Fusaric acid: A novel agent and mechanism to treat HNSCC

Autophagy modulation changes mechano-chemical sensitivity of T24 bladder cancer cells

Bladder cancer cells possess unique adaptive capabilities: shaped by their environment, cells face a complex chemical mixture of metabolites and xenobiotics accompanied by physiological mechanical cues. These responses might translate into resistance to chemotherapeutical regimens and can largely rely on autophagy. Considering molecules capable of rewiring tumor plasticity, compounds of natural origin promise to offer valuable options. Fungal derived metabolites, such as bafilomycin and wortmannin are widely acknowledged as autophagy inhibitors. Here, their potential to tune bladder cancer cells´ adaptability to chemical and physical stimuli was assessed. Additionally, dietary occurring mycotoxins were also investigated, namely deoxynivalenol (DON, 0.1-10 µM) and fusaric acid (FA, 0.1-1 mM). Endowing a Janus' face behavior, DON and FA are on the one side described as toxins with detrimental health effects. Concomitantly, they are also explored experimentally for selective pharmacological applications including anticancer activities. In non-cytotoxic concentrations, bafilomycin (BAFI, 1-10 nM) and wortmannin (WORT, 1 µM) modified cell morphology and reduced cancer cell migration. Application of shear stress and inhibition of mechano-gated PIEZO channels reduced cellular sensitivity to BAFI treatment (1 nM). Similarly, for FA (0.5 mM) PIEZO1 expression and inhibition largely aligned with the modulatory potential on cancer cells motility. Additionally, this study highlighted that the activity profile of compounds with similar cytotoxic potential (e.g. co-incubation DON with BAFI or FA with WORT) can diverge substantially in the regulation of cell mechanotransduction. Considering the interdependence between tumor progression and response to mechanical cues, these data promise to provide a novel viewpoint for the study of chemoresistance and associated pathways.

Fusaric acid inhibits proliferation and induces apoptosis through triggering endoplasmic reticulum stress in MCF-7 human breast cancer cells

Breast cancer has replaced lung cancer to be the leading cancer in the world. Currently, chemotherapy is still the major method for breast cancer therapy, but its overall effect remains unsatisfactory. Fusaric acid (FSA), a mycotoxin derived from fusarium species, has shown potency against the proliferation of several types of cancer cells, but its effect on breast cancer cells has not been examined. Therefore, we explored the possible effect of FSA on the proliferation of MCF-7 human breast cancer cells and uncovered the underlying mechanism in the present study. Our results showed that FSA has a strong anti-proliferative effect on MCF-7 cells through inducing ROS production, apoptosis and arresting cell cycle at G2/M transition phase. Additionally, FSA triggers endoplasmic reticulum (ER) stress in the cells. Notably, the cell cycle arrest and apoptosis inducing effect of FSA can be attenuated by ER stress inhibitor, tauroursodeoxycholic acid. Our study provide evidence that FSA is a potent proliferation inhibition and apoptosis inducing agent against human breast cancer cells, and the possible mechanism involves the activation of ER stress signaling pathways. Our study may highlight that FSA is promising for the future in vivo study and development of potential agent for breast cancer therapy.

Establishing a novel colorectal cancer predictive model based on unique gut microbial single nucleotide variant markers

Current metagenomic species-based colorectal cancer (CRC) microbial biomarkers may confuse diagnosis because the genetic content of different microbial strains, even those belonging to the same species, may differ from 5% to 30%. Here, a total of 7549 non-redundant single nucleotide variants (SNVs) were annotated in 25 species from 3 CRC cohorts (n = 249). Then, 22 microbial SNV markers that contributed to distinguishing subjects with CRC from healthy subjects were identified by the random forest algorithm to construct a novel CRC predictive model. Excitingly, the predictive model showed high accuracy both in the training (AUC = 75.35%) and validation cohorts (AUC = 73.08%-88.02%). We further explored the specificity of these SNV markers in a broader background by performing a meta-analysis across 4 metabolic disease cohorts. Among these SNV markers, 3 SNVs that were enriched in CRC patients and located in the genomes of Eubacterium rectale and Faecalibacterium prausnitzii were CRC specific (AUC = 72.51%-94.07%).

Fusaric acid-induced epigenetic modulation of hepatic H3K9me3 triggers apoptosis in vitro and in vivo

Aim: To determine the effect of the food-borne mycotoxin, fusaric acid (FA) on miR-200a, SUV39H1-mediated H3K9me3, genome integrity and apoptosis in human liver (HepG2) cells and C57BL/6 mice livers. Materials & methods: MiR-200a, Sirt1, SUV39H1-mediated H3K9me3, genome integrity and apoptosis was measured in HepG2 cells and C57BL/6 mice livers using qPCR, western blot, DNA electrophoresis and luminometry. Results: FA: upregulated miR-200a and decreased Sirt1 expression in HepG2 cells and mice livers; decreased expression of SUV39H1 and KDM4B, thus decreasing H3K9me3 and increasing H3K9me1; increased cell mortality via apoptosis. Conclusion: FA induced apoptosis by upregulating miR-200a and decreasing SUV39H1-mediated H3K9me3 in HepG2 cells and mice livers.

Fusaric acid-induced promoter methylation of DNA methyltransferases triggers DNA hypomethylation in human hepatocellular carcinoma (HepG2) cells

Fusaric acid (FA), a mycotoxin contaminant of maize, displays toxicity in plants and animals; however, its epigenetic mechanism is unknown. DNA methylation, an epigenetic modification that regulates gene expression, is mediated by DNA methyltransferases (DNMTs; DNMT1, DNMT3A, and DNMT3B) and demethylases (MBD2). The expression of DNMTs and demethylases are regulated by promoter methylation, microRNAs (miR-29b) and post-translational modifications (ubiquitination). Alterations in these DNA methylation modifying enzymes affect DNA methylation patterns and offer novel mechanisms of FA toxicity. We determined the effect of FA on global DNA methylation as well as a mechanism of FA-induced changes in DNA methylation by transcriptional (promoter methylation), post-transcriptional (miR-29b) and post-translational (ubiquitination) regulation of DNMTs and MBD2 in the human hepatocellular carcinoma (HepG2) cell line. FA induced global DNA hypomethylation (p < 0.0001) in HepG2 cells. FA decreased the mRNA and protein expression of DNMT1 (p < 0.0001), DNMT3A (p < 0.0001), and DNMT3B (p < 0.0001) by upregulating miR-29b (p < 0.0001) and inducing promoter hypermethylation of DNMT1 (p < 0.0001) and DNMT3B (p < 0.0001). FA decreased the ubiquitination of DNMT1 (p = 0.0753), DNMT3A (p = 0.0008), and DNMT3B (p < 0.0001) by decreasing UHRF1 (p < 0.0001) and USP7 (p < 0.0001). FA also induced MBD2 promoter hypomethylation (p < 0.0001) and increased MBD2 expression (p < 0.0001). Together these results indicate that FA induces global DNA hypomethylation by altering DNMT promoter methylation, upregulating miR-29b, and increasing MBD2 in HepG2 cells.

Fusaric Acid immunotoxicity and MAPK activation in normal peripheral blood mononuclear cells and Thp-1 cells

Fusaric acid (FA), a food-borne mycotoxin, is a potent divalent metal chelator. The human immune system is complex and susceptible to environmental insult however, the immunotoxity of FA remains unknown. We investigated the immunotoxicity of FA on human peripheral blood mononuclear cells (PBMCs) and Thp-1 cells. FA was cytotoxic to PBMCs (IC₅₀-240.8 μg/ml) and Thp-1 (IC₅₀-107.7 μg/ml) cells at 24 h. FA induced early apoptosis but significantly decreased caspase activity in PBMCs, a characteristic of paraptosis. In Thp-1 cells, FA induced apoptosis and increased caspase -9 and -3/7 activities. In PBMCs, FA maintained mitochondrial membrane potential and decreased protein expression of Bax whilst increasing expression of p-Bcl-2; FA induced oxidative stress and depleted ATP levels in both cell types. In Thp-1 cells, FA increased mitochondrial membrane depolarization and decreased p-Bcl-2 expression. In PBMCs, FA significantly up-regulated the MAPK protein expression of p-ERK and p-JNK but down-regulated p-p38 expression. In Thp-1 cells, FA up-regulated MAPK protein expression of p-ERK whilst p-JNK and p-p38 expression were down-regulated. In conclusion FA induced programmed cell death and altered MAPK signaling in healthy PBMCs and Thp-1 cells strongly suggesting a possible mechanism of FA induced immunotoxicity in vitro.

Fusaric Acid Induces DNA Damage and Post-Translational Modifications of p53 in Human Hepatocellular Carcinoma (HepG2 ) Cells

Fusaric acid (FA), a common fungal contaminant of maize, is known to mediate toxicity in plants and animals; however, its mechanism of action is unclear. p53 is a tumor suppressor protein that is activated in response to cellular stress. The function of p53 is regulated by post-translational modifications-ubiquitination, phosphorylation, and acetylation. This study investigated a possible mechanism of FA induced toxicity in the human hepatocellular carcinoma (HepG₂ ) cell line. The effect of FA on DNA integrity and post-translational modifications of p53 were investigated. Methods included: (a) culture and treatment of HepG₂ cells with FA (IC₅₀ : 580.32 μM, 24 h); (b) comet assay (DNA damage); (c) Western blots (protein expression of p53, MDM2, p-Ser-15-p53, a-K382-p53, a-CBP (K1535)/p300 (K1499), HDAC1 and p-Ser-47-Sirt1); and (d) Hoechst 33342 assay (apoptosis analysis). FA caused DNA damage in HepG₂ cells relative to the control (P < 0.0001). FA decreased the protein expression of p53 (0.24-fold, P = 0.0004) and increased the expression of p-Ser-15-p53 (12.74-fold, P = 0.0126) and a-K382-p53 (2.24-fold, P = 0.0096). This occurred despite the significant decrease in the histone acetyltransferase, a-CBP (K1535)/p300 (K1499) (0.42-fold, P = 0.0023) and increase in the histone deacetylase, p-Ser-47-Sirt1 (1.22-fold, P = 0.0020). The expression of MDM2, a negative regulator of p53, was elevated in the FA treatment compared to the control (1.83-fold, P < 0.0001). FA also inhibited cell proliferation and induced apoptosis in HepG₂ cells as evidenced by the Hoechst assay. Together, these results indicate that FA is genotoxic and post-translationally modified p53 leading to HepG₂ cell death. J. Cell. Biochem. 118: 3866-3874, 2017. © 2017 Wiley Periodicals, Inc.

Fusaric acid induces oxidative stress and apoptosis in human cancerous oesophageal SNO cells

Oesophageal cancer (OC) is a global problem incrementally incident among black South African males. The high incidence of OC may be due to the consumption of corn as a staple, often contaminated with mycotoxins. Fusaric acid (FA), a neglected mycotoxin, is known to disrupt mitochondrial energy metabolism, chelates divalent metal cations and induces cell death in plants. This study investigated FA-induced cytotoxicity and apoptotic induction in the SNO OC cell line. Cells were treated with FA (IC₅₀ = 78.81 μg/mL; 24 h; MTT assay) and assayed for oxidative stress and membrane damage (TBARS, LDH cytotoxicity and glutathione), apoptotic induction (ATP levels, caspase-8, -9, -3/7 activities) (Luminometry), single strand DNA and nuclear fragmentation (Comet and Hoechst assay). Additionally, relative expression of pro- and anti-apoptotic proteins were determined (Western Blotting). Significant antioxidant depletion was consistent with a concomitant increase in ROS-induced lipid peroxidation and extracellular LDH levels. FA induced apoptosis by significantly increasing Bax expression and caspase-8, -9 and -3/7 activities whilst decreasing ATP levels and Bcl-2 expression. Further, FA significantly increased comet tail lengths, PARP-1 expression and late stage apoptotic body formation in SNO cells. This study shows that FA is cytotoxic and induces increased apoptosis in SNO cells.

Fusaric acid and analogues as Gram-negative bacterial quorum sensing inhibitors

Taking advantage of microwave-assisted synthesis, efficient and expedite procedures for preparation of a library of fusaric acid and 39 analogues are reported. The fusaric acid analogues were tested in cell-based screening assays for inhibition of the las and rhl quorum sensing system in Pseudomonas aeruginosa and the lux quorum sensing system in Vibrio fischeri. Eight of the 40 compounds in the library including fusaric acid inhibited lux quorum sensing and one compound inhibited activity of the las quorum sensing system. To our delight, none of the compounds showed growth inhibitory effects in the tested concentration ranges.

Fusaric acid induces mitochondrial stress in human hepatocellular carcinoma (HepG2) cells

Fusarium spp are common contaminants of maize and produce many mycotoxins, including the fusariotoxin fusaric acid (FA). FA is a niacin related compound, chelator of divalent cations, and mediates toxicity via oxidative stress and possible mitochondrial dysregulation. Sirtuin 3 (SIRT3) is a stress response deacetylase that maintains proper mitochondrial function. We investigated the effect of FA on SIRT3 and oxidative and mitochondrial stress pathways in the hepatocellular carcinoma (HepG2) cell line. We determined FA toxicity (24 h incubation; IC50 = 104 μg/ml) on mitochondrial output, cellular and mitochondrial stress responses, mitochondrial biogenesis and markers of cell death using spectrophotometry, luminometry, qPCR and western blots. FA caused a dose dependent decrease in metabolic activity along with significant depletion of intracellular ATP. FA induced a significant increase in lipid peroxidation, despite up-regulation of the antioxidant transcription factor, Nrf2. FA significantly decreased expression of SIRT3 mRNA with a concomitant decrease in protein expression. Lon protease was also significantly down-regulated. FA induced aberrant mitochondrial biogenesis as evidenced by significantly decreased protein expressions of: PGC-1α, p-CREB, NRF1 and HSP70. Finally, FA activated apoptosis as noted by the significantly increased activity of caspases 3/7 and also induced cellular necrosis. This study provides insight into the molecular mechanisms of FA (a neglected mycotoxin) induced hepatotoxicity.

Determination of oral bioavailability of fusaric acid in male Sprague-Dawley rats

Head and neck squamous cell cancer accounts for 3 % of new cancer cases and 2 % of cancer mortality annually in the United States. Current treatment options for most head and neck cancers continue to be surgical excision with or without radiation, radiation alone, or chemotherapy with radiation depending on location, stage of disease, and patient preference. Fusaric acid (FA) is a novel compound from a novel class of nicotinic acid derivatives that have activity against head and neck squamous cell carcinoma (HNSCC). Although its exact mechanism is still unknown, FA is thought to be active by increasing damage to DNA and preventing its synthesis and repair. The novel mechanism of FA provides an alternative to present therapies, as a single agent whether given parenterally or orally. It has synergy with conventional agents taxol, carboplatin, and erlotinib. In order to determine if FA has reasonable oral bioavailability, we have determined the pharmacokinetics of FA in male Sprague Dawley rats following administration by gavage and by intravenous injection. The bioavailability of FA was sufficient (58 %) to suggest that FA may be viable as an orally administered medication. Despite the encouraging bioavailability of FA, the intravenous (IV) pharmacokinetics suggested non-linear behavior within the IV dose range of 10, 25, and 75 mg/kg. These results demonstrate that further pharmacokinetic and toxicity studies in larger animals such as dogs and non-human primates are warranted.

Fusaric acid, a mycotoxin, and its influence on blood coagulation and platelet function

The current study intended to explore the effect of fusaric acid on blood coagulation including plasma coagulation and platelet aggregation. Fusaric acid exhibited biphasic effects on citrated human plasma recalcification time. At concentrations below 50 ng, fusaric acid decreased the clotting time of plasma dose-dependently from 130 ± 3s control value to 32 ± 3s; however, above 50 ng, fusaric acid increased the clotting time from 32 ± 3s and reached a maximum of 152 s at 100 ng and remained unaltered thereafter for the increased dose of fusaric acid. Fusaric acid without damaging red blood cells and platelets, inhibited agonists such as collagen, ADP, thrombin, and epinephrine-induced aggregation of both platelet-rich plasma (PRP) and washed platelets preparations of human. Interestingly, fusaric acid showed biphasic effects only in thrombin-induced platelet aggregation of washed platelets, and at lower concentration (below 900 ng) it activated platelet aggregation; however, in increased concentration (above 900 ng) it inhibited the platelet aggregation of washed platelets. In addition, fusaric acid also inhibited the agonist ADP-induced platelet aggregation of washed platelet suspension but did not show biphasic effect. Further, fusaric acid did not induce the platelets to generate reactive oxygen species (ROS) that clearly suggests that the induction of platelet function could be the result of the fusaric acid-mediated receptor interaction but not through the morphological shape change.

Characterization of hyperparathyroidism in youth and adolescents: a literature review

OBJECTIVES

To systematically review the preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism in children and adolescents under 20 years of age.

METHODS

We searched PUBMED, Cochrane databases, OVID, Web of Science (SCIE and SSCI), CINAHL, and Health Source: Nursing academic for articles involving surgical management of primary hyperparathyroidism in the pediatric population on 5/2012.

SELECTION CRITERIA

Literature review, database review, and retrospective review studies date were used from 1986 until 2012. Ages ranged for 0-19 years old.

RESULTS

Of the 230 cases of pediatric primary hyperparathyroidism reported since 1987, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and normal parathyroid gland pathology occurred in 80%, 16.5%, 0.9%, and 2.6% respectively. Of the MGHD patients (38 pts), 1/2 (19 pts) of the cases were attributed to MEN I, MEN II, or familial non MEN hyperparathyroidism. Tc(99m)-sestamibi and ultrasound were 86% (37/43) and 74.5% (70/94) sensitive, respectively for localizing parathyroid disease.

CONCLUSIONS

Limited data exists on pediatric and adolescent patients with primary hyperparathyroidism. Sufficient data exists demonstrating single adenomas are most common and young patients are usually more symptomatic than adults. One may conclude that spontaneous primary hyperparathyroidism may be approached and managed similarly to adults. The incidence of primary hyperparathyroidism in this population may be under appreciated and a lower threshold for ordering a screening serum calcium should be considered.

Docking studies and network analyses reveal capacity of compounds from Kandelia rheedii to strengthen cellular immunity by interacting with host proteins during tuberculosis infection

Kandelia rheedii (locally known as Guria or Rasunia), widely found and used in Indian subcontinent, is a well-known herbal cure to tuberculosis. However, neither the mechanism nor the active components of the plant extract responsible for mediating this action has yet been confirmed. Here in this study, molecular interactions of three compounds (emodin, fusaric acid and skyrin) from the plant extract with the host protein targets (casein kinase (CSNK), estrogen receptor (ERBB), dopamine β-hydroxylase (DBH) and glucagon receptor (Gcgr)) has been found. These protein targets are known to be responsible for strengthening cellular immunity against Mycobacteria tuberculosis. The specific interactions of these three compounds with the respective protein targets have been discussed here. The insights from study should further help us designing molecular medicines against tuberculosis.

Inhibition of HIV-1 tat-induced transactivation and apoptosis by the divalent metal chelators, fusaric acid and picolinic acid-implications for HIV-1 dementia

The HIV-1 transactivator protein tat is pivotal to the pathogenesis of AIDS, exerting its effects on both viral and cellular gene expression. The basic structure of tat protein allows it to be secreted by HIV-1 infected cells and penetrate uninfected cells where it elicits its multifunctional biochemical effects. The main function of tat protein is viral transactivation which leads to the upregulation of transcription through complex interactions with RNA and host cell factors. Since HIV-1 has been widely implicated as a causative agent of HIV-1 dementia, the aim of our study was to investigate the ability of two novel metal chelators, fusaric acid (FA) and picolinic acid (PA) to firstly inhibit HIV-1 tat induced transcription and secondly, to minimize its cytotoxic effects as mediated via apoptosis. Biologically active tat protein is not freely available commercially. We therefore had to produce, isolate and purify our own protein. A cell culture system and flow cytometric techniques were used in our study. Exposure of CEM-GFP cells to exogenous recombinant tat protein induced transcription and apoptosis, and both processes were inhibited by FA and PA at concentrations that alone did not induce any cytotoxicity. Our data suggest that FA and PA may have therapeutic potential in the management of HIV-1 dementia.

Knockdown of metallopanstimulin-1 inhibits NF-κB signaling at different levels: the role of apoptosis induction of gastric cancer cells

The ribosomal protein S27 (metallopanstimulin-1, MPS-1) has been reported to be a multifunctional protein, with increased expression in a number of cancers. We reported previously that MPS-1 was highly expressed in human gastric cancer. Knockdown of MPS-1 led to spontaneous apoptosis and repressed proliferation of human gastric cancer cells in vitro and in vivo. However, how does MPS-1 regulate these processes is unclear. Here we performed microarray and pathway analyses to investigate possible pathways involved in MPS-1 knockdown-induced apoptosis in gastric cancer cells. Our results showed that knockdown of MPS-1 inhibited NF-κB activity by reducing phosphorylation of p65 at Ser536 and IκBα at Ser32, inhibiting NF-κB nuclear translocation, and down-regulating its DNA binding activity. Furthermore, data-mining the Gene-Regulatory-Network revealed that growth arrest DNA damage inducible gene 45β (Gadd45β), a direct NF-κB target gene, played a critical role in MPS-1 knockdown-induced apoptosis. Over-expression of Gadd45β inhibited MPS-1 knockdown-induced apoptosis via inhibition of JNK phosphorylation. Taken together, these data revealed a novel pathway, the MPS-1/NF-κB/Gadd45β signal pathway, played an important role in MPS-1 knockdown-induced apoptosis of gastric cancer cells. This study sheds new light on the role of MPS-1/NF-κB in apoptosis and the possible use of MPS-1 targeting strategy in the treatment of gastric cancer.

Role of metalloproteins in the clinical management of head and neck squamous cell carcinoma

Metalloproteins are a group of catalytic proteins, which play significant roles in cell cycle and death. Matrix metalloproteinases (MMPs) are a family of endopeptidases that are capable of digesting extracellular matrix components. They have been implicated in carcinogenesis and recent developments have been made to use MMPs clinically to predict outcomes. In the future, selective inhibition of these proteins and their regulatory pathways may prove useful in anticancer therapeutics. We present a review article on the clinical applications of metalloproteins in head and neck squamous cell carcinoma (HNSCC). Metalopanstimulin is highlighted as a putative metalloprotein of interest for those treating HNSCC. Expression of particular metalloproteins has correlation with lymph node metastasis, tumor invasiveness, and overall prognosis in HNSCC.

Enhanced growth inhibition of squamous cell carcinoma of the head and neck by combination therapy of fusaric acid and paclitaxel or carboplatin

Combination of a single dose of paclitaxel with three different dosages of FA resulted in significant (P<0.001) reductions in cell number from controls, paclitaxel alone, and FA treatments alone at four different time points. Combination of a single dose of carboplatin with three different dosages of FA resulted in significant (P<0.001) reductions in cell number from controls and carboplatin treatment alone at 72 and 96 h. Our data suggest that these combinations may provide an enhanced anti-tumor effect with respect to HNSCC. Since, FA can be administered orally, this regimen may introduce a paradigm change in chemotherapy for HNSCC.

Animal models for the study of squamous cell carcinoma of the upper aerodigestive tract: a historical perspective with review of their utility and limitations. Part A. Chemically-induced de novo cancer, syngeneic animal models of HNSCC, animal models of transplanted xenogeneic human tumors

Understanding the complex histological, genetic and molecular changes that lead to malignant transformation of squamous epithelia of the head and neck will likely guide the development of methods for improved diagnosis, monitoring and treatment of head and neck squamous cell carcinoma (HNSCC). The development and use of animal models that closely mimic the histopathology and molecular pathogenesis of HNSCC in humans would greatly expand the research possibilities and provide a means of testing potential therapeutic agents. However, many available animal models of HNSCC fall short of this objective. In order for investigators to select the appropriate model to answer scientific questions, it is important to understand the benefits and limitations of available animal models for the study of HNSCC. The purpose of this work is to give an overview of the most pertinent animal models of HNSCC, and to discuss future directions of research in this field.

The effect of single agent oral fusaric acid (FA) on the growth of subcuta neously xenografted SCC-1 cells in a nude mouse model

OBJECTIVE

To determine whether oral administration of fusaric acid (FA) inhibits tumor growth in an animal model of head and neck cancer (HNSCC).

DESIGN

In vivo murine model, two arm controlled study.

METHODS

Thirty-eight (38) 5-week-old athymic nude mice were randomly assigned to a fusaric acid treatment group (1 mg/mL) (n = 19) or a sterile saline group (n = 19). A left, lateral flank subcutaneous injection of 2.0 x 10(6) UM-SCC-1 cells were administered to all mice on day 1. Both groups were gavaged daily with either 0.25 mLs of oral FA or sterile saline throughout the experiment (32 days). Latency to a measurable tumor (> or =65 mm3), and tumor volumes were recorded after tumor xenografting. Tumor weights were recorded at the conclusion of the experiment. Tumor volume growth curves were modeled as polynomial functions of time with treatment interaction effects. Survivorship functions for time to measurable tumor were estimated using the Kaplan-Meier product limit estimator.

RESULTS

Survival analysis showed mice treated with FA developed measurable tumors after a significantly longer interval post-xenografting than control mice (p = 0.00451). By Day 9, all mice in the control group had developed measurable tumors in comparison to only 78% of mice in the FA group. Likewise, estimated growth curves for both groups suggested that mice receiving FA demonstrated significantly slower tumor growth rates throughout the entire study period (p < 0.0001). At the conclusion of the experiment, tumor weights from both the control and FA groups were also significantly different (p = 0.0142).

CONCLUSIONS

Single agent oral fusaric acid (1 mg/mL) is an inhibitor of UM-SCC-1 in a murine model. As an orally active agent, it may have a potential role in the treatment of human squamous cell carcinoma of the head and neck.