Clinical potential of inhibitors of survival pathways and activators of apoptotic pathways in treatment of cervical cancer: changing the apoptotic balance

Cisplatin causes erectile dysfunction by decreasing endothelial and smooth muscle content and inducing cavernosal nerve senescence in rats

INTRODUCTION

Cisplatin (cis-diamminedichloroplatinum II, CDDP), a drug widely used for cancer worldwide, may affect erectile function, but its side effects have not received enough attention. To investigate the effect of CDDP on erectile function and its possible mechanism.

METHODS

Sprague-Dawley rats were intraperitoneally administered CDDP (CDDP group) or the same volume of normal saline (control group). Erectile function was evaluated after a one-week washout. Then, histologic changes in the corpus cavernosum and cavernous nerve (CN) were measured. Other Sprague-Dawley rats were used to isolate the major pelvic ganglion and cavernous nerve (MPG/CN). RSC96 cells were then treated with CDDP. SA-β-gal staining was used to identify senescent cells, and qPCR was used to detect the senescence-associated secretory phenotype (SASP). Finally, the supernatant of RSC96 cells was used to culture MPG/CN. Erectile function was measured after administration of CDDP. The cavernosum levels of α-SMA, CD31, eNOS, and γ-H2AX, the apoptosis rate and the expression of p16, p21 and p53 in CN were also assayed. The senescent phenotype of RSC96 cells treated with CDDP was identified, and neurite growth from the MPG/CN was photographed and measured.

RESULTS

The CDDP group had a significantly lower ICP/MAP ratio than the control group. Compared to the control group, the CDDP group exhibited significantly lower α-SMA, CD31 and eNOS levels and significantly higher γ-H2AX and apoptosis rates in corpus cavernosum. In addition, CDDP increased some senescence markers p16, p21 and p53 in CN. In vitro, CDDP induced RSC96 senescence and SASP, and the supernatant of senescent cells slowed neurite outgrowth of MPG/CN.

DISCUSSIONS

CDDP treatment could induce erectile dysfunction, by affecting the content of endothelial and smooth muscle and causing SASP in CN. The results indicate that CDDP treatment should be considered as a risk factor for ED. Clinicians should pay more attention to the erectile function of cancer patients who receive CDDP treatment.

An Overview of Novel Agents for Cervical Cancer Treatment by Inducing Apoptosis: Emerging Drugs Ongoing Clinical Trials and Preclinical Studies

As the leading cause of cancer death, cervical cancer ranks fourth for both incidence and mortality. Cervical cancer incidence and mortality rates have reportedly decreased over the last decades thanks to extensive screening and widespread vaccination against human papilloma virus. However, there have been no major improvements concerning platinum-based chemotherapy on the survival of advanced cervical cancer. Thus, novel agents are urgently needed for the improvement of therapeutic effect. With the development of molecular biology and genomics, targeted therapy research has achieved a breakthrough development, including anti-angiogenesis, immune checkpoint inhibitors, and other treatments that are efficient for treatment of cervical cancer. Apoptosis is a crucial process for tumor progression. Drugs directed at inducing tumor-cell apoptosis are regarded as important treatment modalities. Besides, a number of novel compounds synthesized or derived from plants or microorganisms exhibited prominent anti-cancer activity by changing the apoptotic balance in cervical cancer. In this review, we summarized new target therapy drugs ongoing clinical trials that are used for treatment of cervical cancer. Further, we classified novel agents with a focus on improvement of therapeutic effect pre-clinically. To summarize, we also discussed application prospects of the new uses of old drugs and drug combinations, to provide researchers with new ideas for cervical cancer treatment.

Involvement of p53-dependent apoptosis signal in antitumor effect of Colchicine on human papilloma virus (HPV)-positive human cervical cancer cells

Colchicine, a plant-derived alkaloid with relatively low toxicity on normal human epidermal keratinocytes (HEKn), has selective inhibitory effect on the growth of CaSki (HPV16-positive) and HeLa (HPV18-positive) human cervical cancer cell lines via the induction of apoptosis. Colchicine (2.5, 5.0 and 10.0 ng/ml) significantly reduced the expression of human papilloma virus (HPV) 16 E6/E7 mRNA and protein in CaSki and HeLa cells. Moreover, reduced expression of E6 and E7 induced by Colchicine resulted in the up-regulation of tumor suppressor proteins, p53 and Rb, as well as down-regulation of phospho Rb (pRb) protein. In addition, Bax, cytosolic cytochrome c and cleaved caspase-3 protein were increased while Bcl-2 protein was decreased significantly by 48 h of Colchicine treatment. These results implied that Colchicine could be explored as a potent candidate agent for the treatment and prevention of HPV-associated cervical cancer without deleterious effects.

MAPK4 deletion enhances radiation effects and triggers synergistic lethality with simultaneous PARP1 inhibition in cervical cancer

BACKGROUND

Cervical cancer is one of the most common cancers among females worldwide and advanced patients have extremely poor prognosis. However, adverse reactions and accumulating resistance to radiation therapy require further investigation.

METHODS

The expression levels of mitogen-activated protein kinase 4 (MAPK4) mRNA were analyzed by real-time PCR and its association with overall survival was analyzed using Kaplan-Mier method. Colony formation, immunofluorescence and western blotting were used to examine the effects of MAPK4 knockout or over-expression on cervical cancer cells after radiation treatment. Drug-sensitivity of cervical cancer cells to PARP1 inhibitors, olaparib or veliparib, was analyzed by CCK-8 cell viability assays, and the 50% inhibitory concentration (IC50) was quantified using GraphPad Prism. The functional effects of MAPK4 knockout on the sensitivity of cervical cancer to radiation treatment and PARP1 inhibitors were further examined using xenograft tumor mouse models in vivo.

RESULTS

Cervical cancer patients with high MAPK4 mRNA expression have lower survival rate. After radiation treatment, the colony number of MAPK4 knockout cells was markedly reduced, and the markers for DNA double-chain breakage were significantly up-regulated. In addition, MAPK4 knockout reduced protein kinase B (AKT) phosphorylation, whereas its over-expression resulted in opposite effects. In MAPK4 KO cells with irradiation treatment, inhibition of AKT phosphorylation promoted DNA double-chain breakage. Constitutive activation of AKT (CA-AKT) increased the levels of phosphorylated-AKT (p-AKT), and DNA repair-related proteins, phosphorylated-DNA-dependent protein kinase (p-DNA-PK) and RAD51 recombinase (RAD51). Furthermore, MAPK4 knockout was found to affect the sensitivity of cervical cancer cells to poly ADP-ribose polymerase 1 (PARP1) inhibitors by activating the phosphorylation of AKT. Moreover, in vivo results demonstrated that MAPK4 knockout enhanced the sensitivity of cervical cancer to radiation and PARP1 inhibitors in mouse xenograft models.

CONCLUSIONS

Collectively, our data suggest that combined application of MAPK4 knockout and PARP1 inhibition can be used as therapeutic strategy in radiation treatment for advanced cervical carcinoma.

Melatonin increases human cervical cancer HeLa cells apoptosis induced by cisplatin via inhibition of JNK/Parkin/mitophagy axis

Considering that chemotherapy resistance is vital to the progression of cervical carcinoma, emerging researchers are focused on developing anti-tumor drugs to assist the treatment efficiency of chemotherapy. Melatonin has anti-tumor activity via several mechanisms including its anti-proliferative and pro-apoptotic effects as well as its potent pro-oxidant action in tumor cells. Therefore, melatonin may be useful for the treatment of tumors in association with chemotherapy drugs. Here, we studied the effect and mechanism of melatonin on HeLa cells apoptosis under cisplatin (CIS) treatment, particularly focusing on the caspase-9-related apoptosis pathway and mitophagy-mediated anti-apoptotic mechanism. The result indicated that co-stimulation of HeLa cells with CIS in the presence of melatonin further increased cellular apoptosis. Furthermore, concomitant treatments with melatonin and CIS significantly enhanced the mitochondrial structure and function damage, substantially augmented the caspase-9-dependent mitochondrial apoptosis with evidenced by lower mitochondria membrane potential, higher mitochondria ROS, and more pro-apoptotic proteins compared to the treatment with CIS alone. Mechanistically, melatonin inactivated mitophagy via blockade of JNK/Parkin, leading to the inhibition of anti-apoptotic mitophagy. The mitophagy had the ability to clear and remove damaged mitochondria, impairing CIS-mediated mitochondrial apoptosis. Activation of JNK/Parkin could alleviate the lethal effect of melatonin on HeLa cells. In summary, this study confirmed that melatonin sensitizes human cervical cancer HeLa cells to CIS-induced apoptosis through inhibition of JNK/Parkin/mitophagy pathways.

RIPK3 expression in cervical cancer cells is required for PolyIC-induced necroptosis, IL-1α release, and efficient paracrine dendritic cell activation

Previous studies have shown that cervical cancer cells only release low levels of pro-inflammatory cytokines owing to infection with human papillomaviruses. This results in low immunogenicity of the cancer cells. The viral dsRNA analog PolyIC has been suggested as a promising adjuvant for cervical cancer immunotherapy. However, little is known about the molecular requirements resulting in successful immune activation. Here, we demonstrate that stimulation of cervical cancer cells with PolyIC induced necroptotic cell death, which was strictly dependent on the expression of the receptor-interacting protein kinase RIPK3. Necroptotic cancer cells released interleukin-1α (IL-1α), which was required for powerful activation of dendritic cells (DC) to produce IL-12, a cytokine critical for anti-tumor responses. Again both, IL-1α release and DC activation, were strictly dependent on RIPK3 expression in the tumor cells. Of note, our in situ analyses revealed heterogeneous RIPK3 expression patterns in cervical squamous cell carcinomas and adenocarcinomas. In summary, our study identified a novel RIPK3-dependent mechanism that explains how PolyIC-treatment of cervical cancer cells leads to potent DC activation. Our findings suggest that the RIPK3 expression status in cervical cancer cells might critically influence the outcome of PolyIC-based immunotherapeutic approaches and should therefore be assessed prior to immunotherapy.

Downregulation of Foxc2 enhances apoptosis induced by 5-fluorouracil through activation of MAPK and AKT pathways in colorectal cancer

The chemotherapy drug 5-fluorouracil (5-FU) is fundamental for the treatment of colorectal cancer (CRC); however, drug resistance to 5-FU may occasionally occur. Abnormal expression of Forkhead box C2 gene (Foxc2) has been identified in several human cancers, but the role of Foxc2 in the progression of CRC remains unclear. The present study established a stable Foxc2-short hairpin (sh)RNA cell line, which was confirmed by western blot analysis and quantitative polymerase chain reaction. The Foxc2-shRNA cells were treated with 5-FU and the cell viability was determined by an MTT assay. Western blot analysis was performed to investigate the signaling pathway involved in 5-FU treatment. The present study identified that 5-FU increased the percentage of apoptotic CRC cells among the Foxc2/RNA interference-transfected cells compared with cells transfected with an empty vector. Therefore, the downregulation of Foxc2, induced by 5-FU, may enhance apoptosis by the downregulation of apoptotic factors, including B cell lymphoma-2 and pro-caspase-3, in Foxc2-shRNA CRC cells. Furthermore, the mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinases/protein kinase B (PI3K/AKT) pathways were essential for the sensitization effect of Foxc2 to 5-FU treatment. Overall, these findings reveal the mechanisms behind Foxc2 depletion and 5-FU treatment of CRC and suggest that Foxc2 enhances resistance to apoptosis, induced by 5-FU, through the activation of MAPK and P13K/AKT pathways, and may serve as a valuable clinical prognostic marker for CRC.

The association of apoptotic protein expressions sensitive to apoptosis gene, p73 and p53 with the prognosis of cervical carcinoma

Objective

To evaluate the expressions of several apoptotic pathway proteins in relation to clinical parameters and survival in patients with cervical carcinoma.

Methods

A total of 20 patients with clinically advanced staged carcinoma of cervix (International Federation of Gynecology and Obstetrics [FIGO] stage IIB-IVA) aged from 40 to 75 years were included in this study. The expression profile of anti-apoptotic protein (sensitive to apoptosis gene [SAG]), mitochondrial apoptotic proteins (B-cell lymphoma-extra-large [Bcl-xL] and Bcl-2 homologous antagonist/killer [Bak]), and tumor suppressor proteins (p73 and p53) were examined by real-time polymerase chain reaction experiments along with their relation to clinical parameters and survival analyses during follow-up for 5 to 8 years.

Results

No significant difference was found in the expressions of SAG, Bcl-xL, Bak, p73 and p53 proteins with respect to stage and grade of tumor. A significant positive correlation was noted between SAG and Bcl-xL genes (r=0.752, P<0.001) and between SAG and Bak genes (r=0.589, P=0.006). Among genes determined to be significantly associated with overall survival in the univariate analysis (P=0.026 for SAG, P=0.002 for Bcl-xL, and P=0.027 for p53), only p53 was identified as the significant predictor in the multivariate analysis (hazard ratio: 8.53, 95% confidence interval: 1.34–54.2, P=0.023).

Conclusion

In conclusion, our findings demonstrated a reverse correlation of SAG, Bcl-xL, and p53 expressions with overall survival of patients. No association of apoptotic pathway proteins with clinicopathological characteristics of cervical carcinoma patients was noted. Low SAG, Bcl-xL, and p53 expression levels revealed to be useful as prognostic predictors in patients with cervical carcinoma.

Expression of TRF2 and its prognostic relevance in advanced stage cervical cancer patients

Background

Telomeres are protective caps consisted of specific tandem repeats (5′-TTAGGG-3′). Shortening of telomeres at each cell division is known as “mitotic clock” of the cells, which renders telomeres as important regulators of lifespan. TRF2 is one of the critical members of shelterin complex, which is a protein complex responsible from the preservation of cap structure, and loss or mutation of TRF2 results in DNA damage, senescence or apoptosis. Since cancer is frequently associated with aberrant cell cycle progression, defective DNA repair or apoptosis pathways, TRF2 could be one likely candidate for cancer therapy.

Here we investigated the prognostic role of TRF2 levels in cervical cancer patients. Fold-induction rates were evaluated with respect to median values after real-time PCR analysis. Overall survival, distant disease-free and local recurrence-free survival rates were calculated using Kaplan-Meier long rank test.

Results

Both five year overall- and disease-free survival rates were longer in patients with higher TRF2 expression compared to lower expression, but results were not statistically significant (69.2% vs 28.9%, respectively). Mean local recurrence-free survivals (LRF) were very close ( 58.6, CI: 44.3-72.9 vs 54.5, CI: 32.1-76.9 months) for high and low expressions, respectively. Cumulative proportion of LRF at the end of five year period was 76.9% for high and 57.1% for low TRF2 expression (P = 0.75). Statistically significant difference was found between survival ratios and Bcl-xL and p53 gene expressions, but not with TRF2. A respectable correlation between TRF2 expression and apoptosis along with distant metastasis was noted (P = 0.045 and 0.036, respectively). Additionally, high TRF2 expression levels had a positive impact in five year survival rate of stage IIIB-IVA patients (P = 0.04).

Conclusions

Our results support the role of TRF2 in apoptosis and imply a positive relation with distant metastases and survival in advanced stage patients. The remarkable difference in survival periods of patients with different TRF2 expressions suggest that TRF2 may be a candidate factor to estimate survival for cervical cancer, a preliminary observation which should further be verified with a larger cohort.

Nutlin-3 preferentially sensitises wild-type p53-expressing cancer cells to DR5-selective TRAIL over rhTRAIL

Background:

Tumour cell-selective activation of apoptosis by recombinant human TNF-related apoptosis-inducing ligand (rhTRAIL) is enhanced through co-activation of p53 by chemotherapeutic drugs. The novel anticancer agent nutlin-3 provides a promising alternative for p53 activation by disrupting the interaction between p53 and its negative feedback regulator MDM2.

Methods:

We examined whether nutlin-3 enhances apoptosis induction by rhTRAIL and the DR5-selective TRAIL variant D269H/E195R in wild-type p53-expressing ovarian, colon and lung cancer cell lines and in an ex vivo model of human ovarian cancer.

Results:

Nutlin-3 enhanced p53, p21, MDM2 and DR5 surface expression. Although nutlin-3 did not induce apoptosis, it preferentially enhanced D269H/E195R-induced apoptosis over rhTRAIL. Combination treatment potentiated the cleavage of caspases 8, 9, 3 and PARP. P53 and MDM2 siRNA experiments showed that this enhanced apoptotic effect was mediated by wild-type p53. Indeed, nutlin-3 did not enhance rhTRAIL-induced apoptosis in OVCAR-3 cells harbouring mutant p53. Addition of the chemotherapeutic drug cisplatin to the combination further increased p53 and DR5 levels and rhTRAIL- and D269H/E195R-induced apoptosis. As a proof of concept, we show that the combination of D269H/E195R, nutlin-3 and cisplatin induced massive apoptosis in ex vivo tissue slices of primary human ovarian cancers.

Conclusion:

Nutlin-3 is a potent enhancer of D269H/E195R-induced apoptosis in wild-type p53-expressing cancer cells. Addition of DNA-damaging agents such as cisplatin further enhances DR5-mediated apoptosis.

Enhanced killing of cervical cancer cells by combinations of methyl jasmonate with cisplatin, X or alpha radiation

Current therapies for treatment of advanced cervical cancer involve the use of cisplatin, often in combination with radiotherapy. These treatments do not lead to a high survival rate and furthermore, serious side effects are dose-limiting factors. Methyl jasmonate (MJ) was recently identified as potent and selective cytotoxic agent towards cervical cancer cells. In the present study we evaluated the effectiveness of combined treatments of MJ with cisplatin or X-irradiation on a variety of cervical cancer cells including SiHa, CaSki, HeLa and C33A. Cytotoxicity of alpha particles, emitted from (224)Ra atoms, was also evaluated as a single agent and in combination with MJ. Cooperation between MJ and cisplatin in reducing cell viability (XTT assays) and survival (clonogenicity assays) was exhibited towards several cancer cell lines at a range of combination doses. MJ effectively cooperated also with X-ray irradiation, significantly lowering the radiation doses required to inhibit cell survival (ID50) of all tested cells lines. We show for the first time, that alpha irradiation selectively reduced cell viability and survival of cervical cancer cells. Lower doses of α irradiation were required as compared to X-irradiation to inhibit cell survival. Cooperation with MJ was demonstrated in part of the cancer cell lines. In conclusion, our studies point to α irradiation and MJ, novel anticancer agents, as potent candidates for treatment of cervical cancer, in single agent regiments and in combination. MJ can be added also to conventional X-ray and cisplatin therapies to increase their cytotoxic effect while lowering the effective dose.

Methyl jasmonate reduces the survival of cervical cancer cells and downregulates HPV E6 and E7, and survivin

The present study further investigated the mode of action of methyl jasmonate (MJ) in different cervical cancer cell lines. We show that in addition to the short term cytotoxicity, MJ effectively reduced the survival of cervical cancer cells (clonogenicity assays). MJ induced apoptosis in all cervical cancer cells. In some cell lines, MJ caused elevation of the mitochondrial superoxide anion, notably, in HeLa and CaSki. Changes in the expression of p53 and bax were variable, yet, downregulation of survivin was common to all cervical cancer cells. MJ significantly reduced the levels of the human papillomavirus (HPV) E6 and E7 proteins without alteration of the mRNA levels. Moreover, ectopic expression of E6, E7 or both in cervical cancer cells that lack HPV (C33A), did not alter significantly their response to MJ. Our studies point to MJ as an effective anticancer agent against a variety of cervical cancer cells acting through shared and different pathways to induce cell death regardless of the presence of HPV.

Expression of epidermal growth factors and apoptosis markers in pancreatic ductal adenocarcinoma

BACKGROUND

Epidermal growth factor family members: EGF, EGFR and the c-erbB-2(HER-2/neu) are involved in the growth of pancreatic ductal carcinoma, its invasiveness and metastases. Similarly, proteins regulating apoptosis can influence the development of pancreatic cancer. The aim of our study was to assess the expressions of EGF, EGFR, c-erbB-2, Bax and Bcl-xL in comparison with anatomo-clinical parameters. We also analyzed the relationship between the epidermal growth factors and apoptosis-regulating proteins.

MATERIALS AND METHODS

The levels of these proteins were determined immunohistochemically in 29 pancreatic ductal carcinoma cases.

RESULTS

We found no correlation of EGF, EGFR, c-erbB-2, Bax and Bcl-xL with age and gender of patients, or histological type and grade of malignancy (G). However, we observed a very strong correlation between EGF, EGFR, Bax, Bcl-xL and lymph node metastases (p=0.000, p=0.001, p=0.008, p=0.012, respectively) and between EGF, EGFR and distant metastases (p=0.002, p=0.008, respectively). Moreover, we found a correlation between Bcl-xL and c-erbB-2 (p=0.030) and between EGF and Bax (p=0.041).

CONCLUSIONS

These investigations seem to suggest that both epidermal growth factors (EGF, EGFR) and apoptosis-regulating proteins (Bax and Bcl-xL) play an essential role in lymph node involvement. Moreover EGF and EGFR are involved in distant metastases. The apoptosis markers appear to cooperate with epidermal growth factor proteins in the process of tumor spread.

Aberrant DNA methylation of apoptotic signaling genes in patients responsive and nonresponsive to therapy for cervical carcinoma

OBJECTIVE

We sought to investigate CpG-island methylation profiling of apoptotic genes apoptotic protease activating factor 1, caspase 8, death-associated protein kinase (DAPK), tumor necrosis factor receptor superfamily member 6 (FAS), Survivin, and tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and its role in resistance to therapy in cervical cancer (CXCA).

STUDY DESIGN

Methylation status was performed in 85 CXCA patients comprising therapeutic nonresponses and responses using methylation-specific polymerase chain reaction.

RESULTS

Methylation frequency of DAPK and FAS showed a statistically significant difference between therapeutic nonresponses and responses. Concurrent methylation of multiple apoptotic genes was a preferential event in CXCA. Moreover, concerted methylation of pair genes was observed in DAPK, FAS, and tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and found only in nonresponses.

CONCLUSION

Aberrant methylation of apoptotic signaling genes results in acquired resistance to therapy. Detection of methylation in apoptotic signaling genes is potentially useful as a molecular predictive marker for strategic planning of treatment efficacy and evaluation of therapeutic outcome in CXCA, leading to an improvement of patients' survival.

Regulation of cell growth through cell cycle arrest and apoptosis in HPV 16 positive human cervical cancer cells by tea polyphenols

Cervical cancer is the second most common malignant neoplasm in women, in terms of both incidence and mortality rates worldwide. The polyphenolic constituents of tea (Camellia sinensis) have gained considerable attention because of its anti-cancer properties against a variety of cancers. Here we studied the effects of green and black tea polyphenols (GTP and BTP), on cellular proliferation and cell death in the SiHa cells (human cervical cancer) expressing the human papilloma virus (HPV)-16. The result showed that both GTP and BTP inhibited proliferation of cells in dose and time dependent manner. Cell cycle analysis showed anti-proliferative effect of GTP which is associated with an increase in the G2/M phase and apoptotic effect of BTP in 24 h treated SiHa cells. Further, on increase of incubation time for 48 h, GTP caused induction of apoptosis up to 20% of SiHa cells. The role GTP and BTP in apoptosis was further confirmed by reduction in mitochondrial membrane potential and increased levels of membrane phosphatidylserine. Thus, our data suggests that tea polyphenols exhibit anti-cancer potential against cervical cancer by inhibition of cell growth and induction of apoptosis.

Flavonoids as RTK inhibitors and potential anticancer agents

Tyrosine kinase receptors (RTKs) play a crucial role in the regulation of the cell division cycle. Currently more than 50 RTKs divided into several subfamilies have been described. The inhibition of these enzymes has emerged as an important research-area. Compounds able to inhibit the activity of these enzymes are expected to display antiproliferative properties. Flavonoids are representative of various small molecules acting as RTK inhibitors. These naturally occurring compounds are able to bind to the ATP-binding site of several kinases. The most plausible current hypothesis explaining the action of these substances on kinases is that the chromenone moiety of the flavonoid acts as a mimetic of the adenine moiety of ATP, the receptor co-factor. In this review, we report recent results on the activity of natural and synthetic derivatives of flavonoids as inhibitors of RTKs. Mechanistic aspects, the therapeutic usefulness, and the potential clinical use are discussed.

Correlating EGFR expression with receptor-binding properties and internalization of 64Cu-DOTA-cetuximab in 5 cervical cancer cell lines

The anti-epidermal growth factor receptor (anti-EGFR) antibody cetuximab is clinically approved for the treatment of EGFR-expressing metastatic colorectal cancer and advanced head and neck cancer. Overexpression of EGFR has also been found in more than 70% of carcinomas of the cervix. The overall goal of this study was to determine whether (64)Cu-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-cetuximab has potential as an agent for measuring EGFR concentration by PET imaging in cervical cancer tumors.

METHODS

Cetuximab was conjugated to the bifunctional chelator DOTA and labeled with (64)Cu. EGFR messenger RNA (mRNA) expression was correlated with EGFR densities on the cell surface of 5 different cervical cancer cell lines and with receptor function, measured by internalization of (64)Cu-DOTA-cetuximab. Imaging in tumor-bearing mice with small-animal PET was performed using the highest-expressing cervical cancer cell line.

RESULTS

The affinity of (64)Cu-DOTA-cetuximab binding for the EGFR was similar in 4 EGFR-positive lines, varying from 0.1 to 0.7 nM. The mRNA expression corresponded well with EGFR densities and levels of internalization, with responses decreasing in the order of CaSki>ME-180>DoTc2 4510>HeLa>C-33A. Biodistribution and small-animal PET studies with (64)Cu-DOTA-cetuximab in CaSki tumor-bearing nude mice showed relatively high tumor uptake at 24 h after injection (13.2+/-1.2 percentage of injected activity per gram), although there was also significant retention of activity in the blood and liver accumulation.

CONCLUSION

(64)Cu-DOTA-cetuximab was successfully used to detect and quantify EGFR expression in cervical cancer tumors, and small-animal PET/CT of EGFR-expressing CaSki tumors suggests potential for PET/CT of EGFR-positive tumors.

Methyl jasmonate induces cell death with mixed characteristics of apoptosis and necrosis in cervical cancer cells

In the present study the effectiveness of methyl jasmonate (MJ) against cervical cancer cell lines was investigated. We show that MJ is cytotoxic to a range of cervical cancer lines including SiHa, CaSki and HeLa that carry human papillomavirus (HPV) DNA and wild type p53, and C33A that is negative for HPV and contains mutant p53. Primary human foreskin keratinocytes were almost resistant to the drug. Cytotoxicity of MJ was dose and time dependent, and associated mainly with the induction of cell death and to a less extent with inhibition of cell growth. Cell death induced by MJ displayed features characteristic to both apoptosis and necrosis, and was associated with different changes in the levels of p53, p21, bcl-2 and bax in the various cervical cancer lines. In conclusion, MJ a novel anticancer agent, acts via multiple pathways to induce death of cervical cancer cells, thus making it a promising candidate for treatment of cervical cancer.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its therapeutic potential in breast and gynecologic cancers

OBJECTIVE

The relationship between the apoptotic pathway and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising area of scientific interest for cancer researchers. TRAIL-receptor-activating agents have demonstrated favorable in vitro and in vivo activity for the treatment of several malignancies including breast and gynecologic cancers.

METHODS

This article reviews the available peer-reviewed literature and our own institution's experience with specific TRAIL-receptor-activating agents. Emphasis was placed on the apoptotic/TRAIL mechanism, preclinical evaluation, and phase I studies in various malignancies.

RESULTS

Preclinical and early phase I studies indicate that these novel agents are safe with enhanced target specificity for malignancy. When these targeted agents are combined with conventional chemotherapy drugs or radiation therapy, they appear to increase cell death over single-agent modalities.

CONCLUSIONS

TRAIL-receptor-activating agents represent an exciting new class of targeted therapies that hold promise to improve the treatment of women with breast and gynecologic malignancies.

Inhibitors of metabolism rescue cell death in Huntington's disease models

Huntington's disease (HD) is a fatal inherited neurodegenerative disorder. HD is caused by polyglutamine expansions in the huntingtin (htt) protein that result in neuronal loss and contribute to HD pathology. The mechanisms of neuronal loss in HD are elusive, and there is no therapy to alleviate HD. To find small molecules that slow neuronal loss in HD, we screened 1,040 biologically active molecules to identify suppressors of cell death in a neuronal cell culture model of HD. We found that inhibitors of mitochondrial function or glycolysis rescued cell death in this cell culture and in in vivo HD models. These inhibitors prevented cell death by activating prosurvival ERK and AKT signaling but without altering cellular ATP levels. ERK and AKT inhibition through the use of specific chemical inhibitors abrogated the rescue, whereas their activation through the use of growth factors rescued cell death, suggesting that this activation could explain the protective effect of metabolic inhibitors. Both ERK and AKT signaling are disrupted in HD, and activating these pathways is protective in several HD models. Our results reveal a mechanism for activating prosurvival signaling that could be exploited for treating HD and possibly other neurodegenerative disorders.

NF-kappaB and apoptosis in colorectal tumourigenesis

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) may play an important role in colorectal tumourigenesis, controlling cell cycle and apoptosis gene expression. In addition, imbalances between cell proliferation and cell death are thought to underlie neoplastic development. The aims of this study were to investigate apoptosis and expression of several apoptosis-related proteins, and to determine correlations with colorectal tumour progression.

MATERIALS AND METHODS

Apoptosis was evaluated by the TUNEL assay in 48 patient samples, including adenomas, adenocarcinomas and adjacent normal mucosas. Immunohistochemistry was performed for Bcl-2 and NF-kappaB. Expression levels of p53, Bax and IkappaB proteins were determined by immunoblotting. Cultured human colon cancer cells were used to evaluate NF-kappaB expression and nuclear translocation by immunocytochemistry and immunoblotting.

RESULTS

Apoptosis and NF-kappaB immunoreactivity were significantly higher in tumour tissue compared with normal mucosa (P < 0.01), increasing in association with histological tumour progression (P < 0.01). Bcl-2 was consistently higher in normal mucosa (P < 0.01) and inversely correlated with the percentage of apoptosis (P < 0.01). Phosphorylated p53 and Bax levels were similar in tumour tissue and normal mucosa; however, the NF-kappaB inhibitor, IkappaB, tended to decrease in tumours. In vitro, nuclear translocation of NF-kappaB was greater in proliferative than in resting phases of colon cancer cells.

CONCLUSIONS

NF-kappaB expression and apoptosis are increased from adenoma to poorly differentiated adenocarcinoma tissues. Apoptosis is correlated with suppression of Bcl-2 expression, but appears to proceed through a p53- and Bax-independent pathway. Activation of NF-kappaB may play an important role in colorectal tumour progression.

NF-kappaB and apoptosis in colorectal tumourigenesis

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) may play an important role in colorectal tumourigenesis, controlling cell cycle and apoptosis gene expression. In addition, imbalances between cell proliferation and cell death are thought to underlie neoplastic development. The aims of this study were to investigate apoptosis and expression of several apoptosis-related proteins, and to determine correlations with colorectal tumour progression.

MATERIALS AND METHODS

Apoptosis was evaluated by the TUNEL assay in 48 patient samples, including adenomas, adenocarcinomas and adjacent normal mucosas. Immunohistochemistry was performed for Bcl-2 and NF-kappaB. Expression levels of p53, Bax and IkappaB proteins were determined by immunoblotting. Cultured human colon cancer cells were used to evaluate NF-kappaB expression and nuclear translocation by immunocytochemistry and immunoblotting.

RESULTS

Apoptosis and NF-kappaB immunoreactivity were significantly higher in tumour tissue compared with normal mucosa (P < 0.01), increasing in association with histological tumour progression (P < 0.01). Bcl-2 was consistently higher in normal mucosa (P < 0.01) and inversely correlated with the percentage of apoptosis (P < 0.01). Phosphorylated p53 and Bax levels were similar in tumour tissue and normal mucosa; however, the NF-kappaB inhibitor, IkappaB, tended to decrease in tumours. In vitro, nuclear translocation of NF-kappaB was greater in proliferative than in resting phases of colon cancer cells.

CONCLUSIONS

NF-kappaB expression and apoptosis are increased from adenoma to poorly differentiated adenocarcinoma tissues. Apoptosis is correlated with suppression of Bcl-2 expression, but appears to proceed through a p53- and Bax-independent pathway. Activation of NF-kappaB may play an important role in colorectal tumour progression.

Association of epidermal growth factor receptor (EGFR) gene copy number amplification with neck lymph node metastasis in areca-associated oral carcinomas

Epidermal growth factor receptor (EGFR) has an important role in cell proliferation, differentiation, and transformation. Several alterations and activation of EGFR have been identified in tumors. Inhibitors that impair EGFR activity have been identified and studied for cancer therapy, so the present study was conducted to comprehensively assess the amplification, mutation, and expression of EGFR in areca-associated oral squamous cell carcinoma (OSCC), which might be beneficial for targeting therapy. Gene copy number amplifications of EGFR were identified in 33% (14/42) cases of OSCC. Six cases of OSCC had a high copy number amplification. Direct sequencing of PCR products of 20 representative cases of OSCC revealed no somatic mutation in the kinase domains of EGFR. Sixty-seven percent (28/42) of the OSCC cases had nuclear and/or cytosolic EGFR immunoreactivity. Significant increases in EGFR copy number and EGFR immunoreactivity were found in OSCC subjects compared with long-term areca chewers, or compared with match adjacent oral mucosa (P<0.0001 and P=0.029, respectively). Interestingly, OSCC with nodal involvement had significantly higher EGFR gene copy number than OSCC without nodal involvement (3.194+/-0.740 versus 1.733+/-0.246; P=0.050). Our data suggest that genomic amplification could be a genetic basis underlying activation of the EGFR pathway in areca-associated OSCC.

Epidermal growth factor can induce apoptosis in neuroblastoma

BACKGROUND/PURPOSE

In previous studies, incubation of doxorubicin-resistant neuroblastoma SK-N-SH (Dox-R) cells with epidermal growth factor (EGF) decreased extracellular signal-regulated kinase activation. Because extracellular signal-regulated kinase activation is associated with cell proliferation, we hypothesized that EGF could induce apoptosis and decrease the rate of cell growth in these cells.

METHODS

The growth of wild-type (WT) SK-N-SH and Dox-R cells after incubation with EGF concentrations ranging from 1 to 100 ng/mL was determined by a colorimetric assay. Apoptosis was assessed by Hoechst staining and DNA laddering in WT, Dox-R, and cisplatin-resistant cells treated with EGF (100 ng/mL). Cleaved caspase-3 and EGF receptor (human epidermal growth factor receptor [HER1-HER4]) expression were verified by Western blot and reverse transcriptase-polymerase chain reaction.

RESULTS

Epidermal growth factor decreased WT cell growth at concentrations between 50 and 100 ng/mL; Dox-R cell growth was attenuated at all EGF concentrations. Apoptosis was observed in WT and Dox-R cells incubated with EGF. Maximal cleaved caspase-3 expression occurred in WT cells treated with EGF 100 ng/mL and in Dox-R treated with EGF 5 to 10 ng/mL. Epidermal growth factor did not induce apoptosis in cisplatin-resistant cells. HER2 and HER3 transcription was maximal in WT and Dox-R cells, respectively.

CONCLUSIONS

Wild-type and Dox-R cells exhibited decreased cell growth after EGF treatment because of apoptosis. This involved caspase-3 activation and could work through HER2 and HER3 receptors.

Molecular targets in gynaecological cancers

The application of high throughput expression profiling and other advanced molecular biology laboratory techniques has revolutionised the management of cancers and is gaining attention in the field of gynaecological cancers. Such new approaches may help to improve our understanding of carcinogenesis and facilitate screening and early detection of gynaecological cancers and their precursors. Individualised prediction of patients' responses to therapy and design of personalised molecular targeted therapy is also possible. The studies of various molecular targets involved in the various signal pathways related to carcinogenesis are particularly relevant to such applications. At the moment, the application of detection and genotyping of human papillomavirus in management of cervical cancer is one of the most well established appliances of molecular targets in gynaecological cancers. Methylation, telomerase and clonality studies are also potentially useful, especially in assisting diagnosis of difficult clinical scenarios. This post-genomic era of clinical medicine will continue to make a significant impact in routine pathology practice. The contribution of pathologists is indispensable in analysis involving tissue microarray. On the other hand, both pathologists and bedside clinicians should be aware of the limitation of these molecular targets. Interpretation must be integrated with clinical and histopathological context to avoid misleading judgement. The importance of quality assurance of all such molecular techniques and their ethical implications cannot be over-emphasised.