Calreticulin promotes EGF-induced EMT in pancreatic cancer cells via Integrin/EGFR-ERK/MAPK signaling pathway

ENKUR acts as a tumor suppressor in lung adenocarcinoma cells through PI3K/Akt and MAPK/ERK signaling pathways

Lung adenocarcinoma (LAD) is the most common type of lung cancer with a high possibility of tumor relapse and metastasis. ENKUR (Enkurin) was originally identified as a potential regulator or effector of TRPC channels that directly binds to several TRPC proteins and the p85 subunit of PI3K. However, the role of ENKUR in cancer development has remained unclear. In this study we analyzed the expression profile of ENKUR mRNA in clinical LAD samples and examined ENKUR mRNA expression and ENKUR protein level in LAD cells. Significant down-regulated ENKUR expression was observed in clinical tumor tissues of LAD as well as in human LAD cells. To evaluate the effects of aberrant ENKUR expression on cellular biology of LAD cells in vitro and tumor growth in vivo, ENKUR-overexpressed and -silenced LAD cell lines were constructed using lentiviral vectors. Our results showed that overexpression of ENKUR in LAD cells inhibited cell proliferation, migration and invasion, while silencing of ENKUR led to the opposite effects. Silencing of ENKUR in LAD cells also promoted tumorigenesis in nude mice model and caused epithelial to mesenchymal transition (EMT). Furthermore, using western blot and co-immunoprecipitation analyses, we demonstrated that ENKUR interacts with PI3K directly and is possibly involved in the PI3K/Akt and MAPK/ERK signaling pathways.

Ddx4+ Oogonial Stem Cells in Postmenopausal Women's Ovaries: A Controversial, Undefined Role

Recent studies support the existence of oogonial stem cells (OSCs) in the ovarian cortex of different mammals, including women.These cells are characterized by small size, membrane expression of DEAD(Asp-Glu-Ala-Asp)-box polypeptide-4 (Ddx4), and stemness properties (such as self-renewal and clonal expansion) as well as the ability to differentiate in vitro into oocyte-like cells. However, the discovery of OSCs contrasts with the popular theory that there is a numerically defined oocyte pool for female fertility which undergoes exhaustion with menopause. Indeed, in the ovarian cortex of postmenopausal women OSCs have been detected that possess both viability and capability to differentiate into oocytes, which is similar to those observed in younger patients. The pathophysiological role of this cell population in aged women is still debated since OSCs, under appropriate stimuli, differentiate into somatic cells, and the occurrence of Ddx4⁺ cells in ovarian tumor samples also suggests their potential involvement in carcinogenesis. Although further investigation into these observations is needed to clarify OSC function in ovary physiology, clinical investigators and researchers studying female infertility are presently focusing on OSCs as a novel opportunity to restore ovarian reserve in both young women undergoing early ovarian failure and cancer survivors experiencing iatrogenic menopause.

Synergistic Effect of Novel EGFR Inhibitor AZD8931 and p38α siRNA in Lung Adenocarcinoma Cancer Cells

Background:

Lung cancer is the leading cause of cancer-related death with less than 5-year survival rate for both men and women worldwide. EGFR and MAPK signaling pathways have a critical role in proliferation and progression of various cancers, including lung cancer. P38 map kinase plays different role in various tissue hence showing a tissue-dependent behavior. It acts as an oncogene in some tissues while plays as tumor suppressor in some other tissues. The aim of this study was to investigate the combined effect of P38 αspecific siRNA and EGFR inhibitor on apoptosis and proliferation of A549 lung cancer cell line.

Objective:

This article is dedicated to the synergistic effect of novel EGFR inhibitor AZD8931 and P38 α siRNA in lung adenocarcinoma cancer cells proliferation and apoptosis.

Methods and Materials:

The A549 lung cancer cells were treated with P38 α- siRNA and EGFR inhibitor alone or in combination. The cytotoxic effects of P38 α- siRNA and EGFR inhibitor were determined using MTT assay. Relative P38 α and EGFR mRNA levels were measured by QRT-PCR. Induction of apoptosis were measured by FACS analysis.

Results:

The expression of mRNA related to P38 α, EGFR, and Her2 genes was reduced to 23.4%, 52.4%, and 75, respectively, after treatment of their inhibitors. Also, MTT assay showed that the cell viability after treatment with p38 α SiRNA, EGFR inhibitor and their combination was reduced to 51.02%, 48.9%, and 25.11%, respectively. FACS results indicated that p38 α siRNA, EGFR inhibitor and their combination, reduced the population of live cells to 49.5%, 32.2% and 14.3% in comparison to the population of untreated control cells (99.5%).

Conclusion:

The results of this study indicated that p38 α and EGFR might play an important role in the development and growth of lung cancer and might be a potential therapeutic target for the treatment of lung cancer.

Crosstalk between autophagy and epithelial-mesenchymal transition and its application in cancer therapy

Autophagy is a highly conserved catabolic process that mediates degradation of pernicious or dysfunctional cellular components, such as invasive pathogens, senescent proteins, and organelles. It can promote or suppress tumor development, so it is a “double-edged sword” in tumors that depends on the cell and tissue types and the stages of tumor. The epithelial-mesenchymal transition (EMT) is a complex biological trans-differentiation process that allows epithelial cells to transiently obtain mesenchymal features, including motility and metastatic potential. EMT is considered as an important contributor to the invasion and metastasis of cancers. Thus, clarifying the crosstalk between autophagy and EMT will provide novel targets for cancer therapy. It was reported that EMT-related signal pathways have an impact on autophagy; conversely, autophagy activation can suppress or strengthen EMT by regulating various signaling pathways. On one hand, autophagy activation provides energy and basic nutrients for EMT during metastatic spreading, which assists cells to survive in stressful environmental and intracellular conditions. On the other hand, autophagy, acting as a cancer-suppressive function, is inclined to hinder metastasis by selectively down-regulating critical transcription factors of EMT in the early phases. Therefore, the inhibition of EMT by autophagy inhibitors or activators might be a novel strategy that provides thought and enlightenment for the treatment of cancer. In this article, we discuss in detail the role of autophagy and EMT in the development of cancers, the regulatory mechanisms between autophagy and EMT, the effects of autophagy inhibition or activation on EMT, and the potential applications in anticancer therapy.

ERK is a Pivotal Player of Chemo-Immune-Resistance in Cancer

The extracellular signal-related kinases (ERKs) act as pleiotropic molecules in tumors, where they activate pro-survival pathways leading to cell proliferation and migration, as well as modulate apoptosis, differentiation, and senescence. Given its central role as sensor of extracellular signals, ERK transduction system is widely exploited by cancer cells subjected to environmental stresses, such as chemotherapy and anti-tumor activity of the host immune system. Aggressive tumors have a tremendous ability to adapt and survive in stressing and unfavorable conditions. The simultaneous resistance to chemotherapy and immune system responses is common, and ERK signaling plays a key role in both types of resistance. In this review, we dissect the main ERK-dependent mechanisms and feedback circuitries that simultaneously determine chemoresistance and immune-resistance/immune-escape in cancer cells. We discuss the pros and cons of targeting ERK signaling to induce chemo-immune-sensitization in refractory tumors.

Ectopic expression of miR-944 impairs colorectal cancer cell proliferation and invasion by targeting GATA binding protein 6

miR-944 is a microRNA that has been reported to play different important roles in the progression of cancer. Colorectal cancer (CRC) is a common cancer worldwide. A recent study has confirmed that miR-944 plays a tumour suppressive role in CRC. However, biological functions and the mechanism of miR-944 in CRC are poorly understood. Real-time reverse transcription polymerase chain reaction of 100 CRC tissues showed that miR-944 expression is frequently downregulated and is negatively associated with the T is the primary tumor, N is the lymph node, and M is the distant metastasis (TNM) stage (P = 0.009), depth of invasion (P = 0.001), and lymph node status (P = 0.002). Overexpression of mir-944 significantly impaired the functions of proliferation, migration and invasion in CRC cells, while these functions increased in knockdown experiments. GATA binding protein 6 (GATA6) knockdown can reverse the CRC cells functions induced by miR-944 inhibitor. Mechanistically, a Dual-Luciferase Reporter Assay showed that miR-944 is structurally combined with GATA6 and interacts with downstream proteins (CRT and p-AKT) in CRC cells. In conclusion, these findings indicated that miR-944 may be a tumour suppressor and could likely be used as a prognostic predictor and novel therapeutic target for CRC.

MiR-9 promotes synovial sarcoma cell migration and invasion by directly targeting CDH1

BACKGROUND

Invasion and metastasis of synovial sarcoma is the leading cause of death in patients. Epithelial mesenchymal transition (EMT) accelerates tumor cell invasion and metastasis. MiR-9 promotes tumor metastasis by inducing EMT. However, the role of miR-9 in synovial sarcoma is still not clear.

METHODS

Overexpression or knockdown of miR-9 in human synovial sarcoma (HSS) cell lines was carried out by miR-9 mimics or miR-9 inhibitors transfection. Cell proliferation, apoptosis, migration and invasion were detected using MTS and colony formation assays, flow cytometry, wound healing and transwell assays, respectively. Luciferase reporter assay was applied to study the interaction between miR-9 and CDH1. Nude mice xenograft model was established, and immunohistochemistry staining assessed Ki-67 level. The related mRNA and protein expression levels were evaluated by qRT-PCR and Western blotting.

RESULTS

The bioinformatics analyses and luciferase reporter assay showed that miR-9 can target CDH1 3'-UTR. Moreover, miR-9 could induce EMT of HSS cells via targeting CDH1. The negative regulation of miR-9 on CDH1 expression was also confirmed in a mouse xenograft model of synovial sarcoma. Furthermore, miR-9 was observed to induce HSS cell proliferation, migration and invasion and inhibit apoptosis. MAPK/ERK and Wnt/β-catenin signal pathways were activated by the miR-9 overexpression in HSS cells, and then further enhancing tumorigenesis of HSS, which was further confirmed in the mouse model.

CONCLUSION

MiR-9 induces EMT by targeting CDH1, and activates MAPK/ERK and Wnt/β-catenin signal pathways, thus promoting HSS tumorigenesis.

TRPM7 promotes the epithelial-mesenchymal transition in ovarian cancer through the calcium-related PI3K / AKT oncogenic signaling

BACKGROUND

The epithelial-mesenchymal transition (EMT) is crucial for metastasis and positively regulated by calcium-related signaling. The melastatin-related transient receptor potential 7 (TRPM7) regulates a non-selective cation channel and promotes cancer metastasis. However, the mechanisms underlying the action of TRPM7 in ovarian cancer are unclear.

METHODS

The expression of TRPM7 and EMT markers (Vimentin, N-cadherin, Twist and E-cadherin) in ovarian cancer samples was detected. TRPM7was knockdown by shRNA in Ovarian cancer cell lines to examine calcium [Ca2+]i, EMT markers and PI3K/AKT markers. Various cellular assays, such as invasion and migration, were performed in vitro, and further confirmed in vivo.

RESULTS

TRPM7 expression is negatively correlated with E-cadherin, but positively with N-cadherin, Vimentin and Twist expression in ovarian cancer samples. TRPM7 depletion inhibited the migration and invasion in SKOV3 and OVCAR3 cells. In addition, TRPM7 silencing decreased the lung metastasis of SKOV3 tumors and prolonged the survival of tumor-bearing mice. Similar to that of TRPM7 silencing, treatment with MK886, a potent 5-lipoxygenase inhibitor to reduce TRPM7 expression, and/or BAPTA-AM, an intracellular calcium chelator, significantly mitigated the Epidermal growth factor (EGF) or Insulin-like growth factors (IGF)-stimulated migration, invasion, and the EMT in ovarian cancer cells by decreasing the levels of intracellular calcium [Ca2+]i. Furthermore, treatment with LY2904002, a PI3K inhibitor, also inhibited the migration, invasion, and treatment with both LY2904002 and BAPTA-AM further enhanced their inhibition in ovarian cancer cells. Moreover, treatment with BAPTA-AM mitigated the IGF-stimulated migration, invasion, particularly in TRPM7-silenced ovarian cancer cells. Finally, TRPM7 silencing attenuated the PI3K/AKT activation, which was enhanced by BAPTA-AM, MK886 or LY2904002 treatment in ovarian cancer cells.

CONCLUSIONS

TRPM7 silencing inhibited the EMT and metastasis of ovarian cancer by attenuating the calcium-related PI3k/AKT activation. Our findings suggest that TRPM7 may be a therapeutic target for intervention of ovarian cancer.

CD110 promotes pancreatic cancer progression and its expression is correlated with poor prognosis

PURPOSE

This study aimed at investigating the function and significance of CD110 expression in pancreatic cancer.

METHODS

We performed immunohistochemical staining for CD110 expression in tumor samples from 86 patients with pancreatic cancer. We evaluated clinical outcomes and other clinicopathological factors to determine the significance of CD110 on survival and liver metastasis. We examine thrombopoietin-CD110 signaling in cancer cell extravasation in vitro and in vivo. We investigated the effects of CD110 knockdown on liver metastasis in a splenic xenograft mouse model.

RESULTS

CD110 expression in cancer cells was associated with low-histological-grade invasive ductal carcinoma, and patients with high CD110 expression had poorer prognosis (P = 0.0003). High CD110 expression was an independent predictor of liver metastasis (P = 0.0422). Knockdown of CD110 expression significantly attenuated cell migration and invasion. Treatment with thrombopoietin promoted pancreatic cancer cell extravasation. In the presence of thrombopoietin, CD110 increased cell viability through the activation of the ERK-MYC signaling pathway. Knockdown of CD110 expression inhibited liver metastases in the mouse model.

CONCLUSIONS

CD110 promotes pancreatic cancer progression and it may serve as a predictive factor for liver metastasis.

LRG-1 promotes pancreatic cancer growth and metastasis via modulation of the EGFR/p38 signaling

BACKGROUND

The abnormal expression of leucine-rich-alpha-2-glycoprotein 1 (LRG-1) is reported to be associated with multiple malignancies, but its role in the progression of pancreatic ductal adenocarcinoma (PDAC) remains to be determined.

METHODS

The expression of LRG-1 was assessed in PDAC tissues by RT-PCR, Western blot and immunohistochemistry. LRG-1-silenced or overexpressed cell lines were constructed using shRNA or LRG-1-overexpressing plasmids. EdU incorporation assay, Transwell invasion and wound-healing assays were performed to evaluate the proliferation, invasion and migration of PDAC cells. In addition, protein expression of the mitogen-activated protein kinase (MAPK) pathway was detected using Western blot. Finally, Co-immunoprecipitation assay was conducted in search of the potential interaction between LRG-1 and epidermal growth factor receptor (EGFR).

RESULTS

The expression of LRG-1 in PDAC tissue was significantly higher than that in adjacent normal tissue, and high LRG-1 expression predicted poor survival and a late tumor stage. In addition, LRG-1 markedly promoted the viability, proliferation, migration and invasion of PDAC cells in vitro and facilitated tumor growth in vivo. More importantly, we revealed that these bioactivities of LRG-1 might result from its selective interaction with EGFR, which might further activate the p38/MAPK signaling pathways.

CONCLUSION

LRG-1 may prove to be a promising biomarker for predicting prognosis of PDAC patients. Inhibition of LRG-1 or its downstream pathway could be a potential therapeutic target for the treatment of PDAC.

Aurora kinase A induces chemotherapy resistance through revival of dormant cells in laryngeal squamous cell carcinoma

BACKGROUND

Chemotherapy resistance was an important tumor metastasis mechanism.

METHODS

Cell Counting Kit-8 assay and plate colony formation assay were applied to examine the proliferation of laryngeal squamous cell carcinoma (LSCC). Immunofluorescent staining and Western blotting were carried out to show the expression of related proteins. Wound healing, migration, and invasion assays were used to examine the mobility, migration, and invasion of LSCC.

RESULTS

Downregulated Aurora kinase A (AURKA) increased chemotherapy sensitivity and reduced the ability of mobility, migration, and invasion of Hep2 cells, while upregulated AURKA possessed opposite results. Hep2/5-Fu cells possessed dormancy-like properties and upregulated AURKA in Hep2/5-Fu cells (Hep2/5-Fu/AURKA cells) revived dormant state. Furthermore, Erk1/2 was restrained in Hep2/5-Fu cells and activated in Hep2/5-Fu/AURKA cells. Moreover, Erk1/2 accelerated the ability of mobility, migration, and invasion in Hep2/5-Fu/AURKA cells.

CONCLUSION

AURKA activated dormant state to induce chemotherapy resistance and promoted metastasis of LSCC through Erk1/2 pathway.

ERK1/2-mediated EGFR-signaling is required for TGFβ-induced lens epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) plays a critical role in the pathogenesis of fibrotic cataract. Transforming growth factor-beta (TGFβ) is a potent inducer of this fibrotic process in lens. Recent studies in cancer progression have shown that in addition to activating the canonical Smad signaling pathway, TGFβ can also transactivate the epidermal growth factor receptor (EGFR) to enhance invasive cell migration. The present study aims to elucidate the involvement of EGFR-signaling in TGFβ-induced EMT in LECs. Treatment with TGFβ2 induced transdifferentiation of LECs into myofibroblastic cells, typical of an EMT. TGFβ2 induced the phosphorylation of the EGFR and upregulation of Egfr and Hb-egf gene expression. Pharmacologic inhibition of EGFR-signaling using PD153035 inhibited TGFβ-induced EMT, including the upregulation of mesenchymal markers and downregulation of epithelial markers. Crosstalk between TGFβ2-induced EGFR and ERK1/2 was evident, with both pathways impacting on Smad2/3-signaling. Our finding that TGFβ2 transactivates downstream EGFR-signaling reveals a previously unknown mechanism in the pathogenesis of cataract. Understanding the complex interplay between divergent canonical and non-canonical signaling pathways, as well as downstream target genes involved in TGFβ-induced EMT, will enable the development of more effective targeted therapies in the pharmacological treatment of cataract.

EGF-Mediated Overexpression of Myc Attenuates miR-26b by Recruiting HDAC3 to Induce Epithelial-Mesenchymal Transition of Lens Epithelial Cells

The previous study has demonstrated that epidermal growth factor (EGF) and EGF receptor (EGFR) signaling plays a critical role in the development of posterior capsule opacification (PCO) through regulating lens epithelial cells (LECs) proliferation. Recent studies have suggested that the residual LECs undergo proliferation and migration, and epithelial-mesenchymal transition (EMT) is the important cause of PCO formation after cataract surgery. EMT of LECs is considered to be playing a central role in the pathogenesis of PCO. In the present study, we investigated whether and how EGF may regulate EMT of LECs. First, we demonstrated that EGF and EGFR signaling induces Myc overexpression in primary human lens epithelial cells (HLECs). In turn, Myc overexpression could inhibit miR-26b by recruitment of HDAC3. Consequently, the downregulated expression of miR-26b increased the expression of EZH2 in primary HLECs. Mechanistically, miR-26b directly controls EZH2 expression by targeting its 3′-UTR in HLECs by luciferase reporter assays. Finally, we demonstrated that EGF induces the expression of EMT markers in primary HLECs via a miR-26b-dependent mechanism. In summary, EGF activated Myc and Myc overexpression inhibited miR-26b by recruitment of HDAC3, which in turn induced the expression of EZH2 and promoted the progression of EMT in HLECs.

Downregulated miR-98-5p promotes PDAC proliferation and metastasis by reversely regulating MAP4K4

BACKGROUND

The aberrant expression of microRNAs (miRNAs) has emerged as important hallmarks of cancer. However, the molecular mechanisms underlying the differences of miRNA expression remain unclear. Many studies have reported that miR-98-5p plays vital functions in the development and progression of multiple cancers. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unknown.

METHODS

The expression of miR-98-5p and its specific target gene were determined in human PDAC specimens and cell lines by miRNA qRT-PCR, qRT-PCR and western blot. The effects of miR-98-5p depletion or ectopic expression on PDAC proliferation, migration and invasion were evaluated in vitro using CCK-8 proliferation assays, colony formation assays, wound healing assays and transwell assays. Furthermore, the in vivo effects were investigated using the mouse subcutaneous xenotransplantation and pancreatic tail xenotransplantation models. Luciferase reporter assays were employed to identify interactions between miR-98-5p and its specific target gene.

RESULTS

MiR-98-5p expression was significantly lower in cancerous tissues and associated with tumor size, TNM stage, lymph node metastasis and survival. Notably, a series of gain- and loss-of-function assays elucidated that miR-98-5p suppressed PDAC cell proliferation, migration and invasion both in vitro and in vivo. Luciferase reporter assays, western blot and qRT-PCR revealed MAP4K4 to be a direct target of miR-98-5p. The effects of ectopic miR-98-5p were rescued by MAP4K4 overexpression. In contrast, the effects of miR-98-5p depletion were impaired by MAP4K4 knockdown. Furthermore, miR-98-5p suppressed the MAPK/ERK signaling pathway through downregulation of MAP4K4. In addition, the expression level of miR-98-5p was negatively correlated with MAP4K4 expression in PDAC tissues and cell lines.

CONCLUSIONS

These results suggest that downregulation of miR-98-5p promotes tumor development by downregulation of MAP4K4 and inhibition of the downstream MAPK/ERK signaling, thus, highlighting the potential of miR-98-5p as a therapeutic target for PDAC.