Emerging evidence for CHFR as a cancer biomarker: from tumor biology to precision medicine.

Novel insights in the biology of cancer have switched the paradigm of a "one-size-fits-all" cancer treatment to an individualized biology-driven treatment approach. In recent years, a diversity of biomarkers and targeted therapies has been discovered. Although these examples accentuate the promise of personalized cancer treatment, for most cancers and cancer subgroups no biomarkers and effective targeted therapy are available. The great majority of patients still receive unselected standard therapies with no use of their individual molecular characteristics. Better knowledge about the underlying tumor biology will lead the way toward personalized cancer treatment. In this review, we summarize the evidence for a promising cancer biomarker: checkpoint with forkhead and ring finger domains (CHFR). CHFR is a mitotic checkpoint and tumor suppressor gene, which is inactivated in a diverse group of solid malignancies, mostly by promoter CpG island methylation. CHFR inactivation has shown to be an indicator of poor prognosis and sensitivity to taxane-based chemotherapy. Here we summarize the current knowledge of altered CHFR expression in cancer, the impact on tumor biology and implications for personalized cancer treatment.

Real-world effectiveness of systemic agents approved for advanced non-small cell lung cancer: a SEER-Medicare analysis.

OBJECTIVES: Disparity exists between patients with lung cancer enrolled in clinical trials and patients treated in the community setting. This study assessed the real-world effectiveness of cytotoxic agents that became available for the treatment of non-small cell lung cancer (NSCLC) in the last 2 decades. METHODS: We employed the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database for patients diagnosed with stage IIIB/IV NSCLC between 1988 and 2005 to assess the effectiveness of newly approved agents. Effectiveness of specific agents was assessed at time periods immediately following the approval of the agent for NSCLC: baseline, 1988-1994; platinum, 1995-1999; docetaxel, 1999-2003; pemetrexed and bevacizumab, 2004-2005. Significant associations between specific drug treatment and survival improvement were determined using the Kaplan-Meier method, Cox proportional hazard model, and propensity score analyses. Significant differences were established by log-rank test. RESULTS: This analysis employed data from 143,548 patients by sex (58% male, 42% female), cancer stage (35% stage IIIB, 65% stage IV), and age (12% 20-64 years, 22% 65-69 years, 45% 70-79 years, 22% 80 years and older). There was temporal improvement in survival for patients treated with newly approved chemotherapy (1-year survival rates: 32.41% in 1988-1994, 32.95% in 1995-1998, 37.40% in 1999-2003, and 39.55% in 2004-2005). Patients treated with a newly approved drug during the relevant treatment era had a significant reduction in the risk of death when compared with patients treated with chemotherapy other than the newly approved agent (hazard ratios [95% confidence interval] were 0.76 [0.71-0.81] for platinum, 0.73 [0.70-0.75] for docetaxel, 0.40 [0.37-0.44] for pemetrexed, and 0.33 [0.27-0.40] for bevacizumab; p < .001). Propensity score adjustment did not significantly alter these results. CONCLUSIONS: Currently approved drugs for the treatment of advanced NSCLC are associated with improved survival in the U.S. Medicare patient population. Our findings support the effectiveness of these agents in the real-world oncology practice.

Enhanced anti-tumor activity by the combination of the natural compounds (-)-epigallocatechin-3-gallate and luteolin: potential role of p53.

Natural dietary agents have drawn a great deal of attention toward cancer prevention because of their wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasingly popularity. In the present study, we investigated a combinatorial approach using two natural dietary polyphenols, luteolin and EGCG, and found that their combination at low doses (at which single agents induce minimal apoptosis) synergistically increased apoptosis (3-5-fold more than the additive level of apoptosis) in both head and neck and lung cancer cell lines. This combination also significantly inhibited growth of xenografted tumors in nude mice. The in vivo findings also were supported by significant inhibition of Ki-67 expression and increase in TUNEL-positive cells in xenografted tissues. Mechanistic studies revealed that the combination induced mitochondria-dependent apoptosis in some cell lines and mitochondria-independent apoptosis in others. Moreover, we found more efficient stabilization and ATM-dependent Ser(15) phosphorylation of p53 due to DNA damage by the combination, and ablation of p53 using shRNA strongly inhibited apoptosis as evidenced by decreased poly(ADP-ribose) polymerase and caspase-3 cleavage. In addition, we observed mitochondrial translocation of p53 after treatment with luteolin or the combination of EGCG and luteolin. Taken together, our results for the first time suggest that the combination of luteolin and EGCG has synergistic/additive growth inhibitory effects and provides an important rationale for future chemoprevention trials of head and neck and lung cancers.

Molecular characteristics of non-small cell lung cancer with reduced CHFR expression in The Cancer Genome Atlas (TCGA) project.

BACKGROUND: CHFR expression has previously been established as a powerful predictor for response to taxane based first-line chemotherapy in non-small cell lung cancer. It is currently unknown however, if reduced CHFR expression correlates with certain molecular subtypes of lung cancer. PURPOSE: In order to determine which patients may benefit from CHFR biomarker testing we conducted the present study to characterize clinical and molecular characteristics of patients with reduced vs. high CHFR expression. APPROACH: We utilized the extensive molecular and clinical data of the most recent adeno- and squamous cell carcinoma datasets from The Cancer Genome Atlas (TCGA) project. CHFR expression, analyzed by RNA-seq, was classified as high vs. low based on the median CHFR expression level and correlated with the presence or absence of lung cancer specific mutations (EGFR, KRAS, ALK, MET, ERBB2, TP53, STK11, ROS1, RET, NF1, Pik3CA for adenocarcinomas and FGFR1, FGFR2, FGFR3, TP53, STK11, EGFR for squamous cell carcinomas). RESULTS: Reduced CHFR expression was associated with EGFR exon19/21 mutations in adenocarcinoma OR 0.23 (95%CI: 0.06-0.88) and male gender in squamous cell carcinoma (OR 0.46 (95%CI 0.23-0.92), p = 0.02).

Small molecule inhibition of the CHFR-PARP1 interaction as novel approach to overcome intrinsic taxane resistance in cancer.

The mitotic checkpoint protein CHFR has emerged as a major mediator of taxane resistance in cancer. Here we show that CHFR's PAR-binding zinc finger domain (PBZ) mediates a protein interaction with poly-ADP ribosylated PARP1 leading to stabilization of CHFR. Disruption of the CHFR-PARP1 interaction through either PARP1 shRNA-mediated knockdown or overexpression of a PBZ domain peptide induces loss of CHFR protein expression. In an attempt to exploit this observation therapeutically, and to develop compounds with synthetic lethality in combination with taxanes, we performed a high-throughput computational screen of 5,256,508 chemical structures against the published crystal structure of the CHFR PBZ domain to identify candidate small molecule CHFR protein-protein interaction inhibitors. The 10 compounds with the best docking scores (< -9.7) were used for further in vitro testing. One lead compound in particular, termed 'A3', completely disrupted the protein-protein interaction between CHFR and PARP1, resulting in the inhibition of mitotic checkpoint function, and led to therapeutic synergy with docetaxel in cell viability and colony formation assays. In mouse xenografts, i.p. administration of 'A3' led to a significant reduction in nuclear CHFR protein expression with a maximal effect 4 hours after administration, confirming relevant pharmacodynamics following the peak of 'A3' plasma concentration in vivo. Furthermore, combination of A3 and taxane led to significant reduction of implanted tumor size without increase in hematological, hepatic or renal toxicity. These findings provide a proof-of-principle that small molecule inhibition of CHFR PBZ domain interaction is a novel potential therapeutic approach to increase the efficacy of taxane-based chemotherapy in cancer.

Could valproic acid be an effective anticancer agent? The evidence so far.

Valproic acid is an inhibitor of class I histone deacetylases. Epigenetic therapies in cancer have been focus of a keen interest and histone deacetylase inhibitors, in particular, have been approved for certain types of hematologic malignancies. Valproic acid is an attractive candidate for cancer therapy due to its mechanism of action, its low cost and generally good clinical tolerability. In the following editorial, we will review its role as monotherapy for cancer, its place in combination epigenetic therapy, and its role as chemosensitizer, and cancer preventative agent.

Aberrant promoter methylation of caveolin-1 is associated with favorable response to taxane-platinum combination chemotherapy in advanced NSCLC.

PURPOSE: Aberrant promoter DNA methylation can serve as a predictive biomarker for improved clinical responses to certain chemotherapeutics. One of the major advantages of methylation biomarkers is the ease of detection and clinical application. In order to identify methylation biomarkers predictive of a response to a taxane-platinum based chemotherapy regimen in advanced NSCLC we performed an unbiased methylation analysis of 1,536 CpG dinucleotides in cancer-associated gene loci and correlated results with clinical outcomes. METHODS: We studied a cohort of 49 patients (median age 62 years) with advanced NSCLC treated at the Atlanta VAMC between 1999 and 2010. Methylation analysis was done on the Illumina GoldenGate Cancer panel 1 methylation microarray platform. Methylation data were correlated with clinical response and adjusted for false discovery rates. RESULTS: Cav1 methylation emerged as a powerful predictor for achieving disease stabilization following platinum taxane based chemotherapy (p = 1.21E-05, FDR significance  = 0.018176). In Cox regression analysis after multivariate adjustment for age, performance status, gender, histology and the use of bevacizumab, CAV1 methylation was significantly associated with improved overall survival (HR 0.18 (95%CI: 0.03-0.94)). Silencing of CAV1 expression in lung cancer cell lines(A549, EKVX)by shRNA led to alterations in taxane retention. CONCLUSIONS: CAV1 methylation is a predictor of disease stabilization and improved overall survival following chemotherapy with a taxane-platinum combination regimen in advanced NSCLC. CAV1 methylation may predict improved outcomes for other chemotherapeutic agents which are subject to cellular clearance mediated by caveolae.

Class I HDACs are mediators of smoke carcinogen-induced stabilization of DNMT1 and serve as promising targets for chemoprevention of lung cancer.

DNA methylation is an early event in bronchial carcinogenesis and increased DNA methyltransferase (DNMT)1 protein expression is a crucial step in the oncogenic transformation of epithelia. Here, we investigate the role of class I histone deacetylases (HDAC) 1 to 3 in the stabilization of DNMT1 protein and as a potential therapeutic target for lung cancer chemoprevention. Long-term exposure of immortalized bronchial epithelial cells (HBEC-3KT) to low doses of tobacco-related carcinogens led to oncogenic transformation, increased HDAC expression, cell-cycle independent increased DNMT1 stability, and DNA hypermethylation. Overexpression of HDACs was associated with increased DNMT1 stability and knockdown of HDACs reduced DNMT1 protein levels and induced DNMT1 acetylation. This suggests a causal relationship among increased class I HDACs levels, upregulation of DNMT1 protein, and subsequent promoter hypermethylation. Targeting of class I HDACs with valproic acid (VPA) was associated with reduced HDAC expression and a profound reduction of DNMT1 protein level. Treatment of transformed bronchial epithelial cells with VPA resulted in reduced colony formation, demethylation of the aberrantly methylated SFRP2 promoter, and derepression of SFRP2 transcription. These data suggest that inhibition of HDAC activity may reverse or prevent carcinogen-induced transformation. Finally, immunohistochemistry on human lung cancer specimens revealed a significant increase in DNMT1, HDAC1, HDAC2, and HDAC3 expression, supporting our hypotheses that class I HDACs are mediators of DNMT1 stability. In summary, our study provides evidence for an important role of class I HDACs in controlling the stability of DNMT1 and suggests that HDAC inhibition could be an attractive approach for lung cancer chemoprevention.

Chemoprevention of head and neck cancer by simultaneous blocking of epidermal growth factor receptor and cyclooxygenase-2 signaling pathways: preclinical and clinical studies.

PURPOSE: We investigated the efficacy and underlying molecular mechanism of a novel chemopreventive strategy combining EGF receptor (EGFR) tyrosine kinase inhibitor (TKI) with cyclooxygenase-2 inhibitor (COX-2I). EXPERIMENTAL DESIGN: We examined the inhibition of tumor cell growth by combined EGFR-TKI (erlotinib) and COX-2I (celecoxib) treatment using head and neck cancer cell lines and a preventive xenograft model. We studied the antiangiogenic activity of these agents and examined the affected signaling pathways by immunoblotting analysis in tumor cell lysates and immunohistochemistry (IHC) and enzyme immunoassay (EIA) analyses on the mouse xenograft tissues and blood, respectively. Biomarkers in these signaling pathways were studied by IHC, EIA, and an antibody array analysis in samples collected from participants in a phase I chemoprevention trial of erlotinib and celecoxib. RESULTS: The combined treatment inhibited head and neck cancer cell growth significantly more potently than either single agent alone in cell line and xenograft models, and resulted in greater inhibition of cell-cycle progression at G1 phase than either single drug. The combined treatment modulated the EGFR and mTOR signaling pathways. A phase I chemoprevention trial of combined erlotinib and celecoxib revealed an overall pathologic response rate of 71% at time of data analysis. Analysis of tissue samples from participants consistently showed downregulation of EGFR, pERK, and pS6 levels after treatment, which correlated with clinical response. CONCLUSION: Treatment with erlotinib combined with celecoxib offers an effective chemopreventive approach through inhibition of EGFR and mTOR pathways, which may serve as potential biomarkers to monitor the intervention of this combination in the clinic. Clin Cancer Res; 19(5); 1244-56. ©2013 AACR.

CHFR protein expression predicts outcomes to taxane-based first line therapy in metastatic NSCLC.

PURPOSE: Currently, there is no clinically validated test for the prediction of response to tubulin-targeting agents in non-small cell lung cancer (NSCLC). Here, we investigated the significance of nuclear expression of the mitotic checkpoint gene checkpoint with forkhead and ringfinger domains (CHFR) as predictor of response and overall survival with taxane-based first-line chemotherapy in advanced stage NSCLC. METHODS: We studied a cohort of 41 patients (median age 63 years) with advanced NSCLC treated at the Atlanta VAMC between 1999 and 2010. CHFR expression by immunohistochemistry (score 0-4) was correlated with clinical outcome using chi-square test and Cox proportional models. A cutoff score of "3" was determined by receiver operator characteristics analysis for "low" CHFR expression. Results were validated in an additional 20 patients who received taxane-based chemotherapy at Emory University Hospital and the Atlanta VAMC. RESULTS: High expression (score = 4) of CHFR is strongly associated with adverse outcomes: the risk for progressive disease after first-line chemotherapy with carboplatin-paclitaxel was 52% in patients with CHFR-high versus only 19% in those with CHFR-low tumors (P = 0.033). Median overall survival was strongly correlated with CHFR expression status (CHFR low: 9.9 months; CHFR high: 6.2 months; P = 0.002). After multivariate adjustment, reduced CHFR expression remained a powerful predictor of improved overall survival (HR = 0.24; 95% CI, 0.1-0.58%; P = 0.002). In the validation set, low CHFR expression was associated with higher likelihood of clinical benefit (P = 0.03) and improved overall survival (P = 0.038). CONCLUSIONS: CHFR expression is a novel predictive marker of response and overall survival in NSCLC patients treated with taxane-containing chemotherapy.

Targeted therapy of non-small-cell lung carcinoma.

The rapid expansion of novel technologies in cancer research over the past several years has led to a dramatically improved understanding of the molecular biology of lung cancer. As a consequence, novel targeted therapies are rapidly being developed. In this review, we summarize the most important molecular pathways in lung cancer and describe the clinical evidence for the development of therapies against these targets.

Cancer DNA methylation: molecular mechanisms and clinical implications.

DNA methylation plays a crucial role in the regulation of gene expression and chromatin organization within normal eukaryotic cells. In cancer, however, global patterns of DNA methylation are altered with global hypomethylation of repeat-rich intergenic regions and hypermethylation of a subset of CpG-dense gene-associated regions (CpG islands). Extensive research has revealed the cellular machinery that catalyzes DNA methylation, as well as several large protein complexes that mediate the transcriptional repression of hypermethylated genes. However, research is only just beginning to uncover the molecular mechanisms underlying the origins of cancer-specific DNA methylation. Herein, we present several recent advances regarding these mechanisms and discuss the relationship between histone modifications (i.e., H3K4me2/3, H4K16Ac, H3K9me2/3, H3K27me3, H4K20me3), chromatin-modifying enzymes (G9a, EZH2, hMOF, SUV4-20H), and aberrant DNA methylation. Additionally, the role played by inflammation, DNA damage, and miRNAs in the etiology of aberrant DNA methylation is considered. Finally, we discuss the clinical implications of aberrant DNA methylation and the utility of methylated biomarkers in cancer diagnosis and management.

Occlusive endobronchial stent placement as a novel management approach to massive hemoptysis from lung cancer.

Massive hemoptysis in patients with advanced thoracic malignancies can be difficult to manage. Frequently, the bleeding source is not amenable to either bronchial artery embolization or surgical resection. Isolation of the bleeding source by endobronchial tamponade is an alternative management option. This is commonly achieved by the use of double-lumen endotracheal tubes or the placement of endobronchial balloons. Although effective, these approaches are not permanent solutions and may require prolonged intubation. We describe here an alternative, novel approach to endobronchial tamponade that does not require prolonged mechanical ventilation. We present a case in which massive hemoptysis from a left lower lobe cavitary lung cancer was successfully tamponaded and ultimately stopped by the placement of 2 covered self-expanding bronchial stents, allowing the patient to be extubated and to undergo further palliative therapy. No recurrent episodes of hemoptysis occurred throughout the patient's lifetime.

Alteration of pemetrexed excretion in the presence of acute renal failure and effusions: presentation of a case and review of the literature.

Pemetrexed is a multitargeted antifolate approved by the Food and Drug Administration for patients with mesothelioma and non small cell lung cancer. As this agent is almost exclusively cleared by renal excretion, trials leading to its approval were conducted in patients with normal renal function. However, this cycle active agent often is administered with cisplatin to patients who may have pleural effusions and ascites. As a result, the potential for drug accumulation in effusions and for accompanying renal insufficiency is real. Recommendations for the management of pemetrexed toxicity in the presence of renal failure have not been established. A case of treatment-related acute renal failure following chemotherapy with cisplatin and pemetrexed in a patient with advanced mesothelioma and ascites is presented. Pharmacologic studies in this patient revealed persistent pemetrexed levels in ascites and plasma. This is the first time that significant accumulation of pemetrexed in ascetic fluid has been reported in the literature. Treatment with leucovorin, folate, and continuous veno-venous hemodialysis was initiated. Thymidine and carboxypeptidase were not available. Dialysis was unsuccessful in removing pemetrexed. Theoretical and practical approaches to management of similar cases are presented.

CHFR promoter hypermethylation in colon cancer correlates with the microsatellite instability phenotype.

A subset of sporadic colon cancers has been shown to have microsatellite instability caused by an epigenetic inactivation of the MLH1 gene by hypermethylation of the the CpG island in its promoter region. We report here that in colorectal cancer, inactivation of the MLH1 gene is frequently accompanied by hypermethylation of the CpG island in the promoter of the mitotic gene checkpoint with forkhead and ring finger domains (CHFR). This was first observed in the colon cancer cell lines HCT-116, DLD-1, RKO and HT29. Among the 61 primary colon cancer samples studied, hypermethylation of the MLH1 and the CHFR promoter was found in 31% of the tumors. In 68% of all primary cancers (13/19) with MLH1 promoter hypermethylation, hypermethylation of the CHFR promoter was observed as well (P-value < 0.0001, Fisher's two-sided exact). Hypermethylation of the HLTF, MGMT, RASSF1, APC, p14 and p16 promoter regions were also frequent events, being observed in 48% (28/58), 40% (26/64), 21% (14/64), 50% (31/62), 43% (26/60) and 56% (35/63), respectively. However, methylation of these genes was not associated with methylation of either MLH1 or CHFR. The observed methylation profile was unrelated to Duke's stage. The coordinated loss of both mismatch repair caused by methylation of MLH1 and loss of checkpoint control associated with methylation of CHFR suggests the potential to overcome cell cycle checkpoints, which may lead to an accumulation of mutations.