Antihormonal agents as a strategy to improve the effect of chemo-radiation in cervical cancer: in vitro and in vivo study

Pharmacokinetics and Anti-Tumor Efficacy of PEGylated Liposomes Co-Loaded with Cisplatin and Mifepristone

Although cisplatin is an effective chemotherapy drug used against many types of cancer, it has poor bioavailability, produces severe adverse effects, and frequently leads to tumor resistance. Consequently, more effective formulations are needed. The co-administration of cisplatin with mifepristone, which counters an efflux pump drug-resistance mechanism in tumor cells, has shown important synergism, but without resolving the problem of poor bioavailability. Specificity to tumor tissue and bioavailability have been improved by co-encapsulating cisplatin and mifepristone in a liposomal formulation (L-Cis/MF), which needs further research to complete pre-clinical requirements. The aim of this current contribution was to conduct a pharmacokinetic study of cisplatin and mifepristone in male Wistar rats after administration of L-Cis/MF and the conventional (unencapsulated) formulation. Additionally, the capacity of L-Cis/MF to reduce tumor growth in male nude mice was evaluated following the implantation of xenografts of non-small-cell lung cancer. The better pharmacokinetics (higher plasma concentration) of cisplatin and mifepristone when injected in the liposomal versus the conventional formulation correlated with greater efficacy in controlling tumor growth. Future research on L-Cis/MF will characterize its molecular mechanisms and apply it to other types of cancer affected by the synergism of cisplatin and mifepristone.

Interactions of EGFR/PTEN/mTOR-Pathway Activation and Estrogen Receptor Expression in Cervical Cancer

(1) Objective: Late-line chemotherapy rechallenge in recurrent cervical cancer is associated with modest therapy response but significant side effects. As mTOR pathways modulate cellular growth via estrogen receptor (ER) signaling and combined mTOR and ER inhibition previously demonstrated survival benefits in breast cancer, this exploratory study evaluates mTOR pathway and ER expression interactions in a preclinical cervical cancer model. (2) Methods: Immunostaining of a 126-tumor core tissue microarray was performed to assess phosphorylated-mTOR and ER expression. To identify tumor subsets with different clinical behavior, expression results were matched with clinicopathologic patient characteristics, and both univariate and multivariable survival statistics were performed. (3) Results: phosphorylated-mTOR correlates with ER (r = 0.309, p < 0.001) and loss of PTEN expression (r = -2.09, p = 0.022) in tumor samples across stages but not in matched negative controls. Positive ER expression is observed significantly more often in phosphorylated-mTOR positive samples (30.0% vs. 6.3%, p = 0.001). In the subgroup of phosphorylated-mTOR positive tumors (n = 60), ER expression is associated with improved survival (p = 0.040). (4) Conclusion: ER expression appears closely intertwined with EGFR/PTEN/mTOR-pathway activation and seems to define a subgroup with clinically distinct behavior. Considering limited therapeutic options in recurrent cervical cancer, further validation of combined mTOR and ER inhibition in selected patients could appear promising.

Clinical Update on Uses for Mifepristone in Obstetrics and Gynecology

IMPORTANCE

Mifepristone (RU-486) is a selective progesterone receptor modulator that has antagonist properties on the uterus and cervix. Mifepristone is an effective abortifacient, prompting limitations on its use in many countries. Mifepristone has many uses outside of induced abortion, but these are less well known and underutilized by clinicians because of challenges in accessing and prescribing this medication.

OBJECTIVES

To provide clinicians with a history of the development of mifepristone and mechanism of action and safety profile, as well as detail current research on uses of mifepristone in both obstetrics and gynecology.

EVIDENCE ACQUISITION

A PubMed search of mifepristone and gynecologic and obstetric conditions was conducted between January 2018 and December 2021. Other resources were also searched, including guidelines from the American College of Obstetricians and Gynecologists and the Society of Family Planning.

RESULTS

Mifepristone is approved by the Food and Drug Administration for first-trimester medication abortion but has other off-label uses in both obstetrics and gynecology. Obstetric uses that have been investigated include management of early pregnancy loss, intrauterine fetal demise, treatment of ectopic pregnancy, and labor induction. Gynecologic uses that have been investigated include contraception, treatment of abnormal uterine bleeding, and as an adjunct in treatment of gynecologic cancers.

CONCLUSIONS AND RELEVANCE

Mifepristone is a safe and effective medication both for its approved use in first-trimester medication abortion and other off-label uses. Because of its primary use as an abortifacient, mifepristone is underutilized by clinicians. Providers should consider mifepristone for other indications as clinically appropriate.

N6-methyladenosine modification of CENPK mRNA by ZC3H13 promotes cervical cancer stemness and chemoresistance

BACKGROUND

Stemness and chemoresistance contribute to cervical cancer recurrence and metastasis. In the current study, we determined the relevant players and role of N⁶-methyladenine (m⁶A) RNA methylation in cervical cancer progression.

METHODS

The roles of m⁶A RNA methylation and centromere protein K (CENPK) in cervical cancer were analyzed using bioinformatics analysis. Methylated RNA immunoprecipitation was adopted to detect m⁶A modification of CENPK mRNA. Human cervical cancer clinical samples, cell lines, and xenografts were used for analyzing gene expression and function. Immunofluorescence staining and the tumorsphere formation, clonogenic, MTT, and EdU assays were performed to determine cell stemness, chemoresistance, migration, invasion, and proliferation in HeLa and SiHa cells, respectively. Western blot analysis, co-immunoprecipitation, chromatin immunoprecipitation, and luciferase reporter, cycloheximide chase, and cell fractionation assays were performed to elucidate the underlying mechanism.

RESULTS

Bioinformatics analysis of public cancer datasets revealed firm links between m⁶A modification patterns and cervical cancer prognosis, especially through ZC3H13-mediated m⁶A modification of CENPK mRNA. CENPK expression was elevated in cervical cancer, associated with cancer recurrence, and independently predicts poor patient prognosis [hazard ratio = 1.413, 95% confidence interval = 1.078 - 1.853, P = 0.012]. Silencing of CENPK prolonged the overall survival time of cervical cancer-bearing mice and improved the response of cervical cancer tumors to chemotherapy in vivo (P < 0.001). We also showed that CENPK was directly bound to SOX6 and disrupted the interactions of CENPK with β-catenin, which promoted β-catenin expression and nuclear translocation, facilitated p53 ubiquitination, and led to activation of Wnt/β-catenin signaling, but suppression of the p53 pathway. This dysregulation ultimately enhanced the tumorigenic pathways required for cell stemness, DNA damage repair pathways necessary for cisplatin/carboplatin resistance, epithelial-mesenchymal transition involved in metastasis, and DNA replication that drove tumor cell proliferation.

CONCLUSIONS

CENPK was shown to have an oncogenic role in cervical cancer and can thus serve as a prognostic indicator and novel target for cervical cancer treatment.

Mifepristone Repurposing in Treatment of High-Grade Gliomas

Glioma is the most common and aggressive primary tumor of the central nervous system. The standard treatment for malignant gliomas is surgery followed by chemoradiotherapy. Unfortunately, this treatment has not produced an adequate patient response, resulting in a median survival time of 12–15 months and a 5-year overall survival of <5%. Although new strategies have been sought to enhance patient response, no significant increase in the global survival of glioma patients has been achieved. The option of developing new drugs implies a long and costly process, making drug repurposing a more practical alternative for improving glioma treatment. In the last few years, researchers seeking more effective cancer therapy have pursued the possibility of using anti-hormonal agents, such as mifepristone. The latter drug, an antagonist for progesterone and glucocorticoid receptors, has several attractive features: anti-tumor activity, low cytotoxicity to healthy cells, and modulation of the chemosensitivity of several cancer cell lines in vitro. Hence, the addition of mifepristone to temozolomide-based glioblastoma chemotherapy may lead to a better patient response. The mechanisms by which mifepristone enhances glioma treatment are not yet known. The current review aims to discuss the potential role of mifepristone as an adjuvant drug for the treatment of high-grade gliomas.

Mifepristone as a Potential Therapy to Reduce Angiogenesis and P-Glycoprotein Associated With Glioblastoma Resistance to Temozolomide

Glioblastoma, the most common primary central nervous system tumor, is characterized by extensive vascular neoformation and an area of necrosis generated by rapid proliferation. The standard treatment for this type of tumor is surgery followed by chemotherapy based on temozolomide and radiotherapy, resulting in poor patient survival. Glioblastoma is known for strong resistance to treatment, frequent recurrence and rapid progression. The aim of this study was to evaluate whether mifepristone, an antihormonal agent, can enhance the effect of temozolomide on C6 glioma cells orthotopically implanted in Wistar rats. The levels of the vascular endothelial growth factor (VEGF), and P-glycoprotein (P-gp) were examined, the former a promoter of angiogenesis that facilitates proliferation, and the latter an efflux pump transporter linked to drug resistance. After a 3-week treatment, the mifepristone/temozolomide regimen had decreased the level of VEGF and P-gp and significantly reduced tumor proliferation (detected by PET/CT images based on 18F-fluorothymidine uptake). Additionally, mifepristone proved to increase the intracerebral concentration of temozolomide. The lower level of O6-methylguanine-DNA-methyltransferase (MGMT) (related to DNA repair in tumors) previously reported for this combined treatment was herein confirmed. After the mifepristone/temozolomide treatment ended, however, the values of VEGF, P-gp, and MGMT increased and reached control levels by 14 weeks post-treatment. There was also tumor recurrence, as occurred when administering temozolomide alone. On the other hand, temozolomide led to 100% mortality within 26 days after beginning the drug treatment, while mifepristone/temozolomide enabled 70% survival 60–70 days and 30% survived over 100 days, suggesting that mifepristone could possibly act as a chemo-sensitizing agent for temozolomide.

Liposomes Co-Encapsulating Cisplatin/Mifepristone Improve the Effect on Cervical Cancer: In Vitro and In Vivo Assessment

Cervical cancer is usually diagnosed in the later stages despite many campaigns for early detection and continues to be a major public health problem. The standard treatment is cisplatin-based chemotherapy plus radiotherapy, but patient response is far from ideal. In the research for new drugs that enhance the activity of cisplatin, different therapeutic agents have been tested, among them the antiprogestin mifepristone. Nevertheless, the efficacy of cisplatin is limited by its low specificity for tumor tissue, which causes severe side effects. Additionally, cervical tumors often become drug resistant. These problems could possibly be addressed by the use of liposome nanoparticles to encapsulate drugs and deliver them to the target. The aim of this study was to prepare liposome nanoparticles that co-encapsulate cisplatin and mifepristone, evaluate their cytotoxicity against HeLa cells and in vivo with subcutaneous inoculations of xenografts in nu/nu mice, and examine some plausible mechanisms of action. The liposomes were elaborated by the reverse-phase method and characterized by physicochemical tests. The nanoparticles had a mean particle size of 109 ± 5.4 nm and a Zeta potential of -38.7 ± 1.2 mV, the latter parameter indicating a stable formulation. These drug-loaded liposomes significantly decreased cell viability in vitro and tumor size in vivo, without generating systemic toxicity in the animals. There was evidence of cell cycle arrest and increased apoptosis. The promising results with the co-encapsulation of cisplatin/mifepristone warrant further research.

Targeting Cullin-RING E3 Ligases for Radiosensitization: From NEDDylation Inhibition to PROTACs

As a dynamic regulator for short-lived protein degradation and turnover, the ubiquitin-proteasome system (UPS) plays important roles in various biological processes, including response to cellular stress, regulation of cell cycle progression, and carcinogenesis. Over the past decade, research on targeting the cullin-RING (really interesting new gene) E3 ligases (CRLs) in the UPS has gained great momentum with the entry of late-phase clinical trials of its novel inhibitors MLN4924 (pevonedistat) and TAS4464. Several preclinical studies have demonstrated the efficacy of MLN4924 as a radiosensitizer, mainly due to its unique cytotoxic properties, including induction of DNA damage response, cell cycle checkpoints dysregulation, and inhibition of NF-κB and mTOR pathways. Recently, the PROteolysis TArgeting Chimeras (PROTACs) technology was developed to recruit the target proteins for CRL-mediated polyubiquitination, overcoming the resistance that develops inevitably with traditional targeted therapies. First-in-class cell-permeable PROTACs against critical radioresistance conferring proteins, including the epidermal growth factor receptor (EGFR), androgen receptor (AR) and estrogen receptor (ER), cyclin-dependent kinases (CDKs), MAP kinase kinase 1 (MEK1), and MEK2, have emerged in the past 5 years. In this review article, we will summarize the most important research findings of targeting CRLs for radiosensitization.

Estrogen receptor 1 mutations in 260 cervical cancer samples from Chinese patients

Cervical cancer is one of the leading causes of cancer-associated mortality among females; however, the underlying molecular mechanisms of its carcinogenesis remain largely unclear. Previous comprehensive genomic studies have revealed prevalent estrogen receptor 1 (ESR1) mutations in breast cancer, which are rare in certain other types of cancer. To the best of our knowledge, it is unknown whether ESR1 mutations also exist in cervical cancer. Considering the evidence that cervical cancer shares certain genetic aberrations with breast cancer, and that the progression of both breast and cervical cancers can be affected by estrogen, it is possible that cervical cancer may also harbor ESR1 mutations. In the present study, a total of 260 Chinese cervical cancer samples with distinct subtypes were tested for the presence of ESR1 mutations. A total of three heterozygous missense ESR1 mutations, p.K303R (c.908A>G), p.T311M (c.932C>T) and p.Y537C (c.1610A>G), were identified in 3/207 (1.4%) cervical squamous cell carcinoma samples, which were absent in 27 adenosquamous carcinomas and 26 adenocarcinomas samples. Of the three individuals with an ESR1mutation, 1 patient was also diagnosed with ovarian endometriosis and the other 2 patients were diagnosed with a uterine fibroid. A bioinformatics analysis suggested that these ESR1 mutations may be pathogenic by promoting the development of cervical cancer. Furthermore, a previous comprehensive study confirmed that individuals with cervical squamous cell carcinoma possessed ESR1 mutations. These combined studies indicate that ESR1 mutations may participate in the carcinogenesis of cervical squamous cell carcinoma, albeit at a low frequency. In conclusion, the present study identified three potentially pathogenic ESR1 mutations in Chinese cervical squamous cell carcinoma samples, but not in other subtypes.

CDS-1548 induces apoptosis in HeLa cells by activating caspase 3

Cervical cancer continues to be a threat to female health globally. In the present study, the potential anticancer activity of 2-[2-hydroxyl-1-(4-methoxy phenyl) ethyl]-3-(4-benzyloxy phenyl) isoindolin-1-one (CDS-1548), was evaluated in HeLa cells. CDS-1548 is an organic small-molecule compound characterized by two chiral centers, with the nuclear parent 1H-isoindolin-1-one. CDS-1548 administration significantly elevated the transcriptional activity of p53 and its downstream target genes in a dose-dependent manner. Additionally, CDS-1548 treatment increased the expression levels of p53 and mouse double minute 2 homolog, as well as inducing apoptosis in HeLa cells. Furthermore, CDS-1548 treatment downregulated the expression of B-cell lymphoma 2, upregulated Bcl-2 homologous antagonist killer, promoted the release of cytochrome c from mitochondria to cytoplasm, and activated the production of caspase 3 and 9. Collectively, these results suggested that CDS-1548 inhibited HeLa cell proliferation by promoting G₂/M cell cycle phase arrest and inducting of mitochondria-mediated apoptosis.

Delivery of folic acid-modified liposomal curcumin for targeted cervical carcinoma therapy

Introduction: In this study, novel folic acid (FA)-modified curcumin (CUR) liposomes (LPs) were developed and evaluated for their antitumor activity in vitro and in vivo. Methods: Characterization of the LPs, including transmission electron microscopy, morphology, particle size, and zeta potential studies, was carried out. Drug entrapment efficiency, drug-loading capacity, and release properties in vitro were tested. The in vitro growth inhibition activity, cellular uptake efficiency, and cell apoptosis of FA-modified CUR LPs were also investigated by a cervical cancer HeLa cell model. Results: The optimized distearoyl-l-a-phosphatidylethanolamine (DSPE)-PEG₂₀₀₀-FA-LPs/CUR formed spherical vesicles of nanometer sizes and had particle sizes of 112.3±4.6 nm, polydispersity index of 0.19±0.03, and zeta potential of -15.3±1.4 mV. In addition, the EE% and DL% of (DSPE)-PEG₂₀₀₀-FA-LPs/CUR were 87.6% and 7.9%, respectively. Compared with the free drug, FA-modified CUR LPs had sustained-release properties in vitro. In vivo, a strong green fluorescence was observed in the cytoplasmic region after incubation of (DSPE)-PEG₂₀₀₀-FA-LPs/CUR for 2 hrs. Conclusion: (DSPE)-PEG₂₀₀₀-FA-LPs/CUR showed a superior antiproliferative effect on HeLa cells and had a better antitumor effect in vivo than the non-modified LPs. These results indicated that (DSPE)-PEG₂₀₀₀-FA-LPs/CUR was a promising candidate for antitumor drug delivery.

Cancer of Reproductive System: Receptors and Targeting Strategies

Carcinogenesis in the different organs of the reproductive system, particularly, prostate, ovarian, and cervical tissues, involves aberrant expression of various physiological receptors belonging to different superfamilies. This chapter provides insights into the physiological receptors that are associated with the genesis, progression, metastasis, management, as well as the prognosis of the cancers of the male and female reproductive systems. It also highlights the structural and binding characteristics of the highly predominant receptors, namely, androgen, estrogen, progesterone, and gonadotropin-releasing hormone (GnRH) receptors, which are overexpressed in these cancers and discusses various strategies to target them.

Mifepristone Overcomes Tumor Resistance to Temozolomide Associated with DNA Damage Repair and Apoptosis in an Orthotopic Model of Glioblastoma

The standard treatment for glioblastoma multiforme (GBM) is surgery followed by chemo/radiotherapy. A major limitation on patient improvement is the high resistance of tumors to drug treatment, likely responsible for their subsequent recurrence and rapid progression. Therefore, alternatives to the standard therapy are necessary. The aim of the present study was to evaluate whether mifepristone, an antihormonal agent, has a synergistic effect with temozolomide (used in standard therapy for gliomas). Whereas the mechanism of temozolomide involves damage to tumor DNA leading to apoptosis, tumor resistance is associated with DNA damage repair through the O⁶-methylguanine-DNA-methyltransferase (MGMT) enzyme. Temozolomide/mifepristone treatment, herein examined in Wistar rats after orthotopically implanting C6 glioma cells, markedly reduced proliferation. This was evidenced by a decreased level of the following parameters: a proliferation marker (Ki-67), a tumor growth marker (¹⁸F-fluorothymidine uptake, determined by PET/CT images), and the MGMT enzyme. Increased apoptosis was detected by the relative expression of related proteins, (e.g. Bcl-2 (B-cell lymphoma 2), Bax (bcl-2-like protein 4) and caspase-3). Thus, greater apoptosis of tumor cells caused by their diminished capacity to repair DNA probably contributed significantly to the enhanced activity of temozolomide. The results suggest that mifepristone could possibly act as a chemo-sensitizing agent for temozolomide during chemotherapy for GBM.

Computational repositioning and preclinical validation of mifepristone for human vestibular schwannoma

The computational repositioning of existing drugs represents an appealing avenue for identifying effective compounds to treat diseases with no FDA-approved pharmacotherapies. Here we present the largest meta-analysis to date of differential gene expression in human vestibular schwannoma (VS), a debilitating intracranial tumor, and use these data to inform the first application of algorithm-based drug repositioning for this tumor class. We apply an open-source computational drug repositioning platform to gene expression data from 80 patient tumors and identify eight promising FDA-approved drugs with potential for repurposing in VS. Of these eight, mifepristone, a progesterone and glucocorticoid receptor antagonist, consistently and adversely affects the morphology, metabolic activity, and proliferation of primary human VS cells and HEI-193 human schwannoma cells. Mifepristone treatment reduces VS cell viability more significantly than cells derived from patient meningiomas, while healthy human Schwann cells remain unaffected. Our data recommend a Phase II clinical trial of mifepristone in VS.

Estrogen Receptor Signaling in Radiotherapy: From Molecular Mechanisms to Clinical Studies

Numerous studies have established a proof of concept that abnormal expression and function of estrogen receptors (ER) are crucial processes in initiation and development of hormone-related cancers and also affect the efficacy of anti-cancer therapy. Radiotherapy has been applied as one of the most common and potent therapeutic strategies, which is synergistic with surgical excision, chemotherapy and targeted therapy for treating malignant tumors. However, the impact of ionizing radiation on ER expression and ER-related signaling in cancer tissue, as well as the interaction between endocrine and irradiation therapy remains largely elusive. This review will discuss recent findings on ER and ER-related signaling, which are relevant for cancer radiotherapy. In addition, we will summarize pre-clinical and clinical studies that evaluate the consequences of anti-estrogen and irradiation therapy in cancer, including emerging studies on head and neck cancer, which might improve the understanding and development of novel therapeutic strategies for estrogen-related cancers.

The role of calgranulin B gene on the biological behavior of squamous cervical cancer in vitro and in vivo

Objective

The objective of the study was to explore the role of calgranulin B gene on the biological behavior of squamous cervical cancer.

Methods

Differential transcription in calgranulin B gene between human papillomavirus (HPV)-positive and negative cervical cancer groups was identified, and the relationship between calgranulin B gene and matrix metalloproteinase (MMP) genes were explored using The Cancer Genome Atlas database. Subsequently, the role of calgranulin B on the cell proliferation, apoptosis, invasion and migration was investigated, through overexpression and/or underexpression of calgranulin B in cervical cancer cells. In addition, the effect of calgranulin B on the growth of the cervical cancer was studied via constructing xenograft model in BALB/c nude mice that either overexpressed or underexpressed calgranulin B.

Results

Calgranulin B gene transcription in cervical cancer was highly correlated with the high-risk HPV-16 and HPV-45. In addition, overexpression of calgranulin B increased cell proliferation, invasion and migration, whereas it did not significantly affect cell apoptosis. This effect was also confirmed by calgranulin B knockdown assay. Additionally, we found that the transcription of calgranulin B gene was negatively correlated with MMP15 and MMP24 genes, but positively associated with MMP25 genes in cervical cancer. Furthermore, calgranulin B significantly promoted the growth of cervical cancer in vivo.

Conclusion

Calgranulin B promotes cell proliferation, migration and invasion of squamous cervical cancer, possibly via regulation of MMPs. Whether there are synergistic actions between calgranulin B and HPV-16/HPV-45 infection on the squamous cervical carcinogenesis or progression need further study.

Effect of Curcumin-Nanoemulsion Associated with Photodynamic Therapy in Cervical Carcinoma Cell Lines

Cervical cancer is the fourth cause of cancer death in women. Curcumin has antineoplastic properties. Furthermore, curcumin may be used as a photosensitizing agent in Photodynamic Therapy. This study aimed to investigate the effects of Photodynamic Therapy in cellular viability using curcumin-nanoemulsion as a photosensitizing drug in cervical carcinoma cell lines. The empty nanoemulsion presented very low cytotoxicity in all cell lines analyzed. Additionally, the incubation with curcumin-nanoemulsion at 20 μM of curcumin showed more than 80% of cell viability for cell lines. Nanoemulsions were shown to be internalized inside cells by fluorescence microscopy and were observed in the intracellular environment for up to 36 hours after incubation with cell lines. In addition, after the Photodynamic Therapy we observed a high phototoxic effect of the curcumin-nanoemulsion with less than 5% of viable cells after irradiation. This was accompanied by an increase in caspase-3/caspase-7 activities after cell treatment with curcumin-nanoemulsion and Photodynamic Therapy, suggesting cell death by apoptosis. We conclude that the curcumin-nanoemulsion formulation behaves as a photosensitizing drug in Photodynamic Therapy and shows potential as an alternative treatment to cervical lesions using an endoscopic diode fiber laser setup for in situ activation or cavity activation using a diffuse fiber delivery system.

Chemotherapy with cisplatin: insights into intracellular pH and metabolic landscape of cancer cells in vitro and in vivo

Although cisplatin plays a central role in cancer chemotherapy, the mechanisms of cell response to this drug have been unexplored. The present study demonstrates the relationships between the intracellular pH (pHi), cell bioenergetics and the response of cervical cancer to cisplatin. pHi was measured using genetically encoded sensor SypHer2 and metabolic state was accessed by fluorescence intensities and lifetimes of endogenous cofactors NAD(P)H and FAD. Our data support the notion that cisplatin induces acidification of the cytoplasm early after the treatment. We revealed in vitro that a capacity of cells to recover and maintain alkaline pHi after the initial acidification is the crucial factor in mediating the cellular decision to survive and proliferate at a vastly reduced rate or to undergo cell death. Additionally, we showed for the first time that pHi acidification occurs after prolonged therapy in vitro and in vivo, and this, likely, favors metabolic reorganization of cells. A metabolic shift from glycolysis towards oxidative metabolism accompanied the cisplatin-induced inhibition of cancer cell growth in vitro and in vivo. Overall, these findings contribute to an understanding of the mechanisms underlying the responsiveness of an individual cell and tumor to therapy and are valuable for developing new therapeutic strategies.

Synergic Effect of α-Mangostin on the Cytotoxicity of Cisplatin in a Cervical Cancer Model

Cervical cancer is the second leading cause of death among Mexican women. The treatment with cis-diamminedichloroplatinum (II) (CDDP) has some serious side effects. Alpha-mangostin (α-M), has a protective effect against CDDP-induced nephrotoxicity, as well as antioxidant, antitumor, and anti-inflammatory properties. Hence, we explored the in vitro and in vivo effect of α-M on human cervical cancer cell proliferation when combined with CDDP. In vitro, The cytotoxic effect of α-M and/or CDDP was measured by the 3-(3,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium assay. Meanwhile, apoptosis, reactive oxygen species (ROS) production, and the cell cycle were determined with flow cytometry. For α-M+CDDP treatment, both a coincubation and preincubation scheme were employed. In vivo, xenotransplantation was performed in female athymic BALB/c (nu/nu) mice, and then tumor volume and body weight were measured weekly, whereas α-M interfered with the antiproliferative activity of CDDP in the coincubation scheme, with preincubation with α-M+CDDP showing significantly greater cytotoxicity than CDDP or α-M alone, significantly inhibiting average tumor volume and preventing nephrotoxicity. This effect was accompanied by increased apoptosis and ROS production by HeLa cervical cancer cells, as well as an arrest in the cell cycle. These results suggest that α-M may be useful as a neoadjuvant agent in cervical cancer therapy.

Vorinostat enhances the cisplatin-mediated anticancer effects in small cell lung cancer cells

BACKGROUND

Vorinostat, a histone deacetylase (HDAC) inhibitor, is a promising agent for cancer therapy. Combining vorinostat with cisplatin may relax the chromatin structure and facilitate the accessibility of cisplatin, thus enhancing its cytotoxicity. Studies have not yet investigated the effects of the combination of vorinostat and cisplatin on small cell lung cancer (SCLC).

METHODS

We first assessed the efficacy of vorinostat with etoposide/cisplatin (EP; triple combination) and then investigated the effects of cotreatment with vorinostat and cisplatin on H209 and H146 SCLC cell lines. The anticancer effects of various combinations were determined in terms of cell viability, apoptosis, cell cycle distribution, and vorinostat-regulated proteins. We also evaluated the efficacy of vorinostat/cisplatin combination in H209 xenograft nude mice.

RESULTS

Our data revealed that the triple combination engendered a significant reduction of cell viability and high apoptotic cell death. In addition, vorinostat combined with cisplatin enhanced cell growth inhibition, induced apoptosis, and promoted cell cycle arrest. We observed that the acetylation levels of histone H3 and α-tubulin were higher in combination treatments than in vorinostat treatment alone. Moreover, vorinostat reduced the expression of thymidylate synthase (TS), and TS remained inhibited after cotreament with cisplatin. Furthermore, an in vivo study revealed that the combination of vorinostat and cisplatin significantly inhibited tumor growth in xenograft nude mice (tumor growth inhibition T/C% = 20.5 %).

CONCLUSIONS

Combined treatments with vorinostat promote the cytotoxicity of cisplatin and induce the expression of vorinostat-regulated acetyl proteins, eventually enhancing antitumor effects in SCLC cell lines. Triple combinations with a low dosage of cisplatin demonstrate similar therapeutic effects. Such triple combinations, if applied clinically, may reduce the undesired adverse effects of cisplatin. The effects of the combination of vorinostat and cisplatin should be evaluated further before conducting clinical trials for SCLC treatment.

Molecular mechanisms of cisplatin resistance in cervical cancer

Patients with advanced or recurrent cervical cancer have poor prognosis, and their 1-year survival is only 10%–20%. Chemotherapy is considered as the standard treatment for patients with advanced or recurrent cervical cancer, and cisplatin appears to treat the disease effectively. However, resistance to cisplatin may develop, thus substantially compromising the efficacy of cisplatin to treat advanced or recurrent cervical cancer. In this article, we systematically review the recent literature and summarize the recent advances in our understanding of the molecular mechanisms underlying cisplatin resistance in cervical cancer.