HAb18G/CD147 promotes pSTAT3-mediated pancreatic cancer development via CD44s

The effects of CypA on apoptosis: potential target for the treatment of diseases

Cyclophilin A (CypA), the first member of cyclophilins, is distributed extensively in eukaryotic and prokaryotic cells, primarily localized in the cytoplasm. In addition to acting as an intracellular receptor for cyclosporin A (CSA), CypA plays a crucial role in diseases such as aging and tumorigenesis. Apoptosis, a form of programmed cell death, is able to balance the rate of cell viability and death. In this review, we focus on the effects of CypA on apoptosis and the relationship between specific mechanisms of CypA promoting or inhibiting apoptosis and diseases, including tumorigenesis, cardiovascular diseases, organ injury, and microbial infections. Notably, the process of CypA promoting or inhibiting apoptosis is closely related to disease development. Finally, future prospects for the association of CypA and apoptosis are discussed, and a comprehensive understanding of the effects of CypA on apoptosis in relation to diseases is expected to provide new insights into the design of CypA as a therapeutic target for diseases. KEY POINTS: • Understand the effect of CypA on apoptosis. • CypA affects apoptosis through specific pathways. • The effect of CypA on apoptosis is associated with a variety of disease processes.

CD147-K148me2-Driven Tumor Cell-Macrophage Crosstalk Provokes NSCLC Immunosuppression via the CCL5/CCR5 Axis

Immunosuppression is a major hallmark of tumor progression in non-small cell lung cancer (NSCLC). Cluster of differentiation 147 (CD147), an important pro-tumorigenic factor, is closely linked to NSCLC immunosuppression. However, the role of CD147 di-methylation in the immunosuppressive tumor microenvironment (TME) remains unclear. Here, di-methylation of CD147 at Lys148 (CD147-K148me2) is identified as a common post-translational modification (PTM) in NSCLC that is significantly associated with unsatisfying survival outcomes among NSCLC sufferers, especially those in the advanced stages of the disease. The methyltransferase NSD2 catalyzes CD147 to generate CD147-K148me2. Further analysis demonstrates that CD147-K148me2 reestablishes the immunosuppressive TME and promotes NSCLC progression. Mechanistically, this modification promotes the interaction between cyclophilin A (CyPA) and CD147, and in turn, increases CCL5 gene transcription by activating p38-ZBTB32 signaling, leading to increased NSCLC cell-derived CCL5 secretion. Subsequently, CD147-K148me2-mediated CCL5 upregulation facilitates M2-like tumor-associated macrophage (TAM) infiltration in NSCLC tissues via CCL5/CCR5 axis-dependent intercellular crosstalk between tumor cells and macrophages, which is inhibited by blocking CD147-K148me2 with the targeted antibody 12C8. Overall, this study reveals the role of CD147-K148me2-driven intercellular crosstalk in the development of NSCLC immunosuppression, and provides a potential interventional strategy for PTM-targeted NSCLC therapy.

SETDB1-mediated CD147-K71 di-methylation promotes cell apoptosis in non-small cell lung cancer

Protein post-translational modifications (PTMs) are at the heart status of cellular signaling events and broadly involved in tumor progression. CD147 is a tumor biomarker with various PTMs, promoting tumor metastasis and metabolism reprogramming. Nevertheless, the relationship between the PTMs of CD147 and apoptosis has not been reported. In our study, we produced a specific anti-CD147-K71 di-methylation (CD147-K71me2) antibody by immunizing with a di-methylated peptide and observed that the level of CD147-K71me2 in non-small cell lung cancer (NSCLC) tissues were lower than that in NSCLC adjacent tissues. SETDB1 was identified as the methyltransferase catalyzing CD147 to generate CD147-K71me2. RNA-seq showed that FOSB was the most significant differentially expressed gene (DEG) between wild-type CD147 (CD147-WT) and K71-mutant CD147 (CD147-K71R) groups. Subsequently, we found that CD147-K71me2 promoted the expression of FOSB by enhancing the phosphorylation of p38, leading to tumor cell apoptosis. In vivo experiments showed that CD147-K71me2 significantly inhibited tumor progression by promoting cell apoptosis. Taken together, our findings indicate the inhibitory role of CD147-K71me2 in tumor progression from the perspective of post-translational modification, which is distinct from the pro-cancer function of CD147 itself, broadening our perspective on tumor-associated antigen CD147.

Insights into the complex interactions between Rab22a and extracellular vesicles in cancers

INTRODUCTION

Oncogenic Ras-related GTP-binding proteins, referred to as Rabs, are characterized by their intricate interactions with upstream, downstream molecules, and notably, extracellular vesicles (EVs). While the expansive family of Rabs and their associated signaling pathways have been exhaustively dissected, Rab22a emerges as an entity of outstanding interest, owing to its potent influence in many biological processes and its conspicuous correlation with cancer metastasis and migration. A burgeoning interest in the interactions between Rab22a and EVs in the field of oncology underscores the necessity for more in-depth reviews and scholarly discourses.

METHODS

We performed a review based on published original and review articles related to Rab22a, tumor, microRNA, exosome, microvesicles, EVs, CD147, lysosome, degradation, endosomal recycling, etc. from PubMed, Web of Science and Google Scholar databases.

RESULTS AND CONCLUSIONS

We summarize the regulatory processes governing the expression of Rab22a and the mutants of Rab22a. Notably, the present understanding of complex interactions between Rab22a and EVs are highlighted, encompassing both the impact of Rab22a on the genesis of EVs and the role of EVs that are affected by Rab22a mutants in propelling tumor advancement. The dynamic interaction between Rab22a and EVs plays a significant role in the progression of tumors, and it can provide novel insights into the pathogenesis of cancers and the development of new therapeutic targets.

CD147: an integral and potential molecule to abrogate hallmarks of cancer

CD147 also known as EMMPRIN, basigin, and HAb18G, is a single-chain type I transmembrane protein shown to be overexpressed in aggressive human cancers of CNS, head and neck, breasts, lungs, gastrointestinal, genitourinary, skin, hematological, and musculoskeletal. In these malignancies, the molecule is integral to the diverse but complimentary hallmarks of cancer: it is pivotal in cancerous proliferative signaling, growth propagation, cellular survival, replicative immortality, angiogenesis, metabolic reprogramming, immune evasion, invasion, and metastasis. CD147 also has regulatory functions in cancer-enabling characteristics such as DNA damage response (DDR) and immune evasion. These neoplastic functions of CD147 are executed through numerous and sometimes overlapping molecular pathways: it transduces signals from upstream molecules or ligands such as cyclophilin A (CyPA), CD98, and S100A9; activates a repertoire of downstream molecules and pathways including matrix metalloproteinases (MMPs)-2,3,9, hypoxia-inducible factors (HIF)-1/2α, PI3K/Akt/mTOR/HIF-1α, and ATM/ATR/p53; and also functions as an indispensable chaperone or regulator to monocarboxylate, fatty acid, and amino acid transporters. Interestingly, induced loss of functions to CD147 prevents and reverses the acquired hallmarks of cancer in neoplastic diseases. Silencing of Cd147 also alleviates known resistance to chemoradiotherapy exhibited by malignant tumors like carcinomas of the breast, lung, pancreas, liver, gastric, colon, ovary, cervix, prostate, urinary bladder, glioblastoma, and melanoma. Targeting CD147 antigen in chimeric and induced-chimeric antigen T cell or antibody therapies is also shown to be safer and more effective. Moreover, incorporating anti-CD147 monoclonal antibodies in chemoradiotherapy, oncolytic viral therapy, and oncolytic virus-based-gene therapies increases effectiveness and reduces on and off-target toxicity. This study advocates the expedition and expansion by further exploiting the evidence acquired from the experimental studies that modulate CD147 functions in hallmarks of cancer and cancer-enabling features and strive to translate them into clinical practice to alleviate the emergency and propagation of cancer, as well as the associated clinical and social consequences.

Niclosamide improves cancer immunotherapy by modulating RNA-binding protein HuR-mediated PD-L1 signaling

BACKGROUND

Immune checkpoint blockade (ICB) represents a revolutionary advance in cancer treatment but remains limited success in triple-negative breast cancer (TNBC). Here we aim to explore the mechanism of RNA-binding protein (RBP) HuR in cancer immune evasion by post-transcriptionally regulating PD-L1 and evaluate the potential of HuR inhibition to improve immune response.

METHODS

The binding between HuR and PD-L1 mRNA was determined by ribonucleoprotein immunoprecipitation and RNA pull-down assays. The HuR knockout clones were established by CRISPR/Cas9 technology. The protein levels were assessed by Western blot, immunohistochemistry, and immunocytochemistry. The function and molecular mechanism of HuR-PD-L1 were determined by in vitro T cell activation and killing assay and in vivo efficacy assay.

RESULTS

We found that HuR directly bound to and stabilized PD-L1 mRNA. Knocking out HuR reduced PD-L1 levels and promoted T cell activation. We discovered that niclosamide reduced PD-L1 by inhibiting HuR cytoplasmic translocation, and diminished glycosylation of PD-L1. Niclosamide enhanced T cell-mediated killing of cancer cells and significantly improved the efficacy of anti-PD-1 immunotherapy in two syngeneic animal tumor models.

CONCLUSION

We identified HuR as a novel posttranscriptional regulator of PD-L1, which plays an important role in tumor immune evasion. Niclosamide might be a promising repurposed drug to improve the patient response to immunotherapy by targeting HuR-PD-L1 axis. Our study demonstrates a novel strategy for targeting HuR/PD-L1 and provides the first proof-of-principle for repurposing niclosamide as a HuR inhibitor to overcome cancer immune evasion and improve response to ICB immunotherapy.

Repurposing Niclosamide as a Novel Anti-SARS-CoV-2 Drug by Restricting Entry Protein CD147

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the global coronavirus disease 2019 (COVID-19) pandemic, and the search for effective treatments has been limited. Furthermore, the rapid mutations of SARS-CoV-2 have posed challenges to existing vaccines and neutralizing antibodies, as they struggle to keep up with the increased viral transmissibility and immune evasion. However, there is hope in targeting the CD147-spike protein, which serves as an alternative point for the entry of SARS-CoV-2 into host cells. This protein has emerged as a promising therapeutic target for the development of drugs against COVID-19. Here, we demonstrate that the RNA-binding protein Human-antigen R (HuR) plays a crucial role in the post-transcriptional regulation of CD147 by directly binding to its 3'-untranslated region (UTR). We observed a decrease in CD147 levels across multiple cell lines upon HuR depletion. Furthermore, we identified that niclosamide can reduce CD147 by lowering the cytoplasmic translocation of HuR and reducing CD147 glycosylation. Moreover, our investigation revealed that SARS-CoV-2 infection induces an upregulation of CD147 in ACE2-expressing A549 cells, which can be effectively neutralized by niclosamide in a dose-dependent manner. Overall, our study unveils a novel regulatory mechanism of regulating CD147 through HuR and suggests niclosamide as a promising therapeutic option against COVID-19.

Repurposing niclosamide as a novel anti-SARS-Cov-2 drug by restricting entry protein CD147

Background The burst of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the global COVID-19 pandemic. But until today only limited numbers of drugs are discovered to treat COVID-19 patients. Even worse, the rapid mutations of SARS-CoV-2 compromise the effectiveness of existing vaccines and neutralizing antibodies due to the increased viral transmissibility and immune escape. CD147-spike protein, one of the entries of SRAR-CoV-2 into host cells, has been reported as a promising therapeutic target for developing drugs against COVID-19. Methods CRISPR-Cas9 induced gene knockout, western blotting, tet-off protein overexpression, ribonucleoprotein IP and RNA-IP were used to confirm the regulation of HuR on mRNA of CD147. Regulation of niclosamide on HuR nucleo-translocation was assessed by immunofluorescence staining of cell lines, IHC staining of tissue of mouse model and western blotting. Finally, the suppression of niclosamide on SARS-CoV-2 infection induced CD147 was evaluated by ACE2-expressing A549 cells and western blotting. Results We first discovered a novel regulation mechanism of CD147 via the RNA-binding protein HuR. We found that HuR regulates CD147 post-transcription by directly bound to its 3'-UTR. The loss of HuR reduced CD147 in multiple cell lines. Niclosamide inhibited CD147 function by blocking HuR cytoplasmic translocation and diminishing CD147 glycosylation. SARS-CoV-2 infection induced CD147 in ACE2-expressing A549 cells, which could be neutralized by niclosamide in a dose-dependent manner. Conclusion Together, our study reveals a novel regulation mechanism of CD147 and niclosamide can be repurposed as an effective COVID-19 drug by targeting the virus entry, CD147-spike protein.

Cyclophilin A/CD147 Interaction: A Promising Target for Anticancer Therapy

Cyclophilin A (CypA), which has peptidyl-prolyl cis-trans isomerase (PPIase) activity, regulates multiple functions of cells by binding to its extracellular receptor CD147. The CypA/CD147 interaction plays a crucial role in the progression of several diseases, including inflammatory diseases, coronavirus infection, and cancer, by activating CD147-mediated intracellular downstream signaling pathways. Many studies have identified CypA and CD147 as potential therapeutic targets for cancer. Their overexpression promotes growth, metastasis, therapeutic resistance, and the stem-like properties of cancer cells and is related to the poor prognosis of patients with cancer. This review aims to understand the biology and interaction of CypA and CD147 and to review the roles of the CypA/CD147 interaction in cancer pathology and the therapeutic potential of targeting the CypA/CD147 axis. To validate the clinical significance of the CypA/CD147 interaction, we analyzed the expression levels of PPIA and BSG genes encoding CypA and CD147, respectively, in a wide range of tumor types using The Cancer Genome Atlas (TCGA) database. We observed a significant association between PPIA/BSG overexpression and poor prognosis, such as a low survival rate and high cancer stage, in several tumor types. Furthermore, the expression of PPIA and BSG was positively correlated in many cancers. Therefore, this review supports the hypothesis that targeting the CypA/CD147 interaction may improve treatment outcomes for patients with cancer.

Rab22a Promotes Epithelial-Mesenchymal Transition in Papillary Thyroid Carcinoma by Activating PI3K/AKT/mTOR Signaling Pathway

Background

Rab22a is a member of the RAS superfamily, involved in early endosome formation and intracellular vesicle transport. Rab22a is significantly upregulated in a variety of malignant tumors. However, its function in thyroid cancer has never been addressed.

Methods

The expression of Rab22a in paraffin sections of 101 patients was detected by immunohistochemical staining. By upregulating and downregulating the expression of Rab22a in thyroid cancer cell lines, the effect of Rab22a on cell proliferation, invasion, and migration was analyzed. Co-IP was employed, and the interaction between Rab22a and PI3Kp85α was shown. The function of Rab22a on PI3K/AKT/mTOR signaling and epithelial-mesenchymal transition (EMT) was further studied by western blot analysis.

Results

Immunostaining showed that Rab22a was significantly overexpressed in thyroid cancer tissues but negative in adjacent normal tissues or nodular goiters. The proliferation, migration, invasion, and EMT in papillary thyroid carcinoma cell lines were enhanced upon Rab22a overexpression but inhibited after knocking down Rab22a. The co-IP assay demonstrated an interaction between Rab22a and PI3K85α, an effector of PI3K. We further found that Rab22a can activate the PI3K/AKT/mTOR signaling pathway. However, the ability of Rab22a to promote the proliferation, invasion, migration, and EMT of papillary thyroid carcinoma cells was significantly inhibited after being treated with LY294002, a PI3K inhibitor.

Conclusions

Rab22a can promote the EMT process and enhance proliferation, migration, and invasion of papillary thyroid carcinoma cells by activating the PI3K/AKT/mTOR signaling pathway. Our study provides new pathological diagnosis clues and clinical treatment targets for thyroid cancer.

Resistance to Gemcitabine in Pancreatic Ductal Adenocarcinoma: A Physiopathologic and Pharmacologic Review

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a poor prognosis and inadequate response to treatment. Many factors contribute to this therapeutic failure: lack of symptoms until the tumor reaches an advanced stage, leading to late diagnosis; early lymphatic and hematic spread; advanced age of patients; important development of a pro-tumoral and hyperfibrotic stroma; high genetic and metabolic heterogeneity; poor vascular supply; a highly acidic matrix; extreme hypoxia; and early development of resistance to the available therapeutic options. In most cases, the disease is silent for a long time, andwhen it does become symptomatic, it is too late for ablative surgery; this is one of the major reasons explaining the short survival associated with the disease. Even when surgery is possible, relapsesare frequent, andthe causes of this devastating picture are the low efficacy ofand early resistance to all known chemotherapeutic treatments. Thus, it is imperative to analyze the roots of this resistance in order to improve the benefits of therapy. PDAC chemoresistance is the final product of different, but to some extent, interconnected factors. Surgery, being the most adequate treatment for pancreatic cancer and the only one that in a few selected cases can achieve longer survival, is only possible in less than 20% of patients. Thus, the treatment burden relies on chemotherapy in mostcases. While the FOLFIRINOX scheme has a slightly longer overall survival, it also produces many more adverse eventsso that gemcitabine is still considered the first choice for treatment, especially in combination with other compounds/agents. This review discusses the multiple causes of gemcitabine resistance in PDAC.

Mini-Review: Can the Metastatic Cascade Be Inhibited by Targeting CD147/EMMPRIN to Prevent Tumor Recurrence?

Solid tumors metastasize very early in their development, and once the metastatic cell is lodged in a remote organ, it can proliferate to generate a metastatic lesion or remain dormant for long periods. Dormant cells represent a real risk for future tumor recurrence, but because they are typically undetectable and insensitive to current modalities of treatment, it is difficult to treat them in time. We describe the metastatic cascade, which is the process that allows tumor cells to detach from the primary tumor, migrate in the tissue, intravasate and extravasate the lymphatics or a blood vessel, adhere to a remote tissue and eventually outgrow. We focus on the critical enabling role of the interactions between tumor cells and immune cells, especially macrophages, in driving the metastatic cascade, and on those stages that can potentially be targeted. In order to prevent the metastatic cascade and tumor recurrence, we would need to target a molecule that is involved in all of the steps of the process, and evidence is brought to suggest that CD147/EMMPRIN is such a protein and that targeting it blocks metastasis and prevents tumor recurrence.

Loss of basigin expression in uterine cells leads to subfertility in female mice†

Basigin (BSG) is a transmembrane glycoprotein involved in cell proliferation, angiogenesis, and tissue remodeling. BSG has been shown to be essential for male and female reproduction although little is known about its role in normal uterine function. To study the potential function of BSG in the female reproductive tract, we generated mice with conditional knockout of Bsg in uterine cells using progesterone receptor-Cre and hypothesized that BSG is required for normal pregnancy in mice. Fertility study data showed that the conditional knockout mice had significantly reduced fertility compared to controls. Ovarian function of the conditional knockout mice appeared normal with no difference in the number of superovulated oocytes collected or in serum progesterone levels between the conditional knockout and the control mice. Uterine tissues collected at various times of gestation showed increased abnormalities in implantation, decidualization, placentation, and parturition in the conditional knockout mice. Uterine cross sections on Day 5 of pregnancy showed implantation failure and abnormal uterine epithelial differentiation in a large proportion of the conditional knockout mice. There was a compromised decidual response to artificial decidualization stimuli and decreased mRNA and protein levels for decidualization genes in the uteri of the conditional knockout mice. We also observed altered protein expression of monocarboxylate transporter 1 (MCT1), as well as impaired angiogenesis in the conditional knockout uteri compared to the controls. These results support that BSG is required for successful pregnancy through its functions in implantation and decidualization.

CD147 receptor is essential for TFF3-mediated signaling regulating colorectal cancer progression

Major gaps in understanding the molecular mechanisms of colorectal cancer (CRC) progression and intestinal mucosal repair have hampered therapeutic development for gastrointestinal disorders. Trefoil factor 3 (TFF3) has been reported to be involved in CRC progression and intestinal mucosal repair; however, how TFF3 drives tumors to become more aggressive or metastatic and how TFF3 promotes intestinal mucosal repair are still poorly understood. Here, we found that the upregulated TFF3 in CRC predicted a worse overall survival rate. TFF3 deficiency impaired mucosal restitution and adenocarcinogenesis. CD147, a membrane protein, was identified as a binding partner for TFF3. Via binding to CD147, TFF3 enhanced CD147-CD44s interaction, resulting in signal transducer and activator of transcription 3 (STAT3) activation and prostaglandin G/H synthase 2 (PTGS2) expression, which were indispensable for TFF3-induced migration, proliferation, and invasion. PTGS2-derived PGE2 bound to prostaglandin E2 receptor EP4 subtype (PTGER4) and contributed to TFF3-stimulated CRC progression. Solution NMR studies of the TFF3-CD147 interaction revealed the key residues critical for TFF3 binding and the induction of PTGS2 expression. The ability of TFF3 to enhance mucosal restitution was weakened by a PTGS2 inhibitor. Blockade of TFF3-CD147 signaling using competitive inhibitory antibodies or a PTGS2 inhibitor reduced CRC lung metastasis in mice. Our findings bring strong evidence that CD147 is a novel receptor for TFF3 and PTGS2 signaling is critical for TFF3-induced mucosal restitution and CRC progression, which widens and deepens the understanding of the molecular function of trefoil factors.

A Critical Role of Peptidylprolyl Isomerase A Pseudogene 22/microRNA-197-3p/Peptidylprolyl Isomerase A Axis in Hepatocellular Carcinoma

The burden of hepatocellular carcinoma (HCC) worldwide is increasing over time, while the underlying molecular mechanism of HCC development is still under exploration. Pseudogenes are classified as a special type of long non-coding RNAs (lncRNAs), and they played a vital role in regulating tumor-associated gene expression. Here, we report that a pseudogene peptidylprolyl isomerase A pseudogene 22 (PPIAP22) and its parental gene peptidylprolyl isomerase A (PPIA) were upregulated in HCC and were associated with the clinical outcomes of HCC. Further investigation revealed that PPIAP22 might upregulate the expression of PPIA through sponging microRNA (miR)-197-3p, behaving as competing endogenous RNA (ceRNA). PPIA could participate in the development of HCC by regulating mRNA metabolic process and tumor immunity based on the functional enrichment analysis. We also found a strong correlation between the expression levels of PPIA and the immune cell infiltration or the expression of chemokines, especially macrophage, C-C motif chemokine ligand 15 (CCL15), and C-X-C motif chemokine ligand 12 (CXCL12). Our findings demonstrate that the PPIAP22/miR-197-3p/PPIA axis plays a vital role in the progression of HCC by increasing the malignancy of tumor cells and regulating the immune cell infiltration, especially macrophage, through CCL15-CCR1 or CXCL12-CXCR4/CXCR7 pathways.

Targeted degradation of CD147 proteins in melanoma

CD147 is a transmembrane glycoprotein and a member of immunoglobulin superfamily, is strongly expressed in melanoma cells. CD147 has a pivotal role in tumor development. Therefore, it is a potential drug target for melanoma. In this article, we report the discovery of the first CD147 protein proteolysis targeting chimeras (PROTACs) derived from the natural product pseudolaric acid B (PAB). The representative compound 6a effectively induced degradation of CD147 and inhibited melanoma cells in vitro and in vivo. 6a could be used as the novel type of anticancer agent or as a part of the molecular biology research toolkit used in the gain-of-function study of the dynamic roles of CD147 in cancer networks.

STAT3, the Challenge for Chemotherapeutic and Radiotherapeutic Efficacy

Chemoradiotherapy is one of the most effective and extensively used strategies for cancer treatment. Signal transducer and activator of transcription 3 (STAT3) regulates vital biological processes, such as cell proliferation and cell growth. It is constitutively activated in various cancers and limits the application of chemoradiotherapy. Accumulating evidence suggests that STAT3 regulates resistance to chemotherapy and radiotherapy and thereby impairs therapeutic efficacy by mediating its feedback loop and several target genes. The alternative splicing product STAT3β is often identified as a dominant-negative regulator, but it enhances sensitivity to chemotherapy and offers a new and challenging approach to reverse therapeutic resistance. We focus here on exploring the role of STAT3 in resistance to receptor tyrosine kinase (RTK) inhibitors and radiotherapy, outlining the potential of targeting STAT3 to overcome chemo(radio)resistance for improving clinical outcomes, and evaluating the importance of STAT3β as a potential therapeutic approach to overcomes chemo(radio)resistance. In this review, we discuss some new insights into the effect of STAT3 and its subtype STAT3β on chemoradiotherapy sensitivity, and we explore how these insights influence clinical treatment and drug development for cancer.

Pancreatic Adenocarcinoma: Unconventional Approaches for an Unconventional Disease

This review highlights current treatments, limitations, and pitfalls in the management of pancreatic cancer and discusses current research in novel targets and drug development to overcome these clinical challenges. We begin with a review of the clinical landscape of pancreatic cancer, including genetic and environmental risk factors, as well as limitations in disease diagnosis and prevention. We next discuss current treatment paradigms for pancreatic cancer and the shortcomings of targeted therapy in this disease. Targeting major driver mutations in pancreatic cancer, such as dysregulation in the KRAS and TGFβ signaling pathways, have failed to improve survival outcomes compared with nontargeted chemotherapy; thus, we describe new advances in therapy such as Ras-binding pocket inhibitors. We then review next-generation approaches in nanomedicine and drug delivery, focusing on preclinical advancements in novel optical probes, antibodies, small-molecule agents, and nucleic acids to improve surgical outcomes in resectable disease, augment current therapies, expand druggable targets, and minimize morbidity. We conclude by summarizing progress in current research, identifying areas for future exploration in drug development and nanotechnology, and discussing future prospects for management of this disease.

Identification and Validation of an Aspergillus nidulans Secondary Metabolite Derivative as an Inhibitor of the Musashi-RNA Interaction

RNA-binding protein Musashi-1 (MSI1) is a key regulator of several stem cell populations. MSI1 is involved in tumor proliferation and maintenance, and it regulates target mRNAs at the translational level. The known mRNA targets of MSI1 include Numb, APC, and P21^WAF-1, key regulators of Notch/Wnt signaling and cell cycle progression, respectively. In this study, we aim to identify small molecule inhibitors of MSI1-mRNA interactions, which could block the growth of cancer cells with high levels of MSI1. Using a fluorescence polarization (FP) assay, we screened small molecules from several chemical libraries for those that disrupt the binding of MSI1 to its consensus RNA. One cluster of hit compounds is the derivatives of secondary metabolites from Aspergillus nidulans. One of the top hits, Aza-9, from this cluster was further validated by surface plasmon resonance and nuclear magnetic resonance spectroscopy, which demonstrated that Aza-9 binds directly to MSI1, and the binding is at the RNA binding pocket. We also show that Aza-9 binds to Musashi-2 (MSI2) as well. To test whether Aza-9 has anti-cancer potential, we used liposomes to facilitate Aza-9 cellular uptake. Aza-9-liposome inhibits proliferation, induces apoptosis and autophagy, and down-regulates Notch and Wnt signaling in colon cancer cell lines. In conclusion, we identified a series of potential lead compounds for inhibiting MSI1/2 function, while establishing a framework for identifying small molecule inhibitors of RNA binding proteins using FP-based screening methodology.

CD147 promotes DNA damage response and gemcitabine resistance via targeting ATM/ATR/p53 and affects prognosis in pancreatic cancer

The acquisition of chemoresistance is a major clinical challenge for pancreatic cancer (PC) treatment. Chemoresistance is largely attributed to aberrant DNA damage repair. However, the underlying mechanisms of chemoresistance in pancreatic cancer remain unclear. Here, we showed that CD147 was strongly correlated to DNA damage response (DDR) indices and poor prognosis in pancreatic ductal adenocarcinoma (PDAC) patients. CD147 knockdown or monoclonal antibodies improved the killing effects of gemcitabine in gemcitabine resistant cells, exhibiting reduced activation of ATM/p53. Moreover, we found the interaction of CD147 with ATM, ATR and p53, which was augmented in gemcitabine resistant cells. High CD147/p-ATM/p-ATR/p-p53 cytoplasmic expression associated with poor survival of PC patients. Our studies thus identify CD147 as a critical player in DDR programing that affects gemcitabine therapeutic outcomes of pancreatic cancer patients.

Targeting the interaction between RNA-binding protein HuR and FOXQ1 suppresses breast cancer invasion and metastasis

Patients diagnosed with metastatic breast cancer have a dismal 5-year survival rate of only 24%. The RNA-binding protein Hu antigen R (HuR) is upregulated in breast cancer, and elevated cytoplasmic HuR correlates with high-grade tumors and poor clinical outcome of breast cancer. HuR promotes tumorigenesis by regulating numerous proto-oncogenes, growth factors, and cytokines that support major tumor hallmarks including invasion and metastasis. Here, we report a HuR inhibitor KH-3, which potently suppresses breast cancer cell growth and invasion. Furthermore, KH-3 inhibits breast cancer experimental lung metastasis, improves mouse survival, and reduces orthotopic tumor growth. Mechanistically, we identify FOXQ1 as a direct target of HuR. KH-3 disrupts HuR–FOXQ1 mRNA interaction, leading to inhibition of breast cancer invasion. Our study suggests that inhibiting HuR is a promising therapeutic strategy for lethal metastatic breast cancer.

Wu et al. identify an inhibitor to the RNA-binding protein HuR, KH-3, that disrupts the interaction between HuR and target RNAs and inhibits human cancer growth and metastasis in mouse xenograft assays. This study suggests the therapeutic potential of targeting HuR in breast cancer with HuR overexpression.

Overview of the STAT-3 signaling pathway in cancer and the development of specific inhibitors

Signal transducer and activator of transcription (STAT) proteins represent novel therapeutic targets for the treatment of cancer. In particular, STAT-3 serves critical roles in several cellular processes, including the cell cycle, cell proliferation, cellular apoptosis and tumorigenesis. Persistent activation of STAT-3 has been reported in a variety of cancer types, and a poor prognosis of cancer may be associated with the phosphorylation level of STAT-3. Furthermore, elevated STAT-3 activity has been demonstrated in a variety of mammalian cancers, both in vitro and in vivo. This indicates that STAT-3 serves an important role in the progression of numerous cancer types. A significant obstacle in developing STAT-3 inhibitors is the demonstration of the antitumor efficacy in in vivo systems and the lack of animal models for human tumors. Therefore, it is crucial to determine whether available STAT-3 inhibitors are suitable for clinical trials. Moreover, further preclinical studies are necessary to focus on the impact of STAT-3 inhibitors on tumor cells. When considering STAT-3 hyper-activation in human cancer, selective targeting to these proteins holds promise for significant advancement in cancer treatment. In the present study, advances in our knowledge of the structure of STAT-3 protein and its regulatory mechanisms are summarized. Moreover, the STAT-3 signaling pathway and its critical role in malignancy are discussed, in addition to the development of STAT-3 inhibitors in various cancer types.

Detachment Activated CyPA/CD147 Induces Cancer Stem Cell Potential in Non-stem Breast Cancer Cells

BACKGROUND

Cancer stem cells (CSCs), responsible for cancer metastasis and recurrence, are generated from non-CSCs after chemo-radiation therapy. This study investigated the induction of CSC potential in non-stem breast cancer cells and the underlying molecular mechanisms in detachment culture.

METHODS

Bulk breast cancer cells, or sorted non-CSCs and CSCs were cultured under an attached or detached condition to assess CSC numbers, ability to form tumor spheres, expression of stemness markers, and chemoresistance. Lentivirus carrying CD147 shRNA or cDNA was used to manipulate CD147 expression, while CD147 ligand recombinant cyclophilin A (CyPA) or its inhibitor was used to activate or inhibit CD147 signaling.

RESULTS

Detachment promoted anoikis resistance, chemoresistance, sphere formation, self-renewal, and expression of stemness markers in breast cancer cells. Detachment increased functional ALDH⁺ or CD44^highCD24^-/low CSCs, and induced CSC potential in ALDH^- or CD44 ^low CD24^high non-CSCs. Upon detachment, both CD147 expression and CyPA secretion were enhanced, and CyPA-CD147 activation mediated detachment induced CSC potential in non-CSCs via STAT3 signaling. Clinically, CD147 and pSTAT3 were highly co-expressed and correlated with poor overall survival and tumor recurrence in breast cancer patients.

CONCLUSION

This study demonstrates that detachment induces the generation of CSCs from non-stem breast cancer cells via CyPA-CD147 signaling, indicating that targeting CD147 may serve as a potential novel therapeutic strategy for lethal metastatic breast cancer by eliminating induced CSCs.

Super-Resolution Microscopy Reveals Local Accumulation of Plasma Membrane Gangliosides at Neisseria meningitidis Invasion Sites

Neisseria meningitidis (meningococcus) is a Gram-negative bacterium responsible for epidemic meningitis and sepsis worldwide. A critical step in the development of meningitis is the interaction of bacteria with cells forming the blood-cerebrospinal fluid barrier, which requires tight adhesion of the pathogen to highly specialized brain endothelial cells. Two endothelial receptors, CD147 and the β2-adrenergic receptor, have been found to be sequentially recruited by meningococci involving the interaction with type IV pilus. Despite the identification of cellular key players in bacterial adhesion the detailed mechanism of invasion is still poorly understood. Here, we investigated cellular dynamics and mobility of the type IV pilus receptor CD147 upon treatment with pili enriched fractions and specific antibodies directed against two extracellular Ig-like domains in living human brain microvascular endothelial cells. Modulation of CD147 mobility after ligand binding revealed by single-molecule tracking experiments demonstrates receptor activation and indicates plasma membrane rearrangements. Exploiting the binding of Shiga (STxB) and Cholera toxin B (CTxB) subunits to the two native plasma membrane sphingolipids globotriaosylceramide (Gb3) and raft-associated monosialotetrahexosylganglioside GM1, respectively, we investigated their involvement in bacterial invasion by super-resolution microscopy. Structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM) unraveled accumulation and coating of meningococci with GM1 upon cellular uptake. Blocking of CTxB binding sites did not impair bacterial adhesion but dramatically reduced bacterial invasion efficiency. In addition, cell cycle arrest in G1 phase induced by serum starvation led to an overall increase of GM1 molecules in the plasma membrane and consequently also in bacterial invasion efficiency. Our results will help to understand downstream signaling events after initial type IV pilus-host cell interactions and thus have general impact on the development of new therapeutics targeting key molecules involved in infection.

Therapeutic anti-CD147 antibody sensitizes cells to chemoradiotherapy via targeting pancreatic cancer stem cells

We have previously demonstrated that anti-CD44s H4C4 or liposomal-delivered STAT3 inhibitor FLLL32 sensitized pancreatic cancer cells to radiotherapy through the elimination or inhibition of cancer stem cells (CSCs) and that HAb18G/CD147 promoted STAT3-mediated pancreatic tumor development by forming a signaling complex with CD44s. In this paper, we therefore explored whether anti-CD147 HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy via the targeting of CSCs. We tested the influence of HAb18IgG on the sensitivity of pancreatic cancer cells to chemoradiotherapy by clonogenic and MTT assays and on pancreatic CSCs by colony and sphere formation assays, flow cytometry, quantitative real-time RT-PCR (qRT-PCR) and stem cell transcription factors PCR array analysis. Changes in CD147 signaling were examined by immunoblot and reporter assays. We found that HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy by dose-dependently decreasing colony and sphere formation. Furthermore, HAb18IgG reduced the pancreatic CSC subpopulation and the expression of stem cell transcription factors OCT4, SOX2 and NANOG. Mechanistically, HAb18IgG inhibited CSCs by blocking CD44s-pSTAT3 signaling. The present findings indicated the promising therapeutic role of anti-CD147 HAb18IgG in suppressing pancreatic tumor initiation and overcoming post-chemoradiotherapy recurrence through the direct targeting of CSCs.

A novel antibody-drug conjugate, HcHAb18-DM1, has potent anti-tumor activity against human non-small cell lung cancer

Cluster of differentiation 147 (CD147), a transmembrane protein of the immunoglobulin superfamily, is a potential target of treatment against human non-small cell lung cancer (NSCLC). Although there have been exciting advances in epidermal growth factor receptor (EGFR)-targeted therapy for NSCLC in recent years, additional novel targeted agents are needed to improve the efficiency and to offer more options for patients. Antibody-drug conjugates (ADCs) utilize a chemical linker to conjugate cytotoxic drugs to a monoclonal antibody to maximize the delivery to target cells and minimize the delivery to other normal cells. The aim of this study was to prepare a novel anti-CD147 conjugate and examine the tumoricidal effect on NSCLC in vitro and in vivo. HcHAb18 was conjugated to the drug maytansinoid 1 (DM1) via a non-cleavable thioether linker (SMCC) to prepare HcHAb18-DM1 with an appropriate drug-antibody ratio (DAR). NSCLC cell lines expressing different levels of CD147 were tested in vitro to determine internalization, cell cycle arrest and cytotoxicity. In vivo efficacy and safety of HcHAb18-DM1 were evaluated in NSCLC xenograft mouse models. We found that HcHAb18-DM1 displayed an impressive potency in vitro and in vivo with a favorable safety profile. Upon binding to CD147, HcHAb18 could be internalized and delivered the payload DM1 to disturb mitotic spindle formation by microtubules. Target cells were arrested at G2/M phase and HcHAb18-DM1 exerted antiproliferative activity in vitro. Antigen-antibody binding and target cells with high growth rate were two integral prerequisites for exerting anti-tumor activity of HcHAb18-DM1. Therefore, we suggest HcHAb18-DM1 is a promising CD147-targeted therapeutic for NSCLC.

Natural product derivative Gossypolone inhibits Musashi family of RNA-binding proteins

BACKGROUND

The Musashi (MSI) family of RNA-binding proteins is best known for the role in post-transcriptional regulation of target mRNAs. Elevated MSI1 levels in a variety of human cancer are associated with up-regulation of Notch/Wnt signaling. MSI1 binds to and negatively regulates translation of Numb and APC (adenomatous polyposis coli), negative regulators of Notch and Wnt signaling respectively.

METHODS

Previously, we have shown that the natural product (-)-gossypol as the first known small molecule inhibitor of MSI1 that down-regulates Notch/Wnt signaling and inhibits tumor xenograft growth in vivo. Using a fluorescence polarization (FP) competition assay, we identified gossypolone (Gn) with a > 20-fold increase in Ki value compared to (-)-gossypol. We validated Gn binding to MSI1 using surface plasmon resonance, nuclear magnetic resonance, and cellular thermal shift assay, and tested the effects of Gn on colon cancer cells and colon cancer DLD-1 xenografts in nude mice.

RESULTS

In colon cancer cells, Gn reduced Notch/Wnt signaling and induced apoptosis. Compared to (-)-gossypol, the same concentration of Gn is less active in all the cell assays tested. To increase Gn bioavailability, we used PEGylated liposomes in our in vivo studies. Gn-lip via tail vein injection inhibited the growth of human colon cancer DLD-1 xenografts in nude mice, as compared to the untreated control (P < 0.01, n = 10).

CONCLUSION

Our data suggest that PEGylation improved the bioavailability of Gn as well as achieved tumor-targeted delivery and controlled release of Gn, which enhanced its overall biocompatibility and drug efficacy in vivo. This provides proof of concept for the development of Gn-lip as a molecular therapy for colon cancer with MSI1/MSI2 overexpression.

Gemcitabine enhances cell invasion via activating HAb18G/CD147-EGFR-pSTAT3 signaling

Pancreatic cancer, one of the most lethal cancers, has very poor 5-year survival partly due to gemcitabine resistance. Recently, it was reported that chemotherapeutic agents may act as stressors to induce adaptive responses and to promote chemoresistance in cancer cells. During long-term drug treatment, the minority of cancer cells survive and acquire an epithelial-mesenchymal transition phenotype with increased chemo-resistance and metastasis. However, the short-term response of most cancer cells remains unclear. This study aimed to investigate the short-term response of pancreatic cancer cells to gemcitabine stress and to explore the corresponding mechanism. Our results showed that gemcitabine treatment for 24 hours enhanced pancreatic cancer cell invasion. In gemcitabine-treated cells, HAb18G/CD147 was up-regulated; and HAb18G/CD147 down-regulation or inhibition attenuated gemcitabine-enhanced invasion. Mechanistically, HAb18G/CD147 promoted gemcitabine-enhanced invasion by activating the EGFR (epidermal growth factor receptor)-STAT3 (signal transducer and activator of transcription 3) signaling pathway. Inhibition of EGFR-STAT3 signaling counteracted gemcitabine-enhanced invasion, and which relied on HAb18G/CD147 levels. In pancreatic cancer tissues, EGFR was highly expressed and positively correlated with HAb18G/CD147. These data indicate that pancreatic cancer cells enhance cell invasion via activating HAb18G/CD147-EGFR-pSTAT3 signaling. Our findings suggest that inhibiting HAb18G/CD147 is a potential strategy for overcoming drug stress-associated resistance in pancreatic cancer.

Expression of proteins associated with epithelial-mesenchymal transition in esophageal squamous cell carcinoma

Cluster of differentiation 147 (CD147), pituitary tumor transforming gene (PTTG) and CD44v6 are proteins involved in the epithelial-mesenchymal transition (EMT). To investigate the prognostic value of CD147 and PTTG, and CD44v6 expression in esophageal squamous cell carcinoma (ESCC), tissue microarray specimens from 76 patients with ESCC were evaluated by immunohistochemistry staining and scored by intensity and proportion of positive areas. Expression levels of CD147, PTTG and CD44v6 were higher in tumor tissues than in matched adjacent tissues. CD147 expression was positively associated with lymph node metastasis (P=0.025) and American Joint Committee on Cancer (AJCC) system clinical grades (P=0.037). CD147 expression was positively correlated with the expression levels of PTTG (R=0.369; P=0.001) and CD44v6 (R=0.320; P=0.005). In addition, Kaplan-Meier analysis indicated that positive expression of CD147, PTTG and CD44v6 was significantly associated with poor overall survival times (P=0.045, P=0.014 and P=0.027, respectively). Patients exhibiting CD147-PTTG co-expression, CD147-CD44v6 co-expression and CD147-PTTG-CD44v6 triple-positive expression had the poorest overall survival rates. In conclusion, the expression of EMT-associated proteins, including CD147, PTTG and CD44v6, was significantly associated with poor survival in ESCC and these novel targets may serve as potential biomarkers for anticancer therapies.

Overcoming chemo/radio-resistance of pancreatic cancer by inhibiting STAT3 signaling

Chemo/radio-therapy resistance to the deadly pancreatic cancer is mainly due to the failure to kill pancreatic cancer stem cells (CSCs). Signal transducer and activator of transcription 3 (STAT3) is activated in pancreatic CSCs and, therefore, may be a valid target for overcoming therapeutic resistance. Here we investigated the potential of STAT3 inhibition in sensitizing pancreatic cancer to chemo/radio-therapy. We found that the levels of nuclear pSTAT3 in pancreatic cancer correlated with advanced tumor grade and poor patient outcome. Liposomal delivery of a STAT3 inhibitor FLLL32 (Lip-FLLL32) inhibited STAT3 phosphorylation and STAT3 target genes in pancreatic cancer cells and tumors. Consequently, Lip-FLLL32 suppressed pancreatic cancer cell growth, and exhibited synergetic effects with gemcitabine and radiation treatment in vitro and in vivo. Furthermore, Lip-FLLL32 reduced ALDH1-positive CSC population and modulated several potential stem cell markers. These results demonstrate that Lip-FLLL32 suppresses pancreatic tumor growth and sensitizes pancreatic cancer cells to radiotherapy through inhibition of CSCs in a STAT3-dependent manner. By targeting pancreatic CSCs, Lip-FLLL32 provides a novel strategy for pancreatic cancer therapy via overcoming radioresistance.

Cancer stem cell markers in patterning differentiation and in prognosis of oral squamous cell carcinoma

Differentiation is a major histological parameter determining tumor aggressiveness and prognosis of the patient; cancer stem cells with their slow dividing and undifferentiated nature might be one of the factors determining the same. This study aims to correlate cancer stem cell markers (CD44 and CD147) with tumor differentiation and evaluate their subsequent effect on prognosis. Immunohistochemical analysis in treatment naïve oral cancer patients (n = 53) indicated that the expression of CD147 was associated with poorly differentiated squamous cell carcinoma and moderately differentiated squamous cell carcinoma (p < 0.01). Furthermore, co-expression analysis showed that 45% each of moderately differentiated squamous cell carcinoma and poorly differentiated squamous cell carcinoma patients were CD44^high/CD147^high as compared to only 10% of patients with well-differentiated squamous cell carcinoma. A three-way analysis indicated that differentiation correlated with recurrence and survival (p < 0.05) in only the patients with CD44^high/CD147^high cohort. Subsequently, relevance of these cancer stem cell markers in patterning the differentiation characteristics was evaluated in oral squamous cell carcinoma cell lines originating from different grades of oral cancer. Flowcytometry-based analysis indicated an increase in CD44⁺/CD147⁺ cells in cell lines of poorly differentiated squamous cell carcinoma (94.35 ± 1.14%, p < 0.001) and moderately differentiated squamous cell carcinoma origin (93.49 ± 0.47%, p < 0.001) as compared to cell line of well-differentiated squamous cell carcinoma origin (23.12% ± 0.49%). Expression profiling indicated higher expression of cancer stem cell and epithelial-mesenchymal transition markers in SCC029B (poorly differentiated squamous cell carcinoma originated; p ≤ 0.001), which was further translated into increased spheroid formation, migration, and invasion (p < 0.001) as compared to cell line of well-differentiated squamous cell carcinoma origin. This study suggests that CD44 and CD147 together improve the prognostic efficacy of tumor differentiation; in vitro results further point out that these markers might be determinant of differentiation characteristics, imparting properties of increased self-renewal, migration, and invasion.

TIP30 regulates lipid metabolism in hepatocellular carcinoma by regulating SREBP1 through the Akt/mTOR signaling pathway

Lipid reprogramming has been considered as a crucial characteristic in hepatocellular carcinoma (HCC) initiation and progression. However, detailed molecular mechanisms have yet to be clearly defined. Here, we examined the effects of tumor suppressor TIP30 on the regulation of HCC lipid metabolism. We found that decreased TIP30 expression leads to elevated fatty acid synthesis and enhanced levels of lipogenic enzymes SCD and FASN in HCC cells. Moreover, SREBP1 is one of the key transcription factors regulating liver lipid metabolism, and TIP30 deficiency significantly increased SREBP1 expression and nuclear accumulation. Small interfering RNAs targeting SREBP1 could reverse fatty acid synthesis induced by TIP30 deficiency. Furthermore, downregulating TIP30 activated the Akt/mTOR signaling pathway to upregulate SREBP1 expression, which promoted lipid metabolism by activating gene transcription of lipogenesis, including fasn and scd. We also showed that TIP30 deficiency-regulated lipid metabolism promoted proliferation of HCC cells. Clinically, our data revealed that TIP30 expression significantly correlated with SREBP1 in patients with HCC and that a combination of TIP30 and SREBP1 is a powerful predictor of HCC prognosis. Together, our data suggested a novel function of TIP30 in HCC progression and indicate that TIP30 regulation of SREBP1 may represent a novel target for HCC treatment.

Surgery combined with local 5-aminolevulinic acid-photodynamic therapy on skin cancer and its effect on the expression of cyclophilin A, cyclophilin B and CD147

The study evaluated an approach to treat skin cancer using surgery combined with local 5-aminolevulinic acid-photodynamic therapy (ALA-PDT). Seventy-six patients with skin cancer who were admitted to the Liaocheng People's Hospital from May 2014 to April 2015 were randomly divided into a control and an observation group (38 cases in each). The patients in the control group were treated with ALA-PDT alone. Those in the observation group were first subjected to surgical treatment, and then treated with ALA-PDT. The treatment efficacies of the two groups were compared. The expression of cancer markers CyPA, CyPB and CD147 were detected by immunohistochemical methods before and after the treatment. Our results showed the average healing time of the wounds of patients in the observation group was shorter, the number of treatments needed was less, the efficacy rate and the lesion appearance satisfaction were significantly higher, and the recurrence rate at 12 months after treatment and the incidence of adverse reactions were both significantly lower. Additionally, the levels of CyPA, CyPB and CD147 were reduced to a significantly higher degree after treatment in the observation group. No difference was found in the recurrence rate between the two groups at 6 months after treatment. We conclude that surgery combined with ALA-PDT is a safe and reliable treatment method, which can increase the survival rate while improving the recovery rate and appearance satisfaction in patients with skin cancer.

A novel small-molecule compound targeting CD147 inhibits the motility and invasion of hepatocellular carcinoma cells

CD147, a type I transmembrane glycoprotein, is highly expressed in various cancer types and plays important roles in tumor progression, especially by promoting the motility and invasion of hepatocellular carcinoma (HCC) cells. These crucial roles make CD147 an attractive target for therapeutic intervention in HCC, but no small-molecule inhibitors of CD147 have been developed to date. To identify a candidate inhibitor, we used a pharmacophore model derived from the structure of CD147 to virtually screen over 300,000 compounds. The 100 highest-ranked compounds were subjected to biological assays, and the most potent one, dubbed AC-73 (ID number: AN-465/42834501), was studied further. We confirmed that AC-73 targeted CD147 and further demonstrated it can specifically disrupt CD147 dimerization. Moreover, molecular docking and mutagenesis experiments showed that the possible binding sites of AC-73 on CD147 included Glu64 and Glu73 in the N-terminal IgC2 domain, which two residues are located in the dimer interface of CD147. Functional assays revealed that AC-73 inhibited the motility and invasion of typical HCC cells, but not HCC cells that lacked the CD147 gene, demonstrating on-target action. Further, AC-73 reduced HCC metastasis by suppressing matrix metalloproteinase (MMP)-2 via down-regulation of the CD147/ERK1/2/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Finally, AC-73 attenuated progression in an orthotopic nude mouse model of liver metastasis, suggesting that AC-73 or its derivatives have potential for use in HCC intervention. We conclude that the novel small-molecule inhibitor AC-73 inhibits HCC mobility and invasion, probably by disrupting CD147 dimerization and thereby mainly suppressing the CD147/ERK1/2/STAT3/MMP-2 pathways, which are crucial for cancer progression.

EMMPRIN Inhibits bFGF-Induced IL-6 Secretion in an Osteoblastic Cell Line, MC3T3-E1

Background: Electrolytically-generated acid functional water (FW) is obtained by electrolyzing low concentrations of saline. Although it has been widely used in clinical practice with various purposes, the underlying mechanisms of action involved have not been fully elucidated so far. We used the human cervical cancer-derived fibroblastic cell line (HeLa), to examine the cytokine secretion profile following FW treatment in the present study. Results: FW stimulation significantly induced the secretion of basic fibroblast growth factor (bFGF) and extracellular matrix metalloproteinase inducer (EMMPRIN). The effect of both factors on osteoblast-like MC3T3-E1 cells was further examined by stimulating the cells with the conditioned medium of FW-stimulated HeLa cells. However, the conditioned medium failed to induce IL-6 secretion. The MC3T3-E1 cells were further stimulated with recombinant bFGF or EMMPRIN or a combination of both factors. Intriguingly, bFGF-stimulated IL-6 induction was totally inhibited by EMMPRIN. Pretreatment with the specific inhibitor of nuclear factor-kappa B (NF-κB) drastically inhibited IL-6 secretion indicating that bFGF-induced IL-6 expression was dependent on NF-κB activation. The phosphorylation status of NF-κB p65 subunit was further examined. The results indicated that EMMPRIN inhibited bFGF-induced NF-κB p65 phosphorylation. Conclusions: These findings suggest that bFGF can induce IL-6 secretion in MC3T3-E1 cells through NF-κB activation. As EMMPRIN inhibited bFGF-induced IL-6 secretion by reducing the p65 subunit phosphorylation, it might be concluded that bFGF and EMMPRIN crosstalk in their respective signaling pathways.

Anti-Cancer Stem-like Cell Compounds in Clinical Development - An Overview and Critical Appraisal

Cancer stem-like cells (CSC) represent a subpopulation of tumor cells with elevated tumor-initiating potential. Upon differentiation, they replenish the bulk of the tumor cell population. Enhanced tumor-forming capacity, resistance to antitumor drugs, and metastasis-forming potential are the hallmark traits of CSCs. Given these properties, it is not surprising that CSCs have become a therapeutic target of prime interest in drug discovery. In fact, over the last few years, an enormous number of articles describing compounds endowed with anti-CSC activities have been published. In the meanwhile, several of these compounds and also approaches that are not based on the use of pharmacologically active compounds (e.g., vaccination, radiotherapy) have progressed into clinical studies. This article gives an overview of these compounds, proposes a tentative classification, and describes their biological properties and their developmental stage. Eventually, we discuss the optimal clinical setting for these compounds, the need for biomarkers allowing patient selection, the redundancy of CSC signaling pathways and the utility of employing combinations of anti-CSC compounds and the therapeutic limitations posed by the plasticity of CSCs.

Hispidulin induces mitochondrial apoptosis in acute myeloid leukemia cells by targeting extracellular matrix metalloproteinase inducer

Acute myeloid leukemia (AML) represents a heterogeneous group of hematological neoplasms with marked heterogeneity in response to both standard therapy and survival. Hispidulin, a flavonoid compound that is anactive ingredient in the traditional Chinese medicinal herb Salvia plebeia R. Br, has recently been reported to have anantitumor effect against solid tumors in vitro and in vivo. The aim of the present study was to investigate the effects of hispidulin on the human leukemia cell line in vitro and the underlying mechanisms of its actions on these cells. Our results showed that hispidulin inhibits AML cell proliferation in a dose- and time-dependent manner, and induces cell apoptosis throughan intrinsic mitochondrial pathway. Our results also revealed that hispidulin treatment significantly inhibits extracellular matrix metalloproteinase inducer (EMMPRIN) expression in both tested AML cell lines in a dose-dependent manner, and that the overexpression of EMMPRIN protein markedly attenuates hispidulin-induced cell apoptosis. Furthermore, our results strongly indicated that the modulating effect of hispidulin on EMMPRIN is correlated with its inhibitory effect on both the Akt and STAT3 signaling pathways.

EMMPRIN-Targeted Magnetic Nanoparticles for In Vivo Visualization and Regression of Acute Myocardial Infarction

Inhibition of extracellular matrix (ECM) degradation may represent a mechanism for cardiac protection against ischemia. Extracellular matrix metalloproteinase inducer (EMMPRIN) is highly expressed in response to acute myocardial infarction (AMI), and induces activation of several matrix metalloproteinases (MMPs), including gelatinases MMP-2 and MMP-9. We targeted EMMPRIN with paramagnetic/fluorescent micellar nanoparticles conjugated with the EMMPRIN binding peptide AP-9 (NAP9), or an AP-9 scrambled peptide as a negative control (NAPSC). We found that NAP9 binds to endogenous EMMPRIN in cultured HL1 myocytes and in mouse hearts subjected to ischemia/reperfusion (IR). Injection of NAP9 at the time of or one day after IR, was enough to reduce progression of myocardial cell death when compared to Control and NAPSC injected mice (infarct size in NAP9 injected mice: 32%±6.59 vs Control: 46%±9.04 or NAPSC injected mice: 48%±7.64). In the same way, cardiac parameters were recovered to almost healthy levels (LVEF NAP9 63% ± 7.24 vs Control 42% ± 4.74 or NAPSC 39% ± 6.44), whereas ECM degradation was also reduced as shown by inhibition of MMP-2 and MMP-9 activation. Cardiac magnetic resonance (CMR) scans have shown a signal enhancement in the left ventricle of NAP9 injected mice with respect to non-injected, and to mice injected with NAPSC. A positive correlation between CMR enhancement and Evans-Blue/TTC staining of infarct size was calculated (R:0.65). Taken together, these results point to EMMPRIN targeted nanoparticles as a new approach to the mitigation of ischemic/reperfusion injury.

Cytoplasmic EpCAM over-expression is associated with favorable clinical outcomes in pancreatic cancer patients with Hepatitis B virus negative infection

The identification of reliable prognostic markers that distinguish patients' status and predict therapeutic response can improve the clinical outcomes of pancreatic cancer patients. The epithelial cell adhesion molecule (EpCAM) is known to be highly expressed in cancers and serves as a prognosis factor. Generally, membranous EpCAM expression in cancer cells and its clinical significance are evaluated. However, there is also an evidence of cytoplasmic EpCAM distribution in cancer cells. Hence, we investigated which kind of the immunostaining pattern in pancreatic cancer patients was, and whether membranous or cytoplasmic immunostaining had clinical significance. We determined the cytoplasmic or membranous EpCAM expression by a well-established immunohistochemical staining protocol in 157 pairs of carcinoma and paired adjacent non-tumor pancreatic tissue samples using the EpCAM-specific antibody. Furthermore, we evaluated the relationship between tumoral EpCAM expression of resected specimens and patient's overall survival as well as other biological variables like clinical prognosis by Kaplan-Meier method and χ(2) test. We found that pancreatic cancer patients had expressed higher level of cytoplasmic EpCAM but lower level of membranous EpCAM, and their expressions were significantly correlated. Cytoplasmic EpCAM acted as a favorable prognosis factor on survival time in patients with HBV negative infection. Pancreatic cancer patients with cytoplasmic EpCAM over-expression and negative Hepatitis B virus infection might benefit further from post-surgery chemotherapy. These data suggested a potential role of cytoplasmic EpCAM in predicting patient's prognosis and determining therapeutic strategy.

Prognostic Indications of Elevated MCT4 and CD147 across Cancer Types: A Meta-Analysis

Background. Metabolism in the tumor microenvironment can play a critical role in tumorigenesis and tumor aggression. Metabolic coupling may occur between tumor compartments; this phenomenon can be prognostically significant and may be conserved across tumor types. Monocarboxylate transporters (MCTs) play an integral role in cellular metabolism via lactate transport and have been implicated in metabolic synergy in tumors. The transporters MCT1 and MCT4 are regulated via expression of their chaperone, CD147. Methods. We conducted a meta-analysis of existing publications on the relationship between MCT1, MCT4, and CD147 expression and overall survival and disease-free survival in cancer, using hazard ratios derived via multivariate Cox regression analyses. Results. Increased MCT4 expressions in the tumor microenvironment, cancer cells, or stromal cells were all associated with decreased overall survival and decreased disease-free survival (p < 0.001 for all analyses). Increased CD147 expression in cancer cells was associated with decreased overall survival and disease-free survival (p < 0.0001 for both analyses). Few studies were available on MCT1 expression; MCT1 expression was not clearly associated with overall or disease-free survival. Conclusion. MCT4 and CD147 expression correlate with worse prognosis across many cancer types. These results warrant further investigation of these associations.

Feedback Activation of STAT3 as a Cancer Drug-Resistance Mechanism

Signal transducer and activator of transcription 3 (STAT3) plays crucial roles in several cellular processes such as cell proliferation and survival, and has been found to be aberrantly activated in many cancers. Much research has explored the leading mechanisms for regulating the STAT3 pathway and its role in promoting tumorigenesis. We focus here on recent evidence suggesting that feedback activation of STAT3 plays a prominent role in mediating drug resistance to a broad spectrum of targeted cancer therapies and chemotherapies. We highlight the potential of co-targeting STAT3 and its primary target to overcome drug resistance, and provide perspective on repurposing clinically approved drugs as STAT3 pathway inhibitors, in combination with the FDA-approved receptor tyrosine kinase (RTK) inhibitors, to improve clinical outcome of cancer treatment.

Natural product (-)-gossypol inhibits colon cancer cell growth by targeting RNA-binding protein Musashi-1

Musashi-1 (MSI1) is an RNA-binding protein that acts as a translation activator or repressor of target mRNAs. The best-characterized MSI1 target is Numb mRNA, whose encoded protein negatively regulates Notch signaling. Additional MSI1 targets include the mRNAs for the tumor suppressor protein APC that regulates Wnt signaling and the cyclin-dependent kinase inhibitor P21(WAF-1). We hypothesized that increased expression of NUMB, P21 and APC, through inhibition of MSI1 RNA-binding activity might be an effective way to simultaneously downregulate Wnt and Notch signaling, thus blocking the growth of a broad range of cancer cells. We used a fluorescence polarization assay to screen for small molecules that disrupt the binding of MSI1 to its consensus RNA binding site. One of the top hits was (-)-gossypol (Ki = 476 ± 273 nM), a natural product from cottonseed, known to have potent anti-tumor activity and which has recently completed Phase IIb clinical trials for prostate cancer. Surface plasmon resonance and nuclear magnetic resonance studies demonstrate a direct interaction of (-)-gossypol with the RNA binding pocket of MSI1. We further showed that (-)-gossypol reduces Notch/Wnt signaling in several colon cancer cell lines having high levels of MSI1, with reduced SURVIVIN expression and increased apoptosis/autophagy. Finally, we showed that orally administered (-)-gossypol inhibits colon cancer growth in a mouse xenograft model. Our study identifies (-)-gossypol as a potential small molecule inhibitor of MSI1-RNA interaction, and suggests that inhibition of MSI1's RNA binding activity may be an effective anti-cancer strategy.

The biological function and clinical utilization of CD147 in human diseases: a review of the current scientific literature

CD147 or EMMPRIN is a member of the immunoglobulin superfamily in humans. It is widely expressed in human tumors and plays a central role in the progression of many cancers by stimulating the secretion of matrix metalloproteinases (MMPs) and cytokines. CD147 regulates cell proliferation, apoptosis, and tumor cell migration, metastasis and differentiation, especially under hypoxic conditions. CD147 is also important to many organ systems. This review will provide a detailed overview of the discovery, characterization, molecular structure, diverse biological functions and regulatory mechanisms of CD147 in human physiological and pathological processes. In particular, recent studies have demonstrated the potential application of CD147 not only as a phenotypic marker of activated regulatory T cells but also as a potential diagnostic marker for early-stage disease. Moreover, CD147 is recognized as an effective therapeutic target for hepatocellular carcinoma (HCC) and other cancers, and exciting clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies.

HAb18G/CD147 is involved in TGF-β-induced epithelial-mesenchymal transition and hepatocellular carcinoma invasion

Epithelial-mesenchymal transition (EMT) induced by the transforming growth factor beta (TGF-β) is involved in hepatocarcinogenesis and hepatocellular carcinoma (HCC) metastasis. HAb18G/CD147, a member of the immunoglobulin family, plays an important role in tumor invasion and metastasis. HAb18G/CD147 promotes EMT of hepatocytes through TGF-β signaling and is transcriptionally regulated by Slug. We investigated the role of HAb18G/CD147 in TGF-β-induced EMT in HCC invasion. Two human HCC cell lines, SMMC-7721 and HepG2, were used to determine the role of HAb18G/CD147 in EMT. Upregulation of HAb18G/CD147 induced by the high doses of TGF-β1 in SMMC-7721 (5 ng/mL) and HepG2 cells (10 ng/mL) (P < 0.05). CD147 upregulation was coupled with upregulation of Snail1 and Slug. CD147 knockout significantly decreased the expression of N-cadherin and vimentin, and colony formation ability of SMMC-7721 cells. TGF-β1 enhanced the migration capacity of SMMC-7721 cells, which was markedly attenuated by CD147 knockdown. Thus, HAb18G/CD147 is involved in TGF-β-induced EMT and HCC invasion.

Concurrent CD44s and STAT3 expression in human clear cell renal cellular carcinoma and its impact on survival

Although CD44 was overexpressed and considered as a useful prognostic marker in renal cell carcinoma, the prognostic role of CD44s in clear cell renal cell carcinoma (ccRCC) remains controversial. Moreover, the correlation and prognostic significance of CD44s and its downstream signaling target pSTAT3 are unclear in ccRCC. In this study, 75 pairs of carcinoma and paired adjacent non-tumor renal tissue samples were collected from patients with localized ccRCC who underwent a nephrectomy. The expression levels of CD44s and pSTAT3 were analyzed using immunohistochemistry. Correlations between CD44s/pSTAT3 expression and clinical and pathological characteristics were determined using x(2) test, Kaplan-Meier analysis and Cox's proportional hazards model. We found that CD44s is highly expressed in 46.67% of tumor tissues, and its high expression was significantly associated with high tumor grade (P < 0.001), large tumor size (P = 0.009) and advanced T stage (P = 0.004). A strong correlation exists between high expression of CD44s and pSTAT3 (r = 0.4013, P = 0.0004). The joint over expression of CD44s and pSTAT3 was present in 42.66% of tumor specimens and had an additive negative impact on overall survival. Patients with CD44s(high)pSTAT3(high) expression had significantly poor survival as compared to patients with CD44s(low)pSTAT3(low) tumor expression (P = 0.024), though the concurrent overexpression of CD44s and pSTAT3 was not an independent prognostic factor for overall survival. Our data indicate that expression of both CD44s and pSTAT3 in ccRCC is associated with advanced tumor stage and patient survival. The conclusions from this study may improve the prediction of ccRCC prognosis information when CD44s and pSTAT3 expression are evaluated together with classical clinicopathological parameters.

Antibody against CD44s inhibits pancreatic tumor initiation and postradiation recurrence in mice

BACKGROUND & AIMS

CD44s is a surface marker of tumor-initiating cells (TICs); high tumor levels correlate with metastasis and recurrence, as well as poor outcomes for patients. Monoclonal antibodies against CD44s might eliminate TICs with minimal toxicity. This strategy is unclear for treatment of pancreatic cancer, and little is known about how anti-CD44s affect pancreatic cancer initiation or recurrence after radiotherapy.

METHODS

One hundred ninety-two pairs of human pancreatic adenocarcinoma and adjacent nontumor pancreatic tissues were collected from patients undergoing surgery. We measured CD44s levels in tissue samples and pancreatic cancer cell lines by immunohistochemistry, real-time polymerase chain reaction, and immunoblot; levels were correlated with patient survival times. We studied the effects of anti-CD44s in mice with human pancreatic tumor xenografts and used flow cytometry to determine the effects on TICs. Changes in CD44s signaling were examined by real-time polymerase chain reaction, immunoblot, reporter assay, and in vitro tumorsphere formation assays.

RESULTS

Levels of CD44s were significantly higher in pancreatic cancer than adjacent nontumor tissues. Patients whose tumors expressed high levels of CD44s had a median survival of 10 months compared with >43 months for those with low levels. Anti-CD44s reduced growth, metastasis, and postradiation recurrence of pancreatic xenograft tumors in mice. The antibody reduced the number of TICs in cultured pancreatic cancer cells and xenograft tumors, as well as their tumorigenicity. In cultured pancreatic cancer cell lines, anti-CD44s down-regulated the stem cell self-renewal genes Nanog, Sox-2, and Rex-1 and inhibited signal transducer and activator of transcription 3-mediated cell proliferation and survival signaling.

CONCLUSIONS

The TIC marker CD44s is up-regulated in human pancreatic tumors and associated with patient survival time. CD44s is required for initiation, growth, metastasis, and postradiation recurrence of xenograft tumors in mice. Anti-CD44s eliminated bulk tumor cells as well as TICs from the tumors. Strategies to target CD44s cab be developed to block pancreatic tumor formation and post-radiotherapy recurrence in patients.