Solute carriers as potential oncodrivers or suppressors: their key functions in malignant tumor formation

Paclitaxel-resistance facilitates glycolytic metabolism via Hexokinase-2-regulated ABC and SLC transporter genes in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) frequently develops resistance to platinum-based therapies, which is regarded as an aggressive subtype. However, metabolic changes in paclitaxel resistance remain unclear. Herein, we present the metabolic alternations of paclitaxel resistance in bioenergetic profiling in OCCC. Paclitaxel-resistant OCCC cells were developed and metabolically active with oxygen consumption rates (OCR) compared to parental cells. Metabolite profiling analysis revealed that paclitaxel-resistant OCCC cells reduced intracellular ATP and GTP influx rates, increasing the NADH/NAD+ ratio. We further demonstrated that paclitaxel-resistant OCCC cells led to characteristic alternations of metabolite levels in energy-requiring and energy-releasing steps of glycolysis and their corresponding glycolytic enzymes. Copy number alterations and RNA sequencing analysis demonstrated that ATP-binding cassette (ABC) transporters and solute carrier (SLC) transporter genes involved in glycolysis metabolism and molecular transport were enriched in paclitaxel-resistant OCCC cells. We first identified that Hexokinase 2 (HK2) expression is upregulated in paclitaxel-resistant OCCC cells to determine the quantity of glucose entering glycolysis. Utilizing proteolysis-targeting chimera (PROTAC) HK2 degraders, we also found that paclitaxel sensitivity, viability, and oxygen consumption rates under paclitaxel treatment were restored by HK2 degraders treatment, and decreased downstream expression of the ABC and SLC transporters was shown in OCCC cells. Taken together, these findings highlight the paclitaxel resistance in OCCC elucidates metabolic alternation, including ABC- and SLC- drug transporters, thereby affecting glycolysis metabolism in response to paclitaxel resistance, and HK2 may become a novel potential therapeutic target for paclitaxel resistance.

Targeting PNPO to suppress tumor growth via inhibiting autophagic flux and to reverse paclitaxel resistance in ovarian cancer

Our previous study showed that pyridoxine 5'-phosphate oxidase (PNPO) is a tissue biomarker of ovarian cancer (OC) and has a prognostic implication but detailed mechanisms remain unclear. The current study focused on PNPO-regulated lysosome/autophagy-mediated cellular processes and the potential role of PNPO in chemoresistance. We found that PNPO was overexpressed in OC cells and was a prognostic factor in OC patients. PNPO significantly promoted cell proliferation via the regulation of cyclin B1 and phosphorylated CDK1 and shortened the G2M phase in a cell cycle. Overexpressed PNPO enhanced the biogenesis and perinuclear distribution of lysosomes, promoting the degradation of autophagosomes and boosting the autophagic flux. Further, an autolysosome marker LAMP2 was upregulated in OC cells. Silencing LAMP2 suppressed cell growth and induced cell apoptosis. LAMP2-siRNA blocked PNPO action in OC cells, indicating that the function of PNPO on cellular processes was mediated by LAMP2. These data suggest the existence of the PNPO-LAMP2 axis. Moreover, silencing PNPO suppressed xenographic tumor formation. Chloroquine counteracted the promotion effect of PNPO on autophagic flux and inhibited OC cell survival, facilitating the inhibitory effect of PNPO-shRNA on tumor growth in vivo. Finally, PNPO was overexpressed in paclitaxel-resistant OC cells. PNPO-siRNA enhanced paclitaxel sensitivity in vitro and in vivo. In conclusion, PNPO has a regulatory effect on lysosomal biogenesis that in turn promotes autophagic flux, leading to OC cell proliferation, and tumor formation, and is a paclitaxel-resistant factor. These data imply a potential application by targeting PNPO to suppress tumor growth and reverse PTX resistance in OC.

Regulatory Effects of SLC7A2-CPB2 on Lymphangiogenesis: A New Approach to Suppress Lymphatic Metastasis in HNSCC

BACKGROUND

Lymph node metastasis (LNM) is a critical factor affecting the outcomes of head and neck squamous cell carcinoma (HNSCC) and the main reason for treatment failure. This study was designed to examine the effects of the key genes involved in the LNM of HNSCC.

METHODS

Tissue samples (HNSCC) were examined by transcriptome sequencing, and the core genes associated with LNM were detected via bioinformatics analysis. The functions of these core genes were then validated using the TCGA biological database and their effects on the propagation, invasion, and metastasis of HNSCC cells were evaluated through cell culture experiments. Moreover, the effect of core gene expression on the LNM capability of HNSCC was confirmed via a footpad xenograft mice model.

RESULTS

In the findings, a key gene involved in the LNM of HNSCC was identified as SLC7A2. It was correlated with adverse clinical prognosis and expressed with low expression in HNSCC tissues. As shown in cell culture experiments, FaDu and SCC15 cell growth, invasion, and migration were inhibited when SLC7A2 was overexpressed. Further, cell apoptosis was stimulated, and lymphangiogenesis was suppressed through the downregulation of CPB2 expression. Animal studies demonstrated that the growth and LNM of HNSCC cells were inhibited by SLC7A2 overexpression.

CONCLUSION

It is concluded that SLC7A2 is involved in HNSCC lymphatic metastasis by controlling CPB2 function. The results are anticipated to offer new directions for the effective treatment of HNSCC.

Exploring the prognostic landscape of oral squamous cell carcinoma through mitochondrial damage-related genes

Oral squamous cell carcinoma (OSCC), the most prevalent form of oral cancer, poses significant challenges to the medical community due to its high recurrence rate and low survival rate. Mitochondrial Damage-Related Genes (MDGs) have been closely associated with the occurrence, metastasis, and progression of OSCC. Consequently, we constructed a prognostic model for OSCC based on MDGs and identified potential mitochondrial damage-related biomarkers. Gene expression profiles and relevant clinical information were obtained from The Cancer Genome Atlas (TCGA) database. Differential analysis was conducted to identify MDGs associated with OSCC. COX analysis was employed to screen seven prognosis-related MDGs and build a prognostic prediction model for OSCC. Cases were categorized into low-risk or high-risk groups based on the optimal risk score threshold. Kaplan-Meier (KM) analysis revealed significant survival differences (P < 0.05). Additionally, the area under the ROC curve (AUC) for patient survival at 1 year, 3 years, and 5 years were 0.687, 0.704, and 0.70, respectively, indicating a high long-term predictive accuracy of the prognostic model. To enhance predictive accuracy, age, gender, risk score, and TN staging were incorporated into a nomogram and verified using calibration curves. Risk scoring based on MDGs was identified as a potential independent prognostic biomarker. Furthermore, BID and SLC25A20 were identified as two potential independent mitochondrial damage-related prognostic biomarkers, offering new therapeutic targets for OSCC.

SLC38A3 Promotes the Proliferation and Migration of Tumor Cells and Predicts Poor Prognosis in Colorectal Cancer

Previous studies have revealed that abnormal expressions of membrane transporters were associated with colorectal cancer (CRC). We herein performed a comprehensive bioinformatics analysis to identify the key transporter protein-related genes involved in CRC and potential mechanisms. Differentially expressed transporter protein-related genes (DE-TPRGs) were identified from CRC and normal samples using The Cancer Genome Atlas database. SLC38A3 expression was validated by immunohistochemistry and RT-qPCR, and the potential mechanism was explored. A total of 63 DE-TPRGs (29 up-regulated and 34 down-regulated) were screened. Inside, ABCC2, ABCG2, SLC4A4, SLC9A3, SLC15A1, and SLC38A3 were identified as hub genes. SLC38A3 is indeed upregulated in colorectal cancer patients. Furthermore, we found that knockdown of SLC38A3 inhibited the proliferation and migration of HCT116 cells, and Hsp70 ATPase activator could rescue it. Overall, SLC38A3 is a novel potential biomarker involved in CRC progression and promotes the proliferation and migration of tumor cells by positively regulating the function of Hsp70.

Multi-omics analysis reveals the association between specific solute carrier proteins gene expression patterns and the immune suppressive microenvironment in glioma

Glioma is the most prevalent malignant brain tumour. Currently, reshaping its tumour microenvironment has emerged as an appealing strategy to enhance therapeutic efficacy. As the largest group of transmembrane transport proteins, solute carrier proteins (SLCs) are responsible for the transmembrane transport of various metabolites and ions. They play a crucial role in regulating the metabolism and functions of malignant cells and immune cells within the tumour microenvironment, making them a promising target in cancer therapy. Through multidimensional data analysis and experimental validation, we investigated the genetic landscape of SLCs in glioma. We established a classification system comprising 7-SLCs to predict the prognosis of glioma patients and their potential responses to immunotherapy and chemotherapy. Our findings unveiled specific SLC expression patterns and their correlation with the immune-suppressive microenvironment and metabolic status. The 7-SLC classification system was validated in distinguishing subgroups within the microenvironment, specifically identifying subsets involving malignant cells and tumour-associated macrophages. Furthermore, the orphan protein SLC43A3, a core member of the 7-SLC classification system, was identified as a key facilitator of tumour cell proliferation and migration, suggesting its potential as a novel target for cancer therapy.

Protein Signatures of Parathyroid Adenoma according to Tumor Volume and Functionality

BACKGRUOUND

Parathyroid adenoma (PA) is a common endocrine disease linked to multiple complications, but the pathophysiology of the disease remains incompletely understood. The study aimed to identify the key regulator proteins and pathways of PA according to functionality and volume through quantitative proteomic analyses.

METHODS

We conducted a retrospective study of 15 formalin-fixed, paraffin-embedded PA samples from tertiary hospitals in South Korea. Proteins were extracted, digested, and the resulting peptides were analyzed using liquid chromatography-tandem mass spectrometry. Pearson correlation analysis was employed to identify proteins significantly correlated with clinical variables. Canonical pathways and transcription factors were analyzed using Ingenuity Pathway Analysis.

RESULTS

The median age of the participants was 52 years, and 60.0% were female. Among the 8,153 protein groups analyzed, 496 showed significant positive correlations with adenoma volume, while 431 proteins were significantly correlated with parathyroid hormone (PTH) levels. The proteins SLC12A9, LGALS3, and CARM1 were positively correlated with adenoma volume, while HSP90AB2P, HLA-DRA, and SCD5 showed negative correlations. DCPS, IRF2BPL, and FAM98A were the main proteins that exhibited positive correlations with PTH levels, and SLITRK4, LAP3, and AP4E1 had negative correlations. Canonical pathway analysis demonstrated that the RAN and sirtuin signaling pathways were positively correlated with both PTH levels and adenoma volume, while epithelial adherence junction pathways had negative correlations.

CONCLUSION

Our study identified pivotal proteins and pathways associated with PA, offering potential therapeutic targets. These findings accentuate the importance of proteomics in understanding disease pathophysiology and the need for further research.

Drug resistance in ovarian cancer: from mechanism to clinical trial

Ovarian cancer is the leading cause of gynecological cancer-related death. Drug resistance is the bottleneck in ovarian cancer treatment. The increasing use of novel drugs in clinical practice poses challenges for the treatment of drug-resistant ovarian cancer. Continuing to classify drug resistance according to drug type without understanding the underlying mechanisms is unsuitable for current clinical practice. We reviewed the literature regarding various drug resistance mechanisms in ovarian cancer and found that the main resistance mechanisms are as follows: abnormalities in transmembrane transport, alterations in DNA damage repair, dysregulation of cancer-associated signaling pathways, and epigenetic modifications. DNA methylation, histone modifications and noncoding RNA activity, three key classes of epigenetic modifications, constitute pivotal mechanisms of drug resistance. One drug can have multiple resistance mechanisms. Moreover, common chemotherapies and targeted drugs may have cross (overlapping) resistance mechanisms. MicroRNAs (miRNAs) can interfere with and thus regulate the abovementioned pathways. A subclass of miRNAs, "epi-miRNAs", can modulate epigenetic regulators to impact therapeutic responses. Thus, we also reviewed the regulatory influence of miRNAs on resistance mechanisms. Moreover, we summarized recent phase I/II clinical trials of novel drugs for ovarian cancer based on the abovementioned resistance mechanisms. A multitude of new therapies are under evaluation, and the preliminary results are encouraging. This review provides new insight into the classification of drug resistance mechanisms in ovarian cancer and may facilitate in the successful treatment of resistant ovarian cancer.

Comprehensive analyses of solute carrier family members identify SLC12A2 as a novel therapy target for colorectal cancer

As the largest transporter family impacting on tumor genesis and development, the prognostic value of solute carrier (SLC) members has not been elucidated in colorectal cancer (CRC). We aimed to identify a prognostic signature from the SLC members and comprehensively analyze their roles in CRC. Firstly, we downloaded transcriptome data and clinical information of CRC samples from GEO (GSE39582) and TCGA as training and testing dataset, respectively. We extracted the expression matrix of SLC genes and established a prognostic model by univariate and multivariate Cox regression. Afterwards, the low-risk and high-risk group were identified. Then, the differences of prognosis traits, transcriptome features, clinical characteristics, immune infiltration and drug sensitivity between the two groups were explored. Furthermore, molecular subtyping was also implemented by non-negative matrix factorization (NMF). Finally, we studied the expression of the screened SLC genes in CRC tumor tissues and normal tissues as well as investigated the role of SLC12A2 by loss of function and gain of function. As a result, we developed a prognostic risk model based on the screened 6-SLC genes (SLC39A8, SLC2A3, SLC39A13, SLC35B1, SLC4A3, SLC12A2). Both in the training and testing sets, CRC patients in the high-risk group had the poorer prognosis and were in the more advanced pathological stage. What's more, the high-risk group were enriched with CRC progression signatures and immune infiltration. Two groups showed different drug sensitivity. On the other hand, two distinct subclasses (C1 and C2) were identified based on the 6 SLC genes. CRC patients in the high-risk group and C1 subtype had a worse prognosis. Furthermore, we found and validated that SLC12A2 was steadily upregulated in CRC. A loss-of-function study showed that knockdown of SLC12A2 expression restrained proliferation and stemness of CRC cells while a gain-of-function study showed the contrary results. Hence, we provided a 6-SLC gene signature for prognosis prediction of CRC patients. At the same time, we identified that SLC12A2 could promote tumor progression in CRC, which may serve as a potential therapeutic target.

Integrative analysis of co-expression pattern of solute carrier transporters reveals molecular subtypes associated with tumor microenvironment hallmarks and clinical outcomes in colon cancer

Recent findings have suggested that solute carrier (SLC) transporters play an important role in tumor development and progression, and alterations in the expression of individual SLC genes are critical for fulfilling the heightened metabolic requirements of cancerous cells. However, the global influence of the co-expression pattern of SLC transporters on the clinical stratification and characteristics of the tumor microenvironment (TME) remains unexplored. In this study, we identified five SLC gene subtypes based on transcriptome co-expression patterns of 187 SLC transporters by consensus clustering analysis. These subtypes, which were characterized by distinct TME and biological characteristics, were successfully employed for prognostic and chemotherapy response prediction in colon cancer patients, as well as demonstrated associations with immunotherapy benefits. Then, we generated an SLC score model comprising 113 genes to quantify SLC gene co-expression patterns and validated it as an independent prognostic factor and drug response predictor in several independent colon cancer cohorts. Patients with a high SLC score possessed distinct characteristics of copy number variation, genomic mutations, DNA methylation, and indicated an SLC-S2 subtype, which was characterized by strong stromal cell infiltration, stromal pathway activation, poor prognosis, and low predicted fluorouracil and immunotherapeutic responses. Furthermore, the analysis of the Cancer Therapeutics Response Portal database revealed that inhibitors targeting PI3K catalytic subunits could serve as promising chemosensitizing agents for individuals exhibiting high SLC scores. In conclusion, the co-expression patterns of SLC transporters aided the disease classification, and the SLC score proved to be a reliable tool for distinguishing SLC gene subtypes and guiding precise treatment in patients with colon cancer.

Co-expression pattern of SLC transporter genes associated with the immune landscape and clinical outcomes in gastric cancer

Solute carrier (SLC) transporters play a dual role in the occurrence and progression of tumours by acting as both suppressors and promoters. However, the overall impact of SLC transcriptome signatures on the tumour microenvironment, biological behaviour and clinical stratification of gastric cancer has not been thoroughly investigated. Therefore, we comprehensively analysed the expression profiles of the SLC transporter family members to identify novel molecular subtypes in gastric cancer. We identified two distinct SLC subtypes, SLC-S1 and SLC-S2, using non-negative matrix factorization. These subtypes were markedly linked with the tumour microenvironment landscape, biological pathway activation and distinct clinical features of gastric cancer. Furthermore, a new scoring model, the SLC score, was developed to quantify the SLC subtypes. High SLC scores indicated a pattern of 'SLC-S2', characterized by stromal infiltration and activation, poor prognosis and insensitivity to chemotherapy and immunotherapy, but high sensitivity to imatinib. The SLC score could serve as a supplement to the Tumour Node Metastasis (TNM) staging system to guide personalized treatment strategies and predict prognosis for patients with gastric cancer.

Comparative Transcriptome and WGCNA Analysis Reveal Molecular Responses to Salinity Change in Larvae of the Iwagaki Oyster Crassostrea Nippona

The Iwagaki oyster Crassostrea nippona is an important aquaculture species with significant potential for large-scale oyster farming. It is susceptible to the fluctuated salinity in the coastal area. In this study, we compared the transcriptome of Crassostrea nippona larvae under variant conditions with low-salinity stress (28, 20, 15, 10, and 5 practical salinity units (psu)) for 24 h. KEGG enrichment analysis of differentially expressed genes (DEGs) from pairwise comparisons identified several free amino acid metabolism pathway (taurine and hypotaurine, arginine and proline, glycine, and beta-alanine) contributing to the salinity change adaptation and activated "lysosome" and "apoptosis" pathway in response to the low-salinity stress (10 and 5 psu). Trend analysis revealed sustained upregulation of transmembrane transport-related genes (such as SLC family) and downregulation of ribosomal protein synthesis genes faced with decreasing salinities. In addition, 9 biomarkers in response to low-salinity stress were identified through weighted gene co-expression network analysis (WGCNA) and validated by qRT-PCR. Our transcriptome analysis provides a comprehensive view of the molecular mechanisms and regulatory networks underlying the adaptive responses of oyster larvae to hypo-salinity conditions. These findings contribute to our understanding of the complex biological processes involved in oyster resilience and adaptation to changing environmental conditions.

In silico analysis of the solute carrier (SLC) family in cancer indicates a link among DNA methylation, metabolic adaptation, drug response, and immune reactivity

Introduction: The oncogenic transformation is driven by genetic and epigenetic alterations influencing cancer cell fate. These alterations also result in metabolic reprogramming by modulating the expression of membrane Solute Carrier (SLC) transporters involved in biomolecules trafficking. SLCs act as tumor suppressors or promoters influencing cancer methylome, tumor growth, immune-escape, and chemoresistance. Methods: This in silico study aimed to identify the deregulated SLCs in various tumor types compared to normal tissues by analyzing the TCGA Target GTEx dataset. Furthermore, the relationship between SLCs expression and the most relevant tumor features was tackled along with their genetic regulation mediated by DNA methylation. Results: We identified 62 differentially expressed SLCs, including the downregulated SLC25A27 and SLC17A7, as well as the upregulated SLC27A2 and SLC12A8. Notably, SLC4A4 and SLC7A11 expression was associated with favorable and unfavorable outcome, respectively. Moreover, SLC6A14, SLC34A2, and SLC1A2 were linked to tumor immune responsiveness. Interestingly, SLC24A5 and SLC45A2 positively correlated with anti-MEK and anti-RAF sensitivity. The expression of relevant SLCs was correlated with hypo- and hyper-methylation of promoter and body region, showing an established DNA methylation pattern. Noteworthy, the positive association of cg06690548 (SLC7A11) methylation with cancer outcome suggests the independent predictive role of DNA methylation at a single nucleotide resolution. Discussion: Although our in silico overview revealed a wide heterogeneity depending on different SLCs functions and tumor types, we identified key SLCs and pointed out the role of DNA methylation as regulatory mechanism of their expression. Overall, these findings deserve further studies to identify novel cancer biomarkers and promising therapeutic targets.

Upregulation of SLC12A3 and SLC12A9 Mediated by the HCP5/miR-140-5p Axis Confers Aggressiveness and Unfavorable Prognosis in Uveal Melanoma

Perturbation of solute carriers (SLCs) has been implicated in metabolic disorders and cancer, highlighting the potential for drug discovery and therapeutic opportunities. However, there is relatively little exploration of the clinical relevance and potential molecular mechanisms underlying the role of the SLC12 family in uveal melanoma (UVM). Here, we performed an integrative multiomics analysis of the SLC12 family in multicenter UVM datasets and found that high expression of SLC12A3 and SLC12A9 was associated with unfavorable prognosis. Moreover, SLC12A3 and SLC12A9 were highly expressed in UVM in vivo. We experimentally characterized the roles of these proteins in tumorigenesis in vitro and explored their association with the prognosis of UVM. Lastly, we identified the HCP5-miR-140-5p axis as a potential noncoding RNA pathway upstream of SLC12A3 and SLC12A9, which was associated with immunomodulation and may represent a novel predictor for clinical prognosis and responsiveness to checkpoint blockade immunotherapy. These findings may facilitate a better understanding of the SLCome and guide future rationalized development of SLC-targeted therapy and drug discovery for UVM.

The Biosynthesis Related Enzyme, Structure Diversity and Bioactivity Abundance of Indole-Diterpenes: A Review

Indole diterpenes are a large class of secondary metabolites produced by fungi, possessing a cyclic diterpenoid backbone and an indole moiety. Novel structures and important biological activity have made indole diterpenes one of the focuses of synthetic chemists. Although the discovery, identification, structural diversity, biological activity and especially structure-activity relationship of indole diterpenes have been reported in some papers in recent years, they are absent of a systematic and comprehensive analysis, and there is no elucidation of enzymes related to this kind of natural product. Therefore, it is necessary to summarize the relevant reports to provide new perspectives for the following research. In this review, for the first time, the function of related synthases and the structure-activity relationship of indole diterpenes are expounded, and the recent research advances of them are emphasized.

Effect of High-Quality Nursing Intervention on the Quality of Life and Psychological State of Tumor Patients Undergoing First Chemotherapy

This study aimed to investigate the effect of high-quality nursing intervention on the quality of life (QOL) and psychological state of patients undergoing chemotherapy for the first time. A total of 100 malignant tumor patients admitted to Jiangyin Hospital of Traditional Chinese Medicine to receive chemotherapy for the first time from October 2018 to July 2020 were selected and randomized either to the control group or to the study group (50 cases in each group) via the random number table method. The control group received routine nursing, while the study group received high-quality nursing intervention. There was no striking difference in self-rating anxiety scale (SAS), self-rating depression scale (SDS), Karnofsky score (KPS), Eastern Cooperative Oncology Group (ECOG), and QOL between the two groups before nursing intervention (all P > 0.05). After nursing intervention, the SAS, SDS, KPS, ECOG, and QOL in the study group were better than those in the control group (all P < 0.05). The adverse reaction scores of the patients in the study group were lower than those in the control group (P < 0.05). High-quality nursing intervention can effectively reduce the psychological pressure of the first chemotherapy for patients with malignant tumor, ameliorate the psychological burden of patients, relieve patients' anxiety and fear, thus improve the chemotherapy effect, and contribute to improve their QOL.

MicroRNAs in the Regulation of Solute Carrier Proteins Behind Xenobiotic and Nutrient Transport in Cells

Altered metabolism, such as aerobic glycolysis or the Warburg effect, has been recognized as characteristics of tumor cells for almost a century. Since then, there is accumulating evidence to demonstrate the metabolic reprogramming of tumor cells, addiction to excessive uptake and metabolism of key nutrients, to support rapid proliferation and invasion under tumor microenvironment. The solute carrier (SLC) superfamily transporters are responsible for influx or efflux of a wide variety of xenobiotic and metabolites that are needed for the cells to function, as well as some medications. To meet the increased demand for nutrients and energy, SLC transporters are frequently dysregulated in cancer cells. The SLCs responsible for the transport of key nutrients for cancer metabolism and energetics, such as glucose and amino acids, are of particular interest for their roles in tumor progression and metastasis. Meanwhile, rewired metabolism is accompanied by the dysregulation of microRNAs (miRNAs or miRs) that are small, noncoding RNAs governing posttranscriptional gene regulation. Studies have shown that many miRNAs directly regulate the expression of specific SLC transporters in normal or diseased cells. Changes of SLC transporter expression and function can subsequently alter the uptake of nutrients or therapeutics. Given the important role for miRNAs in regulating disease progression, there is growing interest in developing miRNA-based therapies, beyond serving as potential diagnostic or prognostic biomarkers. In this article, we discuss how miRNAs regulate the expression of SLC transporters and highlight potential influence on the supply of essential nutrients for cell metabolism and drug exposure toward desired efficacy.

An integrated bioinformatic investigation of mitochondrial solute carrier family 25 (SLC25) in colon cancer followed by preliminary validation of member 5 (SLC25A5) in tumorigenesis

Solute carrier family 25 (SLC25) encodes transport proteins at the inner mitochondrial membrane and functions as carriers for metabolites. Although SLC25 genetic variants correlate with human metabolic diseases, their roles in colon cancer remain unknown. Cases of colon cancer were retrieved from The Cancer Genome Atlas, and the transcriptionally differentially expressed members (DEMs) of SLC25 were identified. DNA level alterations, clinicopathological characteristics, and clinical survival were also investigated. A risk score model based on the DEMs was constructed to further evaluate their prognostic values in a clinical setting. The results were preliminarily validated using bioinformatic analysis of datasets from the Gene Expression Omnibus, immunohistochemical evaluations in clinical specimens, and functional experiments in colon cancer-derived cell lines. Thirty-seven DEMs were identified among 53 members of SLC25. Eight of 37 DEMs were introduced into a risk score model using integrated LASSO regression and multivariate Cox regression. Validated by GSE395282 and GSE175356, DEMs with high-risk scores were associated with the phenotypes of increasing tumor immune infiltration and decreasing glycolysis and apoptosis contents. SLC25A5 was downregulated in cancer, and its upregulation was related to better overall survival in patients from public datasets and in clinical cases. High SLC25A5 expression was an independent prognostic factor for 79 patients after surgical treatment. A negative correlation between CD8 and SLC25A5 was determined in specimens from 106 patients with advanced colon cancer. SLC25A5 attenuated cell proliferation, upregulated the expression of programmed cell death-related signatures, and exerted its biological function by inhibiting the MAPK signaling pathway. Our study reveals that mitochondrial SLC25 has prognostic value in patients with colon cancer. The bioinformatic analyses by following verification in situ and in vitro provide direction for further functional and mechanistic studies on the identified member of SLC25.

The Important Role of Ion Transport System in Cervical Cancer

Cervical cancer is a significant gynecological cancer and causes cancer-related deaths worldwide. Human papillomavirus (HPV) is implicated in the etiology of cervical malignancy. However, much evidence indicates that HPV infection is a necessary but not sufficient cause in cervical carcinogenesis. Therefore, the cellular pathophysiology of cervical cancer is worthy of study. This review summarizes the recent findings concerning the ion transport processes involved in cell volume regulation and intracellular Ca²⁺ homeostasis of epithelial cells and how these transport systems are themselves regulated by the tumor microenvironment. For cell volume regulation, we focused on the volume-sensitive Cl⁻ channels and K⁺-Cl⁻ cotransporter (KCC) family, important regulators for ionic and osmotic homeostasis of epithelial cells. Regarding intracellular Ca²⁺ homeostasis, the Ca²⁺ store sensor STIM molecules and plasma membrane Ca²⁺ channel Orai proteins, the predominant Ca²⁺ entry mechanism in epithelial cells, are discussed. Furthermore, we evaluate the potential of these membrane ion transport systems as diagnostic biomarkers and pharmacological interventions and highlight the challenges.

Identification of ferroptosis-related genes as potential biomarkers of tongue squamous cell carcinoma using an integrated bioinformatics approach

Tongue squamous cell carcinoma (TSCC) is one of the deadliest cancers of the head and neck, but the role of the ferroptosis pathway in its development is still unknown. In this study we explored the pathogenetic mechanisms associated with ferroptosis in TSCC. We identified differentially expressed genes (DEGs) of TSCC patients and used gene ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA) to annotate, visualize, and integrate these DEGs. Receiver operating characteristic curve (ROC) analysis was performed, and the STRING database was used to construct a protein–protein interaction network to evaluate the predictive value of ferroptosis‐related DEGs. A total of 219 DEGs were identified and GO, KEGG, and GSEA showed that extracellular matrix (ECM)‐receptor interaction and interleukin (IL)‐17 signaling pathways were substantially upregulated in TSCC. Univariate Cox analysis revealed that high expression of CA9, TNFAIP3, and NRAS were predictive of a worse outcome. We then constructed a prognostic model that predicted survival in the validation cohort at 1 year and 32 months. Finally, 60 cases of tongue carcinoma and normal tissues were collected, and immunohistochemistry was used to detect the expression of CA9. We found that CA9 was strongly expressed in tongue carcinoma tissues and absent in adjacent tissues. Overall, we found that ferroptosis‐related genes may affect TSCC prognosis through the ECM‐receptor interaction and IL‐17 signaling pathways. Additionally, immunohistochemistry confirmed that CA9 was highly expressed in tongue carcinoma tissues, and a model based on ferroptosis‐related genes showed a good ability to predict overall survival in TSCC.