Effect of troglitazone on radiation sensitivity in cervix cancer cells

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.

Peroxisome proliferator-activated receptors as therapeutic target for cancer

Peroxisome proliferator-activated receptors (PPARs) are transcription factors belonging to the nuclear receptor family. There are three subtypes of PPARs, including PPAR-α, PPAR-β/δ and PPAR-γ. They are expressed in different tissues and act by regulating the expression of target genes in the form of binding to ligands. Various subtypes of PPAR have been shown to have significant roles in a wide range of biological processes including lipid metabolism, body energy homeostasis, cell proliferation and differentiation, bone formation, tissue repair and remodelling. Recent studies have found that PPARs are closely related to tumours. They are involved in cancer cell growth, angiogenesis and tumour immune response, and are essential components in tumour progression and metastasis. As such, they have become a target for cancer therapy research. In this review, we discussed the current state of knowledge on the involvement of PPARs in cancer, including their role in tumourigenesis, the impact of PPARs in tumour microenvironment and the potential of using PPARs combinational therapy to treat cancer by targeting essential signal pathways, or as adjuvants to boost the effects of current chemo and immunotherapies. Our review highlights the complexity of PPARs in cancer and the need for a better understanding of the mechanism in order to design effective cancer therapies.

PPAR-γ Modulators as Current and Potential Cancer Treatments

Worldwide, cancer has become one of the leading causes of mortality. Peroxisome Proliferator-Activated Receptors (PPARs) is a family of critical sensors of lipids as well as regulators of diverse metabolic pathways. They are also equipped with the capability to promote eNOS activation, regulate immunity and inflammation response. Aside from the established properties, emerging discoveries are also made in PPAR's functions in the cancer field. All considerations are given, there exists great potential in PPAR modulators which may hold in the management of cancers. In particular, PPAR-γ, the most expressed subtype in adipose tissues with two isoforms of different tissue distribution, has been proven to be able to inhibit cell proliferation, induce cell cycle termination and apoptosis of multiple cancer cells, promote intercellular adhesion, and cripple the inflamed state of tumor microenvironment, both on transcriptional and protein level. However, despite the multi-functionalities, the safety of PPAR-γ modulators is still of clinical concern in terms of dosage, drug interactions, cancer types and stages, etc. This review aims to consolidate the functions of PPAR-γ, the current and potential applications of PPAR-γ modulators, and the challenges in applying PPAR-γ modulators to cancer treatment, in both laboratory and clinical settings. We sincerely hope to provide a comprehensive perspective on the prospect of PPAR-γ applicability in the field of cancer treatment.

PPARγ Agonists in Combination Cancer Therapies

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a nuclear receptor acting as a transcription factor involved in the regulation of energy metabolism, cell cycle, cell differentiation, and apoptosis. These unique properties constitute a strong therapeutic potential that place PPARγ agonists as one of the most interesting and widely studied anticancer molecules. Although PPARγ agonists exert significant, antiproliferative and tumoricidal activity in vitro, their anticancer efficacy in animal models is ambiguous, and their effectiveness in clinical trials in monotherapy is unsatisfactory. However, due to pleiotropic effects of PPARγ activation in normal and tumor cells, PPARγ ligands interact with many antitumor treatment modalities and synergistically potentiate their effectiveness. The most spectacular example is a combination of PPARγ ligands with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). In this setting, PPARγ activation sensitizes leukemic stem cells, resistant to any previous form of treatment, to targeted therapy. Thus, this combination is believed to be the first pharmacological therapy able to cure CML patients. Within the last decade, a significant body of data confirming the benefits of the addition of PPARγ ligands to various antitumor therapies, including chemotherapy, hormonotherapy, targeted therapy, and immunotherapy, has been published. Although the majority of these studies have been carried out in vitro or animal tumor models, a few successful attempts to introduce PPARγ ligands into anticancer therapy in humans have been recently made. In this review, we aim to summarize shines and shadows of targeting PPARγ in antitumor therapies.

Rosiglitazone enhances radiosensitivity by inhibiting repair of DNA damage in cervical cancer cells

Radiation therapy (RT) is one of the main treatment modalities for cervical cancer. Rosiglitazone (ROSI) has been reported to have antiproliferative effects against various types of cancer cells and also to induce antioxidant enzymes that can scavenge reactive oxygen species (ROS) and thereby modify radiosensitivity. Here, we explored the effect of ROSI on radiosensitivity and the underlying mechanisms in cervical cancer cells. Three cervical cancer cell lines (ME-180, HeLa, and SiHa) were used. The cells were pretreated with ROSI and then irradiated. Expression of proteins of interest was detected by western blot and immunofluorescence. Intracellular production of ROS was measured by H₂DCFDA. Radiosensitivity was assessed by monitoring clonogenic survival. Expression of antioxidant enzymes (catalase, superoxide dismutases) was increased by ROSI in HeLa and SiHa cells, but not in ME-180 cells. With ROSI pre-treatment, cell survival after irradiation remained unchanged in HeLa and SiHa cells, but decreased in ME-180 cells. Radiation-induced expression of γ-H2AX was increased and that of RAD51 was decreased by ROSI pre-treatment in ME-180 cells, but not in HeLa cells. ROSI increases radiosensitivity by inhibiting RAD51-mediated repair of DNA damage in some cervical cancer cell lines; therefore, ROSI is a potential inhibitor of RAD51 that can be used to enhance the effect of RT in the treatment of some cervical cancers.

Novel agents and treatment techniques to enhance radiotherapeutic outcomes in carcinoma of the uterine cervix

BACKGROUND

Survival of patients with locally advanced carcinoma cervix (LACC) using the current standard of concurrent chemo-radiotherapy (CCRT) has reached a plateau over the last two decades. Loco-regional failure in first two years of treatment completion and distant metastasis in the subsequent years has put the survival curves at a halt. Strategies of induction and adjuvant chemotherapy have yielded little as has any advancement in techniques of delivery of radiation therapy. This article aims at discussing the current existing literature as well as promising novel strategies to enhance radiotherapeutic outcomes in carcinoma of the uterine cervix.

METHODS

The review of English literature included phase I-III trials evaluating either a novel agent, novel application/modifications of an existing treatment regimen or an innovative treatment technique. The studies have been divided in to subsections with summary of most important findings at the end of each section.

RESULTS

Despite CCRT being the 'gold standard' treatment, several issues like optimum drug combination, schedule of drug delivery, combination with molecular targeted agents etc. remain undefined. Taxane, topoisomerase and gemcitabine based regimen needs to be further explored and compared with cisplatin based CCRT regimen. Several approaches like local delivery of cytotoxic agents, use of nano-medicine with CCRT are appearing on horizon with promises for the future. Therapies need to be designed based on the human papillomavirus titers of the patients and incorporation of radiosensitizers as an effective way of palliation with short course of radiotherapy may further enhance the radiotherapeutic outcomes.

CONCLUSIONS

The results of the studies with novel agents and treatment techniques appear promising. Further research in this arena including incorporation of cost-effectiveness analysis and quality of life issues in future trial designs are warranted.

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.