GATA6 enhances the stemness of human colon cancer cells by creating a metabolic symbiosis through upregulating LRH-1 expression

Liver receptor homolog-1: structures, related diseases, and drug discovery

Liver receptor homolog-1 (LRH-1), a member of the nuclear receptor superfamily, is a ligand-regulated transcription factor that plays crucial roles in metabolism, development, and immunity. Despite being classified as an 'orphan' receptor due to the ongoing debate surrounding its endogenous ligands, recent researches have demonstrated that LRH-1 can be modulated by various synthetic ligands. This highlights the potential of LRH-1 as an attractive drug target for the treatment of inflammation, metabolic disorders, and cancer. In this review, we provide an overview of the structural basis, functional activities, associated diseases, and advancements in therapeutic ligand research targeting LRH-1.

The emerging role of lactate in tumor microenvironment and its clinical relevance

In recent years, the significant impact of lactate in the tumor microenvironment has been greatly documented. Acting not only as an energy substance in tumor metabolism, lactate is also an imperative signaling molecule. It plays key roles in metabolic remodeling, protein lactylation, immunosuppression, drug resistance, epigenetics and tumor metastasis, which has a tight relation with cancer patients' poor prognosis. This review illustrates the roles lactate plays in different aspects of tumor progression and drug resistance. From the comprehensive effects that lactate has on tumor metabolism and tumor immunity, the therapeutic targets related to it are expected to bring new hope for cancer therapy.

From metabolism to malignancy: the multifaceted role of PGC1α in cancer

PGC1α, a central player in mitochondrial biology, holds a complex role in the metabolic shifts seen in cancer cells. While its dysregulation is common across major cancers, its impact varies. In some cases, downregulation promotes aerobic glycolysis and progression, whereas in others, overexpression escalates respiration and aggression. PGC1α's interactions with distinct signaling pathways and transcription factors further diversify its roles, often in a tissue-specific manner. Understanding these multifaceted functions could unlock innovative therapeutic strategies. However, challenges exist in managing the metabolic adaptability of cancer cells and refining PGC1α-targeted approaches. This review aims to collate and present the current knowledge on the expression patterns, regulators, binding partners, and roles of PGC1α in diverse cancers. We examined PGC1α's tissue-specific functions and elucidated its dual nature as both a potential tumor suppressor and an oncogenic collaborator. In cancers where PGC1α is tumor-suppressive, reinstating its levels could halt cell proliferation and invasion, and make the cells more receptive to chemotherapy. In cancers where the opposite is true, halting PGC1α's upregulation can be beneficial as it promotes oxidative phosphorylation, allows cancer cells to adapt to stress, and promotes a more aggressive cancer phenotype. Thus, to target PGC1α effectively, understanding its nuanced role in each cancer subtype is indispensable. This can pave the way for significant strides in the field of oncology.

NR5A2 gene affects the overall survival of LUAD patients by regulating the activity of CSCs through SNP pathway by OCLR algorithm and immune score

Objective

Differentially expressed genes (DEGs) in lung adenocarcinoma (LUAD) tumor stem cells were screened, and the biological characteristics of NR5A2 gene were investigated.

Methods

The expression and prognosis of NR5A2 in human LUAD were predicted and analyzed through bioinformatics analysis from a human cancer database. Gene expression and clinical data of LUAD tumor and normal lung tissues were obtained from The Cancer Genome Atlas (TCGA) database, and DEGs associated with lung cancer tumor stem cells (CSCs) were screened. Univariate and multivariate Cox regression models were used to screen and establish prognostic risk prediction models. The immune function of the patients was scored according to the model, and the relative immune functions of the high- and low-risk groups were compared to determine the difference in survival prognosis between the two groups. In addition, we calculated the index of stemness based on the transcriptome of the samples using one-class linear regression (OCLR).

Results

Bioinformatics analysis of a clinical cancer database showed that NR5A2 was significantly decreased in human LUAD tissues than in normal lung tissues, and the decrease in NR5A2 gene expression shortened the overall survival and progression-free survival of patients with LUAD.

Conclusion

The NR5A2 gene may regulate LUAD tumor stem cells through selective splicing mutations, thereby affecting the survival and prognosis of patients with lung cancer, and the NR5A2 gene may regulate CSCs through single nucleotide polymorphism.

Delineating the role of nuclear receptors in colorectal cancer, a focused review

Colorectal cancer (CRC) stands as one of the most prevalent form of cancer globally, causing a significant number of deaths, surpassing 0.9 million in the year 2020. According to GLOBOCAN 2020, CRC ranks third in incidence and second in mortality in both males and females. Despite extensive studies over the years, there is still a need to establish novel therapeutic targets to enhance the patients' survival rate in CRC. Nuclear receptors (NRs) are ligand-activated transcription factors (TFs) that regulate numerous essential biological processes such as differentiation, development, physiology, reproduction, and cellular metabolism. Dysregulation and anomalous expression of different NRs has led to multiple alterations, such as impaired signaling cascades, mutations, and epigenetic changes, leading to various diseases, including cancer. It has been observed that differential expression of various NRs might lead to the initiation and progression of CRC, and are correlated with poor survival outcomes in CRC patients. Despite numerous studies on the mechanism and role of NRs in this cancer, it remains of significant scientific interest primarily due to the diverse functions that various NRs exhibit in regulating key hallmarks of this cancer. Thus, modulating the expression of NRs with their agonists and antagonists, based on their expression levels, holds an immense prospect in the diagnosis, prognosis, and therapeutical modalities of CRC. In this review, we primarily focus on the role and mechanism of NRs in the pathogenesis of CRC and emphasized the significance of targeting these NRs using a variety of agents, which may represent a novel and effective strategy for the prevention and treatment of this cancer.

Intratumoral metabolic heterogeneity of colorectal cancer

Although the metabolic phenotype within tumors is known to differ significantly from that of the surrounding normal tissue, the importance of this heterogeneity is just becoming widely recognized. Colorectal cancer (CRC) is often classified as the Warburg phenotype, a metabolic type in which the glycolytic system is predominant over oxidative phosphorylation (OXPHOS) in mitochondria for energy production. However, this dichotomy (glycolysis vs. OXPHOS) may be too simplistic and not accurately represent the metabolic characteristics of CRC. Therefore, in this review, we decompose metabolic phenomena into factors based on their source/origin and reclassify them into two categories: extrinsic and intrinsic. In the CRC context, extrinsic factors include those based on the environment, such as hypoxia, nutrient deprivation, and the tumor microenvironment, whereas intrinsic factors include those based on subpopulations, such as pathological subtypes and cancer stem cells. These factors form multiple layers inside and outside the tumor, affecting them additively, dominantly, or mutually exclusively. Consequently, the metabolic phenotype is a heterogeneous and fluid phenomenon reflecting the spatial distribution and temporal continuity of these factors. This allowed us to redefine the characteristics of specific metabolism-related factors in CRC and summarize and update our accumulated knowledge of their heterogeneity. Furthermore, we positioned tumor budding in CRC as an intrinsic factor and a novel form of metabolic heterogeneity, and predicted its metabolic dynamics, noting its similarity to circulating tumor cells and epithelial-mesenchymal transition. Finally, the possibilities and limitations of using human tumor tissue as research material to investigate and assess metabolic heterogeneity are discussed.

OCTN2 enhances PGC-1α-mediated fatty acid oxidation and OXPHOS to support stemness in hepatocellular carcinoma

BACKGROUND

The Metabolic reprogramming of tumor cells plays a vital role in the progression of hepatocellular carcinoma. Organic cation/carnitine transporter 2 (OCTN2), a sodium-ion dependent carnitine transporter and a sodium-ion independent tetraethylammonium (TEA) transporter, has been reported to contribute tumor malignancies and metabolic dysregulation in renal and esophageal carcinoma. However, the role of lipid metabolism deregulation mediated by OCTN2 in HCC cells has not been clarified.

METHODS

Bioinformatics analyses and immunohistochemistry assay were employed to identify OCTN2 expression in HCC tissues. The correlation between OCTN2 expression and prognosis was elucidated through K-M survival analysis. The expression and function of OCTN2 were examined via the assays of western blotting, sphere formation, cell proliferation, migration and invasion. The mechanism of OCTN2-mediated HCC malignancies was investigated through RNA-seq and metabolomic analyses. Furthermore, xenograft tumor models based on HCC cells with different OCTN2 expression levels were conducted to analyze the tumorigenic and targetable role of OCTN2 in vivo.

RESULTS

We found that gradually focused OCTN2 was significantly upregulated in HCC and tightly associated with poor prognosis. Additionally, OCTN2 upregulation promoted HCC cells proliferation and migration in vitro and augmented the growth and metastasis of HCC. Moreover, OCTN2 promoted the cancer stem-like properties of HCC by increasing fatty acid oxidation and oxidative phosphorylation. Mechanistically, PGC-1α signaling participated in the HCC cancer stem-like properties mediated by OCTN2 overexpression, which is confirmed by in vitro and in vivo analyses. Furthermore, OCTN2 upregulation may be transcriptionally activated by YY1 in HCC. Particularly, treatment with mildronate, an inhibitor of OCTN2, showed a therapeutic influence on HCC in vitro and in vivo.

CONCLUSIONS

Our findings demonstrate that OCTN2 plays a critical metabolic role in HCC cancer stemness maintenance and HCC progression, providing evidence for OCTN2 as a promising target for HCC therapy.

E2F3 accelerates the stemness of colon cancer cells by activating the STAT3 pathway

Introduction

Colon cancer is one of the most prevalent malignancies and causes of cancer-related deaths worldwide. Thus, further research is required to explicate the latent molecular mechanisms and look for novel biomarkers. E2F3 has been confirmed to be an oncogene in a variety of cancers. However, the particular regulation of E2F3 in colon cancer needs further investigation.

Methods

The self-renewal ability was detected through a sphere formation assay. The tumorigenic ability was measured through nude mice in vivo assay. The protein expression of genes was examined through a Western blot. The expression of E2F3 in tumor tissues was detected through an IHC assay. The resistance to cisplatin was assessed through the CCK-8 assay. The cell migration and invasion abilities were measured after upregulating or suppressing E2F3 through the Transwell assay.

Results

Results uncovered that E2F3 was upregulated in spheroid cells. In addition, E2F3 facilitates stemness in colon cancer. Moreover, E2F3 facilitated colon cancer cell migration and invasion. Finally, it was revealed that E2F3 affected the STAT3 pathway to modulate stemness in colon cancer. E2F3 served as a promoter regulator in colon cancer, aggravating tumorigenesis and stemness in colon cancer progression through the STAT3 pathway.

Conclusion

E2F3 may be a useful biomarker for anticancer treatment in colon cancer.

Mitochondria in colorectal cancer stem cells - a target in drug resistance

Colorectal cancer (CRC) is the third most diagnosed cancer and the second most deadly type of cancer worldwide. In late diagnosis, CRC can resist therapy regimens in which cancer stem cells (CSCs) are intimately related. CSCs are a subpopulation of tumor cells responsible for tumor initiation and maintenance, metastasis, and resistance to conventional treatments. In this scenario, colorectal cancer stem cells (CCSCs) are considered an important key for therapeutic failure and resistance. In its turn, mitochondria is an organelle involved in many mechanisms in cancer, including chemoresistance of cytotoxic drugs due to alterations in mitochondrial metabolism, apoptosis, dynamics, and mitophagy. Therefore, it is crucial to understand the mitochondrial role in CCSCs regarding CRC drug resistance. It has been shown that enhanced anti-apoptotic protein expression, mitophagy rate, and addiction to oxidative phosphorylation are the major strategies developed by CCSCs to avoid drug insults. Thus, new mitochondria-targeted drug approaches must be explored to mitigate CRC chemoresistance via the ablation of CCSCs.

Distinct Myeloid Derived Suppressor Cell Populations Promote Tumor Aggression in Glioblastoma

The diversity of genetic programs and cellular plasticity of glioma-associated myeloid cells, and thus their contribution to tumor growth and immune evasion, is poorly understood. We performed single cell RNA-sequencing of immune and tumor cells from 33 glioma patients of varying tumor grades. We identified two populations characteristic of myeloid derived suppressor cells (MDSC), unique to glioblastoma (GBM) and absent in grades II and III tumors: i) an early progenitor population (E-MDSC) characterized by strong upregulation of multiple catabolic, anabolic, oxidative stress, and hypoxia pathways typically observed within tumor cells themselves, and ii) a monocytic MDSC (M-MDSC) population. The E-MDSCs geographically co-localize with a subset of highly metabolic glioma stem-like tumor cells with a mesenchymal program in the pseudopalisading region, a pathognomonic feature of GBMs associated with poor prognosis. Ligand-receptor interaction analysis revealed symbiotic cross-talk between the stemlike tumor cells and E-MDSCs in GBM, whereby glioma stem cells produce chemokines attracting E-MDSCs, which in turn produce growth and survival factors for the tumor cells. Our large-scale single-cell analysis elucidated unique MDSC populations as key facilitators of GBM progression and mediators of tumor immunosuppression, suggesting that targeting these specific myeloid compartments, including their metabolic programs, may be a promising therapeutic intervention in this deadly cancer.

One-Sentence Summary

Aggressive glioblastoma harbors two unique myeloid populations capable of promoting stem-like properties of tumor cells and suppressing T cell function in the tumor microenvironment.

Circ_0008717 Sponges miR-326 to Elevate GATA6 Expression to Promote Breast Cancer Tumorigenicity

Circular RNAs (circRNAs) have been reported to paly roles in the progression and management of breast cancers (BC). This work aimed to detect the role and mechanism of circ_0008717 in BC tumorigenesis. Expression levels of genes and proteins were evaluated by quantitative real-time polymerase chain reaction and western blot. In vitro assays were conducted using cell counting kit-8, colony formation, transwell, tube formation, and flow cytometry assays, respectively. The interaction between miR-326 and circ_0008717 or GATA6 (GATA Binding Protein six) was confirmed by bioinformatics analysis, and dual-luciferase reporter assay and RNA immunoprecipitation assay. The murine xenograft models were established to perform in vivo assay. Circ_0008717 and GATA6 were highly expressed, while miR-326 was lowly expressed in BC tissues and cells. Functionally, knockdown of circ_0008717 not only suppressed breast cancer cell proliferation, angiogenesis, migration, invasion and epithelial-mesenchymal transition (EMT) in vitro, but also hindered tumor growth and EMT process in vivo. Mechanistically, Circ_0008717 directly bound to miR-326, which targeted GATA6. Rescue experiments showed that miR-326 reversed the anticancer action of circ_0008717 knockdown on BC cells. Moreover, miR-326 restoration repressed BC cell growth and metastasis, which were attenuated by GATA6 overexpression. In addition, we also observed that circ_0008717 could regulate GATA6 expression by sponging miR-326. Circ_0008717 promoted breast cancer growth and metastasis through miR-326/GATA6 axis, revealing a potential therapeutic target for breast cancer treatment.

LRH-1 high expression in the ovarian granulosa cells of PCOS patients

PURPOSE

Polycystic ovary syndrome (PCOS) is considered one of the most common endocrine disorders with heterogeneity. There are also reports that liver receptor homolog 1 [LRH-1 or nuclear receptor subfamily 5 group A member 2] plays an important role in the reproductive system. But up to now, there are no reports related to the link with PCOS and LRH-1. In this study, we aimed to detect the LRH-1 expression in the ovarian granulosa cell (GC) of PCOS patients and explore the potential relationship between LRH-1 and PCOS.

METHODS

In all, 146 follicular fluid samples were collected in this study, including 72 from PCOS patients and 74 from control patients who underwent intracytoplasmic sperm injection or in vitro fertilization-embryo transfer. The ovarian GCs were extracted from the patient's follicular fluid by magnetic-activated cell sorting method, and real-time quantitative PCR was used to measure the expression of LRH-1 in ovarian GCs. Then we analyzed the correlation between the expression level of LRH-1 and the clinical characteristics of the patient by using Pearson Correlation analysis.

RESULTS

The expression of LRH-1 was significantly higher in PCOS patients ovarian GCs than that in the control patients [(1.38 ± 0.47) vs (1.03 ± 0.32), t = 5.327, p < 0.0001], and it was positively correlated with antral follicles counting (r = 0.3607, p < 0.0001) and the serum anti-Mullerian hormone (r = 0.2662, p = 0.0012), luteotropic hormone (r = 0.2518, p = 0.0022), testosterone (r = 0.2794, p = 0.0006) in all patients. No statistical significance between LRH-1 and body mass index, follicle-stimulating hormone, homeostasis model assessment of insulin resistance, dehydroepiandrosterone sulfate, progesterone.

CONCLUSIONS

Compared with the control group, we found that LRH-1 was highly expressed in the ovarian GCs of PCOS patients. Our study has revealed the relationship between the LRH-1 expression and PCOS, which suggested that LRH-1 may play an important role in ovulation disorders. While this finding provided new ideas for the study of pathogenesis, it also provided a theoretical basis for the clinical diagnosis and treatment for PCOS.

Hypoxia effects on cancer stem cell phenotype in colorectal cancer: a mini-review

Colorectal cancer (CRC) is ranked third most incident and second most deadly around the world, and even though treatments significantly developed over the years, overall survival remains low. This scenario has the contribution of cancer stem cells (CSC), a subpopulation of the heterogeneous tumor bulk, considered to be responsible for the tumor maintenance, conventional therapies resistance, metastasis, and recurrence. In this regard, hypoxia appears as an important component of tumor microenvironment and CSC niche, being associated with a worse prognosis. Therefore, it is vital the study of hypoxia influence on CSC phenotype in CRC. The aim of this mini-review article is to present a brief overview on this field. Recent articles discoursed about CSC molecular regulation, signalling pathways, methods for the study of the topic, as well as molecules and drugs capacity of inhibiting the interplay of hypoxia-CSC. Finally, the studies demonstrated important results, extensively accessing the topics of cellular and molecular regulation and therapeutic intervention, being morphology an area to be more explored.

Identification of Hub Genes and Construction of a Transcriptional Regulatory Network Associated With Tumor Recurrence in Colorectal Cancer by Weighted Gene Co-expression Network Analysis

Tumor recurrence is one of the most important risk factors that can negatively affect the survival rate of colorectal cancer (CRC) patients. However, the key regulators dictating this process and their exact mechanisms are understudied. This study aimed to construct a gene co-expression network to predict the hub genes affecting CRC recurrence and to inspect the regulatory network of hub genes and transcription factors (TFs). A total of 177 cases from the GSE17536 dataset were analyzed via weighted gene co-expression network analysis to explore the modules related to CRC recurrence. Functional annotation of the key module genes was assessed through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. The protein and protein interaction network was then built to screen hub genes. Samples from the Cancer Genome Atlas (TCGA) were further used to validate the hub genes. Construction of a TFs-miRNAs–hub genes network was also conducted using StarBase and Cytoscape approaches. After identification and validation, a total of five genes (TIMP1, SPARCL1, MYL9, TPM2, and CNN1) were selected as hub genes. A regulatory network of TFs-miRNAs-targets with 29 TFs, 58 miRNAs, and five hub genes was instituted, including model GATA6-MIR106A-CNN1, SP4-MIR424-TPM2, SP4-MIR326-MYL9, ETS1-MIR22-TIMP1, and ETS1-MIR22-SPARCL1. In conclusion, the identification of these hub genes and the prediction of the Regulatory relationship of TFs-miRNAs-hub genes may provide a novel insight for understanding the underlying mechanism for CRC recurrence.

Another One Bites the Gut: Nuclear Receptor LRH-1 in Intestinal Regeneration and Cancer

The process of self-renewal in normal intestinal epithelium is characterized by a fine balance between proliferation, differentiation, migration, and cell death. When even one of these aspects escapes the normal control, cellular proliferation and differentiation are impaired, with consequent onset of tumorigenesis. In humans, colorectal cancer (CRC) is the main pathological manifestation of this derangement. Nowadays, CRC is the world's fourth most deadly cancer with a limited survival after treatment. Several conditions can predispose to CRC development, including dietary habits and pre-existing inflammatory bowel diseases. Given their extraordinary ability to interact with DNA, it is widely known that nuclear receptors play a key role in the regulation of intestinal epithelium, orchestrating the expression of a series of genes involved in developmental and homeostatic pathways. In particular, the nuclear receptor Liver Receptor Homolog-1 (LRH-1), highly expressed in the stem cells localized in the crypts, promotes intestine cell proliferation and renewal in both direct and indirect DNA-binding manner. Furthermore, LRH-1 is extensively correlated with diverse intestinal inflammatory pathways. These evidence shed a light in the dynamic intestinal microenvironment in which increased regenerative epithelial cell turnover, mutagenic insults, and chronic DNA damages triggered by factors within an inflammatory cell-rich microenvironment act synergistically to favor cancer onset and progression.

Role of hypoxia inducible factor-1 in cancer stem cells (Review)

Cancer stem cells (CSCs) have been found to play a decisive role in cancer recurrence, metastasis, and chemo‑, radio‑ and immuno‑resistance. Understanding the mechanism of CSC self‑renewal and proliferation may help overcome the limitations of clinical treatment. The microenvironment of tumor growth consists of a lack of oxygen, and hypoxia has been confirmed to induce cancer cell invasion, metastasis and epithelial‑mesenchymal transition, and is usually associated with poor prognosis and low survival rates. Hypoxia inducible factor‑1 (HIF‑1) can be stably expressed under hypoxia and act as an important molecule to regulate the development of CSCs, but the specific mechanism remains unclear. The present review attempted to explain the role of HIF‑1 in the generation and maintenance of CSCs from the perspective of epigenetics, metabolic reprogramming, tumor immunity, CSC markers, non‑coding RNA and signaling pathways associated with HIF‑1, in order to provide novel targets with HIF‑1 as the core for clinical treatment, and extend the life of patients.

lncRNA HotairM1 Depletion Promotes Self-Renewal of Cancer Stem Cells through HOXA1-Nanog Regulation Loop

In cancer cells, a gain of stemness may have profound implications for tumor initiation, aggressiveness, and clinical outcome. However, the molecular mechanisms underlying the self-renewal maintenance of cancer stem-like cells (CSCs) remain elusive. Here, based on analysis of transcriptome sequencing, we identified a long noncoding RNA (lncRNA) named HotairM1, which is weakly expressed in human colorectal carcinoma and uveal melanoma, and a much lower expression in corresponding CSCs. Our results showed that HotairM1 depletion could promote CSC self-renewal and tumor propagation. Mechanistically, HotairM1 recruit EZH2 and SUZ12 to the promoter of its target gene HOXA1, leading to histone H3K27 trimethylation and epigenetic silencing of HOXA1. The silence of HOXA1 subsequently induces the H3K27 acetylation at the enhancer site of Nanog gene to upregulate its expression. The enrichment of Nanog could further inhibit HOXA1 expression, forming a reciprocal regulation loop augmenting the stemness maintaining effect. In summary, our results revealed a lncRNA-based regulatory loop that sustains self-renewal of CSCs, which highlights the critical role of HotairM1 in CSC development through the HOXA1-Nanog signaling loop.

NR5A2 synergizes with NCOA3 to induce breast cancer resistance to BET inhibitor by upregulating NRF2 to attenuate ferroptosis

BET inhibitors (BETi) exert an excellent anti-cancer activity in breast cancer. However, the identification of new potential targets to enhance breast cancer sensitivity to BETi is still an enormous challenge. Both NR5A2 and NCOA3 are frequently involved in cancer cells resistance to chemotherapy, also associated with poor prognosis in breast cancer. However, the functions of NR5A2 and NCOA3 in BETi resistance remains unknown. In this study, we found that BETi JQ1 and I-BET151 exhibited anti-cancer effects in breast cancer by inducing ferroptosis. NCOA3 as a coactivator synergized with NR5A2 to prevent BETi-induced ferroptosis. Mechanistically, we identified NR5A2 synergized with NCOA3 to increase expression of NRF2, a transcription factor that controls the expression of many antioxidant genes. Moreover, inhibition of NR5A2 or NCOA3 using small molecule inhibitors enhanced anti-cancer effects of BETi against breast cancer in vivo and in vitro. Altogether, our findings illustrated NR5A2 synergized with NCOA3 to confer breast cancer cells resistance to BETi by induction of NRF2. Inhibition of NR5A2/NCOA3 combined with BETi might be a novel strategy for treatment of breast cancer.