miR-183-5p overexpression orchestrates collective invasion in salivary adenoid cystic carcinoma through the FAT1/YAP1 signaling pathway.

The invasion of cancer cells into interstitial tissues in a cohesive unit is termed collective invasion, and it is important for the invasion and metastasis of salivary adenoid cystic carcinoma (SACC). However, the underlying mechanisms regulating SACC collective invasion are still poorly understood. Here, we found that SACC tissues exhibited remarkable FAT1 downregulation and YAP1 upregulation at the invasive front, which was closely associated with collective invasion and distant metastasis. Decreasing FAT1 expression significantly activated the YAP1 signaling pathway and promoted collective invasion. Moreover, miR-183-5p was identified as the candidate regulator of FAT1 by bioinformatic analysis and an online database algorithm. A dual luciferase reporter experiment further confirmed that miR-183-5p directly targeted the FAT1 3'-UTR to reduce FAT1 expression. Increasing or decreasing miR-183-5p expression promoted or attenuated collective invasion, which was reversed by YAP1 siRNA or FAT1 siRNA, respectively. In addition, knocking down miR-183-5p reduced tumor burden and attenuated collective invasion in vivo. Together, these results suggest that the miR-183-5p/FAT1/YAP1 signaling pathway is a critical driver of SACC collective invasion, revealing a novel therapeutic target.

Artemisinin suppressed tumour growth and induced vascular normalisation in oral squamous cell carcinoma via inhibition of macrophage migration inhibitory factor.

BACKGROUND: Tumour vascular normalisation therapy advocates a balance between pro-angiogenic factors and anti-angiogenic factors in tumours. Artemisinin (ART), which is derived from traditional Chinese medicine, has been shown to inhibit tumour growth; however, the relationship between ART and tumour vascular normalisation in oral squamous cell carcinoma (OSCC) has not been previously reported. METHODS: Different concentrations(0 mg/kg, 25 mg/kg, 50 mg/kg, 100 mg/kg)of ART were used to treat the xenograft nude mice model of OSCC. The effects of ART on migration and proliferation of OSCC and human umbilical vein endothelial cells (HUVEC) cells were detected by scratch assay and CCK-8 assay. OSCC cells with macrophage migration inhibitory factor (MIF) silenced were constructed to explore the effect of MIF. RESULTS: Treatment with ART inhibited the growth and angiogenesis of OSCC xenografts in nude mice and downregulated vascular endothelial growth factor (VEGF), IL-8, and MIF expression levels. ART reduced the proliferation, migration, and tube formation of HUVEC, as well as the expression of VEGFR1 and VEGFR2. When the dose of ART was 50 mg/kg, vascular normalisation of OSCC xenografts was induced. Moreover, VEGF and IL-8 were needed in rhMIF restoring tumour growth and inhibit vascular normalisation after the addition of rhMIF to ART-treated cells. CONCLUSION: Artemisinin might induce vascular normalisation and inhibit tumour growth in OSCC through the MIF-signalling pathway.

[Corrigendum] Dll4/Notch1 signalling pathway is required in collective invasion of salivary adenoid cystic carcinoma.

Following the publication of this article, the authors have realized that they made an error during the compilation of the images shown in Fig. 6, and that this error was not corrected before the paper was sent to press. Specifically, in Fig. 6B, the data panels showing the results from the HUVEC + SACC­83 si­Dll4 and HUVEC + SACC­LM si­Dll4 experiments at 24 h were inadvertently repeated. The corrected version of Fig. 6, showing the correctly assembled data panels for Fig. 6B, is shown on the next page. The authors sincerely apologize for the errors that were introduced during the preparation of this Figure, thank the Editor for allowing them the opportunity to publish this Corrigendum, and regret any inconvenience that these errors may have caused. [the original article was published in Oncology Reports 45: 1011­1022, 2021; DOI: 10.3892/or.2021.7939].

Insight Into the Molecular Mechanism of Podophyllotoxin Derivatives as Anticancer Drugs.

Podophyllotoxin (PTOX) is a biologically active compound derived from the podophyllum plant, and both it and its derivatives possess excellent antitumor activity. The PTOX derivatives etoposide (VP-16) and teniposide (VM-26) have been approved by the U.S. Food and Drug Administration (FDA) for cancer treatment, but are far from perfect. Hence, numerous PTOX derivatives have been developed to address the major limitations of PTOX, such as systemic toxicity, drug resistance, and low bioavailability. Regarding their anticancer mechanism, extensive studies have revealed that PTOX derivatives can induce cell cycle G2/M arrest and DNA/RNA breaks by targeting tubulin and topoisomerase II, respectively. However, few studies are dedicated to exploring the interactions between PTOX derivatives and downstream cancer-related signaling pathways, which is reasonably important for gaining insight into the role of PTOX. This review provides a comprehensive analysis of the role of PTOX derivatives in the biological behavior of tumors and potential molecular signaling pathways, aiming to help researchers design and develop better PTOX derivatives.

CXCL12/CXCR4 facilitates perineural invasion via induction of the Twist/S100A4 axis in salivary adenoid cystic carcinoma.

The activation of CXCL12/CXCR4 axis participated in the progression of multiple cancers, but potential effect in terms of perineural invasion (PNI) in SACC remained ambiguous. In this study, we identified that CXCL12 substantially expressed in nerve cells. CXCR4 strikingly expressed in tumour cells, and CXCR4 expression was closely associated with the level of EMT-associated proteins and Schwann cell hallmarks at nerve invasion frontier in SACC. Activation of CXCL12/CXCR4 axis could promote PNI and up-regulate relative genes of EMT and Schwann cell hallmarks both in vitro and in vivo, which could be inhibited by Twist silence. After overexpressing S100A4, the impaired PNI ability of SACC cells induced by Twist knockdown was significantly reversed, and pseudo foot was visualized frequently. Collectively, the results indicated that CXCL12/CXCR4 might promote PNI by provoking the tumour cell to differentiate towards Schwann-like cell through Twist/S100A4 axis in SACC.

CXCR5 induces perineural invasion of salivary adenoid cystic carcinoma by inhibiting microRNA-187.

CXCR5 played critical roles in tumorigenesis and metastasis. Nevertheless, little was known about the involvement of CXCR5 in perineural invasion (PNI) of salivary adenoid cystic carcinoma (SACC). Here, we confirmed upregulation of CXCR5 in SACC specimens and cells and identified that CXCR5 exhibited a significant positive correlation with PNI. Functionally, knockdown of CXCR5 suppressed SACC cells migration, invasion and PNI ability, whereas CXCR5 overexpression displayed the opposite effects. Moreover, CXCR5 downregulated microRNA (miR)-187, which could competitively sponge S100A4. The PNI-inhibitory effect of CXCR5 knockdown or miR-187 overexpression could be reversed by elevated expression of S100A4. Conjointly, our data revealed that CXCR5 facilitated PNI through downregulating miR-187 to disinhibit S100A4 expression in SACC.

Dll4/Notch1 signalling pathway is required in collective invasion of salivary adenoid cystic carcinoma.

High expression of δ­like ligand 4 (Dll4) is reportedly related to the invasion, metastasis, and clinical prognosis of various malignant tumours. Our previous study revealed that collective cell invasion was a common pattern in salivary adenoid cystic carcinoma (SACC). However, the roles of the Dll4/Notch1 signalling pathway in the collective invasion of SACC remain unclear. The present study revealed that Dll4 expression was higher at the invasive front of SACC, and that this upregulation was associated with solid tumour type, high TNM grade, and high rates of metastasis and recurrence. Furthermore, the expression levels of Notch1 and Dll4 were positively correlated at the invasive front, and a three­dimensional (3D) culture model revealed that leader cells showed high expression of Dll4, while follower cells showed high expression of Notch1. Moreover, silencing of Dll4 expression using small interfering RNA reduced the migration, invasion, and collective invasion of SACC cells, and these abilities were rescued by Notch1 overexpression. Finally, SACC collective invasion was increased via the Dll4/Notch1 signalling pathway in experiments that involved a stiff 3D gel, hypoxia and co­culture with human endothelial cells. These findings indicated that the Dll4/Notch1 signalling pathway may be involved in the collective invasion of SACC, which may help to provide possible targets for the treatment of SACC.

Plasticity of cancer cell invasion: Patterns and mechanisms.

Cancer cell migration and invasion are integral components of metastatic disease, which is the major cause of death in cancer patients. Cancer cells can disseminate and migrate via several alternative mechanisms including amoeboid cell migration, mesenchymal cell migration, and collective cell migration. These diverse movement strategies display certain specific and distinct hallmarks in cell-cell junctions, actin cytoskeleton, matrix adhesion, and protease activity. During tumor progression, cells pass through complex microenvironments and adapt their migration strategies by reversible mesenchymal-amoeboid and individual-collective transitions. This plasticity in motility patterns enables cancer cells disseminate further and thus limit the efficiency of anti-metastasis therapies. In this review, we discuss the modes and mechanisms of cancer cell migration and focus on the plasticity of tumor cell movement as well as potential emerging therapeutic options for reducing cancer cell invasion.

What makes leader cells arise: Intrinsic properties and support from neighboring cells.

Cancer cells collectively invading as a cohesive and polarized group is termed collective invasion, which is a fundamental property of many types of cancers. In this multicellular unit, cancer cells are heterogeneous, consisting of two morphologically and functionally distinct subpopulations, leader cells and follower cells. Leader cells at the invasive front are responsible for exploring the microenvironment, paving the way, and transmitting information to follower cells. Here, in this review, we will describe the important role of leader cells in collective invasion and the emerging underlying mechanisms of leader cell formation including intrinsic properties and the support from neighboring cells. It will help us to elucidate the essence of collective invasion and provide new anticancer therapeutic clues.

What makes cells move: Requirements and obstacles for leader cells in collective invasion.

Most recently, mounting evidence has shown that cancer cells can invade as a cohesive and multicellular group with coordinated movement, which is called collective invasion. In this cohesive cancer cell group, cancer cells at the front of collective invasion are defined as leader cell that are responsible for many aspects of collective invasion, including sensing the microenvironment, determining the invasion direction, modifying the path of invasion and transmitting information to other cells. To fulfill their dispensable roles, leader cells are required to embark on some specific phenotypes with unusual expression of some proteins and it's very important to investigate into these proteins as they may serve as potential therapeutic targets. Here, in this review we will summarize current knowledge on four emerging proteins highly expressed in leader cells including K14, ΔNp63α, Dll4 and cysteine protease cathepsin B (CTSB), with a focus on their important roles in collective invasion and special mechanisms by which they promote collective invasion.

Activation of necroptosis in a rat model of acute respiratory distress syndrome induced by oleic acid.

The present study was aimed to investigate the role of necroptosis in the pathogenesis of acute respiratory distress syndrome (ARDS). The rat model of ARDS was induced by intravenous injection of oleic acid (OA), and observed for 4 h. The lung injury was evaluated by arterial blood gas, lung wet-dry weight ratio (W/D) and histological analyses. Simultaneously, bronchoalveolar lavage fluid (BALF) was collected for total and differential cell analysis and total protein determination. Tumor necrosis factor alpha (TNF-α) level in BALF was determined with a rat TNF-α ELISA kit. Expressions of receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like protein (MLKL) in lung tissue were determined by Western blot and immunohistochemical staining. The interaction between RIPK1 and RIPK3 was explored by immunoprecipitation. The results showed that, compared with those in control group, total white blood cells count (WBC), polymorphonuclear percentage (PMN%), total protein concentration, TNF-α level in BALF, W/D, and the alveolar-arterial oxygen tension difference (P(A-a)O2) in OA group were significantly increased at 4 h after OA injection. Western blot and immunostaining further showed remarkably increased expressions of RIPK1, RIPK3 and MLKL in lung tissue from OA group. Additionally, immunoprecipitation results indicated an enforced interaction between RIPK1 and RIPK3 in OA group. Collectively, the TNF-α level in BALF and the RIPK1-RIPK3-MLKL signaling pathway in lung tissue were found to be upregulated and activated with the process of ARDS. These findings implicate that RIPK1/RIPK3-mediated necroptosis plays a possible role in the pathogenesis of ARDS, which may provide a new idea to develop novel drugs for the therapy of ARDS.

Necrostatin-1 protects against oleic acid-induced acute respiratory distress syndrome in rats.

Necroptosis is a recently discovered necrotic cell death which is regulated by receptor interacting protein kinase 1 (RIPK1) and RIPK3 under the stimulus of death signal and can be inhibited by necrostatin-1 (Nec-1) specifically. Therefore, the aim was to investigate the role of necroptosis in a rat model of acute respiratory distress syndrome (ARDS) induced by oleic acid (OA) and assess the effect of Nec-1 on lung injury in ARDS. Our results found that RIPK1, RIPK3 and mixed lineage kinase domain-like protein (MLKL) were abundantly expressed in rat lung tissues of OA-induced ARDS. Nec-1 pretreatment improved pulmonary function and attenuated lung edema dramatically in OA-induced ARDS rats. Furthermore, Nec-1 reduced RIPK1-RIPK3 interaction and down-regulated RIPK1-RIPK3-MLKL signal pathway, and inhibited inflammatory response by reducing neutrophil infiltration and protein leakage into lung tissue in OA-induced ARDS. Collectively, our study proves the intervention of necroptosis in OA-induced ARDS. Moreover, our findings imply that Nec-1 plays an important role in the treatment of ARDS via inhibiting necroptosis and inflammation.

Evaluation of liver function and electroacupuncture efficacy of animals with alcoholic liver injury by the novel imaging methods.

Imaging methods to evaluate hepatic microcirculation (HM) and liver function (LF) by directly monitoring overall liver tissue remain lacking. This study establish imaging methods for LF that combines Laser speckle perfusion imaging (LSPI) and in vivo optical imaging (IVOI) technologies to investigate changes of hepatic microcirculation and reserve function in the animals gavaged with 50% ethanol (15 ml/kg·bw) for a model of acute alcoholic liver injury (ALI), and for evaluation of electroacupuncture (EA) effect. The liver blood perfusion and indocyanine green (ICG) distribution were observe by LSPI and IVOI separately. After EA, the livers were collected to measure the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), thromboxane A (TXA2), prostacyclin (PGI2) and endothelin (ET). The acquisitions of newly established LSPI of liver and ICG in vivo fluorescence imaging (ICG-IVFI), combining the results of other indexes showed: hepatic microcirculation perfusion (HMP) significantly reduced, ICG metabolism reduced, and ALT/AST increased in animal model with acute ALI. EA can reverse these changes. The use of LSPI of liver and ICG-IVFI, which was novel imaging methods for LF established in this study, could display the LF characteristics of ALI and the EA efficacy.

[Effect of electroacupuncture of "Taichong" (LR 3) on liver function in mild alcoholic liver injury rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of "Taichong" (LR 3) on liver function in rats with mild alcoholic liver injury (MALI) so as to explore the feasibility of acupuncture in improving mild alcoholic liver injury. METHODS: Forty SD rats were randomly divided into control, model, EA-LR 3 and EA-non-acupoint groups (10 rats/group). MALI model was duplicated by intragastric administration of distillate spirit (14 mL/kg) for 12 hours. Rats of the control group were fed with the same volume of normal saline. EA (2 Hz, 6 V) was applied to bilateral "Taichong" (LR 3) and non-acupoint (the interspace between the 4th and 5th bones of toes in parallel with LR 3) for 30 min, respectively. At the end of experiments, rats were sacrificed for collecting liver tissues. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) of the liver supernatant were detected by using Lai's method. RESULTS: IIn comparison with the control group, liver ALT and AST activities in the model group were increased significantly (P < 0.05), while in comparison with the model group, liver ALT and AST levels in the EA-LR 3 group were down-regulated remarkably (P < 0.05). No significant changes were found in liver ALT and AST level in the EA-non-acupoint group (P > 0.05). There was no significant improvement in the pathological changes of liver in the EA-LR 3 and EA-non-acupoint groups. CONCLUSION: EA of "Taichong"(LR 3) may reduce distillate-spirit induced mild alcoholic liver injury in rats.