ADA3 regulates normal and tumor mammary epithelial cell proliferation through c-MYC

A gel plaster in the form of nipple cover: A comfortable and safe transdermal delivery method for mammary hyperplasia

Hyperplasia of mammary glands (HMG) is considered a precancerous condition with a risk of malignant transformation, highlighting the necessity of proactive treatment in the early stages. Transdermal drug delivery offers significant advantages such as painlessness, absence of first-pass effect, and good patient compliance. However, the unique structure of the breast requires transdermal formulations for treating mammary hyperplasia to exhibit higher levels of safety and comfort. We have formulated an ancient topical formula called 'Muxiang Bing,' comprising traditional Chinese medicines Aucklandiae Radix (AR) and Rehmanniae Radix (RR), for the treatment of HMG. This formula has been transformed into a gel paster in the form of nipple cover for trans-nipple-areola delivery. In our investigations, we observed that the optimal formulation of the Muxiang gel plaster demonstrated enhanced permeation facilitated by AR's effect on RR. Furthermore, pre-treatment with the Muxiang gel plaster improved mammary tissue morphology, hormone levels, oxidative stress, aberrant cell proliferation, and damage in rat models, thus preventing and ameliorating mammary hyperplasia. The Muxiang gel plaster exhibited low skin irritability in rats, and long-term use did not cause harm to their internal organs or blood cells, indicating its safety and efficacy.

RBM15 m6 A modification-mediated OTUB2 upregulation promotes cervical cancer progression via the AKT/mTOR signaling

Cervical cancer (CC) is a deadly gynecological tumor worldwide. Otubain 2 (OTUB2) has been recently identified as an oncogene in human malignancies. However, its expression and function remain unclear. This work aims to explore the role of OTUB2 in CC progression. Herein, The Cancer Genome Atlas data revealed that OTUB2 expression was significantly upregulated in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) and gradually increased with CESC progression; moreover, OTUB2 expression predicted poor outcomes of CESC patients. Then, RT-qPCR and Western blotting were applied to determine mRNA and protein expression in CC and normal cells. Our results confirmed that OTUB2 was highly expressed in CC cell lines. As indicated by CCK-8, Transwell, and flow cytometry results, OTUB2 silencing attenuated proliferative and metastatic capacities of CC cells but promoted CC cell apoptosis. Then, RBM15, an N6-methyladenosine (m6 A) methyltransferase "writer," was also demonstrated to be upregulated in CESC and CC cells. Mechanistically, m6 A RNA immunoprecipitation (Me-RIP) results showed that RBM15 inhibition reduced the m6 A methylation level of OTUB2 in CC cells, leading to the decline of OTUB2 expression. In addition, OTUB2 inhibition deactivated the AKT/mTOR signaling in CC cells. Furthermore, SC-79 (AKT/mTOR activator) partially abated the inhibitory effects of OTUB2 knockdown on the AKT/mTOR signaling pathway and the malignant phenotypes of CC cells. In summary, this work showed that RBM15-mediated m6 A modification led to OTUB2 upregulation, thereby promoting malignant behaviors of CC cells via the AKT/mTOR signaling pathway.

Conservation and diversity of the eukaryotic SAGA coactivator complex across kingdoms

The SAGA complex is an evolutionarily conserved transcriptional coactivator that regulates gene expression through its histone acetyltransferase and deubiquitylase activities, recognition of specific histone modifications, and interactions with transcription factors. Multiple lines of evidence indicate the existence of distinct variants of SAGA among organisms as well as within a species, permitting diverse functions to dynamically regulate cellular pathways. Our co-expression analysis of genes encoding human SAGA components showed enrichment in reproductive organs, brain tissues and the skeletal muscle, which corresponds to their established roles in developmental programs, emerging roles in neurodegenerative diseases, and understudied functions in specific cell types. SAGA subunits modulate growth, development and response to various stresses from yeast to plants and metazoans. In metazoans, SAGA further participates in the regulation of differentiation and maturation of both innate and adaptive immune cells, and is associated with initiation and progression of diseases including a broad range of cancers. The evolutionary conservation of SAGA highlights its indispensable role in eukaryotic life, thus deciphering the mechanisms of action of SAGA is key to understanding fundamental biological processes throughout evolution. To illuminate the diversity and conservation of this essential complex, here we discuss variations in composition, essentiality and co-expression of component genes, and its prominent functions across Fungi, Plantae and Animalia kingdoms.

Complex functions of Gcn5 and Pcaf in development and disease

A wealth of biochemical and cellular data, accumulated over several years by multiple groups, has provided a great degree of insight into the molecular mechanisms of actions of GCN5 and PCAF in gene activation. Studies of these lysine acetyltransferases (KATs) in vitro, in cultured cells, have revealed general mechanisms for their recruitment by sequence-specific binding factors and their molecular functions as transcriptional co-activators. Genetic studies indicate that GCN5 and PCAF are involved in multiple developmental processes in vertebrates, yet our understanding of their molecular functions in these contexts remains somewhat rudimentary. Understanding the functions of GCN5/PCAF in developmental processes provides clues to the roles of these KATs in disease states. Here we will review what is currently known about the developmental roles of GCN5 and PCAF, as well as emerging role of these KATs in oncogenesis.

CCL14 serves as a novel prognostic factor and tumor suppressor of HCC by modulating cell cycle and promoting apoptosis

CCL14 is a member of CC chemokines and its role in hepatocellular carcinoma (HCC) is still unknown. In this study, CCL14 expression were analyzed by tissue microarray (TMA) including 171 paired tumor and peritumor tissues of patients from Zhongshan Hospital of Fudan University. We found for the first time that CCL14 was downregulated in HCC tumor tissues compared with peritumor tissues (P = 0.01). Meanwhile, CCL14 low expression in HCC tumor tissues is associated with a poor prognosis (P = 0.035). CCL14 also displayed its predictive value in high differentiation (P = 0.026), liver cirrhosis (P = 0.003), and no tumor capsule (P = 0.024) subgroups. The underlying mechanisms were further investigated in HCC cell lines by CCL14 overexpression and knock-down in vitro. We found overexpression of CCL14 suppressed proliferation and promoted apoptosis of HCC cells. Finally, the effect was confirmed by animal xenograft tumor models in vivo. The results shown overexpression of CCL14 lead to inhibiting the growth of tumor in nude mice. Interestingly, our data also implied that CCL14 played these effects by inhibiting the activation of Wnt/β-catenin pathway. These findings suggest CCL14 is a novel prognostic factor of HCC and serve as a tumor suppressor.

A miR-567-PIK3AP1-PI3K/AKT-c-Myc feedback loop regulates tumour growth and chemoresistance in gastric cancer

Background

Gastric cancer (GC) ranks the fifth most common cancer, and chemotherapy is one of the most common treatments for GC. However, chemoresistance limits the effectiveness of chemotherapy and leads to treatment failure. This study aims to investigate the biological effect of miR-567 on gastric tumourigenesis and chemoresistance and reveal the possible mechanism.

Methods

We measured the expression of miR-567 in 37 paired normal and stomach tumour specimens, as well as GC cell lines by Real-time PCR. The functional effects of miR-567 were validated using in vitro and in vivo assays. Dual-luciferase report assays and Chromatin immunoprecipitation (ChIP) assay were conducted for target evaluation, western blot assay was used to confirm the relationships.

Findings

Our data showed that miR-567 was downregulated in gastric tissues and gastric cancer cells compared with normal tissues and gastric epithelial cells. In vitro, Gain- and lose-of-function assays showed miR-567 not only weakened cells proliferative ability, but also sensitized GC cells to 5-FU and oxaliplatin. In vivo, miR-567 overexpression significantly repressed the tumourigenesis of GC cells compared with the vector control. Mechanistic analysis showed that PIK3AP1 activated AKT phosphorylation in GC. Meanwhile, miR-567 directly targeted PIK3AP1 to inactivate PI3K/AKT/c-Myc pathway and c-Myc inversely regulated miR-567 expression, thus forming a miR-567-PIK3AP1- PI3K/AKT-c-Myc feedback loop explaining the function of miR-567.

Interpretation

Our studies revealed that miR-567 acts as a tumour suppressor gene and suppresses GC tumorigenesis and chemoresistance via a miR-567-PIK3AP1- PI3K/AKT-c-Myc feedback loop. These results suggest that miR-567 may serve as a target for chemoresistance and a potential prognostic biomarker for GC.

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miR-567 sensitized GC cells to 5-FU and oxaliplatin, suggesting that it can be a target for chemoresistance.

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miR-567 functions as a suppressor in GC progression and may serve as a novel prognostic and therapeutic biomarker for GC.

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miR-567 directly targeted PIK3AP1 to inactivate PI3K/AKT/c-Myc and regulated its own expression.

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These findings uncover a plausible mechanism for AKT/PI3K signalling activation in cancer progression.

Overexpression of Alteration/Deficiency in Activation 3 correlates with poor prognosis in non-small cell lung cancer

Alteration/Deficiency in Activation 3 (ADA3), the human homologue of yeast ADA3, is involved in a variety of cell biological processes and plays an important role in tumorigenesis. Here, western blotting and reverse-transcription quantitative PCR (RT-qPCR) were conducted to explore the expression pattern of ADA3 in non-small cell lung cancer (NSCLC) patients. It was found that ADA3 protein expression in cancerous tissues was significantly higher than that in adjacent normal lung tissues, but there were no differences in mRNA levels. Tissue microarray immunohistochemical assay (TMA-IHC) was performed and we investigated the prognostic significance of ADA3 expression in 84 cases of NSCLC. Survival analyses showed that high expression of ADA3 was an independent prognostic factor for unfavorable overall survival (OS) in patients with NSCLC. In summary, the ADA3 expression level elevates in NSCLC and correlates with poor OS in NSCLC patients.

3D hydrogel breast cancer models for studying the effects of hypoxia on epithelial to mesenchymal transition

Solid tumors are 3D assemblies of cancer cells, together with multiple stromal cell types within an extracellular matrix. Yet, the vast majority of cell-based studies to characterize oncogenesis and discovery of new anti-cancer drugs is conducted using conventional 2D monolayer culture systems, where cells are grown on plastic substratum under normoxic environments. In current study, we generated 3D breast cancer cell culture platform consists of photocrosslinkable hydrogels and encapsulated isogenic primary (21PT) and a metastatic (21MT-2) breast cancer cell lines derived from the primary tumor and pleural effusion from the same patient. We demonstrated that hypoxia decreased cellular assembly size and density, and promoted epithelial to mesenchymal transition (EMT) process, without affecting cell viability. Next, we showed hypoxia enhanced breast cancer cell migration, and expression and secretion of lysyl oxidase (LOX), which is copper-dependent amine oxidase and has the primary function to drive the crosslinking of collagen and elastin and is regulated by hypoxia. Furthermore, to recapitulate in vivo situation, we generated breast cancer and lung cells (derived from the same patient) contact model by stacking 3D hydrogel constructs with breast cancer cells onto lung mesenchymal cells (LMC) laden-hydrogel and then showed breast cancer cells migrated towards LMC during hypoxia. Lastly, as a validation of this model for future screen of therapeutic agents, we demonstrated that LOX inhibitor exhibited a significant decrease in breast cancer cell viability, migration, and EMT. Taken together, these results validate the use of hydrogels based models to examine hypoxia related EMT in breast cancer cells.

Epidermal Growth Factor Receptor activation promotes ADA3 acetylation through the AKT-p300 pathway

The ADA3 (Alteration/Deficiency in Activation 3) protein is an essential adaptor component of several Lysine Acetyltransferase (KAT) complexes involved in chromatin modifications. Previously, we and others have demonstrated a crucial role of ADA3 in cell cycle progression and in maintenance of genomic stability. Recently, we have shown that acetylation of ADA3 is key to its role in cell cycle progression. Here, we demonstrate that AKT activation downstream of Epidermal Growth Factor Receptor (EGFR) family proteins stimulation leads to phosphorylation of p300, which in turn promotes the acetylation of ADA3. Inhibition of upstream receptor tyrosine kinases (RTKs), HER1 (EGFR)/HER2 by lapatinib and the accompanying reduction of phospho-AKT levels led to a decrease in p300 phosphorylation and ADA3 protein levels. The p300/PCAF inhibitor garcinol also destabilized the ADA3 protein in a proteasome-dependent manner and an ADA3 mutant with K→R mutations exhibited a marked increase in half-life, consistent with opposite role of acetylation and ubiquitination of ADA3 on shared lysine residues. ADA3 knockdown led to cell cycle inhibitory effects, as well as apoptosis similar to those induced by lapatinib treatment of HER2+ breast cancer cells, as seen by accumulation of CDK inhibitor p27, reduction in mitotic marker pH3(S10), and a decrease in the S-phase marker PCNA, as well as the appearance of cleaved PARP. Taken together our results reveal a novel RTK-AKT-p300-ADA3 signaling pathway involved in growth factor-induced cell cycle progression.