Anti-tumour activity of CS-7017, a selective peroxisome proliferator-activated receptor gamma agonist of thiazolidinedione class, in human tumour xenografts and a syngeneic tumour implant model

Thiazolidinedione derivatives in cancer therapy: exploring novel mechanisms, therapeutic potentials, and future horizons in oncology

Thiazolidinedione derivatives have shown significant potential as targeted cancer therapies by leveraging their various mechanisms of action. These include suppressing cell proliferation, triggering apoptosis, and influencing signaling pathways associated with tumor development. Their multifaceted effects make them promising candidates for advancing cancer treatment strategies. They have shown significant promise as anti-cancer agents, particularly through their ability to inhibit lipogenesis pathways and apoptosis essential for cancer cell survival and proliferation. This review comprehensively examines the anti-cancer potential of thiazolidinedione derivatives by targeting key aspects of lipid metabolism, apoptosis, and various mechanistic pathways. This review provides an in-depth examination of the anti-cancer potential of TZD derivatives, focusing on their mechanisms of action, therapeutic applications, and future directions in oncology. The anti-tumor effects of TZDs primarily involve the stimulation of peroxisome proliferator-activated receptor gamma (PPAR-γ), suppressing cell proliferation, induction of apoptosis, and inhibition of angiogenesis. Moreover, recent evidence highlights their ability to modulate non-PPAR-γ pathways, such as PI3K/Akt, NF-κB, and MAPK, further expanding their role in overcoming drug resistance and enhancing therapeutic outcomes. This review explores the preclinical (in vitro and in vivo) and clinical research investigating TZD derivatives efficacy in various cancer types. The insights underscore the significance of targeting lipogenesis as a novel anti-cancer strategy, positioning thiazolidinedione derivatives as potent candidates for future cancer therapeutics. As the oncology landscape evolves, TZD derivatives (rosiglitazone, pioglitazone, inolitazone, troglitazone, and 2,4-thiazolidinedione derivatives) represent a promising class of agents with the potential to contribute meaningfully to cancer treatment. By integrating existing knowledge with recent advancements, this study provides valuable insights into the role of thiazolidinedione derivatives in cancer treatment, paving the way for further research and clinical applications.

Discovery of cloxiquine derivatives as potent HDAC inhibitors for the treatment of melanoma via activating PPARγ

The combined treatment with histone deacetylase (HDAC) inhibitors with peroxisome proliferator-activated receptor γ (PPARγ) agonists has displayed significant anticancer efficacy. Based on these results, a series of cloxiquine derivatives were prepared as potent HDAC inhibitors for the treatment of melanoma. Among these compounds, CS4 exhibited excellent inhibitory effects on HDAC1 (IC50 = 38 nM) and HDAC6 (IC50 = 12 nM), and had good antiproliferative effects against A375 and SK-MEL-5 melanoma cells (IC50 values, 1.20 and 0.93 μM, respectively). Mechanism research indicated that CS4 inhibited SK-MEL-5 cell growth by promoting α-tubulin and histone 3 (H3) acetylation. At the metabolic level, treatment with BG11 activated PPARγ and blocked glycolysis in SK-MEL-5 cells, which mediated partial antimelanoma effects of CS4. In addition, CS4 also induced cell cycle arrest at G2, suppressed migration and facilitated apoptosis of SK-MEL-5 cells. More importantly, compound CS4 demonstrated significant in vivo anticancer effect compared with SAHA, and exhibited neglectable toxicity. Consequently, CS4 is the potent HDAC inhibitor, which may be developed as the candidate antimelanoma drug.

Combined In Silico and In Vitro Analyses to Assess the Anticancer Potential of Thiazolidinedione-Thiosemicarbazone Hybrid Molecules

The number of people affected by cancer and antibiotic-resistant bacterial infections has increased, such that both diseases are already seen as current and future leading causes of death globally. To address this issue, based on a combined in silico and in vitro approach, we explored the anticancer potential of known antibacterials with a thiazolidinedione-thiosemicarbazone (TZD-TSC) core structure. A cytotoxicity assessment showed encouraging results for compounds 2-4, with IC50 values against T98G and HepG2 cells in the low micromolar range. TZD-TSC 3 proved to be most toxic to cancer cell lines, with IC50 values of 2.97 ± 0.39 µM against human hepatoma HepG2 cells and IC50 values of 28.34 ± 2.21 µM against human glioblastoma T98G cells. Additionally, compound 3 induced apoptosis and showed no specific hemolytic activity. Furthermore, treatment using 3 on cancer cell lines alters these cells' morphology and further suppresses migratory activity. Molecular docking, in turn, suggests that 3 would have the capacity to simultaneously target HDACs and PPARγ, by the activation of PPARγ and the inhibition of both HDAC4 and HDAC8. Thus, the promising preliminary results obtained with TZD-TSC 3 represent an encouraging starting point for the rational design of novel chemotherapeutics with dual antibacterial and anticancer activities.

Transcription Factors: The Fulcrum Between Cell Development and Carcinogenesis

Higher eukaryotic development is a complex and tightly regulated process, whereby transcription factors (TFs) play a key role in controlling the gene regulatory networks. Dysregulation of these regulatory networks has also been associated with carcinogenesis. Transcription factors are key enablers of cancer stemness, which support the maintenance and function of cancer stem cells that are believed to act as seeds for cancer initiation, progression and metastasis, and treatment resistance. One key area of research is to understand how these factors interact and collaborate to define cellular fate during embryogenesis as well as during tumor development. This review focuses on understanding the role of TFs in cell development and cancer. The molecular mechanisms of cell fate decision are of key importance in efforts towards developing better protocols for directed differentiation of cells in research and medicine. We also discuss the dysregulation of TFs and their role in cancer progression and metastasis, exploring TF networks as direct or indirect targets for therapeutic intervention, as well as specific TFs' potential as biomarkers for predicting and monitoring treatment responses.

Thiazolidinedione "Magic Bullets" Simultaneously Targeting PPARγ and HDACs: Design, Synthesis, and Investigations of their In Vitro and In Vivo Antitumor Effects

Monotargeting anticancer agents suffer from resistance and target nonspecificity concerns, which can be tackled with a multitargeting approach. The combined treatment with HDAC inhibitors and PPARγ agonists has displayed potential antitumor effects. Based on these observations, this work involves design and synthesis of molecules that can simultaneously target PPARγ and HDAC. Several out of 25 compounds inhibited HDAC4, and six compounds acted as dual-targeting agents. Compound 7i was the most potent, with activity toward PPARγ EC50 = 0.245 μM and HDAC4 IC50 = 1.1 μM. Additionally, compounds 7c and 7i were cytotoxic to CCRF-CEM cells (CC50 = 2.8 and 9.6 μM, respectively), induced apoptosis, and caused DNA fragmentation. Furthermore, compound 7c modulated the expression of c-Myc, cleaved caspase-3, and caused in vivo tumor regression in CCRF-CEM tumor xenografts. Thus, this study provides a basis for the rational design of dual/multitargeting agents that could be developed further as anticancer therapeutics.

Design, synthesis, and molecular docking studies of thiazolidinediones as PPAR-γ agonists and thymidylate synthase inhibitors

New thiazolidine-2,4-dione hybrids were designed and synthesized as potential peroxisome proliferator-activated receptor (PPAR)-γ agonists and thymidylate synthase inhibitors. All the synthesized compounds follow Lipinski's and Veber's rules and possess the desired pharmacokinetics properties. The PPAR-γ transactivation results displayed that compounds 12 (78.9%) and 11 (73.4%) were the most active compounds and they increased PPAR-γ gene expression by 2.2- and 2.4-fold, respectively. Compounds 12, 11, and 8 showed promising cytotoxicity, with IC₅₀ values ranging from 1.4 to 4.5 μM against MCF-7 cells and from 1.8 to 8.4 μM against HCT-116 cells. Compounds 11 and 12 also inhibited thymidylate synthase with IC₅₀ values of 5.1 and 3.2 μM, respectively, confirming their mode of action as thymidylate synthase inhibitors. Finally, molecular docking studies supported the in vitro biological activity results.

PPARγ in Ischemia-Reperfusion Injury: Overview of the Biology and Therapy

Ischemia-reperfusion injury (IRI) is a complex pathophysiological process that is often characterized as a blood circulation disorder caused due to various factors (such as traumatic shock, surgery, organ transplantation, burn, and thrombus). Severe metabolic dysregulation and tissue structure destruction are observed upon restoration of blood flow to the ischemic tissue. Theoretically, IRI can occur in various tissues and organs, including the kidney, liver, myocardium, and brain, among others. The advances made in research regarding restoring tissue perfusion in ischemic areas have been inadequate with regard to decreasing the mortality and infarct size associated with IRI. Hence, the clinical treatment of patients with severe IRI remains a thorny issue. Peroxisome proliferator-activated receptor γ (PPARγ) is a member of a superfamily of nuclear transcription factors activated by agonists and is a promising therapeutic target for ameliorating IRI. Therefore, this review focuses on the role of PPARγ in IRI. The protective effects of PPARγ, such as attenuating oxidative stress, inhibiting inflammatory responses, and antagonizing apoptosis, are described, envisaging certain therapeutic perspectives.

Design, synthesis and in vitro antiproliferative activity of new thiazolidinedione-1,3,4-oxadiazole hybrids as thymidylate synthase inhibitors

Thymidylate synthase (TS) has been an attention-grabbing area of research for the treatment of cancers due to their role in DNA biosynthesis. In the present study, we have synthesised a library of thiazolidinedione-1,3,4-oxadiazole hybrids as TS inhibitors. All the synthesised hybrids followed Lipinski and Veber rules which indicated good drug likeness properties upon oral administration. Among the synthesised hybrids, compound 9 and 10 displayed 4.5 and 4.4 folds activity of 5-Fluorouracil, respectively against MCF-7 cell line whereas 3.1 and 2.5 folds cytotoxicity against HCT-116 cell line. Furthermore, compound 9 and 10 also inhibited TS enzyme with IC50 = 1.67 and 2.21 µM, respectively. Finally, the docking studies of 9 and 10 were found to be consistent with in vitro TS results. From these studies, compound 9 and 10 has the potential to be developed as TS inhibitors.

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

We report a new synthetic approach to assemble spirothiazolidinediones via a [2 + 2 + 2] cyclotrimerization reaction and the derivatives were further functionalized through DA chemistry and click reaction. Using flow cytometry, it was shown for the first time that the new benzyl alcohol derivatives of thiazolidine-2,4-dione generated here are efficient apoptosis inducers in the HeLa, Hek293, U937, Jurkat, and K562 cell lines.

Development of a novel class of peroxisome proliferator-activated receptor (PPAR) gamma ligands as an anticancer agent with a unique binding mode based on a non-thiazolidinedione scaffold

We previously identified dibenzooxepine derivative 1 as a potent PPARγ ligand with a unique binding mode owing to its non-thiazolidinedione scaffold. However, while 1 showed remarkably potent MKN-45 gastric cancer cell aggregation activity, an indicator of cancer differentiation-inducing activity induced by PPARγ activation, we recognized that 1 was metabolically unstable. In the present study, we identified a metabolically soft spot, and successfully discovered 3-fluoro dibenzooxepine derivative 9 with better metabolic stability. Further optimization provided imidazo[1,2-a]pyridine derivative 17, which showed potent MKN-45 gastric cancer cell aggregation activity and excellent PK profiles compared with 9. Compound 17 exerted a growth inhibitory effect on AsPC-1/AG1 pancreatic tumor in mice. Furthermore, the decrease in the hematocrit (an indicator of localized edema, a serious adverse effect of PPARγ ligands) was tolerable even with oral administration at 200 mg/kg in healthy mice.

Association between colorectal cancer and thiazolidinediones administration in a case-control study

OBJECTIVES

This study was designed to assess whether there was an association between colorectal cancer and thiazolidinediones use.

METHODS

A population-based case-control study was performed using the database of the Taiwan National Health Insurance Program. The case group consisted of 20218 type 2 diabetic subjects aged 20 to 84 years with newly diagnosed colorectal cancer between 2000 and 2011. The date of a subject being diagnosed with colorectal cancer was defined as the index date. The control group consisted of 20218 randomly selected type 2 diabetic subjects aged 20 to 84 years without colorectal cancer between 2000 and 2011. A subject who had at least a prescription of thiazolidinediones before the index date was defined as "ever used". A subject who did not have a prescription of thiazolidinediones before the index date was defined as "never used". The odds ratio (OR) and 95% confidence interval (CI) was used to estimate the association between colorectal cancer and thiazolidinediones use by the multivariable logistic regression model.

RESULTS

After adjustment for potential confounders, the odds of thiazolidinediones use in cases with colorectal cancer were lower than the odds of thiazolidinediones use in subjects without colorectal cancer (adjusted OR 0.94, 95% CI 0.89-0.99).

CONCLUSIONS

The odds of thiazolidinediones use in cases with colorectal cancer were lower than subjects without colorectal cancer. A prospective study is required to test whether thiazolidinediones use has a protective effect against colorectal cancer.

Clinical Trials in Management of Anaplastic Thyroid Carcinoma; Progressions and Set Backs: A Systematic Review

CONTEXT

Anaplastic thyroid carcinoma (ATC) is associated with rapid tumor growth and extremely poor prognosis. Although ATC is found in only 2% of all thyroid carcinomas, it accounts for up to 50% of thyroid cancer mortality.

OBJECTIVE

To understand the effect of different treatment modalities upon anaplastic thyroid cancer outcomes.

METHODS

A systematic review of studies from 1995 to 2017 was performed employing the search terms "anaplastic thyroid" and "treatment" in PubMed. Studies comparing patients receiving any type of therapy for ATC and measuring either survival as primary outcome or the percentage of patient surviving more than 1 year as secondary outcome were included for review. We did not limit sample size or subject condition. A total of 40 articles were returned from our database search, of which 25 met the inclusion criteria.

RESULTS

A review of the 25 published studies indicated that early multidisciplinary approaches using extensive radical surgery, in combination with adjuvant chemo-radiation using either docetaxel/pacitaxel or cisplatin, provided the best chance of disease control. Targeted multi-tyrosine kinases inhibitors helped to limit disease progression. Also, the finding of foci of differentiated thyroid cancer within the anaplastic tumor was associated with increased long-term survival.

CONCLUSIONS

ATC remains a fatal disease. Despite aggressive therapy the median survival has not significantly changed over the last 20 years. However, the percentage of patients surviving longer than 1 year continues to increase. Novel approaches incorporating multiple targeted therapy and immune therapies are critically needed.

Combined PPARγ Activation and XIAP Inhibition as a Potential Therapeutic Strategy for Ovarian Granulosa Cell Tumors

Ovarian granulosa cell tumors (GCT) are characterized by indolent growth and late relapse. No therapeutic modalities aside from surgery have proven effective. We previously reported overexpression of the nuclear receptor, peroxisome proliferator-activated receptor-gamma (PPARγ), and constitutive activity of the NFκB and AP1 signaling pathways in GCT. PPARγ presents as a potential therapeutic target as it impedes proliferation and promotes terminal differentiation of granulosa cells. However, resistance to the actions of PPARγ is caused by NFκB transrepression in GCT-derived cell lines, KGN and COV434. We showed that abrogation of NFκB signaling in GCT cells enables PPARγ agonists to initiate apoptosis. In addition, we observed overexpression of an NFκB-induced gene, X-linked inhibitor of apoptosis protein (XIAP), in GCT and GCT-derived cells. XIAP is an attractive therapeutic target due to its role in inhibiting the apoptotic pathway. We investigated the antitumor effects of combined XIAP inhibition using Smac-mimetics and PPARγ activation using thiazolidinediones (TZD) in the GCT-derived cells. Transactivation assays revealed that NFκB transrepression of PPARγ can be relieved by NFκB or XIAP inhibition. Combined Smac-mimetic and TZD significantly induced apoptosis, reduced cell viability and proliferation in KGN cells in monolayer and 3D spheroid culture, and in GCT explant models. The Smac-mimetic and TZD cotreatment also delayed cell invasion, upregulated proapoptotic genes, and compromised cell metabolism in KGN cells. This study provides evidence that PPARγ and XIAP cotreatment has antineoplastic effects in GCT. As therapeutics that target these proteins are already in clinical or preclinical use, expedient translation to the clinic is possible.

Development of Dihydrodibenzooxepine Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands of a Novel Binding Mode as Anticancer Agents: Effective Mimicry of Chiral Structures by Olefinic E/ Z-Isomers

A novel class of PPARγ ligand 1 (EC₅₀ = 197 nM) with a dibenzoazepin scaffold was identified through high-throughput screening campaign. To avoid the synthetically troublesome chiral center of 1, its conformational analysis using the MacroModel was conducted, focusing on conformational flip of the tricyclic ring and the conformational restriction by the methyl group at the chiral center. On the basis of this analysis, scaffold hopping of dibenzoazepine into dibenzo[ b, e]oxepine by replacing the chiral structures with the corresponding olefinic E/ Z isomers was performed. Consequently, dibenzo[ b, e]oxepine scaffold 9 was developed showing extremely potent PPARγ reporter activity (EC₅₀ = 2.4 nM, efficacy = 9.5%) as well as differentiation-inducing activity against a gastric cancer cell line MKN-45 that was more potent than any other well-known PPARγ agonists in vitro (94% at 30 nM). The X-ray crystal structure analysis of 9 complexed with PPARγ showed that it had a unique binding mode to PPARγ ligand-binding domain that differed from that of any other PPARγ agonists identified thus far.

Identification of a Novel PPAR-γ Agonist through a Scaffold Tuning Approach

Peroxisome proliferator-activated receptors (PPARs) are important targets in metabolic diseases including obesity, metabolic syndrome, diabetes, and non-alcoholic fatty liver disease. Recently, they have been highlighted as attractive targets for the treatment of cardiovascular diseases and chronic myeloid leukemia. The PPAR agonist structure is consists of a polar head, a hydrophobic tail, and a linker. Each part interacts with PPARs through hydrogen bonds or hydrophobic interactions to stabilize target protein conformation, thus increasing its activity. Acidic head is essential for PPAR agonist activity. The aromatic linker plays an important role in making hydrophobic interactions with PPAR as well as adjusting the head-to-tail distance and conformation of the whole molecule. By tuning the scaffold of compound, the whole molecule could fit into the ligand-binding domain to achieve proper binding mode. We modified indol-3-ylacetic acid scaffold to (indol-1-ylmethyl)benzoic acid, whereas 2,4-dichloroanilide was fixed as the hydrophobic tail. We designed, synthesized, and assayed the in vitro activity of novel indole compounds with (indol-1-ylmethyl)benzoic acid scaffold. Compound 12 was a more potent PPAR-γ agonist than pioglitazone and our previous hit compound. Molecular docking studies may suggest the binding between compound 12 and PPAR-γ, rationalizing its high activity.

Discovery of DS-6930, a potent selective PPARγ modulator. Part I: Lead identification

The lead identification of a novel potent selective PPARγ agonist, DS-6930 is reported. To avoid PPARγ-related adverse effects, a partial agonist was designed to prevent the direct interaction with helix 12 of PPARγ-LBD. Because the TZD group is known to interact with helix 12, the TZD in efatutazone (CS-7017) was replaced to discover novel PPARγ intermediate partial agonist 8i. The optimization of 8i yielded 13ac with high potency in vitro. Compound 13ac exhibited robust plasma glucose lowering effects comparable to those of rosiglitazone (3 mg/kg) in Zucker diabetic fatty rats. Upon toxicological evaluation, compound 13ac (300 mg/kg) induced hemodilution to a lower extent than rosiglitazone; however, 13ac elevated liver enzyme activities. X-ray crystallography revealed no direct interaction of 13ac with helix 12, and the additional lipophilic interactions are also suggested to be related to the maximum transcriptional activity of 13ac.

Impact of Concurrent Medication Use on Pancreatic Cancer Survival-SEER-Medicare Analysis

OBJECTIVES

Preclinical studies have suggested that non-antineoplastic medication use may impact pancreatic cancer biology. We examined the association of several medication classes on pancreatic cancer survival in a large medical claims database.

MATERIALS AND METHODS

Histologically confirmed pancreatic adenocarcinoma diagnosed between 2006 and 2009 were analyzed from the Surveillance, Epidemiology, and End Results-Medicare database with available part D data. Drug use was defined as having 2 prescriptions filled within 12 months of pancreatic cancer diagnosis. The following medication classes/combinations were analyzed: β-blocker, statin, insulin, metformin, thiazolidinedione, warfarin, heparin, β-blocker/statin, metformin/statin, and β-blocker/metformin. Multivariable Cox proportional hazard models adjusting for age, sex, race, stage at diagnosis, site of cancer, and Charlson comorbidity index were constructed to test the association between medication classes and overall survival.

RESULTS

A total of 13,702 patients were included in the study; median age 76 years, 42.5% males, 77.1% white. The most common anatomic site and stage at diagnosis were head of the pancreas (49.9%) and stage 4 (49.6%), respectively. Ninety-four percent of patients died in the follow-up period (median overall survival 5.3 mo). Multivariable Cox regression analysis showed that use of β-blockers, heparin, insulin, and warfarin were significantly associated with improved survival (P<0.05 for each one), whereas metformin, thiazolidinedione, statin, and combination therapies were not.

CONCLUSIONS

In this study, use of β-blockers, heparin, insulin, and warfarin were associated with improved survival in patients with pancreatic cancer. Additional studies are needed to validate these findings in the clinical setting.

The Opportunities and Challenges of Peroxisome Proliferator-Activated Receptors Ligands in Clinical Drug Discovery and Development

Peroxisome proliferator-activated receptors (PPARs) are a well-known pharmacological target for the treatment of multiple diseases, including diabetes mellitus, dyslipidemia, cardiovascular diseases and even primary biliary cholangitis, gout, cancer, Alzheimer's disease and ulcerative colitis. The three PPAR isoforms (α, β/δ and γ) have emerged as integrators of glucose and lipid metabolic signaling networks. Typically, PPARα is activated by fibrates, which are commonly used therapeutic agents in the treatment of dyslipidemia. The pharmacological activators of PPARγ include thiazolidinediones (TZDs), which are insulin sensitizers used in the treatment of type 2 diabetes mellitus (T2DM), despite some drawbacks. In this review, we summarize 84 types of PPAR synthetic ligands introduced to date for the treatment of metabolic and other diseases and provide a comprehensive analysis of the current applications and problems of these ligands in clinical drug discovery and development.

Biotinylation enhances the anticancer effects of 15d‑PGJ2 against breast cancer cells

15-Deoxy-∆12,14-prostaglandin J2 (15d‑PGJ2) is a natural agonist of peroxisome proliferator-activated receptor γ (PPARγ) that displays anticancer activity. Various studies have indicated that the effects of 15d‑PGJ2 are due to both PPARγ-dependent and -independent mechanisms. In the present study, we examined the effects of a biotinylated form of 15d‑PGJ2 (b‑15d‑PGJ2) on hormone-dependent MCF‑7 and triple‑negative MDA‑MB‑231 breast cancer cell lines. b‑15d‑PGJ2 inhibited cell proliferation more efficiently than 15d‑PGJ2 or the synthetic PPARγ agonist, efatutazone. b‑15d‑PGJ2 was also more potent than its non-biotinylated counterpart in inducing apoptosis. We then analyzed the mechanisms underlying this improved efficiency. It was found not to be the result of biotin receptor-mediated increased incorporation, since free biotin in the culture medium did not decrease the anti-proliferative activity of b‑15d‑PGJ2 in competition assays. Of note, b‑15d‑PGJ2 displayed an improved PPARγ agonist activity, as measured by transactivation experiments. Molecular docking analyses revealed a similar insertion of b‑15d‑PGJ2 and 15d‑PGJ2 into the ligand binding domain of PPARγ via a covalent bond with Cys285. Finally, PPARγ silencing markedly decreased the cleavage of the apoptotic markers, poly(ADP-ribose) polymerase 1 (PARP‑1) and caspase‑7, that usually occurs following b‑15d‑PGJ2 treatment. Taken together, our data indicate that biotinylation enhances the anti-proliferative and pro-apoptotic activity of 15d‑PGJ2, and that this effect is partly mediated via a PPARγ-dependent pathway. These results may aid in the development of novel therapeutic strategies for breast cancer treatment.

The angiotensin II type 1 receptor antagonist telmisartan inhibits cell proliferation and tumor growth of esophageal adenocarcinoma via the AMPKα/mTOR pathway in vitro and in vivo

Telmisartan, a widely used antihypertensive drug, is an angiotensin II type 1 (AT1) receptor blocker (ARB). This drug inhibits cancer cell proliferation, but the underlying mechanisms in various cancers, including esophageal cancer, remain unknown. The aim of the present study was to evaluate the effects of telmisartan on human esophageal cancer cell proliferation in vitro and in vivo. We assessed the effects of telmisartan on human esophageal adenocarcinoma (EAC) cells using the cell lines OE19, OE33, and SKGT-4. Telmisartan inhibited the proliferation of these three cell lines via blockade of the G₀ to G₁ cell cycle transition. This blockade was accompanied by a strong decrease in cyclin D1, cyclin E, and other cell cycle-related proteins. Notably, the AMP-activated protein kinase (AMPK) pathway, a fuel sensor signaling pathway, was enhanced by telmisartan. Compound C, which inhibits the two catalytic subunits of AMPK, enhanced the expression of cyclin E, leading to G₀/G₁ arrest in human EAC cells. In addition, telmisartan reduced the phosphorylation of epidermal growth factor receptor (p-EGFR) and ERBB2 in vitro. In our in vivo study, intraperitoneal injection of telmisartan led to a 73.2% reduction in tumor growth in mice bearing xenografts derived from OE19 cells. Furthermore, miRNA expression was significantly altered by telmisartan in vitro and in vivo. In conclusion, telmisartan suppressed human EAC cell proliferation and tumor growth by inducing cell cycle arrest via the AMPK/mTOR pathway.

The PPARγ agonist efatutazone delays invasive progression and induces differentiation of ductal carcinoma in situ

PURPOSE

Ductal carcinoma in situ (DCIS) is a pre-invasive lesion of the breast considered a precursor of invasive ductal carcinoma. This study aimed to determine whether activated PPARγ acts as a tumor suppressor in human DCIS progression.

METHODS

We utilized the high-affinity PPARγ agonist, efatutazone, to activate endogenous PPARγ in a well-defined model for the progression of basal (triple negative) DCIS, MCFDCIS cells, cultured under 2D and 3D conditions. We studied the effects of activated PPARγ on DCIS progression in MCFDCIS xenograft and C3(1)/Tag transgenic mice treated with 30 mg/kg of efatutazone.

RESULTS

In vitro, efatutazone did not alter the MCFDCIS cell proliferation but induced phenotypic and gene expression changes, indicating that activated PPARγ is able to differentiate MCFDCIS cells into more luminal and lactational-like cells. In addition, MCFDCIS tumorsphere formation in 3D was reduced by PPARγ activation. In vivo, efatutazone-treated MCFDCIS tumors exhibited fat deposition along with upregulation of PPARγ responsive genes in both epithelial and stromal compartments, suggesting features of milk-producing mammary epithelial cell differentiation. The efatutazone-treated lesions were less invasive with fewer CD44+/p63+ basal progenitor cells. PPARγ activation downregulated Akt phosphorylation in these tumors, although the ERK pathway remained unchanged. Similar trends in gene expression changes consistent with lactational and luminal cell differentiation were observed in the C3(1)/Tag mouse model after efatutazone treatment.

CONCLUSIONS

Our data suggest that activation of the PPARγ pathway differentiates DCIS lesions and may be a useful approach to delay DCIS progression.

RP-HPTLC Data in Correlation Studies of a 5-Arylidene-2,4-Thiazolidinedione Derivatives

Thiazolidinediones show a large scale of biological activities as a result of ability to perform interactions with a variety of biological targets. Modeling properties of newly synthesized thiazolidinediones is important for both understanding their activity and predicting their interactions. In the paper the chromatographic retention data determined in various RP chromatographic systems (stationary phases RP-CN and RP-18; six aqueous binary mobile phases modified with acetonitrile, methanol, ethanol, propanol, acetone and dioxane) were considered for 13 new 5-arylidene-2,4-thiazolidinediones. In this article, three attempts to find suitable quantitative structure-retention relationship (QSRR) models that quantify retention as a function ofmolecular descriptors had been presented. Models built for RP-18 show generally better multiple R but are also mostly monoparametric with logP as the dominant descriptor. More informative from the standpoint of molecular interactions are QSRR models for RP-CN. The quality of those models depends of the mobile phase modifier (the best was obtained for acetone and the worst for propanol as modifier). Since all QSRR models use extrapolated retention as a property which is indirectly connected with plasma protein binding further assessment of plasma protein binding should be based on extrapolated retention on a RP-CN stationary phase instead of standard RP-18.

Cytotoxic effects of 15-deoxy-Δ12,14-prostaglandin J2 alone and in combination with dasatinib against uterine sarcoma in vitro

Effective chemotherapeutic strategies for uterine sarcoma are lacking; existing therapies achieve poor response rates. Previous studies have identified the prostaglandin 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) as a potential anticancer treatment; however, its effectiveness in uterine sarcoma has not been examined. Furthermore, the molecular mechanisms underlying the cytotoxic mechanism of 15d-PGJ2 remain unclear. Here, we evaluated the effects of 15d-PGJ2 alone and in combination with the tyrosine kinas inhibitor (TKI) dasatinib in uterine sarcoma cell lines (MES-SA, MES-SA/DX5 and SKN). 15d-PGJ2 inhibited cell growth and increased apoptosis. Western blotting demonstrated that 15d-PGJ2 treatment increased MEK and ERK phosphorylation, and decreased levels of phosphorylated AKT. Dasatinib in combination with 15d-PGJ2 significantly reduced cell proliferation compared with 15d-PGJ2 alone, and repressed both the AKT and MAPK pathways. The cell growth inhibition rate in the PGJ2 was 21.5±12.0, 35.3±5.4 and 28.3±4.2%, respectively (MES-SA, MES-SA/DX5 and SKN cell lines) and the cell growth inhibition rate in the combination therapy was significantly higher compared with 15d-PGJ2 alone (MES-SA; 64.2±0.8, MES-SA/DX5;23.9±8.2 and SKN; 41.4±17.6%). The PGJ2 IC₅₀ determined by MTT assay was 27.41,10.46 and 17.38 µmol/l, respectively (MES-SA, MES-SA/DX5 and SKN cell lines) and the dasatinib IC₅₀ was 6.68,17.30 and 6.25 µmol/l, respectively. Our findings demonstrate that 15d-PGJ2 suppresses proliferation by inactivating the AKT pathway in uterine sarcoma. Furthermore, combining 15d-PGJ2 with dasatinib produced a synergistic effect on cancer cell inhibition by repressing 15d-PGJ2-mediated activation of MAPK signaling, and further repressing AKT signaling. These results suggest that 15d-PGJ2 could be used in combination with dasatinib as a potential therapeutic approach for uterine sarcoma.

A Metabolic Inhibitory Cocktail for Grave Cancers: Metformin, Pioglitazone and Lithium Combination in Treatment of Pancreatic Cancer and Glioblastoma Multiforme

Pancreatic cancer (PC) and glioblastoma multiforme (GBM) are among the human cancers with worst prognosis which require an urgent need for efficient therapies. Here, we propose to apply to treat both malignancies with a triple combination of drugs, which are already in use for different indications. Recent studies demonstrated a considerable link between risk of PC and diabetes. In experimental models, anti-diabetogenic agents suppress growth of PC, including metformin (M), pioglitazone (P) and lithium (L). L is used in psychiatric practice, yet also bears anti-diabetic potential and selectively inhibits glycogen synthase kinase-3 beta (GSK-3β). M, a biguanide class anti-diabetic agent shows anticancer activity via activating AMP-activated protein kinase (AMPK). Glitazones bind to PPAR-γ and inhibit NF-κB, triggering cell proliferation, apoptosis resistance and synthesis of inflammatory cytokines in cancer cells. Inhibition of inflammatory cytokines could simultaneously decrease tumor growth and alleviate cancer cachexia, having a major role in PC mortality. Furthermore, mutual synergistic interactions exist between PPAR-γ and GSK-3β, between AMPK and GSK-3β and between AMPK and PPAR-γ. In GBM, M blocks angiogenesis and migration in experimental models. Very noteworthy, among GBM patients with type 2 diabetes, usage of M significantly correlates with better survival while reverse is true for sulfonylureas. In experimental models, P synergies with ligands of RAR, RXR and statins in reducing growth of GBM. Further, usage of P was found to be lesser in anaplastic astrocytoma and GBM patients, indicating a protective effect of P against high-grade gliomas. L is accumulated in GBM cells faster and higher than in neuroblastoma cells, and its levels further increase with chronic exposure. Recent studies revealed anti-invasive potential of L in GBM cell lines. Here, we propose that a triple-agent regime including drugs already in clinical usage may provide a metabolic adjuvant therapy for PC and GBM.

Anaplastic thyroid cancer

PURPOSE OF REVIEW

Anaplastic thyroid cancer (ATC) is a rare malignancy of the thyroid with a high mortality rate. Conventional therapy has not been effective. Several biological agents are being investigated. The purpose of the review is to highlight the current standards for treatment and review new targets for treating ATC.

RECENT FINDINGS

Retrospective studies have led to formulation of guidelines for management, including those by the American Thyroid Association. An expansion in the understanding of the genetic mutations has led to several newer biological agents being tested to treat ATC. Aurora kinase inhibitors, PPAR γ agonists, and vascular targeting agents are some of the latest therapeutic agents that have shown promise and could become standard of therapy with further supporting research.

SUMMARY

Further well coordinated preclinical and clinical research is needed to support the emerging treatments for ATC.

Chemotherapy and chemoprevention by thiazolidinediones

Thiazolidinediones (TZDs) are synthetic ligands of Peroxisome-Proliferator-Activated Receptor gamma (PPARγ). Troglitazone, rosiglitazone, and pioglitazone have been approved for treatment of diabetes mellitus type II. All three compounds, together with the first TZD ciglitazone, also showed an antitumor effect in preclinical studies and a beneficial effect in some clinical trials. This review summarizes hypotheses on the role of PPARγ in tumors, on cellular targets of TZDs, antitumor effects of monotherapy and of TZDs in combination with other compounds, with a focus on their role in the treatment of differentiated thyroid carcinoma. The results of chemopreventive effects of TZDs are also considered. Existing data suggest that the action of TZDs is highly complex and that actions do not correlate with cellular PPARγ expression status. Effects are cell-, species-, and compound-specific and concentration-dependent. Data from human trials suggest the efficacy of TZDs as monotherapy in prostate cancer and glioma and as chemopreventive agent in colon, lung, and breast cancer. TZDs in combination with other therapies might increase antitumor effects in thyroid cancer, soft tissue sarcoma, and melanoma.

Antihyperglycaemic therapies and cancer risk

AIMS

This review is aimed at highlighting the potential mitogenic/tumour growth-promoting or antimitogenic/tumour growth-inhibiting effects of the main antihyperglycaemic drug classes.

METHODS

We review and discuss the most current studies evaluating the association between antidiabetic medications used in clinical practice and malignancies as described so far.

RESULTS

Metformin seems to be the only antidiabetic drug to exert protective effects both on monotherapy and also when combined with other oral antidiabetic drugs or insulins in several site-specific cancers. In contrast, several other drug classes may increase cancer risk. Some reason for concern remains regarding sulphonylureas and also the incretin-based therapies regarding pancreas and thyroid cancers and the sodium glucose cotransporter-2 inhibitors as well as pioglitazone regarding bladder cancer. The majority of meta-analyses suggest that there is no evidence for a causal relationship between insulin glargine and elevated cancer risk, although the studies have been controversially discussed. For α-glucosidase inhibitors and glinides, neutral or only few data upon cancer risk exist.

CONCLUSION

Although the molecular mechanisms are not fully understood, a potential risk of mitogenicity and tumour growth promotion cannot be excluded in case of several antidiabetic drug classes. However, more large-scale, randomized, well-designed clinical studies with especially long follow-up time periods are needed to get reliable answers to these safety issues.

Peroxisome proliferator-activated receptor γ agonist efatutazone impairs transforming growth factor β2-induced motility of epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancer cells

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are effective for non-small cell lung cancers (NSCLC) with EGFR-activating mutations. However, most responders develop resistance. Efatutazone, a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is currently under clinical evaluation; it has antiproliferative effects and induces cellular morphological changes and differentiation. The present study investigated the effects of efatutazone in EGFR-TKI-resistant NSCLC cells, while focusing on cell motility. The PC-9-derived NSCLC cell lines PC-9ER and PC-9ZD, resistant to EGFR-TKI due to v-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) amplification-induced phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT) activation and an EGFR T790M mutation, respectively, were used. These cells exhibit enhanced cell motility due to transforming growth factor β (TGF-β)/Smad2 family member 2 (Smad2) pathway activation. Efatutazone had no growth-inhibitory effect on the tested cells but inhibited the motility of EGFR-TKI-resistant cells in wound closure and transwell assays. Efatutazone plus erlotinib treatment provided greater inhibition of PC-9ER cell migration than efatutazone or erlotinib alone. Efatutazone suppressed increased TGF-β2 secretion from both cell lines (shown by ELISA) and downregulation of TGF-β2 transcription (observed by quantitative RT-PCR). Immunoblot analysis and luciferase assays revealed that efatutazone suppressed Smad2 phosphorylation and its transcriptional activity. These results suggest that efatutazone inhibits cell motility by antagonizing the TGF-β/Smad2 pathway and effectively prevents metastasis in NSCLC patients with acquired resistance to EGFR-TKI regardless of the resistance mechanism.

Phase 1 study of efatutazone, a novel oral peroxisome proliferator-activated receptor gamma agonist, in combination with FOLFIRI as second-line therapy in patients with metastatic colorectal cancer

Background Efatutazone, a novel oral highly-selective peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has demonstrated some inhibitory effects on disease stabilization in patients with metastatic colorectal cancer (mCRC) enrolled in previous phase I studies. Here, we evaluate the safety and pharmacokinetics of efatutazone combined with FOLFIRI (5-fluorouracil, levo-leucovorin, and irinotecan) as second-line chemotherapy in Japanese patients with mCRC. Methods Dose-limiting toxicities (DLTs) were evaluated at 2 efatutazone dose levels of 0.25 and 0.50 mg (the recommended dose [RD] of efatutazone monotherapy) twice daily in combination with FOLFIRI in a 3–9 patient cohort. Furthermore, tolerability at the RD level was assessed in additional patients, up to 12 in total. Blood samples for pharmacokinetics and biomarkers and tumor samples for archival tissues were collected from all patients. Results Fifteen patients (0.25 mg, 3; 0.5 mg, 12) were enrolled. No DLTs were observed. Most patients experienced weight increase (100 %) and edema (80.0 %), which were manageable with diuretics. Common grade 3/4 toxicities were neutropenia (93.3 %), leukopenia (46.7 %), and anemia (33.3 %). Stable disease was observed in 8 of the 14 patients evaluable for tumor response. The plasma adiponectin levels increased over time and increased dose. No clear relationship was detected between treatment efficacies and plasma levels of adiponectin as well as the expression levels of PPARγ and the retinoid X receptor in tumor tissues. Conclusions Efatutazone combined with FOLFIRI demonstrates an acceptable safety profile and evidence of disease stabilization in Japanese patients with mCRC. The RD for efatutazone monotherapy can be used in combination with FOLFIRI.

Small molecule agonists of PPAR-γ exert therapeutic effects in esophageal cancer

The transcription factor PPAR-γ plays various roles in lipid metabolism, inflammation, cellular differentiation, and apoptosis. PPAR-γ agonists used to treat diabetes may have utility in cancer treatment. Efatutazone is a novel later generation PPAR-γ agonist that selectively activates PPAR-γ target genes and has antiproliferative effects in a range of malignancies. In this study, we investigated PPAR-γ status in esophageal squamous cell carcinoma (ESCC) and investigated the antiproliferative effects of efatutazone. PPAR-γ was expressed heterogeneously in ESCC, in which it exhibited an inverse relationship with Ki-67 expression. PPAR-γ expression was associated independently with good prognosis in ESCC. Efatutazone, but not the conventional PPAR-γ agonist troglitazone, inhibited ESCC cell proliferation in vitro and in vivo. Mechanistic investigations suggested that efatutazone acted by upregulating p21Cip1 protein in the nucleus through inactivation of the Akt pathway and dephosphorylation of p21Cip1 at Thr145 without affecting the transcriptional activity of p21Cip1. We also found that treatment with efatutazone led to phosphorylation of the EGF receptor and activation of the mitogen-activated protein kinase (MAPK) pathway. Accordingly, the combination of efatutazone with the antiepithelial growth factor receptor antibody cetuximab synergized to negatively regulate the phosphoinositide 3-kinase-Akt and MAPK pathways. Together, our results suggest that efatutazone, alone or in combination with cetuximab, may offer therapeutic effects in ESCC.

Efatutazone, an oral PPAR-γ agonist, in combination with paclitaxel in anaplastic thyroid cancer: results of a multicenter phase 1 trial

PURPOSE

A phase 1 study was initiated to determine the safety, potential effectiveness, and maximal tolerated dose and recommended phase 2 dose of efatutazone and paclitaxel in anaplastic thyroid cancer.

EXPERIMENTAL DESIGN

Patients received efatutazone (0.15, 0.3, or 0.5 mg) orally twice daily and then paclitaxel every 3 weeks. Patient tolerance and outcomes were assessed, as were serum efatutazone pharmacokinetics.

RESULTS

Ten of 15 patients were women. Median age was 59 years. Seven patients received 0.15 mg of efatutazone, 6 patients received 0.3 mg, and 2 patients received 0.5 mg. One patient receiving 0.3 mg of efatutazone had a partial response from day 69 to day 175; 7 patients attained stable disease. Median times to progression were 48 and 68 days in patients receiving 0.15 mg of efatutazone and 0.3 mg of efatutazone, respectively; corresponding median survival was 98 vs 138 days. The median peak efatutazone blood level was 8.6 ng/mL for 0.15-mg dosing vs 22.0 ng/mL for 0.3-mg twice daily dosing. Ten patients had grade 3 or greater adverse events (Common Terminology Criteria for Adverse Events), with 2 of these (anemia and edema) related to efatutazone. Thirteen events of edema were reported in 8 patients, with 2 of grade 3 or greater. Eight patients had ≥1 serious adverse event, with 1 of these (anemia) attributed to efatutazone and 1 (anaphylactic reaction) related to paclitaxel. The maximal tolerated dose was not achieved. Angiopoietin-like 4 was induced by efatutazone in tissue biopsy samples of 2 patients.

CONCLUSIONS

Efatutazone and paclitaxel in combination were safe and tolerated and had biologic activity.

The PPARγ agonist efatutazone increases the spectrum of well-differentiated mammary cancer subtypes initiated by loss of full-length BRCA1 in association with TP53 haploinsufficiency

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have anticancer activity and influence cell differentiation. We examined the impact of the selective PPARγ agonist efatutazone on mammary cancer pathogenesis in a mouse model of BRCA1 mutation. Mice with conditional loss of full-length BRCA1 targeted to mammary epithelial cells in association with germline TP53 insufficiency were treated with efatutazone through the diet starting at age 4 months and were euthanized at age 12 months or when palpable tumor reached 1 cm(3). Although treatment did not reduce percentage of mice developing invasive cancer, it significantly reduced prevalence of noninvasive cancer and total number of cancers per mouse and increased prevalence of well-differentiated cancer subtypes not usually seen in this mouse model. Invasive cancers from controls were uniformly estrogen receptor α negative and undifferentiated, whereas well-differentiated estrogen receptor α-positive papillary invasive cancers appeared in efatutazone-treated mice. Expression levels of phosphorylated AKT and CDK6 were significantly reduced in the cancers developing in efatutazone-treated mice. Efatutazone treatment reduced rates of mammary epithelial cell proliferation and development of hyperplastic alveolar nodules and increased expression levels of the PPARγ target genes Adfp, Fabp4, and Pdhk4 in preneoplastic mammary tissue. Intervention efatutazone treatment in mice with BRCA1 deficiency altered mammary cancer development by promoting development of differentiated invasive cancer and reducing prevalence of noninvasive cancer and preneoplastic disease.

Correlation between activation of PPARγ and resistin downregulation in a mouse adipocyte cell line by a series of thiazolidinediones

The present study shows significant correlations between the EC50 for PPARγ activation in a reporter gene cell line and resistin downregulation in mouse adipocytes, and between the IC50 for resistin downregulation and the already published minimum effective dose for antihyperglycemic activity in a mouse model. These correlations indicate that PPARγ mediated downregulation of resistin might promote insulin sensitivity and that downregulation of resistin in mouse adipocytes provides an adequate and possibly more direct bioassay for screening of newly developed antihyperglycemic compounds. Because of the higher throughput of the PPARγ the resistin downregulation assays seems most suitable to be used as a second tier in a tiered screening strategy.

Thiazolidine-2,4-diones: progress towards multifarious applications

The promising activity shown by compounds containing thiazolidine-2,4-dione nucleus in numerous categories such as anti-hyperglycaemics, aldose reductase inhibitors, anti-cancer, anti-inflammatory, anti-arthritics, anti-microbials, etc. has made it an indispensable anchor for development of new therapeutic agents. Varied substituents on the thiazolidine-2,4-dione nucleus have provided a wide spectrum of biological activities. Importance of this nucleus in some activities like, peroxisome proliferator activated receptor γ (PPARγ) agonism and PPARγ-dependent and -independent anti-cancer activities are reviewed separately in literature. Short reviews on biological importance of this nucleus are also known in literature. However, owing to fast development of new drugs possessing thiazolidine-2,4-dione nucleus many research reports are generated in short span of time. So, there is a need to couple the latest information with the earlier information to understand the current status of thiazolidine-2,4-dione nucleus in medicinal chemistry research. In the present review, various derivatives of thiazolidine-2,4-diones with different pharmacological activities are described on the basis of substitution pattern around the nucleus combined with the docking studies performed in the active site of the corresponding receptors with an aim to help medicinal chemists for developing an SAR on thiazolidine-2,4-dione derived compounds for each activity. This discussion will further help in the development of novel thiazolidine-2,4-dione compounds.

A phase 1 study of efatutazone, an oral peroxisome proliferator-activated receptor gamma agonist, administered to patients with advanced malignancies

BACKGROUND

Efatutazone (CS-7017), a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, exerts anticancer activity in preclinical models. The authors conducted a phase 1 study to determine the recommended phase 2 dose, safety, tolerability, and pharmacokinetics of efatutazone.

METHODS

Patients with advanced solid malignancies and no curative therapeutic options were enrolled to receive a given dose of efatutazone, administered orally (PO) twice daily for 6 weeks, in a 3 + 3 intercohort dose-escalation trial. After the third patient, patients with diabetes mellitus were excluded. Efatutazone dosing continued until disease progression or unacceptable toxicity, with measurement of efatutazone pharmacokinetics and plasma adiponectin levels.

RESULTS

Thirty-one patients received efatutazone at doses ranging from 0.10 to 1.15 mg PO twice daily. Dose escalation stopped when maximal impact on PPARγ-related biomarkers had been reached before any protocol-defined maximum-tolerated dose level. On the basis of a population pharmacokinetic/pharmacodynamic analysis, the recommended phase 2 dose was 0.5 mg PO twice daily. A majority of patients experienced peripheral edema (53.3%), often requiring diuretics. Three episodes of dose-limiting toxicities, related to fluid retention, were noted in the 0.10-, 0.25-, and 1.15-mg cohorts. Of 31 treated patients, 27 were evaluable for response. A sustained partial response (PR; 690 days on therapy) was observed in a patient with myxoid liposarcoma. Ten additional patients had stable disease (SD) for ≥60 days. Exposures were approximately dose proportional, and adiponectin levels increased after 4 weeks of treatment at all dose levels. Immunohistochemistry of archived specimens demonstrated that PPARγ and retinoid X receptor expression levels were significantly greater in patients with SD for ≥60 days or PR (P = .0079), suggesting a predictive biomarker.

CONCLUSIONS

Efatutazone demonstrates acceptable tolerability with evidence of disease control in patients with advanced malignancies.

Thyroid cancer: pathogenesis and targeted therapy

Therapeutic options for advanced, unresectable radioiodine-resistant thyroid cancers have historically been limited. Recent progress in understanding the pathogenesis of the various subtypes of thyroid cancer has led to increased interest in the development of targeted therapies, with potential strategies including angiogenesis inhibition, inhibition of aberrant intracellular signaling in the MAPK and PI3K/AKT/mTOR pathways, radioimmunotherapy, and redifferentiation agents. On the basis of a recent positive phase III clinical trial, the RET, vascular endothelial growth factor receptor (VEGFR), and epidermal growth factor receptor (EGFR) inhibitor vandetanib has received FDA approval as of April 2011 for use in the treatment of advanced medullary thyroid cancer. Several other recent phase II clinical trials in advanced thyroid cancer have demonstrated significant activity, and multiple other promising therapeutic strategies are in earlier phases of clinical development. The recent progress in targeted therapy is already revolutionizing management paradigms for advanced thyroid cancer, and will likely continue to dramatically expand treatment options in the coming years.

In vivo effects of rosiglitazone in a human neuroblastoma xenograft

BACKGROUND

Neuroblastoma (NB) is the most common extra-cranial solid tumour in infants. Unfortunately, most children present with advanced disease and have a poor prognosis. There is in vitro evidence that the peroxisome proliferator-activated receptor gamma (PPARgamma) might be a target for pharmacological intervention in NB. We have previously demonstrated that the PPARgamma agonist rosiglitazone (RGZ) exerts strong anti-tumoural effects in the human NB cell line, SK-N-AS. The aim of this study was to evaluate whether RGZ maintains its anti-tumoural effects against SK-N-AS NB cells in vivo.

METHODS AND RESULTS

For this purpose, tumour cells were subcutaneously implanted in nude mice, and RGZ (150 mg kg(-1)) was administered by gavage daily for 4 weeks. At the end of treatment, a significant tumour weight inhibition (70%) was observed in RGZ-treated mice compared with control mice. The inhibition of tumour growth was supported by a strong anti-angiogenic activity, as assessed by CD-31 immunostaining in tumour samples. The number of apoptotic cells, as determined by cleaved caspase-3 immunostaining, seemed lower in RGZ-treated animals at the end of the treatment period than in control mice, likely because of the large tumour size observed in the latter group.

CONCLUSIONS

To our knowledge, this is the first demonstration that RGZ effectively inhibits tumour growth in a human NB xenograft and our results suggest that PPARgamma agonists may have a role in anti-tumoural strategies against NB.