BCAP31 is involved in modulating colorectal cancer cell proliferation via the Emerin/ß-catenin axis.

Understanding the mechanisms of colorectal cancer (CRC) progression is critical for developing innovative treatment strategies. As an endoplasmic reticulum-located protein, B cell receptor-associated protein 31 (BCAP31) has been identified to be highly expressed in multiple cancers. However, its function and molecular mechanism in CRC remain not fully understood. In the present study, BCAP31 expression and its correlation with the clinical stage were analyzed based on TCGA database. We demonstrated that loss of BCAP31 suppressed CRC cell proliferation in vitro and tumor growth in vivo. Mechanistically, we demonstrated that Emerin was an interaction partner and downstream molecule of BCAP31. Knockdown of BCAP31 promoted the nuclear envelope localization of Emerin, leading to a reduction of ß-catenin accumulation in the nucleus, which resulted in downregulation of Wnt/ß-catenin downstream target genes, including c-Myc, cyclin D1, Survivin, and Mcl-1. Moreover, downregulation of Emerin partially restored the BCAP31 depletion-mediated ß-catenin protein level and tumor suppressive effects in CRC cells.Our data highlights the pivotal role of BCAP31 depletion in inhibiting cell proliferation in CRC cells, and mechanistically via Emerin/ß-catenin signaling, which may serve as a promising target for CRC treatment.

SND1 acts as a functional target of miR-330-5p involved in modulating the proliferation, apoptosis and invasion of colorectal cancer cells.

MicroRNAs (miRNAs) play a crucial role in cancer progression due to their capability to modulate the expression of various target genes. However, given the heterogeneity of tumor cells, miRNAs have been confirmed to exert different regulatory effects. Here, bioinformatic analysis results indicated that expression of miR-330-5p is decreased in colorectal cancer (CRC) tissues and inversely correlated with SND1 expression. Notably, ectopic expression of miR-330-5p restrained tumor cell proliferation, migration, and enhance the sensitivity of CRC cells to 5-FU. Moreover, similar phenotypes were substantiated after inhibition of SND1 expression using RNA interference. Conversely, overexpression of SND1 facilitated the malignant phenotypes of CRC cells and restored miR-330-5p-mediated tumor-suppressive activities in CRC cells. Mechanistically, miR-330-5p directly binds to SND1-3'-untranslated region (3'-UTR), thus involving in inhibiting CRC cells proliferation and invasion and promoting apoptosis. Taken together, miR-330-5p may act as a tumor suppressor by targeting the expression of SND1, suggesting that the miR-330-5p/SND1 axis may be a meaningful regulator for CRC intervention.

TRX2/Rab35 Interaction Impairs Exosome Secretion by Inducing Rab35 Degradation.

Given that exosomes mediate intercellular communication by delivering cellular components to recipient cells or tissue, they have the potential to be engineered to deliver therapeutic payloads. However, the regulatory mechanism of exosome secretion is poorly understood. In addition, mitochondrial components have been found in exosomes, suggesting communication between mitochondria and exosomes. However, the molecular mechanism of the mitochondria and vesicle interaction remains unclear. Here, we showed that mitochondrial thioredoxin 2 (TRX2) decreased exosome concentrations and inhibited HCT116 cell migration. Coimmunoprecipitation/mass spectrometry (Co-IP/MS) showed that TRX2 interacted with Rab35. TRX2 and Rab35 bound to each other at their N-terminal motifs and colocalized on mitochondria. Furthermore, TRX2 induced Rab35 degradation, resulting in impaired exosome secretion. Additionally, Rab35 mediated the suppressive effects of TRX2 on cell migration, and TRX2 suppressed cell migration through exosomes. Taken together, this study first found an interaction between TRX2 and Rab35. These results revealed a new role for TRX2 in the regulation of exosome secretion and cell migration and explained the upstream regulatory mechanism of Rab35. Furthermore, these findings also provide new molecular evidence for communication between mitochondria and vesicles.

PARD6A promotes lung adenocarcinoma cell proliferation and invasion through Serpina3.

Par6α encoded by PARD6A is a member of the PAR6 family and is reported to promote cancer initiation and progression. PARD6A is frequently upregulated in different types of cancers, but its regulatory role in lung cancer progression is yet to be established. In this study, we analyzed the PARD6A expression in biopsies from lung adenocarcinoma (LUAD) patients, and the survival probability using LUAD tissue microarray (TMA) and online datasets from TCGA and GEO. We conducted in vitro and in vivo assays to assess the role of PARD6A in regulating lung cancer progression, including proliferation, wound healing, transwell, RNA-seq, and subcutaneous tumor mice models. Our findings revealed that PARD6A is highly expressed in cancer tissues from LUAD patients and is associated with poor prognosis in LUAD patients. In vitro assays showed that PARD6A promoted cell proliferation, migration, and invasion. The transcriptome sequencing identified Serpina3 as one of the key downstream molecules of PARD6A. Ectopic expression of Serpina3 rescued impaired proliferation, migration, and invasion in PARD6A-knocking down H1299 cells, whereas silencing Serpina3 impeded enhanced proliferation, migration, and invasion in PARD6A-overexpressing H1975 cells. Our findings suggest that PARD6A promotes lung cancer progression by inducing Serpina3, which may be a promising therapeutic target.

miR-653-3p promotes genomic instability of colorectal cancer cells via targeting SIRT1/TWIST1 signaling pathway.

Development of colorectal cancer (CRC) accompanied with genomic instability. Genomic instability was promoted by microRNAs (miRNAs) inhibiting key genes in DNA damage repair and spindle assembly processes. Whether miR-653-3p affects genomic instability is unknown. The aim of this study is to explore the effect of miR-653-3p on genomic instability in CRC cells. Based on RT-qPCR analysis, miR-653-3p was highly expressed in CRC cells. Through single-cell electrophoresis assay and chromosome karyotype analysis, we determined ectopic expression of miR-653-3p induced increased DNA damage but inhibited apoptosis by promoting chromosomal instability. Mechanistically, luciferase assay identified the direct interaction of miR-653-3p with the 3' UTR of SIRT1, and western blot analysis indicated miR-653-3p inhibited SIRT1 and then promoted STAT3 phosphorylation and TWIST1 expression. The results of karyotype analysis showed that the upregulation of SIRT1 and the downregulation of TWIST1 caused by the downregulation of miR-653-3p suppressed chromosomal instability. Additionally, our evidence showed that miR-653-3p promoted CRC cell proliferation, migration, and 5-FU resistance, and miR-653-3p induced the development of CRC in the xenograft mice model. Altogether, our evidence suggests that miR-653-3p regulates SIRT1/TWIST1 signaling pathway and plays an important role in promoting genomic instability, proliferation, migration, and chemoresistance of CRC cells, which may serve as a promising therapeutic target for CRC therapy.

miR-15a-5p enhances the malignant phenotypes of colorectal cancer cells through the STAT3/TWIST1 and PTEN/AKT signaling pathways by targeting SIRT4.

Colorectal cancer (CRC) continues to represent one of the major causes of cancer-related mortality and morbidity. MicroRNAs (miRNAs) are confirmed to be involved in modulating substential biological processes by affecting the expression of targeted genes, including carcinogenesis. In the present study, the expression pattern and functional roles of microRNA-15a-5p (miR-15a-5p) in CRC cells were investigated. The data from TCGA database indicated that miR-15a-5p is highly expressed in CRC tissues. Moreover, ectopic expression of miR-15a-5p facilitated the proliferation, migration, and invasion of CRC cells. Furthermore, bioinformatic analysis combinating with dual-luciferase assay revealed that SIRT4 acts as a crucial target of miR-15a-5p. Accordingly, overexpression of SIRT4 suppresses the miR-15a-5p-mediated enhancement in the proliferation, migration, and invasion of CRC cells, while the opposite phenotypes were observed after inhibition of SIRT4. Moreover, we further revealed that miR-15a-5p restrained the expression of SIRT4 to exacerbate the malignant phenotypes by modulating STAT3/TWIST1 and PETN/AKT signaling in CRC cells. Alternatively, inhibition of the miR-15a-5p/SIRT4 axis enhanced the chemosensitivity of 5-fluorouracil- and oxaliplatin-resistant HCT116 cells. Altogether, our evidence suggests that miR-15a-5p plays an essential role in promoting the proliferation, migration, and chemoresistance of CRC cells via targeting SIRT4 to modulate STAT3/TWIST1 and PETN/AKT signaling, which may serve as a promising therapeutic target for CRC therapy.

Pre-Administration of Berberine Exerts Chemopreventive Effects in AOM/DSS-Induced Colitis-Associated Carcinogenesis Mice via Modulating Inflammation and Intestinal Microbiota.

Inflammatory activation and intestinal flora imbalance play an essential role in the development and progression of colorectal cancer (CRC). Berberine (BBR) has attracted great attention in recent years due to its heath-related benefits in inflammatory disorders and tumors, but the intricate mechanisms have not been fully elucidated. In this study, the effects and the mechanism of BBR on colon cancer were investigated in an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colitis-associated carcinogenesis mice model. Our results showed that pre-administration of BBR showed a decrease in weight loss, disease activity index (DAI) score, and the number of colon tumors in mice, compared with the model group. The evidence from pathological examination indicated that the malignancy of intestinal tumors was ameliorated after pre-administration of BBR. Additionally, pre-administration with BBR suppressed the expression of pro-inflammatory factors (interleukin (IL)-6, IL-1ß, cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)-α) and the cell-proliferation marker Ki67, while expression of the tight junction proteins (ZO-1 and occludin) were increased in colon tissue. Moreover, the levels of critical pathway proteins involved in the inflammatory process (p-STAT3 and p-JNK) and cell cycle regulation molecules (ß-catenin, c-Myc and CylinD1) exhibited lower expression levels. Besides, 16S rRNA sequence analysis indicated that pre-administration of BBR increased the ratio of Firmicutes/Bacteroidetes (F:M) and the relative abundance of potentially beneficial bacteria, while the abundance of cancer-related bacteria was decreased. Gavage with Lactobacillus rhamnosus can improve the anti-tumor effect of BBR. Overall, pre-administration of BBR exerts preventive effects in colon carcinogenesis, and the mechanisms underlying these effects are correlated with the inhibition of inflammation and tumor proliferation and the maintenance of intestinal homeostasis.