Ovatodiolide Targets β -Catenin Signaling in Suppressing Tumorigenesis and Overcoming Drug Resistance in Renal Cell Carcinoma

Interaction between Wnt/β-catenin signaling pathway and EMT pathway mediates the mechanism of sunitinib resistance in renal cell carcinoma

BACKGROUND

Targeted drugs are the main methods of RCC treatment. However, drug resistance is common in RCC patients, in-depth study of the drug-resistant mechanism is essential.

METHODS

We constructed sunitinib resistant and Twist overexpressed A498 cells, and studied its mechanisms in vitro and in vivo.

RESULTS

In cell research, we found that either sunitinib resistance or Twist overexpression can activate Wnt/β-catenin and EMT signaling pathway, and the sunitinib resistance may work through β-catenin/TWIST/TCF4 trimer. In zebrafish research, we confirmed the similarity of Twist overexpression and sunitinib resistance, and the promoting effect of Twist overexpression on drug resistance.

CONCLUSIONS

Sunitinib resistance and Twist overexpression can activate Wnt/β-catenin signaling pathway and EMT to promote the growth and metastasis of RCC cells.

Clinical Effect of Retroperitoneal Laparoscopic Radical Nephrectomy on Renal Cell Carcinoma, the Influence of Renal Function, and the Influencing Factors of Recurrence

Renal cell carcinoma is abbreviated as renal carcinoma, and its clinical symptoms are basically hematuria, lumbago, and abdomen bump. As people's lifestyles change, the incidence of renal carcinoma continues to rise due to factors such as smoking and obesity. At present, surgical treatment is mostly used in clinical practice. Traditional open radical nephrectomy (ORN) is one of the main methods for clinical treatment of renal carcinoma. However, due to its large wound and large amount of intraoperative blood loss, the renal function of patients after surgery is poor, which is not conducive to the postoperative recovery of patients. Retroperitoneal laparoscopic radical nephrectomy (RLRN) has been widely used in the surgical treatment of renal cancer due to its advantages of small wound, less bleeding, and rapid recovery. The purpose of this study was to investigate the efficacy of RLRN in the treatment of renal cancer patients and its effect on renal function and to analyze the related factors affecting postoperative recurrence of patients. We adopt ORN and RLRN, two kinds of treatment, in patients with renal cancer surgery way, contrast analysis of the two groups of operation time, intraoperative blood loss, postoperative intestinal function recovery time, drainage tube indwelling time, length of hospital stay, and other clinical indicators and renal function indexes and use the single factor analysis and multifactor analysis, the relevant factors that affect kidney cancer patients with postoperative recurrence. The results showed that, compared with ORN treatment, RLRN treatment of renal cancer patients has a short operation time, less trauma, quick recovery after surgery, and fewer complications and can effectively alleviate the renal function injury and the body's inflammatory response, which is worthy of promotion. Postoperative recurrence was related to age, tumor diameter, TNM stage, surgical method, and postoperative immunotherapy.

Advances in Renal Cell Carcinoma Drug Resistance Models

Renal cell carcinoma (RCC) is the most common form of kidney cancer. Systemic therapy is the preferred method to eliminate residual cancer cells after surgery and prolong the survival of patients with inoperable RCC. A variety of molecular targeted and immunological therapies have been developed to improve the survival rate and prognosis of RCC patients based on their chemotherapy-resistant properties. However, owing to tumor heterogeneity and drug resistance, targeted and immunological therapies lack complete and durable anti-tumor responses; therefore, understanding the mechanisms of systemic therapy resistance and improving clinical curative effects in the treatment of RCC remain challenging. In vitro models with traditional RCC cell lines or primary cell culture, as well as in vivo models with cell or patient-derived xenografts, are used to explore the drug resistance mechanisms of RCC and screen new targeted therapeutic drugs. Here, we review the established methods and applications of in vivo and in vitro RCC drug resistance models, with the aim of improving our understanding of its resistance mechanisms, increasing the efficacy of combination medications, and providing a theoretical foundation for the development and application of new drugs, drug screening, and treatment guidelines for RCC patients.

Identification of a Novel Theranostic Signature of Metabolic and Immune-Inflammatory Dysregulation in Myocardial Infarction, and the Potential Therapeutic Properties of Ovatodiolide, a Diterpenoid Derivative

Myocardial infarction (MI) is a multifactorial global disease, recognized as one of the leading causes of cardiovascular morbidity and mortality. Timely and correct diagnoses and effective treatments could significantly reduce incidence of complications and improve patient prognoses. In this study, seven unconventional differentially expressed genes (DEGs) (MAN2A2, TNFRSF12A, SPP1, CSNK1D, PLAUR, PFKFB3, and CXCL16, collectively termed the MTSCPPC signature) were identified through integrating DEGs from six MI microarray datasets. The pathological and theranostic roles of the MTSCPPC signature in MI were subsequently analyzed. We evaluated interactions of the MTSCPPC signature with ovatodiolide, a bioactive compound isolated from Anisomeles indica (L.) Kuntze, using in silico molecular docking tools and compared it to specific inhibitors of the members of the MTSCPPC signature. Single-cell transcriptomic analysis of the public databases revealed high expression levels of the MTSCPPC signature in immune cells of adult human hearts during an MI event. The MTSCPPC signature was significantly associated with the cytokine–cytokine receptor interactions, chemokine signaling, immune and inflammatory responses, and metabolic dysregulation in MI. Analysis of a micro (mi)RNA regulatory network of the MTSCPPC signature suggested post-transcriptional activation and the roles of miRNAs in the pathology of MI. Our molecular docking analysis suggested a higher potential for ovatodiolide to target MAN2A2, CSNK1D, and TNFRSF12A. Collectively, the results derived from the present study further advance our understanding of the complex regulatory mechanisms of MI and provide a potential MI theranostic signature with ovatodiolide as a therapeutic candidate.

Innovative Purification Method of Ovatodiolide from Anisomeles indica to Induce Apoptosis in Human Gastric Cancer Cells

Ovatodiolide (Ova), found in the plant Anisomeles indica (AI), has been reported to have an anti-proliferation effect in various cancer cells. However, little information is available regarding the anti-cancer effect of Ova in human gastric cancer cells. In this study, we investigated the inhibitory effects and the mechanisms of action responsible for these effects on human AGS cell lines from a newly developed purification technique for Ova from AI extract. Extract obtained at the optimum condition of 95% ethanol extraction of AI was sequentially partitioned by using different polarity solvents. Enriched content of Ova (35.9% purity) from the n-hexane fraction was then applied to the purification by using centrifugal partition chromatography (CPC) in a two-phase solvent system consisting of n-hexane:ethyl acetate:methanol:water (1.0:1.0:1.0:1.0, v/v/v/v) to reach purity over >95.0%. In evaluation of the anti-proliferation effect on AGS cells, Ova induced cell apoptosis with IC₅₀ values of 13.02 and 6.18 μM at 24 and 48 h, respectively, and arrested the cells at the G2/M phase. Quantification of Bax/Bcl2 mRNA expressions using qPCR showed a 2.5-fold increase in the Ova (5 μM)-treated cells at 48 h than in the control group. Specific protein expression data warrant further research to further confirm the proposed Ova-induced apoptotic pathway in AGS cells.

Identification of Cancer Hub Gene Signatures Associated with Immune-Suppressive Tumor Microenvironment and Ovatodiolide as a Potential Cancer Immunotherapeutic Agent

Despite the significant advancement in therapeutic strategies, breast, colorectal, gastric, lung, liver, and prostate cancers remain the most prevalent cancers in terms of incidence and mortality worldwide. The major causes ascribed to these burdens are lack of early diagnosis, high metastatic tendency, and drug resistance. Therefore, exploring reliable early diagnostic and prognostic biomarkers universal to most cancer types is a clinical emergency. Consequently, in the present study, the differentially expressed genes (DEGs) from the publicly available microarray datasets of six cancer types (liver, lung colorectal, gastric, prostate, and breast cancers), termed hub cancers, were analyzed to identify the universal DEGs, termed hub genes. Gene set enrichment analysis (GSEA) and KEGG mapping of the hub genes suggested their crucial involvement in the tumorigenic properties, including distant metastases, treatment failure, and survival prognosis. Notably, our results suggested high frequencies of genetic and epigenetic alterations of the DEGs in association with tumor staging, immune evasion, poor prognosis, and therapy resistance. Translationally, we intended to identify a drug candidate with the potential for targeting the hub genes. Using a molecular docking platform, we estimated that ovatodiolide, a bioactive anti-cancer phytochemical, has high binding affinities to the binding pockets of the hub genes. Collectively, our results suggested that the hub genes were associated with establishing an immune-suppressive tumor microenvironment favorable for disease progression and promising biomarkers for the early diagnosis and prognosis in multiple cancer types and could serve as potential druggable targets for ovatodiolide.

Immunohistochemical analysis of beta-catenin expression: a probable prognostic marker and potential therapeutic target in renal cell carcinoma

Background and aims

Renal cell carcinoma (RCC) seems to be the most aggressive type of genitourinary neoplasm. Down regulation of normal beta-catenin expression contributes to development of RCC, reflecting the role of beta-catenin/Wnt signaling pathway in pathogenesis. This study aims to evaluate the significance of beta-catenin expression and its correlation with the prognostic parameters.

Methods

A cross-sectional observational study was carried out in a tertiary care center on 58 RCC cases using variables like histological grade and type, tumor stage, necrosis. Formalin fixed, paraffin-embedded blocks were evaluated for beta-catenin expression by immunohistochemistry using scoring system. Data were analyzed by mean ± SD, χ² test, Pearson’s correlation test.

Results

Membranous score (MS) had a strong negative correlation with tumor stage (r=−0.407, p=0.044) and grade (r=−0.787, p=<0.001). Mean membranous score difference between low (Stage 1 and 2) vs. high stage (Stage 3 and 4) and low (Grade 1 and 2) vs. high grade (Grade 3 and 4) was statistically significant (p<0.001). Cytoplasmic score (CS) had positive correlation with tumor stage (r=0.586; p=0.002). No significant correlation was evident between cytoplasmic scores and tumor grade, however the mean cytoplasmic score difference between low grade vs. high grade was statistically significant (p < 0.001).

Conclusion

Beta-catenin may play a crucial role in the pathogenesis of RCC and has a positive correlation with the biological behavior of this tumor. The important role of beta-catenin as a prognostic parameter and probably a critical evaluator of targeted chemotherapy cannot be overemphasized.

Targeting Strategies for Renal Cancer Stem Cell Therapy

Renal cell carcinoma (RCC) is an intractable genitourinary malignancy that accounts for approximately 4% of adult malignancies. Currently, there is no approved targeted therapy for RCC that has yielded durable remissions, and they remain palliative in intent. Emerging evidence has indicated that renal tumorigenesis and RCC treatment-resistance may originate from renal cancer stem cells (CSCs) with tumor-initiating capacity (CSC hypothesis). A better understanding of the mechanism underlying renal CSCs will help to dissect RCC heterogeneity and drug treatment efficiency, to promote more personalized and targeted therapies. In this review, we summarized the stem cell characteristics of renal CSCs. We outlined the targeting strategies and challenges associated with developing therapies that target renal CSCs angiogenesis, immunosuppression, signaling pathways, surface biomarkers, microRNAs and nanomedicine. In conclusion, CSCs are an important role in renal carcinogenesis and represent a valid target for treatment of RCC patients.

Drug resistance in papillary RCC: from putative mechanisms to clinical practicalities

Papillary renal cell carcinoma (pRCC) is the second most common renal cell carcinoma (RCC) subtype and accounts for 10-15% of all RCCs. Despite clinical need, few pharmacogenomics studies in pRCC have been performed. Moreover, current research fails to adequately include pRCC laboratory models, such as the ACHN or Caki-2 pRCC cell lines. The molecular mechanisms involved in pRCC development and drug resistance are more diverse than in clear-cell RCC, in which inactivation of VHL occurs in the majority of tumours. Drug resistance to multiple therapies in pRCC occurs via genetic alteration (such as mutations resulting in abnormal receptor tyrosine kinase activation or RALBP1 inhibition), dysregulation of signalling pathways (such as GSK3β-EIF4EBP1, PI3K-AKT and the MAPK or interleukin signalling pathways), deregulation of cellular processes (such as resistance to apoptosis or epithelial-to-mesenchymal transition) and interactions between the cell and its environment (for example, through activation of matrix metalloproteinases). Improved understanding of resistance mechanisms will facilitate drug discovery and provide new effective therapies. Further studies on novel resistance biomarkers are needed to improve patient prognosis and stratification as well as drug development.

Embryonic Cul4b is important for epiblast growth and location of primitive streak layer cells

Cul4b-null (Cul4bΔ/Y) mice undergo growth arrest and degeneration during the early embryonic stages and die at E9.5. The pathogenic causes of this lethality remain incompletely characterized. However, it has been hypothesized that the loss of Cul4b function in extraembryonic tissues plays a key role. In this study, we investigated possible causes of death for Cul4b-null embryos, particularly in regard to the role of embryonic Cul4b. First, we show that the loss of embryonic Cul4b affects the growth of the inner cell mass in vitro and delays epiblast development during the gastrulation period at E6.5~E7.5 in vivo, as highlighted by the absence of the epiblastic transcription factor Brachyury from E6.5~E7.5. Additionally, at E7.5, strong and laterally expanded expression of Eomes and Fgf8 signaling was detected. Sectioning of these embryos showed disorganized primitive streak layer cells. Second, we observed that Mash2-expressing cells were present in the extraembryonic tissues of Cul4b-deficient embryos at E6.5 but were absent at E7.5. In addition, the loss of Cul4b resulted in decreased expression of cyclin proteins, which are required for the cell cycle transition from G1 to S. Taken together, these observations suggest that the embryonic expression of Cul4b is important for epiblast growth during E6.5~E7.5, and the loss of Cul4b results in either delayed growth of the epiblast or defective localization of primitive streak layer cells. As a result, the signaling activity mediated by the epiblast for subsequent ectoplacental cone development is affected, with the potential to induce growth retardation and lethality in Cul4bΔ/Y embryos.

A new macrocyclic diterpenoid from Anisomeles indica

A new macrocyclic diterpenoid, 4β,5β-dihydroxyovatodiolide (1), together with twenty-two known compounds (2-23) were isolated from the MeOH extract of the dried aerial parts of Anisomeles indica (L.) O. Kuntze (Labiatae). The structure of 1 was established on the basis of spectral evidence. Phenylethanoids, acteoside (5) and isoacteoside (6) showed significant inhibitory to IL-2 secretion of with respect to phorbol myristate acetate and anti-CD28 monoclonal antibody co-stimulated activation of human peripheral blood T cells.

Antibacterial activity of ovatodiolide isolated from Anisomeles indica against Helicobacter pylori

Helicobacter pylori infection is associated with high incidence of gastric diseases. The extensive therapy of H. pylori infection with antibiotics has increased its resistance rates worldwide. Ovatodiolide, a pure constituent isolated from Anisomeles indica, has been demonstrated to possess bactericidal activity against H. pylori. In this study, ovatodiolide inhibited the growth of both H. pylori reference strain and clinical multidrug-resistant isolates. Docking analysis revealed that ovatodiolide fits into the hydrophobic pocket of a ribosomal protein, RpsB. Furthermore, ovatodiolide inhibited bacterial growth by reducing levels of RpsB, which plays a crucial role in protein translation. Our results demonstrate that ovatodiolide binds to a ribosomal protein and interferes with protein synthesis. This study provides evidence that ovatodiolide has the potential to be developed into a potent therapeutic agent for treating H. pylori infection.

Investigation of ovatodiolide, a macrocyclic diterpenoid, as a potential inhibitor of oral cancer stem-like cells properties via the inhibition of the JAK2/STAT3/JARID1B signal circuit

BACKGROUND

The cancer stem cells (CSCs) have been shown to play key roles in the oral cancer initiation, distant metastasis, the development of chemoresistance and recurrence after treatment. Therefore, the inhibition of oral CSCs has been the target for therapeutic development.

PURPOSE

In this study, we investigated the anti-CSCs potential of Ovatodiolide (Ova), a diterpenoid isolate of Anisomeles indica, in vitro and in vivo.

METHODS

Oral CSCs were treated with Ova, and the expression of pluripotency factors Oct4, Sox-2, and Nanog were evaluated by western blot. Effect of Ova on self-renewal capacity and clonogenicity were assessed with the sphere formation and clonogenic assay in CSCs model derived from oral cancer cell. The effect of Ova was also investigated in a mouse xenograft model obtained by injecting nude mice with oral CSCs cells.

RESULTS

We demonstrated that Ova significantly and dose-dependently suppressed oral cancer cell viability and colony formation; Ova markedly inhibited the ALDH1 activities and reduced the CD44^high/ALDH^rich cell sub-population. Additionally, Ova suppressed orosphere formation by down-regulating CD133, Klf4, Oct4A, Nanog and JARID1B expression. Furthermore, Ova-mediated anti-cancer effects were associated with the dose-dependent reduction in the expression levels of STAT3, p-STAT3, pJAK2, pAKT and pERK1/2 protein. Moreover, Ova synergistically enhanced the anticancer effect of cisplatin against the SAS, FaDu, HSC-3 and TW2.6 orospheres. Ova significantly attenuated the tumor-initiating potential of orosphere in mouse xegnograft model.

CONCLUSION

These results demonstrate that Ova effectively suppressed oral tumorigenesis and stemness properties via JAK2/STAT3 signaling. Ova may be considered for future clinical usage.

Downregulation of Cancer Stemness by Novel Diterpenoid Ovatodiolide Inhibits Hepatic Cancer Stem Cell-Like Traits by Repressing Wnt/[Formula: see text]-Catenin Signaling

The hierarchical tumor propagation or cancer stem cells (CSCs) model of carcinogenesis postulates that like physiologic adult stem cell (ASC), the CSCs positioned at the apex of any tumor population form the crux of tumor evolution with a constitutive regenerative capacity and differentiation potential. The propagation and recurrence of the characteristically heterogeneous and therapy-resistant hepatocellular carcinoma (HCC), adds to accumulating evidence to support this CSCs model. Based on the multi-etiologic basis of HCC formation which among others, focuses on the disruption of the canonical Wnt signaling pathway, this study evaluated the role of cembrane-type phytochemical, Ovatodiolide, in the modulation of the Wnt/[Formula: see text]-catenin pathway, and its subsequent effect on liver CSCs' activities. Our fluorescence-activated cell sorting (FACS) and quantitative RT-PCR analyses of side population (SP) indicated that CD133+ cells were [Formula: see text]-catenin-overexpressing, more aggressive, and resistant to the conventional anticancer agents, Cisplatin and Doxorubicin, when compared to [Formula: see text]-catenin-downregulated group. We demonstrated that marked upregulation of [Formula: see text]-catenin and its downstream targets effectively enhanced hepatosphere formation, with an associated induction of CD133, OCT4 and Sox2 expression and also caused an significant enhancement of HCC proliferation. However, treatment with Ovatodiolide induced downregulation of [Formula: see text]-catenin and its downstream effector genes, abolished hepatosphere formation and reversed the [Formula: see text]-catenin-associated enhancement of HCC growth. In summary, we demonstrated for the first time that Ovatodiolide suppressed the canonical Wnt signaling pathway, and inhibited the generation of liver CSCs; Thus, projecting Ovatodiolide as a putatively effective therapeutic agent for anti-HCC target therapy.

Ovatodiolide suppresses yes-associated protein 1-modulated cancer stem cell phenotypes in highly malignant hepatocellular carcinoma and sensitizes cancer cells to chemotherapy in vitro

The cancer stem cells (CSCs) theory recently became a focus of heightened attention in cancer biology, with the proposition that CSCs may constitute an important therapeutic target for effective anticancer therapy, because of their demonstrated role in tumor initiation, chemo-, and radio-resistance. Liver CSCs are a small subpopulation of poorly- or undifferentiated liver tumor cells, implicated in tumorigenesis, metastasis, resistance to therapy and disease relapse, enriched with and associated with the functional markers corresponding to the CSCs-enriched side population (SP), high aldehyde dehydrogenase (ALDH) activity, and enhanced formation of in vitro liver CSCs models, referred to herein as hepatospheres. In this study, we found YAP1 was significantly expressed in the SP cells, as well as in generated hepatospheres compared to non-SP or parental HCC cells, at transcript and/or protein levels. In addition, downregulation of YAP1 expression levels by small molecule inhibitor and siRNA transfection, in the HCC cell lines, PLC/PRF/5 and Mahlavu, were associated with marked loss of ability to form hepatospheres and increased sensitivity to sorafenib. Consistent with the above, we demonstrated that YAP1 expression positively correlated with that of Sox2, Oct4, c-Myc and GRP78, markers of stemness and drug resistance. This is suggestive of YAP1's role as a modulator of cancer stemness, ER stress and chemoresistance. For the first time, we demonstrate that Ovatodiolide significantly attenuates YAP1 expression and subsequently suppressed YAP1-modulated CSCs phenotypes and associated disease progression, consistent with our previous finding in breast cancer. Taken together, our findings suggest that YAP1, highly expressed in malignant liver tumours, contributes to hepatocellular CSCs phenotype and is a molecular target of interest for CSCs targeted therapy in liver cancer patients.

The Challenges of Modeling Drug Resistance to Antiangiogenic Therapy

Drug resistance remains an ongoing challenge for the majority of patients treated with inhibitors of the vascular endothelial growth factor (VEGF) pathway, a key regulator of tumor angiogenesis. Preclinical models have played a significant role in identifying multiple complex mechanisms of antiangiogenic treatment failure. Yet questions remain about the optimal methodology to study resistance that may assist in making clinically relevant choices about alternative or combination treatment strategies. The origins of antiangiogenic treatment failure may stem from the tumor vasculature, the tumor itself, or both together, and preclinical methods that define resistance are diverse and rarely compared. We performed a literature search of the preclinical methodologies used to examine resistance to VEGF pathway inhibitors and identified 109 papers from more than 400 that use treatment failure as the starting point for mechanistic study. We found that definitions of resistance are broad and inconsistent, involve only a small number of reagents, and derive mostly from in vitro and in vivo methodologies that often do not represent clinically relevant disease stages or progression. Together, this literature analysis highlights the challenges of studying inhibitors of the tumor microenvironment in the preclinical setting and the need for improved methodology to assist in qualifying (and quantifying) treatment failure to identify mechanisms that will help predict alternative strategies in patients.

Ovatodiolide suppresses colon tumorigenesis and prevents polarization of M2 tumor-associated macrophages through YAP oncogenic pathways

Background

An increased expression of Yes-associated protein (YAP1) has been shown to promote tumorigenesis in many cancer types including colon. However, the role of YAP1 in promoting colon tumorigenesis remains unclear. Here, we demonstrate that YAP1 expression is associated with M2 tumor-associated macrophage polarization and the generation of colon cancer stem-like cells. YAP1 downregulation by gene silencing or a phytochemical, ovatodiolide, not only suppresses colon cancer tumorigenesis but also prevents M2 TAM polarization.

Methods

Human monocytic cells, THP-1, and colon cancer cell lines, HCT116 and DLD-1, were co-cultured to mimic the interactions between tumor and its microenvironment. M2 polarization of the THP-1 cells were examined using both flow cytometry and q-PCR technique. The inhibition of YAP1 signaling was achieved by gene-silencing technique or ovatodiolide. The molecular consequences of YAP1 inhibition was demonstrated via colony formation, migration, and colon-sphere formation assays. 5-FU and ovatodiolide were used in drug combination studies. Xenograft and syngeneic mouse models were used to investigate the role of YAP1 in colon tumorigenesis and TAM generation.

Results

An increased YAP1 expression was found to be associated with a poor prognosis in patients with colon cancer using bioinformatics approach. We showed an increased YAP1 expression in the colon spheres, and colon cancer cells co-cultured with M2 TAMs. YAP1-silencing led to the concomitant decreased expression of major oncogenic pathways including Kras, mTOR, β-catenin, and M2-promoting IL-4 and tumor-promoting IL-6 cytokines. TAM co-cultured colon spheres showed a significantly higher tumor-initiating ability in vivo. Ovatodiolide treatment alone and in combination with 5-FU significantly suppressed in vivo tumorigenesis and less TAM infiltration in CT26 syngeneic mouse model.

Conclusions

We have identified the dual function of YAP1 where its suppression not only inhibited tumorigenesis but also prevented the generation of cancer stem-like cells and M2 TAM polarization. Ovatodiolide treatment suppressed YAP1 oncogenic pathways to inhibit colon tumorigenesis and M2 TAM generation both in vitro and in vivo. Ovatodiolide should be considered for its potential for adjuvant therapeutic development.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0421-3) contains supplementary material, which is available to authorized users.

Wnt Signaling in Renal Cell Carcinoma

Renal cell carcinoma (RCC) accounts for 90% of all kidney cancers. Due to poor diagnosis, high resistance to the systemic therapies and the fact that most RCC cases occur sporadically, current research switched its focus on studying the molecular mechanisms underlying RCC. The aim is the discovery of new effective and less toxic anti-cancer drugs and novel diagnostic markers. Besides the PI3K/Akt/mTOR, HGF/Met and VHL/hypoxia cellular signaling pathways, the involvement of the Wnt/β-catenin pathway in RCC is commonly studied. Wnt signaling and its targeted genes are known to actively participate in different biological processes during embryonic development and renal cancer. Recently, studies have shown that targeting this pathway by alternating/inhibiting its intracellular signal transduction can reduce cancer cells viability and inhibit their growth. The targets and drugs identified show promising potential to serve as novel RCC therapeutics and prognostic markers. This review aims to summarize the current status quo regarding recent research on RCC focusing on the involvement of the Wnt/β-catenin pathway and how its understanding could facilitate the identification of potential therapeutic targets, new drugs and diagnostic biomarkers.

Ovatodiolide Inhibits Breast Cancer Stem/Progenitor Cells through SMURF2-Mediated Downregulation of Hsp27

Cancer stem/progenitor cells (CSCs) are a subpopulation of cancer cells involved in tumor initiation, resistance to therapy and metastasis. Targeting CSCs has been considered as the key for successful cancer therapy. Ovatodiolide (Ova) is a macrocyclic diterpenoid compound isolated from Anisomeles indica (L.) Kuntze with anti-cancer activity. Here we used two human breast cancer cell lines (AS-B145 and BT-474) to examine the effect of Ova on breast CSCs. We first discovered that Ova displayed an anti-proliferation activity in these two breast cancer cells. Ova also inhibited the self-renewal capability of breast CSCs (BCSCs) which was determined by mammosphere assay. Ova dose-dependently downregulated the expression of stemness genes, octamer-binding transcription factor 4 (Oct4) and Nanog, as well as heat shock protein 27 (Hsp27), but upregulated SMAD ubiquitin regulatory factor 2 (SMURF2) in mammosphere cells derived from AS-B145 or BT-474. Overexpression of Hsp27 or knockdown of SMURF2 in AS-B145 cells diminished the therapeutic effect of ovatodiolide in the suppression of mammosphere formation. In summary, our data reveal that Ova displays an anti-CSC activity through SMURF2-mediated downregulation of Hsp27. Ova could be further developed as an anti-CSC agent in the treatment of breast cancer.

MSK1-Mediated β-Catenin Phosphorylation Confers Resistance to PI3K/mTOR Inhibitors in Glioblastoma

Glioblastoma (GBM) represents a compelling disease for kinase inhibitor therapy because most of these tumors harbor genetic alterations that result in aberrant activation of growth factor-signaling pathways. The PI3K/mammalian target of the rapamycin (mTOR) pathway is dysregulated in over 50% of human GBM but remains a challenging clinical target. Inhibitors against PI3K/mTOR mediators have limited clinical efficacy as single agents. We investigated potential bypass mechanisms to PI3K/mTOR inhibition using gene expression profiling before and after PI3K inhibitor treatment by Affymetrix microarrays. Mitogen- and stress-activated protein kinase 1 (MSK1) was markedly induced after PI3K/mTOR inhibitor treatment and disruption of MSK1 by specific shRNAs attenuated resistance to PI3K/mTOR inhibitors in glioma-initiating cells (GIC). Further investigation showed that MSK1 phosphorylates β-catenin and regulates its nuclear translocation and transcriptional activity. The depletion of β-catenin potentiated PI3K/mTOR inhibitor-induced cytotoxicity and the inhibition of MSK1 synergized with PI3K/mTOR inhibitors to extend survival in an intracranial animal model and decreased phosphorylation of β-catenin at Ser(552) These observations suggest that MSK1/β-catenin signaling serves as an escape survival signal upon PI3K/mTOR inhibition and provides a strong rationale for the combined use of PI3K/mTOR and MSK1/β-catenin inhibition to induce lethal growth inhibition in human GBM. Mol Cancer Ther; 15(7); 1656-68. ©2016 AACR.

PubChem applications in drug discovery: a bibliometric analysis

A bibliometric analysis of PubChem applications is presented by reviewing 1132 research articles. The massive volume of chemical structure and bioactivity data in PubChem and its online services have been used globally in various fields including chemical biology, medicinal chemistry and informatics research. PubChem supports drug discovery in many aspects such as lead identification and optimization, compound-target profiling, polypharmacology studies and unknown chemical identity elucidation. PubChem has also become a valuable resource for developing secondary databases, informatics tools and web services. The growing PubChem resource with its public availability offers support and great opportunities for the interrogation of pharmacological mechanisms and the genetic basis of diseases, which are vital for drug innovation and repurposing.