Estrogen and ERα enhanced β-catenin degradation and suppressed its downstream target genes to block the metastatic function of HA22T hepatocellular carcinoma cells via modulating GSK-3β and β-TrCP expression

Beta-Transducin Repeats-Containing Proteins as an Anticancer Target

Beta-transducin repeat-containing proteins (β-TrCPs) are E3-ubiquitin-ligase-recognizing substrates and regulate proteasomal degradation. The degradation of β-TrCPs' substrates is tightly controlled by various external and internal signaling and confers diverse cellular processes, including cell cycle progression, apoptosis, and DNA damage response. In addition, β-TrCPs function to regulate transcriptional activity and stabilize a set of substrates by distinct mechanisms. Despite the association of β-TrCPs with tumorigenesis and tumor progression, studies on the mechanisms of the regulation of β-TrCPs' activity have been limited. In this review, we studied publications on the regulation of β-TrCPs themselves and analyzed the knowledge gaps to understand and modulate β-TrCPs' activity in the future.

The estrogen/miR-338-3p/ADAM17 axis enhances the viability of breast cancer cells via suppressing NK cell's function

Natural killer (NK) cells are the critical elements of the innate immune response and implicated in rapidly recognizing and eliminating cancer cells. However, the tumor-suppressive ability of NK cells is often impaired in several cancer types. The critical roles of microRNAs have been elucidated by increasing evidences, while the regulation of miR-338-3p in anti-tumor activation of NK cells and its relationship with estrogen in breast cancer (BC) are still confusing. Here, miR-338-3p level was found to be significantly downregulated in BC tissues and estrogen receptor positive (ER+ ) cells, this difference was more obvious in ER+ patients or BC patients at advanced stage (TNM III and IV). MiR-338-3p level was shown to be downregulated by 17β-estradiol in BC cells (MDA-MB-231 cells and MCF-7) in vitro. MiR-338-3p overexpression decreased disintegrin and metalloprotease-17 (ADAM17) secretion in MDA-MB-231 (ER- ) and MCF-7 (ER+ ) cells. In addition, miR-338-3p overexpression or treatment with anti-ADAM17 antibody could down-regulate granzyme B, CD16, and NKG2D in NK cells, which was reversed by human recombinant ADAM17. Furthermore, these educated NK cells could promote the viability of MDA-MB-231 or MCF-7 cells. Taken together, our results demonstrate that miR-338-3p was negatively regulated by estrogen in BC cells, impairing NK cell's activity by the up-regulation of ADAM17, and conversely promoted the viability of BC cells. Therefore, the estrogen/miR-338-3p/ADAM17 axis is critically implicated in BC pathogenesis and may provide potential targets for BC diagnosis and treatment.

Tumor-associated macrophages-derived exo-let-7a promotes osteosarcoma metastasis via targeting C15orf41 in osteosarcoma

BACKGROUND

Osteosarcoma (OS) immune environment is complexed and the immune factors-related to OS progression need to be explored. Tumor-associated macrophages (TAMs) are regarded as immune suppressive and tumor-promoting cells. However, the underlying mechanisms through which TAMs function are still fragmentary. Here, we aim to explore the underlying mechanisms by which TAMs regulate OS progression.

METHODS

TAMs from OS tissues were isolated by flow cytometry. Exosomes derived from TAMs were separated using ultracentrifugation and western blotting. Transmission electron microscopy (TEM), and flow cytometry were constructed to characterize TAMs-derived exosomes. Additionally, the differential MicroRNAs (miRNAs) and genes were detected through RNA sequencing, and further validated using real-time PCR (RT-PCR). OS cell metastasis ability was assessed using transwell invasion and scratch wound healing assays. MiRNAs mimic and lentiviral vectors were utilized to explore the effects on OS progression.

RESULTS

Exosome secreted by TAMs accelerated the OS metastasis. Let-7a level was upregulated in TAMs derived exosomes, which downregulated C15orf41 by targeting 3'-untranslated region (UTR). Furthermore, overexpressing let-7a enhanced invasion and migration by blocking the transcription of C15orf41. In consistent, up-regulating let-7a promoted OS progression and made the prognosis to be worse, which can be reversed by C15orf41 overexpression.

CONCLUSION

This study highlighted the critical role of TAMs-derived exosomes in OS progression and explored the potential value of the let-7a/C15orf41 axis as an indicator or target for OS.

Targeting CSC-related transcription factors by E3 ubiquitin ligases for cancer therapy

Evidence has revealed that transcription factors play essential roles in regulation of multiple cellular processes, including cell proliferation, metastasis, EMT, cancer stem cells and chemoresistance. Dysregulated expression levels of transcription factors contribute to tumorigenesis and malignant progression. The expression of transcription factors is tightly governed by several signaling pathways, noncoding RNAs and E3 ubiquitin ligases. Cancer stem cells (CSCs) have been validated in regulation of tumor metastasis, reoccurrence and chemoresistance in human cancer. Transcription factors have been verified to participate in regulation of CSC formation, including Oct4, SOX2, KLF4, c-Myc, Nanog, GATA, SALL4, Bmi-1, OLIG2, POU3F2 and FOX proteins. In this review article, we will describe the critical role of CSC-related transcription factors. We will further discuss which E3 ligases regulate the degradation of these CSC-related transcription factors and their underlying mechanisms. We also mentioned the functions and mechanisms of EMT-associated transcription factors such as ZEB1, ZEB2, Snail, Slug, Twist1 and Twist2. Furthermore, we highlight the therapeutic potential via targeting E3 ubiquitin ligases for modulation of these transcription factors.

Therapeutic Value of Estrogen Receptor α in Hepatocellular Carcinoma Based on Molecular Mechanisms

The incidence of hepatocellular carcinoma (HCC) is significantly lower in women than men, implying that estrogen receptors (ERs) may play an important role in this sex dimorphism. Recently, considerable progress has been made in expanding our understanding of the mechanisms of ERs in HCC. As one of the most important ERs, ERα functions as a tumor suppressor in the progression of HCC through various pathways, such as STAT3 signaling pathways, lipid metabolism-related signaling pathways, and non-coding RNAs. However, the function of ERα was reduced with the changes of some molecules in the liver, which may develop further into HCC and make it difficult to achieve an effective hormone treatment effect. Intriguingly, there are signs that individualized hormone therapy according to the activity of ERα will overcome this challenge. Based on these observations, it is particularly imperative to reassess and extend the function of ERα. In this review, we mainly elucidated molecular mechanisms associated with ERα in HCC and investigated the individualized hormone therapy based on these mechanisms, with the aim of providing new insights for HCC treatment.

ALCAP2 inhibits lung adenocarcinoma cell proliferation, migration and invasion via the ubiquitination of β-catenin by upregulating the E3 ligase NEDD4L

Lung cancer is recognized as the leading cause of cancer-related death worldwide, with non-small cell lung cancer (NSCLC) being the predominant subtype, accounting for approximately 85% of lung cancer cases. Although great efforts have been made to treat lung cancer, no proven method has been found thus far. Considering β, β-dimethyl-acryl-alkannin (ALCAP2), a natural small-molecule compound isolated from the root of Lithospermum erythrorhizon. We found that lung adenocarcinoma (LUAD) cell proliferation and metastasis can be significantly inhibited after treatment with ALCAP2 in vitro, as it can induce cell apoptosis and arrest the cell cycle. ALCAP2 also significantly suppressed the volume of tumours in mice without inducing obvious toxicity in vivo. Mechanistically, we revealed that ALCAP2-treated cells can suppress the nuclear translocation of β-catenin by upregulating the E3 ligase NEDD4L, facilitating the binding of ubiquitin to β-catenin and eventually affecting the wnt-triggered transcription of genes such as survivin, cyclin D1, and MMP9. As a result, our findings suggest that targeting the oncogene β-catenin with ALCAP2 can inhibit the proliferation and metastasis of LUAD cells, and therefore, ALCAP2 may be a new drug candidate for use in LUAD therapeutics.

ERα down-regulates carbohydrate responsive element binding protein and decreases aerobic glycolysis in liver cancer cells

Deregulated metabolism is one of the characteristics of hepatocellular carcinoma. Sex hormone receptor signalling has been involved in the marked gender dimorphism of hepatocellular carcinoma pathogenesis. Oestrogen receptor (ER) has been reported to reduce the incidence of liver cancer. However, it remains unclear how oestrogen and ER regulate metabolic alterations in liver tumour cells. Our previous work revealed that ERα interacted with carbohydrate responsive element binding protein (ChREBP), which is a transcription factor promoting aerobic glycolysis and proliferation of hepatoma cells. Here, the data showed that ERα overexpression with E2 treatment reduced aerobic glycolysis and cell proliferation of hepatoma cells. In addition to modestly down-regulating ChREBP transcription, ERα promoted ChREBP degradation. ERα co-immunoprecipitated with both ChREBP-α and ChREBP-β, the two known subtypes of ChREBP. Although E2 promoted ERα to translocate to the nucleus, it did not change subcellular localization of ChREBP. In addition to interacting with ChREBP-β and promoting its degradation, ERα decreased ChREBP-α-induced ChREBP-β transcription. Taken together, we confirmed an original role of ERα in suppressing aerobic glycolysis in liver cancer cells and elucidated the mechanism by which ERα and ChREBP-α together regulated ChREBP-β expression.

Wntless (Wls): A Prognostic Index for Progression and Patient Survival of Breast Cancer

Background

Wntless (Wls) is an essential protein that is necessary for the secretion of Wnt proteins. While numerous researches have demonstrated that aberrations in Wnt/β-catenin expression lead to tumorigenesis and progression in many cancer types, the effects of Wls in breast cancer (BC) are less studied.

Methods

The mRNA and protein expression of Wls in BC cell lines were detected by RT-qPCR and Western blot; the protein expression of patient samples was detected by immunohistochemistry (IHC). The associations between Wls expression and clinicopathological factors as well as survival time, including overall survival (OS) and disease-free survival (DFS) were analyzed. Bioinformatics analysis was used to reveal the correlation between Wls genes and associated genes or pathways.

Results

Wls was overexpressed in BC cell lines and tissues. The expression level of Wls was significantly correlated with tumor size, estrogen receptor (ER), progesterone receptor (PR), Ki-67, molecular classification, and follow-up status. Spearman correlation analysis showed that Wls protein expression was negatively correlated with ER and PR, which was confirmed by bioinformatics analysis in mRNA level. However, there were positive relationships with MBNG (modified Black's nuclear grade), tumor size, Ki-67, molecular classification, follow-up, and vital status. Univariate and multivariate analysis showed that Wls was an independent prognostic factor for OS and DFS in BC patients. Moreover, Wls was a significant prognostic indicator of OS and DFS in a hormone receptor-positive (HR+) subgroup. GSEA showed that estrogen and androgen response, as well as epithelial-mesenchymal transition pathways, were up-regulated in the Wls high-expression group.

Conclusion

Overexpression of Wls is a significant marker of worse prognosis in BC and might play a crucial role in the HR+ subgroup.

Molecular characterization of lysyl oxidase-mediated extracellular matrix remodeling during mouse decidualization

The establishment of decidualization is a prerequisite of successful pregnancy. Lysyl oxidase (Lox) is a copper-containing amine oxidase which catalyzes cross-linking of collagen and elastin in the ECM. Lox is expressed in the subluminal stroma surrounding the implanting blastocyst on day 5 of pregnancy. From days 6 to 8, the signals for Lox mRNA and protein are strongly detected in the decidual cells. The expression of Lox is under the control of estrogen via the GSK-3β/β-catenin/c-myc pathway. Dtprp is decreased by the inhibition of Lox activity. Furthermore, the inhibition of Lox activity decreases stromal cell migration and embryo adhesion. Our findings highlight the crucial role of Lox in endometrial stromal cells and deepen our understanding of decidualization.