Dynamin2 GTPase contributes to invadopodia formation in invasive bladder cancer cells

Nuclear Expression of Dynamin 2 Is Associated With Tumor Aggressiveness in Bladder Cancer Patients: A Bioinformatics and Experimental Approach

BACKGROUND

Dynamin 2 (DNM2) is aberrantly expressed in different malignancies and exerts a function in tumor progression.

AIMS

This study, for the first time, aimed to evaluate the clinical and prognostic value of DNM2 in the pathophysiology of bladder cancer using bioinformatics analysis and experimental evaluation.

METHODS AND RESULTS

We analyzed gene expression of DNM2 in bladder tumor by GEPIA2 and GENT2 platforms. Cluster subnetworks were recognized from the protein-protein interaction (PPI) network using the MCODE plugin to screen the key genes. Subsequently, the pathway enrichment analysis was evaluated. Then, the immunohistochemical examination was conducted on 209 paraffin-embedded bladder cancer samples to determine the expression pattern and clinical importance of DNM2. Our data mining findings demonstrated dysregulation of DNM2 gene expression in bladder cancer. The results of pathway and PPI network analyses indicated that DNM2 might be involved in the development of bladder cancer by influencing various signaling pathways. Our IHC results represented remarkably higher DNM2 expression in bladder tumor samples compared to normal tissue samples adjacent to tumor. A statistically significant association was identified between DNM2 expression in the nucleus and higher histological grade (p = 0.026), advanced pT stage (p = 0.016), muscular invasion (p = 0.007), tumor recurrence (p = 0.030), and distant metastasis (p < 0.001). Moreover, the nuclear DNM2 expression was observed to have prognostic significance for disease-specific survival (DSS) using a log-rank test (p = 0.028).

CONCLUSION

These findings suggest that nuclear DNM2 expression could be a putative indicator of bladder tumor progression owing to its association with elevated cancer aggressiveness.

The host GTPase Dynamin 2 modulates apical junction structure to control cell-to-cell spread of Listeria monocytogenes

The food-borne pathogen Listeria monocytogenes uses actin-based motility to generate plasma membrane protrusions that mediate the spread of bacteria between host cells. In polarized epithelial cells, efficient protrusion formation by L. monocytogenes requires the secreted bacterial protein InlC, which binds to a carboxyl-terminal Src homology 3 (SH3) domain in the human scaffolding protein Tuba. This interaction antagonizes Tuba, thereby diminishing cortical tension at the apical junctional complex and enhancing L. monocytogenes protrusion formation and spread. Tuba contains five SH3 domains apart from the domain that interacts with InlC. Here, we show that human GTPase Dynamin 2 associates with two SH3 domains in the amino-terminus of Tuba and acts together with this scaffolding protein to control the spread of L. monocytogenes. Genetic or pharmacological inhibition of Dynamin 2 or knockdown of Tuba each restored normal protrusion formation and spread to a bacterial strain deleted for the inlC gene (∆inlC). Dynamin 2 localized to apical junctions in uninfected human cells and protrusions in cells infected with L. monocytogenes. Localization of Dynamin 2 to junctions and protrusions depended on Tuba. Knockdown of Dynamin 2 or Tuba diminished junctional linearity, indicating a role for these proteins in controlling cortical tension. Infection with L. monocytogenes induced InlC-dependent displacement of Dynamin 2 from junctions, suggesting a possible mechanism of antagonism of this GTPase. Collectively, our results show that Dynamin 2 cooperates with Tuba to promote intercellular tension that restricts the spread of ∆inlC Listeria. By expressing InlC, wild-type L. monocytogenes overcomes this restriction.

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.

Cancer-specific apoptosis induction in canine lymphoma cell lines by the endocytosis inhibitor dynasore

Canine lymphoma is the most common cancer in dogs and has a poor prognosis. We recently found that the endocytosis inhibitor dynasore suppresses the viability of human cancer cell lines, especially hematopoietic cancers, by inducing apoptosis. In the present study, we examined the anticancer effects of dynasore on five previously established canine lymphoma cell lines (CLBL-1, Ema, Nody-1, CLC, and GL-1). Dynasore suppressed cell viability in these canine lymphoma cell lines more effectively than in human cancer cell lines. It also induced apoptosis in CLBL-1 and Ema cells but not in peripheral blood mononuclear cells in healthy dogs or in Madin-Darby canine kidney (MDCK) cells, suggesting that the ability of dynasore to induce apoptosis is cancer-specific. Furthermore, dynasore induced a DNA damage response in CLBL-1 and Ema cells, suggesting that it acts as a genotoxic agent in canine lymphoma cell lines. These findings suggest that endocytosis inhibitors may provide a new anticancer treatment for canine lymphoma.

The endocytosis inhibitor dynasore induces a DNA damage response pathway that can be manipulated for enhanced apoptosis

Endocytosis has been shown to play an important role in cancer proliferation and metastasis. Recent studies have accumulated evidence that endocytosis inhibitors suppress in vitro and in vivo proliferation and migration. In addition, endocytosis inhibition has been shown to induce apoptosis, but its mechanism remains largely unclear. In this study, we found that the endocytosis inhibitor dynasore causes a cell viability reduction in multiple cancer cell lines, especially in hematopoietic cancers. Dynasore induced massive apoptosis and an S-phase progression delay. In addition, dynasore activated the ATR-Chk1 DNA damage response, which suggests a single-stranded DNA exposure induced by DNA replication stress. Furthermore, an ATR inhibitor sensitized the dynasore-induced apoptosis. These findings suggest that endocytosis inhibitors may have an ability to suppress DNA replication, a common mechanism of genotoxic chemotherapies targeting cancer, and that the anti-cancer effects of endocytosis inhibitors may be sensitized by DNA damage response inhibitors.

ERRα Up-Regulates Invadopodia Formation by Targeting HMGCS1 to Promote Endometrial Cancer Invasion and Metastasis

Estrogen-related receptor alpha (ERRα) plays an important role in endometrial cancer (EC) progression. However, the biological roles of ERRα in EC invasion and metastasis are not clear. This study aimed to investigate the role of ERRα and 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) in regulating intracellular cholesterol metabolism to promote EC progression. ERRα and HMGCS1 interactions were detected by co-immunoprecipitation, and the effects of ERRα/HMGCS1 on the metastasis of EC were investigated by wound-healing and transwell chamber invasion assays. Cellular cholesterol content was measured to verify the relationship between ERRα and cellular cholesterol metabolism. Additionally, immunohistochemistry was performed to confirm that ERRα and HMGCS1 were related to EC progression. Furthermore, the mechanism was investigated using loss-of-function and gain-of-function assays or treatment with simvastatin. High expression levels of ERRα and HMGCS1 promoted intracellular cholesterol metabolism for invadopodia formation. Moreover, inhibiting ERRα and HMGCS1 expression significantly weakened the malignant progression of EC in vitro and in vivo. Our functional analysis showed that ERRα promoted EC invasion and metastasis through the HMGCS1-mediated intracellular cholesterol metabolism pathway, which was dependent on the epithelial-mesenchymal transition pathway. Our findings suggest that ERRα and HMGCS1 are potential targets to suppress EC progression.

IKAROS in Acute Leukemia: A Positive Influencer or a Mean Hater?

One key process that controls leukemogenesis is the regulation of oncogenic gene expression by transcription factors acting as tumor suppressors. Understanding this intricate mechanism is crucial to elucidating leukemia pathophysiology and discovering new targeted treatments. In this review, we make a brief overview of the physiological role of IKAROS and the molecular pathway that contributes to acute leukemia pathogenesis through IKZF1 gene lesions. IKAROS is a zinc finger transcription factor of the Krüppel family that acts as the main character during hematopoiesis and leukemogenesis. It can activate or repress tumor suppressors or oncogenes, regulating the survival and proliferation of leukemic cells. More than 70% of Ph+ and Ph-like cases of acute lymphoblastic leukemia exhibit IKZF1 gene variants, which are linked to worse treatment outcomes in both childhood and adult B-cell precursor acute lymphoblastic leukemia. In the last few years, much evidence supporting IKAROS involvement in myeloid differentiation has been reported, suggesting that loss of IKZF1 might also be a determinant of oncogenesis in acute myeloid leukemia. Considering the complicated "social" network that IKAROS manages in hematopoietic cells, we aim to focus on its involvement and the numerous alterations of molecular pathways it can support in acute leukemias.

Updates on the Pivotal Roles of Mitochondria in Urothelial Carcinoma

Mitochondria are important organelles responsible for energy production, redox homeostasis, oncogenic signaling, cell death, and apoptosis. Deregulated mitochondrial metabolism and biogenesis are often observed during cancer development and progression. Reports have described the crucial roles of mitochondria in urothelial carcinoma (UC), which is a major global health challenge. This review focuses on research advances in the role of mitochondria in UC. Here, we discuss the pathogenic roles of mitochondria in UC and update the mitochondria-targeted therapies. We aim to offer a better understanding of the mitochondria-modulated pathogenesis of UC and hope that this review will allow the development of novel mitochondria-targeted therapies.

Development of versatile allele-specific siRNAs able to silence all the dominant dynamin 2 mutations

Dominant centronuclear myopathy (CNM) is a rare form of congenital myopathy associated with a wide clinical spectrum, from severe neonatal to milder adult forms. There is no available treatment for this disease due to heterozygous mutations in the DNM2 gene encoding Dynamin 2 (DNM2). Dominant DNM2 mutations also cause rare forms of Charcot-Marie-Tooth disease and hereditary spastic paraplegia, and deleterious DNM2 overexpression was noticed in several diseases. The proof of concept for therapy by allele-specific RNA interference devoted to silence the mutated mRNA without affecting the normal allele was previously achieved in a mouse model and patient-derived cells, both expressing the most frequent DNM2 mutation in CNM. In order to have versatile small interfering RNAs (siRNAs) usable regardless of the mutation, we have developed allele-specific siRNAs against two non-pathogenic single-nucleotide polymorphisms (SNPs) frequently heterozygous in the population. In addition, allele-specific siRNAs against the p.S619L DNM2 mutation, a mutation frequently associated with severe neonatal cases, were developed. The beneficial effects of these new siRNAs are reported for a panel of defects occurring in patient-derived cell lines. The development of these new molecules allows targeting the large majority of the patients harboring DNM2 mutations or overexpression by only a few siRNAs.

Overexpression of cytoplasmic dynamin 2 is associated with worse outcomes in patients with clear cell renal cell carcinoma

BACKGROUND: Dynamin 2 (DNM2) involved in tumor progression in various malignancies. OBJECTIVE: For the first time, we evaluated DNM2 expression pattern, its association with clinicopathological characteristics and survival outcomes in RCC subtypes. METHODS: We evaluated the DNM2 expression pattern in RCC tissues as well as adjacent normal tissue using immunohistochemistry on tissue microarray (TMA) slides. RESULTS: Our findings revealed increased DNM2 expression in RCC samples rather than in adjacent normal tissues. The results indicated that there was a statistically significant difference between cytoplasmic expression of DNM2 among subtypes of RCC in terms of intensity of staining, percentage of positive tumor cells, and H-score (P= 0.024, 0.049, and 0.009, respectively). The analysis revealed that increased cytoplasmic expression of DNM2 in ccRCC is associated with worse OS (log rank: P= 0.045), DSS (P= 0.049), and PFS (P= 0.041). Furthermore, cytoplasmic expression of DNM2 was found as an independent prognostic factor affecting DSS and PFS in multivariate analysis. CONCLUSIONS: Our results indicated that DNM2 cytoplasmic expression is associated with tumor aggressiveness and poor outcomes. DNM2 could serve as a promising prognostic biomarker and therapeutic target in patients with ccRCC.

Dynamin 2 and BAR domain protein pacsin 2 cooperatively regulate formation and maturation of podosomes

Podosomes are actin-rich adhesion structures formed in a variety of cell types, such as monocytic cells or cancer cells, to facilitate attachment to and degradation of the extracellular matrix (ECM). Previous studies showed that dynamin 2, a large GTPase involved in membrane remodeling and actin organization, is required for podosome function. However, precise roles of dynamin 2 at the podosomes remain to be elucidated. In this study, we identified a BAR (Bin-Amphiphysin-Rvs167) domain protein pacsin 2 as a functional partner of dynamin 2 at podosomes. Dynamin 2 and pacsin 2 interact and co-localize to podosomes in Src-transformed NIH 3T3 (NIH-Src) cells. RNAi of either dynamin 2 or pacsin 2 in NIH-Src cells inhibited podosome formation and maturation, suggesting essential and related roles at podosomes. Consistently, RNAi of pacsin 2 prevented dynamin 2 localization to podosomes, and reciprocal RNAi of dynamin 2 prevented pacsin 2 localization to podosomes. Taking these results together, we conclude that dynamin 2 and pacsin 2 co-operatively regulate organization of podosomes in NIH-Src cells.

A review of Dynamin 2 involvement in cancers highlights a promising therapeutic target

Dynamin 2 (DNM2) is an ubiquitously expressed large GTPase well known for its role in vesicle formation in endocytosis and intracellular membrane trafficking also acting as a regulator of cytoskeletons. During the last two decades, DNM2 involvement, through mutations or overexpression, emerged in an increasing number of cancers and often associated with poor prognosis. A wide panel of DNM2-dependent processes was described in cancer cells which explains DNM2 contribution to cancer pathomechanisms. First, DNM2 dysfunction may promote cell migration, invasion and metastasis. Second, DNM2 acts on intracellular signaling pathways fostering tumor cell proliferation and survival. Relative to these roles, DNM2 was demonstrated as a therapeutic target able to reduce cell proliferation, induce apoptosis, and reduce the invasive phenotype in a wide range of cancer cells in vitro. Moreover, proofs of concept of therapy by modulation of DNM2 expression was also achieved in vivo in several animal models. Consequently, DNM2 appears as a promising molecular target for the development of anti-invasive agents and the already provided proofs of concept in animal models represent an important step of preclinical development.

Identification of Potential Chemical Substrates as Fuel for Hypoxic Tumors That May Be Linked to Invadopodium Formation in Hypoxia-Induced MDA-MB-231 Breast-Cancer Cell Line

Hypoxia plays a significant role in solid tumors by the increased expression of hypoxia-inducible factor-1α (HIF-1α), which is known to promote cancer invasion and metastasis. Cancer-cell invasion dynamically begins with the degradation of the extracellular matrix (ECM) via invadopodia formation. The chemical substrates that are utilized by hypoxic cells as fuel to drive invadopodia formation are still not fully understood. Therefore, the aim of the study was to maintain MDA-MB-231 cells under hypoxia conditions to allow cells to form a large number of invadopodia as a model, followed by identifying their nutrient utilization. The results of the study revealed an increase in the number of cells forming invadopodia under hypoxia conditions. Moreover, Western blot analysis confirmed that essential proteins for hypoxia and invadopodia, including HIF-1α, vascular endothelial growth factor (VEGF), metallopeptidase-2 (MMP-2), and Rho guanine nucleotide exchange factor 7 (β-PIX), significantly increased under hypoxia. Interestingly, phenotype microarray showed that only 11 chemical substrates from 367 types of substrates were significantly metabolized in hypoxia compared to in normoxia. This is thought to be fuel for hypoxia to drive the invasion process. In conclusion, we found 11 chemical substrates that could have potential energy sources for hypoxia-induced invadopodia formation of these cells. This may in part be a target in the hypoxic tumor and invadopodia formation. Additionally, these findings can be used as potential carrier targets in cancer-drug discovery, such as the usage of dextrin.

Dynamin 2 Is Correlated with Recurrence and Poor Prognosis of Papillary Thyroid Cancer

Background

Papillary thyroid cancer (PTC) is the most common histological type of thyroid cancer. Most PTC patients have favorable outcomes, but 10% of patients still have distant metastases at presentation or during follow-up. Dynamin 2 (DNM2) is the only DNM ubiquitously expressed in human tissues, but its expression and clinical significance in PTC is still unknown.

Material/Methods

In our study, we investigated the expression of DNM2 in 112 cases of PTC and classified the patients into low and high expression of DNM2. The clinical significance of DNM2 was evaluated by assessing its correlation with the clinicopathological parameters with the chi-square method. The correlations between DNM2 expression and the disease-free survival rate or overall survival rate were assessed with the Kaplan-Meier method and the log-rank test. The independent prognostic factors of PTC were determined by the Cox-regression hazard model.

Results

Patients with low and high DNM2 expression accounted for 75% and 25% respectively in the 112 patients with PTC. High DNM2 expression was significantly associated with recurrence (P=0.014) and poor prognosis (P=0.004). In addition to tumor stage, DNM2 expression was an independent prognostic biomarker of PTC, indicating an unfavorable prognosis.

Conclusions

DNM2 was an independent PTC biomarker indicating more likely recurrence and poorer prognosis. Detecting DNM2 expression may help to select the high-risk patients for adjuvant therapy.

Mitochondria in cancer

The rediscovery and reinterpretation of the Warburg effect in the year 2000 occulted for almost a decade the key functions exerted by mitochondria in cancer cells. Until recent times, the scientific community indeed focused on constitutive glycolysis as a hallmark of cancer cells, which it is not, largely ignoring the contribution of mitochondria to the malignancy of oxidative and glycolytic cancer cells, being Warburgian or merely adapted to hypoxia. In this review, we highlight that mitochondria are not only powerhouses in some cancer cells, but also dynamic regulators of life, death, proliferation, motion and stemness in other types of cancer cells. Similar to the cells that host them, mitochondria are capable to adapt to tumoral conditions, and probably to evolve to ‘oncogenic mitochondria' capable of transferring malignant capacities to recipient cells. In the wider quest of metabolic modulators of cancer, treatments have already been identified targeting mitochondria in cancer cells, but the field is still in infancy.

Dynamin 2 interacts with α-actinin 4 to drive tumor cell invasion

The large GTPase Dynamin 2 (Dyn2) is known to increase the invasiveness of pancreatic cancer tumor cells, but the mechanisms by which Dyn2 regulates changes in the actin cytoskeleton to drive cell migration are still unclear. Here we report that a direct interaction between Dyn2 and the actin-bundling protein alpha-actinin (α-actinin) 4 is critical for tumor cell migration and remodeling of the extracellular matrix in pancreatic ductal adenocarcinoma (PDAC) cells. The direct interaction is mediated through the C-terminal tails of both Dyn2 and α-actinin 4, and these proteins interact at invasive structures at the plasma membrane. While Dyn2 binds directly to both α-actinin 1 and α-actinin 4, only the interaction with α-actinin 4 is required to promote tumor cell invasion. Specific disruption of the Dyn2-α-actinin 4 interaction blocks the ability of PDAC cells to migrate in either two dimensions or invade through extracellular matrix as a result of impaired invadopodia stability. Analysis of human PDAC tumor tissue additionally reveals that elevated α-actinin 4 or Dyn2 expression are predictive of poor survival. Overall, these data demonstrate that Dyn2 regulates cytoskeletal dynamics, in part, by interacting with the actin-binding protein α-actinin 4 during tumor cell invasion.

Transcriptional Regulation of Genes by Ikaros Tumor Suppressor in Acute Lymphoblastic Leukemia

Regulation of oncogenic gene expression by transcription factors that function as tumor suppressors is one of the major mechanisms that regulate leukemogenesis. Understanding this complex process is essential for explaining the pathogenesis of leukemia as well as developing targeted therapies. Here, we provide an overview of the role of Ikaros tumor suppressor and its role in regulation of gene transcription in acute leukemia. Ikaros (IKZF1) is a DNA-binding protein that functions as a master regulator of hematopoiesis and the immune system, as well as a tumor suppressor in acute lymphoblastic leukemia (ALL). Genetic alteration or functional inactivation of Ikaros results in the development of high-risk leukemia. Ikaros binds to the specific consensus binding motif at upstream regulatory elements of its target genes, recruits chromatin-remodeling complexes and activates or represses transcription via chromatin remodeling. Over the last twenty years, a large number of Ikaros target genes have been identified, and the role of Ikaros in the regulation of their expression provided insight into the mechanisms of Ikaros tumor suppressor function in leukemia. Here we summarize the role of Ikaros in the regulation of the expression of the genes whose function is critical for cellular proliferation, development, and progression of acute lymphoblastic leukemia.

MiR-612 regulates invadopodia of hepatocellular carcinoma by HADHA-mediated lipid reprogramming

Background

MicroRNA-612 (miR-612) has been proven to suppress EMT, stemness, and tumor metastasis of hepatocellular carcinoma (HCC) via PI3K/AKT2 and Sp1/Nanog signaling. However, its biological roles on HCC progression are far from elucidated.

Methods

We found direct downstream target of miR-612, hadha by RNA immunoprecipitation and sequencing. To explore its biological characteristic, potential molecular mechanism, and clinical relevance in HCC patients, we performed several in-vitro and in-vivo models, as well as human tissue chip.

Results

Ectopic expression of miR-612 could partially reverse the level of HADHA, then suppress function of pseudopods, and diminish metastatic and invasive potential of HCC by lipid reprogramming. In detail, miR-612 might reduce invadopodia formation via HADHA-mediated cell membrane cholesterol alteration and accompanied with the inhibition of Wnt/β-catenin regulated EMT occurrence. Our results showed that the maximum oxygen consumption rates (OCR) of HCCLM3^miR-612-OE and HCCLM3^hadha-KD cells were decreased nearly by 40% and 60% of their counterparts (p < 0.05). The levels of acetyl CoA were significantly decreased, about 1/3 (p > 0.05) or 1/2 (p < 0.05) of their controls, in exogenous miR-612 or hadha-shRNA transfected HCCLM3 cell lines. Besides, overexpression of hadha cell lines had a high expression level of total cholesterol, especially 27-hydroxycholesterol (p < 0.005). SREBP2 protein expression level as well as its downstream targets, HMGCS1, HMGCR, MVD, SQLE were all deregulated by HADHA. Meanwhile, the ATP levels were reduced to 1/2 and 1/4 in HCCLM3^miR-612-OE (p < 0.05) and HCCLM3^hadha-KD (p < 0.01) respectively. Moreover, patients with low miR-612 levels and high HADHA levels had a poor prognosis with shorter overall survival.

Conclusion

miR-612 can suppress the formation of invadopodia, EMT, and HCC metastasis and by HADHA-mediated lipid programming, which may provide a new insight of miR-612 on tumor metastasis and progression.

Caveolin-1 and dynamin-2 overexpression is associated with the progression of bladder cancer

Caveolae-mediated endocytosis regulates cell adhesion and growth in an anchorage-dependent manner. Studies of the endocytic function of caveolae have suggested a wide-ranging list of cargoes, including a number of receptors and extracellular proteins, ligands and nutrients from the extracellular matrix. Disruption of the processes of caveolae-mediated endocytosis mediated by signaling proteins is critical to cellular integrity. Caveolin-1 and dynamin-2 are the 2 major proteins associated with endocytotic function. Mechanistically, dynamin-2 has a co-equal role with caveolin-1 in terms of caveolae-derived endosome formation. Recent studies have revealed the pathological outcomes associated with the dysregulation of caveolin-1 and dynamin-2 expression. Increased expression levels of the gene for caveolin, Cav-1, resulting in augmented cellular metastasis and invasion, have been demonstrated in various types of cancer, and overexpression of the gene for dynamin-2, DNM2, has been associated with tumorigenesis in cervical, pancreatic and lung cancer. An increased expression of Cav-1 and DNM2 is known to be associated with the invasive behavior of cancer cells, and with cancer progression. Furthermore, it has been previously demonstrated that, in caveolar assembly and caveolae mediated endocytosis, Cav-1 interacts directly with DNM2 during the processes. Altered expression of the 2 genes is critical for the normal function of the cell. The expression patterns of Cav-1 and DNM2 have been previously examined in bladder cancer cell lines, and were each demonstrated to be overexpressed. In the present study, the expression levels of these 2 genes in bladder cancer samples were quantified. The gene expression levels of Cav-1 and DNM2 were identified to be increased 8.88- and 8.62-fold, respectively, in tumors compared with the normal controls. Furthermore, high-grade tumors exhibited significantly increased expression levels of Cav-1 and DNM2 (both P<0.0001) compared with the low-grade tumors. In addition, compared with normal control samples, the expression of the 2 genes in tumor samples was observed to be highly significant (P<0.0001), with a marked positive correlation identified for the tumors (Pearson's correlation coefficient, r=0.80 for the tumor samples vs. r=0.32 in the normal control samples). Taken together, the results of the present study demonstrated that the overexpression of Cav-1 and DNM2 genes, and a determination of their correlation coefficients, may be a potential risk factor for bladder cancer, in addition to other clinical factors.

Cortactin and fascin-1 regulate extracellular vesicle release by controlling endosomal trafficking or invadopodia formation and function

Cancer cell-derived extracellular vesicles (EVs) are increasingly being recognized as genuine invasive structures as they contribute to many aspects of invasion and metastasis. Unfortunately, the mechanisms underlying EV biogenesis or release are still poorly understood. Recent reports however indicate a role of the actin cytoskeleton in this process. In this study, we have exploited thoroughly characterized camelid nanobodies against actin binding proteins cortactin and fascin-1, a branched actin regulator and actin bundler, respectively, in order to assess their roles in EV biogenesis or release. Using this strategy, we demonstrate a role of the cortactin NTA and SH3 domains in EV release. Fascin-1 also regulates EV release, independently of its actin-bundling activity. We show a contribution of these protein domains in endosomal trafficking, a crucial step in EV biogenesis, and we confirm that EVs are preferentially released at invadopodia, the latter being actin-rich invasive cell protrusions in which cortactin and fascin-1 perform essential roles. Accordingly, EVs are enriched with invadopodial proteins such as the matrix metalloproteinase MT1-MMP and exert gelatinolytic activity. Based on our findings, we report that both cortactin and fascin-1 play key roles in EV release by regulating endosomal trafficking or invadopodia formation and function.

A bi-specific inhibitor targeting IL-17A and MMP-9 reduces invasion and motility in MDA-MB-231 cells

The cytokine IL-17A is associated with the progression of various cancers, but little is known about the molecular cross-talk between IL-17A and other tumor-promoting factors. Previous studies have shown that the IL-17A-mediated invasion of breast cancer cells can be inhibited by selective antagonists of the matrix metalloproteinase 9 (MMP-9), suggesting that the cross-talk between IL-17A and MMP-9 may promote cancer invasiveness and metastasis. Here, we present a novel strategy for developing cancer therapeutics, based on the simultaneous binding and inhibition of both IL-17A and MMP-9. To this end, we use a bi-specific heterodimeric fusion protein, comprising a natural inhibitor of MMPs (N-TIMP2) fused with an engineered extracellular domain (V3) of the IL-17A receptor. We show that, as compared with the mono-specific inhibitors of IL-17A (V3) and MMP-9 (N-TIMP2), the engineered bi-specific fusion protein inhibits both MMP-9 activation and IL-17A-induced cytokine secretion from fibroblasts and exhibits a synergistic inhibition of both the migration and invasion of breast cancer cells. Our findings demonstrate, for the first time, that dual targeting of inflammatory (IL-17A) and extracellular matrix remodeling (MMP) pathways can potentially be used as a novel therapeutic approach against cancer. Moreover, the platform developed here for generating the bi-specific IL-17A/MMP-9 inhibitor can be utilized for generating bi-specific inhibitors for other cytokines and MMPs.

Distinct functions of dynamin isoforms in tumorigenesis and their potential as therapeutic targets in cancer

Dynamins and their related proteins participate in the regulation of neurotransmission, antigen presentation, receptor internalization, growth factor signalling, nutrient uptake, and pathogen infection. Recently, emerging findings have shown dynamin proteins can also contribute to the genesis of cancer. This up-to-date review herein focuses on the functionality of dynamin in cancer development. Dynamin 1 and 2 both enhance cancer cell proliferation, tumor invasion and metastasis, whereas dynamin 3 has tumor suppression role. Antisense RNAs encoded on the DNA strand opposite a dynamin gene regulate the function of dynamin, and manipulate oncogenes and tumor suppressor genes. Certain dynamin-related proteins are also upregulated in distinct cancer conditions, resulting in apoptotic resistance, cell migration and poor prognosis. Altogether, dynamins are potential biomarkers as well as representing promising novel therapeutic targets for cancer treatment. This study also summarizes the current available dynamin-targeted therapeutics and suggests the potential strategy based on signalling pathways involved, providing important information to aid the future development of novel cancer therapeutics by targeting these dynamin family members.