological functions of hZnT1 and provide a basis for further investigations of the ZnT family transporters.

High intratumoral plasma cells content in primary prostate cancer defines a subset of tumors with potential susceptibility to immune-based treatments

BACKGROUND

Data on advanced prostate cancer (PCa) suggest more prior systemic therapies might reduce tumor immune responsiveness. In treatment-naïve primary PCa, recent work correlated intratumoral plasma cell content with enhanced tumor immune-responsiveness. We sought to identify features of localized PCa at a high risk of recurrence following local treatment with high plasma cell content to help focus future immune-based neoadjuvant trials.

METHODS

We performed retrospective analyses of molecular profiles from three independent cohorts of over 1300 prostate tumors. We used Wilcoxon Rank Sum to compare molecular pathways between tumors with high and low intratumoral plasma cell content and multivariable Cox proportional hazards regression analyses to assess metastasis-free survival.

RESULTS

We validated an expression-based signature for intratumoral plasma cell content in 113 primary prostate tumors with both RNA-expression data and digital image quantification of CD138+ cells (plasma cell marker) based on immunohistochemisty. The signature showed castration-resistant tumors (n = 101) with more prior systemic therapies contained lower plasma cell content. In high-grade primary PCa, tumors with high plasma cell content were associated with increased predicted response to immunotherapy and decreased response to androgen-deprivation therapy. Master regulator analyses identified upregulated transcription factors implicated in immune (e.g. SKAP1, IL-16, and HCLS1), and B-cell activity (e.g. VAV1, SP140, and FLI-1) in plasma cell-high tumors. Master regulators overactivated in tumors with low plasma cell content were associated with shorter metastasis-free survival following radical prostatectomy.

CONCLUSIONS

Markers of plasma cell activity might be leveraged to augment clinical trial targeting and selection and better understand the potential for immune-based treatments in patients with PCa at a high risk of recurrence following local treatment.

Zinc in Prostate Health and Disease: A Mini Review

Introduction-With the high global prevalence of prostate cancer and associated mortalities, it is important to enhance current clinical practices for better prostate cancer outcomes. The current review is towards understanding the value of Zn towards this mission. Method-General information on Zn in biology and multiple aspects of Zn involvement in prostate health and disease were referred to in PubMed. Results-The most influential feature of Zn towards prostate health is its ability to retain sufficient citrate levels for a healthy prostate. Zn deficiencies were recorded in serum, hair, and prostate tissue of men with prostate cancer compared to non-cancer controls. Zn gut absorption, albumin binding, and storage compete with various factors. There are multiple associations of Zn cellular influx and efflux transporters, Zn finger proteins, matrix metalloproteinases, and Zn signaling with prostate cancer outcomes. Such Zn marker variations associated with prostate cancer recorded from biological matrices may improve algorithms for prostate cancer screening, prognosis, and management when coupled with standard clinical practices. Discussion-The influence of Zn in prostatic health and disease is multidimensional, therefore more personalized Zn requirements may be beneficial. Several opportunities exist to utilize and improve understanding of Zn associations with prostate health and disease.

Impact of Zinc Transport Mechanisms on Embryonic and Brain Development

The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.

Expression profiles of the genes associated with zinc homeostasis in normal and cancerous breast and prostate cells

Zn2+ dyshomeostasis is an intriguing phenomenon in breast and prostate cancers, with breast cancer cells exhibiting higher intracellular Zn2+ level compared to their corresponding normal epithelial cells, in contrast to the low Zn2+ level in prostate cancer cells. In order to gain molecular insights into the zinc homeostasis of breast and prostate cancer cells, this study profiled the expression of 28 genes, including 14 zinc importer genes (SLC39A1-14) which encode ZIP1-14 to transport Zn2+ into the cytoplasm, 10 zinc exporter genes (SLC30A1-10) which encode ZnT1-10 to transport Zn2+ out of the cytoplasm and 4 metallothionein genes (MT1B, MT1F, MT1X, MT2A) in breast (MCF10A, MCF-7, MDA-MB-231) and prostate (RWPE-1, PC3, DU145) cell lines in response to extracellular zinc exposures at a mild cytotoxic dosage and a benign dosage. The RNA samples were prepared at 0 min (T0), 30 min (T30) and 120 min (T120) in a time course with or without zinc exposure, which were used for profiling the baseline and dynamic gene expression. The up-regulation of MT genes was observed across the breast and prostate cancer cell lines. The expression landscape of SLC39A and SLC30A was revealed by the qRT-PCR data of this study, which sheds light on the divergence of intracellular Zn2+ levels for breast and prostate cancer cells. Taken together, the findings are valuable in unravelling the molecular intricacy of zinc homeostasis in breast and prostate cancer cells.

PLK4 is upregulated in prostate cancer and its inhibition reduces centrosome amplification and causes senescence

BACKGROUND

Identification of novel molecular target(s) is important for designing newer mechanistically driven approaches for the treatment of prostate cancer (PCa), which is one of the main causes of morbidity and mortality in men. In this study, we determined the role of polo-like kinase 4 (PLK4), which regulates centriole duplication and centrosome amplification (CA), in PCa.

MATERIALS AND METHODS

Employing human PCa tissue microarrays, we assessed the prevalence of CA, correlated with Gleason score, and estimated major causes of CA in PCa (cell doubling vs. centriole overduplication) by staining for mother/mature centrioles. We also assessed PLK4 expression and correlated it with CA in human PCa tissues and cell lines. Further, we determined the effects of PLK4 inhibition in human PCa cells.

RESULTS

Compared to benign prostate, human PCa demonstrated significantly higher CA, which was also positively correlated with the Gleason score. Further, most cases of CA were found to arise by centriole overduplication rather than cell doubling events (e.g., cytokinesis failure) in PCa. In addition, PLK4 was overexpressed in human PCa cell lines and tumors. Moreover, PLK4 inhibitors CFI-400945 and centrinone-B inhibited cell growth, viability, and colony formation of both androgen-responsive and androgen-independent PCa cell lines. PLK4 inhibition also induced cell cycle arrest and senescence in human PCa cells.

CONCLUSIONS

CA is prevalent in PCa and arises predominantly by centriole overduplication as opposed to cell doubling events. Loss of centrioles is cellular stress that can promote senescence and suggests that PLK4 inhibition may be a viable therapeutic strategy in PCa.

The Role of the Metabolism of Zinc and Manganese Ions in Human Cancerogenesis

Metal ion homeostasis is fundamental for life. Specifically, transition metals iron, manganese and zinc play a pivotal role in mitochondrial metabolism and energy generation, anti-oxidation defense, transcriptional regulation and the immune response. The misregulation of expression or mutations in ion carriers and the corresponding changes in Mn²⁺ and Zn²⁺ levels suggest that these ions play a pivotal role in cancer progression. Moreover, coordinated changes in Mn²⁺ and Zn²⁺ ion carriers have been detected, suggesting that particular mechanisms influenced by both ions might be required for the growth of cancer cells, metastasis and immune evasion. Here, we present a review of zinc and manganese pathophysiology suggesting that these ions might cooperatively regulate cancerogenesis. Zn and Mn effects converge on mitochondria-induced apoptosis, transcriptional regulation and the cGAS-STING signaling pathway, mediating the immune response. Both Zn and Mn influence cancer progression and impact treatment efficacy in animal models and clinical trials. We predict that novel strategies targeting the regulation of both Zn and Mn in cancer will complement current therapeutic strategies.

Stage-specific differential expression of zinc transporter SLC30A and SLC39A family proteins during prostate tumorigenesis

Prostate cancer (PCa) initiation and progression uniquely modify the prostate milieu to aid unrestrained cell proliferation. One salient modification is the loss of the ability of prostate epithelial cells to accumulate high concentrations of zinc; however, molecular alterations associated with loss of zinc accumulating capability in malignant prostate cells remain poorly understood. Herein, we assessed the stage-specific expression of zinc transporters (ZNTs) belonging to the ZNT (SLC30A) and Zrt- and Irt-like protein (ZIP) (SLC39A) solute-carrier family in the prostate tissues of different genetically engineered mouse models (GEMM) of PCa (TMPRSS2-ERG.Pten^flox/flox , Hi-Myc^{+/ -} , and transgenic adenocarcinoma of mouse prostate), their age-matched wild-type controls, and 104 prostate core biopsies from human patients with different pathological lesions. Employing immunohistochemistry, differences in the levels of protein expression and spatial distribution of ZNT were evaluated as a function of the tumor stage. Results indicated that the expression of zinc importers (ZIP1, ZIP2, and ZIP3), which function to sequester zinc from circulation and prostatic fluid, was low to negligible in the membranes of the malignant prostate cells in both GEMM and human prostate tissues. Regarding zinc exporters (ZNT1, ZNT2, ZNT9, and ZNT10) that export excess zinc into the extracellular spaces or intracellular organelles, their expression was low in normal prostate glands of mice and humans; however, it was significantly upregulated in prostate adenocarcinoma lesions in GEMM and PCa patients. Together, our findings provide new insights into altered expression of ZNTs during the progression of PCa and indicate that changes in zinc homeostasis could possibly be an early-initiation event during prostate tumorigenesis and a likely prevention/intervention target.

Golgi Metal Ion Homeostasis in Human Health and Diseases

The Golgi apparatus is a membrane organelle located in the center of the protein processing and trafficking pathway. It consists of sub-compartments with distinct biochemical compositions and functions. Main functions of the Golgi, including membrane trafficking, protein glycosylation, and sorting, require a well-maintained stable microenvironment in the sub-compartments of the Golgi, along with metal ion homeostasis. Metal ions, such as Ca²⁺, Mn²⁺, Zn²⁺, and Cu²⁺, are important cofactors of many Golgi resident glycosylation enzymes. The homeostasis of metal ions in the secretory pathway, which is required for proper function and stress response of the Golgi, is tightly regulated and maintained by transporters. Mutations in the transporters cause human diseases. Here we provide a review specifically focusing on the transporters that maintain Golgi metal ion homeostasis under physiological conditions and their alterations in diseases.

A pair of transporters controls mitochondrial Zn2+ levels to maintain mitochondrial homeostasis

Zn²⁺ is required for the activity of many mitochondrial proteins, which regulate mitochondrial dynamics, apoptosis and mitophagy. However, it is not understood how the proper mitochondrial Zn²⁺ level is achieved to maintain mitochondrial homeostasis. Using Caenorhabditis elegans, we reveal here that a pair of mitochondrion-localized transporters controls the mitochondrial level of Zn²⁺. We demonstrate that SLC-30A9/ZnT9 is a mitochondrial Zn²⁺ exporter. Loss of SLC-30A9 leads to mitochondrial Zn²⁺ accumulation, which damages mitochondria, impairs animal development and shortens the life span. We further identify SLC-25A25/SCaMC-2 as an important regulator of mitochondrial Zn²⁺ import. Loss of SLC-25A25 suppresses the abnormal mitochondrial Zn²⁺ accumulation and defective mitochondrial structure and functions caused by loss of SLC-30A9. Moreover, we reveal that the endoplasmic reticulum contains the Zn²⁺ pool from which mitochondrial Zn²⁺ is imported. These findings establish the molecular basis for controlling the correct mitochondrial Zn²⁺ levels for normal mitochondrial structure and functions.

Are trace element concentrations suitable biomarkers for the diagnosis of cancer?

Despite advances in cancer research, cancer is still one of the leading causes of death worldwide. An early diagnosis substantially increases the survival rate and treatment success. Thus, it is important to establish biomarkers which could reliably identify cancer patients. As cancer is associated with changes in the systemic trace element status and distribution, serum concentrations of selenium, iron, copper, and zinc could contribute to an early diagnosis. To test this hypothesis, case control studies measuring trace elements in cancer patients vs. matched controls were selected and discussed focusing on lung, prostate, breast, and colorectal cancer. Overall, cancer patients had elevated serum copper and diminished zinc levels, while selenium and iron did not show consistent changes for all four cancer types. Within the tumor tissue, mainly copper and selenium are accumulating. Whether these concentrations also predict the survival probability of cancer patients needs to be further investigated.

Dietary Phytochemicals in Zinc Homeostasis: A Strategy for Prostate Cancer Management

Studies have suggested an important role of the trace element zinc (Zn) in prostate biology and functions. Zn has been shown to exist in very high concentrations in the healthy prostate and is important for several prostatic functions. In prostate cancer (PCa), Zn levels are significantly decreased and inversely correlated with disease progression. Ideally, restoration of adequate Zn levels in premalignant/malignant prostate cells could abort prostate malignancy. However, studies have shown that Zn supplementation is not an efficient way to significantly increase Zn concentrations in PCa. Based on a limited number of investigations, the reason for the lower levels of Zn in PCa is believed to be the dysregulation of Zn transporters (especially ZIP and ZnT family of proteins), metallothioneins (for storing and releasing Zn), and their regulators (e.g., Zn finger transcription factor RREB1). Interestingly, the level of Zn in cells has been shown to be modulated by naturally occurring dietary phytochemicals. In this review, we discussed the effect of selected phytochemicals (quercetin, resveratrol, epigallocatechin-3-gallate and curcumin) on Zn functioning and proposes that Zn in combination with specific dietary phytochemicals may lead to enhanced Zn bioaccumulation in the prostate, and therefore, may inhibit PCa.

Analysis of the Differences in the Expression of mRNAs and miRNAs Associated with Drug Resistance in Endometrial Cancer Cells Treated with Salinomycin

Background:

It is important to understand the molecular mechanisms involved in cancer drug resistance and to study the activity of new drugs, e.g. salinomycin.

Objective:

The purpose of the study was to analyze changes in the expression of genes associated with drug resistance in the Ishikawa endometrial cancer cell line when treated with salinomycin. In addition, changes in the level of miRNA potentially regulating these mRNAs were evaluated.

Materials and Methods:

Endometrial cancer cells were treated with 1 μM of salinomycin for 12, 24 and 48 hours periods. Untreated cells were a control culture. The molecular analysis consists of mRNA and miRNA microarray analysis and the RTqPCR technique.

Results:

The following was observed about the number of mRNAs differentiating the cell culture exposed to the drug compared to a control culture: H-12 vs. C - 9 mRNAs, H_24 vs. C - 6 mRNAs, and H_48 vs. C - 1 mRNA. It was noted that 4 of the 9 differentiating mRNAs were characteristic for 12 hours of exposure to salinomycin and they correspond to the following genes: TUFT1, ABCB1, MTMR11, and MX2. After 24 hours, 2 mRNAs were characteristic for this time of incubation cells with salinomycin: TUFT1 and MYD88 and after 48 hours, SLC30A5 could also be observed.

Discussion:

The highest differences in expression were indicated for TUFT1, MTMR11, and SLC30A5. The highest influence probability was determined between TUFT1 and hsa- miR-3188 (FC + 2.48), MTMR11and has-miR-16 (FC -1.74), and between SLC30A5 and hsa-miR-30d (FC -2.01).

Conclusions:

Salinomycin induces changes in the activity of mRNA and miRNA participating in drug resistance; however, the observed changes in character are the expected result of anti-cancer treatment.

Epigenetic targeting of SLC30A3 by HDAC1 is related to the malignant phenotype of glioblastoma

The epigenetic abnormality is believed as a major driver for cancer initiation. Histone modification plays a vital role in tumor formation and progression. Particularly, alteration in histone acetylation has been highly associated with gene expression, cell cycle, as well as carcinogenesis. By analyzing glioblastoma (GBM)-related microarray from the GEO database and conducting chromatin immunoprecipitation-sequencing (ChIP-seq), we discovered that solute carrier family 30 member 3 (SLC30A3), a super enhancer (SE)-regulated factor, was significantly reduced in GBM tissues. Furthermore, histone deacetylase 1 (HDAC1), overexpressed in GBM tissues, could inhibit SLC30A3 expression by promoting histone H3K27ac deacetylation modification of the SE region of SLC30A3. Our functional validation revealed that SLC30A3 can inhibit the growth and metastatic spread of GBM cells in vitro and in vivo, and can activate the MAPK signaling pathway to promote apoptosis of GBM cells. Moreover, overexpression of HDAC1 resulted in a significant increase in DNA replication activity, a significant decline in apoptosis and cell cycle arrest in GBM cells. In a word, these findings indicate that combined epigenetic targeting of SLC30A3 by HDAC1 and SE is potentially therapeutically feasible in GBM.

Transmembrane 163 (TMEM163) Protein: A New Member of the Zinc Efflux Transporter Family

A growing body of evidence continues to demonstrate the vital roles that zinc and its transporters play on human health. The mammalian solute carrier 30 (SLC30) family, with ten current members, controls zinc efflux transport in cells. TMEM163, a recently reported zinc transporter, has similar characteristics in both predicted transmembrane domain structure and function to the cation diffusion facilitator (CDF) protein superfamily. This review discusses past and present data indicating that TMEM163 is a zinc binding protein that transports zinc in cells. We provide a brief background on TMEM163’s discovery, transport feature, protein interactome, and similarities, as well as differences, with known SLC30 (ZnT) protein family. We also examine recent reports that implicate TMEM163 directly or indirectly in various human diseases such as Parkinson’s disease, Mucolipidosis type IV and diabetes. Overall, the role of TMEM163 protein in zinc metabolism is beginning to be realized, and based on current evidence, we propose that it is likely a new CDF member belonging to mammalian SLC30 (ZnT) zinc efflux transporter proteins.

Comprehensive analysis of the expression of SLC30A family genes and prognosis in human gastric cancer

The solute carrier 30 (SLC30) family genes play a fundamental role in various cancers. However, the diverse expression patterns, prognostic value, and potential mechanism of SLC30A family genes in gastric cancer (GC) remain unknown. Herein, we analyzed the expression and survival data of SLC30A family genes in GC patients using multiple bioinformatic approaches. Expression data of SLC30A family genes for GC patients were extracted from the Cancer Genome Atlas (TCGA) and genetic alteration frequency assessed by using cBioportal database. And validated the expression of SLC30A family genes in GC tissues and corresponding normal tissues. The prognostic value of SLC30A family genes in gastric cancer patients were explored using Kaplan–Meier plotter database. Functional enrichment analysis performed using DAVID database and clusterProfiler package. And ssGSEA algorithm was performed to explore the relationship between the SLC30A family genes and the infiltration of immune cells. We found that the median expression levels of SLC30A1-3, 5–7, and 9 were significantly upregulated in gastric cancer tissues compared to non-cancerous tissues, while SLC30A4 was downregulated. Meanwhile, SLC30A1-7, and 9 were significantly correlated with advanced tumor stage and nodal metastasis status, SLC30A5-7, and 9–10 were significantly related to the Helicobacter pylori infection status of GC patients. High expression of five genes (SLC30A1, 5–7, and 9) was significantly correlated with better overall survival (OS), first progression survival (FPS), and post progression survival (PPS). Conversely, upregulated SLC30A2-4, 8, and 10 expression was markedly associated with poor OS, FP and PPS. And SLC30A family genes were closely associated with the infiltration of immune cells. The present study implied that SLC30A5 and 7 may be potential biomarkers for predicting prognosis in GC patients, SLC30A2 and 3 play an oncogenic role in GC patients and could provide a new strategy for GC patients treatment.

The ZIP6/ZIP10 heteromer is essential for the zinc-mediated trigger of mitosis

Zinc has been known to be essential for cell division for over 40 years but the molecular pathways involved remain elusive. Cellular zinc import across biological membranes necessitates the help of zinc transporters such as the SLC39A family of ZIP transporters. We have discovered a molecular process that explains why zinc is required for cell division, involving two highly regulated zinc transporters, as a heteromer of ZIP6 and ZIP10, providing the means of cellular zinc entry at a specific time of the cell cycle that initiates a pathway resulting in the onset of mitosis. Crucially, when the zinc influx across this heteromer is blocked by ZIP6 or ZIP10 specific antibodies, there is no evidence of mitosis, confirming the requirement for zinc influx as a trigger of mitosis. The zinc that influxes into cells to trigger mitosis additionally changes the phosphorylation state of STAT3 converting it from a transcription factor to a protein that complexes with this heteromer and pS³⁸Stathmin, the form allowing microtubule rearrangement as required in mitosis. This discovery now explains the specific cellular role of ZIP6 and ZIP10 and how they have special importance in the mitosis process compared to other ZIP transporter family members. This finding offers new therapeutic opportunities for inhibition of cell division in the many proliferative diseases that exist, such as cancer.

Recapitulation of prostate tissue cell type-specific transcriptomes by an in vivo primary prostate tissue xenograft model

Studies of the normal functions and diseases of the prostate request in vivo models that maintain the tissue architecture and the multiple-cell type compartments of human origin in order to recapitulate reliably the interactions of different cell types. Cell type-specific transcriptomes are critical to reveal the roles of each cell type in the functions and diseases of the prostate. A primary prostate tissue xenograft model was developed using fresh human prostate tissue specimens transplanted onto male mice that were castrated surgically and implanted with a device to maintain circulating testosterone levels comparable to adult human males. Endothelial cells and epithelial cells were isolated from 7 fresh human prostate tissue specimens and from primary tissue xenografts established from 9 fresh human prostate tissue specimens, using antibody-conjugated magnetic beads specific to human CD31 and human EpCAM, respectively. Transcriptomes of endothelial, epithelial and stromal cell fractions were obtained using RNA-Seq. Global and function-specific gene expression profiles were compared in inter-cell type and inter-tissue type manners. Gene expression profiles in the individual cell types isolated from xenografts were similar to those of cells isolated from fresh tissue, demonstrating the value of the primary tissue xenograft model for studies of the inter-relationships between prostatic cell types and the role of such inter-relationships in organ development, disease progression, and response to drug treatments.

Detecting Prognosis Risk Biomarkers for Colon Cancer Through Multi-Omics-Based Prognostic Analysis and Target Regulation Simulation Modeling

Background

Colon cancer is one of the most common health threats for humans since its high morbidity and mortality. Detecting potential prognosis risk biomarkers (PRBs) is essential for the improvement of therapeutic strategies and drug development. Currently, although an integrated prognostic analysis of multi-omics for colon cancer is insufficient, it has been reported to be valuable for improving PRBs’ detection in other cancer types.

Aim

This study aims to detect potential PRBs for colon adenocarcinoma (COAD) samples through the cancer genome atlas (TCGA) by integrating muti-omics.

Materials and Methods

The multi-omics-based prognostic analysis (MPA) model was first constructed to systemically analyze the prognosis of colon cancer based on four-omics data of gene expression, exon expression, DNA methylation and somatic mutations on COAD samples. Then, the essential features related to prognosis were functionally annotated through protein–protein interaction (PPI) network and cancer-related pathways. Moreover, the significance of those essential prognostic features were further confirmed by the target regulation simulation (TRS) model. Finally, an independent testing dataset, as well as the single cell-based expression dataset were utilized to validate the generality and repeatability of PRBs detected in this study.

Results

By integrating the result of MPA modeling, as well the PPI network, integrated pathway and TRS modeling, essential features with gene symbols such as EPB41, PSMA1, FGFR3, MRAS, LEP, C7orf46, LOC285000, LBP, ZNF35, SLC30A3, LECT2, RNF7, and DYNC1I1 were identified as PRBs which provide high potential as drug targets for COAD treatment. Validation on the independent testing dataset demonstrated that these PRBs could be applied to distinguish the prognosis of COAD patients. Moreover, the prognosis of patients with different clinical conditions could also be distinguished by the above PRBs.

Conclusions

The MPA and TRS models constructed in this paper, as well as the PPI network and integrated pathway analysis, could not only help detect PRBs as potential therapeutic targets for COAD patients but also make it a paradigm for the prognostic analysis of other cancers.

Recent aspects of the effects of zinc on human health

Zinc (Zn) is one of the most important essential nutrients of great public health significance. It is involved in numerous biological functions and it is considered as a multipurpose trace element, due to its capacity to bind to more than 300 enzymes and more than 2000 transcriptional factors. Its role in biochemical pathways and cellular functions, such as the response to oxidative stress, homeostasis, immune responses, DNA replication, DNA damage repair, cell cycle progression, apoptosis and aging is significant. Zn is required for the synthesis of protein and collagen, thus contributing to wound healing and a healthy skin. Metallothioneins are metal-binding proteins and they are potent scavengers of heavy metals, including Zn, and protect the organism against stress. Zn deficiency is observed almost in 17% of the global population and affects many organ systems, leading to dysfunction of both humoral and cell-mediated immunity, thus increasing the susceptibility to infection. This review gives a thorough insight into the most recent evidence on the association between Zn biochemistry and human pathologies, epigenetic processes, gut microbial composition, drug targets and nanomedicine.

Growth Modulatory Role of Zinc in Prostate Cancer and Application to Cancer Therapeutics

Zinc is a group IIB heavy metal. It is an important regulator of major cell signaling pathways in most mammalian cells, functions as an antioxidant and plays a role in maintaining genomic stability. Zinc deficiency leads to severe diseases in the brain, pancreas, liver, kidneys and reproductive organs. Zinc loss occurs during tumor development in a variety of cancers. The prostate normally contains abundant intracellular zinc and zinc loss is a hallmark of the development of prostate cancer development. The underlying mechanism of this loss is not clearly understood. The knowledge that excess zinc prevents the growth of prostate cancers suggests that zinc-mediated therapeutics could be an effective approach for cancer prevention and treatment, although challenges remain. This review summarizes the specific roles of zinc in several cancer types focusing on prostate cancer. The relationship between prostate cancer and the dysregulation of zinc homeostasis is examined in detail in an effort to understand the role of zinc in prostate cancer.

Advances of Zinc Signaling Studies in Prostate Cancer

Prostate cancer (PCa) is one of the most common cancers and the second leading cause of cancer-related death among men worldwide. Despite progresses in early diagnosis and therapeutic strategies, prognosis for patients with advanced PCa remains poor. Noteworthily, a unique feature of healthy prostate is its highest level of zinc content among all soft tissues in the human body, which dramatically decreases during prostate tumorigenesis. To date, several reviews have suggested antitumor activities of zinc and its potential as a therapeutic strategy of PCa. However, an overview about the role of zinc and its signaling in PCa is needed. Here, we review literature related to the content, biological function, compounds and clinical application of zinc in PCa. We first summarize zinc content in prostate tissue and sera of PCa patients with their clinical relevance. We then elaborate biological functions of zinc signaling in PCa on three main aspects, including cell proliferation, death and tumor metastasis. Finally, we discuss clinical applications of zinc-containing compounds and proteins involved in PCa signaling pathways. Based on currently available studies, we conclude that zinc plays a tumor suppressive role and can serve as a biomarker in PCa diagnosis and therapies.

Alterations in ZnT1 expression and function lead to impaired intracellular zinc homeostasis in cancer

Zinc is vital for the structure and function of ~3000 human proteins and hence plays key physiological roles. Consequently, impaired zinc homeostasis is associated with various human diseases including cancer. Intracellular zinc levels are tightly regulated by two families of zinc transporters: ZIPs and ZnTs; ZIPs import zinc into the cytosol from the extracellular milieu, or from the lumen of organelles into the cytoplasm. In contrast, the vast majority of ZnTs compartmentalize zinc within organelles, whereas the ubiquitously expressed ZnT1 is the sole zinc exporter. Herein, we explored the hypothesis that qualitative and quantitative alterations in ZnT1 activity impair cellular zinc homeostasis in cancer. Towards this end, we first used bioinformatics to analyze inactivating mutations in ZIPs and ZNTs, catalogued in the COSMIC and gnomAD databases, representing tumor specimens and healthy population controls, respectively. ZnT1, ZnT10, ZIP8, and ZIP10 showed extremely high rates of loss of function mutations in cancer as compared to healthy controls. Analysis of the putative functional impact of missense mutations in ZnT1-ZnT10 and ZIP1-ZIP14, using homologous protein alignment and structural predictions, revealed that ZnT1 displays a markedly increased frequency of predicted functionally deleterious mutations in malignant tumors, as compared to a healthy population. Furthermore, examination of ZnT1 expression in 30 cancer types in the TCGA database revealed five tumor types with significant ZnT1 overexpression, which predicted dismal prognosis for cancer patient survival. Novel functional zinc transport assays, which allowed for the indirect measurement of cytosolic zinc levels, established that wild type ZnT1 overexpression results in low intracellular zinc levels. In contrast, overexpression of predicted deleterious ZnT1 missense mutations did not reduce intracellular zinc levels, validating eight missense mutations as loss of function (LoF) mutations. Thus, alterations in ZnT1 expression and LoF mutations in ZnT1 provide a molecular mechanism for impaired zinc homeostasis in cancer formation and/or progression.

OMICfpp: a fuzzy approach for paired RNA-Seq counts

BACKGROUND

RNA sequencing is a widely used technology for differential expression analysis. However, the RNA-Seq do not provide accurate absolute measurements and the results can be different for each pipeline used. The major problem in statistical analysis of RNA-Seq and in the omics data in general, is the small sample size with respect to the large number of variables. In addition, experimental design must be taken into account and few tools consider it.

RESULTS

We propose OMICfpp, a method for the statistical analysis of RNA-Seq paired design data. First, we obtain a p-value for each case-control pair using a binomial test. These p-values are aggregated using an ordered weighted average (OWA) with a given orness previously chosen. The aggregated p-value from the original data is compared with the aggregated p-value obtained using the same method applied to random pairs. These new pairs are generated using between-pairs and complete randomization distributions. This randomization p-value is used as a raw p-value to test the differential expression of each gene. The OMICfpp method is evaluated using public data sets of 68 sample pairs from patients with colorectal cancer. We validate our results through bibliographic search of the reported genes and using simulated data set. Furthermore, we compared our results with those obtained by the methods edgeR and DESeq2 for paired samples. Finally, we propose new target genes to validate these as gene expression signatures in colorectal cancer. OMICfpp is available at http://www.uv.es/ayala/software/OMICfpp_0.2.tar.gz .

CONCLUSIONS

Our study shows that OMICfpp is an accurate method for differential expression analysis in RNA-Seq data with paired design. In addition, we propose the use of randomized p-values pattern graphic as a powerful and robust method to select the target genes for experimental validation.

ARv7 Represses Tumor-Suppressor Genes in Castration-Resistant Prostate Cancer

Androgen deprivation therapy for prostate cancer (PCa) benefits patients with early disease, but becomes ineffective as PCa progresses to a castration-resistant state (CRPC). Initially CRPC remains dependent on androgen receptor (AR) signaling, often through increased expression of full-length AR (ARfl) or expression of dominantly active splice variants such as ARv7. We show in ARv7-dependent CRPC models that ARv7 binds together with ARfl to repress transcription of a set of growth-suppressive genes. Expression of the ARv7-repressed targets and ARv7 protein expression are negatively correlated and predicts for outcome in PCa patients. Our results provide insights into the role of ARv7 in CRPC and define a set of potential biomarkers for tumors dependent on ARv7.

A Brief Overview from the Physiological and Detrimental Roles of Zinc Homeostasis via Zinc Transporters in the Heart

Zinc (mostly as free/labile Zn²⁺) is an essential structural constituent of many proteins, including enzymes in cellular signaling pathways via functioning as an important signaling molecule in mammalian cells. In cardiomyocytes at resting condition, intracellular labile Zn²⁺ concentration ([Zn²⁺]_i) is in the nanomolar range, whereas it can increase dramatically under pathological conditions, including hyperglycemia, but the mechanisms that affect its subcellular redistribution is not clear. Therefore, overall, very little is known about the precise mechanisms controlling the intracellular distribution of labile Zn²⁺, particularly via Zn²⁺ transporters during cardiac function under both physiological and pathophysiological conditions. Literature data demonstrated that [Zn²⁺]_i homeostasis in mammalian cells is primarily coordinated by Zn²⁺ transporters classified as ZnTs (SLC30A) and ZIPs (SLC39A). To identify the molecular mechanisms of diverse functions of labile Zn²⁺ in the heart, the recent studies focused on the discovery of subcellular localization of these Zn²⁺ transporters in parallel to the discovery of novel physiological functions of [Zn²⁺]_i in cardiomyocytes. The present review summarizes the current understanding of the role of [Zn²⁺]_i changes in cardiomyocytes under pathological conditions, and under high [Zn²⁺]_i and how Zn²⁺ transporters are important for its subcellular redistribution. The emerging importance and the promise of some Zn²⁺ transporters for targeted cardiac therapy against pathological stimuli are also provided. Taken together, the review clearly outlines cellular control of cytosolic Zn²⁺ signaling by Zn²⁺ transporters, the role of Zn²⁺ transporters in heart function under hyperglycemia, the role of Zn²⁺ under increased oxidative stress and ER stress, and their roles in cancer are discussed.

Human-like hyperplastic prostate with low ZIP1 induced solely by Zn deficiency in rats

Prostate cancer is a leading cause of cancer death in men over 50 years of age, and there is a characteristic marked decrease in Zn content in the malignant prostate cells. The cause and consequences of this loss have thus far been unknown. We found that in middle-aged rats a Zn-deficient diet reduces prostatic Zn levels (P = 0.025), increases cellular proliferation, and induces an inflammatory phenotype with COX-2 overexpression. This hyperplastic/inflammatory prostate has a human prostate cancer-like microRNA profile, with up-regulation of the Zn-homeostasis-regulating miR-183-96-182 cluster (fold change = 1.41-2.38; P = 0.029-0.0003) and down-regulation of the Zn importer ZIP1 (target of miR-182), leading to a reduction of prostatic Zn. This inverse relationship between miR-182 and ZIP1 also occurs in human prostate cancer tissue, which is known for Zn loss. The discovery that the Zn-depleted middle-aged rat prostate has a metabolic phenotype resembling that of human prostate cancer, with a 10-fold down-regulation of citric acid (P = 0.0003), links citrate reduction directly to prostatic Zn loss, providing the underlying mechanism linking dietary Zn deficiency with miR-183-96-182 overexpression, ZIP1 down-regulation, prostatic Zn loss, and the resultant citrate down-regulation, changes mimicking features of human prostate cancer. Thus, dietary Zn deficiency during rat middle age produces changes that mimic those of human prostate carcinoma and may increase the risk for prostate cancer, supporting the need for assessment of Zn supplementation in its prevention.

The emerging role of zinc transporters in cellular homeostasis and cancer

Zinc is an essential micronutrient that plays a role in the structural or enzymatic functions of many cellular proteins. Cellular zinc homeostasis involves the opposing action of two families of metal transporters: the ZnT (SLC30) family that functions to reduce cytoplasmic zinc concentrations and the ZIP (SLC39) family that functions to increase cytoplasmic zinc concentrations. Fluctuations in intracellular zinc levels mediated by these transporter families affect signaling pathways involved in normal cell development, growth, differentiation and death. Consequently, changes in zinc transporter localization and function resulting in zinc dyshomeostasis have pathophysiological effects. Zinc dyshomeostasis has been implicated in the progression of cancer. Here we review recent progress toward understanding the structural basis for zinc transport by ZnT and ZIP family proteins, as well as highlight the roles of zinc as a signaling molecule in physiological conditions and in various cancers. As zinc is emerging as an important signaling molecule in the development and progression of cancer, the ZnT and ZIP transporters that regulate cellular zinc homeostasis are promising candidates for targeted cancer therapy.