Hypoxia-independent gene expression mediated by SOX9 promotes aggressive pancreatic tumor biology

CA9 and PRELID2; hypoxia-responsive potential therapeutic targets for pancreatic ductal adenocarcinoma as per bioinformatics analyses

A strong hypoxic environment has been observed in pancreatic ductal adenocarcinoma (PDAC) cells, which contributes to drug resistance, tumor progression, and metastasis. Therefore, we performed bioinformatics analyses to investigate potential targets for the treatment of PDAC. To identify potential genes as effective PDAC treatment targets, we selected all genes whose expression level was related to worse overall survival (OS) in The Cancer Genome Atlas (TCGA) database and selected only the genes that matched with the genes upregulated due to hypoxia in pancreatic cancer cells in the dataset obtained from the Gene Expression Omnibus (GEO) database. Although the extracted 107 hypoxia-responsive genes included the genes that were slightly enriched in angiogenic factors, TCGA data analysis revealed that the expression level of endothelial cell (EC) markers did not affect OS. Finally, we selected CA9 and PRELID2 as potential targets for PDAC treatment and elucidated that a CA9 inhibitor, U-104, suppressed pancreatic cancer cell growth more effectively than 5-fluorouracil (5-FU) and PRELID2 siRNA treatment suppressed the cell growth stronger than CA9 siRNA treatment. Thus, we elucidated that specific inhibition of PRELID2 as well as CA9, extracted via exhaustive bioinformatic analyses of clinical datasets, could be a more effective strategy for PDAC treatment.

Antiproliferative and apoptotic effects of telmisartan in human glioma cells

Glioblastoma is the most common primary central nervous system tumor in adults. Angiotensin II receptor blockers (ARBs) are broadly applied to treat hypertension. Moreover, research has revealed that ARBs have the capacity to suppress the growth of several cancer types. In this study, we assessed the effects of three ARBs with the ability to cross the blood brain barrier (telmisartan, valsartan and fimasartan) on cell proliferation in three glioblastoma multiforme (GBM) cell lines. Telmisartan markedly suppressed the proliferation, migration, and invasion of these three GBM cell lines. Microarray data analysis revealed that telmisartan regulates DNA replication, mismatch repair, and the cell cycle pathway in GBM cells. Furthermore, telmisartan induced G0/G1 phase arrest and apoptosis. The bioinformatic analysis and western blotting results provide evidence that SOX9 is a downstream target of telmisartan. Telmisartan also suppressed tumor growth in vivo in an orthotopic transplant mouse model. Therefore, telmisartan is a potential treatment for human GBM.

New insights into KLFs and SOXs in cancer pathogenesis, stemness, and therapy

Despite the development of cancer therapies, the success of most treatments has been impeded by drug resistance. The crucial role of tumor cell plasticity has emerged recently in cancer progression, cancer stemness and eventually drug resistance. Cell plasticity drives tumor cells to reversibly convert their cell identity, analogous to differentiation and dedifferentiation, to adapt to drug treatment. This phenotypical switch is driven by alteration of the transcriptome. Several pluripotent factors from the KLF and SOX families are closely associated with cancer pathogenesis and have been revealed to regulate tumor cell plasticity. In this review, we particularly summarize recent studies about KLF4, KLF5 and SOX factors in cancer development and evolution, focusing on their roles in cancer initiation, invasion, tumor hierarchy and heterogeneity, and lineage plasticity. In addition, we discuss the various regulation of these transcription factors and related cutting-edge drug development approaches that could be used to drug "undruggable" transcription factors, such as PROTAC and PPI targeting, for targeted cancer therapy. Advanced knowledge could pave the way for the development of novel drugs that target transcriptional regulation and could improve the outcome of cancer therapy.

Transformer 2 alpha homolog is a downstream gene of hypoxia-inducible factor 1 subunit alpha and is involved in the progression of pancreatic cancer

Intratumoral hypoxia is a common feature of pancreatic cancer (PC) and also plays a role in its progression. However, hypoxia-regulated signatures in PC are still not completely understood. This study aimed to identify core hypoxia-associated genes and determine their underlying molecular mechanisms in PC cells. Transformer 2 alpha homolog (TRA2A) was found to be an important hypoxia-associated gene, which was upregulated in PC tissues and in PC cells cultured under hypoxia. High TRA2A expression was associated with advanced stage, poor differentiation, and lymph node metastasis. Under normoxic and hypoxic conditions, knockdown of TRA2A both markedly suppressed PC cell proliferation and motility in vitro and in vivo, as well as activation of the AKT pathway. Hypoxia-inducible factor 1 subunit alpha (HIF1α) upregulated the transcription of TRA2A by directly binding to its promoter. TRA2A showed a co-expression relationship with HIF1α in PC tissues. Overexpression of TRA2A alleviated the pro-inhibitive functions of HIF1α-inhibition on PC cell proliferation and motility under hypoxia. In conclusion, TRA2A is a crucial downstream gene of HIF1α that accelerates the proliferation and motility of PC cells. TRA2A may be a novel and practical molecular target for investigating the hypoxic response of PC cells.Abbreviations: TRA2A, transformer 2A protein; PC, pancreatic cancer; HIF1α, hypoxia-inducible factor 1-alpha; GEO, Gene Expression Omnibus; IHC, immunohistochemical staining.

SOX9 Triggers Different Epithelial to Mesenchymal Transition States to Promote Pancreatic Cancer Progression

Simple Summary

Pancreatic cancers are lethal types of cancer. A majority of patients progress to an advanced and metastatic disease, which remains a major clinical problem. Therefore, it is crucial to identify critical regulators to help predict the disease progression and to develop more efficacious therapeutic approaches. In this work we found that an increased expression of the developmental factor SOX9 is associated with metastasis, a poor prognosis and resistance to therapy in pancreatic ductal adenocarcinoma patients and in cell cultures. We also found that this effect is at least in part due to the ability of SOX9 to regulate the activity of stem cell factors, such as BMI1, in addition to those involved in EMT and metastasis.

Abstract

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers mainly due to spatial obstacles to complete resection, early metastasis and therapy resistance. The molecular events accompanying PDAC progression remain poorly understood. SOX9 is required for maintaining the pancreatic ductal identity and it is involved in the initiation of pancreatic cancer. In addition, SOX9 is a transcription factor linked to stem cell activity and is commonly overexpressed in solid cancers. It cooperates with Snail/Slug to induce epithelial-mesenchymal transition (EMT) during neural development and in diseases such as organ fibrosis or different types of cancer. Methods: We investigated the roles of SOX9 in pancreatic tumor cell plasticity, metastatic dissemination and chemoresistance using pancreatic cancer cell lines as well as mouse embryo fibroblasts. In addition, we characterized the clinical relevance of SOX9 in pancreatic cancer using human biopsies. Results: Gain- and loss-of-function of SOX9 in PDAC cells revealed that high levels of SOX9 increased migration and invasion, and promoted EMT and metastatic dissemination, whilst SOX9 silencing resulted in metastasis inhibition, along with a phenotypic reversion to epithelial features and loss of stemness potential. In both contexts, EMT factors were not altered. Moreover, high levels of SOX9 promoted resistance to gemcitabine. In contrast, overexpression of SOX9 was sufficient to promote metastatic potential in K-Ras transformed MEFs, triggering EMT associated with Snail/Slug activity. In clinical samples, SOX9 expression was analyzed in 198 PDAC cases by immunohistochemistry and in 53 patient derived xenografts (PDXs). SOX9 was overexpressed in primary adenocarcinomas and particularly in metastases. Notably, SOX9 expression correlated with high vimentin and low E-cadherin expression. Conclusions: Our results indicate that SOX9 facilitates PDAC progression and metastasis by triggering stemness and EMT.

Exosome circCMTM3 promotes angiogenesis and tumorigenesis of hepatocellular carcinoma through miR-3619-5p/SOX9

AIM

As one of the most common and lethal carcinomas, hepatocellular carcinoma (HCC) is a global health concern and affects millions of people worldwide. Current treatments for HCC are very limited due to its unclear pathogenesis. Here, we aim to further investigate the role of circCMTM3/microRNA (miR)-3619-5p in HCC.

METHODS

Human blood samples were collected from HCC patients and healthy people. Quantitative reverse transcription-polymerase chain reaction and western blot analysis were undertaken to measure levels of circCMTM3, miR-3619-5p, SOX9, and exosome markers. The MTT, colony formation, and Transwell assays were used to examine the viability, migration, and invasion of human umbilical vein endothelial cells (HUVECs), respectively. Tube formation assay was used to assess angiogenesis. Dual luciferase assay was used to validate circCMTM3/miR-3619-5p and miR-3619-5p/SOX9 interactions. A nude mouse xenograft model was used to test the role of circCMTM3 in HCC in vivo.

RESULTS

Levels of circCMTM3 in exosomes from HCC patients and cells were elevated. Knockdown of circCMTM3 greatly decreased viability, migration, and invasion of HUVECs, as well as angiogenesis. CircCMTM3 acted as a miR-3619-5p sponge and miR-3619-5p inhibitor reversed the effects of si-circCMTM3 on angiogenesis. MiR-3619-5p directly targeted SOX9 and modulated angiogenesis through SOX9. Furthermore, knockdown of circCMTM3 suppressed angiogenesis and HCC tumor growth in vivo.

CONCLUSION

The exosome circCMTM3/miR-3619-5p/SOX9 axis from HCC cells promotes angiogenesis and thus contributes to HCC tumorigenesis.

The role of S100A9 in the interaction between pancreatic ductal adenocarcinoma cells and stromal cells

BACKGROUND

A major feature of the microenvironment in pancreatic ductal adenocarcinoma (PDAC) is the significant amount of extracellular matrix produced by pancreatic stellate cells (PSCs), which have been reported to enhance the invasiveness of pancreatic cancer cells and negatively impact the prognosis.

METHODS

We analyzed the data from two publicly available microarray datasets deposited in the Gene Expression Omnibus and found candidate genes that were differentially expressed in PDAC cells with metastatic potential and PDAC cells cocultured with PSCs. We studied the interaction between PDAC cells and PSCs in vitro and verified our finding with the survival data of patients with PDAC from the website of The Human Protein Atlas.

RESULTS

We found that PSCs stimulated PDAC cells to secrete S100A9, which attracted circulatory monocytes into cancer tissue and enhanced the expression of programmed death-ligand 1 (PD-L1) on macrophages. When analyzing the correlation of S100A9 and PD-L1 expression with the clinical outcomes of patients with PDAC, we ascertained that high expression of S100A9 and PD-L1 was associated with poor survival in patients with PDAC.

CONCLUSIONS

PSCs stimulated PDAC cells to secrete S100A9, which acts as a chemoattractant to attract circulatory monocytes into cancer microenvironment and induces expression of PD-L1 on macrophages. High expression of S100A9 and PD-L1 was associated with worse overall survival in a cohort of patients with PDAC.

Bioinformatic analysis linking genomic defects to chemosensitivity and mechanism of action

A joint analysis of the NCI60 small molecule screening data, their genetically defective genes, and mechanisms of action (MOA) of FDA approved cancer drugs screened in the NCI60 is proposed for identifying links between chemosensitivity, genomic defects and MOA. Self-Organizing-Maps (SOMs) are used to organize the chemosensitivity data. Student's t-tests are used to identify SOM clusters with enhanced chemosensitivity for tumor cell lines with versus without genetically defective genes. Fisher's exact and chi-square tests are used to reveal instances where defective gene to chemosensitivity associations have enriched MOAs. The results of this analysis find a relatively small set of defective genes, inclusive of ABL1, AXL, BRAF, CDC25A, CDKN2A, IGF1R, KRAS, MECOM, MMP1, MYC, NOTCH1, NRAS, PIK3CG, PTK2, RPTOR, SPTBN1, STAT2, TNKS and ZHX2, as possible candidates for roles in chemosensitivity for compound MOAs that target primarily, but not exclusively, kinases, nucleic acid synthesis, protein synthesis, apoptosis and tubulin. These results find exploitable instances of enhanced chemosensitivity of compound MOA's for selected defective genes. Collectively these findings will advance the interpretation of pre-clinical screening data as well as contribute towards the goals of cancer drug discovery, development decision making, and explanation of drug mechanisms.

SOX9: The master regulator of cell fate in breast cancer

SRY-related high-mobility group box 9 (SOX9) is an indispensable transcription factor that regulates multiple developmental pathways related to stemness, differentiation, and progenitor development. Previous studies have demonstrated that the SOX9 protein directs pathways involved in tumor initiation, proliferation, migration, chemoresistance, and stem cell maintenance, thereby regulating tumorigenesis as an oncogene. SOX9 overexpression is a frequent event in breast cancer (BC) subtypes. Of note, the molecular mechanisms and functional regulation underlying SOX9 upregulation during BC progression are still being uncovered. The focus of this review is to appraise recent advances regarding the involvement of SOX9 in BC pathogenesis. First, we provide a general overview of SOX9 structure and function, as well as its involvement in various kinds of cancer. Next, we discuss pathways of SOX9 regulation, particularly its miRNA-mediated regulation, in BC. Finally, we describe the involvement of SOX9 in BC pathogenesis via its regulation of pathways involved in regulating cancer hallmarks, as well as its clinical and therapeutic importance. In general, this review article aims to serve as an ample source of knowledge on the involvement of SOX9 in BC progression. Targeting SOX9 activity may improve therapeutic strategies to treat BC, but precisely inhibiting SOX9 using drugs and/or small peptides remains a huge challenge for forthcoming cancer research.

Effect of CXCL12 and Its Receptors on Unpredictable Renal Cell Carcinoma

Chemokines are chemotactic cytokines that participate in numerous cell functions during hematopoiesis, morphogenesis, inflammation, neovascularization, and autoimmune diseases and cancer. They achieve their functions on binding to their G protein-coupled receptors. CXCL12, or stromal cell-derived factor-1, is a homeostatic chemokine secreted by fibroblasts, macrophages, and endothelial cells. It binds to CXC receptor 4 (CXCR4), also known as fusin (CD184), and alternate CXC receptor 7 (CXCR7), also known as atypical chemokine receptor 3. The CXCL12/CXCR4 axis participates in homing of hematopoietic stem cells and the development and production of B and T lymphocytes, plasmacytoid dendritic cells, and natural killer cells. It has been examined in > 20 different malignancies. CXCL12 plays an important role in tumor metastasis because it mediates the migration of tumor cells through the endothelial vessel wall and extracellular matrix. Its expression has been highest in common metastatic sites such as the brain, bone marrow, lymph nodes, and liver. CXCR4 is expressed by tumor cells in prostate, breast, lung, and other malignancies. Numerous studies have shown its correlation with a poor prognosis, recurrence-free survival, and poor overall survival. The present review has addressed the structure and function of CXCL12 and its receptors and the effect CXCL12/CXCR4 axis has on the pathogenesis and clinical development of renal cell carcinoma, one of the most aggressive cancers in urology, with limited therapeutic options.

SOX9 Stem-Cell Factor: Clinical and Functional Relevance in Cancer

Transcriptional and epigenetic embryonic programs can be reactivated in cancer cells. As result, a specific subset of undifferentiated cells with stem-cells properties emerges and drives tumorigenesis. Recent findings have shown that ectoderm- and endoderm-derived tissues continue expressing stem-cells related transcription factors of the SOX-family of proteins such as SOX2 and SOX9 which have been implicated in the presence of cancer stem-like cells (CSCs) in tumors. Currently, there is enough evidence suggesting an oncogenic role for SOX9 in different types of human cancers. This review provides a summary of the current knowledge about the involvement of SOX9 in development and progression of cancer. Understanding the functional roles of SOX9 and clinical relevance is crucial for developing novel treatments targeting CSCs in cancer.

Therapeutic efficacy, pharmacokinetic profiles, and toxicological activities of humanized antibody-drug conjugate Zt/g4-MMAE targeting RON receptor tyrosine kinase for cancer therapy

BACKGROUND

Aberrant expression of the RON receptor tyrosine kinase is a pathogenic feature and a validated drug target in various types of cancers. Currently, therapeutic antibodies targeting RON for cancer therapy are under intensive evaluation. Here we report the development and validation of a novel humanized anti-RON antibody-drug conjugate for cancer therapy.

METHODS

Antibody humanization was achieved by grafting sequences of complementarity-determining regions from mouse monoclonal antibody Zt/g4 into human IgG1/κ acceptor frameworks. The selected humanized Zt/g4 subclone H1L3 was conjugated with monomethyl auristatin E using a dipeptide linker to form H-Zt/g4-MMAE. Pharmacokinetic analysis of H-Zt/g4-MMAE was determined using hydrophobic interaction chromatography and a MMAE ADC ELISA kit. Biochemical and biological assays were used for measuring RON expression, internalization, cell viability and death. Therapeutic efficacies of H-Zt/g4-MMAE were validated in vivo using three pancreatic cancer xenograft models. Toxicological activities of H-Zt/g4-MMAE were determined in mouse and cynomolgus monkey.

RESULTS

H-Zt/g4-MMAE had a drug to antibody ratio of 3.77:1 and was highly stable in human plasma with a dissociation rate less than 5% within a 20 day period. H-Zt/g4-MMAE displayed a favorable pharmacokinetic profile in both mouse and cynomolgus monkey. In vitro, H-Zt/g4-MMAE induced RON internalization, which results in killing of pancreatic cancer cells with IC₅₀ values at 10-20 nM. In vivo, H-Zt/g4-MMAE inhibited pancreatic cancer xenograft growth with tumoristatic concentrations at 1~3 mg/kg bodyweight. Significantly, H-Zt/g4-MMAE eradicated tumors across multiple xenograft models regardless their chemoresistant and metastatic statuses. Moreover, H-Zt/g4-MMAE inhibited and eradicated xenografts mediated by pancreatic cancer stem-like cells and by primary cells from patient-derived tumors. Toxicologically, H-Zt/g4-MMAE is well tolerated in mice up to 60 mg/kg. In cynomolgus monkey, H-Zt/g4-MMAE up to 30 mg/kg had a manageable and reversible toxicity profile.

CONCLUSIONS

H-Zt/g4-MMAE is superior in eradication of pancreatic cancer xenografts with favorable pharmacokinetic profiles and manageable toxicological activities. These findings warrant the transition of H-Zt/g4-MMAE into clinical trials in the future.

A negative feedback loop between long noncoding RNA NBAT1 and Sox9 inhibits the malignant progression of gastric cancer cells

Long noncoding RNAs (lncRNAs) play critical roles in carcinogenesis and progression, and act as important gene expression modulators. Recent evidence indicates that lncRNA neuroblastoma associated transcript 1 (NBAT1) functions as a tumor suppressor in some types of human cancers. However, its functional role in the development of gastric cancer (GC) remains unknown. The aim of this research was to investigate the clinical significance and biological functions of NBAT1 in GC. NBAT1 was found to be significantly down-regulated in GC tissue. Decreased NBAT1 expression was correlated with poor differentiation, higher tumor stage and lymph node metastasis, and poor prognosis. Functional assays showed that NBAT1 inhibited GC proliferation, migration, and invasion. NBAT1 also suppressed proliferation, migration, and capillary tube formation of human umbilical vein endothelial cells (HUVECs). Mechanistically, NBAT1 interacted with Sox9, and reduced its protein stability by promoting it from polyubiquitination and proteasome-dependent degradation. Moreover, we revealed that Sox9 could occupy the NBAT1 promoter to inactivate its transcription. The negative feedback loop of NBAT1 and Sox9 continuously enhanced the suppressive effects. In conclusion, these findings suggest that feedback regulation of NBAT1 and Sox9 served as a critical effector in GC progression.

HNF1A is a novel oncogene that regulates human pancreatic cancer stem cell properties

The biological properties of pancreatic cancer stem cells (PCSCs) remain incompletely defined and the central regulators are unknown. By bioinformatic analysis of a human PCSC-enriched gene signature, we identified the transcription factor HNF1A as a putative central regulator of PCSC function. Levels of HNF1A and its target genes were found to be elevated in PCSCs and tumorspheres, and depletion of HNF1A resulted in growth inhibition, apoptosis, impaired tumorsphere formation, decreased PCSC marker expression, and downregulation of POU5F1/OCT4 expression. Conversely, HNF1A overexpression increased PCSC marker expression and tumorsphere formation in pancreatic cancer cells and drove pancreatic ductal adenocarcinoma (PDA) cell growth. Importantly, depletion of HNF1A in xenografts impaired tumor growth and depleted PCSC marker-positive cells in vivo. Finally, we established an HNF1A-dependent gene signature in PDA cells that significantly correlated with reduced survivability in patients. These findings identify HNF1A as a central transcriptional regulator of PCSC properties and novel oncogene in PDA.

SOX9-PDK1 axis is essential for glioma stem cell self-renewal and temozolomide resistance

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor with limited therapeutic options. Glioma stem cell (GSC) is thought to be greatly responsible for glioma tumor progression and drug resistance. But the molecular mechanisms of GSC deriving recurrence and drug resistance are still unclear. SOX9 (sex-determining region Y (SRY)-box9 protein), a transcription factor expressed in most solid tumors, is reported as a key regulator involved in maintaining cancer hallmarks including the GSCs state. Previously, we have observed that silencing of SOX9 suppressed glioma cells proliferation both in vitro and in vivo. Here, we found that SOX9 was essential for GSC self-renewal. Silencing of SOX9 down-regulated a broad range of stem cell markers and inhibited glioma cell colony and sphere formation. We identified pyruvate dehydrogenase kinase 1 (PDK1) as a target gene of SOX9 using microarray analyses. PDK1 inactivation greatly inhibited glioma cell colony and sphere formation and sensitized glioma spheres to temozolomide (TMZ) toxicity. In addition, SOX9-shRNA and PDK1 inhibitor could greatly sensitize GSC to TMZ in vivo. Taken together, our data reveals that SOX9-PDK1 axis is a key regulator of GSC self-renewal and GSC temozolomide resistance. These findings may provide help for future human GBM therapy.

HIF-3α Promotes Metastatic Phenotypes in Pancreatic Cancer by Transcriptional Regulation of the RhoC-ROCK1 Signaling Pathway

Hypoxia contributes to pancreatic cancer progression and promotes its growth and invasion. Previous research principally focused on hypoxia-inducible factor-1 alpha (HIF-1α) and HIF-2α (HIF1A and EPAS1) as the major hypoxia-associated transcription factors in pancreatic cancer. However, the role of HIF-3α (HIF3A) has not been investigated. Therefore, HIF-1α, HIF-2α, and HIF-3α expression levels were measured under normoxic and hypoxic conditions. In addition, HIF-3α expression was measured in human pancreatic cancer tissue specimens and the impact of altered HIF-3α expression on cell invasion and migration was investigated in vitro and in vivo, as well as the underlying mechanisms. Under hypoxic conditions, HIF-3α expression was stimulated in pancreatic cancer cells to a greater degree than HIF-1α and HIF-2α expression. HIF-3α protein levels were also elevated in pancreatic cancer tissues and correlated with reduced survival and greater local invasion and distant metastasis, whereas knockdown of HIF-3α, under hypoxic conditions, suppressed pancreatic cancer cell invasion and migration. Under normoxia, HIF-3α overexpression promoted pancreatic cancer cell invasion and migration and stimulated F-actin polymerization. In summary, HIF-3α promotes pancreatic cancer cell invasion and metastasis in vivo and promotes pancreatic cancer cell invasion and metastasis by transcriptionally activating the RhoC-ROCK1 signaling pathway.Implications: HIF3α is overexpressed in pancreatic cancer, and targeting the HIF3α/RhoC-ROCK1 signaling pathway may be a novel therapeutic approach for the treatment of pancreatic cancer invasion and metastasis. Mol Cancer Res; 16(1); 124-34. ©2017 AACR.

Protocol of the PANCALYZE trial: a multicenter, prospective study investigating the tumor biomarkers CXCR4, SMAD4, SOX9 and IFIT3 in patients with resected pancreatic adenocarcinoma to predict the pattern of recurrence of the disease

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies today with an urgent need for novel therapeutic strategies. Biomarker analysis helps to better understand tumor biology and might emerge as a tool to develop personalized therapies. The aim of the study is to investigate four promising biomarkers to predict the clinical course and particularly the pattern of tumor recurrence after surgical resection.

DESIGN

Patients undergoing surgery for PDAC can be enrolled into the PANCALYZE trial. Biomarker expression of CXCR4, SMAD4, SOX9 and IFIT3 will be prospectively assessed by immunohistochemistry and verified by rt.-PCR from tumor and adjacent healthy pancreatic tissue of surgical specimen. Immunohistochemistry expression pattern of all four biomarkers will be combined into a single score. Beginning with the hospital stay clinical data from enrolled patients will be collected and followed. Different adjuvant chemotherapy protocols will be used to create subgroups. The combined biomarker expression score will be correlated with the further clinical course of the patients to test the hypothesis if CXCR4 positive, SMAD4 negative, SOX9 positive, IFIT3 positive tumors will predominantly develop metastatic spread.

DISCUSSION

Pancreatic cancer is associated with different patterns of progression requiring personalized therapeutic strategies. Biomarker expression analysis might be a tool to predict the pattern of tumor recurrence and discriminate patients that develop systemic metastatic disease from those with tumors that rather develop local recurrence over time. This data might lead to personalized adjuvant treatment decisions as patients with tumors that stay localized might benefit from adjuvant local therapies like radiochemotherapy as compared to those with systemic recurrence who would benefit exclusively from chemotherapy. Moreover, the pattern of propagation might be a predefined characteristic of pancreatic cancer determined by the genetic signature of the tumor. In the future, biomarker expression analysis could be performed on tumor biopsies to develop personalized therapeutic pathways right after diagnosis of cancer.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00006179 .

Effects of shRNA-Mediated SOX9 Inhibition on Cell Proliferation and Apoptosis in Human HCC Cell Line Hep3B Mediated by Ultrasound-Targeted Microbubble Destruction (UTMD)

Hepatocellular carcinoma (HCC) is one of the most aggressive tumors in humans. The survival rate of patients is still very poor as current therapies offer limited treatment efficacy. Therefore, it is necessary to explore novel and more effective strategies to treat HCC. Recently, Ultrasound-targeted microbubble destruction (UTMD) has been shown to be a better alternative to viral vectors in delivering plasmid DNA into cells. In this study, we thus first determined the effect of combining UTMD with effectene on the transfection efficiency in human Hep3B cells. Transfection rate of the [effectene + shRNA-SOX9 + UTMD] group was the highest among the five groups, and were significantly higher than that of the [effectene + shRNA-SOX9] or [shRNA-SOX9 + UTMD] groups, while there was no significant difference between [shRNA-SOX9 alone] and [shRNA-SOX9 + UTMD] groups. Expression of SOX9 mRNA and protein was the lowest in effectene + shRNA-SOX9 + UTMD group. Moreover, transfection of shRNA-SOX9 with UTMD and effectene in combination could markedly inhibit the proliferation and induced cell apoptosis of Hep3B cells. These results suggest that the efficiency of gene delivery is remarkably increased when UTMD is combined with other transfection strategies, such as effectene. In conclusion, our research demonstrates that combining conventional transfection methods with UTMD achieves better transfection efficiency and that this can provide an improved gene delivery system for gene therapy.

Hypoxia inducible factor down-regulation, cancer and cancer stem cells (CSCs): ongoing success stories

In cancers, hypoxia inducible factor 1 (HIF-1) is an over-expressed transcription factor, which regulates a large set of genes involved in tumour vascularization, metastases, and cancer stem cells (CSCs) formation and self-renewal. This protein has been identified as a relevant target in oncology and several HIF-1 modulators are now marketed or in advanced clinical trials. The purpose of this review is to summarize the advances in the understanding of its regulation and its inhibition, from the medicinal chemist point of view. To this end, we selected in the recent literature relevant examples of "hit" compounds, including small-sized organic molecules, pseudopeptides and nano-drugs, exhibiting in vitro and/or in vivo both anti-HIF-1 and anti-tumour activities. Whenever possible, a particular emphasis has been dedicated to compounds that selectively target CSCs.

Sox9 mediated transcriptional activation of FOXK2 is critical for colorectal cancer cells proliferation

FOXK2, which belongs to the fork head DNA binding protein family, has been shown to play a critical role in tumorigenesis. Here, we detected FOXK2 expression and its clinical significance in colorectal cancer, which has not been fully investigated before. Results from public database and our cohort indicated that FOXK2 was transcriptionally activated in colorectal cancer tissues compared to non-cancer tissues. High expression of FOXK2 was significantly correlated with poor survival. In vitro cell experiments suggested that FOXK2 promoted cell proliferation. Furthermore, we found that oncogene SOX9 was responsible for the up-regulation of FOXK2 by directly binding on its promoter. Depletion of FOXK2 attenuated SOX9 induced cell growth. In addition, we observed that the expression of FOXK2 was significantly associated with the expression of SOX9 both in the public database and our colorectal cancer tissues. The patients with SOX9⁺FOXK2⁺ had a poor overall survival (p = 0.0084). In conclusion, our data suggested that SOX9 transcriptionally activated FOXK2 was involved in the pathogenesis of colorectal cancer and might be a novel target for colorectal cancer therapy.

Overexpression of IFN-induced protein with tetratricopeptide repeats 3 (IFIT3) in pancreatic cancer: cellular "pseudoinflammation" contributing to an aggressive phenotype

Inflammation contributes to important traits that cancer cells acquire during malignant progression. Gene array data recently identified upregulation of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) in aggressive pancreatic cancer cells. IFIT3 belongs to the group of interferon stimulated genes (ISG), can be induced by several cellular stress stimuli and by its tetratricopeptide repeats interacts with a multitude of cellular proteins.

Upregulation of IFIT3 was confirmed in the aggressive pancreatic cancer cell line L3.6pl compared with its less aggressive cell line of origin, COLO357FG. Transgenic induction of IFIT3 expression in COLO357FG resulted in greater mass of orthotopic tumors and higher prevalence of metastases. Several important traits that mediate malignancy were altered by IFIT3: increased VEGF and IL-6 secretion, chemoresistance and decreased starvation-induced apoptosis. IFIT3 showed binding to JNK and STAT1, the latter being an important inducer of IFIT3 expression. Despite still being alterable by “classical” IFN or NFκB signaling, our findings indicate constitutive - possibly auto-regulated - upregulation of IFIT3 in L3.6pl without presence of an adequate inflammatory stimulus. The transcription factor SOX9, which is linked to regulation of hypoxia-related genes, was identified as a key mediator of upregulation of the oncogene IFIT3 and thereby sustaining a “pseudoinflammatory” cellular condition.

Sox9 Controls Self-Renewal of Oncogene Targeted Cells and Links Tumor Initiation and Invasion

Sox9 is a transcription factor expressed in most solid tumors. However, the molecular mechanisms underlying Sox9 function during tumorigenesis remain unclear. Here, using a genetic mouse model of basal cell carcinoma (BCC), the most frequent cancer in humans, we show that Sox9 is expressed from the earliest step of tumor formation in a Wnt/β-catenin-dependent manner. Deletion of Sox9 together with the constitutive activation of Hedgehog signaling completely prevents BCC formation and leads to a progressive loss of oncogene-expressing cells. Transcriptional profiling of oncogene-expressing cells with Sox9 deletion, combined with in vivo ChIP sequencing, uncovers a cancer-specific gene network regulated by Sox9 that promotes stemness, extracellular matrix deposition, and cytoskeleton remodeling while repressing epidermal differentiation. Our study identifies the molecular mechanisms regulated by Sox9 that link tumor initiation and invasion.

The intricate role of CXCR4 in cancer

Chemokines mediate numerous physiological and pathological processes related primarily to cell homing and migration. The chemokine CXCL12, also known as stromal cell-derived factor-1, binds the G-protein-coupled receptor CXCR4, which, through multiple divergent pathways, leads to chemotaxis, enhanced intracellular calcium, cell adhesion, survival, proliferation, and gene transcription. CXCR4, initially discovered for its involvement in HIV entry and leukocytes trafficking, is overexpressed in more than 23 human cancers. Cancer cell CXCR4 overexpression contributes to tumor growth, invasion, angiogenesis, metastasis, relapse, and therapeutic resistance. CXCR4 antagonism has been shown to disrupt tumor-stromal interactions, sensitize cancer cells to cytotoxic drugs, and reduce tumor growth and metastatic burden. As such, CXCR4 is a target not only for therapeutic intervention but also for noninvasive monitoring of disease progression and therapeutic guidance. This review provides a comprehensive overview of the biological involvement of CXCR4 in human cancers, the current status of CXCR4-based therapeutic approaches, as well as recent advances in noninvasive imaging of CXCR4 expression.