Targeting p21-activated kinase 1 inhibits growth and metastasis via Raf1/MEK1/ERK signaling in esophageal squamous cell carcinoma cells

Effects of FGF2 Priming and Nrf2 Activation on the Antioxidant Activity of Several Human Dental Pulp Cell Clones Derived From Distinct Donors, and Therapeutic Effects of Transplantation on Rodents With Spinal Cord Injury

In recent years, the interest in cell transplantation therapy using human dental pulp cells (DPCs) has been increasing. However, significant differences exist in the individual cellular characteristics of human DPC clones and in their therapeutic efficacy in rodent models of spinal cord injury (SCI); moreover, the cellular properties associated with their therapeutic efficacy for SCI remain unclear. Here, using DPC clones from seven different donors, we found that most of the clones were highly resistant to H2O2 cytotoxicity if, after transplantation, they significantly improved the locomotor function of rats with complete SCI. Therefore, we examined the effects of the basic fibroblast growth factor 2 (FGF2) and bardoxolone methyl (RTA402), which is a nuclear factor erythroid 2-related factor 2 (Nrf2) chemical activator, on the total antioxidant capacity (TAC) and the resistance to H2O2 cytotoxicity. FGF2 treatment enhanced the resistance of a subset of clones to H2O2 cytotoxicity. Regardless of FGF2 priming, RTA402 markedly enhanced the resistance of many DPC clones to H2O2 cytotoxicity, concomitant with the upregulation of heme oxygenase-1 (HO-1) and NAD(P)H-quinone dehydrogenase 1 (NQO1). With the exception of a subset of clones, the TAC was not increased by either FGF2 priming or RTA402 treatment alone, whereas it was significantly upregulated by both treatments in each clone, or among all seven DPC clones together. Thus, the TAC and resistance to H2O2 cytotoxicity were, to some extent, independently regulated and were strongly enhanced by both FGF2 priming and RTA402 treatment. Moreover, even a DPC clone that originally exhibited no therapeutic effect on SCI improved the locomotor function of mice with SCI after transplantation under both treatment regimens. Thus, combined with FGF2, RTA402 may increase the number of transplanted DPCs that migrate into and secrete neurotrophic factors at the lesion epicenter, where reactive oxygen species are produced at a high level.

TrCla4 promotes actin polymerization at the hyphal tip and mycelial growth in Trichophyton rubrum

IMPORTANCE

Superficial fungal infections, such as athlete's foot, affect more than 10% of the world's population and have a significant impact on quality of life. Despite the fact that treatment-resistant fungi are a concern, there are just a few antifungal drug targets accessible, as opposed to the wide range of therapeutic targets found in bacterial infections. As a result, additional alternatives are sought. In this study, we generated a PAK TrCla4 deletion strain (∆Trcla4) of Trichophyton rubrum. The ∆Trcla4 strain exhibited deficiencies in mycelial growth, hyphal morphology, and polarized actin localization at the hyphal tip. IPA-3 and FRAX486, small chemical inhibitors of mammalian PAK, were discovered to limit fungal mycelial proliferation. According to our findings, fungal PAKs are interesting therapeutic targets for the development of new antifungal medicines.

Generating a Murine PTEN Null Cell Line to Discover the Key Role of p110β-PAK1 in Castration-Resistant Prostate Cancer Invasion

Although androgen deprivation treatment often effectively decreases prostate cancer, incurable metastatic castration-resistant prostate cancer (CRPC) eventually occurs. It is important to understand how CRPC metastasis progresses, which is not clearly defined. The loss of PTEN, a phosphatase to dephosphorylate phosphatidylinositol 3,4,5-trisphosphate in the PI3K pathway, occurs in up to 70% to 80% of CRPC. We generated a mouse androgen-independent prostate cancer cell line (PKO) from PTEN null and Hi-Myc transgenic mice in C57BL/6 background. We confirmed that this PKO cell line has an activated PI3K pathway and can metastasize into the femur and tibia of immunodeficient nude and immunocompetent C57BL/6 mice. In vitro, we found that androgen deprivation significantly enhanced PKO cell migration/invasion via the p110β isoform-depended PAK1-MAPK activation. Inhibition of the p110β-PAK1 axis significantly decreased prostate cancer cell migration/invasion. Of note, our analysis using clinical samples showed that PAK1 is more activated in CRPC than in advanced prostate cancer; high PAK1/phosphorylated-PAK1 levels are associated with decreased survival rates in patients with CRPC. All the information suggests that this cell line reflects the characteristics of CRPC cells and can be applied to dissect the mechanism of CRPC initiation and progression. This study also shows that PAK1 is a potential target for CRPC treatment.

IMPLICATIONS

This study uses a newly generated PTEN null prostate cancer cell line to define a critical functional role of p110β-PAK1 in CRPC migration/invasion. This study also shows that the p110β-PAK1 axis can potentially be a therapeutic target in CRPC metastasis.

STAT3-EphA7 axis contributes to the progression of esophageal squamous cell carcinoma

BACKGROUND

Our previous study has revealed that EphA7 was upregulated in patient-derived esophageal squamous cell carcinoma (ESCC) xenografts with hyper-activated STAT3, but its mechanism was still unclear.

MATERIALS AND METHODS

To assess the association between EphA7 and STAT3, western blotting, immunofluorescence, ChIP assay, and qRT-PCR were conducted. Truncated mutation and luciferase assay were performed to examine the promoter activity of EphA7. CCK-8 assay and colony formation were performed to assess the proliferation of ESCC. Cell-derived xenograft models were established to evaluate the effects of EphA7 on ESCC tumor growth. RNA-seq analyses were used to assess the effects of EphA7 on related signals.

RESULTS

In this study, EphA7 was found upregulated in ESCC cell lines with high STAT3 activation, and immunofluorescence also showed that EphA7 was co-localized with phospho-STAT3 in ESCC cells. Interestingly, suppressing STAT3 activation by the STAT3 inhibitor Stattic markedly inhibited the protein expression of EphA7 in ESCC cells, in contrast, activation of STAT3 by IL-6 obviously upregulated the protein expression of EphA7. Moreover, the transcription of EphA7 was also mediated by the activation of STAT3 in ESCC cells, and the -2000∼-1500 region was identified as the key promoter of EphA7. Our results also indicated that EphA7 enhanced the cell proliferation of ESCC, and silence of EphA7 significantly suppressed ESCC tumor growth. Moreover, EphA7 silence markedly abolished STAT3 activation-derived cell proliferation of ESCC. Additionally, RNA-seq analyses indicated that several tumor-related signaling pathways were significantly changed after EphA7 downregulation in ESCC cells.

CONCLUSION

Our results showed that the transcriptional expression of EphA7 was increased by activated STAT3, and the STAT3 signaling may act through EphA7 to promote the development of ESCC.

TonEBP expression is essential in the IL-1β-induced migration and invasion of human A549 lung cancer cells

Lung cancer has the highest mortality rate among all cancers, in part because it readily metastasizes. The tumor microenvironment, comprising blood vessels, fibroblasts, immune cells, and macrophages [including tumor-associated macrophages (TAMs)], is closely related to cancer cell growth, migration, and invasion. TAMs secrete several cytokines, including interleukin (IL)-1β, which participate in cancer migration and invasion. p21-activated kinase 1 (PAK1), an important signaling molecule, induces cell migration and invasion in several carcinomas. Tonicity-responsive enhancer-binding protein (TonEBP) is also known to participate in cancer cell growth, migration, and invasion. However, the mechanisms by which it increases lung cancer migration remain unclear. Therefore, in this study, we aimed to elucidate the mechanisms by which IL-1β and TonEBP affect lung cancer cell migration and invasion. We found that A549 cocultured-MΦ-secreted IL-1β induced A549 cell migration and invasion via the PAK1 pathway. TonEBP deficiency reduced A549 cell migration and invasion and increased responsiveness to IL-1β-induced migration and invasion. PAK1 phosphorylation, which was promoted by IL-1β, was reduced when TonEBP was depleted. These results suggest that TonEBP plays an important role in IL-1β induction and invasiveness of A549 cells via the PAK1 pathway. These findings could be valuable in identifying potential targets for lung cancer treatment.

NUAK1 promotes tumor metastasis through upregulating slug transcription in esophageal squamous cell carcinoma

BACKGROUND

Metastasis is still a major cause of poor pathological outcome and prognosis in esophageal squamous cell carcinoma (ESCC) patients. NUAK1 has been reported highly expressed in many human cancers and is associated with the poor prognosis of cancer patients. However, the role of NUAK1 and its underlying signaling mechanism in ESCC metastasis remain unclear.

METHODS

Expression of NUAK1 in ESCC was detected by real-time quantitative RT-PCR (qRT-PCR), Western blotting and immunohistochemical staining. MTT, colony formation, wound-healing and transwell assays were used to determine the role NUAK1 in vitro. Metastasis was evaluated by use of an experimental pulmonary metastasis model in BALB/c-nu/nu mice. The mechanisms were assessed by using coimmunoprecipitation, immunofluorescence and dual-luciferase reporter gene experiments.

RESULTS

NUAK1 was highly expressed in ESCC tissues compared with the adjacent normal esophageal epithelial tissues. Moreover, the elevated expression of NUAK1 positively correlated with tumor invasion depth, lymph node metastasis, pathological TNM stage, and poor survival in ESCC patients. Further experiments showed that NUAK1 overexpression did not change the cell viability and colony formation of ESCC cells, while remarkably promoted the migration and invasion in vitro and experimental pulmonary metastasis in vivo. Mechanistically, NUAK1 enhanced the transcription level of Slug, which enhanced the migratory and invasive capability of ESCC cells. Consistently, silencing Slug almost completely diminished the migration and invasion of NUAK1-overexpressing ESCC cells. Further studies demonstrated that NUAK1 upregulated the transcription activity of Slug through activating the JNK/c-Jun pathway.

CONCLUSION

These results demonstrated that NUAK1 promoted the metastasis of ESCC cells through activating JNK/c-Jun/Slug signaling, indicating NUAK1 is a promising therapeutic target for metastatic ESCC.

PLCD3 promotes malignant cell behaviors in esophageal squamous cell carcinoma via the PI3K/AKT/P21 signaling

BACKGROUND

Phospholipase C Delta 3 (PLCD3) is a member of phospholipase C(PLC) Protein and PLCD3 protein plays a prominent role in many cancers. However, little is known about the role of PLCD3 in esophageal squamous cell carcinoma (ESCC).

MATERIAL AND METHODS

We analyzed PLCD3 mRNA and protein expression in ESCC tissues and cell lines by immunohistochemistry, quantitative real-time PCR, and western blot. The correlation between PLCD3 expression and clinicopathological characteristics was also analyzed. CCK8, colony formation, wound-healing, and transwell assays were conducted to measure cell functional alternations. Flow cytometry was performed to assess the apoptosis rate and cell cycle caused by PLCD3 knockdown. Xenograft models in nude mice to clarify the role of PLCD3 in ESCC. Key proteins in the PI3K / AKT signaling pathway after treatment of ECA109 and KYSE150 cells with the AKT inhibitor MK2206 were analyzed by western blot.

RESULTS

PLCD3 was highly expressed in ESCC tissues and cell lines. PLCD3 expression levels correlated with pathologic stage and lymphatic metastasis. PLCD3 knockdown inhibited cell proliferation, migration, invasion, promoted apoptosis, and caused the cell cycle arrest in the G1 phase. PLCD3 overexpression promoted cell proliferation, migration, and invasion. In vivo experiments with xenografts demonstrated that PLCD3 promoted ESCC tumorigenesis. Finally, Overexpression of PLCD3 activated the PI3K / AKT / P21 signaling.

CONCLUSION

PLCD3 promotes malignant cell behaviors in esophageal squamous cell carcinoma via the PI3K/AKT/P21 signaling and could serve as a potential target for ESCC treatment.

Targeting P21-Activated Kinase-1 for Metastatic Prostate Cancer

Metastatic prostate cancer (mPCa) has limited therapeutic options and a high mortality rate. The p21-activated kinase (PAK) family of proteins is important in cell survival, proliferation, and motility in physiology, and pathologies such as infectious, inflammatory, vascular, and neurological diseases as well as cancers. Group-I PAKs (PAK1, PAK2, and PAK3) are involved in the regulation of actin dynamics and thus are integral for cell morphology, adhesion to the extracellular matrix, and cell motility. They also play prominent roles in cell survival and proliferation. These properties make group-I PAKs a potentially important target for cancer therapy. In contrast to normal prostate and prostatic epithelial cells, group-I PAKs are highly expressed in mPCA and PCa tissue. Importantly, the expression of group-I PAKs is proportional to the Gleason score of the patients. While several compounds have been identified that target group-I PAKs and these are active in cells and mice, and while some inhibitors have entered human trials, as of yet, none have been FDA-approved. Probable reasons for this lack of translation include issues related to selectivity, specificity, stability, and efficacy resulting in side effects and/or lack of efficacy. In the current review, we describe the pathophysiology and current treatment guidelines of PCa, present group-I PAKs as a potential druggable target to treat mPCa patients, and discuss the various ATP-competitive and allosteric inhibitors of PAKs. We also discuss the development and testing of a nanotechnology-based therapeutic formulation of group-I PAK inhibitors and its significant potential advantages as a novel, selective, stable, and efficacious mPCa therapeutic over other PCa therapeutics in the pipeline.

P-21 Activated Kinases in Liver Disorders

The p21 Activated Kinases (PAKs) are serine threonine kinases and play important roles in many biological processes, including cell growth, survival, cytoskeletal organization, migration, and morphology. Recently, PAKs have emerged in the process of liver disorders, including liver cancer, hepatic ischemia-reperfusion injury, hepatitis, and liver fibrosis, owing to their effects in multiple signaling pathways in various cell types. Activation of PAKs promotes liver cancer growth and metastasis and contributes to the resistance of liver cancer to radiotherapy and chemotherapy, leading to poor survival of patients. PAKs also play important roles in the development and progression of hepatitis and other pathological processes of the liver such as fibrosis and ischemia-reperfusion injury. In this review, we have summarized the currently available studies about the role of PAKs in liver disorders and the mechanisms involved, and further explored the potential therapeutic application of PAK inhibitors in liver disorders, with the aim to provide a comprehensive overview on current progress and perspectives of PAKs in liver disorders.

KISS-1, Mediated by Promoter Methylation, Suppresses Esophageal Squamous Cell Carcinoma Metastasis via MMP2/9/MAPK Axis

BACKGROUND AND AIMS

KISS-1 is an established tumor suppressor that inhibits metastases in various malignancies. However, little is known regarding its role in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to identify the possible mechanisms of KISS-1 in ESCC metastasis.

METHODS

The expression levels of KISS-1 mRNA and protein in ESCC samples and cell lines were analyzed by qRT-PCR, IHC, and western blotting. Bisulfite sequencing PCR (BSP) and methylation-specific PCR (MSP) were used to analyze the methylation pattern of KISS-1 promoter in ESCC cells with or without 5-Aza-dC treatment. The role of KISS-1 in the progression and metastasis of ESCC was analyzed through in vitro functional assays.

RESULTS

KISS-1 mRNA and protein were markedly downregulated in ESCC tissues and cell lines compared to the respective controls. Hypermethylation of KISS-1 promoter correlated to its lower expression levels in ESCC, and KISS-1 demethylation inhibited tumor progression. Ectopic KISS-1 overexpression inhibited tumor cell metastasis in vitro. In addition, KISS-1 overexpression downregulated the matrix metalloproteinase 2 and 9 (MMP2 and 9) and inhibited epithelial-mesenchymal transition (EMT). Finally, KISS-1 downregulated phosphorylated extracellular regulated protein kinase 1/2 (ERK1/2) and phosphorylated p38 mitogen-activated protein kinase (MAPK) without affecting their total expression levels in the ESCC cells. MAPK/ERK and p38 MAPK agonists reversed the suppressive effects of KISS-1.

CONCLUSIONS

The hypermethylation of KISS-1 promoter partly contributed to its downregulation in ESCC. KISS-1 inhibits the metastasis of ESCC cells by targeting the MMP2/9/ERK/p38 MAPK axis.

Metastasis prevention: targeting causes and roots

The spread of tumor cells from the primary focus, metastasis, is the main cause of cancer mortality. Therefore, anticancer therapy should be focused on the prevention of metastatic disease. Key targets can be conditions in the primary tumor that are favorable for the appearance of metastatic cells and the first steps of the metastatic cascade. Here, we discuss different approaches for targeting metastasis causes (hypoxia, metabolism changes, and tumor microenvironment) and roots (angiogenesis, epithelial-mesenchymal transition, migration, and invasion). Also, we emphasize the challenges of the existing approaches for metastasis prevention and suggest opportunities to overcome them. In conclusion, we highlight the importance of clinical evaluation of the agents showing antimetastatic effects in vivo, especially in patients with early-stage cancers, the identification of metastatic seeds, and the development of therapeutics for their eradication.

Transcriptional inhibition by CDK7/9 inhibitor SNS-032 suppresses tumor growth and metastasis in esophageal squamous cell carcinoma

Metastasis is one of most lethal causes that confer a poor prognosis of patients with esophageal squamous cell carcinoma (ESCC), whereas there is no available target drug for metastatic ESCC currently. In this study, we aimed to determine whether the transcriptional inhibition by CDK7/9 inhibitor SNS-032 is activity against ESCC. MTT and soft agar assays were performed to examine the influence of SNS-032 on ESCC growth in vitro. Tumor xenograft in nude mice was used to assess the antitumor activity of SNS-032 in vivo. The roles of SNS-032 in ESCC metastasis were conducted by wound healing and transwell assays in vitro, and by a lung and a popliteal lymph node metastasis model in vivo. The results showed that CDK7 and CDK9 were highly expressed in ESCC cells; SNS-032 effectively inhibited cellular viability, abrogated anchorage-independent growth, and potentiated the sensitivity to cisplatin in ESCC cells in vitro and in vivo. In addition, SNS-032 induced a mitochondrial-dependent apoptosis of ESCC cells by reducing Mcl-1 transcription. SNS-032 also potently abrogated the abilities of ESCC cell migration and invasion through transcriptional downregulation of MMP-1. Importantly, SNS-032 remarkably inhibited the growth of ESCC xenograft, increased the overall survival, as well as diminished the lung and lymph node metastasis in nude mice. Taken together, our findings highlight that the CDK7/9 inhibitor SNS-032 is a promising therapeutic agent, and warrants a clinical trial for its efficacy in ESCC patients, even those with metastasis.

TM7SF2 regulates cell proliferation and apoptosis by activation of C-Raf/ERK pathway in cervical cancer

Transmembrane 7 superfamily member 2 (TM7SF2) coding an enzyme involved in cholesterol metabolism has been found to be differentially expressed in kinds of tissues. Nevertheless, the role of TM7SF2 in the regulation of growth and progression among various cancers is unclear. In this study, the immunohistochemistry (IHC) assay, real-time RT-PCR and western blotting analysis were used to determine the TM7SF2 expression in cervical cancer tissues. Next, we used multiple methods to determine the ability of cell proliferation, migration, invasion, apoptosis, and cell cycle in cervical cancer cells after TM7SF2 modulation, such as CCK8 assay, colony formation assay, Transwell assay, wound healing assay, and flow cytometry. Our results revealed that upregulation of TM7SF2 facilitated cell proliferation and metastasis, suppressed cell apoptosis and prevented G0/G1 phase arrests in C33A and SiHa cells. Consistently, the opposite effects were observed after TM7SF2 knockout in cervical cancer cells. Further, we found that TM7SF2 participated in promoting tumorigenesis and progression via activation of C-Raf/ERK pathway in cervical cancer, which can be partly reversed by Raf inhibitor LY3009120. Moreover, TM7SF2 overexpression contributed to enhancement of xenograft tumor growth in vivo. Our findings indicated that TM7SF2 plays a vital role in tumor promotion by involving in C-Raf/ERK activation. Therefore, TM7SF2 could serve as a therapeutic target in future cervical cancer treatment.

Anticancer effects of 6-shogaol via the AKT signaling pathway in oral squamous cell carcinoma

Objective

Oral squamous cell carcinoma (OSCC) is one of the common type of cancer that leads to death; and is becoming a global concern. Due to the lack of efficient chemotherapeutic agents for patients with oral cancer, the prognosis remains poor. 6-shogaol, a bioactive compound of ginger, has a broad spectrum of bioactivities and has been widely used to relieve many diseases. However, its effects on human oral cancer have not yet been fully evaluated. In our study, we investigated the anticancer effects of 6-shogaol on the proliferation, migration, invasion, apoptosis, and underlying mechanisms within human OSCC cell lines.

Methodology

We investigated the effect of 6-shogaol on the growth of OSCC cells by cell viability and soft agar colony formation assay. Migration and invasion assays were conducted to confirm the effect 6-shogaol on OSCC cell metastasis. Apoptosis was detected by flow cytometry and the underlying mechanism on the antigrowth effect of 6-shogaol in OSCC cells was assessed using western blotting.

Results

In our results, 6-shogaol not only suppressed proliferation and anchorage-independent cell growth in OSCC cells, but also induced apoptosis by regulating the apoptosis-associated factors such as p53, Bax, Bcl-2, and cleaved caspase-3. Migration and invasion of OSCC cells were inhibited following the regulation of E-cadherin and N-cadherin by 6-shogaol. Additionally, 6-shogaol treatment significantly inhibited the PI3K/AKT signaling pathway.

Conclusion

Therefore, our results may provide critical evidence that 6-shogaol can be a potential new therapeutic candidate for oral cancer.

Comprehensive Analysis and Identification of Key Driver Genes for Distinguishing Between Esophageal Adenocarcinoma and Squamous Cell Carcinoma

Background: Esophageal cancer (EC) is one of the deadliest cancers in the world. However, the mechanism that drives the evolution of EC is still unclear. On this basis, we identified the key genes and molecular pathways that may be related to the progression of esophageal adenocarcinoma and squamous cell carcinoma to find potential markers or therapeutic targets. Methods: GSE26886 were obtained from Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) among normal samples, EA, and squamous cell carcinoma were determined using R software. Then, potential functions of DEGs were determined using the Database for Annotation, Visualization and Integrated Discovery (DAVID). The STRING software was used to identify the most important modules in the protein-protein interaction (PPI) network. The expression levels of hub genes were confirmed using UALCAN database. Kaplan-Meier plotters were used to confirm the correlation between hub genes and outcomes in EC. Results: In this study, we identified 1,098 genes induced in esophageal adenocarcinoma (EA) and esophageal squamous cell carcinoma (ESCC), and 669 genes were reduced in EA and ESCC, suggesting that these genes may play an important role in the occurrence and development of EC tumors. Bioinformatics analysis showed that these genes were involved in cell cycle regulation and p53 and phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. In addition, we identified 147 induced genes and 130 reduced genes differentially expressed in EA and ESCC. The expression of ESCC in the EA group was different from that in the control group. By PPI network analysis, we identified 10 hub genes, including GNAQ, RGS5, MAPK1, ATP1B1, HADHA, HSDL2, SLC25A20, ACOX1, SCP2, and NLN. TCGA validation showed that these genes were present in the dysfunctional samples between EC and normal samples and between EA and ESCC. Kaplan-Meier analysis showed that MAPK1, ACOX1, SCP2, and NLN were associated with overall survival in patients with ESCC and EA. Conclusions: In this study, we identified a series of DEGs between EC and normal samples and between EA and ESCC samples. We also identified 10 key genes involved in the EC process. We believe that this study may provide a new biomarker for the prognosis of EA and ESCC.

Design, synthesis and biological evaluation of novel tetrahydrothieno [2,3-c]pyridine substitued benzoyl thiourea derivatives as PAK1 inhibitors in triple negative breast cancer

The overexpression of P21-activated kinase 1 (PAK1) is associated with poor prognosis in several cancers, which has emerged as a promising drug targets. Based on high-throughput virtual screening strategy, tetrahydrothieno [2,3-c]pyridine scaffold was identified as an initial lead for targeting PAK1. Herein we reported our structure-based optimisation strategy to discover a potent PAK1 inhibitor (7j) which displayed potent PAK1 inhibition and antiproliferatory activity in MDA-MB-231 cells. 7j induced obviously G2/M cell cycle arrest via PAK1-cdc25c-cdc2 pathway, and also inhibited MAPK-ERK and MAPK-JNK cascade to induce MDA-MB-231 cell death. Together, these results provided a novel chemical scaffold as PAK1 inhibitor for breast cancer treatment.

Targeting AKT with costunolide suppresses the growth of colorectal cancer cells and induces apoptosis in vitro and in vivo

BACKGROUND

Colorectal cancer (CRC) is a clinically challenging malignant tumor worldwide. As a natural product and sesquiterpene lactone, Costunolide (CTD) has been reported to possess anticancer activities. However, the regulation mechanism and precise target of this substance remain undiscovered in CRC. In this study, we found that CTD inhibited CRC cell proliferation in vitro and in vivo by targeting AKT.

METHODS

Effects of CTD on colon cancer cell growth in vitro were evaluated in cell proliferation assays, migration and invasion, propidium iodide, and annexin V-staining analyses. Targets of CTD were identified utilizing phosphoprotein-specific antibody array; Costunolide-sepharose conjugated bead pull-down analysis and knockdown techniques. We investigated the underlying mechanisms of CTD by ubiquitination, immunofluorescence staining, and western blot assays. Cell-derived tumour xenografts (CDX) in nude mice and immunohistochemistry were used to assess anti-tumour effects of CTD in vivo.

RESULTS

CTD suppressed the proliferation, anchorage-independent colony growth and epithelial-mesenchymal transformation (EMT) of CRC cells including HCT-15, HCT-116 and DLD1. Besides, the CTD also triggered cell apoptosis and cell cycle arrest at the G2/M phase. The CTD activates and induces p53 stability by inhibiting MDM2 ubiquitination via the suppression of AKT's phosphorylation in vitro. The CTD suppresses cell growth in a p53-independent fashion manner; p53 activation may contribute to the anticancer activity of CTD via target AKT. Finally, the CTD decreased the volume of CDX tumors without of the body weight loss and reduced the expression of AKT-MDM2-p53 signaling pathway in xenograft tumors.

CONCLUSIONS

Our project has uncovered the mechanism underlying the biological activity of CTD in colon cancer and confirmed the AKT is a directly target of CTD. All of which These results revealed that CTD might be a new AKT inhibitor in colon cancer treatment, and CTD is worthy of further exploration in preclinical and clinical trials.

Upregulation of PEDF Predicts a Poor Prognosis and Promotes Esophageal Squamous Cell Carcinoma Progression by Modulating the MAPK/ERK Signaling Pathway

Invasion and metastasis represent the primary causes of therapeutic failure in patients diagnosed with esophageal squamous cell carcinoma (ESCC). The lack of effective treatment strategies for metastatic ESCC is the major cause of the low survival rate. Therefore, it is crucial to understand the molecular mechanisms underlying ESCC metastasis and identify potential biomarkers for targeted therapy. Herein, we reported that PEDF is significantly correlated with tumor cell invasion and metastasis in ESCC. The high expression of PEDF is an independent unfavorable prognostic factor for ESCC patients’ overall survival (OS). We successfully developed and verified a nomogram to predict the preoperative OS of ESCC patients, and the actual and nomogram-predicted 1-, 3-, and 5-year survival rates had good consistency. The receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) values for 1-, 3- and 5- survival were 0.764, 0.871, and 0.91, respectively. Overexpression of PEDF significantly promoted the migration and invasion of ESCC cells in vitro, while silencing PEDF yielded the opposite effects. Elevated levels of PEDF altered the expression of proteins involved in epithelial–mesenchymal transition (EMT), as indicated by the upregulation of N-cadherin and the downregulation of α-catenin and E-cadherin in ESCC cells. Mechanistically, PEDF promoted tumor cell motility and EMT by activating the MAPK/ERK signaling pathway. In conclusion, our results reveal that PEDF is involved in ESCC metastasis and could act as a prognostic factor for ESCC. Our research provides a fresh perspective into the mechanism of ESCC metastasis.

PAK1 as a Potential Therapeutic Target in Male Smokers with EGFR-Mutant Non-Small Cell Lung Cancer

P21-activated kinases (PAKs) are serine/threonine protein kinases that contribute to several cellular processes. Here, we aimed to determine the prognostic value of PAK1 and its correlation with the clinicopathological characteristics and five-year survival rates in patients with non-small cell lung cancer (NSCLC). We evaluated PAK1 mRNA and protein expression in NSCLC cells and resected tumor specimens, as well as in healthy human bronchial epithelial cells and adjacent healthy lung tissues, respectively, for effective comparison. Immunohistochemical tissue microarray analysis of 201 NSCLC specimens showed the correlation of PAK1 expression with clinicopathological characteristics. The mRNA and protein expression of PAK1 were 2.9- and 4.3-fold higher in six of seven NSCLC cell types and human tumors (both, p < 0.001) than in healthy human bronchial epithelial BEAS-2B cells and adjacent healthy lung tissues, respectively. Decreased survival was significantly associated with PAK1 overexpression in the entire cohort (χ² = 8.48, p = 0.0036), men (χ² = 17.1, p < 0.0001), and current and former smokers (χ² = 19.2, p < 0.0001). Notably, epidermal growth factor receptor (EGFR) mutation-positive lung cancer patients with high PAK1 expression showed higher mortality rates than those with low PAK1 expression (91.3% vs. 62.5%, p = 0.02). Therefore, PAK1 overexpression could serve as a molecular target for the treatment of EGFR mutation-positive lung cancer, especially among male patients and current/former smokers.

LEF1/Id3/HRAS axis promotes the tumorigenesis and progression of esophageal squamous cell carcinoma

Our previous study demonstrated that lymphoid enhancer-binding factor 1 (LEF1) could promote the progression of esophageal squamous cell carcinoma (ESCC). However, the regulatory mechanism of LEF1 was not clear thoroughly. Herein, we continued to explore the downstream mechanism of LEF1 in ESCC. In this study, we applied western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry, RNA-Seq analysis, a luciferase reporter assay, chromatin immunoprecipitation (ChIP), bioinformatics analysis, and a series of functional assays in vitro and in vivo. The results demonstrated that LEF1 regulated directly the expression of Id3. Id3 was highly expressed in ESCC tissues and correlated with histologic differentiation (p=0.011), pT stage (p<0.01) and AJCC stage (p<0.01) in ESCC patients. Moreover, Id3 could serve as a prognostic factor of ESCC. By various functional experiments, overexpression of Id3 promoted the proliferation, migration, invasion, EMT, and tumorgenicity. Mechanistically, Id3 could regulate ERK/MAPK signaling pathway via activating HRAS to perform its biological function. Furthermore, activating ERK/MAPK signaling pathway promoted the expression of Id3 gene in turn, indicating that a positive regulatory loop between Id3 and ERK/MAPK pathway may exist in ESCC. In summary, LEF1/Id3/HRAS axis could promote the tumorigenesis and progression of ESCC via activating ERK/MAPK signaling pathway. Targeting this cascade may provide a valid antitumor strategy to delay ESCC progress.

Small Ones to Fight a Big Problem-Intervention of Cancer Metastasis by Small Molecules

Metastasis represents the most lethal attribute of cancer and critically limits successful therapies in many tumor entities. The clinical need is defined by the fact that all cancer patients, who have or who will develop distant metastasis, will experience shorter survival. Thus, the ultimate goal in cancer therapy is the restriction of solid cancer metastasis by novel molecularly targeted small molecule based therapies. Biomarkers identifying cancer patients at high risk for metastasis and simultaneously acting as key drivers for metastasis are extremely desired. Clinical interventions targeting these key molecules will result in high efficiency in metastasis intervention. In result of this, personalized tailored interventions for restriction and prevention of cancer progression and metastasis will improve patient survival. This review defines crucial biological steps of the metastatic cascade, such as cell dissemination, migration and invasion as well as the action of metastasis suppressors. Targeting these biological steps with tailored therapeutic strategies of intervention or even prevention of metastasis using a wide range of small molecules will be discussed.

Suppression of cathepsin a inhibits growth, migration, and invasion by inhibiting the p38 MAPK signaling pathway in prostate cancer

Prostate cancer has the highest incidence among men in advanced countries, as well as a high mortality rate. Despite the efforts of numerous researchers to identify a gene-based therapeutic target as an effective treatment of prostate cancer, there is still a need for further research. The cathepsin gene family is known to have a close correlation with various cancer types and is highly expressed across these cancer types. This study aimed at investigating the correlation between the cathepsin A (CTSA) gene and prostate cancer. Our findings indicated a significantly elevated level of CTSA gene expression in the tissues of patients with prostate cancer when compared with normal prostate tissues. Furthermore, the knockdown of the CTSA gene in the representative prostate cancer cell lines PC3 and DU145 led to reduced proliferation and a marked reduction in anchorage-independent colony formation, which was shown to be caused by cell cycle arrest in the S phase. In addition, CTSA gene-knockdown prostate cancer cell lines showed a substantial decrease in migration and invasion, as well as a decrease in the marker genes that promote epithelial mesenchymal transition (EMT). Such phenotypic changes in prostate cancer cell lines through CTSA gene suppression were found to be mainly caused by reduced p38 MAPK protein phosphorylation; i.e. the inactivation of the p38 MAPK cell signaling pathway. Tumorigenesis was also found to be inhibited in CTSA gene-knockdown prostate cancer cell lines when a xenograft assay was carried out using Balb/c nude mice, and the p38 MAPK phosphorylation was inhibited in tumor tissues. Thus, the CTSA gene is presumed to play a key role in human prostate cancer tissues through high-level expression, and the suppression of the CTSA gene leads to the inhibition of prostate cancer cell proliferation, colony formation, and metastasis. The mechanism, by which these effects occur, was demonstrated to be the inactivation of the p38 MAPK signaling pathway.

Ivermectin suppresses tumour growth and metastasis through degradation of PAK1 in oesophageal squamous cell carcinoma

Oesophageal squamous cell carcinoma (ESCC), the most common form of oesophageal malignancies in the Asia‐Pacific region, remains a major clinical challenge. In this study, we found that ivermectin, an effective antiparasitic drug that has been approved for patients to orally treat onchocerciasis for over 30 years, displayed potent antitumour activity against ESCC cells in vitro and in nude mice. We demonstrated that ivermectin significantly inhibited cell viability and colony formation, and induced apoptosis through a mitochondrial‐dependent manner in ESCC cells. Ivermectin also abrogated ESCC cell migration, invasion, as well as the protein levels of MMP‐2 and MMP‐9. Mechanistically, ivermectin strongly inhibited the expression of PAK1; by further gain‐ and loss‐of‐function experiments, we confirmed that PAK1 played a crucial role in ivermectin‐mediated inhibitory effects on ESCC cells. In addition, the data indicated that ivermectin promoted PAK1 degradation through the proteasome‐dependent pathway. Additionally, ivermectin synergized with chemotherapeutic drugs including cisplatin and 5‐fluorouracil to induce apoptosis of ESCC cells. Interestingly, the in vivo experiments also confirmed that ivermectin effectively suppressed tumour growth and lung metastasis of ESCC. Collectively, these results indicate that ivermectin exerts a potent antitumour activity against ESCC and is a promising therapeutic candidate drug for ESCC patients, even those carrying metastasis.

Understanding and Modeling Metastasis Biology to Improve Therapeutic Strategies for Combating Osteosarcoma Progression

Osteosarcoma is a malignant primary tumor of bone, arising from transformed progenitor cells with osteoblastic differentiation and osteoid production. While categorized as a rare tumor, most patients diagnosed with osteosarcoma are adolescents in their second decade of life and underscores the potential for life changing consequences in this vulnerable population. In the setting of localized disease, conventional treatment for osteosarcoma affords a cure rate approaching 70%; however, survival for patients suffering from metastatic disease remain disappointing with only 20% of individuals being alive past 5 years post-diagnosis. In patients with incurable disease, pulmonary metastases remain the leading cause for osteosarcoma-associated mortality; yet identifying new strategies for combating metastatic progression remains at a scientific and clinical impasse, with no significant advancements for the past four decades. While there is resonating clinical urgency for newer and more effective treatment options for managing osteosarcoma metastases, the discovery of druggable targets and development of innovative therapies for inhibiting metastatic progression will require a deeper and more detailed understanding of osteosarcoma metastasis biology. Toward the goal of illuminating the processes involved in cancer metastasis, a convergent science approach inclusive of diverse disciplines spanning the biology and physical science domains can offer novel and synergistic perspectives, inventive, and sophisticated model systems, and disruptive experimental approaches that can accelerate the discovery and characterization of key processes operative during metastatic progression. Through the lens of trans-disciplinary research, the field of comparative oncology is uniquely positioned to advance new discoveries in metastasis biology toward impactful clinical translation through the inclusion of pet dogs diagnosed with metastatic osteosarcoma. Given the spontaneous course of osteosarcoma development in the context of real-time tumor microenvironmental cues and immune mechanisms, pet dogs are distinctively valuable in translational modeling given their faithful recapitulation of metastatic disease progression as occurs in humans. Pet dogs can be leveraged for the exploration of novel therapies that exploit tumor cell vulnerabilities, perturb local microenvironmental cues, and amplify immunologic recognition. In this capacity, pet dogs can serve as valuable corroborative models for realizing the science and best clinical practices necessary for understanding and combating osteosarcoma metastases.

Maternal Embryonic Leucine Zipper Kinase Promotes Tumor Growth and Metastasis via Stimulating FOXM1 Signaling in Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common gastrointestinal malignancy and is one of the most important cause of cancer related mortalities in the world. However, there is no clinically effective targeted therapeutic drugs for ESCC due to lack of valuable molecular therapeutic targets. In the present study, we investigated the biological function and molecular mechanisms of maternal embryonic leucine zipper kinase (MELK) in ESCC. The expression of MELK mRNA and protein was determined in cell lines and clinical samples of ESCC. MTT, focus formation and soft agar assays were carried out to measure cell proliferation and colony formation. Wound healing and transwell assays were used to assess the capacity of tumor cell migration and invasion. Nude mice models of subcutaneous tumor growth and lung metastasis were performed to examine the function of MELK in tumorigenecity and metastasis of ESCC cells. High expression of MELK was observed in ESCC cell line and human samples, especially in the metastatic tumor tissues. Moreover, overexpression of MELK promoted cell proliferation, colony formation, migration and invasion, and increased the expression and enzyme activity of MMP-2 and MMP-9 in ESCC cells. More importantly, enhanced expression of MELK greatly accelerated tumor growth and lung metastasis of ESCC cells in vivo. In contrast, knockdown of MELK by lentiviral shRNA resulted in an opposite effect both in vitro and in animal models. Mechanistically, MELK facilitated the phosphorylation of FOXM1, leading to activation of its downstream targets (PLK1, Cyclin B1, and Aurora B), and thereby promoted tumorigenesis and metastasis of ESCC cells. In conclusion, MELK enhances tumorigenesis, migration, invasion and metastasis of ESCC cells via activation of FOXM1 signaling pathway, suggesting MELK is a potential therapeutic target for ESCC patients, even those in an advanced stage.

Three new cyclopiane-type diterpenes from a deep-sea derived fungus Penicillium sp. YPGA11 and their effects against human esophageal carcinoma cells

Cyclopianes, featuring a highly rigid 6/5/5/5-fused tetracyclic framework, are structurally unique and biologically significant and belong to a rarely reported diterpenoid family. Chemical investigation of an EtOAc extract of a deep-sea-derived Penicillium sp. led to the isolation of three new cyclopiane diterpenes, namely, conidiogenols C-D (1-2) and conidiogenone L (3). The structures were determined by extensive analyses of the spectroscopic data in association with ECD calculations and chemical conversion for configurational assignments. Compound 1 represents the second example of cyclopianes bearing a hydroxyl group at C-13. Compound 2, the third example of conidiogenols, possesses a distinct α-oriented 1-hydroxy group relative to other analogues. The bioassay study demonstrated that compounds 2 and 4-6 exhibited moderate inhibitory effects against five esophageal cancer cell lines with IC₅₀ values ranging from 25 to 55 μM. The cytotoxicities of all compounds toward esophageal cancer cell lines were evaluated for the first time.