PLOD2 regulated by transcription factor FOXA1 promotes metastasis in NSCLC

Hypoxia-induced PLOD2 regulates invasion and epithelial-mesenchymal transition in endometrial carcinoma cells

BACKGROUND

Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) was induced in hypoxia and participated in cancer development. However, the role of PLOD2 in endometrial carcinoma remains unclear.

OBJECTIVE

To explore the influences and regulation mechanism of PLOD2 in endometrial carcinoma under hypoxic condition.

METHODS

The small interfering RNA (siRNA) targeting to PLOD2 and pcDNA3.1-PLPD2 were transfected to endometrial carcinoma cells to alter PLOD2 expression. Cell proliferation ability was determined by colony formation assay. Wound healing assay used to detect cell migration ability. Transwell invasion assay was used to detect cell invasion ability.

RESULTS

PLOD2 and Hypoxia-inducible factor-1α (HIF-1α) were induced by hypoxia. Down-regulation of PLOD2 did not affect endometrial carcinoma cell proliferation ability, while inhibited cell migration, invasion under hypoxic condition. Besides, down-regulation of PLOD2 increased the levels of γ-catenin and E-cadherin and decreased levels of Fibronectin and Snail under hypoxic condition. Down-regulation of PLOD2 also inactivated Src and phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) signaling under hypoxic condition. The promoting effects of PLOD2 overexpression on migration, invasion and epithelial-mesenchymal transition (EMT) of endometrial carcinoma cells were reversed by Akt inhibitor (MK2206) under hypoxic condition.

CONCLUSION

PLOD2 expression was increased in endometrial carcinoma cells under hypoxic condition. PLOD2 modulated migration, invasion, and EMT of endometrial carcinoma cells via PI3K/Akt signaling. PLOD2 may be a potential therapeutic target for endometrial carcinoma.

PLOD2 promotes aerobic glycolysis and cell progression in colorectal cancer by upregulating HK2

The purpose of this study was to characterize the expression of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a membrane-bound homodimeric enzyme that specifically hydroxylates lysine in the telopeptide of procollagens, and assess the clinical significance of PLOD2 in colorectal cancer (CRC). Our results show that PLOD2 is highly expressed in CRC tumor tissues and cell lines, both at the mRNA and protein levels. Next, we found that PLOD2 was positively correlated with tumor grade (P = 0.001), T stage (P = 0.001), N stage (P < 0.001), and an advanced TNM stage (P < 0.001). Knockdown of PLOD2 attenuated CRC cell proliferation, migration, and invasiveness, in vitro. Our analysis of the mechanism behind the effects of PLOD2 suggests that PLOD2 affected glycolysis by regulating the expression of hexokinase 2 (HK2). HK2 reverses the inhibitory effects of PLOD2 knockdown in CRC. Furthermore, the data suggest that PLOD2 regulates the expression of HK2 via the STAT3 signaling pathway. Survival analysis revealed that high expression levels of PLOD2 (HR = 3.800, P < 0.001) and HK2 expression (HR = 10.222, P < 0.001) correlated with the overall survival rate. After analyzing their expression and correlation, PLOD2 positively correlated with HK2 (r = 0.590, P < 0.001). Our findings have revealed that PLOD2 is a novel regulatory factor in glucose metabolism, exerted via controlling HK2 expression in CRC cells, suggesting PLOD2 as a promising therapeutic target for CRC treatment.

Tumor-secreted PAI-1 promotes breast cancer metastasis via the induction of adipocyte-derived collagen remodeling

Background

Breast cancer cells recruit surrounding stromal cells, such as cancer-associated fibroblasts (CAFs), to remodel collagen and promote tumor metastasis. Adipocytes are the most abundant stromal partners in breast tissue, local invasion of breast cancer leads to the proximity of cancer cells and adipocytes, which respond to generate cancer-associated adipocytes (CAAs). These cells exhibit enhanced secretion of extracellular matrix related proteins, including collagens. However, the role of adipocyte-derived collagen on breast cancer progression still remains unclear.

Methods

Adipocytes were cocultured with breast cancer cells for 3D collagen invasion and collagen organization exploration. Breast cancer cells and adipose tissue co- implanted mouse model, clinical breast cancer samples analysis were used to study the crosstalk between adipose and breast cancer cells in vivo. A combination of proteomics, enzyme-linked immunosorbent assay, loss of function assay, qPCR, western blot, database analysis and chromatin immunoprecipitation assays were performed to study the mechanism mediated the activation of PLOD2 in adipocytes.

Results

It was found that CAAs remodeled collagen alignment during crosstalk with breast cancer cells in vitro and in vivo, which further promoted breast cancer metastasis. Tumor-derived PAI-1 was required to activate the expression of the intracellular enzyme procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) in CAAs. Pharmacologic blockade of PAI-1 or PLOD2 disrupted the collagen reorganization in CAAs. Mechanistically, it was observed that PI3K/AKT pathway was activated in adipocytes upon co-culturing with breast cancer cells or treatment with recombinant PAI-1, which could promote the translocation of transcription factor FOXP1 into the nucleus and further enhanced the promoter activity of PLOD2 in CAAs. In addition, collagen reorganization at the tumor-adipose periphery, as well as the positive relevance between PAI-1 and PLOD2 in invasive breast carcinoma were confirmed in clinical specimens of breast cancer.

Conclusion

In summary, our findings revealed a new stromal collagen network that favors tumor invasion and metastasis establish between breast cancer cells and surrounding adipocytes at the tumor invasive front, and identified PLOD2 as a therapeutic target for metastatic breast cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0373-z) contains supplementary material, which is available to authorized users.

DT-13 suppresses breast cancer metastasis by modulating PLOD2 in the adipocytes microenvironment

BACKGROUND

Metastasis is the main cause of death in breast cancer and previous researches have indicated the pivotal role of adipocytes in breast cancer metastasis. DT-13, the saponin monomer 13 of the Dwarf lilyturf tuber, has been proved to exert potential anti-metastatic effect, the detailed mechanisms have not been well elucidated and the role of DT-13 in modulating adipocyte-breast cancer microenvironment has been given little attention.

PURPOSE

This study aims to explore the mechanisms of DT-13 in inhibiting breast cancer metastasis and whether DT-13 inhibit breast cancer metastasis via modulating the interactions between adipocytes and breast cancer cells.

METHODS

The cytotoxic effect of DT-13 on breast cancer cell viability was detected by MTT assay. Migration assays was used to conduct the effect of DT-13 on breast cancer cells migration. Orthotopic xenograft tumor model was used to test the effect of DT-13 on breast cancer metastasis. qRT-PCR and Western blot were used to investigate the mechanisms of DT-13 inhibiting breast cancer metastasis.

RESULTS

DT-13 inhibited breast cancer cells migration at the concentration without cytotoxicity. Furthermore, DT-13 decreased PLOD2 expression through modulating JAK/STAT3 and PI3K/AKT signaling pathways directly or indirectly in the adipocyte-breast cancer microenvironment. Orthotopic implantation mouse model of breast cancer further confirmed that DT-13 inhibited breast cancer metastasis via downregulating PLOD2 in vivo.

CONCLUSION

DT-13 suppressed breast cancer metastasis via reducing the expression of PLOD2.

FOX-A1 contributes to acquisition of chemoresistance in human lung adenocarcinoma via transactivation of SOX5

Background

Chemoresistance is a major obstacle for the effective treatment of lung adenocarcinoma (LAD). Forkhead box (FOX) proteins have been demonstrated to play critical roles in promoting epithelial-mesenchymal transition (EMT) and chemoresistance. However, whether FOX proteins contribute to the acquisition of EMT and chemoresistance in LAD remains largely unknown.

Methods

FOX-A1 expression was measured in LAD cells and tissues by qRT-PCR. The expression levels of EMT markers were detected by western blotting and immunofluorescence assay. The interaction between Sex determining region Y-box protein 5 (SOX5) and FOX-A1 was validated by chromatin immunoprecipitation sequence (ChIP-seq) and Chromatin immunoprecipitation (ChIP) assay. Kaplan-Meier analysis and multivariate Cox regression analysis were performed to analyze the significance of FOX-A1 and SOX5 expression in the prognosis of LAD patients.

Findings

FOX-A1 was upregulated in docetaxel-resistant LAD cells. High FOX-A1 expression was closely associated with a worse prognosis. Upregulation of FOX-A1 in LAD samples indicated short progression-free survival (PFS) and overall survival (OS). SOX5 is a new and direct target of FOX-A1 and was positively regulated by FOX-A1 in LAD cell lines. Knockdown of FOX-A1 or SOX5 reversed the chemoresistance of docetaxel-resistant LAD cells by suppressing cell proliferation, migration and EMT progress.

Interpretation

These data elucidated an original FOX-A1/SOX5 pathway that represents a promising therapeutic target for chemosensitizing LAD and provides predictive biomarkers for evaluating the efficacy of chemotherapies.

Correlation between procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 and breast cancer

Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), which affects collagen synthesis, is associated with breast cancer. The purpose of the study is to detect the expression of PLOD2 in breast cancer and to evaluate the correlation between PLOD2 and clinicopathologic characteristics and prognosis of patients with breast cancer. 50 paired samples including breast cancer tissues and adjacent non-tumor tissues were formalin-fixed and evaluated by immunohistochemistry. The results revealed that PLOD2 expression in breast cancer tissues was much higher than that in tissues adjacent to breast cancer. High expression of PLOD2 was positively associated with tumor stage (P = 0.003) and lymph node metastasis (P = 0.001). However, high expression of PLOD2 was negatively related to Ki-67 (P < 0.001) while positively related to progesterone receptor (PR) (P = 0.001). PLOD2 expression was positively related to the metastasis of breast cancer. Therefore, high expression of PLOD2 was identified as a poor prognostic biomarker for patients with breast cancer. These results suggest a novel molecular mechanism in breast cancer tumorigenesis, thus providing a potential therapeutic target of breast cancer.

PLOD3 suppression exerts an anti-tumor effect on human lung cancer cells by modulating the PKC-delta signaling pathway

Current lung cancer treatments are far from satisfactory; thus, finding novel treatment targets is crucial. We recently identified procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3 (PLOD3), which is involved in fibrosis and tissue remodeling as a radioresistance-related protein in lung cancer cells; however, its mechanism is unclear. In this study, we designed human PLOD3-specific short interfering (si)RNAs and tested their effects on tumor growth inhibition in vitro and in vivo. PLOD3 knockdown overcame chemoresistance and decreased radioresistance by inducing caspase-3-dependent apoptosis in lung cancer cells. Furthermore, PLOD3 interacted with PKCδ to activate caspase-2,4-dependent apoptosis through ER-stress-induced IRE1α activation and the downstream unfolded-protein response pathway. In a mouse xenograft model, PLOD3 knockdown promoted radiation-induced tumor growth inhibition, without side effects. Moreover, lung cancer patients with high PLOD3 expression showed poorer prognosis than those with low PLOD3 expression upon radiotherapy, suggesting that PLOD3 promotes tumor growth. Therefore, PLOD3 siRNA suppresses radioresistance and chemoresistance by inducing apoptosis and renders PLOD3 as a candidate lung cancer biomarker. PLOD3 gene therapy might enhance the efficacy of radiotherapy or chemotherapy in lung cancer patients.

Adipocyte-derived IL-6 and leptin promote breast Cancer metastasis via upregulation of Lysyl Hydroxylase-2 expression

BACKGROUND

Adipocytes make up the major component of breast tissue, accounting for 90% of stromal tissue. Thus, the crosstalk between adipocytes and breast cancer cells may play a critical role in cancer progression. Adipocyte-breast cancer interactions have been considered important for the promotion of breast cancer metastasis. However, the specific mechanisms underlying these interactions are unclear. In this study, we investigated the mechanisms of adipocyte-mediated breast cancer metastasis.

METHODS

Breast cancer cells were cocultured with mature adipocytes for migration and 3D matrix invasion assays. Next, lentivirus-mediated loss-of-function experiments were used to explore the function of lysyl hydroxylase (PLOD2) in breast cancer migration and adipocyte-dependent migration of breast cancer cells. The role of PLOD2 in breast cancer metastasis was further confirmed using orthotopic mammary fat pad xenografts in vivo. Clinical samples were used to confirm that PLOD2 expression is increased in tumor tissue and is associated with poor prognosis of breast cancer patients. Cells were treated with cytokines and pharmacological inhibitors in order to verify which adipokines were responsible for activation of PLOD2 expression and which signaling pathways were activated in vitro.

RESULTS

Gene expression profiling and Western blotting analyses revealed that PLOD2 was upregulated in breast cancer cells following coculture with adipocytes; this process was accompanied by enhanced breast cancer cell migration and invasion. Loss-of-function studies indicated that PLOD2 knockdown suppressed cell migration and disrupted the formation of actin stress fibers in breast cancer cells and abrogated the migration induced by following coculture with adipocytes. Moreover, experiments performed in orthotopic mammary fat pad xenografts showed that PLOD2 knockdown could reduce metastasis to the lung and liver. Further, high PLOD2 expression correlated with poor prognosis of breast cancer patients. Mechanistically, adipocyte-derived interleukin-6 (IL-6) and leptin may facilitate PLOD2 upregulation in breast cancer cells and promote breast cancer metastasis in tail vein metastasis assays. Further investigation revealed that adipocyte-derived IL-6 and leptin promoted PLOD2 expression through activation of the JAK/STAT3 and PI3K/AKT signaling pathways.

CONCLUSIONS

Our study reveals that adipocyte-derived IL-6 and leptin promote PLOD2 expression by activating the JAK/STAT3 and PI3K/AKT signaling pathways, thus promoting breast cancer metastasis.

Expression levels and co‑targets of miRNA‑126‑3p and miRNA‑126‑5p in lung adenocarcinoma tissues: Αn exploration with RT‑qPCR, microarray and bioinformatic analyses

Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer. Previous studies have found that many microRNAs (miRNAs), including miRNA-126-3p, may play a critical role in the development of LUAD. However, no study of LUAD has researched the synergistic effects and co-targets of both miRNA-126-3p and miRNA-126-5p. The present study used real-time quantitative polymerase chain reaction (RT-qPCR) to explore the expression values of miRNA-126-3p and miRNA-126-5p in 101 LUAD and 101 normal lung tissues. Ten relevant microarray datasets were screened to further validate the expression levels of miRNA-126-3p and −5p in LUAD. Twelve prediction tools were employed to obtain potential targets of miRNA-126-3p and miRNA-126-5p. The results showed that both miRNA-126-3p and −5p were expressed significantly lower in LUAD. A significant positive correlation was also present between miRNA-126-3p and −5p expression in LUAD. In addition, lower expression of miRNA-126-3p and −5p was indicative of vascular invasion, lymph node metastasis (LNM), and a later tumor/node/metastasis (TNM) stage of LUAD. The authors obtained 167 targets of miRNA-126-3p and 212 targets of miRNA-126-5p; 44 targets were co-targets of both. Eight co-target genes (IGF2BP1, TRPM8, DUSP4, SOX11, PLOD2, LIN28A, LIN28B and SLC7A11) were initially identified as key genes in LUAD. The results of the present study indicated that the co-regulation of miRNA-126-3p and miRNA-126-5p plays a key role in the development of LUAD, which also suggests a fail-proof mode between miRNA-3p and miRNA-126-5p.

The high expression of FOXA1 is correlated with a favourable prognosis in salivary duct carcinomas: a study of 142 cases

AIMS

Salivary duct carcinoma (SDC) is an uncommon, aggressive tumour that, histologically, resembles high-grade mammary ductal carcinoma, and is characterised by the expression of androgen receptor (AR). The androgen signalling pathway, a potential therapeutic target, can be regulated by FOXA1. This study aimed to evaluate the clinicopathological implications of FOXA1 in SDC.

METHODS AND RESULTS

We examined the relationship between the immunoexpression of FOXA1 and FOXA1 mutations and clinicopathological factors, including the biomarker status and clinical outcome, in 142 SDCs. FOXA1 was expressed in 128 SDCs (90.1%); the immunoexpression was heterogeneous. SDCs with a higher FOXA1 labelling index (LI) (≥20%) more frequently showed less advanced tumors on T classification (P = 0.002). FOXA1 LI was correlated positively with the AR expression value (r = 0.430, P < 0.001). PI3K and p-mTOR positivity, and intact-PTEN, were associated with a higher FOXA1 LI. Twenty-two of 121 SDCs (18.2%) harboured FOXA1 gene mutations at the flanking regions in and around the forkhead DNA binding domain; however, the given gene mutation and the expression of FOXA1 were not significantly correlated. A multivariate analysis revealed that SDCs with a higher FOXA1 LI were associated with longer overall survival and progression-free survival (P = 0.029 and 0.016, respectively).

CONCLUSIONS

In SDC, FOXA1, which may biologically interact with the AR and PI3K signalling pathways, is a putative biomarker that may be associated with a favourable prognosis. Further studies are needed to apply the findings to the development of targeted personalised therapy for patients with SDC.

Comprehensive Phenotypic Characterization of Human Invasive Lobular Carcinoma Cell Lines in 2D and 3D Cultures

Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer following invasive ductal carcinoma (IDC) and characterized by the loss of E-cadherin-mediated adherens junctions. Despite displaying unique histologic and clinical features, ILC still remains a chronically understudied disease, with limited knowledge gleaned from available laboratory research models. Here we report a comprehensive 2D and 3D phenotypic characterization of four estrogen receptor-positive human ILC cell lines: MDA-MB-134, SUM44, MDA-MB-330, and BCK4. Compared with the IDC cell lines MCF7, T47D, and MDA-MB-231, ultra-low attachment culture conditions revealed remarkable anchorage independence unique to ILC cells, a feature not evident in soft-agar gels. Three-dimensional Collagen I and Matrigel culture indicated a generally loose morphology for ILC cell lines, which exhibited differing preferences for adhesion to extracellular matrix proteins in 2D. Furthermore, ILC cells were limited in their ability to migrate and invade in wound-scratch and transwell assays, with the exception of haptotaxis to Collagen I. Transcriptional comparison of these cell lines confirmed the decreased cell proliferation and E-cadherin-mediated intercellular junctions in ILC while uncovering the induction of novel pathways related to cyclic nucleotide phosphodiesterase activity, ion channels, drug metabolism, and alternative cell adhesion molecules such as N-cadherin, some of which were differentially regulated in ILC versus IDC tumors. Altogether, these studies provide an invaluable resource for the breast cancer research community and facilitate further functional discoveries toward understanding ILC, identifying novel drug targets, and ultimately improving the outcome of patients with ILC.Significance: These findings provide the breast cancer research community with a comprehensive assessment of human invasive lobular carcinoma (ILC) cell line signaling and behavior in various culture conditions, aiding future endeavors to develop therapies and to ultimately improve survival in patients with ILC. Cancer Res; 78(21); 6209-22. ©2018 AACR.

Roles of PLODs in Collagen Synthesis and Cancer Progression

Collagen is the major component of extracellular matrix. Collagen cross-link and deposition depend on lysyl hydroxylation, which is catalyzed by procollagen-lysine, 2-oxoglutarate 5-dioxygenase (PLOD). Aberrant lysyl hydroxylation and collagen cross-link contributes to the progression of many collagen-related diseases, such as fibrosis and cancer. Three lysyl hydroxylases (LH1, LH2, and LH3) are identified, encoded by PLOD1, PLOD2, and PLOD3 genes. Expression of PLODs is regulated by multiple cytokines, transcription factors and microRNAs. Dysregulation of PLODs promotes cancer progression and metastasis, suggesting that targeting PLODs is potential strategy for cancer treatment. Here, we summarize the recent progress in the investigation of function and regulation of PLODs in normal tissue development and disease progression, especially in cancer.

Silibinin Inhibits NSCLC Metastasis by Targeting the EGFR/LOX Pathway

Tumor metastasis is the most lethal and debilitating process that threatens cancer patients. Among the regulators involved in tumor metastasis, lysyl oxidase (LOX) is an important contributor for tumor invasion, migration and the formation of the pre-metastatic niche. Although the relationship between LOX and poor prognosis of lung patients has been preliminary reported, the mechanism remains poorly understood. Here, we found that LOX overexpression is closely related to the survival of lung adenocarcinoma patients but not squamous cell carcinoma patients. Moreover, we confirmed that LOX expression is regulated by the activation of epidermal growth factor receptor (EGFR) via the PI3K/AKT, MEK/ERK, and SAPK/JNK signaling pathways in non-small cell lung cancer (NSCLC). Meanwhile, the study also suggested that the traditional anti-fibrosis drug silibinin inhibited NSCLC cell migration in an EGFR/LOX dependent manner. In addition, an orthotopic implantation metastasis model also confirmed that the EGFR inhibitor WZ4002 and silibinin decreased tumor metastasis through the EGFR/LOX pathway. Altogether, this study revealed that LOX expression is regulated by the EGFR pathway and this may account for the anti-cancer metastasis effects of silibinin, indicating LOX as a potentially therapeutic target for NSCLC treatment.