Striatins and STRIPAK complex partners in clinical outcomes of patients with breast cancer and responses to drug treatment.

Objective: Striatins (STRNs) family, which contains three multi-domain scaffolding proteins, are cornerstones of the striatins interacting phosphatase and kinase (STRIPAK) complex. Although the role of the STRIPAK complex in cancer has become recognized in recent years, its clinical significance in breast cancer has not been fully established. Methods: Using a freshly frozen breast cancer tissue cohort containing both cancerous and adjacent normal mammary tissues, we quantitatively evaluated the transcript-level expression of all members within the STRIPAK complex along with some key interacting and regulatory proteins of STRNs. The expression profile of each molecule and the integrated pattern of the complex members were assessed against the clinical-pathological factors of the patients. The Cancer Genome Atlas (TCGA) dataset was used to evaluate the breast cancer patients' response to chemotherapies. Four human breast cancer cell lines, MDA-MB-231, MDA-MB-361, MCF-7, and SK-BR-3, were subsequently adopted for in vitro work. Results: Here we found that high-level expressions of STRIP2, calmodulin, CCM3, MINK1 and SLMAP were respectively associated with shorter overall survival (OS) of patients. Although the similar pattern observed for STRN3, STRN4 and a contrary pattern observed for PPP2CA, PPP2CB and PPPR1A were not significant, the integrated expression profile of STRNs group and PPP2 group members constitutes a highly significant prognostic indicator for OS [P<0.001, hazard ratio (HR)=2.04, 95% confidence interval (95% CI), 1.36-3.07] and disease-free survival (DFS) (P=0.003, HR=1.40, 95% CI, 1.12-1.75). Reduced expression of STRN3 has an influence on the biological functions including adhesiveness and migration. In line with our clinical findings, the breast cancer cells responded to STRN3 knockdown with changes in their chemo-sensitivity, of which the response is also breast cancer subtype dependent. Conclusions: Our results suggest a possible role of the STRIPAK complex in breast cancer development and prognosis. Among the members, the expression profile of STRN3 presents a valuable factor for assessing patients' responses to drug treatment.

Gastrointestinal Bleeding in Patients With Coronavirus Disease 2019: A Matched Case-Control Study.

INTRODUCTION: Although current literature has addressed gastrointestinal presentations including nausea, vomiting, diarrhea, abnormal liver chemistries, and hyperlipasemia as possible coronavirus disease 2019 (COVID-19) manifestations, the risk and type of gastrointestinal bleeding (GIB) in this population is not well characterized. METHODS: This is a matched case-control (1:2) study with 41 cases of GIB (31 upper and 10 lower) in patients with COVID-19 and 82 matched controls of patients with COVID-19 without GIB. The primary objective was to characterize bleeding etiologies, and our secondary aim was to discuss outcomes and therapeutic approaches. RESULTS: There was no difference in the presenting symptoms of the cases and controls, and no difference in severity of COVID-19 manifestations (P > 0.05) was observed. Ten (32%) patients with upper GIB underwent esophagogastroduodenoscopy and 5 (50%) patients with lower GIBs underwent flexible sigmoidoscopy or colonoscopy. The most common upper and lower GIB etiologies were gastric or duodenal ulcers (80%) and rectal ulcers related to rectal tubes (60%), respectively. Four of the esophagogastroduodenoscopies resulted in therapeutic interventions, and the 3 patients with rectal ulcers were referred to colorectal surgery for rectal packing. Successful hemostasis was achieved in all 7 cases that required interventions. Transfusion requirements between patients who underwent endoscopic therapy and those who were conservatively managed were not significantly different. Anticoagulation and rectal tube usage trended toward being a risk factor for GIB, although it did not reach statistical significance. DISCUSSION: In COVID-19 patients with GIB, compared with matched controls of COVID-19 patients without GIB, there seemed to be no difference in initial presenting symptoms. Of those with upper and lower GIB, the most common etiology was peptic ulcer disease and rectal ulcers from rectal tubes, respectively. Conservative management seems to be a reasonable initial approach in managing these complex cases, but larger studies are needed to guide management.

Tim-3 promotes cell aggressiveness and paclitaxel resistance through NF-κB/STAT3 signalling pathway in breast cancer cells.

OBJECTIVE: Although T-cell immunoglobulin and mucin-domain containing molecule-3 (Tim-3) has been recognized as a promising target for cancer immunotherapy, its exact role in breast cancer has not been fully elucidated. METHODS: Tim-3 gene expression in breast cancer and its prognostic significance were analyzed. Associated mechanisms were then explored in vitro by establishing Tim-3-overexpressing breast cancer cells. RESULTS: In a pooled analysis of The Cancer Genome Atlas (TCGA) database, Tim-3 gene expression levels were significantly higher (P<0.001) in breast cancer tissue, compared with normal tissues. Tim-3 was a prognosis indicator in breast cancer patients [relapse-free survival (RFS), P=0.004; overall survival (OS), P=0.099]. Tim-3 overexpression in Tim-3low breast cancer cells promoted aggressiveness of breast cancer cells, as evidenced by enhanced proliferation, migration, invasion, tight junction deterioration and tumor-associated tubal formation. Tim-3 also enhanced cellular resistance to paclitaxel. Furthermore, Tim-3 exerted its function by activating the NF-κB/STAT3 signalling pathway and by regulating gene expression [cyclin D1 (CCND1), C-Myc, matrix metalloproteinase-1(MMP1), TWIST, vascular endothelial growth factor (VEGF) upregulation, concomitant with E-cadherin downregulation). Lastly, Tim-3 downregulated tight junction-associated molecules zona occludens (ZO)-2, ZO-1 and occludin, which may further facilitate tumor progression. CONCLUSIONS: Tim-3 plays an oncogenic role in breast cancer and may represent a potential target for antitumor therapy.

PAK5 mediates cell: cell adhesion integrity via interaction with E-cadherin in bladder cancer cells.

Urothelial bladder cancer is a major cause of morbidity and mortality worldwide, causing an estimated 150 000 deaths per year. Whilst non-muscle-invasive bladder tumours can be effectively treated, with high survival rates, many tumours recur, and some will progress to muscle-invasive disease with a much poorer long-term prognosis. Thus, there is a pressing need to understand the molecular transitions occurring within the progression of bladder cancer to an invasive disease. Tumour invasion is often associated with a down-regulation of E-cadherin expression concomitant with a suppression of cell:cell junctions, and decreased levels of E-cadherin expression have been reported in higher grade urothelial bladder tumours. We find that expression of E-cadherin in a panel of bladder cancer cell lines correlated with the presence of cell:cell junctions and the level of PAK5 expression. Interestingly, exogenous PAK5 has recently been described to be associated with cell:cell junctions and we now find that endogenous PAK5 is localised to cell junctions and interacts with an E-cadherin complex. Moreover, depletion of PAK5 expression significantly reduced junctional integrity. These data suggest a role for PAK5 in maintaining junctional stability and we find that, in both our own patient samples and a commercially available dataset, PAK5mRNA levels are reduced in human bladder cancer compared with normal controls. Taken together, the present study proposes that PAK5 expression levels could be used as a novel prognostic marker for bladder cancer progression.

Neural Wiskott-Aldrich syndrome protein (nWASP) is implicated in human lung cancer invasion.

Lung cancer is one of the most commonly diagnosed cancers with survival much lower in patients diagnosed with distal metastases. It is therefore imperative to identify pathways involved in lung cancer invasion and metastasis and to consider the therapeutic potential of agents that can interfere with these molecular pathways. This study examines nWASP expression in human lung cancer tissues and explores the effect of nWASP inhibition and knockdown on lung cancer cell behaviour. METHODS: QPCR has been used to measure nWASP transcript expression in human lung cancer tissues. The effect of wiskostatin, an nWASP inhibitor, on A-549 and SK-MES-1 lung carcinoma cell growth, adhesion, migration and invasion was also examined using several in vitro functional assays, including ECIS, and immunofluorescence staining. The effect of nWASP knockdown using siRNA on particular behaviours of lung cancer cells was also examined. RESULTS: Patients with high levels of nWASP expression in tumour tissues have significantly lower survival rates. nWASP transcript levels were found to correlate with lymph node involvement (p = 0.042). nWASP inhibition and knockdown was shown to significantly impair lung cancer cell growth. nWASP inhibition also affected other cell behaviours, in SK-MES-1 invasion and A-549 cell motility, adhesion and migration. Paxillin and FAK activity are reduced in lung cancer cell lines following wiskostatin and nWASP knockdown as shown by immunofluorescence and western blot. CONCLUSIONS: These findings highlight nWASP as an important potential therapeutic target in lung cancer invasion and demonstrate that inhibiting nWASP activity using the inhibitor wiskostatin can significantly alter cell behaviour in vitro.

The role of tight junctions in cancer metastasis.

Over the last decade, it has become apparent that the tight junction (TJ) is a key component in tumour progression and metastasis. In addition to its role in the control of paracellular diffusion of ions and certain molecules, the TJ has a vital role in maintaining cell to cell adhesion and tissue integrity. Changes in the expression and/or distribution of TJ proteins can result in loss in cohesion of the TJ structure, which in turn results in the ability of cancer cells to become invasive and then ultimately lead to the metastasis of cancer cells. This review will discuss recent insights into how TJ are involved in the process of tumour metastasis.

Metastatic Lymph Node 64 (MLN64) Expression in Gastric Cancer: The Clinical and Molecular Implications in Drug Resistance.

BACKGROUND/AIM: Metastatic lymph node 64 (MLN64) is often co-amplified with ERBB2 (HER2) and plays a role in the progression of breast and prostate cancer. The present study explored the expression of MLN64 in clinical gastric cancer in association with the ERBB family and its impact on drug resistance in patients. MATERIALS AND METHODS: Two independent gastric cancer cohorts (n=324; n=87) were used to explore the expression profile of MLN64 in conjunction with ERBB family members in clinical gastric cancer and its association with neoadjuvant chemotherapy responses. Gastric cancer AGS and HCG27 cells with MLN64 knockdown were generated to determine the function of MLN64 in cell behavioural changes. RESULTS: Gastric tumor tissues expressed significantly higher levels of MLN64 compared with normal tissues (p<0.01); however, MLN64 alone was a weak prognostic indicator. An integrated co-expression of MLN64, ERBB4, and NRG4 was a significant factor in assessing overall survival in both cohorts. MLN64 was a profound indicator of patient response to neoadjuvant chemotherapy. In vitro studies indicated a significant contribution of MLN64 to the response of gastric cancer cells to chemodrugs and Her-2 inhibitors. MLN64 knockdown also contributed to the adhesion and migration and suggested a possible mechanism mediated by the interaction between MLN64 and ERBBs. CONCLUSION: MLN64 is an indicator of patient response to neoadjuvant chemotherapy in gastric cancer. Together with the expression pattern of ERBB4, MLN64 is a poor prognostic factor for patients with gastric cancer.

Cellular Impacts of Striatins and the STRIPAK Complex and Their Roles in the Development and Metastasis in Clinical Cancers (Review).

Striatins (STRNs) are generally considered to be cytoplasmic proteins, with lower expression observed in the nucleus and at cell-cell contact regions. Together with protein phosphatase 2A (PP2A), STRNs form the core region of striatin-interacting phosphatase and kinase (STRIPAK) complexes through the coiled-coil region of STRN proteins, which is crucial for substrate recruitment. Over the past two decades, there has been an increasing amount of research into the biological and cellular functions of STRIPAK members. STRNs and the constituent members of the STRIPAK complex have been found to regulate several cellular functions, such as cell cycle control, cell growth, and motility. Dysregulation of these cellular events is associated with cancer development. Importantly, their roles in cancer cells and clinical cancers are becoming recognised, with several STRIPAK components found to have elevated expression in cancerous tissues compared to healthy tissues. These molecules exhibit significant diagnostic and prognostic value across different cancer types and in metastatic progression. The present review comprehensively summarises and discusses the current knowledge of STRNs and core STRIPAK members, in cancer malignancy, from both cellular and clinical perspectives.

nWASP Inhibition Increases Wound Healing via TrKb/PLCγ Signalling.

(1) Background: Chronic wounds represent a major burden to patients and healthcare systems and identifying new therapeutic targets to encourage wound healing is a significant challenge. This study evaluated nWASP as a new therapeutic target in human wound healing and determined how this can be regulated. (2) Methods: Clinical cohorts from patients with chronic wounds were tested for the expression of nWASP and cell models were employed to evaluate the influence of nWASP on cellular functions that are key to the healing process following knockdown and/or the use of nWASP-specific inhibitors. (3) Results: nWASP was significantly elevated at transcript levels in human non-healing chronic wounds versus healing tissues. nWASP inhibitors, wiskostatin and 187-1, along with the knockdown of nWASP, modified both HaCaT and HECV cell behaviour. We then identified two signalling pathways affected by nWASP inhibition: TrkB signalling and downstream PLCγ1 phosphorylation were impaired by nWASP inhibition in HaCaT cells. The healing of wounds in a diabetic murine model was significantly improved with an nWASP inhibitor treatment. (4) Conclusions: This study showed that nWASP activity was related to the non-healing behaviour of chronic wounds and together with the findings in the in vivo models, it strongly suggested nWASP as a therapeutic target in non-healing wounds that are regulated via TrkB and PLCγ1 signalling.

Claudin-10 in the Blood Brain Barrier Function of Cerebral Endothelial Cells and Transendothelial Invasion of Breast Cancer Cells.

BACKGROUND/AIM: Claudin-10 (CLDN10) is a membrane integral protein. It is one of the widely expressed tight junctional claudins with functions not well defined. In the present study, the expression profile and its role in cerebral endothelial cells and in the interaction between breast cancer and endothelial cells were investigated. MATERIALS AND METHODS: CLDN10 expression was examined in a wide range of cell types. Brain endothelial cell models with or without CLDN10 expression were generated using the hCMEC/D3 cell line and used to test the barrier and permeability functions. Transendothelial drug delivery and invasion were also evaluated. RESULTS: hCMEC/D3 cells express high levels of CLDN10, compared with peripheral endothelial cells, mesothelial cells, fibroblasts, and breast cancer cells, which were either negative or expressed low levels of CLDN10. Knockdown of CLDN10 in hCMEC/D3 cells resulted in impaired tight junctions as seen by reduced transendothelial electric resistance and paracellular permeability. It also accelerated invasion of breast cancer cells through the endothelial cell layer. CLDN10 knockdown in hCMEC/D3 cells led to an increase in transendothelial chemodrug delivery. Furthermore, the SRC kinase inhibitor (AZM475271) was able to decrease the impedance and increase the paracellular permeability in cerebral endothelial cells. CONCLUSION: Cerebral endothelial cells express high levels of CLDN10, a protein regulating barrier function and thereby drug permeability and cancer invasiveness in brain endothelial cells, suggesting that it is a novel therapeutic target for the treatment of brain metastasis-related diseases.

Expression of Claudin-9 (CLDN9) in Breast Cancer, the Clinical Significance in Connection with Its Subcoat Anchorage Proteins ZO-1 and ZO-3 and Impact on Drug Resistance.

(1) Introduction: Claudin-9 (CLDN9) is a member of the claudin protein family, a critical transmembrane protein family for tight junctions that are implemented in the progression of numerous cancer types. The present study investigated the role that CLDN9, along with the subcoat proteins, Zonula Occludens (ZOs), plays in clinical breast cancer and subsequent impact on drug response of patients. (2) Methods: CLDN9 protein and CLDN9 transcript were determined and correlated with clinical and pathological indicators, together with the status of hormonal receptors. The levels of CLDN9 transcript were also assessed against the therapeutic responses of the patients to chemotherapies by using a dataset from the TCGA database. Breast cancer cell models, representing different molecular subtypes of breast cancer, with differential expression of CLDN9 were created and used to assess the biological impact and response to chemotherapeutic drugs. (3) Results: Breast cancer tissues expressed significantly higher levels of the CLDN9, with the high levels being associated with shorter survival. CLDN9 was significantly correlated with its anchorage proteins ZO-1 and ZO-3. Integrated expression of CLDN9, ZO-1 and ZO-3 formed a signature that was significantly linked to overall survival (OS) (p = 0.013) and relapse-free survival (RFS) (p = 0.024) in an independent matter. CLDN9 transcript was significantly higher in patients who were resistant to chemotherapies (p < 0.000001). CLDN9 connection to chemoresistance was particularly prominent in patients of ER-positive (ER(+)), Her-2-negative((Her-2(-)), ER(+)/Her-2(-) and triple-negative breast cancers (TNBCs), but not in patients with HER-2-positive tumors. In Her-2-negative MCF7 and MDA-MB-231 cancer cells, loss of CLDN9 significantly increased sensitivity to several chemotherapeutic drugs including paclitaxel, gemcitabine and methotrexate, which was not seen in Her-2(+) SKBR3 cells. However, suppressing Her-2 using neratinib, a permanent Her-2 inhibitor, sensitized cellular response to these chemodrugs in cells with CLDN9 knockdown. (4) Conclusions: CLDN9 is an important prognostic indicator for patients with breast cancer and also a pivotal factor in assessing patient responses to chemotherapies. Her-2 is a negating factor for the treatment response prediction value by CLDN9 and negating Her-2 and CLDN9 may enhance breast cancer cellular response to chemotherapeutic drugs.

Death associated protein­3 (DAP3) and DAP3 binding cell death enhancer­1 (DELE1) in human colorectal cancer, and their impacts on clinical outcome and chemoresistance.

Death associated protein­3 (DAP3) was identified as a responsive protein to interferon­gamma­induced cell death which possibly exerts this regulation by interacting with DAP3 binding cell Death enhancer­1 (DELE1), a newly discovered mitochondrial stress protein in response to cell stress signals. Whilst DAP3 has been shown to be aberrantly expressed in several cancer types (i.e. breast cancer), little is known about the relationship between DAP3 and DELE1 in cancers. The present study examined the expression levels of both DAP3 and DELE1 in clinical colorectal cancers (CRCs), as well as their implication on chemoresistance and mechanism behind the action. Firstly, transcript levels of both DAP3 and DELE1 were quantitatively assessed in a clinical cohort of CRC (n=94). Tumour tissues had significantly higher levels of DAP3, but not DELE1 compared with normal tissues. Levels of DAP3 and DELE1 had a significant association with patient's clinical outcomes and local recurrence. DAP3 and DELE1 significantly correlated in normal colorectal tissues but not in tumour tissues. Secondly, the protein levels of DAP3 and DELE1 were evaluated in both normal and tumour colon tissues which showed that both proteins were highly aberrant in CRC tissues. In addition, both DAP3 and DELE1 at transcript and protein levels were identified as prognostic factors for patient's clinical outcomes. Furthermore, in in vitro assays, knocking down DAP3 or DELE1, and in particular both DAP3 and DELE1 together rendered the CRC cells more sensitive to chemotherapy drugs, consistent with clinical findings of the TCGA­COAD datasets. The acquisition of drug sensitivity following the genetic knockdown was independent of the mitochondrial metabolism, as neither DAP3 knockdown nor DELE1 knockdown showed a significant change. In summary, DAP3 and DELE1 are highly aberrant in CRCs, and both molecules are prognostic factors for patient's clinical outcomes and local recurrence, and are indicators for chemoresistance.

Claudin-5 participates in the regulation of endothelial cell motility.

A key step in metastasis is the interaction and penetration of the vascular endothelium by cancer cells. Tight Junctions (TJ) are located between the cancer epithelial cells and between the endothelial cells functioning in an adhesive manner. They represent a critical barrier which the cancer cells must overcome in order to penetrate and initiate metastasis. Claudin-5 is a protein member of the Claudin family, a group of TJ proteins expressed in both endothelial and epithelial cells. This study examined in vitro the effect of altering levels of expression of Claudin-5 in HECV cells. Insertion of Claudin-5 gene in HECV cells resulted in cells that were significantly less motile and less adhesive to matrix (P < 0.001). These cells also exhibited a significant decreased in the angiogenic potential (P < 0.001). Results also revealed a link between Claudin-5 and cell motility. Furthermore, a possible link between Claudin-5 and N-WASP, and Claudin-5 and ROCK was demonstrated when interactions between these proteins were seen in the cell line. Moreover, followed by treatment of N-WASP inhibitor (Wiskostatin) and ROCK inhibitor (Y-27632), cell motility and angiogenic potential were assessed in response to the inhibitors. Results showed that the knockdown of Claudin-5 in HECV cells masked their response to both N-WASP and ROCK inhibitors. In conclusion, this study portrays a new and interesting role for Claudin-5 in cell motility involving the N-WASP and ROCK signalling cascade which is beyond the primarily role of Claudin-5 in keeping the cell barrier tight as it was originally reported.

Hepatitis A Virus Cellular Receptor 1 (HAVcr-1) Initiates Prostate Cancer Progression in Human Cells via Hepatocyte Growth Factor (HGF)-Induced Changes in Junctional Integrity.

BACKGROUND: HAVcR-1 has been linked to cancer aetiology and may regulate junctional complexes, with its role in prostate cancer still unexplored. This study aims to investigate the expression of HAVcR-1 in prostate cancer samples and the exploration of the cellular/molecular impact of HAVcR-1. METHODS: Levels of HAVcR-1 ectodomain in the serum of prostate cancer patients were compared to healthy controls, and assessed as the total protein and gene expression of HAVcR-1 and tissues sections. The manipulation of HAVcR-1 levels within prostate cancer cell lines determined changes in cell behaviour using in vitro cell models and barrier function assays. Protein/phosphoprotein levels were assessed using Western blotting. RESULTS: Levels of HAVcR-1 ectodomain from serum were decreased in patients with prostate cancer. Ectodomain levels correlated with the Gleason score. Histologically, the total protein/gene expression of HAVcR-1 was overexpressed in prostate cancer. The overexpression of HAVcR-1 in prostate cancer cell lines resulted in key changes in cell behaviour and the phosphorylation of ß-catenin with a concurrent decrease in membranous E-cadherin, increased nuclear ß-catenin and increased cyclin D1 protein expression, which were associated with HGF-promoted changes in the barrier function. CONCLUSIONS: HAVcR-1 expression and ectodomain release coincides with the presence of prostate cancer; thus, indicating HAVcR-1 as a potential biomarker to aid in diagnostics, and implicating HAVcR-1 in the dysregulation of junctional complexes.

EPLIN is a negative regulator of prostate cancer growth and invasion.

PURPOSE: We investigated the importance of EPLIN, a cytoskeletal associated protein implicated in cancer, in clinical prostate cancer and its role in the PC-3 prostate cancer cell line (ATCC™). MATERIALS AND METHODS: Full-length human EPLIN cDNA was cloned into a pEF6 expression vector and used to transfect the PC-3 human prostate cancer cell line. Cells over expressing EPLIN were termed PC-3(EPLIN EXP) while wild-type and empty pEF6 vector control cells were designated PC-3(WT) and PC-3(pEF6), respectively. The in vitro and in vivo impact of EPLIN on PC-3 cells was examined using a number of model assays. RESULTS: EPLIN over expression in PC-3 cells resulted in a decrease in the growth rate of this cell line (mean ± SD 0.6 ± 0.17 for PC-3(pEF6) cells vs 0.33 ± 0.01 for PC-3(EPLIN EXP) cells, p <0.01). PC-3(EPLIN EXP) cells were significantly less able to adhere to extracellular matrix than control cells (mean 61.0 ± 12.4 vs 102.8 ± 20.7, p = 0.028). Immunofluorescence staining showed an increased staining profile for paxillin in PC-3(EPLIN EXP) cells compared to wild-type cells. CONCLUSIONS: EPLIN over expression in the PC-3 cell line resulted in decreased in vivo and in vitro growth potential together with decreased cell invasiveness and ability to adhere to extracellular matrix, and enhanced paxillin staining. This further highlights the importance of EPLIN in regulating prostate cancer cell growth and aggressiveness, and suggests a possible connection between EPLIN and paxillin.

SIPA1 Is a Modulator of HGF/MET Induced Tumour Metastasis via the Regulation of Tight Junction-Based Cell to Cell Barrier Function.

BACKGROUND: Lung cancer is the leading cause of cancer death. SIPA1 is a mitogen induced GTPase activating protein (GAP) and may hamper cell cycle progression. SIPA1 has been shown to be involved in MET signaling and may contribute to tight junction (TJ) function and cancer metastasis. METHODS: Human lung tumour cohorts were analyzed. In vitro cell function assays were performed after knock down of SIPA1 in lung cancer cells with/without treatment. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to analyze expression of HGF (hepatocyte growth factor), MET, and their downstream markers. Immunohistochemistry (IHC) and immunofluorescence (IFC) staining were performed. RESULTS: Higher expression of SIPA1 in lung tumours was associated with a poorer prognosis. Knockdown of SIPA1 decreased invasiveness and proliferation of in vitro cell lines, and the SIPA1 knockdown cells demonstrated leaky barriers. Knockdown of SIPA1 decreased tight junction-based barrier function by downregulating MET at the protein but not the transcript level, through silencing of Grb2, SOCS, and PKCµ (Protein kinase Cµ), reducing the internalization and recycling of MET. Elevated levels of SIPA1 protein are correlated with receptor tyrosine kinases (RTKs), especially HGF/MET and TJs. The regulation of HGF on barrier function and invasion required the presence of SIPA1. CONCLUSIONS: SIPA1 plays an essential role in lung tumourigenesis and metastasis. SIPA1 may be a diagnostic and prognostic predictive biomarker. SIPA1 may also be a potential therapeutic target for non-small cell lung cancer (NSCLC) patients with aberrant MET expression and drug resistance.

Location, function and role of stromal cell­derived factors and possible implications in cancer (Review).

Despite improvements in therapy and management, cancer represents and remains a major cause of mortality and morbidity worldwide. Although genetics serve an important role in tumorigenesis and tumour progression, the tumour microenvironment (TME) in solid tumours is also important and has been indicated to contribute to these processes. Stromal cell­derived factors (SDFs) represent an important family within the TME. The family includes SDF­1, SDF­2, SDF2­like 1 (SDF2L1), SDF­3, SDF­4 and SDF­5. SDF­1 has been demonstrated to act as a positive regulator in a number of types of tumour, such as oesophago­gastric, pancreatic, lung, breast, colorectal and ovarian cancer, while the biology and functions of other members of the SDF family, including SDF­2, SDF2L1, SDF­4 and SDF­5, in cancer are different, complex and controversial, and remain mainly unknown. Full identification and understanding of the SDFs across multiple types of cancer is required to elucidate their function and establish potential key targets in cancer.

NUPR1 and its potential role in cancer and pathological conditions (Review).

Nuclear protein­1 (NUPR1) is also known as Com­1 or p8. It is a protein primarily found in the nucleus of various cells, including cancer cells, and it has been found to play an important role in cell stress and stress­related apoptosis. Over the past two decades, NUPR1 has been firmly indicated to play a role in the development and progression of numerous types of cancer, as well as in a number of other pathological conditions, including pancreatitis, diabetes, neurological and inflammatory conditions. The past decade has witnessed a rapid understanding of the biological and cellular mechanisms through which NUPR1 operates on cells and the identification of new variant of the protein. Most importantly, there have been comprehensive studies on the clinical and pathological aspects of NUPR1 and its variant in multiple malignancies and identification of therapeutic methods by targeting the protein. The present review aimed to summarise the current knowledge relating to NUPR1 in human malignancies and to discuss the associated controversies and potential future prospects of this molecule.

SIKs suppress tumor function and regulate drug resistance in breast cancer.

Salt-inducible kinases (SIKs), belonging to an AMP-activated kinase (AMPK) family, have an evolving role in tumourigenesis and metastasis in many solid tumours. However, the function of SIKs in breast cancer is not fully established. Here, we systematically elucidated the function of SIK family members in breast cancer. In clinical cohort of breast cancer, the expression of SIK1, SIK2 and SIK3 increased expression of SIKs was associated with good clinical outcome in breast cancer cohort. In vitro, reduced expression of SIK2 and SIK3, by way of knockdown increased the proliferation of breast cancer cells. However, SIK2 and SIK3 had contrasting effects on adhesion in breast cancer cells. Knockdown of SIK2 only enhanced the adhesion of triple negative breast cancer cell, while knockdown of SIK3 can decrease the adhesion of both MDA-MB-231 and MCF-7 cells. Interestingly, knockdown of SIK1 and SIK3 was seen to increase the invasion of MDA-MB-231 cells. Furthermore, reduced SIKs, even triple knockdown of SIK1, SIK2 and SIK3 rendered the breast cancer cells to confer chemoresistance to paclitaxel and cisplatin. Collectively, the study reports that SIKs are actively involved in regulating the aggressive functions of breast cancer cells and influence the clinical course of the patients with breast cancer that they molecules are potential prognostic factors and chemotherapy biomarkers.