Specific Myosins Control Actin Organization, Cell Morphology, and Migration in Prostate Cancer Cells

Myosin 1b Inhibits the Phenotype of HemECs to Affect the Progression of Infantile Hemangiomas

Purpose

To investigate the role of myosin 1b (Myo1b) in infantile hemangiomas (IHs).

Patients and Methods

The expression of Myo1b in IHs and normal skin tissues was evaluated using immunohistochemical techniques. Expression of Myo1b in hemangioma endothelial cells (HemECs) was detected using quantitative real-time polymerase chain reaction and Western blotting techniques. The effects of Myo1b on cell proliferation, invasion, tube formation and other biological characteristics were analyzed. A mouse model was established to observe the inhibitory effects of Myo1b in vivo. Protein expression of peroxisome proliferator-activated receptor-gamma (PPARγ) and glucose transporter 1 protein (Glut-1) in a Myo1b knockdown HemECs was detected using Western blot.

Results

Myo1b was highly expressed in the proliferative stage of IHs, and promoted proliferation, invasion, and angiogenesis in vitro. Mouse models further demonstrated that Myo1b inhibited proliferation and angiogenesis of IHs. Knockdown of Myo1b inhibited Glut-1 activity, promoted expression of PPARγ transcription factor.

Conclusion

Myo1b has a pro-tumor effect on IHs, knockdown of Myo1b facilitated progression of the proliferating to involution phase of IHs. Therefore, Myo1b is expected to serve as a new target for the treatment of IHs.

Transcriptomic analysis of human castration-resistant prostate cancer: Insights into novel therapeutic strategies

Prostate cancer is a major cause of cancer-related deaths in men worldwide. Androgen deprivation therapy (ADT) is the standard treatment for advanced prostate cancer; however, disease progression to castration-resistant prostate cancer (CRPC) presents a significant therapeutic challenge. In this study, we employed transcriptomic analysis to investigate key genetic drivers of CRPC and identify novel therapeutic targets. Using RNA-seq data and bioinformatics tools, we identified differentially expressed genes (DEGs) associated with tumor progression, cytoskeletal dynamics, and immune modulation, including COL3A1, MYH4, FN1, ACTN1, and CALR. Functional enrichment analysis revealed significant involvement of actin-myosin filament sliding, calcium signaling, androgen receptor signaling, immune evasion, and metabolic pathways, underscoring their roles in CRPC progression and treatment resistance. Additionally, molecular docking studies demonstrated strong binding interactions between key CRPC-related genes (ABCC4 and FOLH1) and potential therapeutic ligands, including flutamide and N-acetyl glucosamine (NAG), highlighting their therapeutic potential in overcoming drug resistance. These findings provide novel insights into the molecular landscape of CRPC and support the development of precision-targeted therapies to improve patient outcomes.

Souza KB, Forti FL, de Alencar BC. Myosin IXB protects immune cells from virus infection

Actin-associated proteins have been implicated in several stages of virus infection. However, the role of myosins, which are actin-dependent molecular motors, during virus infection and pathogenesis is poorly understood. Myosin IXB (Myo9b) is a member of the myosin family abundantly expressed in immune cells. Myo9b displays a RhoGTPase-activating protein domain capable of modulating actin dynamics by inhibiting RhoGTPase activity. To enquire upon Myo9b participation in virus infections, we have silenced Myo9b in U937 and Jurkat cells and infected them with vesicular stomatitis virus glycoprotein (VSV-G)-pseudotyped HIV-1. Myo9b-silenced U937 showed a remarkable increase of above ten times more HIV-VSV-G infection than control cells. We observed a similar pattern in Jurkat cell infection with both WT Env and VSV-G-pseudotyped HIV, albeit to a lesser extent. Myo9b-silenced U937 cells presented elevated levels of phosphorylated cofilin, but lower levels of polymerized actin. The use of a RhoA, B and C inhibitor, as well as a Rac1 inhibitor, reduced virus infection. Finally, we have also observed an increment in virus internalization and fusion in cells knockdown for Myo9b, which may explain the increase in virus infection. Taken together, our data suggests that Myo9b might hinder viral entry and infection by controlling the activity of RhoGTPases in immune cells.

Exploring the impact of cuproptosis on prostate cancer prognosis via RNA methylation regulation based on single cell and bulk RNA sequencing data

Background

Cuproptosis, along with RNA methylation regulators, has recently come to the fore as innovative mechanisms governing cell death, exerting profound impact on the onset and progression of multiple cancers. Nonetheless, the prognostic implications and underlying regulatory mechanisms of them associated with prostate cancer (PCa) remain to be thoroughly investigated.

Methods

Genomic and clinical data for PCa from The Cancer Genome Atlas datasets were analyzed to identify a prognostic model through univariate and Least Absolute Shrinkage and Selection Operator Cox regression analyses that were validated utilizing external datasets. We used receiver operating characteristic curves and C-index to evaluate the accuracy of our prognostic model. In conjunction with this, we conducted single-cell RNA sequencing (scRNA-seq) analyses to investigate underlying mechanisms and evaluate the degree of immune infiltration, as well as to assess patients' responses to diverse chemotherapy agents. Especially, qPCR assay was utilized to unveil the expression of signature genes in PCa.

Results

We meticulously selected six Cuproptosis-Associated RNA Methylation Regulators (CARMRs) to establish a risk prognosis model, which was further verified to obtain enhanced predictive capacity in external validation cohorts. Insights from immune infiltration and scRNA-seq analyses have elucidated the immune characteristics of PCa, and highlighted the immunosuppressive role of regulatory T cells on immune response. Additionally, drug susceptibility analysis demonstrated that patients with PCa in the low-risk category derived better benefit from bicalutamide treatment, whereas those in the high-risk group exhibited a favor response to adriamycin and docetaxel treatments. The qPCR and immunohistochemistry (IHC) staining assays also reveal the a dramatically altered expression pattern of TRDMT1 and ALYREF in PCa tissues.

Conclusion

In general, we established a model involving CARMRs that can better predict the risk of recurrence of PCa and have identified the possible mechanisms affecting PCa progression, thereby promoting further research in this field.

Unveiling ac4C modification pattern: a prospective target for improving the response to immunotherapeutic strategies in melanoma

Emerging evidence has confirmed the inextricable connection between N4-acetylcytidine (ac4C) mRNA modification and the clinical characteristics of malignancies. Nonetheless, it is uncertain whether and how ac4C mRNA modification patterns affect clinical outcomes in melanoma patients. This research integrated single-cell sequencing data and transcriptomics to pinpoint ac4C-related genes (acRG) linked to melanoma progression and evaluate their clinical implications. Cells with elevated acRG score were predominantly located within the melanocytes cluster. Intercellular communications between melanocytes and other cell subtypes were markedly strengthened in the acRG-high group. We developed and confirmed an excellent acRG-related signature (acRGS) utilizing a comprehensive set of 101 algorithm combinations derived from 10 machine learning algorithms. Hereby, the acRGS, including MYO10, ZNF667, MRAS, SCO2, MAPK10, PNMA6A, KPNA2, NT5DC2, BAIAP2L2 and NDST3, delineated ac4C-associated mRNA modification patterns in melanoma. The acRGS possesses distinctly superior performance to 120 previously reported signatures in melanoma and could predict the overall survival of melanoma patients across four external datasets. The substantial associations among immune checkpoint genes, immune cell infiltration, and tumor mutation burden with acRGS indicate that acRGS is helpful in identifying melanoma patients who are sensitive to immunotherapy. Besides, we confirmed that MYO10 was mainly overexpressed in melanoma tissues, and elevated MYO10 was positively correlated with malignant phenotypes and unfavorable prognosis in melanoma patients. Silencing MYO10 expression inhibited melanoma cell proliferation, migration and invasion in vitro as well as tumor growth in vivo. Taken together, the acRGS could function as a reliable and prospective tool to improve the clinical prognosis for melanoma individuals.

MIRO2 promotes cancer invasion and metastasis via MYO9B suppression of RhoA activity

Metastasis to vital organs remains the leading cause of cancer-related deaths, emphasizing an urgent need for actionable targets in advanced-stage cancer. The role of mitochondrial Rho GTPase 2 (MIRO2) in prostate cancer growth was recently reported; however, whether MIRO2 is important for additional steps in the metastatic cascade is unknown. Here, we show that knockdown of MIRO2 ubiquitously reduces tumor cell invasion in vitro and suppresses metastatic burden in prostate and breast cancer mouse models. Mechanistically, depletion of MIRO2's binding partner-unconventional myosin 9B (MYO9B)-reduces tumor cell invasion and phenocopies MIRO2 depletion, which in turn results in increased active RhoA. Furthermore, dual ablation of MIRO2 and RhoA fully rescues tumor cell invasion, and MIRO2 is required for MYO9B-driven invasion. Taken together, we show that MIRO2 supports invasion and metastasis through cooperation with MYO9B, underscoring a potential targetable pathway for patients with advanced disease.

Myosin 1e deficiency affects migration of 4T1 breast cancer cells

Metastasis of breast cancer cells to distant tissue sites is responsible for the majority of deaths associated with breast cancer. Previously we have examined the role of class I myosin motor protein, myosin 1e (myo1e), in cancer metastasis using the Mouse Mammary Tumor Virus-Polyoma Middle T Antigen (MMTV-PyMT) mouse model. Mice deficient in myo1e formed tumors with a more differentiated phenotype relative to the wild-type mice and formed no detectable lung metastases. In the current study, we investigated how the absence of myo1e affects cell migration and invasion in vitro, using the highly invasive and migratory breast cancer cell line, 4T1. 4T1 cells deficient in myo1e exhibited an altered morphology and slower rates of migration in the wound-healing and transwell migration assays compared to the WT 4T1 cells. While integrin trafficking and Golgi reorientation did not appear to be altered upon myo1e loss, we observed lower rates of focal adhesion disassembly in myo1e-deficient cells, which could help explain the cell migration defect.

An allosteric inhibitor of RhoGAP class-IX myosins suppresses the metastatic features of cancer cells

Aberrant Ras homologous (Rho) GTPase signalling is a major driver of cancer metastasis, and GTPase-activating proteins (GAPs), the negative regulators of RhoGTPases, are considered promising targets for suppressing metastasis, yet drug discovery efforts have remained elusive. Here, we report the identification and characterization of adhibin, a synthetic allosteric inhibitor of RhoGAP class-IX myosins that abrogates ATPase and motor function, suppressing RhoGTPase-mediated modes of cancer cell metastasis. In human and murine adenocarcinoma and melanoma cell models, including three-dimensional spheroid cultures, we reveal anti-migratory and anti-adhesive properties of adhibin that originate from local disturbances in RhoA/ROCK-regulated signalling, affecting actin-dynamics and actomyosin-based cell-contractility. Adhibin blocks membrane protrusion formation, disturbs remodelling of cell-matrix adhesions, affects contractile ring formation, and disrupts epithelial junction stability; processes severely impairing single/collective cell migration and cytokinesis. Combined with the non-toxic, non-pathological signatures of adhibin validated in organoids, mouse and Drosophila models, this mechanism of action provides the basis for developing anti-metastatic cancer therapies.

Cross-ancestry meta-genome-wide association studies provide insights to the understanding of semen traits in pigs

Semen traits play a crucial role in pig reproduction and fertility. However, limited data availability hinder a comprehensive understanding of the genetic mechanisms underlying these traits. In this study, we integrated 597 299 ejaculates and 3 596 sequence data to identify genetic variants and candidate genes related to four semen traits, including sperm progressive motility (MOT), semen volume, sperm concentration (CON), and effective sperm count (SUM). A cross-ancestry meta-genome-wide association study was conducted to detect 163 lead single nucleotide polymorphisms (SNPs) associated with MOT, CON, and SUM. Subsequently, transcriptome-wide association studies and colocalisation analyses were integrated to identify 176 candidate genes, many of which have documented roles in spermatogenesis or male mammal semen traits. Our analysis highlighted the potential involvement of CSM5, PDZD9, and LDAF1 in regulating semen traits through multiple methods. Finally, to validate the function of significant SNPs, we performed genomic feature best linear unbiased prediction in 348 independent pigs using identified trait-related SNP subsets as genomic features. We found that integrating the top 0.1, 1, and 5% significant SNPs as genomic features could enhance genomic prediction accuracy for CON and MOT compared to traditional genomic best linear unbiased prediction. This study contributes to a comprehensive understanding of the genetic mechanisms of boar semen traits and provides insight for developing genomic selection models.

Aberrant overexpression of myosin 1b in glioblastoma promotes angiogenesis via VEGF-myc-myosin 1b-Piezo1 axis

Glioblastoma (GBM) is the most aggressive intracranial malignancy with poor prognosis. Enhanced angiogenesis is an essential hallmark of GBM, which demonstrates extensive microvascular proliferation and abnormal vasculature. Here, we uncovered the key role of myosin 1b in angiogenesis and vascular abnormality in GBM. Myosin 1b is upregulated in GBM endothelial cells (ECs) compared to the paired nonmalignant brain tissue. In our study, we found that myosin 1b promotes migration, proliferation, and angiogenesis of human/mouse brain ECs. We also found that myosin 1b expression in ECs can be regulated by vascular endothelial growth factor (VEGF) signaling through myc. Moreover, myosin 1b promotes angiogenesis via Piezo1 by enhancing Ca2+ influx, in which process VEGF can be the trigger. In conclusion, our results identified myosin 1b as a key mediator in promoting angiogenesis via mechanosensitive ion channel component 1 (Piezo1) and suggested that VEGF/myc signaling pathway could be responsible for driving the changes of myosin 1b overexpression in GBM ECs.

Divergent iron regulatory states contribute to heterogeneity in breast cancer aggressiveness

Contact with dense collagen I (Col1) can induce collective invasion of triple negative breast cancer (TNBC) cells and transcriptional signatures linked to poor patient prognosis. However, this response is heterogeneous and not well understood. Using phenotype-guided sequencing analysis of invasive vs. noninvasive subpopulations, we show that these two phenotypes represent opposite sides of the iron response protein 1 (IRP1)-mediated response to cytoplasmic labile iron pool (cLIP) levels. Invasive cells upregulate iron uptake and utilization machinery characteristic of a low cLIP response, which includes contractility regulating genes that drive migration. Non-invasive cells upregulate iron sequestration machinery characteristic of a high cLIP response, which is accompanied by upregulation of actin sequestration genes. These divergent IRP1 responses result from Col1-induced transient expression of heme oxygenase I (HO-1), which cleaves heme and releases iron. These findings lend insight into the emerging theory that heme and iron fluxes regulate TNBC aggressiveness.

Emerging concepts of myosin 18A isoform mechanobiology in organismal and immune system physiology, development, and function

Alternative and combinatorial splicing of myosin 18A (MYO18A) gene transcripts results in expression of MYO18A protein isoforms and isoform variants with different membrane and subcellular localizations, and functional properties. MYO18A proteins are members of the myosin superfamily consisting of a myosin-like motor domain, an IQ motif, and a coiled-coil domain. MYO18A isoforms, however, lack the ability to hydrolyze ATP and do not perform ATP-dependent motor activity. MYO18A isoforms are distinguished by different amino- and carboxy-terminal extensions and domains. The domain organization and functions of MYO18Aα, MYO18Aβ, and MYO18Aγ have been studied experimentally. MYO18Aα and MYO18Aβ have a common carboxy-terminal extension but differ by the presence or absence of an amino-terminal KE repeat and PDZ domain, respectively. The amino- and carboxy-terminal extensions of MYO18Aγ contain unique proline and serine-rich domains. Computationally predicted MYO18Aε and MYO18Aδ isoforms contain the carboxy-terminal serine-rich extension but differ by the presence or absence of the amino-terminal KE/PDZ extension. Additional isoform variants within each category arise by alternative utilization or inclusion/exclusion of small exons. MYO18Aα variants are expressed in somatic cells and mature immune cells, whereas MYO18Aβ variants occur mainly in myeloid and natural killer cells. MYO18Aγ expression is selective to cardiac and skeletal muscle. In the present review perspective, we discuss current and emerging concepts of the functional specialization of MYO18A proteins in membrane and cytoskeletal dynamics, cellular communication and signaling, endocytic and exocytic organelle movement, viral infection, and as the SP-R210 receptor for surfactant protein A.

Proteogenomic characterization of difficult-to-treat breast cancer with tumor cells enriched through laser microdissection

BACKGROUND

Breast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer death among women globally. Despite advances, there is considerable variation in clinical outcomes for patients with non-luminal A tumors, classified as difficult-to-treat breast cancers (DTBC). This study aims to delineate the proteogenomic landscape of DTBC tumors compared to luminal A (LumA) tumors.

METHODS

We retrospectively collected a total of 117 untreated primary breast tumor specimens, focusing on DTBC subtypes. Breast tumors were processed by laser microdissection (LMD) to enrich tumor cells. DNA, RNA, and protein were simultaneously extracted from each tumor preparation, followed by whole genome sequencing, paired-end RNA sequencing, global proteomics and phosphoproteomics. Differential feature analysis, pathway analysis and survival analysis were performed to better understand DTBC and investigate biomarkers.

RESULTS

We observed distinct variations in gene mutations, structural variations, and chromosomal alterations between DTBC and LumA breast tumors. DTBC tumors predominantly had more mutations in TP53, PLXNB3, Zinc finger genes, and fewer mutations in SDC2, CDH1, PIK3CA, SVIL, and PTEN. Notably, Cytoband 1q21, which contains numerous cell proliferation-related genes, was significantly amplified in the DTBC tumors. LMD successfully minimized stromal components and increased RNA-protein concordance, as evidenced by stromal score comparisons and proteomic analysis. Distinct DTBC and LumA-enriched clusters were observed by proteomic and phosphoproteomic clustering analysis, some with survival differences. Phosphoproteomics identified two distinct phosphoproteomic profiles for high relapse-risk and low relapse-risk basal-like tumors, involving several genes known to be associated with breast cancer oncogenesis and progression, including KIAA1522, DCK, FOXO3, MYO9B, ARID1A, EPRS, ZC3HAV1, and RBM14. Lastly, an integrated pathway analysis of multi-omics data highlighted a robust enrichment of proliferation pathways in DTBC tumors.

CONCLUSIONS

This study provides an integrated proteogenomic characterization of DTBC vs LumA with tumor cells enriched through laser microdissection. We identified many common features of DTBC tumors and the phosphopeptides that could serve as potential biomarkers for high/low relapse-risk basal-like BC and possibly guide treatment selections.

Are the class 18 myosins Myo18A and Myo18B specialist sarcomeric proteins?

Initially, the two members of class 18 myosins, Myo18A and Myo18B, appeared to exhibit highly divergent functions, complicating the assignment of class-specific functions. However, the identification of a striated muscle-specific isoform of Myo18A, Myo18Aγ, suggests that class 18 myosins may have evolved to complement the functions of conventional class 2 myosins in sarcomeres. Indeed, both genes, Myo18a and Myo18b, are predominantly expressed in the heart and somites, precursors of skeletal muscle, of developing mouse embryos. Genetic deletion of either gene in mice is embryonic lethal and is associated with the disorganization of cardiac sarcomeres. Moreover, Myo18Aγ and Myo18B localize to sarcomeric A-bands, albeit the motor (head) domains of these unconventional myosins have been both deduced and biochemically demonstrated to exhibit negligible ATPase activity, a hallmark of motor proteins. Instead, Myo18Aγ and Myo18B presumably coassemble with thick filaments and provide structural integrity and/or internal resistance through interactions with F-actin and/or other proteins. In addition, Myo18Aγ and Myo18B may play distinct roles in the assembly of myofibrils, which may arise from actin stress fibers containing the α-isoform of Myo18A, Myo18Aα. The β-isoform of Myo18A, Myo18Aβ, is similar to Myo18Aα, except that it lacks the N-terminal extension, and may serve as a negative regulator through heterodimerization with either Myo18Aα or Myo18Aγ. In this review, we contend that Myo18Aγ and Myo18B are essential for myofibril structure and function in striated muscle cells, while α- and β-isoforms of Myo18A play diverse roles in nonmuscle cells.

A liquid biomarker signature of inflammatory proteins accurately predicts early pancreatic cancer progression during FOLFIRINOX chemotherapy

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is often treated with FOLFIRINOX, a chemotherapy associated with high toxicity rates and variable efficacy. Therefore, it is crucial to identify patients at risk of early progression during treatment. This study aims to explore the potential of a multi-omics biomarker for predicting early PDAC progression by employing an in-depth mathematical modeling approach.

METHODS

Blood samples were collected from 58 PDAC patients undergoing FOLFIRINOX before and after the first cycle. These samples underwent gene (GEP) and inflammatory protein expression profiling (IPEP). We explored the predictive potential of exclusively IPEP through Stepwise (Backward) Multivariate Logistic Regression modeling. Additionally, we integrated GEP and IPEP using Bayesian Kernel Regression modeling, aiming to enhance predictive performance. Ultimately, the FOLFIRINOX IPEP (FFX-IPEP) signature was developed.

RESULTS

Our findings revealed that proteins exhibited superior predictive accuracy than genes. Consequently, the FFX-IPEP signature consisted of six proteins: AMN, BANK1, IL1RL2, ITGB6, MYO9B, and PRSS8. The signature effectively identified patients transitioning from disease control to progression early during FOLFIRINOX, achieving remarkable predictive accuracy with an AUC of 0.89 in an independent test set. Importantly, the FFX-IPEP signature outperformed the conventional CA19-9 tumor marker.

CONCLUSIONS

Our six-protein FFX-IPEP signature holds solid potential as a liquid biomarker for the early prediction of PDAC progression during toxic FOLFIRINOX chemotherapy. Further validation in an external cohort is crucial to confirm the utility of the FFX-IPEP signature. Future studies should expand to predict progression under different chemotherapies to enhance the guidance of personalized treatment selection in PDAC.

Divergent iron-regulatory states contribute to heterogeneity in breast cancer aggressiveness

Primary tumors with similar mutational profiles can progress to vastly different outcomes where transcriptional state, rather than mutational profile, predicts prognosis. A key challenge is to understand how distinct tumor cell states are induced and maintained. In triple negative breast cancer cells, invasive behaviors and aggressive transcriptional signatures linked to poor patient prognosis can emerge in response to contact with collagen type I. Herein, collagen-induced migration heterogeneity within a TNBC cell line was leveraged to identify transcriptional programs associated with invasive versus non-invasive phenotypes and implicate molecular switches. Phenotype-guided sequencing revealed that invasive cells upregulate iron uptake and utilization machinery, anapleurotic TCA cycle genes, actin polymerization promoters, and a distinct signature of Rho GTPase activity and contractility regulating genes. The non-invasive cell state is characterized by actin and iron sequestration modules along with glycolysis gene expression. These unique tumor cell states are evident in patient tumors and predict divergent outcomes for TNBC patients. Glucose tracing confirmed that non-invasive cells are more glycolytic than invasive cells, and functional studies in cell lines and PDO models demonstrated a causal relationship between phenotype and metabolic state. Mechanistically, the OXPHOS dependent invasive state resulted from transient HO-1 upregulation triggered by contact with dense collagen that reduced heme levels and mitochondrial chelatable iron levels. This induced expression of low cytoplasmic iron response genes regulated by ACO1/IRP1. Knockdown or inhibition of HO-1, ACO1/IRP1, MRCK, or OXPHOS abrogated invasion. These findings support an emerging theory that heme and iron flux serve as important regulators of TNBC aggressiveness.

Rosmarinic acid in combination with ginsenoside Rg1 suppresses colon cancer metastasis via co-inhition of COX-2 and PD1/PD-L1 signaling axis

Metastasis of colorectal cancer (CRC) is a leading cause of mortality among CRC patients. Elevated COX-2 and PD-L1 expression in colon cancer tissue has been linked to distant metastasis of tumor cells. Although COX-2 inhibitors and immune checkpoint inhibitors demonstrate improved anti-tumor efficacy, their toxicity and variable therapeutic effects in individual patients raise concerns. To address this challenge, it is vital to identify traditional Chinese medicine components that modulate COX-2 and PD-1/PD-L1: rosmarinic acid (RA) exerts striking inhibitory effect on COX-2, while ginsenoside Rg1 (GR) possesses the potential to suppress the binding of PD-1/PD-L1. In this study we investigated whether the combination of RA and GR could exert anti-metastatic effects against CRC. MC38 tumor xenograft mouse model with lung metastasis was established. The mice were administered RA (100 mg·kg-1·d-1, i.g.) alone or in combination with GR (100 mg·kg-1·d-1, i.p.). We showed that RA (50, 100, 150 μM) or a COX-2 inhibitor Celecoxib (1, 3, 9 μM) concentration-dependently inhibited the migration and invasion of MC38 cells in vitro. We further demonstrated that RA and Celecoxib inhibited the metastasis of MC38 tumors in vitro and in vivo via interfering with the COX-2-MYO10 signaling axis and inhibiting the generation of filopodia. In the MC38 tumor xenograft mice, RA administration significantly decreased the number of metastatic foci in the lungs detected by Micro CT scanning; RA in combination with GR that had inhibitory effect on the binding of PD-1 and PD-L1 further suppressed the lung metastasis of colon cancer. Compared to COX-2 inhibitors and immune checkpoint inhibitors, RA and GR displayed better safety profiles without disrupting the tissue structures of the liver, stomach and colon, offering insights into the lower toxic effects of clinical traditional Chinese medicine against tumors while retaining its efficacy.

3D matrix adhesion feedback controls nuclear force coupling to drive invasive cell migration

Cell invasion is a multi-step process, initiated by the acquisition of a migratory phenotype and the ability to move through complex 3D extracellular environments. We determine the composition of cell-matrix adhesion complexes of invasive breast cancer cells in 3D matrices and identify an interaction complex required for invasive migration. βPix and myosin18A (Myo18A) drive polarized recruitment of non-muscle myosin 2A (NM2A) to adhesion complexes at the tips of protrusions. Actomyosin force engagement then displaces the Git1-βPix complex from paxillin, establishing a feedback loop for adhesion maturation. We observe active force transmission to the nucleus during invasive migration that is needed to pull the nucleus forward. The recruitment of NM2A to adhesions creates a non-muscle myosin isoform gradient, which extends from the protrusion to the nucleus. We postulate that this gradient facilitates coupling of cell-matrix interactions at the protrusive cell front with nuclear movement, enabling effective invasive migration and front-rear cell polarity.

Cell stretching activates an ATM mechano-transduction pathway that remodels cytoskeleton and chromatin

Ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) DNA damage response (DDR) kinases contain elastic domains. ATM also responds to reactive oxygen species (ROS) and ATR to nuclear mechanical stress. Mre11 mediates ATM activation following DNA damage; ATM mutations cause ataxia telangiectasia (A-T). Here, using in vivo imaging, electron microscopy, proteomic, and mechano-biology approaches, we study how ATM responds to mechanical stress. We report that cytoskeleton and ROS, but not Mre11, mediate ATM activation following cell deformation. ATM deficiency causes hyper-stiffness, stress fiber accumulation, Yes-associated protein (YAP) nuclear enrichment, plasma and nuclear membrane alterations during interstitial migration, and H3 hyper-methylation. ATM locates to the actin cytoskeleton and, following cytoskeleton stress, promotes phosphorylation of key cytoskeleton and chromatin regulators. Our data contribute to explain some clinical features of patients with A-T and pinpoint the existence of an integrated mechano-response in which ATM and ATR have distinct roles unrelated to their canonical DDR functions.

Whole-exome sequencing of rectal neuroendocrine tumors

The genetic characteristics of rectal neuroendocrine tumors (R-NETs) were poorly understood. Depicting the genetic characteristics may provide a biological basis for prognosis prediction and novel treatment development. Tissues of 18 R-NET patients were analyzed using whole-exome sequencing. The median tumor mutation burden (TMB) and microsatellite instability (MSI) were 1.15 Muts/MB (range, 0.03-23.28) and 0.36 (range, 0.00-10.97), respectively. Genes involved in P53 signaling, PI3K-AKT signaling, DNA damage repair, WNT signaling, etc. were frequently altered. Higher TMB (P = 0.078), higher CNV (P = 0.110), somatic mutation of CCDC168 (P = 0.049), HMCN1 (P = 0.040), MYO10 (P = 0.007), and amplification of ZC3H13 (P < 0.001) were associated with shorter OS. Potentially targetable gene alterations (PTGAs) were seen in 72% of the patients. FGFR1 amplification (22%) was the most common PTGA followed by BARD1 and BRCA2 mutation (each 17%). As for gene variations associated with the efficacy of immune checkpoint blockade (ICB), FAT1 alteration (39%) and PTEN depletion (28%) were commonly observed. In conclusion, frequently altered oncogenic pathways might contribute to the development and progression of R-NETs. Gene alterations significantly associated with prognosis might be potential novel targets. Targeted therapy might be a promising strategy as targetable alterations were prevalent in R-NETs. FAT1 alteration and PTEN depletion might be the main genetic alterations influencing the response to ICB besides overall low TMB and MSI in R-NETs.

A MYCN-independent mechanism mediating secretome reprogramming and metastasis in MYCN-amplified neuroblastoma

MYCN amplification (MNA) is a defining feature of high-risk neuroblastoma (NB) and predicts poor prognosis. However, whether genes within or in close proximity to the MYCN amplicon also contribute to MNA+ NB remains poorly understood. Here, we identify that GREB1, a transcription factor encoding gene neighboring the MYCN locus, is frequently coexpressed with MYCN and promotes cell survival in MNA+ NB. GREB1 controls gene expression independently of MYCN, among which we uncover myosin 1B (MYO1B) as being highly expressed in MNA+ NB and, using a chick chorioallantoic membrane (CAM) model, as a crucial regulator of invasion and metastasis. Global secretome and proteome profiling further delineates MYO1B in regulating secretome reprogramming in MNA+ NB cells, and the cytokine MIF as an important pro-invasive and pro-metastatic mediator of MYO1B activity. Together, we have identified a putative GREB1-MYO1B-MIF axis as an unconventional mechanism promoting aggressive behavior in MNA+ NB and independently of MYCN.

Small extracellular vesicles promote invadopodia activity in glioblastoma cells in a therapy-dependent manner

PURPOSE

The therapeutic efficacy of radiotherapy/temozolomide treatment for glioblastoma (GBM) is limited by the augmented invasiveness mediated by invadopodia activity of surviving GBM cells. As yet, however the underlying mechanisms remain poorly understood. Due to their ability to transport oncogenic material between cells, small extracellular vesicles (sEVs) have emerged as key mediators of tumour progression. We hypothesize that the sustained growth and invasion of cancer cells depends on bidirectional sEV-mediated cell-cell communication.

METHODS

Invadopodia assays and zymography gels were used to examine the invadopodia activity capacity of GBM cells. Differential ultracentrifugation was utilized to isolate sEVs from conditioned medium and proteomic analyses were conducted on both GBM cell lines and their sEVs to determine the cargo present within the sEVs. In addition, the impact of radiotherapy and temozolomide treatment of GBM cells was studied.

RESULTS

We found that GBM cells form active invadopodia and secrete sEVs containing the matrix metalloproteinase MMP-2. Subsequent proteomic studies revealed the presence of an invadopodia-related protein sEV cargo and that sEVs from highly invadopodia active GBM cells (LN229) increase invadopodia activity in sEV recipient GBM cells. We also found that GBM cells displayed increases in invadopodia activity and sEV secretion post radiation/temozolomide treatment. Together, these data reveal a relationship between invadopodia and sEV composition/secretion/uptake in promoting the invasiveness of GBM cells.

CONCLUSIONS

Our data indicate that sEVs secreted by GBM cells can facilitate tumour invasion by promoting invadopodia activity in recipient cells, which may be enhanced by treatment with radio-chemotherapy. The transfer of pro-invasive cargos may yield important insights into the functional capacity of sEVs in invadopodia.

MYO10 regulates genome stability and cancer inflammation through mediating mitosis

Genomic instability can promote inflammation and tumor development. Previous research revealed an unexpected layer of regulation of genomic instability by a cytoplasmic protein MYO10; however, the underlying mechanism remained unclear. Here, we report a protein stability-mediated mitotic regulation of MYO10 in controlling genome stability. We characterized a degron motif and phosphorylation residues in the degron that mediate β-TrCP1-dependent MYO10 degradation. The level of phosphorylated MYO10 protein transiently increases during mitosis, which is accompanied by a spatiotemporal cellular localization change first accumulating at the centrosome then at the midbody. Depletion of MYO10 or expression of MYO10 degron mutants, including those found in cancer patients, disrupts mitosis, increases genomic instability and inflammation, and promotes tumor growth; however, they also increase the sensitivity of cancer cells to Taxol. Our studies demonstrate a critical role of MYO10 in mitosis progression, through which it regulates genome stability, cancer growth, and cellular response to mitotic toxins.

High-Throughput Cellular Heterogeneity Analysis in Cell Migration at the Single-Cell Level

Cancer cell migration represents an essential step toward metastasis and cancer deaths. However, conventional drug discovery focuses on cytotoxic and growth-inhibiting compounds rather than inhibitors of migration. Drug screening assays generally measure the average response of many cells, masking distinct cell populations that drive metastasis and resist treatments. Here, this work presents a high-throughput microfluidic cell migration platform that coordinates robotic liquid handling and computer vision for rapidly quantifying individual cellular motility. Using this innovative technology, 172 compounds were tested and a surprisingly low correlation between migration and growth inhibition was found. Notably, many compounds were found to inhibit migration of most cells while leaving fast-moving subpopulations unaffected. This work further pinpoints synergistic drug combinations, including Bortezomib and Danirixin, to stop fast-moving cells. To explain the observed cell behaviors, single-cell morphological and molecular analysis were performed. These studies establish a novel technology to identify promising migration inhibitors for cancer treatment and relevant applications.

Class I Myosins, molecular motors involved in cell migration and cancer

Class I Myosins are a subfamily of motor proteins with ATPase activity and a characteristic structure conserved in all myosins: A N-Terminal Motor Domain, a central Neck and a C terminal Tail domain. Humans have eight genes for these myosins. Class I Myosins have different functions: regulate membrane tension, participate in endocytosis, exocytosis, intracellular trafficking and cell migration. Cell migration is influenced by many cellular components including motor proteins, like myosins. Recently has been reported that changes in myosin expression have an impact on the migration of cancer cells, the formation of infiltrates and metastasis. We propose that class I myosins might be potential markers for future diagnostic, prognostic or even as therapeutic targets in leukemia and other cancers.Abbreviations: Myo1g: Myosin 1g; ALL: Acute Lymphoblastic Leukemia, TH1: Tail Homology 1; TH2: Tail Homology 2; TH3: Tail Homology 3.

Myo1b promotes tumor progression and angiogenesis by inhibiting autophagic degradation of HIF-1α in colorectal cancer

Myosin 1b (Myo1b) is an important single-headed membrane-associated motor of class I myosins that participate in many critical physiological and pathological processes. Mounting evidence suggests that the dysregulation of Myo1b expression has been extensively investigated in the development and progression of several tumors. However, the functional mechanism of Myo1b in CRC angiogenesis and autophagy progression remains unclear. Herein, we found that the expression of Myo1b was upregulated in CRC tissues and its high expression was correlated with worse survival. The overexpression of Myo1b promoted the proliferation, migration and invasion of CRC cells. Conversely, silencing of Myo1b suppressed tumor progression both in vitro and in vivo. Further studies indicated that Myo1b inhibited the autophagosome-lysosome fusion and potentiated the VEGF secretion of CRC cells to promote angiogenesis. Mechanistically, Myo1b blocked the autophagic degradation of HIF-1α and then led to the accumulation of HIF-1α, thus enhancing VEGF secretion and then promoting tumor angiogenesis in CRC. Together, our study provided novel insights into the role of Myo1b in CRC progression and revealed that it might be a feasible predictive biomarker and promising therapeutic target for CRC patients.

Targeting MYO1B impairs tumorigenesis via inhibiting the SNAI2/cyclin D1 signaling in esophageal squamous cell carcinoma

Myosin‐related proteins play an important role in cancer progression. However, the clinical significance, biological functions, and mechanisms of myosin 1B (MYO1B), in esophageal squamous cell carcinoma (ESCC) remain unclear. The clinical relevance of MYO1B, SNAI2, and cyclin D1 in ESCC was determined by immunohistochemistry, Oncomine, and GEPIA databases. The oncogenic roles of MYO1B were determined by CCK8, colony formation assays, wound healing, and Transwell assay. MYO1B, SNAI2, and cyclin D1 at mRNA and protein levels in ESCC cells were detected by qPCR and Western blot analysis. In our study, we found that MYO1B expression was increased in ESCC tissue samples and correlated with tumor stage, TNM stage, and poor outcomes. Functional assays indicated that depletion of MYO1B impaired oncogenesis, and enhanced chemosensitivity in ESCC. Bioinformatic analysis and mechanistic studies illustrated that SNAI2 was a key downstream effector of MYO1B. Suppression of MYO1B downregulated expression of SNAI2, thereby inhibiting the SNAI2/cyclin D1 pathway. Furthermore, a selective inhibitor of cyclin D1 activation reversed siMYO1B cells overexpressing SNAI2‐elicited aggressive phenotypes of ESCC cells. MYO1B positively correlated with SNAI2 and cyclin D1 in ESCC samples, and higher SNAI2 expression was also associated with poor prognosis in ESCC patients. Our finding demonstrated that MYO1B activates the SNAI2/cyclin D1 pathway to drive tumorigenesis and cisplatin cytotoxicity in ESCC, indicating that MYO1B is a potential therapeutic target for patients with ESCC.

Targeting MYO1B impairs tumorigenesis via inhibiting the SNAI2/cyclin D1 signaling in esophageal squamous cell carcinoma

Myosin-related proteins play an important role in cancer progression. However, the clinical significance, biological functions, and mechanisms of myosin 1B (MYO1B), in esophageal squamous cell carcinoma (ESCC) remain unclear. The clinical relevance of MYO1B, SNAI2, and cyclin D1 in ESCC was determined by immunohistochemistry, Oncomine, and GEPIA databases. The oncogenic roles of MYO1B were determined by CCK8, colony formation assays, wound healing, and Transwell assay. MYO1B, SNAI2, and cyclin D1 at mRNA and protein levels in ESCC cells were detected by qPCR and Western blot analysis. In our study, we found that MYO1B expression was increased in ESCC tissue samples and correlated with tumor stage, TNM stage, and poor outcomes. Functional assays indicated that depletion of MYO1B impaired oncogenesis, and enhanced chemosensitivity in ESCC. Bioinformatic analysis and mechanistic studies illustrated that SNAI2 was a key downstream effector of MYO1B. Suppression of MYO1B downregulated expression of SNAI2, thereby inhibiting the SNAI2/cyclin D1 pathway. Furthermore, a selective inhibitor of cyclin D1 activation reversed siMYO1B cells overexpressing SNAI2-elicited aggressive phenotypes of ESCC cells. MYO1B positively correlated with SNAI2 and cyclin D1 in ESCC samples, and higher SNAI2 expression was also associated with poor prognosis in ESCC patients. Our finding demonstrated that MYO1B activates the SNAI2/cyclin D1 pathway to drive tumorigenesis and cisplatin cytotoxicity in ESCC, indicating that MYO1B is a potential therapeutic target for patients with ESCC.

MYO10 contributes to the malignant phenotypes of colorectal cancer via RACK1 by activating integrin/Src/FAK signaling

Liver metastases still remain a major cause of colorectal cancer (CRC) patient death. MYO10 is upregulated in several tumor types, however, its significance and the underlying mechanism in CRC is not entirely clear. Here we found that MYO10 was highly expressed in CRC tumor tissues, especially in liver metastasis tissues. MYO10 knockout reduced CRC cell proliferation, invasion, and migration in vitro, and CRC metastasis in vivo. We identified RACK1 by LC-MS/MS and demonstrated that MYO10 interacts with and stabilizes RACK1. Mechanistically, MYO10 promotes CRC cell progression and metastasis via ubiquitination-mediated RACK1 degradation and integrin/Src/FAK signaling activation. Therefore, the MYO10/RACK1/integrin/Src/FAK axis may play an important role in CRC progression and metastasis.

A peptide interfering with the dimerization of oncogenic KITENIN protein and its stability suppresses colorectal tumour progression

The stability of a protein, as well as its function and versatility, can be enhanced through oligomerization. KITENIN (KAI1 C-terminal interacting tetraspanin) is known to promote the malignant progression of colorectal cancer (CRC). How KITENIN maintains its structural integrity and stability are largely unknown, however. Here we investigated the mechanisms regulating the stability of KITENIN with the aim of developing therapeutics blocking its oncogenic functions. We found that KITENIN formed a homo-oligomeric complex and that the intracellular C-terminal domain (KITENIN-CTD) was needed for this oligomerization. Expression of the KITENIN-CTD alone interfered with the formation of the KITENIN homodimer, and the amino acid sequence from 463 to 471 within the KITENIN-CTD was the most effective. This sequence coupled with a cell-penetrating peptide was named a KITENIN dimerization-interfering peptide (KDIP). We next studied the mechanisms by which KDIP affected the stability of KITENIN. The KITENIN-interacting protein myosin-X (Myo10), which has oncogenic activity in several cancers, functioned as an effector to stabilize the KITENIN homodimer in the cis formation. Treatment with KDIP resulted in the disintegration of the homodimer via downregulation of Myo10, which led to increased binding of RACK1 to the exposed RACK1-interacting motif (463-471 aa), and subsequent autophagy-dependent degradation of KITENIN and reduced CRC cell invasion. Intravenous injection of KDIP significantly reduced the tumour burden in a syngeneic mouse tumour model and colorectal liver metastasis in an intrasplenic hepatic metastasis model. Collectively, our present results provide a new cancer therapeutic peptide for blocking colorectal liver metastasis, which acts by inducing the downregulation of Myo10 and specifically targeting the stability of the oncogenic KITENIN protein.

Construction of hypoxia-immune-related prognostic model and targeted therapeutic strategies for cervical cancer

Emerging evidence indicates that hypoxia and immunity play important roles in tumorigenesis and development. However, the hypoxia-immune-related prognostic risk model has not been established in cervical cancer (CC). We aimed to construct a hypoxia-immune-based prognostic risk model with potential application in CC patient prognosis and predicting response to targeted therapy. The RNA-seq data and corresponding clinical information were retrieved from The Cancer Genome Atlas (TCGA) database. Hypoxia and immune status of CC patients were evaluated using the Consensus Clustering method and single sample gene set enrichment analysis (ssGSEA), respectively. The univariate Cox regression, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression were applied to establish the prognostic risk model of CC. The chemotherapy response for six chemotherapeutic agents of each CC patient was calculated according to the Genomics of Drug Sensitivity in Cancer (GDSC). And the Connectivity Map (CMap) database was performed to screen candidate small molecule drugs. In this study, we identified 7 gene signatures (P4HA2, MSMO1, EGLN1, ZNF316, IKZF3, ISCU, MYO1B) with prognostic values. And the survival time of patients with low-risk was significantly longer than those with high-risk. Meanwhile, CC patients in the high-risk group yielded higher sensitivity to five chemotherapeutic agents. And we listed ten candidate small-molecules drugs that exhibited a high correlation with the prognosis of cervical cancer. Thus, the prognostic model can accurately predict the prognosis of patients with CC and may be helpful for the development of new hypoxia-immune prognostic markers and therapeutic strategies for CC.

Comprehensive Landscape of Prognostic Significance and Immune Characteristics of Myosins in Squamous Cell Carcinoma of the Head and Neck

Myosin superfamily, a large and diverse family of molecular motors important for cell motility and migration, has been illustrated to play contradictory roles during the development of several kinds of tumors. However, the function and prognostic values of MYOs in head and neck squamous cell carcinoma (HNSCC) still remain largely unknown. In the current manuscript, the expression levels and clinical data of MYOs in HNSCC were investigated by online databases, including Oncomine, GEPIA, GEO, TCGA, HPA, UALCAN, Kaplan-Meier plotter, and CancerSEA; we found that the expression levels of MYO1B, MYO5A, and MYO10 were significantly elevated in HNSCC tissues, which were also correlated with the unfavorable overall survival (OS) of the patients. Furthermore, MYO1B/MYO5A/MYO10 interacting genes were identified, and the protein-protein interaction (PPI) networks were constructed by STRING and GeneMANIA. The enrichment analysis revealed that MYO1B/MYO5A/MYO10 associated genes mainly participated in cell metastasis and EMT processes, which were also confirmed by cell functional experiments. At last, the ssGSEA method was conducted to investigate the extent of immune cell infiltration, and we found that both the expression of MYO1B/MYO5A/MYO10 were closely correlated with the infiltration of immune cells in HNSCC. These findings implied that MYO1B, MYO5A, and MYO10 as novel prognostic factors for HNSCC and provided new strategy for HNSCC treatment.

Turning Platelets Off and On: Role of RhoGAPs and RhoGEFs in Platelet Activity

Platelet cytoskeletal reorganisation is a critical component of platelet activation and thrombus formation in haemostasis. The Rho GTPases RhoA, Rac1 and Cdc42 are the primary drivers in the dynamic reorganisation process, leading to the development of filopodia and lamellipodia which dramatically increase platelet surface area upon activation. Rho GTPases cycle between their active (GTP-bound) and inactive (GDP-bound) states through tightly regulated processes, central to which are the guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). GEFs catalyse the dissociation of GDP by inducing changes in the nucleotide binding site, facilitating GTP binding and activating Rho GTPases. By contrast, while all GTPases possess intrinsic hydrolysing activity, this reaction is extremely slow. Therefore, GAPs catalyse the hydrolysis of GTP to GDP, reverting Rho GTPases to their inactive state. Our current knowledge of these proteins is constantly being updated but there is considerably less known about the functionality of Rho GTPase specific GAPs and GEFs in platelets. In the present review, we discuss GAP and GEF proteins for Rho GTPases identified in platelets, their regulation, biological function and present a case for their further study in platelets.

MYO1B enhances colorectal cancer metastasis by promoting the F-actin rearrangement and focal adhesion assembly via RhoA/ROCK/FAK signaling

Background

Colorectal cancer (CRC) has a high worldwide incidence and mortality. Tumor metastasis is one of the primary reasons for the poor prognosis of CRC patients. However, the mechanism underlying CRC metastasis is still unclear. Myosin 1B (MYO1B) is important for cell migration and motility and is part of the myosin superfamily that contains various myosins. Studies of prostate, cervical, and head and neck cancer have revealed preliminary findings concerning the effect of MYO1B on tumor metastasis. However, the role of MYO1B in CRC metastasis, as well as its underlying mechanism, remains unknown.

Methods

Quantitative real-time PCR and immunohistochemical staining methods were used to analyze the expression of MYO1B in human CRC and normal mucosa tissues. Lentivirus vector-based MYO1B oligonucleotides and short hairpin RNA (shRNA) were used to examine the functional relevance of MYO1B in CRC cells. Co-immunoprecipitation, western blotting, and immunofluorescence assays were used to investigate the underlying mechanism of MYO1B-mediated cell migration.

Results

The expression of MYO1B was increased in most CRC tissues and was positively associated with a greater risk of tumor metastasis and poor prognosis for patients. MYO1B was significantly associated with the migration and invasion properties of CRC cells in vitro and in vivo. MYO1B promoted F-actin rearrangement through the ROCK2/LIMK/Cofilin axis by enhancing the activation of RhoA. MYO1B also promoted the assembly of focal adhesions by targeting RhoA.

Conclusions

MYO1B plays a vital role in CRC metastasis by promoting the activation of RhoA. MYO1B may not only be a valid biomarker for predicting the risk of metastasis and poor prognosis in CRC but may also be a potential therapeutic target for patients with a high risk of tumor metastasis.

Myosin 1b promotes migration, invasion and glycolysis in cervical cancer via ERK/HIF-1α pathway

BACKGROUND

Increasing evidence indicated that metabolic reprograming is essential and has been regarded as a hallmark of cancer. Although the biological functions of Myosin 1b (Myo1b) have been reported in several malignancies, the correlation between Myo1b and cancer metabolism, and its underlying mechanisms remain elusive, particularly in cervical cancer (CC).

METHODS

Myo1b and other glycolytic enzymes expression levels were examined in CC cells and tumor tissues from xenograft models by quantitative real-time PCR, Western blot and immunohistochemistry. The biological impacts and regulatory mechanisms of Myo1b on cell migration, invasion and glycolysis were explored. Also, the effects of Myo1b on carcinogenesis and metastasis in nude mice were investigated.

RESULTS

Upregulation of Myo1b was found in CC tissues and associated with poor prognosis. Overexpressed Myo1b not only significantly elevated CC cell glycolysis, migration and invasion in vitro, but also promoted tumorigenesis and metastasis in vivo. Conversely, Myo1b knockdown had opposite consequences. Moreover, our study suggested that Myo1b stimulated ERK/HIF-1α pathway and its downstream glycolysis associated genes to modulate the glycolysis, migration and invasion of CC.

CONCLUSION

These findings provide evidence that Myo1b regulates migration, invasion and glycolysis in CC through ERK/HIF-1α pathway, suggesting a promising remedial target in treatment of CC.

Nonmuscle Myosin II in cancer cell migration and mechanotransduction

Cell migration is a key step of cancer metastasis, immune-cell navigation, homing of stem cells and development. What adds complexity to it is the heterogeneity of the tissue environment that gives rise to a vast diversity of migratory mechanisms utilized by cells. A majority of cell motility mechanisms reported elsewhere largely converge in depicting the importance of the activity and complexity of actomyosin networks in the cell. In this review, we highlight the less discussed functional diversity of these actomyosin complexes and describe in detail how the major cellular actin-binding molecular motor proteins, nonmuscle myosin IIs are regulated and how they participate and mechanically reciprocate to changes in the microenvironment during cancer cell migration and tumor progression. Understanding the role of nonmuscle myosin IIs in the cancer cell is important for designing efficient therapeutic strategies to prevent cancer metastasis.

Ion channels as key partners of cytoskeleton in cancer disease

Several processes occur during tumor development including changes in cell morphology, a reorganization of the expression and distribution of the cytoskeleton proteins as well as ion channels. If cytoskeleton proteins and ion channels have been widely investigated in understanding cancer mechanisms, the interaction between these two elements and the identification of the associated signaling pathways are only beginning to emerge. In this review, we summarize the work published over the past 15 years relating to the roles played by ion channels in these mechanisms of reorganization of the cellular morphology, essential to metastatic dissemination, both through the physical interactions with elements of the cytoskeleton and by intracellular signaling pathways involved.

A metastasis suppressor Pt-dendrimer nanozyme for the alleviation of glioblastoma

Nanozymes are nanostructure-based materials which mimic the enzymatic characteristics of natural enzymes. Biological applications of nanozymes have been highlighted in basic research, industry, and translational medicine as a new cutting-edge tool. In this work, and for the first time, we disclose a tumor alleviation property of a nanozyme that is made up of amine-terminated sixth-generation polyamidoamine dendrimers with encapsulated tiny platinum nanoparticles. We systematically conducted the synthesis and characterization of the dendrimer-encapsulated Pt nanoparticles (denoted Pt-dendrimer) and confirmed their enzymatic function (hydrogen peroxide (H2O2) decomposition) within various cell lines (normal, cancerous), including glioblastoma (GBM) cells. By understanding the effects of the Pt-dendrimer at the gene level, especially related to cancer cell metastasis, we have thoroughly demonstrated its ability for tumor alleviation and suppressing GBM migration, invasion, and adhesion. The present findings show great promise for the application of the nanozyme for use in GBM-related basic research as well as at clinical sites.

Pharmacologically targeting molecular motor promotes mitochondrial fission for anti-cancer

Mitochondrial shape rapidly changes by dynamic balance of fusion and fission to adjust to constantly changing energy demands of cancer cells. Mitochondrial dynamics balance is exactly regulated by molecular motor consisted of myosin and actin cytoskeleton proteins. Thus, targeting myosin-actin molecular motor is considered as a promising strategy for anti-cancer. In this study, we performed a proof-of-concept study with a natural-derived small-molecule J13 to test the feasibility of anti-cancer therapeutics via pharmacologically targeting molecular motor. Here, we found J13 could directly target myosin-9 (MYH9)-actin molecular motor to promote mitochondrial fission progression, and markedly inhibited cancer cells survival, proliferation and migration. Mechanism study revealed that J13 impaired MYH9-actin interaction to inactivate molecular motor, and caused a cytoskeleton-dependent mitochondrial dynamics imbalance. Moreover, stable isotope labeling with amino acids in cell culture (SILAC) technology-coupled with pulldown analysis identified HSPA9 as a crucial adaptor protein connecting MYH9-actin molecular motor to mitochondrial fission. Taken together, we reported the first natural small-molecule directly targeting MYH9-actin molecular motor for anti-cancer translational research. Besides, our study also proved the conceptual practicability of pharmacologically disrupting mitochondrial fission/fusion dynamics in human cancer therapy.

Multifaceted Function of Myosin-18, an Unconventional Class of the Myosin Superfamily

Myosin is a diverse superfamily of motor proteins responsible for actin-based motility and contractility in eukaryotic cells. Myosin-18 family, including myosin-18A and myosin-18B, belongs to an unconventional class of myosin, which lacks ATPase motor activity, and the investigations on their functions and molecular mechanisms in vertebrate development and diseases have just been initiated in recent years. Myosin-18A is ubiquitously expressed in mammalian cells, whereas myosin-18B shows strong enrichment in striated muscles. Myosin-18 family is important for cell motility, sarcomere formation, and mechanosensing, mostly by interacting with other cytoskeletal proteins and cellular apparatus. Myosin-18A participates in several intracellular transport processes, such as Golgi trafficking, and has multiple roles in focal adhesions, stress fibers, and lamellipodia formation. Myosin-18B, on the other hand, participates in actomyosin alignment and sarcomere assembly, thus relating to cell migration and muscle contractility. Mutations of either Myo18a or Myo18b cause cardiac developmental defects in mouse, emphasizing their crucial role in muscle development and cardiac diseases. In this review, we revisit the discovery history of myosin-18s and summarize the evolving understanding of the molecular functions of myosin-18A and myosin-18B, with an emphasis on their separate yet closely related functions in cell motility and contraction. Moreover, we discuss the diseases tightly associated with myosin-18s, especially cardiovascular defects and cancer, as well as highlight the unanswered questions and potential future research perspectives on myosin-18s.

Myosin 10 Regulates Invasion, Mitosis, and Metabolic Signaling in Glioblastoma

Invasion and proliferation are defining phenotypes of cancer, and in glioblastoma blocking one stimulates the other, implying that effective therapy must inhibit both, ideally through a single target that is also dispensable for normal tissue function. The molecular motor myosin 10 meets these criteria. Myosin 10 knockout mice can survive to adulthood, implying that normal cells can compensate for its loss; its deletion impairs invasion, slows proliferation, and prolongs survival in murine models of glioblastoma. Myosin 10 deletion also enhances tumor dependency on the DNA damage and the metabolic stress responses and induces synthetic lethality when combined with inhibitors of these processes. Our results thus demonstrate that targeting myosin 10 is active against glioblastoma by itself, synergizes with other clinically available therapeutics, may have acceptable side effects in normal tissues, and has potential as a heretofore unexplored therapeutic approach for this disease.

Characterization and validation of long noncoding RNAs as new candidates in prostate cancer

Background

Long noncoding RNAs (lncRNAs) have been proved to be an important regulator in gene expression. In almost all kinds of cancers, lncRNAs participated in the process of pathogenesis, invasion, and metastasis. Meanwhile, compared with the large amounts of patients, there is rare knowledge about the role of lncRNAs in prostate cancer (PCa).

Material/Method

In this study, lncRNA expression profiles of prostate cancer were detected by Agilent microarray chip, 5 pairs of case and control specimens were involved in. Differentially expressed lncRNAs were screened out by volcano plot for constructing lncRNA-miRNA-mRNA central network. Then, the top ten up-regulated and down-regulated lncRNAs were validated by qRT-PCR in another 5 tumor specimens and 7 para-cancerous/benign contrasts. Furthermore, we searched for the survival curve of the top 10 upregulated and downregulated lncRNAs.

Results

A total of 817 differentially expressed lncRNAs were filtered out by the criteria of fold change (FC) and t-test p < 0.05. Among them, 422 were upregulated, whereas 395 were downregulated in PCa tissues. Gene ontology and KEGG pathway analyses showed that many lncRNAs were implicated in carcinogenesis. lnc-MYL2-4:1 (FC = 0.00141, p = 0.01909) and NR_125857 (FC = 59.27658, p = 0.00128) had the highest magnitude of change. The subsequent qPCR confirmed the expression of NR_125857 was in accordance with the clinical samples. High expression of PCA3, PCAT14 and AP001610.9 led to high hazard ratio while low expression of RP11-279F6.2 led to high hazard ratio.

Conclusions

Our study detected a relatively novel complicated map of lncRNAs in PCa, which may have the potential to investigate for diagnosis, treatment and follow-up in PCa. Our study revealed the expression of NR_125857 in human PCa tissues was most up-regulated. Further studies are needed to investigate to figure out the mechanisms in PCa.

Intratumor Heterogeneity of MYO18A and FBXW7 Variants Impact the Clinical Outcome of Stage III Colorectal Cancer

Many studies failed to demonstrate benefit from the addition of targeted agents to current standard adjuvant FOLFOX chemotherapy in stage III colorectal cancer (CRC) patients. Intratumor heterogeneity may foster the resistant subclones and leads to cancer recurrence. Here, we built a cancer evolution model and applied machine learning analysis to identify potential therapeutic targets. Among 78 CRC cases, whole-genome (WGS) and deep targeted sequencing data generated from paired blood and primary tumor were used for phylogenetic tree reconstruction. Genetic alterations in the PI3K/AKT, and RTK oncogenic signaling pathways were commonly detected in founding clones. The dominant subclones frequently exhibited dysregulations in the TP53, FBXW7/NOTCH1 tumor suppression, and DNA repair pathways. Fourteen genetic mutations were simultaneously selected by random forest and LASSO methods. The logistic regression model had better accuracy (79%), precision (70%), and recall (65%) and area under the curve (AUC) (82%) for cancer recurrence prediction. Three genes, including MYO18A in the founding clone, FBXW7, and ATM in the dominant subclone, affected the prognosis were selected simultaneously by different feature sets. The in vitro studies, HCT-116 cells transfected with MYO18A siRNA demonstrated a significant reduction in cell migration activity by 20-40%. These results indicate that MYO18A plays a crucial role in the migration of human CRC cells. The cancer evolution model revealed the critical mutations in the founding and dominant subclones. They can be used to predict clinical outcomes and the development of novel therapeutic targets for stage III CRC.

Truncation of MYH8 tail in AML: a novel prognostic marker with increase cell migration and epithelial-mesenchymal transition utilizing RAF/MAPK pathway

MYH8 is an actin-based motor protin involved in integrin-mediated cell adhesion and migration. Heretofore, the association of MYH8 mutation and cancer is unclear. In this study, we investigated the biologic significance of novel MYH8 tail truncation mutation, R1292X, in acute myeloid leukemia (AML) which was discovered by whole-exome sequencing and targeted re-sequencing of 209 AML patients. The patients harboring the mutation all relapsed within 3.8-20.9 months. To explore the functional consequence of the mutation in AML progress, we established knock-in cell lines using CRISPR-Cas9 genome editing. Using the established mutant model, we assessed traits of cancer progress. The mutant cells had improved motility, which was confirmed by immunofluorescence staining, wound healing, transwell migration and adhesion assay. The cell morphology and cell cycle were altered to be accessible to migration and epithelial-to-mesenchymal transition (EMT) transcription factors were also increased. The Raf and p44/42 MAPK pathway was a major regulator of these characteristics proved by a screening of signal transduction and inhibitor assay. Further, a public cancer genome database (cBioPortal) shows that MYH8 tail truncation mutations occurring near the R1292 position of the genome may have a significant function in cancer. In conclusion, truncation of MYH8 could be a novel prognostic marker related to poor prognosis by inducing cell migration and EMT features, and inhibition of the Raf/MAPK pathway would be a therapeutic strategy for AML patients with MYH8 tail truncation.

TSAd Plays a Major Role in Myo9b-Mediated Suppression of Malignant Pleural Effusion by Regulating TH1/TH17 Cell Response

Emerging evidence indicates that Myo9b is a cancer metastasis-related protein and functions in a variety of immune-related diseases. However, it is not clear whether and how Myo9b functions in malignant pleural effusion (MPE). In this study, our data showed that Myo9b expression levels correlated with lung cancer pleural metastasis, and nucleated cells in MPE from either patients or mice expressed a lower level of Myo9b than those in the corresponding blood. Myo9b deficiency in cancer cells suppressed MPE development via inhibition of migration. Myo9b deficiency in mice suppressed MPE development by decreasing T_H1 cells and increasing T_H17 cells. CD4⁺ naive T cells isolated from Myo9b^-/- mouse spleens exhibited less T_H1 cell differentiation and more T_H17 cell differentiation in vitro. mRNA sequencing of nucleated cells showed that T cell-specific adaptor protein (TSAd) was downregulated in Myo9b^-/- mouse MPE, and enrichment of the H3K27me3 mark in the TSAd promoter region was found in the Myo9b^-/- group. Naive T cells purified from wild type mouse spleens transfected with TSAd-specific small interfering RNAs (siRNAs) also showed less T_H1 cell differentiation and more T_H17 cell differentiation than those from the siRNA control group. Furthermore, downregulation of TSAd in mice using cholesterol-conjugated TSAd-specific siRNA suppressed MPE development, decreased T_H1 cells, and increased T_H17 cells in MPE in vivo. Taken together, Myo9b deficiency suppresses MPE development not only by suppressing pleural cancer metastasis but also by regulating T_H1/T_H17 cell response via a TSAd-dependent pathway. This work suggests Myo9b and TSAd as novel candidates for future basic and clinical investigations of cancer.

Study and detection of potential markers for predicting metastasis into lymph nodes in prostate cancer

Hormone-refractory prostate carcinoma has a different cell surface protein profile than hormone-sensitive prostate carcinoma, which provides migration ability and interactions with organs/tissues. Detection and association of these proteins with lymph node metastasis via lymphadenectomy might be beneficial for patients. Gene expression analysis in hormone-refractory and hormone-sensitive commercial cancer cell lines was performed and, after co-cultivation with osteoblasts or endothelial cells, knockdown experiments followed to validate potential biomarkers. "Myeloid-associated differentiation markers, myosin 1b and phosphatidylinositol-4-phosphate-5-kinase type 1 alpha are implicated in metastasis", their knockdown altered the expression of key regulators of endothelial-mesenchymal transition, invasion, motility and migration. In primary prostate tumors, these genes could be an indicator for future metastasis into lymph nodes.

Omental macrophages secrete chemokine ligands that promote ovarian cancer colonization of the omentum via CCR1

The omentum is the most common site of ovarian cancer metastasis. Immune cell clusters called milky spots are found throughout the omentum. It is however unknown if these immune cells contribute to ovarian cancer metastasis. Here we report that omental macrophages promote the migration and colonization of ovarian cancer cells to the omentum through the secretion of chemokine ligands that interact with chemokine receptor 1 (CCR1). We found that depletion of macrophages reduces ovarian cancer colonization of the omentum. RNA-sequencing of macrophages isolated from mouse omentum and mesenteric adipose tissue revealed a specific enrichment of chemokine ligand CCL6 in omental macrophages. CCL6 and the human homolog CCL23 were both necessary and sufficient to promote ovarian cancer migration by activating ERK1/2 and PI3K pathways. Importantly, inhibition of CCR1 reduced ovarian cancer colonization. These findings demonstrate a critical mechanism of omental macrophage induced colonization by ovarian cancer cells via CCR1 signaling.

Krishnan et al. find that CCR1 ligands CCL6 and CCL23 secreted by murine and human macrophages, respectively, enhance metastatic colonization of ovarian cancer cells to the omentum in manner dependent on chemokine receptor 1 (CCR1). This study suggests that targeting CCR1 or CCL23 in ovarian cancer may be a therapeutic strategy.

Myosins and Disease

Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.