Biological and chemical inhibitors of NF-kappaB sensitize SiHa cells to cisplatin-induced apoptosis

Oxymatrine induces apoptosis in non-small cell lung cancer cells by downregulating TRIM46

Sophora flavescens Aiton, a traditional Chinese medicine that was supposed to predominantly play an anti-inflammatory role, has been used to treat multiple diseases, including cancer, for over two thousand years. Recently, it has attracted increasing attention due to the anti-tumor properties of Oxymatrine, one of the most active alkaloids extracted from S. flavescens. This study aims to explore it's anti-tumor effects in non-small cell lung cancer (NSCLC) and the underlying mechanisms. We first investigated the effects of oxymatrine on cell apoptosis in lung cancer cell lines A549 and PC9 as well as explored related genes in regulating the apoptosis by transcriptome analysis. Subsequently, to further study the role of TRIM46, we constructed two types of TRIM46 over-expression cells (A549TRIM46+ and PC9TRIM46+ cells) and then investigated the effect of TRIM46 on oxymatrine-induced apoptosis. Moreover, we explored the effect of TRIM46 on downstream signaling pathways. Transcriptome analysis suggested that shared differentially expressed genes (DEGs) in A549 and PC9 cells treated with oxymatrine were CACNA1I, PADI2, and TRIM46. According to TCGA database analysis, the abundance of TRIM46 expression was higher than CACNA1I, and PADI2 in lung cancer tissues, then was selected as the final DEG for subsequent studies. We observed that oxymatrine resulted in down-expression of TRIM46 as well as induced the apoptosis of the cancer cells in a dose- and time-dependent manner. Meanwhile, we found that apoptosis induced by oxymatrine was inhibited by over-expressing TRIM46. Furthermore, our study indicated that the NF-κB signaling pathway was involved in apoptosis suppressed by TRIM46. We conclude that TRIM46 is the direct target of oxymatrine to induce anti-tumor apoptosis and may activate the downstream NF-κB signaling pathway.

Curcumenol Targeting YWHAG Inhibits the Pentose Phosphate Pathway and Enhances Antitumor Effects of Cisplatin

Objective

Cervical cancer is a common cancer in women. The drug resistance of chemotherapeutic agents has always been an urgent problem to be solved in clinics. The purpose of this study was to determine the role of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma polypeptide (YWHAG) in cervical cancer and explore the effect of Curcuma on cervical cancer and its possible mechanism.

Methods

YWHAG expression in cervical cancer was confirmed using The Cancer Genome Atlas (TCGA) database. Then, the effects of YWHAG on the proliferation and invasion of HeLa and C33A cervical cancer cells were detected by the cell counting kit-8 (CCK-8) and transwell assay. The relationship between YWHAG and the pentose phosphorylation pathway was further studied. CCK-8, Edu, and quantitative real-time polymerase chain reaction were used to confirm that Curcuma inhibited the sensitivity of YWHAG to cisplatin chemotherapy and to detect the expression of apoptosis-related proteins.

Results

YWHAG was highly expressed in cervical cancer and was associated with poor prognosis. The proliferation and invasion abilities of HeLa and C33A cells decreased after YWHAG knockout. The TCGA database of cervical cancer showed a positive correlation between YWHAG and hypoxia-inducible factor-1 subunit alpha (HIF-1α) expression. YWHAG expression increased with HIF-1α overexpression. YWHAG knockdown reduced the protein expression in the pentose phosphorylation pathway. Curcumenol inhibited YWHAG expression. Compared with cisplatin alone, curcumenol combined with cisplatin can reduce cell proliferation and invasion and reduce matrix metalloproteinase (MMP) 2 and MMP9 expression. It can also increase apoptosis, decrease B cell lymphoma 2 (Bcl-2) expression, and increase the expression of Bcl-2 antagonist X, caspase-3, and polyadenosine diphosphate-ribose polymerase.

Conclusion

YWHAG can interact with HIF-1α to affect the proliferation and invasion of cervical cancer cells. YWHAG knockout can reduce the expression of pentose phosphorylation pathway-related proteins. Curcumenol can enhance cisplatin to inhibit cancer cell proliferation, migration, and invasion and promote tumor cell apoptosis. The combination of drugs may promote the apoptosis of cervical cancer cells through the YWHAG pathway.

Therapeutic Effects of Natural Products on Cervical Cancer: Based on Inflammatory Pathways

Inflammation is a protective response of the body to an irritant. When an inflammatory response occurs, immune cells are recruited to the injury, eliminating the irritation. The excessive inflammatory response can cause harm to the organism. Inflammation has been found to contribute to cervical cancer if there is a problem with the regulation of inflammatory response. Cervical cancer is one of the most common malignant tumors globally, and the incidence tends to be younger. The harm of cervical cancer cannot be ignored. The standard treatments for cervical cancer include surgery, radiotherapy and chemotherapy. However, the prognosis for this treatment is poor, so it is urgent to find a safer and more effective treatment. Natural products are considered excellent candidates for the treatment of cervical cancer. In this review, we first describe the mechanisms by which inflammation induces cervical cancer. Subsequently, we highlight natural products that can treat cervical cancer through inflammatory pathways. We also introduce natural products for the treatment of cervical cancer in clinical trials. Finally, methods to improve the anticancer properties of natural products were added, and the development status of natural products was discussed.

Modulation of inflammation by phytochemicals to enhance efficacy and reduce toxicity of cancer chemotherapy

Treatment of cancer with chemotherapeutic drugs is associated with numerous adverse effects as well as the eventual development of resistance to chemotherapy. There is a great need for complementary therapies such as botanicals and nutritional supplements with little or no side effects that prevent resistance to chemotherapy and reduce its adverse effects. Inflammation plays a major role in the development of chemoresistance and the adverse effects of chemotherapy. Phytochemicals have well-established anti-inflammatory effects; thus, they could be used as complementary therapies along with chemotherapy to increase its efficacy and reduce its toxicity. Botanical compounds inhibit the NF-κB signaling pathway, which plays an important role in the generation of inflammation, chemotherapy resistance, and modulation of cell survival and apoptosis. Botanicals have previously been studied extensively for their cancer chemopreventive activities and are generally considered safe for human consumption. The present review focuses on the modulation of inflammation by phytochemicals and their role in increasing the efficacy and reducing the toxicity of cancer chemotherapy.

Nutrition in Gynecological Diseases: Current Perspectives

Diet and nutrition are fundamental in maintaining the general health of populations, including women's health. Health status can be affected by nutrient deficiency and vice versa. Gene-nutrient interactions are important contributors to health management and disease prevention. Nutrition can alter gene expression, as well as the susceptibility to diseases, including cancer, through several mechanisms. Gynecological diseases in general are diseases involving the female reproductive system and include benign and malignant tumors, infections, and endocrine diseases. Benign diseases such as uterine fibroids and endometriosis are common, with a negative impact on women's quality of life, while malignant tumors are among the most common cause of death in the recent years. In this comprehensive review article, a bibliographic search was performed for retrieving information about nutrients and how their deficiencies can be associated with gynecological diseases, namely polycystic ovary syndrome, infertility, uterine fibroids, endometriosis, dysmenorrhea, and infections, as well as cervical, endometrial, and ovarian cancers. Moreover, we discussed the potential beneficial impact of promising natural compounds and dietary supplements on alleviating these significant diseases.

High Risk α-HPV E6 Impairs Translesion Synthesis by Blocking POLη Induction

Simple Summary

Cervical cancers (CaCx) are caused by the expression of human papillomavirus oncogenes (HPV E6 and E7). Here, in vitro assays, computational approaches and immunohistochemical analysis of cervical biopsies show that HPV oncogenes impair translesion synthesis (TLS). This limits the pathway’s ability to prevent replication stress from causing fork collapse and DNA damage. As a result, HPV oncogenes make cells more sensitive to replication stressing agents, such as Cisplatin. Mechanistically, HPV E6 prevents replication stress from triggering the accumulation of a TLS-specific polymerase (POLη). Supplying exogenous POLη to CaCx cells rescues TLS and lowers Cisplatin toxicity.

Abstract

High risk genus α human papillomaviruses (α-HPVs) express two versatile oncogenes (α-HPV E6 and E7) that cause cervical cancer (CaCx) by degrading tumor suppressor proteins (p53 and RB). α-HPV E7 also promotes replication stress and alters DNA damage responses (DDR). The translesion synthesis pathway (TLS) mitigates DNA damage by preventing replication stress from causing replication fork collapse. Computational analysis of gene expression in CaCx transcriptomic datasets identified a frequent increased expression of TLS genes. However, the essential TLS polymerases did not follow this pattern. These data were confirmed with in vitro and ex vivo systems. Further interrogation of TLS, using POLη as a representative TLS polymerase, demonstrated that α-HPV16 E6 blocks TLS polymerase induction by degrading p53. This doomed the pathway, leading to increased replication fork collapse and sensitivity to treatments that cause replication stress (e.g., UV and Cisplatin). This sensitivity could be overcome by the addition of exogenous POLη.

Pentoxifylline Sensitizes Cisplatin-Resistant Human Cervical Cancer Cells to Cisplatin Treatment: Involvement of Mitochondrial and NF-Kappa B Pathways

Background

Cervical cancer continues to be a major public health problem worldwide, and Cisplatin is used as first-line chemotherapy for this cancer; however, malignant cells exposed to CISplatin (CIS) become insensitive to the effects of this drug. PenToXifylline (PTX) is a xanthine that sensitizes several types of tumor cells to apoptosis induced by antitumor drugs, such as Adriamycin, Carboplatin, and CIS. The effects of PTX on tumor cells have been related to the disruption of the NF-κB pathway, thus preventing the activation of cell survival mechanisms such as the expression of anti-apoptotic genes, the secretion of proinflammatory interleukins, and growth factors.

Objective

In this work, we studied the antitumor proprieties of PTX in human SiHa cervical carcinoma cells resistant to CIS.

Materials and Methods

SiHa and HeLa cervical cancer cells and their CIS-resistant derived cell lines (SiHaCIS-R and HeLaCIS-R, respectively) were used as in-vitro models. We studied the effects of PTX alone or in combination with CIS on cell viability, apoptosis, caspase-3, caspase-8, and caspase-9 activity, cleaved PARP-1, anti-apoptotic protein (Bcl-2 and Bcl-xL) levels, p65 phosphorylation, cadmium chloride (CdCl₂) sensitivity, Platinum (Pt) accumulation, and glutathione (GSH) levels, as well as on the gene expression of GSH and drug transporters (influx and efflux).

Results

PTX sensitized SiHaCIS-R cells to the effects of CIS by inducing apoptosis, caspase activation, and PARP-1 cleavage. PTX treatment also decreased p65 phosphorylation, increased Pt levels, depleted GSH, and downregulated the expression of the ATP7A, ATP7B, GSR, and MGST1 genes.

Conclusion

PTX reverses the acquired phenotype of CIS resistance close to the sensitivity of parental SiHa cells.

HP1γ Sensitizes Cervical Cancer Cells to Cisplatin through the Suppression of UBE2L3

Cisplatin is the most frequently used agent for chemotherapy against cervical cancer. However, recurrent use of cisplatin induces resistance, representing a major hurdle in the treatment of cervical cancer. Our previous study revealed that HP1γ suppresses UBE2L3, an E2 ubiquitin conjugating enzyme, thereby enhancing the stability of tumor suppressor p53 specifically in cervical cancer cells. As a follow-up study of our previous findings, here we have identified that the pharmacological substances, leptomycin B and doxorubicin, can improve the sensitivity of cervical cancer cells to cisplatin inducing HP1γ-mediated elevation of p53. Leptomycin B, which inhibits the nuclear export of HP1γ, increased cisplatin-dependent apoptosis induction by promoting the activation of p53 signaling. We also found that doxorubicin, which induces the DNA damage response, promotes HP1γ-mediated silencing of UBE2L3 and increases p53 stability. These effects resulted from the nuclear translocation and binding of HP1γ on the UBE2L3 promoter. Doxorubicin sensitized the cisplatin-resistant cervical cancer cells, enhancing their p53 levels and rate of apoptosis when administered together with cisplatin. Our findings reveal a therapeutic strategy to target a specific molecular pathway that contributes to p53 degradation for the treatment of patients with cervical cancer, particularly with cisplatin resistance.

Induction of Apoptosis and Growth-Inhibition by Thymoquinone in ACHN and GP-293 Cell Lines in Comparable with Cis-Platinum

Objective

In the current work, we investigated the cytotoxic and apoptotic effects of Thymoquinone (TQ), an active compound of Nigella sativa (N. sativa) and Cis-platinum, on normal renal epithelial (GP-293) and human renal adenocarcinoma cell lines (ACHN).

Methods

GP-293 and ACHN cell lines were cultured in Dulbecco’s modified Eagle’s medium (DMEM) with 10% Fetal bovine serum (FBS) and 1% penicillin plus streptomycin antibiotic. The MTT assay was used for cellular viability assessment. Viability of cells was observed using inverted light microscope 24, 48 and 72 h after exposure of the cells to various concentrations of TQ (1, 2.5, 5, 10, 50 and 100 μg/ml) and Cis-platinum (0.5, 1, 1.5, 2, 3, 6 and 12.5 μg/ml). Moreover, apoptosis was analyzed with a flow-cytometry method. The untreated cells were considered as control group.

Results

Morphological changes such as reduced cell number and increased intercellular distance and reduced cell viability in ACHN and GP-293cell lines were observed in both TQ and Cis-platinum groups; however, Cis-platinum had greater effect on ACHN cell line than GP-293 cell line. In addition, GP-293 cell line was more sensitive to TQ compared to ACHN cell line. Furthermore, TQ and Cis-platinum had apoptotic effects on both ACHN and GP-293 cell lines.

Conclusion

Our findings demonstrated that TQ and Cis-platinum had cytotoxic and apoptotic effects on both cell lines, However, GP-293 cell line was more sensitive to TQ. Additionally, Cis-platinum was more effective on ACHN cell line than on GP-293 cell line.

The anti-tumor function of the IKK inhibitor PS1145 and high levels of p65 and KLF4 are associated with the drug resistance in nasopharyngeal carcinoma cells

We and others have previously shown that the canonical nuclear factor kappa-B (NF-κB) pathway is essential to nasopharyngeal carcinoma (NPC) tumor development and angiogenesis, suggesting that the NF-κB pathway, including its upstream modulators and downstream effectors, are potential therapeutic targets for NPC. The inhibitor of upstream IκB kinase (IKK), PS1145, is a small molecule which can specifically inhibit the IκB phosphorylation and degradation and the subsequent nuclear translocation of NF-κB. The present study aims to determine the anti-tumor activity of PS1145 on NPC. Our results showed that PS1145 significantly inhibited the growth of tumorigenic NPC cell lines, but not in the normal nasopharyngeal epithelial cell line. Results in the in vivo study showed that low concentration of PS1145 (3 mg/kg) could significantly suppress the subcutaneous tumor formation in the nude mice bearing NPC xenografts. Apparent adverse effects were not observed in the animal study. Drug resistance against PS1145 seems to be associated with the increased levels of active NF-kB p65 and change of expression levels of kruppel-like factor 4. As can be seen, PS1145 appears to be a safe agent for animal experiments and its effects are tumor-specific, and the proteins associated with the drug resistance of PS1145 are implied.

Identification of a novel S6K1 inhibitor, rosmarinic acid methyl ester, for treating cisplatin-resistant cervical cancer

Background

The mTOR/S6K1 signaling pathway is often activated in cervical cancer, and thus considered a molecular target for cervical cancer therapies. Inhibiting mTOR is cytotoxic to cervical cancer cells and creates a synergistic anti-tumor effect with conventional chemotherapy agents. In this study, we identified a novel S6K1 inhibitor, rosmarinic acid methyl ester (RAME) for the use of therapeutic agent against cervical cancer.

Methods

Combined structure- and ligand-based virtual screening was employed to identify novel S6K1 inhibitors among the in house natural product library. In vitro kinase assay and immunoblot assay was used to examine the effects of RAME on S6K1 signaling pathway. Lipidation of LC3 and mRNA levels of ATG genes were observed to investigate RAME-mediated autophagy. PARP cleavage, mRNA levels of apoptotic genes, and cell survival was measured to examine RAME-mediated apoptosis.

Results

RAME was identified as a novel S6K1 inhibitor through the virtual screening. RAME, not rosmarinic acid, effectively reduced mTOR-mediated S6K1 activation and the kinase activity of S6K1 by blocking the interaction between S6K1 and mTOR. Treatment of cervical cancer cells with RAME promoted autophagy and apoptosis, decreasing cell survival rate. Furthermore, we observed that combination treatment with RAME and cisplatin greatly enhanced the anti-tumor effect in cisplatin-resistant cervical cancer cells, which was likely due to mTOR/S6K1 inhibition-mediated autophagy and apoptosis.

Conclusions

Our findings suggest that inhibition of S6K1 by RAME can induce autophagy and apoptosis in cervical cancer cells, and provide a potential option for cervical cancer treatment, particularly when combined with cisplatin.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5997-2) contains supplementary material, which is available to authorized users.

PARP-1 inhibitor modulate β-catenin signaling to enhance cisplatin sensitivity in cancer cervix

Cisplatin is a keystone for treatment of both recurring and locally advanced cervical cancer. However toxic side effects and acquired resistance limits its efficacy. Enhanced DNA repair is one of the mechanisms through which cancer cells acquire cisplatin resistance. Inhibitors of PARP, which is a DNA damage repair enzyme, have been approved for use in BRCA mutated cancers like breast and ovary cancer. However little is known about the therapeutic efficacy of PARP inhibitors in cervical cancer, either as a single agent or in combination with cisplatin. We hypothesized that PARP-1 inhibition might improve the sensitivity of cervical cancer cells to cisplatin by diminishing DNA repair. To ascertain this, we determined effect of PARP-1 inhibition on cisplatin cytotoxicity in HeLa and SiHa cell lines. Combination of cisplatin with PJ34, a phenanthridinone-derived PARP-1 inhibitor, augmented cisplatin toxicity in vitro by decreasing cell proliferation, enhancing cell cycle block and cell death, and decreasing invasion and metastasis, when compared with either of the single agent alone. We further show that PARP-1 inhibition inhibited β-catenin signaling and its downstream components such as c-Myc, cyclin D1 and MMPs indicating a possible link between single strand base damage repair and WNT signaling. In conclusion, PARP-1 inhibition might augment cisplatin cytotoxicity in cervical cancer cells by modulating β-catenin signaling pathway. Combining PARP-1 inhibitors with cisplatin might be a promising approach to overcome cisplatin resistance and to achieve a better therapeutic effect.

Oxidative stress: therapeutic approaches for cervical cancer treatment

Oxidative stress results from an imbalance between the generation and elimination of oxidant species. This condition may result in DNA, RNA and protein damage, leading to the accumulation of genetic alterations that can favor malignant transformation. Persistent infection with high-risk human papillomavirus types is associated with inflammatory responses and reactive oxygen species production. In this context, oxidative stress, chronic inflammation and high-risk human papillomavirus can act in a synergistic manner. To counteract the harmful effects of oxidant species, protective molecules, known as antioxidant defenses, are produced by cells to maintain redox homeostasis. In recent years, the use of natural antioxidants as therapeutic strategies for cancer treatment has attracted the attention of the scientific community. This review discusses specific molecules and mechanisms that can act against or together with oxidative stress, presenting alternatives for cervical cancer prevention and treatment.

Hydroxide assisted synthesis of monodisperse and biocompatible gold nanoparticles with dextran

A simple and rapid approach to synthesize monodisperse and biocompatible gold nanoparticles (AuNPs) employing dextran as a reducing and stabilizing agents at different reaction conditions was described. The obtained dextran-gold nanoparticles (Dex-AuNPs) were characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, Nuclear magnetic resonance (NMR) spectroscopy, Fourier transformer infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The TEM examinations showed the resultant particles were 4-50 nm in size, monodispersity and uniform particle size distribution. Moreover, the size of the nanoparticles can be controlled by varying the concentration of the reactants. UV-Vis spectra showed that the characteristic localized surface plasmon resonance (LSPR) band of AuNPs was at about 525 nm. NMR spectroscopy and FTIR spectroscopic analysis suggested the detailed structural information of dextran before and after synthesis of AuNPs. XRD and selected area electron diffraction (SAED) pattern analysis demonstrated that the colloidal nanoparticles had a well crystallized structure. The experimental analyses revealed that NaOH played an important role in the synthesis of Dex-AuNPs. And the possible formation mechanism of the fabrication of these Dex-AuNPs was also proposed. MTT assay was utilized to evaluate the cytotoxicity of the synthesized Dex-AuNPs on HeLa cells and SiHa cells. These results suggested that the prepared Dex-AuNPs complexes had excellent biocompatibility and acted as a candidate for further biomedical application.

Influence of TS (rs34743033) and RUNX1 (rs2014300) gene polymorphisms on survival outcomes of fluorouracil-based chemotherapy in Chinese advanced gastric cancer patients

Background

This study aimed to explore the clinical correlation of single-nucleotide polymorphisms of thymidylate synthase (TS) and runt-related transcription factor 1 (RUNX1) in patients with postoperative stage II and III gastric cancer (GC).

Patients and methods

Samples were obtained from 661 patients with postoperative stage II and III GC. TS (rs34743033) and RUNX1 (rs2014300) were genotyped in 261 patients who received postoperative basic platinum and fluorouracil chemotherapy regimens and 400 patients who did not accept chemotherapy.

Results

TS (rs34743033) variant genotypes significantly prolonged the median overall survival (OS) time compared to the patients who only received adjuvant chemotherapy (HR 1.604, 95% CI 1.068–2.410, p=0.021). Moreover, 3R/3R variant genotypes were demonstrated to have a positive effect on the OS of patients who received chemotherapy based on cisplatin (HR 1.754, 95% CI 1.041–2.954, p=0.031) compared to oxaliplatin. A stratification analysis indicated that 2R/3R and 2R/2R variant genotypes were associated with inferior survival in GC patients with intestinal-type tumors, tumor less than 5 cm in size, and poorly differentiated tumors (p<0.05). However, RUNX1 (rs2014300) AA genotypes markedly increased the risk of death in GC patients compared with the GG/GA genotypes (p=0.007), but no significant difference was observed between chemotherapy based on platinum. The stratification analysis showed that the GA/AA genotype was significantly associated with inferior survival in well to moderately differentiated tumors (HR 2.001, 95% CI 1.082–3.703, p=0.023).

Conclusion

These preliminary results indicated that the two polymorphisms had a significant effect on postoperative adjuvant chemotherapy. TS (rs34743033) and RUNX1 (rs2014300) may be used as biomarkers to predict prognosis and select chemotherapy regimens in GC patients.

Cytoplasmic RAP1 mediates cisplatin resistance of non-small cell lung cancer

Cytotoxic chemotherapy agents (e.g., cisplatin) are the first-line drugs to treat non-small cell lung cancer (NSCLC) but NSCLC develops resistance to the agent, limiting therapeutic efficacy. Despite many approaches to identifying the underlying mechanism for cisplatin resistance, there remains a lack of effective targets in the population that resist cisplatin treatment. In this study, we sought to investigate the role of cytoplasmic RAP1, a previously identified positive regulator of NF-κB signaling, in the development of cisplatin resistance in NSCLC cells. We found that the expression of cytoplasmic RAP1 was significantly higher in high-grade NSCLC tissues than in low-grade NSCLC; compared with a normal pulmonary epithelial cell line, the A549 NSCLC cells exhibited more cytoplasmic RAP1 expression as well as increased NF-κB activity; cisplatin treatment resulted in a further increase of cytoplasmic RAP1 in A549 cells; overexpression of RAP1 desensitized the A549 cells to cisplatin, and conversely, RAP1 depletion in the NSCLC cells reduced their proliferation and increased their sensitivity to cisplatin, indicating that RAP1 is required for cell growth and has a key mediating role in the development of cisplatin resistance in NSCLC cells. The RAP1-mediated cisplatin resistance was associated with the activation of NF-κB signaling and the upregulation of the antiapoptosis factor BCL-2. Intriguingly, in the small portion of RAP1-depleted cells that survived cisplatin treatment, no induction of NF-κB activity and BCL-2 expression was observed. Furthermore, in established cisplatin-resistant A549 cells, RAP1 depletion caused BCL2 depletion, caspase activation and dramatic lethality to the cells. Hence, our results demonstrate that the cytoplasmic RAP1–NF-κB–BCL2 axis represents a key pathway to cisplatin resistance in NSCLC cells, identifying RAP1 as a marker and a potential therapeutic target for cisplatin resistance of NSCLC.

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.

Ameliorative effect of selenium in cisplatin-induced testicular damage in rats

In this study, we investigated the protective effect of selenium (Se) on cisplatin (Cis) induced testicular damage using histopathological, immunohistochemical and biochemical approaches. Twenty-one male Wistar rats were equally divided into three groups of seven rats each: control (C), Cis, and Cis+Se. Cis and Cis+Se group rats received Cis at a dose of 12mg/kg b.w./day, intraperitoneally for 3 consecutive days. Cis+Se group rats received selenium via oral gavage 3mg/kg/day (twice-a day as 1.5mg/kg) until 11th consecutive days starting at 5 days before cisplatin injection. C group received only 0.9% NaCl intraperitoneally and orally at same time and at equal volume. After the treatment, the histopathological, immunohistochemical and biochemical examinations were performed. In seminiferous tubules of Cis treated rats were observed the most consistent findings characterized with vacuolization, desquamation, disorganization, and also was a considerable reduction in elongated spermatids, however the Cis+Se group exhibited improved histopathologic changes. In the immunohistochemical examinations, caspase-3 immunopositive cells displayed higher in the Cis group according to C and Cis+Se groups. Bcl-2 and NF-κB staining revealed a moderate number in the C group and significantly fewer in the Cis group compared to the Cis+Se groups. Additionally, MDA levels were also significantly increased in the Cis group in comparison to Control group, but pretreatment with selenium prevented elevation of MDA levels significantly in Cis+Se group rats. This study indicates that Cis-treatment induced testicular apoptosis and lipid peroxidation, and combined treatment with selenium prevented severity of the toxicity in rats.

Sensitization of ovarian cancer cells to cisplatin by gold nanoparticles

Recently we reported that gold nanoparticles (AuNPs) inhibit ovarian tumor growth and metastasis in mice by reversing epithelial-mesenchymal transition (EMT). Since EMT is known to confer drug resistance to cancer cells, we wanted to investigate whether anti-EMT property of AuNP could be utilized to sensitize ovarian cancer cells to cisplatin. Herein, we report that AuNPs prevent cisplatin-induced acquired chemoresistance and stemness in ovarian cancer cells and sensitize them to cisplatin. AuNPs inhibit cisplatin induced EMT, decrease the side population cells and key stem cell markers such as ALDH1, CD44, CD133, Sox2, MDR1 and ABCG2 in ovarian cancer cells. Mechanistically, AuNPs prevent cisplatin-induced activation of Akt and NF-κB signaling axis in ovarian cancer cells that are critical for EMT, stem cell maintenance and drug resistance. In vivo, AuNPs sensitize orthotopically implanted ovarian tumor to a low dose of cisplatin and significantly inhibit tumor growth via facilitated delivery of both AuNP and cisplatin. These findings suggest that by depleting stem cell pools and inhibiting key molecular pathways gold nanoparticles sensitize ovarian cancer cells to cisplatin and may be used in combination to inhibit tumor growth and metastasis in ovarian cancer.

PLGA-encapsulated tea polyphenols enhance the chemotherapeutic efficacy of cisplatin against human cancer cells and mice bearing Ehrlich ascites carcinoma

The clinical success of the applicability of tea polyphenols awaits efficient systemic delivery and bioavailability. Herein, following the concept of nanochemoprevention, which uses nanotechnology for enhancing the efficacy of chemotherapeutic drugs, we employed tea polyphenols, namely theaflavin (TF) and epigallocatechin-3-gallate (EGCG) encapsulated in a biodegradable nanoparticulate formulation based on poly(lactide-co-glycolide) (PLGA) with approximately 26% and 18% encapsulation efficiency, respectively. It was observed that TF/EGCG encapsulated PLGA nanoparticles (NPs) offered an up to ~7-fold dose advantage when compared with bulk TF/EGCG in terms of exerting its antiproliferative effects and also enhanced the anticancer potential of cisplatin (CDDP) in A549 (lung carcinoma), HeLa (cervical carcinoma), and THP-1 (acute monocytic leukemia) cells. Cell cycle analysis revealed that TF/EGCG-NPs were more efficient than bulk TF/EGCG in sensitizing A549 cells to CDDP-induced apoptosis, with a dose advantage of up to 20-fold. Further, TF/EGCG-NPs, alone or in combination with CDDP, were more effective in inhibiting NF-κB activation and in suppressing the expression of cyclin D1, matrix metalloproteinase-9, and vascular endothelial growth factor, involved in cell proliferation, metastasis, and angiogenesis, respectively. EGCG and TF-NPs were also found to be more effective than bulk TF/EGCG in inducing the cleavage of caspase-3 and caspase-9 and Bax/Bcl2 ratio in favor of apoptosis. Further, in vivo evaluation of these NPs in combination with CDDP showed an increase in life span (P<0.05) in mice bearing Ehrlich's ascites carcinoma cells, with apparent regression of tumor volume in comparison with mice treated with bulk doses with CDDP. These results indicate that EGCG and TF-NPs have superior cancer chemosensitization activity when compared with bulk TF/EGCG.

Alpha-catulin contributes to drug-resistance of melanoma by activating NF-κB and AP-1

Melanoma is the most dangerous type of skin cancer accounting for 48,000 deaths worldwide each year and an average survival rate of about 6-10 months with conventional treatment. Tumor metastasis and chemoresistance of melanoma cells are reported as the main reasons for the insufficiency of currently available treatments for late stage melanoma. The cytoskeletal linker protein α-catulin (CTNNAL1) has been shown to be important in inflammation, apoptosis and cytoskeletal reorganization. Recently, we found an elevated expression of α-catulin in melanoma cells. Ectopic expression of α-catulin promoted melanoma progression and occurred concomitantly with the downregulation of E-cadherin and the upregulation of mesenchymal genes such as N-cadherin, Snail/Slug and the matrix metalloproteinases 2 and 9. In the current study we showed that α-catulin knockdown reduced NF-κB and AP-1 activity in malignant melanoma cells. Further, downregulation of α-catulin diminished ERK phosphorylation in malignant melanoma cells and sensitized them to treatment with chemotherapeutic drugs. In particular, cisplatin treatment led to decreased ERK-, JNK- and c-Jun phosphorylation in α-catulin knockdown melanoma cells, which was accompanied by enhanced apoptosis compared to control cells. Altogether, these results suggest that targeted inhibition of α-catulin may be used as a viable therapeutic strategy to chemosensitize melanoma cells to cisplatin by down-regulation of NF-κB and MAPK pathways.

Cytotoxic effects of pyrrolidine dithiocarbamate in small-cell lung cancer cells, alone and in combination with cisplatin

The cytocidal effect of pyrrolidine dithiocarbamate (PDTC) was investigated by focusing on cell viability, cell cycle arrest and apoptosis induction in small-cell lung cancer (SCLC) cell lines (NCI-H196 and NCI-H889). PDTC exhibited a much stronger dose-dependent cytotoxic activity against NCI-H196 compared to NCI-H889, while no such activity was observed in normal human embryonal lung fibroblast MRC-5 cells. Cell cycle arrest in S phase paralleled with suppression of c-myc expression without accompanying DNA fragmentation was observed in NCI-H196 cells. A transient increase in the intracellular ROS accompanied with an alteration of expression of oxidative stress-related genes was also confirmed in NCI-H196 cells. Furthermore, the addition of N-acetyl-l-cysteine (NAC), a free radical scavenger, not only abolished PDTC-trigger alterations of expression of these oxidative-related genes, but also almost completely abrogated PDTC-induced reduction in cell viability and morphological changes associated with cell damage. These results thus suggest that PDTC-induced cytotoxicity is attributed to its pro-oxidant activity. PDTC-induced cytotoxicity was further enhanced by CuCl2, however, abolished by bathocuproine disulfonate (BCPS), a non-permeable copper-specific chelator, supporting the plausibility that accumulation of intracellular Cu plays an important role in the cytotoxicity. Importantly, we demonstrated for the first time that PDTC downregulated the expression of ATP7A, known to be responsible for Cu efflux, but did not affect the expression of CTR1, known as a copper uptake transporter. Intriguingly, combination of much lower dose of cisplatin (5 µM) and non-toxic dose of PDTC (0.1 µM) synergistically induced a significant cytotoxicity in NCI-H196 cells. Given that ATP7A plays a critical role in the resistance of platinum-drug (such as cisplatin) representing a first-line treatment for SCLC, PDTC could be a promising candidate of adjunct therapeutic reagent for the patients requiring treatment with platinum-based regimens.

Synergistic effect of pyrrolidine dithiocarbamate and cisplatin in human cervical carcinoma

We aimed to delineate how pyrrolidine dithiocarbamate (PDTC) affects nuclear factor κB (NF-κB) and to determine its antitumor activity alone and in combination with cisplatin in human cervical cancer SiHa cells. The SiHa cells were treated with various concentrations of PDTC and/or cisplatin at various time intervals. Cell proliferation and apoptosis were determined using a water-soluble tetrazolium salt 8 assay and flow cytometry. Electrophoretic mobility shift assay was used to assess NF-κB activity. Pyrrolidine dithiocarbamate (2.5-100 µmol/L) was found to inhibit the growth of SiHa cell lines. Cisplatin (0.01-20.0 μg/mL) and PDTC (2.5-20.0 µmol/L) combined demonstrated additive inhibitive effects on cell growth and increased the level of apoptosis. In addition, PDTC blocked cisplatin-induced activation of NF-κB, leading to enhanced apoptosis and increased chemosensitivity to cisplatin. Taken together, PDTC has significant potential as a chemotherapy agent, alone or in combination with cisplatin.

Different affinity of nuclear factor-kappa B proteins to DNA modified by antitumor cisplatin and its clinically ineffective trans isomer

Nuclear factor-kappa B (NF-кB) comprises a family of protein transcription factors that have a regulatory function in numerous cellular processes and are implicated in the cancer cell response to antineoplastic drugs, including cisplatin. We characterized the effects of DNA adducts of cisplatin and ineffective transplatin on the affinity of NF-кB proteins to their consensus DNA sequence (кB site). Although the кB site-NF-κB protein interaction was significantly perturbed by DNA adducts of cisplatin, transplatin adducts were markedly less effective both in cell-free media and in cellulo using a decoy strategy derivatized-approach. Moreover, NF-κB inhibitor JSH-23 [4-methyl-N¹-(3-phenylpropyl)benzene-1,2-diamine] augmented cisplatin cytotoxicity in ovarian cancer cells and the data showed strong synergy with JSH-23 for cisplatin. The distinctive structural features of DNA adducts of the two platinum complexes suggest a unique role for conformational distortions induced in DNA by the adducts of cisplatin with respect to inhibition of the binding of NF-кB to the platinated кB sites. Because thousands of κB sites are present in the DNA, the mechanisms underlying the antitumor efficiency of cisplatin in some tumor cells may involve downstream processes after inhibition of the binding of NF-κB to κB site(s) by DNA adducts of cisplatin, including enhanced programmed cell death in response to drug treatment.

Inhibitory impacts of chemically modified tetracycline-3 and underlying mechanism in human cervical cancer cells

Chemically modified tetracyclines (CMTs) have been rationally designed from tetracyclines. The CMTs that show the antimicrobial properties are eliminated, whereas matrix metalloproteinase inhibitory properties are retained. Interestingly, CMT-3 (COL-3, by eliminating the dimethylamino, methyl, and hydroxyl functionalities on the basic tetracycline structure), one of the CMTs, has shown strong anticancer activity. In this study, we found that CMT-3 showed dose-dependent and time-dependent cytotoxicity in HeLa and Siha cells, two human cervical cancer cell lines. HeLa cells were more sensitive to CMT-3 compared with Siha cells. The antiproliferation potential of CMT-3 was associated with the mitochondrial apoptosis pathway, increasing reactive oxygen species level, and proapoptosis protein (e.g. caspase-3) expression, but decreasing antiapoptosis protein expression (e.g. Bcl-2). N-acetylcysteine (a reactive oxygen species inhibitor) and Z-LEHD-FMK significantly reduced or blocked the apoptosis event resulting from cytotoxic effect of CMT-3. CMT-3 also induced G0/G1 phase arrest with the reduction of cell cycle regulatory protein cyclin E and the translocation of NF-κB from the cytoplasm to the nucleus. Our findings provide the important foundation for further investigation of the underlying mechanism for the anticancer activity of CMT-3 and the potential application of CMT-3 as a new therapeutic candidate for clinical cervical cancer therapy.

Moringa Oleifera aqueous leaf extract down-regulates nuclear factor-kappaB and increases cytotoxic effect of chemotherapy in pancreatic cancer cells

BACKGROUND

Fewer than 6% patients with adenocarcinoma of the pancreas live up to five years after diagnosis. Chemotherapy is currently the standard treatment, however, these tumors often develop drug resistance over time. Agents for increasing the cytotoxic effects of chemotherapy or reducing the cancer cells' chemo-resistance to the drugs are required to improve treatment outcome. Nuclear factor kappa B (NF-kB), a pro-inflammatory transcription factor, reportedly plays a significant role in the resistance of pancreatic cancer cells to apoptosis-based chemotherapy. This study investigated the effect of aqueous Moringa Oleifera leaf extract on cultured human pancreatic cancer cells - Panc-1, p34, and COLO 357, and whether it can potentiates the effect of cisplatin chemotherapy on these cells.

METHODS

The effect of Moringa Oleifera leaf extract alone and in combination with cisplatin on the survival of cultured human pancreatic cancer cells was evaluated by XTT-based colorimetric assay. The distribution of Panc-1 cells in the cell cycle following treatment with Moringa leaf extract was evaluated by flow cytometry, and evaluations of protein levels were via immunoblotting. Data of cell survival following combined treatments were analyzed with Calcusyn software.

RESULTS

Moringa Oleifera leaf extract inhibited the growth of all pancreatic cell lines tested. This effect was significant in all cells following exposure to ≥0.75 mg/ml of the extract. Exposure of Panc-1 cells to Moringa leaf extract induced an elevation in the sub-G1 cell population of the cell-cycle, and reduced the expression of p65, p-IkBα and IkBα proteins in crude cell extracts. Lastly, Moringa Oleifera leaf extract synergistically enhanced the cytotoxic effect of cisplatin on Panc-1 cells.

CONCLUSION

Moringa Oleifera leaf extract inhibits the growth of pancreatic cancer cells, the cells NF-κB signaling pathway, and increases the efficacy of chemotherapy in human pancreatic cancer cells.

Disrupting protein NEDDylation with MLN4924 is a novel strategy to target cisplatin resistance in ovarian cancer

PURPOSE

Ovarian cancer has the highest mortality rate of all female reproductive malignancies. Drug resistance is a major cause of treatment failure and novel therapeutic strategies are urgently needed. MLN4924 is a NEDDylation inhibitor currently under investigation in multiple phase I studies. We investigated its anticancer activity in cisplatin-sensitive and -resistant ovarian cancer models.

EXPERIMENTAL DESIGN

Cellular sensitivity to MLN4924/cisplatin was determined by measuring viability, clonogenic survival, and apoptosis. The effects of drug treatment on global protein expression, DNA damage, and reactive oxygen species generation were determined. RNA interference established natural born killer/bcl-2-interacting killer (NBK/BIK) as a regulator of therapeutic sensitivity. The in vivo effects of MLN4924/cisplatin on tumor burden and key pharmacodynamics were assessed in cisplatin-sensitive and -resistant xenograft models.

RESULTS

MLN4924 possessed significant activity against both cisplatin-sensitive and -resistant ovarian cancer cells and provoked the stabilization of key NEDD8 substrates and regulators of cellular redox status. Notably, MLN4924 significantly augmented the activity of cisplatin against cisplatin-resistant cells, suggesting that aberrant NEDDylation may contribute to drug resistance. MLN4924 and cisplatin cooperated to induce DNA damage, oxidative stress, and increased expression of the BH3-only protein NBK/BIK. Targeted NBK/BIK knockdown diminished the proapoptotic effects of the MLN4924/cisplatin combination. Administration of MLN4924 to mice bearing ovarian tumor xenografts significantly increased the efficacy of cisplatin against both cisplatin-sensitive and -resistant tumors.

CONCLUSIONS

Our collective data provide a rationale for the clinical investigation of NEDD8-activating enzyme (NAE) inhibition as a novel strategy to augment cisplatin efficacy in patients with ovarian cancer and other malignancies.

Nuclear factor-kappa B and interleukin-6 related docetaxel resistance in castration-resistant prostate cancer

BACKGROUND

Previous work showed that the NF-κB survival pathway is activated by docetaxel (D) and contributes to D resistance in prostate cancer. In this study we aimed to investigate the dynamics of the relationship between NF-κB and IL-6 in the shift from D-naive castration-resistant prostate cancer (CRPC) to D-resistance in patients and cell lines.

METHODS

CRPC tumor samples were tested for NF-κB/p65 and IL-6 by immunohistochemistry. CRPC patients treated with D were also tested for serum IL-6 (ELISA). Two D-resistant cell lines, PC-3R and DU-145R, derived from the CRPC cells PC-3 and DU-145, respectively, were tested for NF-κB activation (EMSA), NF-κB-related genes expression (RT-PCR), NF-κB inhibition (p65 siRNA) and IL-6 and IL-8 soluble levels (ELISA).

RESULTS

In CRPC patients treated with D (n = 72), pre-treatment IL-6 level correlated with nuclear NF-κB/p65 tumor staining and response to D, and was an independent prognostic factor for overall survival. However, IL-6 level changes under treatment did not correlate with clinical outcome. In PC-3 and DU-145 parental CRPC cells, as well as in D-resistant counterparts, D treatment induced NF-κB activation. In fact, NF-κB inhibition was sufficient to re-sensitize DU-145R cells to D. Despite enhanced NF-κB activity, IL-6 secretion in D-resistant cell lines was reduced and not induced by D treatment. The same occurred with IL-8 cytokine.

CONCLUSIONS

These preclinical and clinical results support a role of NF-κB and IL-6 in the resistance to D in CRPC, and support the investigation of targeted therapies to enhance the antitumor activity of D in this patient population.

RETRACTED: Tea polyphenols enhance cisplatin chemosensitivity in cervical cancer cells via induction of apoptosis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Multiple figures in this article appear to be falsified/fabricated. Figure 2A and C. The representative dot plots from the EGCG (15ug/ml)+CDDP (10ug/ml) and TF (15ug/ml) groups appear to be duplicated. Figures 3, 4 and 6. Multiple Western blot bands appear to be rotated and reused throughout Figure 3 (A and B); 4 (A and B) and 6 (A, B, C). In particular, the Cytochrome-c blot in Figure 3B is duplicated and flipped in Figure 6B as p-NFKB. The p53 blot in Figure 3B is duplicated in Figure 6C as p-NFKB. The B-actin blot in Figure 3B is shown as an unmarked control lane (flipped in Figure 6B. The p53 band in Figure 3C is very similar to the Caspase 9 blot in Figure 4B and is cropped and duplicated in Figure 6A as p-NFKB by cisplatin in SiHa cells. The Caspase 3 blot in Figure 4A is rotated and flipped and appears in Figure 6B as p-IKBa.

Alterations of microRNA expression patterns in human cervical carcinoma cells (Ca Ski) toward 1'S-1'-acetoxychavicol acetate and cisplatin

The aims of this study were to investigate the combined effects of a natural compound 1'S-1'-acetoxychavicol acetate (ACA) with cisplatin (CDDP) on HPV-positive human cervical carcinoma cell lines (Ca Ski-low cisplatin sensitivity and HeLa-high cisplatin sensitivity), and to identify microRNAs (miRNAs) modulated in response toward ACA and/or CDDP. It was revealed that both ACA and CDDP induced dose- and time-dependent cytotoxicity when used as a stand-alone agent, while synergistic effects were observed when used in combination with a combination index (CI) value of 0.74 ± 0.01 and 0.85 ± 0.01 in Ca Ski and HeLa cells, respectively. A total of 25 miRNAs were found to be significantly differentially expressed in response to ACA and/or CDDP. These include hsa-miR-138, hsa-miR-210, and hsa-miR-744 with predicted gene targets involved in signaling pathways regulating apoptosis and cell cycle progression. In conclusion, ACA acts as a chemosensitizer which synergistically potentiates the cytotoxic effect of CDDP in cervical cancer cells. The altered miRNA expression upon administration of ACA and/or CDDP suggests that miRNAs play an important role in anticancer drug responses, which can be manipulated for therapeutic purposes.

GAP161 targets and downregulates G3BP to suppress cell growth and potentiate cisplaitin-mediated cytotoxicity to colon carcinoma HCT116 cells

Ras-GTPase-activating protein SH3 domain-binding proteins (G3BP) are overexpressed in various human tumors and participate in several signaling pathways involved in growth, differentiation and apoptosis. G3BP interact with RasGAP (Ras-GTPase activating protein) only in growing cells and depend on Ras activation, and participate in the Ras signal pathway. Therefore, the blockage and downregulation of G3BP may be a new strategy for cancer therapy. In this report, we demonstrate that a novel peptide GAP161 blocked the functions of G3BP and markedly suppressed HCT116 cell growth through the induction of apoptosis. The peptide bound with G3BP, which interfered with the interaction of G3BP1 with RasGAP and further suppressed Ras signaling pathways. GAP161 downregulated G3BP1 and G3BP2 proteins. Similarly, the knockdown of G3BP substantially decreased the proliferation of HCT116 cells and inhibited Ras signal pathways. Furthermore, the downregulation of G3BP could enhance cisplatin-induced apoptosis and growth inhibition of HCT116 cells. We also found that GAP161 suppressed the growth of BALB/c mice bearing colon CT26 tumors and nude mice bearing HCT116 xenografts. These results suggest that downregulation of G3BP might be useful in cancer therapy and that GAP161 is a promising new therapeutic agent for cancers.

Inhibition of specific NF-κB activity contributes to the tumor suppressor function of 14-3-3σ in breast cancer

14-3-3σ is frequently lost in human breast cancers by genetic deletion or promoter methylation. We have now investigated the involvement of 14-3-3σ in the termination of NF-κB signal in mammary cells and its putative role in cancer relapse and metastasis. Our results show that 14-3-3σ regulates nuclear export of p65-NF-κB following chronic TNFα stimulation. Restoration of 14-3-3σ in breast cancer cells reduces migration capacity and metastatic abilities in vivo. By microarray analysis, we have identified a genetic signature that responds to TNFα in a 14-3-3σ-dependent manner and significantly associates with different breast and other types of cancer. By interrogating public databases, we have found that over-expression of this signature correlates with poor relapse-free survival in breast cancer patients. Finally, screening of 96 human breast tumors showed that NF-κB activation strictly correlates with the absence of 14-3-3σ and it is significantly associated with worse prognosis in the multivariate analysis. Our findings identify a genetic signature that is important for breast cancer prognosis and for future personalized treatments based on NF-κB targeting.

Human papillomavirus type 16 E6 and E 7 proteins alter NF-kB in cultured cervical epithelial cells and inhibition of NF-kB promotes cell growth and immortalization

The NF-kB family of transcription factors regulates important biological functions including cell growth, survival and the immune response. We found that Human Papillomavirus type 16 (HPV-16) E7 and E6/E7 proteins inhibited basal and TNF-alpha-inducible NF-kB activity in human epithelial cells cultured from the cervical transformation zone, the anatomic region where most cervical cancers develop. In contrast, HPV-16 E6 regulated NF-kB in a cell type- and cell growth-dependent manner. NF-kB influenced immortalization of cervical cells by HPV16. Inhibition of NF-kB by an IkB alpha repressor mutant increased colony formation and immortalization by HPV-16. In contrast, activation of NF-kB by constitutive expression of p65 inhibited proliferation and immortalization. Our results suggest that inhibition of NF-kB by HPV-16 E6/E7 contributes to immortalization of cells from the cervical transformation zone.

Characterisation and manipulation of docetaxel resistant prostate cancer cell lines

Background

There is no effective treatment strategy for advanced castration-resistant prostate cancer. Although Docetaxel (Taxotere^®) represents the most active chemotherapeutic agent it only gives a modest survival advantage with most patients eventually progressing because of inherent or acquired drug resistance. The aims of this study were to further investigate the mechanisms of resistance to Docetaxel. Three Docetaxel resistant sub-lines were generated and confirmed to be resistant to the apoptotic and anti-proliferative effects of increasing concentrations of Docetaxel.

Results

The resistant DU-145 R and 22RV1 R had expression of P-glycoprotein and its inhibition with Elacridar partially and totally reversed the resistant phenotype in the two cell lines respectively, which was not seen in the PC-3 resistant sublines. Resistance was also not mediated in the PC-3 cells by cellular senescence or autophagy but multiple changes in pro- and anti-apoptotic genes and proteins were demonstrated. Even though there were lower basal levels of NF-κB activity in the PC-3 D12 cells compared to the Parental PC-3, docetaxel induced higher NF-κB activity and IκB phosphorylation at 3 and 6 hours with only minor changes in the DU-145 cells. Inhibition of NF-κB with the BAY 11-7082 inhibitor reversed the resistance to Docetaxel.

Conclusion

This study confirms that multiple mechanisms contribute to Docetaxel resistance and the central transcription factor NF-κB plays an immensely important role in determining docetaxel-resistance which may represent an appropriate therapeutic target.

Direct inhibition of TNF-α promoter activity by Fanconi anemia protein FANCD2

Fanconi anemia (FA), an inherited disease, is associated with progressive bone marrow failure, predisposition to cancer, and genomic instability. Genes corresponding to 15 identified FA complementation groups have been cloned, and each gene product functions in the response to DNA damage induced by cross-linking agents and/or in protection against genome instability. Interestingly, overproduction of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and aberrant activation of NF-κB-dependent transcriptional activity have been observed in FA cells. Here we demonstrated that FANCD2 protein inhibits NF-κB activity in its monoubiquitination-dependent manner. Furthermore, we detected a specific association between FANCD2 and an NF-κB consensus element in the TNF-α promoter by electrophoretic mobility shift assays (EMSA) and chromatin immunoprecipitation (ChIP) assay. Therefore, we propose FANCD2 deficiency promotes transcriptional activity of the TNF-α promoter and induces overproduction of TNF-which then sustains prolonged inflammatory responses. These results also suggest that artificial modulation of TNFα production could be a promising therapeutic approach to FA.

Cisplatin increases B-cell-lymphoma-2 expression via activation of protein kinase C and Akt2 in endometrial cancer cells

Human carcinomas often show resistance to cisplatin and Bcl-2 is associated with resistance to cisplatin. However, Bcl-2 regulation on cisplatin treatment in human cancers is unknown. Here, we show a novel mechanism by which cisplatin treatment promotes resistance by increasing the expression of Bcl-2 mRNA. Bcl-2 mRNA and protein expression was increased in cisplatin-resistant endometrial cancer cell lines (KLE and HEC-1-A), but not in cisplatin-sensitive cell line (Ishikawa). Cisplatin-mediated increase in Bcl-2 expression was blocked by combination with either actinomycin D or cycloheximide. In addition, Bcl-2 inhibition by HA14-1 led to increased cisplatin-induced apoptosis in KLE and HEC-1-A, whereas Bcl-2 overexpression in Ishikawa led to decreased cisplatin-induced apoptosis. Inhibition of protein kinase C (PKC) activity prevented cisplatin-dependant increase in Bcl-2 mRNA, and induced apoptosis in KLE cells. Furthermore, PKC inhibition was associated with decreased Akt and NF-κB activity. Cells stably expressing shRNA for Akt isoforms revealed that Akt2 was involved in cisplatin-dependant increase in Bcl-2 and apoptosis. Overexpression of Akt2 in Akt2-deficient cells led to increased Bcl-2 expression on cisplatin treatment. Our data suggest a novel regulation pathway of Bcl-2 by cisplatin, via the activation of PKC and Akt2, which has a profound impact on resistance to cisplatin-induced apoptosis in endometrial cancer cells.

Curcumin, the golden spice from Indian saffron, is a chemosensitizer and radiosensitizer for tumors and chemoprotector and radioprotector for normal organs

Curcumin (diferuloylmethane), the yellow pigment in Indian saffron (Curcuma longa; also called turmeric, haldi, or haridara in the East and curry powder in the West), has been consumed by people for centuries as a dietary component and for a variety of proinflammatory ailments. Extensive research within the last decade in cell culture and in rodents has revealed that curcumin can sensitize tumors to different chemotherapeutic agents including doxorubicin, 5-FU, paclitaxel, vincristine, melphalan, butyrate, cisplatin, celecoxib, vinorelbine, gemcitabine, oxaliplatin, etoposide, sulfinosine, thalidomide, and bortezomib. Chemosensitization has been observed in cancers of the breast, colon, pancreas, gastric, liver, blood, lung, prostate, bladder, cervix, ovary, head and neck, and brain and in multiple myeloma, leukemia, and lymphoma. Similar studies have also revealed that this agent can sensitize a variety of tumors to gamma radiation including glioma, neuroblastoma, cervical carcinoma, epidermal carcinoma, prostate cancer, and colon cancer. How curcumin acts as a chemosensitizer and radiosensitizer has also been studied extensively. For example, it downregulates various growth regulatory pathways and specific genetic targets including genes for NF-κB, STAT3, COX2, Akt, antiapoptotic proteins, growth factor receptors, and multidrug-resistance proteins. Although it acts as a chemosensitizer and radiosensitizer for tumors in some cases, curcumin has also been shown to protect normal organs such as liver, kidney, oral mucosa, and heart from chemotherapy and radiotherapy-induced toxicity. The protective effects of curcumin appear to be mediated through its ability to induce the activation of NRF2 and induce the expression of antioxidant enzymes (e.g., hemeoxygenase-1, glutathione peroxidase, modulatory subunit of gamma-glutamyl-cysteine ligase, and NAD(P)H:quinone oxidoreductase 1, increase glutathione (a product of the modulatory subunit of gamma-glutamyl-cysteine ligase), directly quench free radicals, and inhibit p300 HAT activity. These preclinical studies are expected to lead to clinical trials to prove the potential of this age-old golden spice for treating cancer patients.

Inhibition of nuclear factor kappa B transcription activity drives a synergistic effect of pyrrolidine dithiocarbamate and cisplatin for treatment of renal cell carcinoma

One of the impeding factors in the effective treatment of metastatic renal cell carcinoma (RCC) is their intrinsic and acquired resistance to chemotherapeutics. Many studies have shown that drug resistance, at least in part, is mediated by the upregulation of anti-apoptotic (Bcl-2) and multidrug resistance molecules (MDR-1 and MRP-1) by the transcription factor nuclear factor kappa B (NF-kappaB). Combining NF-kappaB inhibitors with conventional chemotherapeutics could overcome resistance of cancer cells. In this study, we examined the synergistic effect of pyrrolidine dithiocarbamate (PDTC), a NF-kappaB inhibitor, and cisplatin, on two human metastatic RCC cell lines ACHN and SN12K1. Individual non-toxic concentrations of PDTC and cisplatin, when combined, synergistically induced a significant increase in apoptosis of the two RCC cell lines. In ACHN cells, the groups with nuclear translocation of NF-kappaB showed resistance to apoptosis, but in SN12K1 cells, the groups with NF-kappaB translocation were susceptible to apoptosis. The combination treatment significantly decreased the transcription activity of all NF-kappaB subunits in both cell lines. Anti-apoptotic proteins Bcl-2 and Bcl-(XL) were significantly decreased in the combination therapy group of both cell lines, but MDR-1 was decreased only in the ACHN cells. No changes in MRP-1 were observed in any of the treatment groups. The results demonstrate the potential of PDTC to be an adjunct therapeutic agent. The major mechanism of the synergistic effect appears to be mediated by the inhibition of transcription activity of NF-kappaB rather than its expression, and the resultant decrease in the anti-apoptotic proteins Bcl-2 and Bcl-(XL).

Enhancement of chemotherapeutic agent-induced apoptosis by inhibition of NF-kappaB using ursolic acid

NF-kappaB activation is known to reduce the efficiency of chemotherapy in cancer treatment. Ursolic acid, a minimally toxic compound, has shown the capability to inhibit NF-kappaB activation in living cells. Here, for the first time, we investigated the effects and mechanisms of NF-kappaB inhibition by ursolic acid on chemotherapy treatment (Taxol or cisplatin) of cancer. ASTC-a-1 (human lung adenocarcinoma), Hela (human cervical cancer) cells, primary normal mouse cells of lung and liver and mouse in vivo model were used. Activity of signal factors (NF-kappaB, Akt, Fas/FasL, BID, Bcl-2, cytochrome c and caspase-8, 3) was used to analyze the mechanisms of ursolic acid-chemo treatment. Ursolic acid-mediated suppression of NF-kappaB drastically reduced the required dosage of the chemotherapeutic agents to achieve identical biological endpoints and enhanced the chemotherapeutic agent-induced cancer cells apoptosis. Chemosensitization by ursolic acid in cancer cells was dependent on the amplified activation of intrinsic pathway (caspase-8-BID-mitochondria-cytochrome c-caspase-3) by augmentation of BID cleavage and activation of Fas/FasL-caspase-8 pathway. Prolonged treatment with relatively low doses of ursolic acid also sensitized cancer cells to the chemotherapeutic agents through suppression of NF-kappaB. Chemosensitization by ursolic acid was observed only in cancer cells, but not in primary normal cells. The inhibitive effect of ursolic acid on NF-kappaB was reversible, and the reversal was not accompanied by a loss in cells viability. By supplementing chemotherapy with minimally toxic ursolic acid, it is possible to improve the efficacy of cancer treatment by significantly reducing the necessary drug dose without sacrificing the treatment results.

Dexamethasone enhances trichosanthin-induced apoptosis in the HepG2 hepatoma cell line

AIMS

Trichosanthin (TCS) is a type I ribosome-inactivating protein (RIP) with antitumor activities for various cancers. In this paper, we aimed to investigate whether dexamethasone, an important synthetic member of the glucocorticoid steroids, in combination with TCS can be a potential therapy in treating hepatoma.

MAIN METHODS

Cell viability was investigated using MTT assay, and apoptosis was evaluated with Hoechst 33258 staining. Western blot analysis was used to examine the changes in the expression levels of IkappaB-alpha, NF-kappaB p65 subunit and Cox-2. Additionally, we took advantage of dominant-negative IkappaB (IkappaB-DM) over-expression and chemical inhibitor PDTC to inhibit NF-kappaB activation.

KEY FINDINGS

Our results demonstrated that dexamethasone could enhance TCS-induced apoptosis in the hepatoma cell line HepG2, decreasing IC50 values from in excess of 200microg/ml to 50microg/ml. In addition, our results demonstrated that TCS could induce rapid degradation of IkappaB-alpha, nuclear translocation of NF-kappaB and decrease of COX-2 expression in HepG2 cells. Inhibition of NF-kappaB by biological (IkappaB-DM) or chemical inhibitor (PDTC) increased HepG2 cells' sensitivity to TCS, resulting in cell viability rate decreasing and apoptotic rate increasing. Simultaneously, dexamethasone increased the level of IkappaB-alpha protein and effectively inhibited TCS-induced degradation of IkappaB-alpha.

SIGNIFICANCE

These results suggest that dexamethasone could enhance trichosanthin-induced apoptosis in the HepG2, at least in part, by inhibiting the NF-kappaB signaling pathway and thus strengthening the antitumor effects of TCS, which highlights the possibility of combined drug application of TCS and dexamethasone in the clinical treatment of hepatoma.