The challenge of pancreatic cancer therapy and novel treatment strategy using engineered mesenchymal stem cells

Extracellular Regucalcin: A Potent Suppressor in the Cancer Cell Microenvironment

The regucalcin gene is located on the X chromosome, comprising seven exons and six introns. This gene and protein are expressed in various tissues and cells and is predominantly expressed in human liver, kidney, and adrenal tissues. Regucalcin gene expression is enhanced via a mechanism mediated by several signaling molecules and transcription factors. Regucalcin plays a multifunctional role in cellular regulation in maintaining cell homeostasis. In addition, regucalcin has been implicated in several metabolic disorders and diseases. In particular, regucalcin plays a role as a novel suppressor in several types of cancer patients. Increased expression of regucalcin suppresses the growth of human cancer cells, suggesting its pivotal role in suppressing tumor development. The survival time of cancer patients is prolonged with increased expression of regucalcin in the tumor tissues. The adhesion, migration, invasion, and bone metastatic activity of cancer cells are blocked by the overexpression of regucalcin, promoting dormancy in cancer patients. Interestingly, regucalcin is also found in human serum, suggesting its character as a novel biomarker in various diseases. This extracellular regucalcin has been shown to suppress human cancer cells' growth and bone metastatic activity. Thus, extracellular regucalcin may play a vital role as a suppressor of human cancer activity. Alteration of the serum regucalcin levels in physiological and pathophysiological conditions may influence the activity of cancer cells in the microenvironment. This review will discuss the potential role of extracellular regucalcin in cancer cell activity as a critical suppressor in the cancer microenvironment.

Nanotechnology and bioengineering approaches to improve the potency of mesenchymal stem cell as an off-the-shelf versatile tumor delivery vehicle

Targeting actionable mutations in oncogene-driven cancers and the evolution of immuno-oncology are the two prominent revolutions that have influenced cancer treatment paradigms and caused the emergence of precision oncology. However, intertumoral and intratumoral heterogeneity are the main challenges in both fields of precision cancer treatment. In other words, finding a universal marker or pathway in patients suffering from a particular type of cancer is challenging. Therefore, targeting a single hallmark or pathway with a single targeted therapeutic will not be efficient for fighting against tumor heterogeneity. Mesenchymal stem cells (MSCs) possess favorable characteristics for cellular therapy, including their hypoimmune nature, inherent tumor-tropism property, straightforward isolation, and multilineage differentiation potential. MSCs can be loaded with various chemotherapeutics and oncolytic viruses. The combination of these intrinsic features with the possibility of genetic manipulation makes them a versatile tumor delivery vehicle that can be used for in vivo selective tumor delivery of various chemotherapeutic and biological therapeutics. MSCs can be used as biofactory for the local production of chemical or biological anticancer agents at the tumor site. MSC-mediated immunotherapy could facilitate the sustained release of immunotherapeutic agents specifically at the tumor site, and allow for the achievement of therapeutic concentrations without the need for repetitive systemic administration of high therapeutic doses. Despite the enthusiasm evoked by preclinical studies that used MSC in various cancer therapy approaches, the translation of MSCs into clinical applications has faced serious challenges. This manuscript, with a critical viewpoint, reviewed the preclinical and clinical studies that have evaluated MSCs as a selective tumor delivery tool in various cancer therapy approaches, including gene therapy, immunotherapy, and chemotherapy. Then, the novel nanotechnology and bioengineering approaches that can improve the potency of MSC for tumor targeting and overcoming challenges related to their low localization at the tumor sites are discussed.

Regucalcin Is a Potential Regulator in Human Cancer: Aiming to Expand into Cancer Therapy

Regucalcin, a calcium-binding protein lacking the EF-hand motif, was initially discovered in 1978. Its name is indicative of its function in calcium signaling regulation. The rgn gene encodes for regucalcin and is situated on the X chromosome in both humans and vertebrates. Regucalcin regulates pivotal enzymes involved in signal transduction and has an inhibitory function, which includes protein kinases, protein phosphatases, cysteinyl protease, nitric oxide dynthetase, aminoacyl-transfer ribonucleic acid (tRNA) synthetase, and protein synthesis. This cytoplasmic protein is transported to the nucleus where it regulates deoxyribonucleic acid and RNA synthesis as well as gene expression. Overexpression of regucalcin inhibits proliferation in both normal and cancer cells in vitro, independent of apoptosis. During liver regeneration in vivo, endogenous regucalcin suppresses cell growth when overexpressed. Regucalcin mRNA and protein expressions are significantly downregulated in tumor tissues of patients with various types of cancers. Patients exhibiting upregulated regucalcin in tumor tissue have shown prolonged survival. The decrease of regucalcin expression is linked to the advancement of cancer. Overexpression of regucalcin carries the potential for preventing and treating carcinogenesis. Additionally, extracellular regucalcin has displayed control over various types of human cancer cells. Regucalcin may hold a prominent role as a regulatory factor in cancer development. Supplying the regucalcin gene could prove to be a valuable asset in cancer treatment. The therapeutic value of regucalcin suggests its potential significance in treating cancer patients. This review delves into the most recent research on the regulatory role of regucalcin in human cancer development, providing a novel approach for treatment.

Drug Delivery Strategies for the Treatment of Pancreatic Cancer

Pancreatic cancer is fast becoming a global menace and it is projected to be the second leading cause of cancer-related death by 2030. Pancreatic adenocarcinomas, which develop in the pancreas' exocrine region, are the predominant type of pancreatic cancer, representing about 95% of total pancreatic tumors. The malignancy progresses asymptomatically, making early diagnosis difficult. It is characterized by excessive production of fibrotic stroma known as desmoplasia, which aids tumor growth and metastatic spread by remodeling the extracellular matrix and releasing tumor growth factors. For decades, immense efforts have been harnessed toward developing more effective drug delivery systems for pancreatic cancer treatment leveraging nanotechnology, immunotherapy, drug conjugates, and combinations of these approaches. However, despite the reported preclinical success of these approaches, no substantial progress has been made clinically and the prognosis for pancreatic cancer is worsening. This review provides insights into challenges associated with the delivery of therapeutics for pancreatic cancer treatment and discusses drug delivery strategies to minimize adverse effects associated with current chemotherapy options and to improve the efficiency of drug treatment.

Mesenchymal Stromal Cell-Based Targeted Therapy Pancreatic Cancer: Progress and Challenges

Pancreatic cancer is an aggressive malignancy with high mortality rates and poor prognoses. Despite rapid progress in the diagnosis and treatment of pancreatic cancer, the efficacy of current therapeutic strategies remains limited. Hence, better alternative therapeutic options for treating pancreatic cancer need to be urgently explored. Mesenchymal stromal cells (MSCs) have recently received much attention as a potential therapy for pancreatic cancer owing to their tumor-homing properties. However, the specific antitumor effect of MSCs is still controversial. To this end, we aimed to focus on the potential anti-cancer treatment prospects of the MSC-based approach and summarize current challenges in the clinical application of MSCs to treat pancreatic cancer.

Nanomedicine for overcoming therapeutic and diagnostic challenges associated with pancreatic cancer

Pancreatic cancer is the second leading cause of cancer-related death in the USA. The 5-year survival rate for pancreatic cancer is as low as 10%, making it one of the most deadly cancers. This dismal prognosis is caused, in part, by the lack of early detection and screening options, leading to late-stage detection of the disease, at a point at which chemotherapy is no longer effective. However, nanoparticle (NP) drug delivery systems have increased the efficacy of chemotherapeutics by improving the targeting ability of drugs to the tumor site, while also decreasing the risk of local and systemic toxicity. Such efforts can contribute to the development of early diagnosis and routine screening tests, which will drastically improve the survival rates and prognosis of patients with pancreatic cancer.

Long Non-Coding RNA Differentiation Antagonizing Nonprotein Coding RNA (DANCR) Promotes Proliferation and Invasion of Pancreatic Cancer by Sponging miR-214-5p to Regulate E2F2 Expression

Background

Long non-coding RNA differentiation antagonizing nonprotein coding RNA (lncRNA DANCR) has been reported to act as an oncogene in various human cancers. The role of DANCR in development of pancreatic cancer (PC) is unknown. The aim of our research was to investigate the biological role of DANCR in PC.

Material/Methods

Expressions of DANCR, miR-214-5p, and E2F2 mRNA in PC tissues and cell lines were examined by qRT-PCR. Western blotting was carried out for detection of E2F2 protein expression in PC cells. Transwell assays were used to examine the metastatic ability of PC cells, while CCK-8 and colony formation assay were applied to evaluate cell proliferation. The effects of DANCR on PC cells were assessed by knockdown in vitro and in vivo. The regulatory mechanism of competitive endogenous RNAs were obtained from bioinformatics prediction and luciferase reporter assay.

Results

DANCR was markedly upregulated in clinical tissues and cell lines of PC. High DANCR expression exhibited a significant correlation with poor prognosis. DANCR knockdown inhibited growth and metastasis of PC cells. Furthermore, DANCR acted as sponge to regulate miR-214-5p, and miR-214-5p inhibitor reversed the effects of DANCR knockdown on PC cells. Moreover, DANCR positively modulated E2F2 expression through miR-214-5p in PC cells.

Conclusions

Collectively, our findings demonstrated that lncRNA DANCR/miR-214-5p/E2F2 axis acts as an oncogene in PC development, which might provide a potential target for PC therapy.

Mesenchymal Stem Cells as New Therapeutic Approach for Diabetes and Pancreatic Disorders

Diabetes is a worldwide disease which actually includes different disorders related to glucose metabolism. According to different epidemiological studies, patients affected by diabetes present a higher risk to develop both acute and chronic pancreatitis, clinical situations which, in turn, increase the risk to develop pancreatic cancer. Current therapies are able to adjust insulin levels according to blood glucose peak, but they only partly reach the goal to abrogate the consequent inflammatory milieu responsible for diabetes-related diseases. In recent years, many studies have investigated the possible use of adult mesenchymal stem cells (MSCs) as alternative therapeutic treatment for diabetes, with promising results due to the manifold properties of these cells. In this review we will critically analyze the many different uses of MSCs for both diabetes treatment and for the reduction of diabetes-related disease development, focusing on their putative molecular mechanisms.

Long noncoding RNA SNHG1 promotes cell proliferation through PI3K/AKT signaling pathway in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most common causes of cancer-related death. Recently, long noncoding RNAs (lncRNAs) have emerged as significant regulators in numerous cancers, including PDAC. LncRNA small nucleolar RNA host gene 1 (SNHG1) has been reported in the development of several tumors, but the biological roles of it in PDAC remain to be illuminated. This study aims to investigate the function of lncRNA SNHG1, revealing its molecular mechanism and clinical significance in PDAC. Herein, we found that SNHG1 was highly expressed in PDAC tissues in comparison with adjacent noncancerous tissues, being closely related to tumor size and TNM stage. Functionally, silencing of SNHG1 could significantly inhibit cell proliferation, promote cell apoptosis, as well as alter cell cycle progression, whereas the contrary results could be presented in the overexpression of SNHG1. In addition, in vivo xenograft experiment also further confirmed the above results. Finally, an activator (740Y-P) and inhibitor (LY294002) of the PI3K/AKT signaling pathway were used in the western blot assays and the following rescue experiments, demonstrating that SNHG1 facilitates cell proliferation and tumorigenicity partly via the PI3K/AKT signaling pathway in PDAC. Hence, SNHG1 may be a prospective therapeutic target.

The Role of Wnt Signal in Glioblastoma Development and Progression: A Possible New Pharmacological Target for the Therapy of This Tumor

Wnt is a complex signaling pathway involved in the regulation of crucial biological functions such as development, proliferation, differentiation and migration of cells, mainly stem cells, which are virtually present in all embryonic and adult tissues. Conversely, dysregulation of Wnt signal is implicated in development/progression/invasiveness of different kinds of tumors, wherein a certain number of multipotent cells, namely “cancer stem cells”, are characterized by high self-renewal and aggressiveness. Hence, the pharmacological modulation of Wnt pathway could be of particular interest, especially in tumors for which the current standard therapy results to be unsuccessful. This might be the case of glioblastoma multiforme (GBM), one of the most lethal, aggressive and recurrent brain cancers, probably due to the presence of highly malignant GBM stem cells (GSCs) as well as to a dysregulation of Wnt system. By examining the most recent literature, here we point out several factors in the Wnt pathway that are altered in human GBM and derived GSCs, as well as new molecular strategies or experimental drugs able to modulate/inhibit aberrant Wnt signal. Altogether, these aspects serve to emphasize the existence of alternative pharmacological targets that may be useful to develop novel therapies for GBM.

Pretreatment blood neutrophil/lymphocyte ratio is associated with metastasis and predicts survival in patients with pancreatic cancer

BACKGROUND

The predictive value of systemic inflammatory markers has been explored in various types of cancer. In the present study, we aimed to investigate the association between pretreatment neutrophil/lymphocyte ratio (NLR) and tumor metastasis in pancreatic cancer, and the values of NLR as a prognostic factor of overall survival.

METHODS

Clinical and laboratory data from 256 consecutive pancreatic cancer patients were analyzed retrospectively. The NLR was recorded before treatment and analyzed along with clinicopathological characteristics and overall survival of pancreatic cancer patients.

RESULTS

Multivariate analysis revealed that pretreatment NLR (HR: 2.393; 95% CI: 1.326-4.320; P=0.004) was an independent risk factor for distant metastasis. Furthermore, COX regression analysis showed that in addition to pretreatment NLR (HR: 1.871; 95% CI: 1.413-2.477; P<0.001), metastasis and stage were independent prognostic factors.

CONCLUSION

Pretreatment NLR values were significantly associated with distant metastasis in pancreatic cancer patients. Higher NLR values were detected in metastatic disease and may be an independent prognostic factor of overall survival in pancreatic cancer patients.

Methods and practices to diversify cell-based products

Medicinal signaling cell (MSC)-based products represent emerging treatments in various therapeutic areas including cardiometabolic, inflammation, autoimmunity, orthopedics, wound healing and oncology. Exploring innovation beyond minimally manipulated plastic-adherent ex vivo expanded allogeneic MSCs enables product delineation. Product delineation is on the critical path to maximize clinical benefits and market access. An innovation framework is presented here along various innovation dimensions comprising composition-of-matter by means of positive cell surface markers, formulation varying for example the cell dose or the preservation mode and medium, manufacturing to adapt the secretome of MSCs to the condition of interest, the mode of delivery and corresponding delivery devices, as well as molecular engineering and biomarkers. The rationale of the innovation space thus described applies generally to all cell-based therapies.

Secretion of interleukin-6 by bone marrow mesenchymal stem cells promotes metastasis in hepatocellular carcinoma

Mesenchymal stem cells (MSCs) interact with tumor cells and regulate tumorigenesis and metastasis. As one of the important components of the tumor microenvironment, MSC-secreted cytokines play a critical role in cancer development. However, whether and how bone marrow MSCs (BMSCs) and their secreted cytokines participate in hepatocellular carcinoma (HCC) progression, still remains largely unknown. In the present study, we first measured the concentration of interleukin-6 (IL-6) in BMSC conditioned medium (BMSC-CM). Next, we assessed the changes of invasion ability in response to treatment of BMSC-CM or recombinant IL-6 in two human HCC cell lines Bel-7404 and HepG2. Then we analyzed the level of key components of the IL-6 signal pathway, including IL-6 receptor and signal transducer (i.e. IL-6R and gp130), a transcription factor STAT3 (signal transducer and activator of transcription 3), as well as its target genes BCL2, CCND1, MCL1 and MMP2, in BMSC-CM or recombinant IL-6 treated Bel-7404 and HepG2 cells. Results showed that a considerable amount of IL-6 was secreted by BMSCs, and BMSC-CM markedly elevated Bel-7404 cell invasion rate and stimulated the signal transduction of IL-6/STAT3 pathway. Neutralizing the secreted IL-6 bioactivity by the anti-IL-6 antibody diminished the invasion-promoting effect and down-regulated IL-6/STAT3 pathway of BMSC-CM treated Bel-7404 cells. In conclusion, we found that BMSCs may activate the IL-6/STAT3 signaling pathway and promote cell invasion in Bel-7404 cells, suggesting that this protumor effect should be seriously considered before clinical application of MSC-mediated cancer therapy.

Clinical data combined with radiological imaging improves the accuracy of TNM staging of pancreatic body and tail adenocarcinoma

PURPOSE

Pancreatic body and tail adenocarcinoma (PBTA) remains one of the deadliest cancers, and current radiological modalities still have limitations on the staging of PBTA. Improving PBTA staging will contribute to the management of this disease.

PATIENTS AND METHODS

Clinicopathological characteristics of 91 surgically treated PBTA patients were retrospectively retrieved. Clinical data associated with postoperative tumor staging (pTNM) were assessed using ordinal logistic regression model. Discriminant analysis was performed using function formula based on multivariate analysis results; further cross-validation was conducted by Bootstrap methods.

RESULTS

Multivariate analysis showed that carbohydrate antigen 19-9 ≥955.0 U/L, albumin, and alkaline phosphatase/total bilirubin ratio were independent factors contributing to improved accuracy of pTNM staging. Discriminant analysis exhibited better performance and showed that the probability of accurate prediction of pTNM stage was 90.6% and the probability of cross-validation was 85.9%. After excluding patients with preoperative diagnosis of stage IV disease, the probability of accurate prediction of pTNM stage was 86.1% and the probability of cross-validation was 75.0%.

CONCLUSION

The combination of imaging and clinical data has higher accuracy in staging PBTA than radiological data alone. A model proposed in this study will improve the management of PBTA.

ROR functions as a ceRNA to regulate Nanog expression by sponging miR-145 and predicts poor prognosis in pancreatic cancer

lncRNAs have emerged as key regulators of tumor development and progression. ROR is a typical lncRNA that plays important regulatory roles in the pathogenesis and progression of tumors. Nevertheless, current understanding of the involvement of ROR in pancreatic adenocarcinoma tumorigenesis remains limited. In this study, we measured ROR in 61 paired cancerous and noncancerous tissue samples by qRT-PCR and investigated the biological role of ROR on the phenotypes of pancreatic cancer stem cells (PCSCs) in vitro and in vivo. The effects of ROR on PCSCs were studied by RNA interference approaches in vitro and in vivo. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation. The positive ROR/Nanog interaction was identified and verified by immunohistochemistry assay. Compared with adjacent non-tumor tissues, ROR was up-regulated in most tumor tissues. Knockdown of ROR by RNA interference in PCSCs inhibited proliferation, induced apoptosis and decreased migration. Moreover, ROR silencing resulted in significantly decreased tumourigenicity of PCSCs in nude mice than controls. In particular, ROR may act as a ceRNA, effectively becoming a sink for miR-145, thereby activating the derepression of core transcription factors Nanog. In conclusions, we demonstrated that decreased ROR expression could inhibit cell proliferation, invasion, and tumourigenicity by modulating Nanog. Therefore, ROR is a potential novel prognostic marker to predict the clinical outcome of pancreatic cancer patients after surgery and may be a rational target for therapy.

Perichondrium mesenchymal stem cells inhibit the growth of breast cancer cells via the DKK-1/Wnt/β-catenin signaling pathway

In recent years, mesenchymal stem cells (MSCs), which possess the ability to specifically home to tumor sites, with the potential of multi-directional differentiation and low immunogenicity, have been reported to inhibit the growth of various types of tumors. In the present study, we isolated MSCs from the rib perichondrium (PMSCs). By comparing PMSCs with bone marrow‑derived mesenchymal stem cells (BMSCs), we demonstrated that PMSCs present biological characteristics similar to those of BMSCs. Furthermore, we explored the effect and antitumor mechanism of PMSCs in rat SHZ-88 breast cancer cells. The growth, migration and invasion of the SHZ-88 cells were significantly inhibited, and the Wnt/β-catenin pathway and its target genes were downregulated in the SHZ-88 cells by PMSC-conditioned medium. The expression level of dickkopf-1 (DKK-1) was higher in the PMSCs than that noted in the SHZ-88 cells. Neutralization of DKK-1 in the PMSC‑conditioned medium attenuated the inhibitory effects of PMSCs on SHZ-88 cells. Therefore, PMSC-secreted DKK-1 is involved in the inhibition of SHZ-88 cell growth, migration and invasion, via the Wnt/β‑catenin signaling pathway. In addition, we demonstrated that PMSCs inhibited the growth of breast cancer in vivo and prolonged the survival time of tumor‑bearing rats. PMSCs inhibited the growth of transplanted breast tumors through the Wnt/β-catenin signaling pathway. In conclusion, our data confirmed that MSCs derived from the perichondrium present biological characteristics similar to those of BMSCs and inhibit the growth of breast cancer cells through the Wnt/β-catenin signaling pathway in vitro and in vivo. DKK-1 secreted by PMSCs played a vital role in controlling the Wnt/β-catenin signaling pathway in breast cancer.

Prolonged survival in pancreatic cancer patients with increased regucalcin gene expression: Overexpression of regucalcin suppresses the proliferation in human pancreatic cancer MIA PaCa-2 cells in vitro

Approximately 90% of all pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is a highly aggressive malignancy and is one of the deadliest. This poor clinical outcome is due to the prominent resistance of pancreatic cancer to drug and radiation therapies. Regucalcin plays a pivotal role as a suppressor protein in signal transduction in various types of cells including tumor tissues. We demonstrated that the prolonged survival is induced in PDAC patients with increased regucalcin gene expression using a dataset of PDAC obtained from GEO database (GSE17891) together with the clinical annotation data file. Moreover, overexpression of regucalcin with full length was demonstrated to suppress the proliferation, cell death and migration in human pancreatic cancer MIA PaCa-2 (K-ras mutated) cells that possess resistance to drug and radiation therapies. Suppressive effects of regucalcin on cell proliferation and death were not seen in the cells overexpressed with regucalcin cDNA alternatively spliced variants (deleted exon 4 or deleted exon 4 and 5). Regucalcin was suggested to induce G1 and G2/M phase cell cycle arrest in MIA PaCa-2 cells. Suppressive effects of regucalcin on cell proliferation were independent of cell death. Overexpression of regucalcin was found to suppress signaling pathways including Akt, MAP kinase and SAPK/JNK, to increase the protein levels of p53, a tumor suppresser, and to decrease K-ras, c-fos and c-jun, a oncogene, by suppressing signaling pathways that are related to signaling of K-ras. Regucalcin may play a potential role as a suppressor protein in human pancreatic cancer.

Viro-immune therapy: A new strategy for treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an almost uniformly lethal disease with less than 5% survival at five years. This is largely due to metastatic disease, which is already present in the majority of patients when diagnosed. Even when the primary cancer can be removed by radical surgery, local recurrence occurs within one year in 50%-80% of cases. Therefore, it is imperative to develop new approaches for the treatment of advanced cancer and the prevention of recurrence after surgery. Tumour-targeted oncolytic viruses (TOVs) have become an attractive therapeutic agent as TOVs can kill cancer cells through multiple mechanisms of action, especially via virus-induced engagement of the immune response specifically against tumour cells. To attack tumour cells effectively, tumour-specific T cells need to overcome negative regulatory signals that suppress their activation or that induce tolerance programmes such as anergy or exhaustion in the tumour microenvironment. In this regard, the recent breakthrough in immunotherapy achieved with immune checkpoint blockade agents, such as anti-cytotoxic T-lymphocyte-associate protein 4, programmed death 1 (PD-1) or PD-L1 antibodies, has demonstrated the possibility of relieving immune suppression in PDAC. Therefore, the combination of oncolytic virotherapy and immune checkpoint blockade agents may synergistically function to enhance the antitumour response, lending the opportunity to be the future for treatment of pancreatic cancer.

Emerging roles of microRNAs in pancreatic cancer diagnosis, therapy and prognosis (Review)

Pancreatic cancer is one of the leading causes of cancer related death. Increasing incidence and mortality indicates a lack of detection and post diagnostic management of this disease. Recent evidences suggest that, miRNAs are very attractive target molecules that can serve as biomarkers for predicting development and progression of pancreatic cancer. Furthermore, miRNAs are also promising therapeutic targets for pancreatic cancer. The objective of the present review is to discuss the significance of miRNA in pancreatic cancer development, diagnosis, therapy and prognosis. We extracted and compiled the useful information from PubMed database, which satisfied our criteria for analysis of miRNAs in pancreatic cancer diagnosis, therapy and prognosis. A summary of the most important miRNAs known to regulate pancreatic tumorigenesis is provided. The review also provides a collection of evidence that show miRNA profiles of biofluids hold much promise for use as biomarkers to predict and detect development of pancreatic cancer in its early stages. Identification of key miRNA networks in pancreatic cancer will provide long-awaited diagnostic/therapeutic/prognostic tools for early detection, better treatment options, and extended life expectancy and quality of life in PDAC patients.

New targeted therapies in pancreatic cancer

Patients with pancreatic cancer have a poor prognosis with a median survival of 4-6 mo and a 5-year survival of less than 5%. Despite therapy with gemcitabine, patient survival does not exceed 6 mo, likely due to natural resistance to gemcitabine. Therefore, it is hoped that more favorable results can be obtained by using guided immunotherapy against molecular targets. This review summarizes the new leading targeted therapies in pancreatic cancers, focusing on passive and specific immunotherapies. Passive immunotherapy may have a role for treatment in combination with radiochemotherapy, which otherwise destroys the immune system along with tumor cells. It includes mainly therapies targeting against kinases, including epidermal growth factor receptor, Ras/Raf/mitogen-activated protein kinase cascade, human epidermal growth factor receptor 2, insulin growth factor-1 receptor, phosphoinositide 3-kinase/Akt/mTOR and hepatocyte growth factor receptor. Therapies against DNA repair genes, histone deacetylases, microRNA, and pancreatic tumor tissue stromal elements (stromal extracellular matric and stromal pathways) are also discussed. Specific immunotherapies, such as vaccines (whole cell recombinant, peptide, and dendritic cell vaccines), adoptive cell therapy and immunotherapy targeting tumor stem cells, have the role of activating antitumor immune responses. In the future, treatments will likely include personalized medicine, tailored for numerous molecular therapeutic targets of multiple pathogenetic pathways.

Paracrine factors from adipose-mesenchymal stem cells enhance metastatic capacity through Wnt signaling pathway in a colon cancer cell co-culture model

Background

Mesenchymal stem cells (MSCs) in tumors have emerged as progenitors involved in stroma formation and metastasis of cancers, partially owing to their abilities to differentially express paracrine factors related to the proliferation and invasion of cancer cells. In this regard, increasing evidence has shown that MSCs have impacts on the malignancy of colon cancer, however, the underpinning mechanisms by which MSCs promote cancer metastasis remain elusive.

Methods

To investigate the crosstalk between adipose-derived MSCs (AMSCs) isolated from adipose tissues and colon cancer cells, a co-culture transwell model of AMSCs and colon cancer cells was employed, and the activation of Wnt signaling and paracrine factors in colon cancer cells and AMSCs were measured.

Results

The results showed that AMSCs could enhance the metastatic capacity of colon cancer cells with an elevated expression of mesenchymal-epithelial transition (EMT)-associated genes in a contact-dependent manner. Reciprocally, colon cancer cells were able to induce AMSCs to produce metastasis-related factors and cytokines, such as FGF10, VEGFC and matrix metalloproteinases (MMPs) in part through a mechanism of an activation of Wnt signaling, by which these factors in turn activate Wnt signaling of colon cancer cells. Intriguingly, an inhibition of Wnt signaling leads a reduced capacity of invasion and colony formation of colon cancer cells in vitro, and the tumorigenicity of cancer cells in a murine model.

Conclusions

These findings thus suggest that the crosstalk between the Wnt signaling of cancer cells and paracrine factors of AMSCs has an implication in colon cancer malignancy. This study thus uncovers a novel Wnt-paracrine factors mediated-crosstalk between colon cancer cells and AMSCs in cancer malignancy.

cDNA microarray analysis of the effect of cantharidin on DNA damage, cell cycle and apoptosis-associated gene expression in NCI-H460 human lung cancer cells in vitro

Cantharidin (CTD) induces cytotoxic effects in different types of human cancer cell; however, to date, there have been no studies on the effects of CTD on gene expression in human lung cancer cells and the potential associated signaling pathways. Therefore, the present study aimed to investigate how CTD affects the expression of key genes and functional pathways of human H460 lung cancer cells using complementary DNA microarray analysis. Human H460 lung cancer cells were cultured for 24 h in the presence or absence of 10 µM CTD; gene expression was then examined using microarray analysis. The results indicated that 8 genes were upregulated > 4-fold, 29 genes were upregulated >3-4-fold and 156 genes were upregulated >2-3-fold. In addition, 1 gene was downregulated >4 fold, 14 genes were downregulated >3-4-fold and 150 genes were downregulated >2-3 fold in H460 cells following exposure to CTD. It was found that CTD affected DNA damage genes, including DNIT3 and GADD45A, which were upregulated 2.26- and 2.60-fold, respectively, as well as DdiT4, which was downregulated 3.14-fold. In addition, the expression of genes associated with the cell cycle progression were altered, including CCND2, CDKL3 and RASA4, which were upregulated 2.72-, 2.19- and 2.72-fold, respectively; however, CDC42EP3 was downregulated 2.16-fold. Furthermore, apoptosis-associated genes were differentially expressed, including CARD6, which was upregulated 3.54-fold. In conclusion, the present study demonstrated that CTD affected the expression of genes associated with DNA damage, cell cycle progression and apoptotic cell death in human lung cancer H460 cells.

Development and Challenges of Nanovectors in Gene Therapy

In recent years, hundreds of genes have been linked to a variety of human diseases, and the field of gene therapy has emerged as a way to treat this wide range of diseases. The main goal of gene therapy is to find a gene delivery vehicle that can successfully target diseased cells and deliver therapeutic genes directly to their cellular compartment. The two main types of gene delivery vectors currently being investigated in clinical trials are recombinant viral vectors and synthetic nonviral vectors. Recombinant viral vectors take advantage of the evolutionarily optimized viral mechanisms to deliver genes, but they can be hard to specifically target in vivo and are also associated with serious side effects. Synthetic nonviral vectors are made out of highly biocompatible lipids or polymers, but they are much less efficient at delivering their genetic payload due to the lack of any active delivery mechanism. This mini review will introduce the current state of gene delivery in clinical trials, and discuss the specific challenges associated with each of these vectors. It will also highlight some specific gaps in knowledge that are limiting the advancement of this field and touch on the current areas of research being explored to overcome them.

A concise review on the current understanding of pancreatic cancer stem cells

Several evidences suggest that a small population of cells known as cancer stem cells (CSCs) or tumor initiating stemlike cells within a tumor is capable of tumor initiation, maintenance and propagation. Recent publications have supported the existence of CSCs in pancreatic tumors. The pancreatic stem/progenitor cells, which express self-renewal markers, are identified to be present in the peribiliary gland. Based on the CSC hypothesis, mutations can lead to the transformation of stem/progenitor cells or differentiated cells into CSCs. The pancreatic CSCs express a wide array of markers such as CD44, CD24, ESA, CD133, c-MET, CXCR4, PD2/Paf1 and ALDH1. The CSCs are isolated based on surface markers or by other methods such as ALDEFLOUR assay or Hoechst 33342 dye exclusion assay. The isolated cells are further characterized by in vitro and in vivo tumorigenic assays. The most important characteristics of CSCs are its ability to self-renew and impart drug resistance towards chemotherapy. Moreover, these distinct cells display alteration of signaling pathways pertaining to CSCs such as Notch, Wnt and Shh to maintain the self-renewal process. Failure of cancer treatment could be attributed to the therapy resistance exhibited by the CSCs. Metastasis and drug resistance in pancreatic cancer is associated with epithelial to mesenchymal transition (EMT). Furthermore, mucins, the high molecular weight proteins are found to be associated with pancreatic CSCs and EMT. Understanding the underlying molecular pathways that aid in the metastatic and drug resistant nature of these distinct cells will aid in targeting these cells. Overall, this review focuses on the various aspects of pancreatic adult/stem progenitors, CSC hypothesis, its markers, pathways, niche, EMT and novel therapeutic drugs used for the elimination of pancreatic CSCs.