Targeted Agents for the Treatment of Advanced Renal Cell Carcinoma

A novel immune-related lncRNA signature predicts the prognosis and immune landscape in ccRCC

BACKGROUND

As one of the most common tumors, the pathogenesis and progression of clear cell renal cell carcinoma (ccRCC) in the immune microenvironment are still unknown.

METHODS

The differentially expressed immune-related lncRNA (DEirlncRNA) was screened through co-expression analysis and the limma package of R, which based on the ccRCC project of the TCGA database. Then, we designed the risk model by irlncRNA pairs. In RCC patients, we have compared the area under the curve, calculated the Akaike Information Criterion (AIC) value of the 5-year receiver operating characteristic curve, determined the cut-off point, and established the optimal model for distinguishing the high-risk group from the low-risk group. We used the model for immune system assessment, immune point detection and drug sensitivity analysis after verifying the feasibility of the above model through clinical features.

RESULTS

In our study, 1541 irlncRNAs were included. 739 irlncRNAs were identified as DEirlncRNAs to construct irlncRNA pairs. Then, 38 candidate DEirlncRNA pairs were included in the best risk assessment model through improved LASSO regression analysis. As a result, we found that in addition to age and gender, T stage, M stage, N stage, grade and clinical stage are significantly related to risk. Moreover, univariate and multivariate Cox regression analysis results reveals that in addition to gender, age, grade, clinical stage and risk score are independent prognostic factors. The results show that patients in the high-risk group are positively correlated with tumor infiltrating immune cells when the above model is applied to the immune system. But they are negatively correlated with endothelial cells, macrophages M2, mast cell activation, and neutrophils. In addition, the risk model was positively correlated with overexpressed genes (CTLA, LAG3 and SETD2, P<0.05). Finally, risk models can also play as an important role in predicting the sensitivity of targeted drugs.

CONCLUSIONS

The new risk model may be a new method to predict the prognosis and immune status of ccRCC.

Integrated single-cell and bulk characterization of cuproptosis key regulator PDHB and association with tumor microenvironment infiltration in clear cell renal cell carcinoma

Background

Renal clear cell carcinoma (ccRCC) is one of the most prevalent cancers worldwide. Accumulating evidence revealed that copper-induced cell death played a vital role in various tumors. However, the underlying mechanism of cuproptosis with molecular heterogeneity and tumor microenvironment (TME) in ccRCC remains to be elucidated. The present study aimed to discover the biological function of cuproptosis regulators with the potential to guide clinical therapy.

Methods

Using Single-cell RNA-seq, bulk transcriptome and other multi-omics datasets, we identify essential cuproptosis-related hub gene PDHB for further study. The dysregulation of PDHB in ccRCC was characterized, together with survival outcomes, pathway enrichment and immune infiltration among tumor microenvironments. The functional significance and clinical association of PDHB was validated with loss of function experiments and surgical removal specimens.

Results

PDHB mRNA and protein expression level was significantly downregulated in ccRCC tissues compared with normal and paired normal tissues. Clinicopathological parameters and tissue microarray (TMA) indicated that PDHB was identified as a prognostic factor for survival outcomes among ccRCC patients. Additionally, low PDHB was negatively correlated with Treg cells, indicating an immunosuppressive microenvironment. Mechanistically, knockdown PDHB appeared to promote the RCC cells proliferation, migration, and invasion potentials. Subsequent studies showed that copper-induced cell death activation could overcome sunitinib resistance in RCC cells.

Conclusion

This research illustrated a cuproptosis-related hub gene PDHB which could serve as a potential prognostic marker and provide therapeutic benefits for clinical treatment of ccRCC patients.

SPTBN1 abrogates renal clear cell carcinoma progression via glycolysis reprogramming in a GPT2-dependent manner

BACKGROUND

Renal clear cell carcinoma (ccRCC) is the most prevalent tumors worldwide. Discovering effective biomarkers is essential to monitor the prognosis and provide alternative clinical options. SPTBN1 is implicated in various cancerous processes. However, its role in ccRCC remains unelucidated. This study intends to explore the biological function and mechanism of SPTBN1 in ccRCC.

METHODS

Single-cell and bulk RNA-seq, tissue microarray, real-time quantitative PCR, and western blotting were applied to verify the expression and predictive value of SPTBN1 in ccRCC. Gain or loss of functional ccRCC cell line models were constructed, and in vitro and in vivo assays were performed to elucidate its tumorigenic phenotypes. Actinomycin D experiment, RNA immunoprecipitation (RIP), specific inhibitors, and rescue experiments were carried out to define the molecular mechanisms.

RESULTS

SPTBN1 was down-regulated in ccRCC and knockdown of SPTBN1 displayed a remarkably oncogenic role both in vitro and in vivo; while overexpressing SPTBN1 reversed this effect. SPTBN1 mediated ccRCC progression via the pathway of glutamate pyruvate transaminase 2 (GPT2)-dependent glycolysis. The expression of GPT2 was significantly negatively correlated with that of SPTBN1. As an RNA binding protein SPTBN1, regulated the mRNA stability of GPT2.

CONCLUSION

Our research demonstrated that SPTBN1 is significantly down-regulated in ccRCC. SPTBN1 knockdown promotes ccRCC progression via activating GPT2-dependent glycolysis. SPTBN1 may serve as a therapeutic target for the treatment of ccRCC.

A regulatory circuit of lncRNA NLGN1-AS1 and Wnt signalling controls clear cell renal cell carcinoma phenotypes through FZD4-modulated pathways

BACKGROUND

Recent evidence has indicated that long non-coding RNAs (lncRNAs) were emerged as key molecules in clear cell renal cell carcinoma (ccRCC). TCGA database showed that the expression level of lncRNA NLGN1-AS1 was up-regulated in ccRCC; However, whether NLGN1-AS1 implicated in the malignant progression of ccRCC remained unclear.

METHODS

Based on TCGA database, candidate lncRNAs were selected and quantitative real-time PCR (qRT-PCR) was utilized to verify the expression levels of candidate lncRNAs in human ccRCC tissues. Loss-of-function experiments were performed to examine the biological functions of NLGN1-AS1 both in vitro and in vivo. According to bioinformatics analysis, fluorescence reporter assays and rescue experiments, the underlying mechanisms of NLGN1-AS1 in ccRCC cell lines were so clearly understood.

RESULTS

As a novel lncRNA, NLGN1-AS1 was up-regulated in ccRCC cell lines and associated with poor prognosis of and ccRCC patients, which was correlated with the progression of ccRCC. Functionally, the down-regulation of NLGN1-AS1 significantly decreased the proliferation of ccRCC cells both in vitro and in vivo. Bioinformatics analysis and luciferase report assays identified that miR-136-5p was a direct target of NLGN1-AS1. We also determined that FZD4 were inhibitory targets of miR-136-5p, and that Wnt/β-catenin signaling was inhibited by both NLGN1-AS1 knockdown and miR-136-5p over-expression. In addition, we found that the suppression of proliferation and the inhibition of Wnt/β-catenin pathway induced by NLGN1-AS1 knockdown would require the over-expression of FZD4.

CONCLUSIONS

Our findings suggested that lncRNA NLGN1-AS1 could promote the progression of ccRCC by targeting miR-136-5p/FZD4 and Wnt/β-catenin pathway, and might serve as a novel potential therapeutic target to inhibit the progression of ccRCC.

TRIM37 orchestrates renal cell carcinoma progression via histone H2A ubiquitination-dependent manner

Background

Ubiquitylation modification is one of the multiple post-transcriptional process to regulate cellular physiology, including cell signaling, cycle regulation, DNA repair and transcriptional regulation. Members of TRIM family proteins could be defined as E3 ubiquitin ligases as they contain a RING-finger domain, and alterations of TRIM proteins are involved into a broad range of diverse disorders including cancer. TRIM37 is a novel discovered E3 ubiquitin ligase and acts as a oncoprotein in multiple human neoplasms, however its biological role in RCC still remains elusive.

Methods

RCC microarray chips and public datasets were screened to identify novel TRIMs member as TRIM37, which was dysregulated in RCC. Gain or loss of functional cancer cell models were constructed, and in vitro and in vivo assays were performed to elucidate its tumorigenic phenotypes. Interactive network analyses were utilized to define intrinsic mechanism.

Results

We identified TRIM37 was upregulated in RCC tumors, and its aberrant function predicted aggressive neoplastic phenotypes, poorer survival endings. TRIM37 promoted RCC cells EMT and malignant progression via TGF-β1 signaling activation, as a consequence of directly mediated by ubiquitinating-H2A modifications.

Conclusions

Our findings identified a previously unappreciated role of TRIM37 in RCC progression and prognostic prediction. Importantly, we declared a novel ubiquitination-dependent link between TRIM ubiquitin ligases and TGF-β1 signaling in regulating cancerous malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01980-0.

Decreased expression of METTL14 predicts poor prognosis and construction of a prognostic signature for clear cell renal cell carcinoma

Background

METTL14, as one of N6-methyladenosine (m6A) related genes, has been found to be associated with promoting tumorigenesis in different types of cancers. This study was aimed to investigate the prognostic value of METTL14 in clear cell renal cell carcinoma (ccRCC).

Methods

We collected ccRCC patients’ clinicopathological parameters information and 13 m6A related genes expression from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analyses were conducted to investigate whether METTL14 could serve as an independent factor correlated with overall survival (OS). Gene Set Enrichment Analysis (GSEA) was carried out to identify METTL14-related signaling pathways. Moreover, a risk score (RS) was calculated to predict the prognosis of ccRCC. Quantitative real-time PCR (qRT-PCR) was also utilized to verify the expression of METTL14 in clinical specimens.

Results

Differently expressed m6A related genes were identified between ccRCC tissues and normal tissues. Therein, METTL14 was lowly expressed in ccRCC tissues and verified by qRT-PCR (all p < 0.01). Survival analysis indicated that high expression of METTL14 was associated with better OS (p = 1e−05). GSEA results revealed that high METTL14 expression was enriched in ERBB pathway, MAPK pathway, mTOR pathway, TGF-β pathway and Wnt pathway. Moreover, METTL14 was proved to be an independent prognostic factor by means of univariate and multivariate Cox regression analyses. Nomogram integrating both the METTL14 expression and clinicopathologic variables was also established to provide clinicians with a quantitative approach for predicting survival probabilities of ccRCC. Furthermore, a METTL14-based riskscore (RS) was developed with significant OS (p = 6.661e−16) and increased AUC of 0.856. Besides, significant correlated genes with METTL14 were also provided.

Conclusions

Our results indicated that METTL14 could serve as a favorable prognostic factor for ccRCC. Moreover, this study also provided a prognostic signature to predict prognosis of ccRCC and identified METTL14-related signaling pathways.

PTRF/CAVIN1, regulated by SHC1 through the EGFR pathway, is found in urine exosomes as a potential biomarker of ccRCC

Polymerase I and transcript release factor (PTRF)/Cavin1 regulates RNA polymerase I during transcription and plays a critical role in endocytosis. Abnormal expressions of PTRF were detected in multiple cancers according to increasing research. PTRF has been showed to involve in the formation and secretion of exosomes and can be detected in the exosomes, which suggests that PTRF would be a potential biomarker for diagnosis of clear cell renal cell carcinoma (ccRCC) using urine samples. Approximately 50-90% of ccRCC cases suffered abnormal epidermal growth factor receptor (EGFR), which activates a variety of signaling pathways, including the mitogen-activated protein kinase/extracellular signal-regulated kinase and Phosphoinositide 3-Kinase/Akt pathway. According to bioinformatic analysis of gene expression arrays of kidney clear cell carcinoma from The Cancer Genome Atlas, we found SHC1 was significantly overexpressed in high-grade ccRCC and correlated to poor prognosis, and also SHC1 was annotated in extracellular matrix process, which was regulated by EGFR. Further studies showed that the expression of PTRF was regulated by SHC1 through EGFR-Phosphoinositide 3-Kinase/Akt pathway. PTRF was detected in the exosomes isolated from ccRCC patients' urine and ccRCC cancer cells culture medium. It suggested that the abnormal SHC1-increased PTRF, which is detected in exosomes from urine, would be a potential marker for ccRCC diagnose and treatment.

DARS-AS1 promotes clear cell renal cell carcinoma by sequestering miR-194-5p to up-regulate DARS

Clear cell renal cell carcinoma (ccRCC), the most frequent subtype of renal cell carcinoma (RCC), is characterized by high relapse rate and mortality. Long non-coding RNAs (lncRNAs) are critical participants during cancer development. LncRNA DARS antisense RNA 1 (DARS-AS1), a newly-found lncRNA, is not specifically reported in ccRCC. However, Gene Expression Profiling Interactive Analysis (GEPIA) and starBase databases revealed the up-regulation of DARS-AS1 in ccRCC. Current study investigated the function and mechanism of DARS-AS1 in ccRCC. Functional assays including colony formation assay, EdU assay, caspase-3 activity detection, flow cytometry analysis and JC-1 assay were implemented to identify the role of DARS-AS1 in ccRCC. As a result, silencing of DARS-AS1 retarded proliferation and facilitated apoptosis in ccRCC cells. Moreover, mainly a cytoplasmic localization of lncRNA DARS-AS1 was verified in ccRCC cells. Then, we demonstrated that DARS-AS1 positively regulated its nearby gene, aspartyl-tRNA synthetase (DARS), by sequestering miR-194-5p. Moreover, DARS was testified as the oncogene in ccRCC and DARS-AS1 worked as a tumor-facilitator in ccRCC through miR-194-5p/DARS signaling. In a summary, this study firstly uncovered that DARS-AS1 boosted DARS expression via absorbing miR-194-5p, therefore contributing to malignancy in ccRCC. Our findings may be helpful for opening new strategies for ccRCC treatment.

Systematic investigation of the prognostic value of cell division cycle-associated proteins for clear cell renal cell carcinoma patients

Aim: To explore the prognostic value of the cell division cycle-associated proteins (CDCA) family in clear cell renal cell carcinoma. Methods: Gene profiles were collected from the The Cancer Genome Atlas-Kidney Renal Clear Cell Carcinoma (TCGA-KIRC), the GSE29609 and GSE22541 datasets. Genetic alteration and DNA methylation data were downloaded from the cBioPortal and MethSurv. The functional enrichment data were analyzed by Metascape. Results: The mRNA expression of the CDCAs, except CBX2, was significantly increased in clear cell renal cell carcinoma patients. Genetic alterations might affect the expression of CDCAs, but promotor methylation does not affect CDCA gene expression. The overall expression of the CDCAs, according to the The Cancer Genome Atlas-KIRC database (hazard ratio [HR]: 2.18), the GSE29609 (HR: 6.08) and GSE22541 (HR: 6.73), was significantly associated with unfavorable overall survival. In addition, genes co-expressed with CDCAs (R² ≥0.3) were highly associated with cell division and the FOXM1 pathway. Conclusion: Our study demonstrated that the aberrant expression of CDCA gene family members plays an indispensable role in tumorigenesis.

Targeting the TR4 nuclear receptor-mediated lncTASR/AXL signaling with tretinoin increases the sunitinib sensitivity to better suppress the RCC progression

Renal cell carcinoma (RCC) is one of the most lethal urological tumors. Using sunitinib to improve the survival has become the first-line therapy for metastatic RCC patients. However, the occurrence of sunitinib resistance in the clinical application has curtailed its efficacy. Here we found TR4 nuclear receptor might alter the sunitinib resistance to RCC via altering the TR4/lncTASR/AXL signaling. Mechanism dissection revealed that TR4 could modulate lncTASR (ENST00000600671.1) expression via transcriptional regulation, which might then increase AXL protein expression via enhancing the stability of AXL mRNA to increase the sunitinib resistance in RCC. Human clinical surveys also linked the expression of TR4, lncTASR, and AXL to the RCC survival, and results from multiple RCC cell lines revealed that targeting this newly identified TR4-mediated signaling with small molecules, including tretinoin, metformin, or TR4-shRNAs, all led to increase the sunitinib sensitivity to better suppress the RCC progression, and our preclinical study using the in vivo mouse model further proved tretinoin had a better synergistic effect to increase sunitinib sensitivity to suppress RCC progression. Future successful clinical trials may help in the development of a novel therapy to better suppress the RCC progression.

A positive feed-forward loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling promotes proliferation and metastasis of clear cell renal cell carcinoma

Background

The aberrant expression of long noncoding RNAs (lncRNAs) has recently emerged as key molecules in human cancers; however, whether lncRNAs are implicated in the progression of clear cell renal cell carcinoma (ccRCC) remains unclear.

Methods

Candidate lncRNAs were selected using microarray analysis and quantitative real-time PCR (qRT-PCR) was performed to detect lncRNAs expression in human ccRCC tissues. Overexpression and knocking down experiments in vivo and in vitro were performed to uncover the biological roles of lncRNA-URRCC on ccRCC cell proliferation and invasion. Microarray, chromatin immunoprecipitation, Luciferase reporter assay and western blot were constructed to investigate the molecular mechanisms underlying the functions of lncRNA-URRCC.

Results

The microarray analysis and qRT-PCR identified a new lncRNA, URRCC, whose expression is upregulated in RCC samples and associated with poor prognosis, leading to promote ccRCC cell proliferation and invasion. Mechanistically, URRCC enhances the expression of EGFL7 via mediating histone H3 acetylation of EGFL7 promoter, activation of P-AKT signaling, and suppressing P-AKT downstream gene, FOXO3. In return, FOXO3 could inhibit the transcription of URRCC via binding to the special region on the promoter of URRCC.

Conclusions

Our data suggests that targeting this newly identified feed-back loop between LncRNA-URRCC and EGFL7/P-AKT/FOXO3 signaling may enhance the efficacy of existing therapy and potentially imparts a new avenue to develop more potent therapeutic approaches to suppress RCC progression.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0998-y) contains supplementary material, which is available to authorized users.

Efficacy of sorafenib adjuvant therapy in northwestern Chinese patients with non-metastatic renal-cell carcinoma after nephrectomy: A multicenter retrospective study

Recent studies have confirmed the efficacy of sorafenib for patients with advanced renal cell carcinoma; however, its efficacy and safety as an adjuvant therapy in patients with non-metastatic and loco-regional renal cell carcinoma after surgery remains controversial. Thus, the aim of the present retrospective study was to evaluate the efficacy of adjuvant sorafenib therapy in such patients from 8 centers in northwestern China that were treated from August 2009 to December 2016.After surgery, the patients (n = 48) received oral sorafenib for 3 months. The control group (n = 48) comprised patients that underwent the same surgery from December 2009 to June 2016 but without adjuvant therapy who were matched 1:1 with the sorafenib group with respect to sex, age, pathological findings, disease stage and grade, operation time, and surgical procedure. The primary outcome compared between the groups was disease-free survival. Adverse events were also recorded to evaluate the safety of sorafenib. The influence of patients' characteristics and laboratory tests on recurrence was analyzed using unconditional logistic regression.Overall, the demographic characteristics of the 2 groups were similar. There was no significant difference in the rate of recurrence (8.3% for sorafenib patients and 6.2% for the matched patients, P = .66) or median disease-free survival between the 2 groups (hazard ratio = 1.561, 95% confidence interval = 0.349-6.987, P = .56). In multiple logistic regression analysis, increased blood urea nitrogen (BUN) emerged as an independent predictor of recurrence risk (P = .02).These results indicate that postoperative sorafenib adjuvant therapy did not achieve the expected beneficial effect, pointing to the need for further studies to evaluate its utility in such cases.

Infiltrating macrophages increase RCC epithelial mesenchymal transition (EMT) and stem cell-like populations via AKT and mTOR signaling

Infiltrating macrophages are a key component of inflammation during tumorigenesis and progression. However, the role of macrophages in renal cell carcinoma (RCC), especially in the stage of RCC malignant progression, is still unclear. Here, we found the macrophages could be recruited more easily into RCC tissues than the surrounding non-tumor tissues. In vitro co-culture system also confirmed RCC cells had a better capacity to recruit macrophages via CXCL8 signaling than normal renal epithelial cells. The consequences of recruiting more macrophages may then increase RCC cells invasion abilities. Mechanism dissection revealed that infiltrating macrophages could function through induction of epithelial-mesenchymal transition and increased cancer stem cell-like populations via activation of AKT/mTOR signal, and then led to increasing RCC cells invasion. The orthotopically xenografted mouse model with RCC cells and macrophages also confirmed that infiltrating macrophages could increase RCC cells progression via AKT/mTOR signal. Together, our results reveal a new mechanism that macrophages in the RCC tumor microenvironment could increase RCC metastasis via activation of the AKT/mTOR signals. Targeting this newly identified signaling may help us to better inhibit RCC metastasis.

LncRNA-SARCC suppresses renal cell carcinoma (RCC) progression via altering the androgen receptor(AR)/miRNA-143-3p signals

While the androgen receptor (AR) might promote renal cell carcinoma (RCC) initiation and progression, the molecular mechanisms involved remain largely unclear. Here, we discovered the novel LncRNA-SARCC, which was suppressed and associated with better prognosis in RCC. Preclinical studies using multiple RCC cells and in vivo mouse model indicated that LncRNA-SARCC could attenuate RCC cell invasion, migration and proliferation in vitro and in vivo. Mechanistically, LncRNA-SARCC bound and destabilized AR protein with an inhibition of AR function, which led to transcriptionally de-repress miR-143-3p expression, thus inhibition of its downstream signals including AKT, MMP-13, K-RAS and P-ERK. In addition, bisulfite sequencing analysis substantiated that LncRNA-SARCC promoter was highly methylated in renal cancer tissues compared with paired non-cancerous renal tissues. Notably, treating with Sunitinib, the multi-targeted receptor tyrosine kinase inhibitor, increased the expression of LncRNA-SARCC, which decreased RCC cells resistance to Sunitinib. Thus, our study presented a road map for targeting this newly identified LncRNA-SARCC and its pathway, which expands potential therapeutic strategies for RCC treatment.

Sulfonamide derivative targeting carbonic anhydrase IX as a nuclear imaging probe for colorectal cancer detection in vivo

Hypoxic microenvironment is a common situation in solid tumors. Carbonic anhydrase IX (CA9) is one of the reliable cellular biomarkers of hypoxia. The role of CA9 in colorectal cancer (CRC) remains to be clarified. CA9 inhibitor such as sulfonamides is known to block CA9 activation and reduce tumor growth consequently. Here, we aimed to investigate the CA9 expression in serum and tumor from different stages of CRC patients and utilize sulfonamide derivative with indium-111 labeling as a probe for CRC nuclear imaging detection in vivo. The serum CA9 was correlated with the tumor CA9 levels in different stages of CRC patients. Hypoxia increased cell viability and CA9 expression in colorectal cancer HCT-15 cells. Sulfonamide derivative 5-(2-aminoethyl)thiophene-2-sulfonamide (ATS) could bind with CA9 in vitro under hypoxia. Moreover, tumor tissues in HCT-15-induced xenograft mice possessed higher hypoxic fluorescence signal as compared with other organs. We also found that the radioisotope signal of indium-111 labeled ATS, which was utilized for CRC detection in HCT-15-induced xenograft mice, was markedly enhanced in tumors as compared with non-ATS control. Taken together, these findings suggest that CA9 is a potential hypoxic CRC biomarker and measurement of serum CA9 can be as a potential tool for diagnosing CA9 expressions in CRC clinical practice. The radioisotope-labeled sulfonamide derivative (ATS) may be useful to apply in CRC patients for nuclear medicine imaging.

The Histone Deacetylase Inhibitor Trichostatin A Sensitizes Human Renal Carcinoma Cells to TRAIL-Induced Apoptosis through Down-Regulation of c-FLIPL

Histone acetylation plays a critical role in the regulation of transcription by altering the structure of chromatin, and it may influence the resistance of some tumor cells to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) by regulating the gene expression of components of the TRAIL signaling pathway. In this study, we investigated the effects and molecular mechanisms of trichostatin A (TSA), a histone deacetylase inhibitor, in sensitizing TRAIL-induced apoptosis in Caki human renal carcinoma cells. Our results indicate that nontoxic concentrations of TSA substantially enhance TRAIL-induced apoptosis compared with treatment with either agent alone. Cotreatment with TSA and TRAIL effectively induced cleavage of Bid and loss of mitochondrial membrane potential (MMP), which was associated with the activation of caspases (-3, -8, and -9) and degradation of poly (ADP-ribose) polymerase (PARP), contributing toward the sensitization to TRAIL. Combined treatment with TSA and TRAIL significantly reduced the levels of the cellular Fas-associated death domain (FADD)-like interleukin-1β-converting enzyme (FLICE) inhibitory protein (c-FLIP), whereas those of death receptor (DR) 4, DR5, and FADD remained unchanged. The synergistic effect of TAS and TRAIL was perfectly attenuated in c-FLIP_L-overexpressing Caki cells. Taken together, the present study demonstrates that down-regulation of c-FLIP contributes to TSA-facilitated TRAIL-induced apoptosis, amplifying the death receptor, as well as mitochondria-mediated apoptotic signaling pathways.

Single nucleotide polymorphisms in the mitochondrial displacement loop and age-at-onset of renal cell carcinoma

The accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) has been described in various types of cancers, and their association with cancer risk and disease outcome has been extensively identified. In the present study, we investigated the association between age-at-onset and SNPs in the mitochondrial D-loop using a population-based series of renal cell carcinoma(RCC). The SNP sites of nucleotides 16293A/G were identified for their association with age-at-onset using the log-rank test. The age-at-onset of patients with the minor allele G genotype was significantly lower than that of patients with the A genotype at the 16293 site (p < 0.001). Genetic polymorphisms in the D-loop are predictive markers of age-at-onset in RCC patients. Accordingly, the analysis of genetic polymorphisms in the mitochondrial D-loop may help identify RCC patient subgroups at high risk of early onset.

Cytoreductive nephrectomy in metastatic renal cell carcinoma

Metastatic renal cell carcinoma is associated with a poor prognosis and a median survival time of only 6-12 months. However, the emergence of immunotherapies has rekindled interest in cytoreductive nephrectomy as a therapeutic option. Phase III randomized trials have demonstrated that cytoreductive nephrectomy significantly improves overall survival in selected patients with metastatic renal cell carcinoma treated with interferon immunotherapy. While cytokine-based immunotherapy may be considered the standard systemic therapy, clinical studies are ongoing to develop molecular biomarkers and new therapies with improved efficacy and tolerability. With further advances in our understanding of the pathogenesis, behavior and molecular biology of renal cell carcinoma, cytoreductive nephrectomy, in combination with molecular targeted therapies, may become the new standard of care for patients with metastatic renal cell carcinoma.

Kaempferol induces cell cycle arrest and apoptosis in renal cell carcinoma through EGFR/p38 signaling

Kaempferol has been shown to inhibit cell growth, induce apoptosis and cell cycle arrest in several tumors, but not in renal cell carcinoma (RCC). In the present study, we investigated the effects of kaempferol and the underlying mechanism(s) on the cell growth of RCC cells. MTT assay and colony formation assay were used to study cell growth, and flow cytometry was used to study apoptosis and cell cycles in different RCC cells treated with various doses of kaempferol. A significant inhibition on cell growth, induction of apoptosis and cell cycle arrest were observed in 786-O and 769-P cells after kaempferol treatment compared with the control group. Moreover, the results clearly showed that kaempferol causes a strong inhibition of the activation of the EGFR/p38 signaling pathways, upregulation of p21 expression and downregulation of cyclin B1 expression in human RCC cells, together with activation of PARP cleavages, induction of apoptotic death and inhibition of cell growth. Collectively, our results suggest that kaempferol may serve as a candidate for chemo-preventive or chemotherapeutic agents for RCC.

A phase 1b clinical trial of the multi-targeted tyrosine kinase inhibitor lenvatinib (E7080) in combination with everolimus for treatment of metastatic renal cell carcinoma (RCC)

Purpose

Lenvatinib is an oral multi-targeted tyrosine kinase inhibitor of VEGFR1-3, FGFR1-4, PDGFRβ, RET, and KIT. Everolimus is an oral mammalian target of rapamycin inhibitor approved for advanced renal cell carcinoma (RCC). This phase 1b study assessed safety, maximum tolerated dose (MTD), and preliminary antitumor activity of lenvatinib plus everolimus in metastatic RCC (mRCC) patients.

Methods

Patients with advanced unresectable or mRCC and Eastern Cooperative Oncology Group performance status 0–1 were eligible (number of prior treatments not restricted). Starting dose was lenvatinib 12 mg once daily with everolimus 5 mg once daily administered continuously in 28-day cycles using a conventional 3 + 3 dose-escalation design. At the MTD, additional patients were enrolled in an expansion cohort.

Results

Twenty patients (mean 58.4 years) received lenvatinib [12 mg (n = 7); 18 mg (n = 11); 24 mg (n = 2)] plus everolimus 5 mg. MTD was established as once daily lenvatinib 18 mg plus everolimus 5 mg. The most common treatment-related treatment-emergent adverse events (all dosing cohorts) were fatigue 60 % (Grade ≥3: 10 %), mucosal inflammation 50 %, proteinuria (Grade ≥3: 15 %), diarrhea (Grade ≥3: 10 %), vomiting (Grade ≥3: 5 %), hypertension, and nausea, each 40 %. In MTD and lowest-dose cohorts (n = 18), best responses of partial response and stable disease were achieved in 6 (33 %) and 9 (50 %) patients, respectively.

Conclusions

Lenvatinib 18 mg combined with everolimus 5 mg was associated with manageable toxicity consistent with individual agents and no new safety signals. Observed activity warrants further evaluation of the combination in advanced RCC patients.

Single nucleotide polymorphisms in the D-loop region of mitochondrial DNA is associated with renal cell carcinoma outcome

Accumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) has been described in various types of cancers and might be associated with cancer risk and disease outcome. We identified 14 SNPs with a frequency higher than 5% and 5 SNPs associated with the risk of renal cell carcinoma (RCC) in a case-control study previously. In the present study, we assessed the relationship of these SNPs and the outcome of RCC patients, a SNP of 262C/T was identified by the log-rank test for statistically significant prediction of RCC survival. In an overall multivariate analysis, allele 262 was identified as an independent predictor of RCC outcome. The length of survival of patients with 262T was significantly shorter than that of patients with allele 262C (relative risk, 2.136, 95%CI, 1.863-2.449; p = 0.000). The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify patients subgroup at high risk of a poor disease outcome.

Combined diffusion-weighted, blood oxygen level-dependent, and dynamic contrast-enhanced MRI for characterization and differentiation of renal cell carcinoma

PURPOSE

To investigate a multiparametric magnetic resonance imaging (MRI) approach comprising diffusion-weighted imaging (DWI), blood oxygen-dependent (BOLD), and dynamic contrast-enhanced (DCE) MRI for characterization and differentiation of primary renal cell carcinoma (RCC).

MATERIAL AND METHODS

Fourteen patients with clear-cell carcinoma and four patients with papillary RCC were examined with DWI, BOLD MRI, and DCE MRI at 1.5T. The apparent diffusion coefficient (ADC) was calculated with a monoexponential decay. The spin-dephasing rate R2* was derived from parametric R2* maps. DCE-MRI was analyzed using a two-compartment exchange model allowing separation of perfusion (plasma flow [FP] and plasma volume [VP]), permeability (permeability surface area product [PS]), and extravascular extracellular volume (VE). Statistical analysis was performed with Wilcoxon signed-rank test, Pearson's correlation coefficient, and receiver operating characteristic curve analysis.

RESULTS

Clear-cell RCC showed higher ADC and lower R2* compared to papillary subtypes, but differences were not significant. FP of clear-cell subtypes was significantly higher than in papillary RCC. Perfusion parameters showed moderate but significant inverse correlation with R2*. VE showed moderate inverse correlation with ADC. Fp and Vp showed best sensitivity for histological differentiation.

CONCLUSION

Multiparametric MRI comprising DWI, BOLD, and DCE MRI is feasible for assessment of primary RCC. BOLD moderately correlates to DCE MRI-derived perfusion. ADC shows moderate correlation to the extracellular volume, but does not correlate to tumor oxygenation or perfusion. In this preliminary study DCE-MRI appeared superior to BOLD and DWI for histological differentiation.

Bisebromoamide, an extract from Lyngbya species, induces apoptosis through ERK and mTOR inhibitions in renal cancer cells

Advanced renal cell carcinoma (RCC) remains an incurable disease, and newer anticancer drugs are needed. Bisebromoamide, a novel cytotoxic peptide, was isolated from the marine cyanobacterium Lyngbya species at our laboratory in 2009. This compound specifically inhibited the phosphorylation of ERK in platelet-derived growth factor-activated normal rat kidney cells. The aim of this study was to evaluate the effect and elucidate the potential mechanism of Bisebromoamide actions on human RCC cells. Two renal cancer cell lines, 769-P and 786-O, were used. The effects of Bisebromoamide were analyzed employing assays for water-soluble Tetrazolium-1 salts. Apoptosis was determined by flow cytometric TUNEL analysis. Cell-cycle distributions were analyzed by flow cytometry using BrdU/propidium iodide (PI) staining. Kinases of the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of Rapamycin (mTOR) pathway and Raf/MEK/ERK pathway were analyzed by Western blotting. After Bisebromoamide treatment for 48 and 72 h, cell viability was significantly decreased in both cell lines at 1 and 10 μmol/L. After treatment with 1 μmol/L Bisebromoamide for 72 h, apoptosis and the increased percentage of cells in the sub-G1 phase were observed in both cell lines. Bisebromoamide inhibited the phosphorylation of ERK and Akt in both cell lines tested. Similar effects were demonstrated for phosphorylation of mTOR and p70 S6. Bisebromoamide is a promising potential agent against RCC due to its ability to inhibit both the Raf/MEK/ERK and PI3K/Akt/mTOR pathways.

The role of pharmacogenomics in metastatic renal cell carcinoma

Pharmacogenomics is the study of how variation in the genetic background affects an individual's response to a specific drug and/or its metabolism. Using knowledge about the genes which produce the enzymes that metabolize a specific drug, a physician may decide to raise or lower the dose, or even change to a different drug. Targeted therapy with tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin (mTOR) inhibitors has led to a substantial improvement in the standard of care for patients with advanced or metastatic renal cell carcinoma (RCC). Although few studies have identified biomarkers that predict the response of targeted drugs in the treatment of metastatic RCC, some associations have been found. Several studies have identified genetic polymorphisms with implications in the pharmacokinetics and/or pharmacodynamics of TKIs and mTOR inhibitors and which are associated with a prolonged progression-free survival and/or overall survival in patients with metastatic RCC. Among the genes of interest, we should consider IL8, FGFR2, VEGFA, FLT4, and NR1I2. In this review, we discuss single nucleotide polymorphisms (SNPs) associated with outcome and toxicity following targeted therapies and provide recommendations for future trials to facilitate the use of SNPs in personalized therapy for this disease.

Evidence-Based Principles in Pathology: Existing Problem Areas and the Development of “Quality” Practice Patterns

Context.—Contrary to the intuitive impressions of many pathologists, several areas exist in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical “consumers” of laboratory services because of inadequate education, habit, or overreliance on empirical factors. Other faulty procedures are driven by pathologists themselves.

Objectives.—To consider (1) several selected problem areas representing non-EBM practices in laboratory medicine; such examples include ideas and techniques that concern metastatic malignancies, “targeted” oncologic therapy, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes; and (2) EBM principles as methods for remediation of deficiencies in hospital pathology, and implements for the construction of “quality” practices in our specialty.

Data Sources.—Current English literature relating to evidence-based principles in pathology and laboratory medicine, as well as the authors' experience.

Conclusions.—Evidence-based medicine holds the promise of optimizing laboratory services to produce “quality” practices in pathology. It will also be a key to restraining the overall cost of health care.

Gene expression profile of renal cell carcinoma clear cell type

PURPOSE

The determination of prognosis in patients with renal cell carcinoma (RCC) is based, classically, on stage and histopathological aspects. The metastatic disease develops in one third of patients after surgery, even in localized tumors. There are few options for treating those patients, and even the new target designed drugs have shown low rates of success in controlling disease progression. Few studies used high throughput genomic analysis in renal cell carcinoma for determination of prognosis. This study is focused on the identification of gene expression signatures in tissues of low-risk, high-risk and metastatic RCC clear cell type (RCC-CCT).

MATERIALS AND METHODS

We analyzed the expression of approximately 55,000 distinct transcripts using the Whole Genome microarray platform hybridized with RNA extracted from 19 patients submitted to surgery to treat RCC-CCT with different clinical outcomes. They were divided into three groups (1) low risk, characterized by pT1, Fuhrman grade 1 or 2, no microvascular invasion RCC; (2) high risk, pT2-3, Fuhrman grade 3 or 4 with, necrosis and microvascular invasion present and (3) metastatic RCC-CCT. Normal renal tissue was used as control.

RESULTS

After comparison of differentially expressed genes among low-risk, high-risk and metastatic groups, we identified a group of common genes characterizing metastatic disease. Among them Interleukin-8 and Heat shock protein 70 were over-expressed in metastasis and validated by real-time polymerase chain reaction.

CONCLUSION

These findings can be used as a starting point to generate molecular markers of RCC-CCT as well as a target for the development of innovative therapies.

Evaluation of response to multikinase inhibitor in metastatic renal cell carcinoma by FDG PET/contrast-enhanced CT

PURPOSE

Multikinase inhibitor (MKI) is a promising drug for treatment of metastatic renal cell carcinoma (mRCC). We explained the usefulness of [¹⁸F]-2-fluoro-2-deoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG PET/CECT) for mRCC in evaluating the early response to MKI and in predicting progression-free survival (PFS).

METHODS

Patients who planned MKI treatment for mRCC were included in this prospective study. FDG PET/CECT was performed before MKI treatment and after one cycle of MKI treatment. Evaluation of the response to MKI was assessed by PET according to the European Organization for Research and Treatment of Cancer, by CT according to the Response Evaluation Criteria in Solid Tumors and appearance of central hypoattenuation (CHA).

RESULTS

Twelve patients were enrolled in the study. Equality of response evaluation between PET and CT was in 8 patients (partial response [PR]: 1, stable disease [SD]: 6, progressive disease [PD]: 1). Among the other 4 patients, PET showed 2 patients with PR and 2 patients with PD, in contrast to the CT finding of SD in all 4 patients. PFS according to PET response showed a statistically significant difference between PR and SD (P < 0.05) and between PR and PD (P < 0.05), but not between PR and SD (P = 0.083). Positive CHA in metastatic lesions after MKI treatment was confirmed in 8 patients. PFS with positive CHA was 233.8 days, while that without CHA was 75.0 days (P < 0.05).

CONCLUSION

FDG PET/CECT shows potential for evaluating early treatment response to MKI in mRCC and for predicting PFS.

Combined positron emission tomography/computed tomography in sunitinib therapy assessment of patients with metastatic renal cell carcinoma

AIM

To assess the clinical benefit of combined functional imaging with [(18)F]2-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with metastatic renal cell carcinoma (mRCC) treated with the tyrosine kinase inhibitor sunitinib.

MATERIALS AND METHODS

Fourteen patients with mRCC were prospectively enrolled in this study. All patients underwent PET/CT before receiving at least two cycles of sunitinib treatment. Three months after the onset of sunitinib treatment, a second PET/CT was carried out. The metabolic response evaluated from the PET (standard uptake value; SUV) was compared with the CT component of the PET/CT. The Response Evaluation Criteria in Solid Tumours criteria were used to assess the CT response and modified European Organization for Research and Treatment of Cancer criteria were used to assess the PET response.

RESULTS

Three main results were obtained: (1) Patients with relatively low 18F-FDG uptake before treatment (SUV<5) had a longer progression-free survival than those with a relatively high 18F-FDG uptake (P=0.006). (2) Patients with a partial metabolic response or stable metabolic disease after two courses of sunitinib had improved prognosis as compared with those with progressive metabolic disease (P=0.031). (3) There was a clear discrepancy between PET and CT as a tool for the evaluation of treatment response after two courses of sunitinib. PET indicated progressive disease in three patients, a partial response in six patients and stable disease in four patients. In contrast, CT concluded with progression in only one patient and stable disease in all other patients.

CONCLUSION

In patients with mRCC, a high baseline 18F-FDG uptake indicates aggressive disease, and the degree of reduction in 18F-FDG uptake after sunitinib treatment adds valuable prognostic information. Hence, the inclusion of PET results seems to improve the clinical counselling of patients with mRCC. Larger studies are needed to confirm these findings.

Sirolimus plus sorafenib in treating HCC recurrence after liver transplantation: A case report

A case of hepatocellular carcinoma (HCC) with pulmonary recurrence after liver transplantation for HCC is presented in this report. The patient showed disease progression on sorafenib therapy demonstrated by computed tomography scans as well as serial serum α-fetoprotein (AFP) elevation. After his immunosuppression therapy was successfully transitioned to sirolimus and a continuation of sorafenib, he achieved partial remission based on RECIST criteria and normalization of AFP. Mammalian target of rapamycin inhibitors including sirolimus alone or in conjunction with sorafenib may be useful in the treatment of post transplant HCC.

Assessment of angiogenic factor, vascular endothelial growth factor, serum and urine level changes in superficial bladder tumor immunotherapy by intravesical Bacillus Calmette-Guerin

Background and Aim:

Bladder tumor is one of the most common genitourinary tumors. Management of non-muscle invasive (NMI) bladder tumors is primarily by transurethral resection (TURBT) followed by intravesical immunotherapy or chemotherapy. Bacillus Calmette-Guerin (BCG) is the most effective adjuvant therapy in NMI bladder tumor. Since angiogenesis is an essential factor in solid tumor progression and vascular endothelial growth factor (VEGF) is an important factor in angiogenesis, the aim of this study is the assessment of angiogenic factor, VEGF, serum and urine level changes in superficial bladder tumor immunotherapy by intravesical BCG.

Materials and Methods:

A total of 23 patients with bladder transitional cell carcinoma (TCC) in stage Ta/T1 or carcinoma insitu (CIS), low or high grade, which passed a 2-4 week period from TURBT participated in this study. Blood and urine samples were obtained at first and sixth sessions before instillation of BCG. Enzyme-linked immunosorbent assay (ELISA) method was used to obtain VEGF level in samples.

Results:

Urine and serum VEGF levels did not change significantly before and after BCG therapy. Changes in VEGF level were significantly different neither in low grade against high grade tumors nor in stage T1 against stage Ta tumors. A significant difference in VEGF level was seen between low grade and high grade tumors in serum after BCG therapy (P=0.007); but not in urine samples.

Conclusion:

Although intravesical BCG possesses anti-angiogenic activity, it seems that it exerts its effect through pathways other than VEGF, especially in low grade tumors.

Randomized phase II trial of first-line treatment with sorafenib versus interferon Alfa-2a in patients with metastatic renal cell carcinoma

PURPOSE

An open-label, phase II study to evaluate progression-free survival (PFS), overall best response, adverse events (AEs), and patient-reported outcomes with sorafenib versus interferon alfa-2a (IFN-alpha-2a) in patients with untreated, advanced renal cancer.

PATIENTS AND METHODS

A total of 189 patients were randomly assigned to oral sorafenib 400 mg twice daily or to subcutaneous IFN-alpha-2a 9 million U three times weekly (period 1). Sorafenib patients who progressed were dose-escalated to 600 mg twice daily; IFN-alpha-2a patients who progressed were switched to sorafenib 400 mg twice daily (period 2).

RESULTS

In period 1 PFS was similar for sorafenib-treated (n = 97; 5.7 months) and IFN-alpha-2a-treated patients (n = 92; 5.6 months); more sorafenib-treated patients had tumor shrinkage (68.2% v 39.0%). Common drug-related AEs (Grades > or = 3) for sorafenib were hand-foot skin reaction (11.3%), diarrhea (6.2%), and rash/desquamation (6.2%); for IFN-alpha-2a, these were fatigue (10.0%), nausea (3.3%), flu-like syndrome (2.2%), and anorexia (2.2%). Sorafenib-treated patients reported fewer symptoms, better quality of life (QOL), and greater treatment satisfaction. In period 2, 41.9% of patients who received sorafenib 600 mg twice daily (n = 43) experienced tumor reduction (median PFS, 3.6 months). After the switch to sorafenib 400 mg twice daily, tumors were reduced in 76.2% of 50 patients (median PFS, 5.3 months). AEs were mostly grade 1 to 2; no increase in AEs of grades > or = 3 occurred after sorafenib dose escalation.

CONCLUSION

In this study, sorafenib resulted in similar PFS as IFN-alpha-2a in patients with untreated RCC. However, sorafenib-treated patients experienced greater rates of tumor size reduction, better QOL, and improved tolerability. Both dose escalation of sorafenib after progression and a switch to sorafenib after progression on IFN-alpha-2a resulted in clinical benefit.

Reverse transcriptase inhibitors induce cell differentiation and enhance the immunogenic phenotype in human renal clear-cell carcinoma

Reverse transcriptase (RT) inhibitors are emerging as a novel class of anticancer differentiating agents, active in several human tumor cell models, such as melanoma and prostate, thyroid and colon carcinoma. Indeed, much evidence suggests that they may act by inhibiting endogenous RT, a gene highly expressed in undifferentiated and transformed cells. We therefore evaluated whether endogenous RT may represent a new molecular target in the treatment of human renal clear-cell carcinoma, a neoplasm with very low sensitivity to standard pharmacological therapies. Efavirenz and nevirapine, 2 non-nucleosidic RT inhibitors commonly used in HIV patients, either induced a reversible downregulation of cell proliferation or enhanced cell differentiation in primary cultures of human renal carcinoma cells characterized by high levels of endogenous RT activity. Both agents upregulated the expression of the vitamin D receptor and calbindin 28k genes, which are constitutively expressed in renal tubular cells, and induced vitamin D signaling by enhancing the ability of tumor cells to upregulate the vitamin D-dependent gene, CYP24. Furthermore, efavirenz- and nevirapine-differentiated tumor cells exhibited an immunogenic phenotype with an increased expression of HLA-I and CD40 antigens and an enhanced ability to elicit a specific T-cell response in mixed lymphocyte/tumor-cell cultures. Indeed, renal carcinoma cells exposed to efavirenz induced a CD8(+)CCR7-CD45RA(-) effector memory T-cell phenotype, whereas untreated RCC cells induced a CD8(+)CCR7(+)CD45RA(-) central memory T-cell phenotype. These data suggest that RT inhibitors may be a novel tool in the treatment of human renal clear-cell carcinoma, potentially able to enhance the immunogenic potential of tumor cell.

Hypoxia-inducible factor-2alpha regulates the expression of TRAIL receptor DR5 in renal cancer cells

To understand the role of hypoxia-inducible factor (HIF)-2alpha in regulating sensitivity of renal cancer cells to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-induced apoptosis, we transfected wild-type and mutant von Hippel Lindau (VHL) proteins into TRAIL-sensitive, VHL-negative A498 cells. We find that wild-type VHL, but not the VHL mutants S65W and C162F that do not degrade HIF proteins, cause TRAIL resistance. Knock down of the HIF-2alpha protein by RNA interference (short hairpin RNA) blocked TRAIL-induced apoptosis, decreased the level of TRAIL receptor (DR5) protein and inhibited the transcription of DR5 messenger RNA. By using luciferase constructs containing the upstream region of the DR5 promoter, we demonstrate that HIF-2alpha stimulates the transcription of the DR5 gene by activating the upstream region between -448 and -1188. Because HIF-2alpha is thought to exert its effect on gene transcription by interacting with the Max protein partner of Myc in the Myc/Max dimer, small interfering RNAs to Myc were used to lower the levels of this protein. In multiple renal cancer cell lines decreasing the levels of Myc blocked the ability of HIF-2alpha to stimulate DR5 transcription. PS-341 (VELCADE, bortezomib), a proteasome inhibitor used to treat human cancer, increases the levels of both HIF-2alpha and c-Myc and elevates the level of DR5 in renal cancer, sensitizing renal cancer cells to TRAIL therapy. Similarly, increasing HIF-2alpha in prostate and lung cancer cell lines increased the levels of DR5. Thus, in renal cancer cell lines expressing HIF-2alpha, this protein plays a role in regulating the levels of the TRAIL receptor DR5.

Sunitinib malate for the treatment of metastatic renal cell carcinoma and gastrointestinal stromal tumors

BACKGROUND

Sunitinib was approved by the US Food and Drug Administration (FDA) on January 26, 2006, for the treatment of metastatic renal cell carcinoma (mRCC) and gastrointestinal stromal tumor (GIST) in patients who have failed to respond to imatinib or were unable to tolerate it.

OBJECTIVE

This article reviews the pharmacology, pharmacokinetics, and pharmacodynamics of sunitinib; potential drug interactions; and the results of clinical trials evaluating its efficacy and tolerability.

METHODS

Pertinent literature was identified by searches of MEDLINE (1966-January 31, 2007), the American Society of Clinical Oncology abstracts database (2000-2007 annual meetings/symposia and previous meetings), and the FDA Web site (October 2006). Search terms included, but were not limited to, sunitinib, SUl1248, renal cell carcinoma, gastrointestinal stromal tumor, pharmacology, pharmacokinetic, adverse events, and clinical trial. Additional publications were found by scanning the reference lists of the identified articles.

RESULTS

Sunitinib is a potent inhibitor of multiple tyrosine kinase receptors. Its Tmax is reached within 6 to 12 hours, and food does not appear to affect its bioavailability. Sunitinib is metabolized by cytochrome P450 (CYP) 3A4 to an active metabolite, SU12662, which is further metabolized by CYP3A4 to an inactive moiety. The parent compound and active metabolite have similar biochemical activity and potency and reach similar plasma concentrations. Sunitinib and SU12662 have a tl/2 of 40 to 60 hours and 80 to 110 hours, respectively. Steady-state concentrations of both active entities are reached after 10 to 14 days of therapy. In a Phase III trial comparing sunitinib with interferon-alfa (IFN-00 as first-line therapy for mRCC, sunitinib was associated with a median progression-free survival of 11 months, compared with 5 months with IFN-cz (P < 0.001). A randomized, double-blind, placebo-controlled trial evaluating sunitinib as second-line therapy for GIST found a median time to progression of 28.9 weeks in the sunitinib arm, compared with 7 weeks in the placebo arm (hazard ratio = 0.28; P < 0.001). In Phase II trials, sunitinib also had anti-tumor activity in patients with breast cancer, neuroendocrine tumors, and non-small cell lung cancer. Further evaluation in these tumors, as well as in patients with acute myelogenous leukemia, may lead to expanded indications. The approved dose of sunitinib is 50 mg/d PO for 4 weeks, followed by a 2-week rest; this pattern is repeated until tumor progression or the occurrence of intolerable adverse effects. The most common clinical toxicities attributable to sunitinib include diarrhea, mucositis/stomatitis, hypertension, rash, skin discoloration, and altered taste, whereas commonly occurring laboratory abnormalities have been seen in association with gastrointestinal toxicity, renal toxicity, and hematologic toxicity. Of grade 3/4 toxicities occurring with sunitinib (which are relatively uncommon [<10%]), those that are clinically important include hypertension, diarrhea, fatigue, and hand-foot syndrome.

CONCLUSIONS

Sunitinib is a multiple tyrosine kinase receptor inhibitor approved for the treatment of mRCC and GIST. Evidence for long-term clinical benefit in renal cell cancer and other tumors awaits the results of ongoing trials.

Targeting MEK1/2 blocks osteoclast differentiation, function and cytokine secretion in multiple myeloma

Osteolytic bone disease in multiple myeloma (MM) is associated with upregulation of osteoclast (OCL) activity and constitutive inhibition of osteoblast function. The extracellular signal-regulated kinase 1/2 (ERK1/2) pathway mediates OCL differentiation and maturation. We hypothesized that inhibition of ERK1/2 could prevent OCL differentiation and downregulate OCL function. It was found that AZD6244, a mitogen-activated or extracellular signal-regulated protein kinase (MEK) inhibitor, blocked OCL differentiation and formation in a dose-dependent manner, evidenced by decreased alphaVbeta3-integrin expression and tartrate-resistant acid phosphatase positive (TRAP+) cells. Functional dentine disc cultures showed inhibition of OCL-induced bone resorption by AZD6244. Major MM growth and survival factors produced by OCLs including B-cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL), as well as macrophage inflammatory protein (MIP-1alpha), which mediates OCL differentiation and MM, were also significantly inhibited by AZD6244. In addition to ERK inhibition, NFATc1 (nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1) and c-fos were both downregulated, suggesting that AZD6244 targets a later stage of OCL differentiation. These results indicate that AZD6244 inhibits OCL differentiation, formation and bone resorption, thereby abrogating paracrine MM cell survival in the bone marrow microenvironment. The present study therefore provides a preclinical rationale for the evaluation of AZD6244 as a potential new therapy for patients with MM.

Targeting MEK induces myeloma-cell cytotoxicity and inhibits osteoclastogenesis

Activation of the extracellular signal-regulated kinase1/2 (ERK1/2) signaling cascade mediates human multiple myeloma (MM) growth and survival triggered by cytokines and adhesion to bone marrow stromal cells (BMSCs). Here, we examined the effect of AZD6244 (ARRY-142886), a novel and specific MEK1/2 inhibitor, on human MM cell growth in the bone marrow (BM) milieu. AZD6244 blocks constitutive and cytokine-stimulated ERK1/2 phosphorylation and inhibits proliferation and survival of human MM cell lines and patient MM cells, regardless of sensitivity to conventional chemotherapy. Importantly, AZD6244 (200 nM) induces apoptosis in patient MM cells, even in the presence of exogenous interleukin-6 or BMSCs associated with triggering of caspase 3 activity. AZD6244 sensitizes MM cells to both conventional (dexamethasone) and novel (perifosine, lenalidomide, and bortezomib) therapies. AZD6244 down-regulates the expression/secretion of osteoclast (OC)-activating factors from MM cells and inhibits in vitro differentiation of MM patient PBMCs to OCs induced by ligand for receptor activator of NF-kappaB (RANKL) and macrophage-colony stimulating factor (M-CSF). Finally, AZD6244 inhibits tumor growth and prolongs survival in vivo in a human plasmacytoma xenograft model. Taken together, these results show that AZD6244 targets both MM cells and OCs in the BM microenvironment, providing the preclinical framework for clinical trials to improve patient outcome in MM.

Newborn humans manifest autoantibodies to defined self molecules detected by antigen microarray informatics

Autoimmune diseases are often marked by autoantibodies binding to self antigens. However, many healthy persons also manifest autoantibodies that bind to self antigens, known as natural autoantibodies. In order to characterize natural autoantibodies present at birth, we used an antigen microarray (antigen chip) to analyze informatically (with clustering algorithms and correlation mapping) the natural IgM, IgA, and IgG autoantibody repertoires present in 10 pairs of sera from healthy mothers and the cords of their newborn babies. These autoantibodies were found to bind to 305 different, mostly self, molecules. We report that in utero, humans develop IgM and IgA autoantibodies to relatively uniform sets of self molecules. The global patterns of maternal IgM autoantibodies significantly diverged from those at birth, although certain reactivities remained common to both maternal and cord samples. Because maternal IgG antibodies (unlike IgM and IgA) cross the placenta, maternal and cord IgG autoantibodies showed essentially identical reactivities. We found that some self antigens that bind cord autoantibodies were among the target self antigens associated with autoimmune diseases later in life. Thus, the obviously benign autoimmunity prevalent at birth may provide the basis for the emergence of some autoimmune diseases relatively prevalent later in life.

Bee venom secretory phospholipase A2 and phosphatidylinositol-homologues cooperatively disrupt membrane integrity, abrogate signal transduction and inhibit proliferation of renal cancer cells

Bee venom secretory phospholipase A2 (bv-sPLA2) and phosphatidylinositol-(3,4)-bisphosphate (PtdIns(3,4)P2) act synergistically to induce cell death in tumour cells of various origins with concomitant stimulation of the immune system. Here, we investigated the mechanisms involved in such actions and examined structural requirements of PtdIns-homologues to inhibit tumour cells in combination with bv-sPLA2. Renal cancer cells were treated with bv-sPLA2 alone or in combination with PtdIns-homologues. Inhibitory effects on [(3)H] thymidine incorporation and intracellular signal transduction pathways were tested. Reaction products generated by bv-sPLA2 interaction with PtdIns(3,4)P2 were identified by mass spectrometry. Among the tested PtdIns-homologues those with a phosphate esterified to position 3 of the inositol head group, were most efficient in cooperating with bv-sPLA2 to block tumour cell proliferation. Growth inhibition induced by the combined action of bv-sPLA2 with either PtdIns(3,4)bisphosphate or PtdIns(3,4,5)trisphosphate were synergistic and accompanied by potent cell lysis. In contrast, PtdIns, which lacked the phosphate group at position 3, failed to promote synergistic growth inhibition. The combined administration of PtdIns(3,4)P2 and bv-sPLA2 abrogated signal transduction mediated by extracellular signal regulated kinase 1 and 2 and prevented transduction of survival signals mediated by protein kinase B. Surface expression of the epidermal growth factor (EGF)-receptor was reduced after PtdIns(3,4)P2-bv-sPLA2 administration and associated with a blockade of EGF-induced signalling. In addition, mass spectroscopy revealed that bv-sPLA2 cleaves PtdIns(3,4)P2 to generate lyso-PtdIns(3,4)P2. In conclusion, we suggest that the cytotoxic activity mediated by PtdIns(3,4)P2 and bv-sPLA2 is due to cell death that results from disruption of membrane integrity, abrogation of signal transduction and the generation of cytotoxic lyso-PtdIns(3,4)P2.

Loss of vascular endothelial growth factor expression reduces vascularization, but not growth, of tumors lacking the Von Hippel-Lindau tumor suppressor gene

Individuals bearing germ line mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene are predisposed to the development of highly angiogenic tumors. This is correlated with an increased expression of the angiogenic factor vascular endothelial growth factor (VEGF) in these tumors, which is in part caused by elevated expression of the HIF-1 hypoxia inducible transcription factors. We created malignant astrocytes with genetic deletions of the VHL gene and implanted them in subcutaneous and intracranial sites; these sites are respectively vessel poor and vessel-rich tissues. When grown in a vessel poor site, VEGF expression in VHL null cells was important for both vascularization and tumor growth. However, when the same cells are grown in the vessel-rich intracranial environment, loss of VEGF expression reduces vascularization, but does not affect tumor growth. This indicates that antiangiogenic therapies for tumors that express high levels of angiogenic factors such as VEGF may vary in their efficacy, with potentially lowered effectiveness in sites, such as the brain, that are inherently vessel rich.

Genomics of Renal Cell Cancer: The Biology Behind and the Therapy Ahead

Renal cell cancer (RCC) is the most lethal of the urological cancers and accounts for 3% of all adult malignancies. Despite numerous recent advances in diagnostic imaging, surgical therapy, and basic molecular understanding, many patients still experience metastatic disease. For metastatic disease patients, response rates to conventional therapies rarely exceed 15% to 25% and are associated with serious adverse effects. The recent development of novel targeted therapies based on the precise biological pathways deregulated in a particular patient has paved the way for individualized, targeted patient management. Nevertheless, to achieve this goal, it is important to delineate the molecular mechanisms underlying cancer development and progression. Genomic approaches have revolutionized the field of cancer research and have led to the rapid discovery of multiple, parallel disease hypotheses, which ultimately have to be validated in large cohorts of patients and in downstream biological experiments for translation into clinical applications. The variable course of RCC and, until recently, a paucity of therapeutic options in the event of metastasis have led to the search for diagnostic and prognostic markers. We and others have used transcriptional profiling to classify different subtypes of RCC and to identify subtype- and metastasis-specific gene signatures predictive for outcome. We discuss herein recent genomic approaches to RCC and the emerging biological pathways underlying RCC development and progression. We also speculate how genomics may affect drug development and the management of patients with RCC.

Tumor cell invasion of von Hippel Lindau renal cell carcinoma cells is mediated by membrane type-1 matrix metalloproteinase

Background

Metastatic renal cell carcinoma (RCC) remains the leading cause of mortality in patients with clear cell RCC arising from mutations in the von Hippel Lindau (VHL) tumor suppressor. Successful RCC tumor suppression by VHL requires the negative regulation of hypoxia inducible factor alpha (HIF alpha) protein and its downstream targets. Thus, identification of HIF target genes responsible for RCC tumor progression will aid in the development of therapies for this disease. We previously identified membrane type-1 matrix metalloproteinase (MT1-MMP) as a transcriptional target of HIF-2alpha in RCC cells null for VHL and showed that MT1-MMP is overexpressed in these cells. MT1-MMP is a key regulator of tumor progression through its functions as a matrix-degrading enzyme, as well as its ability to cleave factors, such as adhesion molecules and other MMPs. The aim of this study was to investigate the contribution of MT1-MMP to the invasive potential of RCC cells using in vitro type I collagen degradation and invasion assays.

Results

We evaluated RCC cells wild-type (WT8) and null (pRc-9) for VHL for invasive characteristics and showed that the pRc-9 cells demonstrated a greater propensity for both invasion and degradation of a type I collagen matrix. Furthermore, overexpression of either HIF-2alpha or MT1-MMP in the poorly invasive cell line, WT8, promoted collagen degradation and invasion of these cells. Finally, using RNAi, we show that inhibition of MT1-MMP suppresses tumor cell invasion of RCC cells.

Conclusion

Our results suggest that MT1-MMP is a major mediator of tumor cell invasiveness and type I collagen degradation by VHL RCC cells that express either MT1-MMP or HIF-2alpha. As such, MT1-MMP may represent a novel target for anti-invasion therapy for this disease.