ASAP1 activates the IQGAP1/CDC42 pathway to promote tumor progression and chemotherapy resistance in gastric cancer

ASAP1 and ARF1 Regulate Myogenic Differentiation in Rhabdomyosarcoma by Modulating TAZ Activity

Despite aggressive, multimodal therapies, the prognosis of patients with refractory or recurrent rhabdomyosarcoma (RMS) has not improved in four decades. Because RMS resembles skeletal muscle precursor cells, differentiation-inducing therapy has been proposed for patients with advanced disease. In RAS-mutant PAX fusion-negative RMS (FN-RMS) preclinical models, MEK1/2 inhibition (MEKi) induces differentiation, slows tumor growth, and extends survival. However, the response is short-lived. A better understanding of the molecular mechanisms regulating FN-RMS differentiation could improve differentiation therapy. In this study, we identified a role in FN-RMS differentiation for ASAP1, an ADP ribosylation factor (ARF) GTPase-activating protein (GAP) with both proinvasive and tumor-suppressor functions. We found that ASAP1 knockdown inhibited differentiation in FN-RMS cells. Interestingly, knockdown of the GTPases ARF1 or ARF5, targets of ASAP1 GAP activity, also blocked differentiation of FN-RMS. We discovered that loss of ARF pathway components blocked myogenic transcription factor expression. Therefore, we examined the effects on transcriptional regulators. MEKi led to the phosphorylation and inactivation of WW domain-containing transcriptional regulator 1 (WWTR1; TAZ), a homolog of the pro-proliferative transcriptional co-activator YAP1, regulated by the Hippo pathway. However, loss of ASAP1 or ARF1 blocked this inactivation, which inhibits MEKi-induced differentiation. Finally, MEKi-induced differentiation was rescued by dual knockdown of ASAP1 and WWTR1. This study shows that ASAP1 and ARF1 are necessary for myogenic differentiation, providing a deeper understanding of differentiation in FN-RMS and illuminating an opportunity to advance differentiation therapy. Implications: ASAP1 and ARF1 regulate MEKi-induced differentiation of FN-RMS cells by modulating WWTR1 (TAZ) activity, supporting YAP1/TAZ inhibition as a FN-RMS differentiation therapy strategy.

Platelet related gene IQGAP1 contributes to the onset and abnormal immune landscape of ischemic stroke patients

INTRODUCTION

Ischemic stroke (IS) is a complex illness resulting from a combination of numerous environmental and genetic risk factors. Recent reports have shed light on the vital role that platelets play in the pathophysiology of IS. Here, we aimed to explore the potential platelet-related genes in IS and investigate the effect of platelet-related genes in the immune microenvironment of IS.

METHODS

The data of IS were retrieved from the Gene Expression Omnibus database. Firstly, we screened the platelet-related genes that were correlated with the onset of IS using differential expression analysis, enrichment analyses, and protein-protein interaction (PPI) network. Moreover, we analyzed the clinical value and functional information of platelet-related genes in IS. Finally, we explored the correlation between platelet-related genes and immune cells' infiltration.

RESULTS

Ten platelet-related genes that were correlated with the onset of IS were identified, among which IQGAP1 was located at the core of the PPI network. IQGAP1 was found to be expressed in the normal brain tissue and its expression was significantly elevated in IS samples. The area under the curve (AUC) values for IQGAP1 in both the GSE16561 and GSE58294 datasets were close to 1. IQGAP1 knockdown might increase OGD/R‑induced HT22 cell viability. Additionally, FoxO signaling pathway, NOD-like receptor signaling pathway, Phagosome and Platelet activation pathways were significantly activated in IS patients with high IQGAP1 expression compared to those with low IQGAP1 expression. The IS patients in the IQGAP1high and IQGAP1low groups showed dramatically different proportions of immune cells and immune-related functions, and the IQGAP1 expression was correlated with the immune cell' infiltration in IS.

CONCLUSIONS

In this study, we identified the IQGAP1 might serve as a potential diagnostic marker for IS, and the IQGAP1 expression was very relevant in determining the immune cell' infiltration in IS patients.

ASAP1 promotes extrahepatic cholangiocarcinoma progression by regulating the Wnt/β-catenin pathway in vitro and in vivo

This study sought to identify the relationship between ADP-ribosylation factor GTPase-activating protein (ASAP1) expression and clinical outcomes in extrahepatic cholangiocarcinoma (EHCC) patients. Quantitative real-time PCR (qRT-PCR), Western blotting, and immunohistochemistry were used to analyze the expression of ASAP1 in cholangiocarcinoma (CC) tissue samples and cell lines. The survival rate and clinicopathological characteristics of CC patients were also examined. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to detect cell proliferation. Flow cytometry was used to assess the cell cycle distribution. Both in vitro and in vivo experiments showed that ASAP1 knockdown decreased cell proliferation, inhibited cell cycle progression, and increased apoptosis. ASAP1 regulates Wnt/β-catenin pathway activity in CC, promoting cell migration, and invasion in culture; and promotes tumor development in vivo. ASAP1 plays a key role in EHCC tumor development and could serve as a potential therapeutic target for EHCC.

Mitotic spindle positioning protein serves as prognostic biomarker in patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) ranks among the most aggressive types of cancer globally. Currently, clinical tumor prognostic biomarkers still lack accuracy. Mitotic spindle positioning (MISP) protein connects microtubules to the actin cytoskeleton and adhesive plaques, playing a critical role in spindle positioning, orientation, and the process of cell division. MISP can regulate the malignant biological functions of pancreatic cancer and intrahepatic cholangiocarcinoma and it acts as biomarker for prognosis, but its role in CRC remains unclear.

METHODS

This study has collected 37 CRC tissue samples and 37 corresponding adjacent nontumor tissue samples, and 57 additional CRC tissues samples. Clinical data were obtained from the patients with CRC. MISP mRNA and protein expression levels were analyzed in normal control and CRC tissues using the GEPIA and Human Protein Atlas website. MISP protein levels in the collected tissues were analyzed using immunohistochemistry.

RESULTS

MISP mRNA and protein expression levels were significantly increased in CRC tissues compared to adjacent nontumor tissues. Higher MISP protein levels were associated with distant metastasis, recurrence, and lower survival rates. Kaplan-Meier analysis showed that high expression levels of MISP protein were associated with recurrence and death in CRC patients. In addition, a high expression level of MISP protein, lymph node metastasis, and distance metastasis were risk factors for recurrence and a poor prognosis in patients with CRC.

CONCLUSION

Elevated MISP protein correlated with tumor metastasis, recurrence, and lower survival rates in patients with CRC, and thus, MISP has the potential to become a prognostic marker for CRC.

High-yield nanovesicles extruded from dental follicle stem cells promote the regeneration of periodontal tissues as an alternative of exosomes

AIM

To identify an optimized strategy for the large-scale production of nanovesicles (NVs) that preserve the biological properties of exosomes (EXOs) for use in periodontal regeneration.

MATERIALS AND METHODS

NVs from dental follicle stem cells (DFSCs) were prepared through extrusion, and EXOs from DFSCs were isolated. The yield of both extruded NVs (eNVs) and EXOs were quantified through protein concentration and particle number analyses. Their pro-migration, pro-proliferation and pro-osteogenesis capacities were compared subsequently in vitro. Additionally, proteomics analysis was conducted. To further evaluate the periodontal regeneration potential of eNVs and EXOs, they were incorporated into collagen sponges and transplanted into periodontal defects in rats. In vivo imaging and H&E staining were utilized to verify their biodistribution and safety. Micro-Computed Tomography analysis and histological staining were performed to examine the regeneration of periodontal tissues.

RESULTS

The yield of eNVs was nearly 40 times higher than that of EXOs. Interestingly, in vitro experiments indicated that the pro-migration and pro-proliferation abilities of eNVs were superior, and the pro-osteogenesis potential was comparable to EXOs. More importantly, eNVs exhibited periodontal regenerative potential similar to that of EXOs.

CONCLUSIONS

Extrusion has proven to be an efficient method for generating numerous eNVs with the potential to replace EXOs in periodontal regeneration.

CUL1 exacerbates glucocorticoid-induced osteoporosis by enhancing ASAP1 ubiquitination

BACKGROUND

Glucocorticoid-induced osteoporosis is a leading secondary cause of osteoporosis. Cullin-1 (CUL1) levels are abnormally elevated in patients with osteoporosis, but the underlying mechanism remains unclear. The purpose of this study was to elucidate the mechanism of action of CUL1 in a glucocorticoid (dexamethasone, Dex)-induced osteoporosis model.

METHODS

C57BL/6J mice were intraperitoneally injected with Dex to establish an osteoporosis model. Mouse femur bone injury and bone formation were detected using hematoxylin-eosin or Masson staining. Apoptosis and cell cycle distribution were determined by flow cytometry. Alkaline phosphatase (ALP) activity and calcified nodules were monitored using ALP and Alizarin Red S staining. The molecular mechanism was validated by co-immunoprecipitation (Co-IP) and ubiquitination assays.

RESULTS

CUL1 expression was enhanced in the Dex-induced osteoporosis mouse model. CUL1 silencing moderated the Dex-induced cell proliferation and osteogenesis inhibition. Moreover, CUL1 promoted the ubiquitination and degradation of ASAP1 via the SKP1-CUL1-F-box (SCF)-FBXW7 complex. CUL1 induced apoptosis and repressed osteogenesis by ASAP1. CUL1 silencing alleviated the Dex-induced osteoporosis in mice.

CONCLUSION

CUL1 suppressed osteoblast proliferation and osteogenesis by promoting ASAP1 ubiquitination via the SCF-FBXW7 complex in glucocorticoid-induced osteoporosis.

Inhibition of ASAP1 Modulates the Tumor Immune Microenvironment and Suppresses Lung Cancer Metastasis via the p-STAT3 Signaling Pathway

ADP ribosylation factor guanylate kinase 1 (ASAP1), a key protein regulating cell migration and invasion, has attracted extensive attention in oncological research in recent years. This study aims to explore the effects of ASAP1 inhibition on lung cancer metastasis and its potential mechanisms, particularly how it modulates the tumor immune microenvironment through the p-STAT3 signaling pathway. In this study, shRNA technology was employed to specifically inhibit ASAP1 expression in lung cancer cell lines A549, NCI-H1299, and PC-9. The effects of ASAP1 inhibition on lung cancer cell viability, apoptosis, migration, and invasion were evaluated using CCK-8, TUNEL apoptosis detection, and cell migration and invasion assays. Furthermore, animal experiments were conducted to assess the in vivo effects of ASAP1 inhibition on lung cancer metastasis, and immunohistochemical analysis was performed to investigate changes in immune cells in lung metastasis models, further exploring its impact on the tumor immune microenvironment. The experimental results demonstrated that ASAP1 inhibition significantly reduced lung cancer cell viability, induced apoptosis in A549, NCI-H1299, and PC-9 cells, and suppressed the migration and invasion abilities of these cells. In vivo experiments revealed that ASAP1 inhibition effectively suppressed lung cancer metastasis and altered the tumor immune microenvironment by regulating immune cells. Moreover, we found that ASAP1 inhibition could decrease tumor cell proliferation and induce tumor apoptosis in lung metastasis models by inhibiting the p-STAT3 signaling pathway. This study confirms that ASAP1 inhibition can suppress lung cancer metastasis by modulating the tumor immune microenvironment through the inhibition of the p-STAT3 signaling pathway. These findings provide new targets for lung cancer treatment and a theoretical basis for developing novel strategies against lung cancer metastasis. Future research will further explore the mechanisms of ASAP1 in lung cancer metastasis and how to optimize treatment strategies for lung cancer patients by targeting ASAP1.

NSUN4 mediated RNA 5-methylcytosine promotes the malignant progression of glioma through improving the CDC42 mRNA stabilization

5-Methylcytosine (m5C) methylation is a significant post-transcriptional modification that play a crucial role in the development and progression of numerous cancers. Whereas the functions and molecular mechanisms underlying m5C methylation in gliomas remain unclear. This study dedicated to explore changes of m5C levels and the clinical significance of the m5C writer NSUN4 in gliomas. We found that high m5C levels were negatively related to prognosis of patients with glioma. Moreover, gain- and loss-of-function experiments revealed the role of NSUN4 in enhancing m5C modification of mRNA to promote the malignant progression of glioma. Mechanistically speaking, NSUN4-mediated m5C alterations regulated ALYREF binding to CDC42 mRNA, thereby impacting the mRNA stability of CDC42. We also demonstrated that CDC42 promoted glioma proliferation, migration, and invasion by activating the PI3K-AKT pathway. Additionally, rescue experiments proved that CDC42 overexpression weaken the inhibitory effect of NSUN4 knockdown on the malignant progression of gliomas in vitro and in vivo. Our findings elucidated that NSUN4-mediated high m5C levels promote ALYREF binding to CDC42 mRNA and regulate its stability, thereby driving the malignant progression of glioma. This provides theoretical support for targeted the treatment of gliomas.

Role of ADP ribosylation factor guanylate kinase 1 in the malignant biological behavior of gastric cancer

Aim

This study aims to investigate the influence of ASAP1 (ADP ribosylation factor guanylate kinase 1) on the malignant behavior of gastric cancer (GC) cells and to elucidate the potential molecular mechanisms involved in cancer development and progression.

Methods

We assessed the impact of ASAP1 overexpression and knockdown on GC cell malignancy using CCK8, colony formation, flow cytometry (Annexin V/propidium iodide), Transwell migration, invasion, and scratch assays. Western blot analysis was used to assess the effects of ASAP1 on angiogenesis, matrix metalloproteinases (MMPs), apoptotic proteins, epithelial-mesenchymal transition (EMT)-related proteins, as well as AKT and p-AKT. The influence of ASAP1 knockdown was also evaluated in nude mice bearing BGC823 cell-derived tumors.

Results

Our findings revealed that ASAP1 was significantly overexpressed in GC cells, enhancing their proliferation, invasion, and migration, while reducing apoptosis. Conversely, ASAP1 knockdown reversed these effects, markedly increasing the expression of cleaved-caspase 3 (Casp3), PARP, and the epithelial marker E-cadherin, and significantly decreasing MMP2, MMP9, VEGFA, and mesenchymal markers such as N-cadherin and vimentin. Additionally, it reduced AKT, and p-AKT levels (P < 0.01). Tumor growth in nude mice was suppressed following ASAP1 knockdown.

Conclusion

The overexpression of ASAP1 significantly promotes malignant behaviors in GC cells, whereas its knockdown diminishes these effects. This modulation is potentially through the downregulation of VEGFA, leading to reduced angiogenesis, Cleaved-Casp3 and Cleaved-PARP overexpression, and a decrease in MMPs, EMT, AKT, and p-AKT activity.

Deciphering drug resistance in gastric cancer: Potential mechanisms and future perspectives

Gastric cancer (GC) is a malignant tumor that originates from the epithelium of the gastric mucosa. The latest global cancer statistics show that GC ranks fifth in incidence and fourth in mortality among all cancers, posing a serious threat to public health. While early-stage GC is primarily treated through surgery, chemotherapy is the frontline option for advanced cases. Currently, commonly used chemotherapy regimens include FOLFOX (oxaliplatin + leucovorin + 5-fluorouracil) and XELOX (oxaliplatin + capecitabine). However, with the widespread use of chemotherapy, an increasing number of cases of drug resistance have emerged. This article primarily explores the potential mechanisms of chemotherapy resistance in GC patients from five perspectives: cell death, tumor microenvironment, non-coding RNA, epigenetics, and epithelial-mesenchymal transition. Additionally, it proposes feasibility strategies to overcome drug resistance from four angles: cancer stem cells, tumor microenvironment, natural products, and combined therapy. The hope is that this article will provide guidance for researchers in the field and bring hope to more GC patients.

TMEM65 promotes gastric tumorigenesis by targeting YWHAZ to activate PI3K-Akt-mTOR pathway and is a therapeutic target

Copy number alterations are crucial for the development of gastric cancer (GC). Here, we identified Transmembrane Protein 65 (TMEM65) amplification by genomic hybridization microarray to profile copy-number variations in GC. TMEM65 mRNA level was significantly up-regulated in GC compared to adjacent normal tissues, and was positively associated with TMEM65 amplification. High TMEM65 expression or DNA copy number predicts poor prognosis (P < 0.05) in GC. Furtherly, GC patients with TMEM65 amplification (n = 129) or overexpression (n = 78) significantly associated with shortened survival. Ectopic expression of TMEM65 significantly promoted cell proliferation, cell cycle progression and cell migration/invasion ability, but inhibited apoptosis (all P < 0.05). Conversely, silencing of TMEM65 in GC cells showed opposite abilities on cell function in vitro and suppressed tumor growth and lung metastasis in vivo (all P < 0.01). Moreover, TMEM65 depletion by VNP-encapsulated TMEM65-siRNA significantly suppressed tumor growth in subcutaneous xenograft model. Mechanistically, TMEM65 exerted oncogenic effects through activating PI3K-Akt-mTOR signaling pathway, as evidenced of increased expression of key regulators (p-Akt, p-GSK-3β, p-mTOR) by Western blot. YWHAZ (Tyrosine 3-Monooxygenase/Tryptophan 5-Monooxygenase) was identified as a direct downstream effector of TMEM65. Direct binding of TMEM65 with YWHAZ in the cytoplasm inhibited ubiquitin-mediated degradation of YWHAZ. Moreover, oncogenic effect of TMEM65 was partly dependent on YWHAZ. In conclusion, TMEM65 promotes gastric tumorigenesis by activating PI3K-Akt-mTOR signaling via cooperating with YWHAZ. TMEM65 overexpression may serve as an independent new biomarker and is a therapeutic target in GC.

miR-1204 Positioning in 8q24.21 Involved in the Tumorigenesis of Colorectal Cancer by Targeting MASPIN

BACKGROUND

Colorectal cancer remains to be the third leading cause of cancer mortality rates. Despite the diverse effects of the miRNA cluster located in PVT1 of 8q24.21 across various tumors, the specific biological function in colorectal cancer has not been clarified.

METHODS

The amplification of the miR-1204 cluster was analyzed with the cBioPortal database, while the expression and survival analysis of the miRNAs in the cluster were obtained from several GEO databases of colorectal cancer. To investigate the functional role of miR-1204 in colorectal cancer, overexpression and silencing experiments were performed by miR-1204 mimic and inhibitor transfection in colorectal cancer cell lines, respectively. Then, the effects of miR-1204 on cell proliferation were assessed through CCK-8, colony formation, and Edu assay. In addition, cell migration was evaluated using wound healing and Transwell assay. Moreover, candidate genes identified through RNA sequencing and predicted databases were identified and validated using PCR and western blot. A Dual-luciferase reporter experiment was conducted to identify MASPIN as the target gene of miR-1204.

RESULTS

In colorectal cancer, the miR-1204 cluster exhibited high amplification, and the expression levels of several cluster miRNAs were also significantly increased. Furthermore, miR-1204 was found to be significantly associated with disease-specific survival according to the analysis of GSE17536. Functional experiments demonstrated that transfection of miR-1204 mimic or inhibitor could enhance or decrease cancer cell proliferation and migration. MASPIN was identified as a target of miR-1204. Additionally, the overexpression of MASPIN partially rescued the effect of miR-1204 mimics on tumorigenic abilities in LOVO cells.

CONCLUSION

miR-1204 positioning in 8q24.21 promotes the proliferation and migration of colorectal cancer cells by targeting MASPIN.

Cell division cycle 42 effector protein 4 inhibits prostate cancer progression by suppressing ERK signaling pathway

Prostate cancer (PCa) is the most common malignancy among men worldwide. The cell division cycle 42 effector protein 4 (CDC42EP4) functions downstream of CDC42, yet its role and molecular mechanisms in PCa remain unexplored. This study aimed to elucidate the role of CDC42EP4 in the progression of PCa and its underlying mechanisms. Bioinformatical analysis indicated that CDC42EP4 expression was significantly lower in PCa tissue compared to normal prostate tissue. Cellular phenotyping analysis suggested that CDC42EP4 markedly inhibited the proliferation, migration, and invasion of PCa cells. Xenograft tumor assays further demonstrated that CDC42EP4 suppressed the growth of PCa cells in vivo. Mechanistically, the study established that CDC42EP4 inhibited the ERK pathway in PCa cells. Additionally, the ERK pathway inhibitor PD0325901 was employed, revealing that PD0325901 significantly nullified the effects of CDC42EP4 on PCa cell proliferation, migration, and invasion. Collectively, our findings demonstrate that CDC42EP4 acts as a critical tumor suppressor gene, inhibiting PCa cell proliferation, migration, and invasion through the ERK pathway, thereby presenting potential targets for PCa therapy.

Integrated immunological analysis of single-cell and bulky tissue transcriptomes reveals the role of interactions between M0 macrophages and naïve CD4+ T cells in the immunosuppressive microenvironment of cervical cancer

In recent decades, the incidence and mortality of cervical cancer have declined in developed countries due to the implementation of screening and vaccination programs. However, cervical cancer remains one of the major culprits of cancer-related deaths in young women. Current studies have found that immune cell-related intercellular communication in the tumor microenvironment has a large impact on the construction of the immunosuppressive microenvironment. In this study, we performed a comprehensive immune analysis on bulk RNA-seq and scRNA-seq data obtained from cervical cancer and revealed that two highly plastic cell populations, M0 macrophages and naïve CD4+ T cells, were significantly correlated with prognosis and clinical phenotypes. Notably, signaling between M0 macrophages and naïve CD4+ T cells as well as intracellular transcription factor activity were significantly altered in the tumor state. Furthermore, we identified overlapping genes between the transcription factor target genes of M0 macrophages or naïve CD4+ T cells and the differentially expressed genes in each type of cell, and these overlapping genes were subsequently subjected to an analysis using the LASSO regression model. Finally, we generated a score index that was significantly associated with the clinical prognosis of cervical cancer. In conclusion, interventions to improve the communication between M0 macrophages and naïve CD4+ T cells may help to improve the immunosuppressive microenvironment of cervical cancer and prevent immune evasion. The relevant molecular mechanisms need to be further validated by experimental and cohort studies.