Dicoumarol sensitizes renal cell carcinoma Caki cells to TRAIL-induced apoptosis through down-regulation of Bcl-2, Mcl-1 and c-FLIP in a NQO1-independent manner

Ring Finger Protein 34 (RNF34) as a Prognostic Biomarker for Clear Cell Renal Cell Carcinoma

INTRODUCTION

Ring finger proteins play pivotal roles in diverse cellular processes and are implicated in contribution to cancer. Ring finger protein 34 (RNF34) has antiapoptotic and oncogenic properties. RNF34 is upregulated during carcinogenesis and tumor progression in the colorectal adenoma-carcinoma sequence and was already described to mediate chemoresistance. In clear cell renal cell carcinoma (ccRCC), however, the role and expression patterns of RNF34 are unknown.

METHODS

First, we investigated the association of RNF34 mRNA expression with clinicopathological parameters and survival using data obtained from The Cancer Genome Atlas (TCGA) ccRCC cohort (N = 533). To assess RNA34 protein expression, we performed immunohistochemical (IHC) staining of an established ccRCC cohort (University of Bonn) in a tissue microarray (TMA) format. This validation cohort contains 109 primary ccRCC samples. IHC data were associated with clinicopathological parameters and overall survival (Kaplan-Meier analysis). Adjustment for covariables was done using the Cox regression model.

RESULTS

RNF34 expression is correlated with adverse clinicopathological parameters. Survival analysis revealed an association between RNF34 expression and shortened survival. Cox regression analysis confirmed RNF34 expression as an independent prognostic parameter.

CONCLUSION

Our study provides evidence for RNF34 as a prognostic biomarker in ccRCC and points toward a major role of this protein in renal cell carcinoma carcinogenesis.

Natural Compounds Derived from Plants on Prevention and Treatment of Renal Cell Carcinoma: A Literature Review

Renal cell carcinoma (RCC) accounts for roughly 85% of all malignant kidney cancer. Therapeutic options for RCC have expanded rapidly over the past decade. Targeted therapy and immunotherapy have ushered in a new era of the treatment of RCC, which has facilitated the outcomes of RCC. However, the related adverse effects and drug resistance remain an urgent issue. Natural compounds are optional strategies to reduce mobility. Natural compounds are favored by clinicians and researchers due to their good tolerance and low economic burden. Many studies have explored the anti-RCC activity of natural products and revealed relevant mechanisms. In this article, the chemoprevention and therapeutic potential of natural compounds is reviewed and the mechanisms regarding natural compounds are explored.

Dicoumarol: from chemistry to antitumor benefits

Dicoumarol, a coumarin-like compound, is known for its anticoagulant properties associated with the ability to inhibit vitamin K, being prescribed as a drug for several decades. The pharmaceutical value of dicoumarol turned it into a focus of chemists' attention, aiming its synthesis and of dicoumarol derivatives, bringing to light new methodologies. In recent years, several other bioactive effects have been claimed for dicoumarol and its derivatives, including anti-inflammatory, antimicrobial, antifungal, and anticancer, although the mechanisms of action underlying them are mostly not disclosed and additional research is needed to unravel them. This review presents a state of the art on the chemistry of dicoumarols, and their potential anticancer characteristics, highlighting the mechanisms of action elucidated so far. In parallel, we draw attention to the lack of in vivo studies and clinical trials to assess the safety and efficacy as drugs for later application.

Phytochemicals for the Prevention and Treatment of Renal Cell Carcinoma: Preclinical and Clinical Evidence and Molecular Mechanisms

Simple Summary

Renal cell carcinoma (RCC) is the most frequently diagnosed kidney cancer. Once RCC metastasizes, successful treatment is difficult to achieve. There is an apparent need for novel approaches to prevent and treat RCC. Phytochemicals are naturally derived compounds gaining increasing scientific interest due to their cancer preventive and chemotherapeutic properties. These phytochemicals have been shown to exhibit a multitude of anticancer effects against RCC. In this systematic review, we critically evaluate the potential these natural compounds possess for the prevention and treatment of RCC and discuss the future implications this may have in the fight against kidney cancer.

Abstract

Renal cell carcinoma (RCC) is associated with about 90% of renal malignancies, and its incidence is increasing globally. Plant-derived compounds have gained significant attention in the scientific community for their preventative and therapeutic effects on cancer. To evaluate the anticancer potential of phytocompounds for RCC, we compiled a comprehensive and systematic review of the available literature. Our work was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. The literature search was performed using scholarly databases such as PubMed, Scopus, and ScienceDirect and keywords such as renal cell carcinoma, phytochemicals, cancer, tumor, proliferation, apoptosis, prevention, treatment, in vitro, in vivo, and clinical studies. Based on in vitro results, various phytochemicals, such as phenolics, terpenoids, alkaloids, and sulfur-containing compounds, suppressed cell viability, proliferation and growth, showed cytotoxic activity, inhibited invasion and migration, and enhanced the efficacy of chemotherapeutic drugs in RCC. In various animal tumor models, phytochemicals suppressed renal tumor growth, reduced tumor size, and hindered angiogenesis and metastasis. The relevant antineoplastic mechanisms involved upregulation of caspases, reduction in cyclin activity, induction of cell cycle arrest and apoptosis via modulation of a plethora of cell signaling pathways. Clinical studies demonstrated a reduced risk for the development of kidney cancer and enhancement of the efficacy of chemotherapeutic drugs. Both preclinical and clinical studies displayed significant promise of utilizing phytochemicals for the prevention and treatment of RCC. Further research, confirming the mechanisms and regulatory pathways, along with randomized controlled trials, are needed to establish the use of phytochemicals in clinical practice.

Kidney cancer biomarkers and targets for therapeutics: survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, p53, KRAS and AKT in renal cell carcinoma

The incidence of renal cell carcinoma (RCC) is increasing worldwide with an approximate 20% mortality rate. The challenge in RCC is the therapy-resistance. Cancer resistance to treatment employs multiple mechanisms due to cancer heterogeneity with multiple genetic and epigenetic alterations. These changes include aberrant overexpression of (1) anticancer cell death proteins (e.g., survivin/BIRC5), (2) DNA repair regulators (e.g., ERCC6) and (3) efflux pump proteins (e.g., ABCG2/BCRP); mutations and/or deregulation of key (4) oncogenes (e.g., MDM2, KRAS) and/or (5) tumor suppressor genes (e.g., TP5/p53); and (6) deregulation of redox-sensitive regulators (e.g., HIF, NRF2). Foci of tumor cells that have these genetic alterations and/or deregulation possess survival advantages and are selected for survival during treatment. We will review the significance of survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, TP5/p53, KRAS and AKT in treatment resistance as the potential therapeutic biomarkers and/or targets in RCC in parallel with our analized RCC-relevant TCGA genetic results from each of these gene/protein molecules. We then present our data to show the anticancer drug FL118 modulation of these protein targets and RCC cell/tumor growth. Finally, we include additional data to show a promising FL118 analogue (FL496) for treating the specialized type 2 papillary RCC.

Dicoumarol suppresses HMGA2-mediated oncogenic capacities and inhibits cell proliferation by inducing apoptosis in colon cancer

Colon cancer is one of the leading causes of cancer-related deaths and its five-year survival rate remains low in locally advanced or metastatic stages of colon cancer. Overexpression of high mobility group protein AT-hook2 (HMGA2) is associated with cancer progression, metastasis, and poor prognosis in many malignancies. Oxidative stress regulates cellular mechanisms and provides an environment that favors the cancer cells to survive and progress, yet, at the same time, oxidative stress can also be utilized as a cancer-damaging strategy. The molecular regulatory roles of HMGA2 in oxidative stress and their involvement in cancer progression are largely unknown. In this study, we investigated the involvement of HMGA2 in regulation of oxidative stress responses by luciferase reporter assays. Moreover, we utilized dicoumarol (DIC), a derivative of coumarin which has been suggested to be involved in oxidation regulation with anticancer effects, and demonstrated that DIC could induce apoptosis and inhibit cell migration of HMGA2 overexpressing colon cancer cells. Further investigation also evidenced that DIC can enhance the cancer inhibition effect of 5-FU in colony formation assays. Taken together, our data revealed novel insights into the molecular mechanisms underlying HMGA2 and highlighted the possibility of targeting the cellular antioxidant system for treating patients and preventing from cancer progression in HMGA2 overexpressing colon cancer cells.

Isoforms S and L of MRPL33 from alternative splicing have isoform‑specific roles in the chemoresponse to epirubicin in gastric cancer cells via the PI3K/AKT signaling pathway

Drug resistance is a major cause of cancer-associated mortality. Epirubicin-based chemotherapy initially benefits patients with metastatic or advanced gastric cancer; however, tumor recurrence can occur following several courses of treatment. Mitochondrial ribosomal protein L33 (MRPL33)-long (L) and MRPL33-short (S), isoforms of MRPL33 that arise from AS, have been reported to regulate cell growth and apoptosis in cancer; however, few studies have evaluated the roles of MRPL33-L and MRPL33-S in gastric cancer. In the present study, MRPL33-L was demonstrated to be significantly more abundant in gastric tumor tissues than the MRPL33-S isoform. MRPL33-S promoted chemosensitivity to epirubicin in gastric cancer as demonstrated by a chemoresponse assay; chemosensitivity was suppressed in response to MRPL33-L. Gene microarray analysis was performed to investigate the underlying mechanisms. Bioinformatic analysis revealed that overexpression of MRPL33-L and MRPL33-S served critical roles in transcription, signal transduction and apoptosis. In particular, the phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) signaling pathway was markedly regulated. A total of 36 target genes, including PIK3 regulatory subunit α, AKT2, cAMP response element-binding protein (CREB) 1, forkhead box 3, glycogen synthase kinase 3β and mammalian target of rapamycin, which are involved in the PI3K/AKT signaling pathway, were selected for further investigation via protein-protein interaction network and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Furthermore, western blot analysis indicated that MRPL33-S promoted the chemoresponse to epirubicin by deactivating PI3K/AKT/CREB signaling and inducing apoptosis, while MRPL33-L had the opposite effects. In conclusion, the results of the present study revealed that isoforms S and L of MRPL33, which arise from alternative splicing, exhibited opposing roles in the chemoresponse to epirubicin in gastric cancer via the PI3K/AKT signaling pathway. These findings may contribute to the development of potential therapeutic strategies for the resensitization of patients with gastric cancer to epirubicin treatment.

A small compound spindlactone A sensitizes human endometrial cancer cells to TRAIL-induced apoptosis via the inhibition of NAD(P)H dehydrogenase quinone 1

Introduction

Spindlactone A (SPL-A) is a novel small molecule inhibitor of TACC3 that selectively inhibits the nucleation of centrosome microtubules and induces mitotic arrest in ovarian cancer cells. SPL-A is derived from dicoumarol which inhibits the activity of NAD(P)H dehydrogenase quinone oxidoreductase 1 (NQO1). This study aimed to investigate the mechanism by which SPL-A enhances TRAIL-induced apoptosis in endometrial carcinoma cells.

Materials and methods

Endometrial carcinoma cells were treated with SPL-A and/or TRAIL, and the apoptosis and protein expression in the treated cells were examined.

Results

Combined treatment with SPL-A and TRAIL significantly induced apoptosis in various human endometrial carcinoma cells, but not in normal human endometrial stromal cells and endometrial epithelial cells. Notably, both NQO1 inhibitor ES936 and NQO1 siRNA enhanced TRAIL-induced apoptosis of endometrial carcinoma cells. Furthermore, SPL-A downregulated the expression of c-FLIP, Bcl-2, Bcl-xl, and Mcl-1, while increasing p53 expression.

Conclusion

In particular, luciferase assay showed that SPL-A inhibited Bcl-2 promoter activity, and p53 inhibitor PFT-α could reverse the effect of SPL-A on Bcl-2 expression. Moreover, Bcl-2 overexpression inhibited the apoptosis induced by SPL-A and TRAIL. Taken together, our results suggest that SPL-A sensitizes endometrial cancer cells to TRAIL-induced apoptosis via the regulation of apoptosis-related proteins and the inhibition of NQO1 activity.

Linarin sensitizes tumor necrosis factor-related apoptosis (TRAIL)-induced ligand-triggered apoptosis in human glioma cells and in xenograft nude mice

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) is reported as a promising anti-cancer therapeutic agent. Nevertheless, a variety of cancer cells, including human malignant glioma cells, are resistant to TRAIL treatment, indicating that it is necessary to find effective strategies to overcome the TRAIL resistance. Linarin (LIN), a natural flavonoid compound in Flos Chrysanthemi Indici (FCI), has been exhibited to exert various pharmacological activities, including anti-cancer. Here in our study, we found that non-cytotoxic doses of LIN (5μM) dramatically potentiated TRAIL (80ng/ml)-induced cytotoxicity (52.36±1.58%) and apoptosis (68.50±1.23%) using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and flow cytometry assays, respectively, in human glioma cells of U87MG. Apoptosis was evidenced by enhanced cleavage of Caspase-8/-9/-3 and poly (ADP-ribose) polymerase (PARP), and reduced anti-apoptotic proteins, including B-cell leukemia/lymphoma 2 (Bcl-2), mantle cell lymphoma (Mcl)-1, and Survivin. Moreover, both intrinsic and extrinsic apoptosis pathways were included in apoptosis induced by LIN and TRAIL co-treatment, along with high release of Cyto-c into cytoplasm and enhancement of fas-associated protein with death domain (FADD), death-inducing signaling complex (DISC), death receptor 4 (DR) 4 and DR5, respectively. Reactive oxygen species (ROS) generation, up to 39.86±2.32%, was also highly triggered by TRAIL and LIN combinational treatment, which was accompanied with high phosphorylation of c-Jun-N-terminal kinase (JNK). In vivo, TRAIL and LIN double treatment significantly reduced the tumor growth using xenograft tumor model through inducing apoptosis. We demonstrated that combining LIN with TRAIL treatments might be effective against TRAIL-resistant glioma cells through inducing apoptosis regulated by ROS generation.

Dicumarol inhibits PDK1 and targets multiple malignant behaviors of ovarian cancer cells

Pyruvate dehydrogenase kinase 1 (PDK1) is overexpressed in ovarian cancer and thus is a promising anticancer therapeutic target. Our previous work suggests that coumarin compounds are potential inhibitors of PDKs. In this study, we used the ovarian cancer cell line SKOV3 as the model system and examined whether dicumarol (DIC), a coumarin compound, could inhibit ovarian cancer through targeting PDK1. We showed that DIC potently inhibited the kinase activity of PDK1, shifted the glucose metabolism from aerobic glycolysis to oxidative phosphorylation, generated a higher level of reactive oxygen species (ROS), attenuated the mitochondrial membrane potential (MMP), induced apoptosis, and reduced cell viability in vitro. The same phenotypes induced by DIC also were translated in vivo, leading to significant suppression of xenograft growth. This study not only identifies a novel inhibitor for PDK1, but it also reveals novel anticancer mechanisms of DIC and provides a promising anticancer therapy that targets the Warburg effect.

Thymoquinone induces apoptosis through downregulation of c-FLIP and Bcl-2 in renal carcinoma Caki cells

Renal carcinoma is a common and frequently fatal carcinoma occurring worldwide and death rates due to this carcinoma are increasing with time. In the present study, we investigated the potential of thymoquinone a natural compound to induce apoptosis in renal carcinoma Caki cells. Thymoquinone efficiently enhanced the apoptotic population of Caki cells in a dose-dependent manner. Moreover, thymoquinone-mediated apoptosis caused downregulation of c-FLIP and Bcl-2, the master regulators of the anti-apoptotic mechanism. However, we did not find any changes in mRNA expression level of c-FLIP, therefore; this regulation of c-FLIP was a result of post-translation modification by thymoquinone. In contrast, expression of the Bcl-2 protein was observed at both transcriptional and translational level. However, we also observed that thymoquinone enhanced the level of intracellular reactive oxygen species (ROS) in Caki cells, which resulted in reduction of mitochondrial membrane potential (MMP) and cytochrome c release into cytoplasm. Our results postulate that thymoquinone induces apoptosis through downregulating c-FLIP and Bcl-2 which can be utilized as a chemotherapeutic agent to treat renal carcinoma.