Promotes Cancer Metastasis Research Articles

Extruded small extracellular vesicles: splinters of circulating tumour cells may promote cancer metastasis?

We speculate ruptured circulating tumour cells (CTC) in capillaries could release a large number of small extracellular vesicle-like vesicles, namely mechanically extruded sEV (sEVme), which can encapsulate chromosomal DNA fragments. These sEVme have similar physicochemical properties compared to small extracellular vesicles spontaneously secreted by living cells (sEVss), and thus sEVme and sEVss cannot be effectively distinguished based on their size or membrane protein markers. Meanwhile, these sEVme derived from CTC inherit oncogenic payloads, deliver cargo through the bloodstream to recipient cells, and thus may promote cancer metastasis. The validation of this speculation could facilitate our understanding of EV biogenesis and cancer pathology. The potential finding will also provide a theoretical foundation for burgeoning liquid biopsy using DNA fragments derived from harvested sEV.

Environment-Sensitive Ectodomain Shedding of Epithin/PRSS14 Increases Metastatic Potential of Breast Cancer Cells by Producing CCL2.

Epithin/PRSS14 is a membrane serine protease that plays a key role in tumor progression. The protease exists on the cell surface until its ectodomain shedding, which releases most of the extracellular domain. Previously, we showed that the remaining portion on the membrane undergoes intramembrane proteolysis, which results in the liberation of the intracellular domain and the intracellular domain-mediated gene expression. In this study, we investigated how the intramembrane proteolysis for the nuclear function is initiated. We observed that ectodomain shedding of epithin/PRSS14 in mouse breast cancer 4T1 cells increased depending on environmental conditions and was positively correlated with invasiveness of the cells and their pro-invasive cytokine production. We identified selenite as an environmental factor that can induce ectodomain shedding of the protease and increase C-C motif chemokine ligand 2 (CCL2) secretion in an epithin/PRSS14-dependent manner. Additionally, by demonstrating that the expression of the intracellular domain of epithin/PRSS14 is sufficient to induce CCL2 secretion, we established that epithin/PRSS14-dependent shedding and its subsequent intramembrane proteolysis are responsible for the metastatic conversion of 4T1 cells under these conditions. Consequently, we propose that epithin/PRSS14 can act as an environment-sensing receptor that promotes cancer metastasis by liberating the intracellular domain bearing transcriptional activity under conditions promoting ectodomain shedding.

Multifaceted role of RNA editing in promoting loss-of-function of PODXL in cancer

SummaryPODXL, a protein that is dysregulated in multiple cancers, plays an important role in promoting cancer metastasis. In this study, we report that RNA editing promotes the inclusion of a PODXL alternative exon. The resulting edited PODXL long isoform is more prone to protease digestion and has the strongest effects on reducing cell migration and cisplatin chemoresistance among the three PODXL isoforms (short, unedited long, and edited long isoforms). Importantly, the editing level of the PODXL recoding site and the inclusion level of the PODXL alternative exon are strongly associated with overall patient survival in Kidney Renal Clear Cell Carcinoma (KIRC). Supported by significant enrichment of exonic RNA editing sites in alternatively spliced exons, we hypothesize that exonic RNA editing sites may enhance proteomic diversity through alternative splicing, in addition to amino acid changes, a previously under-appreciated aspect of RNA editing function.

Gastric cancer cell-derived extracellular vesicles disrupt endothelial integrity and promote metastasis

The endothelium is the critical barrier that controls transendothelial communications. Blood vessels in cancer tissue are poorly developed and highly permeable. However, it is poorly understood how circulating cancer cells released through these “leaky” vessels break the intact vasculature of remote organs to metastasize. We investigated the roles of cancer cell-derived extracellular vesicles (CEVs) in regulating cancer metastasis by analyzing samples from gastric cancer patients, performing in vitro experiments, and studying mouse models. We made several novel observations. First, the rate of metastasis was closely associated with plasma levels of CEVs in patients with gastric cancer. Second, cultured endothelial cells endocytosed CEVs, resulting in cytoskeletal rearrangement, low expression of the junction proteins cadherin and CD31, and forming large intercellular gaps to allow the transendothelial migration of cancer cells. The dynamin inhibitor Dynasore prevented these CEV-induced changes of endothelial cells by blocking CEVs endocytosis. Third, CEVs disrupted the endothelial barrier of cancer-bearing mice to promote cancer metastasis. Finally, lactadherin promoted the clearance of circulating CEVs to reduce metastasis. These results demonstrate the essential role of CEVs in promoting the metastasis of gastric cancer.

Exosome-mediated transduction of mechanical force regulates prostate cancer migration via microRNA

Physical cues in the extracellular microenvironment regulate cancer cell metastasis. Functional microRNA (miRNA) carried by cancer derived exosomes play a critical role in extracellular communication between cells and the extracellular microenvironment. However, little is known about the role of exosomes loaded miRNAs in the mechanical force transmission between cancer cells and extracellular microenvironment. Herein, our results suggest that stiff extracellular matrix (ECM) induced exosomes promote cancer cell migration. The ECM mechanical force regulated the exosome miRNA cargo of prostate cancer cells. Exosome miRNAs regulated by the ECM mechanical force modulated cancer cell metastasis by regulating cell motility, ECM remodeling and the interaction between cancer cells and nerves. Focal adhesion kinase mediated-ECM mechanical force regulated the intracellular miRNA expression, and F-actin mediate-ECM mechanical force regulated miRNA packaging into exosomes. The above results demonstrated that the exosome miRNA cargo promoted cancer metastasis by transmitting the ECM mechanical force. The ECM mechanical force may play multiple roles in maintaining the microenvironment of cancer metastasis through the exosome miRNA cargo.

HBx Mediated Increase of DDX17 Contributes to HBV-Related Hepatocellular Carcinoma Tumorigenesis.

HBV is strongly associated with HCC development and DEAD-box RNA helicase 17 (DDX17) is a very important member of the DEAD box family that plays key roles in HCC development by promoting cancer metastasis. However, the important role of DDX17 in the pathogenesis of HBV-related HCC remains unclear. In this study, we investigated the role of DDX17 in the replication of HBV and the development of HBV-associated HCC. Based on data from the GEO database and HBV-infected cells, we found that DDX17 was upregulated by the HBV viral protein X (HBx). Mechanistically, increased DDX17 expression promoted HBV replication and transcription by upregulating ZWINT. Further study showed that DDX17 could promote HBx-mediated HCC metastasis. Finally, the promotive effect of DDX17 on HBV and HBV-related HCC was confirmed in vivo. In summary, the results revealed the novel role of DDX17 in the replication of HBV and the metastasis of HBV-associated HCC.

Abstract 3353: Discovery and validation of orphan noncoding RNA profiles across multiple cancers in TCGA and two independent cohorts

Abstract Small non-coding RNAs (sncRNAs) have established roles as post-transcriptional regulators of cancer pathogenesis. We recently reported a novel and previously unannotated class of cancer-specific sncRNAs in breast cancer and demonstrated that breast cancer cells exploit a specific sncRNA to promote cancer metastasis. However, the extent to which these sncRNAs, which we have collectively termed orphan non-coding RNAs (oncRNAs), are present in other cancer types is unknown. To address this question and define a high-confidence set of oncRNAs, we used smRNA-seq data from 6 cancer sites (breast, colorectal, kidney, liver, lung, and stomach) and their corresponding normal tissues from The Cancer Genome Atlas (TCGA; 4,445 cancer, 431 normal) and identified a total of 144,695 oncRNAs that are significantly present in cancer and largely absent in normal tissue (Fisher’s Exact Test and Benjamini-Hochberg correction, FDR < 0.1). To evaluate if this set of TCGA-derived oncRNAs could be validated in independent datasets, we examined smRNA-seq data from two large independent cohorts comprising these same cancer and normal tissue types (Indivumed, Hamburg, Germany). Cohort A consists of 4,024 samples (2,245 cancer, 1,779 normal) and cohort B consists of 2,874 samples (2,063 cancer; 811 normal). oncRNAs in these cohorts were annotated following the same procedure used for TCGA data. TCGA-derived oncRNAs were considered validated in the independent cohorts if they were present in a significantly higher number of cancer samples compared to adjacent normal tissue samples. In cohort A, 140,191 (96.9%) of TCGA-derived oncRNAs were detected in at least one sample, of which 74,634 (51.6%) were validated as oncRNAs. In cohort B, 140,147 (96.9%) oncRNAs were observed and 68,366 (47.2%) were validated. The degree of overlap between the validated oncRNAs in each cohort was significant, with 54,294 (37.5%) overlapping oncRNAs (hypergeometric test, P=0). We also found that oncRNAs are informative of cancer tissue of origin, demonstrating the existence of consistent cancer-specific oncRNA expression profiles in independent studies. Using the TCGA-derived oncRNAs as features, we trained an eXtreme Gradient Boosting (XGB) model on TCGA data to classify cancer samples by the 6 tissues of origin. The TCGA-trained model showed high performance when evaluated on both cohorts A and B, achieving accuracies of 91.5% (95% CI: 90.3%-92.7%) and 96% (94.7%-97%), respectively. For comparison, this model achieved an accuracy of 96% (94.5%-97.2%) on held-out TCGA data (80/20 train/test split). Our results show a robust validation of TCGA-derived oncRNAs in external, independently sourced and processed cancer tissue cohorts across a heterogeneous set of cancer sites. Our machine learning model also demonstrates that oncRNA profiles can be used to predict cancer tissue of origin with high generalizability and accuracy. Citation Format: Jeffrey Wang, Helen Li, Lisa Fish, Kimberly H. Chau, Patrick Arensdorf, Hani Goodarzi, Babak Alipanahi. Discovery and validation of orphan noncoding RNA profiles across multiple cancers in TCGA and two independent cohorts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3353.

Abstract 2462: Rac and p-PAK expression among Puerto Rican breast cancer patients

Abstract Breast cancer is the most common cancer among US women and is the second leading cause of death from cancer. Since metastasis is a major cause of death from breast cancer, we focused on Rac, a key metastasis driver regulating cancer cell migration and invasion. The direct downstream effector of Rac, p21-activated kinase (PAK), is auto-phosphorylated (in Thr 423) when activated by Rac to promote cancer metastasis. Accordingly, Rac and PAK expression is associated with higher stages and grades of multiple cancers and is also increased in breast ductal carcinoma and lymph node metastases. The breast cancer incidence in Puerto Rico (PR) is lower than that of the mainland US; however, mortality rates are higher due to increased invasion and metastasis. Therefore, the objective in this study was to determine Rac and phospho (p)-PAK expression in breast cancer tissues from Puerto Rican patients. Consecutive cases of formalin-fixed paraffin embedded infiltrating mammary carcinomas from core needle biopsy samples were obtained from the Auxilio Mutuo Hospital, San Juan, PR. Our initial study was limited to estrogen receptor (ER)/progesterone receptor (PR) positive (+) patients with variable human epidermal growth factor receptor (HER2) status. Of the 16 patients studied, 10 were HER2 negative and 6 were HER2 positive. Histologic tumor grade via Nottingham criteria was determined and immunohistochemical stains for ER, PR, HER2 protein and Ki-67 were performed, as well as HER2 in situ hybridization for final determination of HER2 status. To evaluate the expression of Rac1, we used immunofluorescence (IMFL) with specific antibodies. p-PAK status was evaluated via immunohistochemistry (IHC) with specific antibodies to p-Thr423-PAK. The IMFL and IHC scores were determined by analyzing the staining intensity graded as follows: 0, no staining; 1, weak staining; 2, moderate staining; 3, strong staining. There were no significant differences in Rac1 expression based on HER2, ER, or PR status or Tumor Grade. Since Rac1 is activated via upstream receptor signaling such as HER2, we determined p-PAK staining as a measure of Rac activity. p-PAK staining was detected in ductal carcinoma (DC) in situ and invasive DC, with stronger staining in cancer cells infiltrating the surrounding tissue. p-PAK levels were elevated in HER2 positive compared to HER2 negative breast tumor tissue, independent of ER or PR status. Based on this data, we posit that selective Rac activation in HER2 positive breast cancers contribute to enhanced cancer malignancy in Puerto Rican patients. This will be validated by a larger sample size of breast cancer tissue comparing HER2/ER/PR status and cancer grade from Puerto Rican (Hispanic) and Caucasian patients. Citation Format: Mariangeline I. Gonzalez Ortiz, Magaly Martinez-Ferrer, Victor P. Carlo, Suranganie Dharmawardhane. Rac and p-PAK expression among Puerto Rican breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2462.

Monocyte-Macrophage Lineage Cell Fusion.

Cell fusion (fusogenesis) occurs in natural and pathological conditions in prokaryotes and eukaryotes. Cells of monocyte–macrophage lineage are highly fusogenic. They create syncytial multinucleated giant cells (MGCs) such as osteoclasts (OCs), MGCs associated with the areas of infection/inflammation, and foreign body-induced giant cells (FBGCs). The fusion of monocytes/macrophages with tumor cells may promote cancer metastasis. We describe types and examples of monocyte–macrophage lineage cell fusion and the role of actin-based structures in cell fusion.

Mitochondrial Dysfunction and the Glycolytic Switch Induced by Caveolin-1 Phosphorylation Promote Cancer Cell Migration, Invasion, and Metastasis.

Simple SummaryCaveolin-1 (CAV1) is a membrane protein that has been attributed a dual role in cancer, acting at early stages as a tumor suppressor and in later stages of the disease as a promoter of metastasis. In the latter case, enhanced expression of CAV1 favors the malignant phenotype and correlates with a poorer prognosis of the patients. Bearing in mind that the reprogramming of energy metabolism is required in cancer cells to meet both the bioenergetic and biosynthetic needs to sustain increased proliferation, migration, and invasion, we evaluated the metabolism of metastatic cells expressing or not CAV1. In this study, we show that the expression of CAV1 promotes in cancer cells a metabolic switch to an aerobic, glycolytic phenotype by blocking mitochondrial respiration. Cancer cells often display impaired mitochondrial function, reduced oxidative phosphorylation, and augmented aerobic glycolysis (Warburg effect) to fulfill their bioenergetic and biosynthetic needs. Caveolin-1 (CAV1) is a scaffolding protein that promotes cancer cell migration, invasion, and metastasis in a manner dependent on CAV1 phosphorylation on tyrosine-14 (pY14). Here, we show that CAV1 expression increased glycolysis rates, while mitochondrial respiration was reduced by inhibition of the mitochondrial complex IV. These effects correlated with increased reactive oxygen species (ROS) levels that favored CAV1-induced migration and invasion. Interestingly, pY14-CAV1 promoted the metabolic switch associated with increased migration/invasion and augmented ROS-inhibited PTP1B, a phosphatase that controls pY14 levels. Finally, the glycolysis inhibitor 2-deoxy-D-glucose reduced CAV1-enhanced migration in vitro and metastasis in vivo of murine melanoma cells. In conclusion, CAV1 promotes the Warburg effect and ROS production, which inhibits PTP1B to augment CAV1 phosphorylation on tyrosine-14, thereby increasing the metastatic potential of cancer cells.

The binding between NPM and H2B proteins signals for the diabetes-associated centrosome amplification.

Diabetes not only increases the risk for cancer but also promotes cancer metastasis. Centrosome amplification (CA) is sufficient to initiate tumorigenesis and can enhance the invasion potential of cancer cells. We have reported that diabetes can induce CA, with diabetic pathophysiological factors as the triggers, which involves the signaling of nucleophosmin(NPM). Thus, CA can serve as a candidate biological link between diabetes and cancer. In the present study, we attempted to identify the NPMbinding partners and investigated whether the binding between NPMand its partner mediated the CA. We confirmed that high glucose, insulin, and palmitic acid cancer could elicit CA in the HCT16 colon cancer cells and found that the experimental treatment increased the binding between NPMand H2B, but not between p-NPMand H2B. The molecular docking analysis supported the fact that NPMand H2B could bind to each other through various amino acid residues. The treatment also increased the colocalization of NPMand H2B in the cytosol. Importantly, disruption of the NPM1-H2B complex by individualknockdown of the protein level of NPMor H2B led to the inhibition of the treatment-evoked CA. In conclusion, our results suggest that the binding between NPMand H2B proteins signals for the CA by high glucose, insulin, and palmitic acid.

Targeting MDK Abrogates IFN-γ-Elicited Metastasis inCancers of Various Origins.

IFN-γ is a pleiotropic cytokine with immunomodulatory and tumoricidal functions. It has been used as an anti-tumor agent in adjuvant therapies for various cancers. Paradoxically, recent advances have also demonstrated pro-tumorigenic effects of IFN-γ, especially in promoting cancer metastasis, with the mechanism remains unclear. This will undoubtedly hinder the application of IFN-γ in cancer treatment. Here, we verified that IFN-γ treatment led to activation of the epithelial-to-mesenchymal transition (EMT) programme and metastasis in cell lines of various cancers, including the kidney cancer cell line Caki-1, the lung cancer cell line A549, the cervical carcinoma cell line CaSki, the breast cancer cell line BT549 and the colon cancer cell line HCT116. We further disclosed that midkine (MDK), an emerging oncoprotein and EMT inducer, is a common responsive target of IFN-γ in these cell lines. Mechanistically, IFN-γ upregulated MDK via STAT1, a principle downstream effector in the IFN-γ signalling. MDK is elevated in the majority of cancer types in the TCGA database, and its overexpression drove EMT activation and cancer metastasis in all examined cell lines. Targeting MDK using a specific MDK inhibitor (iMDK) broadly reversed IFN-γ-activated EMT, and subsequently abrogated IFN-γ-triggered metastasis. Collectively, our data uncover a MDK-dependent EMT inducing mechanism underlying IFN-γ-driven metastasis across cancers which could be attenuated by pharmacological inhibition of MDK. Based on these findings, we propose that MDK may be used as a potential therapeutic target to eliminate IFN-γ-elicited pro-metastatic adverse effect, and that combined MDK utilization may expand the application of IFN-γ in cancer and improve the clinical benefits from IFN-γ-based therapies.

Receptor Activity Modifying Protein RAMP Sub-Isoforms and Their Functional Differentiation, Which Regulates Functional Diversity of Adrenomedullin.

Simple SummaryThe body contains a variety of humoral bioactive factors and information regulation systems that maintain homeostasis. Although adrenomedullin (AM) was first identified as a vasodilator peptide, subsequent studies have revealed that it plays an essential role in homeostasis in vivo and possesses a variety of bioactivities other than vasodilation. Based on its structural homology, AM is classified as a member of the calcitonin superfamily, which includes calcitonin, calcitonin gene-related peptide (CGRP), amylin, and intermedin. Peptides belonging to the calcitonin superfamily are characterized by a partial sharing of their receptor system. One of the sub-isoforms of receptor activity-modifying protein (RAMP) binds to calcitonin receptor-like receptor (CLR), a 7-transmembrane G protein, in a one-to-one manner, and then functions as a receptor for these peptides. Among RAMP isoforms, we focused on RAMP2 and RAMP3. Each RAMP isoform is expected to be a potential therapeutic target for various diseases, including cardiovascular diseases and cancer metastasis. In this review, we outline the pathophysiological significance and functional differentiation of RAMP2 and RAMP3, as mainly revealed by the analysis of genetically engineered mice.AM knockout (AM-/-) and RAMP2 knockout (RAMP2-/-) proved lethal for mice due to impaired embryonic vascular development. Although most vascular endothelial cell-specific RAMP2 knockout (E-RAMP2-/-) mice also died during the perinatal period, a few E-RAMP2-/- mice reached adulthood. Adult E-RAMP2-/- mice developed spontaneous organ damage associated with vascular injury. In contrast, adult RAMP3 knockout (RAMP3-/-) mice showed exacerbated postoperative lymphedema with abnormal lymphatic drainage. Thus, RAMP2 is essential for vascular development and homeostasis and RAMP3 is essential for lymphatic vessel function. Cardiac myocyte-specific RAMP2 knockout mice showed early onset of heart failure as well as abnormal mitochondrial morphology and function, whereas RAMP3-/- mice exhibited abnormal cardiac lymphatics and a delayed onset of heart failure. Thus, RAMP2 is essential for maintaining cardiac mitochondrial function, while RAMP3 is essential for cardiac lymphangiogenesis. Transplantation of cancer cells into drug-inducible vascular endothelial cell-specific RAMP2 knockout mice resulted in enhanced metastasis to distant organs, whereas metastasis was suppressed in RAMP3-/- mice. RAMP2 suppresses cancer metastasis by maintaining vascular homeostasis and inhibiting vascular inflammation and pre-metastatic niche formation, while RAMP3 promotes cancer metastasis via malignant transformation of cancer-associated fibroblasts. Focusing on the diverse physiological functions of AM and the functional differentiation of RAMP2 and RAMP3 may lead to the development of novel therapeutic strategies.

Cancer-Secreted Exosomal MiR-620 Inhibits ESCC Aerobic Glycolysis via FOXM1/HER2 Pathway and Promotes Metastasis.

BackgroundEsophageal squamous cell carcinoma (ESCC) is a leading cause of cancer death worldwide. MicroRNAs (MiRNAs) have been reported to regulate cell functions through exosomes. Through the Gene Expression Omnibus (GEO) database, miR-620 was selected as a serum miRNA highly expressed in ESCC, but its detailed role in ESCC has not been explored. Tumor-secreted miRNAs have been reported to promote cancer metastasis through reprogramming the aerobic glycolysis of lung fibroblasts. Therefore, we intended to verify whether exosomal miR-620 secreted in ESCC cells may regulate the aerobic glycolysis of lung fibroblasts.MethodsThe effect of miR-620 on the aerobic glycolysis of ESCC cells was firstly verified through bioinformatics prediction and mechanism assays. Exosomes secreted from ESCC cells was detected, and the influence of exosomal miR-620 in regulating the aerobic glycolysis of lung fibroblasts was then verified both in vitro and in vivo.ResultsMiR-620 inhibited ESCC malignancy and suppressed the aerobic glycolysis of ESCC cells via targeting Forkhead box M1 (FOXM1) and human epidermal growth factor receptor 2 (HER2). Moreover, exosomal miR-620 was highly secreted in ESCC and could regulate HFL1 aerobic glycolysis via FOXM1/HER2 signaling. Furthermore, exosomal miR-620 could promote ESCC metastasis by reprogramming the aerobic glycolysis of lung fibroblasts (HFL1).ConclusionExosomal miR-620 secreted by ESCC cells inhibited the aerobic glycolysis via FOXM1/HER2 axis and promoted cancer metastasis.

Anti-HIV Drug Elvitegravir Suppresses Cancer Metastasis via Increased Proteasomal Degradation of m6A Methyltransferase METTL3.

This study finds that METTL3 promotes cancer metastasis by activating EGR1/Snail signaling in an m6A-dependent manner, revealing vulnerability to METTL3 blockade in esophageal squamous cell carcinoma.

The Identification of NIFK’s RNA Binding Targets and Its Prognostic Values in Lung Cancer

BackgroundWe previously identified nucleolar protein interacting with the FHA domain of pKi‐67 (NIFK) as a poor prognostic marker in lung cancer. Furthermore, NIFK overexpression promotes cancer metastasis via decreasing casein kinase 1α (CK1α) expression, a suppressor of pro‐metastatic TCF4/β‐catenin signaling. We further observe the axis is induced by the downregulation of a novel transcription factor RUNX1. It is also known for NIFK’s biological function in regulating RNA metabolism via RNA recognition motif (RRM). However, a comprehensive analysis for identifying the RNA binding targets has not yet been reported. In this study, we aim to unravel the interactive mechanism and to characterize its potential clinical value in cancer patient cohort.MethodNIFK is pointed out to possess RNA binding function via RRM. RNA immunoprecipitation assay was performed using specific NIFK antibody in lung cancer PC13 and A549 cells after NIFK overexpression. RNA targets were analyzed by RT‐PCR and Next Generation Sequencing (NGS). In addition, expression levels were investigated by IHC staining and omics data mining. The association of the respective expression with patient survival outcome were explored in lung cancer cohorts.ResultsWe observe the increase in amount of RNA binding targets after NIFK overexpression respectively in PC13 and A549 cells as comparing with the control. Moreover, NIFK appears to bind with RUNX1 RNA but not CK1α suggesting it is the initial step of NIFK‐mediated TCF4/β‐catenin signaling regulation. NIFK also leads to RUNX1 RNA instability of which mechanism remains to be explored. RUNX1 level is observed to associate with good prognosis in lung cancer datasets (jacob‐00182‐CANDF and GSE13213). Furthermore, direct interactive RNA targets of NIFK are identified by RNA immunoprecipitation and RNA‐Seq, which indicate SYNE2 as one of targets with prognostic significance in lung cancer. Increased SYNE2 is detected upon NIFK overexpression, and the lung cancer patients stratified in high SYNE2 group appear to associate with inferior clinical outcomes.ConclusionWe first show the interactive mechanism of pro‐metastatic molecule NIFK in regulating TCF4/β‐catenin signaling and SYNE2, which might provide insights into therapeutic development for lung cancer patients.

Elucidation of CKAP4-remodeled cell mechanics in driving metastasis of bladder cancer through aptamer-based target discovery

Metastasis contributes to the dismal prognosis of bladder cancer (BLCA). The mechanical status of the cell membrane is expected to mirror the ability of cell migration to promote cancer metastasis. However, the mechanical characteristics and underlying molecular profile associated with BLCA metastasis remain obscure. To study the unique cellular architecture and traits associated with cell migration, using a process called cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX) we generated an aptamer-based molecular probe, termed spl3c, which identified cytoskeleton-associated protein 4 (CKAP4). CKAP4 was associated with tumor metastasis in BLCA, but we also found it to be a mechanical regulator of BLCA cells through the maintenance of a central-to-peripheral gradient of stiffness on the cell membrane. Notably, such mechanical traits were transportable through exosome-mediated intercellular CKAP4 trafficking, leading to significant enhancement of migration in recipient cells and, consequently, aggravating metastatic potential in vivo. Taken together, our study shows the robustness of this aptamer-based molecular tool for biomarker discovery, revealing the dominance of a CKAP4-induced central-to-peripheral gradient of membrane stiffness that benefits cell migration and delineating the role of exosomes in mediating mechanical signaling in BLCA metastasis.

Tumor-resident intracellular microbiota promotes metastatic colonization in breast cancer

Tumor-resident intracellular microbiota is an emerging tumor component that has been documented for a variety of cancer types with unclear biological functions. Here, we explored the functional significance of these intratumor bacteria, primarily using a murine spontaneous breast-tumor model MMTV-PyMT. We found that depletion of intratumor bacteria significantly reduced lung metastasis without affecting primary tumor growth. During metastatic colonization, intratumor bacteria carried by circulating tumor cells promoted host-cell survival by enhancing resistance to fluid shear stress by reorganizing actin cytoskeleton. We further showed that intratumor administration of selected bacteria strains isolated from tumor-resident microbiota promoted metastasis in two murine tumor models with significantly different levels of metastasis potential. Our findings suggest that tumor-resident microbiota, albeit at low biomass, play an important role in promoting cancer metastasis, intervention of which might therefore be worth exploring for advancing oncology care.

Hexavalent chromium induces centrosome amplification through ROS-ATF6-PLK4 pathway in colon cancer cells.

Centrosome amplification (CA) refers to a numerical increase in centrosomes resulting in cells with more than two centrosomes. CA has been shown to initiate tumorigenesis and increase the invasive potential of cancer cells in genetically modified experimental models. Hexavalent chromium is a recognized carcinogen that causes CA and tumorigenesis as well as promotes cancer metastasis. Thus, CA appears to be a biological link between chromium and cancer. In the present study, we investigated how chromium triggers CA. Our results showed that a subtoxic concentration of chromium-induced CA in HCT116 colon cancer cells, resulted in the production of reactive oxygen species (ROS), activated ATF6 without causing endoplasmic reticulum stress, and upregulated the protein level of PLK4. Inhibition of ROS production, ATF6 activation, or PLK4 upregulation attenuated CA. Inhibition of ROS using N-acetyl-l-cysteine (NAC) inhibited chromium-induced activation of ATF6 and upregulation of PLK4. ATF6-specific siRNA knocked down the protein level and activation of ATF6, and upregulated PLK4, with no effect on ROS production. Knockdown of PLK4 protein had no effect on chromium-induced ROS production or activation of ATF6. In conclusion, our results suggest that hexavalent chromium induces CA via the ROS-ATF6-PLK4 pathway and provides molecular targets for inhibiting chromium-mediated CA, which may be useful for the assessment of CA in chromium-promoted tumorigenesis and cancer cell metastasis.

HSP40 Family Member DNAJA1 Promotes Cancer Metastasis through Interaction with Mutant p53

HSP40 Family Member DNAJA1 Promotes Cancer Metastasis through Interaction with Mutant p53