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

Circulating and Endometrial Tissue microRNA Markers Associated with Endometrial Cancer Diagnosis, Prognosis, and Response to Treatment

In developed countries, endometrial cancer (EC) is one of the most common neoplasms of the female reproductive system. MicroRNAs (miRs) are a class of single-stranded noncoding RNA molecules with lengths of 19-25 nucleotides that bind to target messenger RNA (mRNA) to regulate post-transcriptional gene expression. Although there is a large amount of research focused on identifying miRs with a diagnostic, prognostic, or response to treatment capacity in EC, these studies differ in terms of experimental methodology, types of samples used, selection criteria, and results obtained. Hence, there is a large amount of heterogeneous information that makes it difficult to identify potential miR biomarkers. We aimed to summarize the current knowledge on miRs that have been shown to be the most suitable potential markers for EC. We searched PubMed and Google Scholar without date restrictions or filters. We described 138 miRs with potential diagnostic, prognostic, or treatment response potential in EC. Seven diagnostic panels showed higher sensitivity and specificity for the diagnosis of EC than individual miRs. We further identified miRs up- or downregulated depending on the FIGO stage, precursor lesions, and staging after surgery, which provides insight into which miRs are expressed chronologically depending on the disease stage and/or that are modulated depending on the tumor grade based on histopathological evaluation.

Targeting the anaphase-promoting complex/cyclosome (APC/C) enhanced antiproliferative and apoptotic response in bladder cancer

Improving the chemotherapy sensitivity of bladder cancer is a current clinical challenge. It is critical to seek out effective combination therapies that include low doses of cisplatin due to its dose-limiting toxicity. This study aims to investigate the cytotoxic effects of the combination therapy including proTAME, a small molecule inhibitor, targeting Cdc-20 and to determine the expression levels of several APC/C pathway-related genes that may play a role in the chemotherapy response of RT-4 (bladder cancer) and ARPE-19 (normal epithelial) cells. The IC20 and IC50 values were determined by MTS assay. The expression levels of apoptosis-associated (Bax and Bcl-2) and APC/C-associated (Cdc-20, Cyclin-B1, Securin, and Cdh-1) genes were assessed by qRT-PCR. Cell colonization ability and apoptosis were examined by clonogenic survival experiment and Annexin V/PI staining, respectively. Low-dose combination therapy showed a superior inhibition effect on RT-4 cells by increasing cell death and inhibiting colony formation. Triple-agent combination therapy further increased the percentage of late apoptotic and necrotic cells compared to the doublet-therapy with gemcitabine and cisplatin. ProTAME-containing combination therapies resulted in an elevation in Bax/Bcl-2 ratio in RT-4 cells, while a significant decrease was observed in proTAME-treated ARPE-19 cells. Cdc-20 expression in proTAME combined treatment groups were found to be decreased compared to their control groups. Low-dose triple-agent combination induced cytotoxicity and apoptosis in RT-4 cells effectively. It is essential to evaluate the role of APC/C pathway-associated potential biomarkers as therapeutic targets and define new combination therapy regimens to achieve improved tolerability in bladder cancer patients in the future.

Biological Activity of fac-[Re(CO)3(phen)(aspirin)], fac-[Re(CO)3(phen)(indomethacin)] and Their Original Counterparts against Ishikawa and HEC-1A Endometrial Cancer Cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) are inhibitors of cyclooxygenase enzyme (COX) and were found to have positive effects in reducing the risk of developing gynecological cancers. However, long-term administration of NSAIDs carries the risk of various side effects, including those in the digestive and circulatory systems. Therefore, there is a constant need to develop new NSAID derivatives. In this work, we investigated rhenium NSAIDs, comparing their effects on endometrial cancer cells with original NSAIDs, demonstrating the high activity of aspirin and indomethacin derivatives. The cytotoxic activity of rhenium derivatives against the Ishikawa and HEC-1A cancer cell lines was higher than that of the original NSAIDs. The IC50 after 24-h incubation of Ishikawa and HEC-1A were 188.06 µM and 394.06 µM for rhenium aspirin and 228.6 µM and 1459.3 µM for rhenium indomethacin, respectively. At the same time, IC50 of aspirin and indomethacin were 10,024.42 µM and 3295.3 µM for Ishikawa, and 27,255.8 µM and 5489.3 µM for HEC-1A, respectively. Moreover, these derivatives were found to inhibit the proliferation of both cell lines in a time- and state-dependent manner. The Ishikawa cell proliferation was strongly inhibited by rhenium aspirin and rhenium indomethacin after 72-h incubation (*** = p < 0.001), while the HEC-1A proliferation was inhibited by the same agents already after 24-h incubation (*** = p < 0.001). Furthermore, the ROS level in the mitochondria of the tested cells generated in the presence of rhenium derivatives was higher than the original NSAIDs. That was associated with rhenium indomethacin exclusively, which had a significant effect (*** = p < 0.001) on both Ishikawa and HEC-1A cancer cells. Rhenium aspirin had a significant effect (*** = p < 0.001) on the mitochondrial ROS level of Ishikawa cells only. Overall, the research revealed a high potential of the rhenium derivatives of aspirin and indomethacin against endometrial cancer cells compared with the original NSAIDs.

Dinaciclib, a Bimodal Agent Effective against Endometrial Cancer

Endometrial cancer (EC) is the sixth most prevalent female cancer globally and although high rates of success are achieved when diagnosed at an early stage, the 5-year survival rate for cancers diagnosed at Stages II-IV is below 50%. Improving patient outcomes will necessitate the introduction of novel therapies to the clinic. Pan-cyclin-dependent kinase inhibitors (CDKis) have been explored as therapies for a range of cancers due to their ability to simultaneously target multiple key cellular processes, such as cell cycle progression, transcription, and DNA repair. Few studies, however, have reported on their potential for the treatment of EC. Herein, we examined the effects of the pan-CDKi dinaciclib in primary cells isolated directly from tumors and EC cell lines. Dinaciclib was shown to elicit a bimodal action in EC cell lines, disrupting both cell cycle progression and phosphorylation of the RNA polymerase carboxy terminal domain, with a concomitant reduction in Bcl-2 expression. Furthermore, the therapeutic potential of combining dinaciclib and cisplatin was explored, with the drugs demonstrating synergy at specific doses in Type I and Type II EC cell lines. Together, these results highlight the potential of dinaciclib for use as an effective EC therapy.

Antitumor Effects of MRS5698, a Cordycepin Derivative, on Endometrial Cancer Cells

Endometrial cancer drug treatments often produce undesirable effects. Thus, discovering new drugs with fewer side effects is required. Cordycepin is a constituent of Cordyceps sinensis, which has been proven to inhibit tumor growth by stimulating the adenosine A3 receptor (A3R). However, cordycepin is rapidly degraded by adenosine deaminase (ADA) and has a clinically unacceptable short half-life. One of its derivatives, MRS5698, was predicted to exhibit antitumor effects with a poor affinity to ADA by our previous validated in silico experiments. The purpose of this study was to explore the possibilities of using MRS5698 as a novel antitumor agent through experiments on Ishikawa and HEC-1A cells. The detection of inhibition and apoptotic rate of MRS5698 and cisplatin, and their combination, on Ishikawa and HEC-1A cells were performed by MTT assays and flow cytometry, respectively. The inhibition rates of MRS5698 on Ishikawa and HEC-1A cells were both significantly higher than the control groups ( P < 0.05). MRS5698 produced a higher inhibitory effect on HEC-1A cells than on Ishikawa cells with IC50 values of 20.55 and 27.25 μg/mL, respectively. MRS5698 had a stronger inhibitory effect than cisplatin on HEC-1A cells. The Annexin V-FITC/propidium iodide assays demonstrated that the total rate of apoptosis of MRS5698 on HEC-1A cells was higher than that on Ishikawa cells. The results of MTT assay and cellular apoptosis showed that the combined use of MRS5698 and cisplatin produces dose-independent antagonistic effects. MRS5698 produced antitumor effects on both cell lines, which were better than that of cordycepin. However, the combined use of MRS5698 and cisplatin produced an antagonistic effect. A further in vivo study could be considered for investigating the antitumor effects of either MRS5698 monotherapy or MRS5698 in combination with other nonplatinum-based chemotherapeutic drugs in treating endometrial cancer.

Effect of monoacylglycerol lipase on the tumor growth in endometrial cancer

Aim

Abnormal lipid metabolism plays a dual role in tumorigenesis, specifically in the occurrence and development of cancers. Monoacylglycerol lipase (MAGL), a hydrolase that is important for lipid metabolism, plays a vital role in different aspects of tumorigenesis. Many studies have shown that MAGL is highly elevated in a variety of cancers and plays an active role. However, its potential role in supporting endometrial cancer (EC) growth and progression has not yet been explored in depth.

Methods

Immunohistochemistry and quantitative real‐time reverse transcription polymerase chain reaction were performed to estimate the protein and messenger RNA (mRNA) levels of MAGL in tumor tissues. Then, JZL184 and small interfering RNA (siRNA) were used to decrease the expression of MAGL in EC cells. The gene and protein expression levels of MAGL were measured using quantitative real‐time PCR and western blotting, respectively. Additionally, the effect of MAGL on tumor growth in EC was detected by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide , cell cycle and western blotting assay in vitro.

Results

We found that MAGL was overexpressed in EC and was significantly correlated with surgical‐pathological stage, myometrial invasion, number of pregnancies and body mass index. The growth and cell cycle progression of tumor cells were significantly impaired in vitro by the pharmacological and siRNA‐mediated MAGL inhibition. In addition, MAGL inhibition seemed to repress two target genes, Cyclin D1 and Bcl‐2.

Conclusion

In summary, we have demonstrated that MAGL is involved in EC growth and progression. Our results suggest that targeting MAGL may be a novel and valid treatment for EC.

Efp promotes in vitro and in vivo growth of endometrial cancer cells along with the activation of nuclear factor-κB signaling

Endometrial cancer is common among postmenopausal women and its incidence is increasing in developed countries. Considering that >80% of endometrial cancers are assumed to be estrogen-related, higher estrogen exposure will be relevant to tumorigenesis. Therefore, the roles of estrogen target genes will be important to understand the pathophysiological mechanisms. We previously revealed that estrogen-responsive RING finger protein Efp contributes to breast cancer progression through the protein degradation of cell cycle checkpoint 14-3-3σ. We and others also proposed that Efp has tumor-promoting activities in estrogen receptor (ER)-negative cancer cells. In addition, Efp plays a role in type I interferon production by activating antiviral signaling, which provokes nuclear factor-κB (NF-κB) signaling. In the present study, we investigate whether Efp plays a critical role in endometrial cancer biology. We show that siRNA-mediated Efp knockdown represses the proliferation and migration of endometrial cancer ER-positive Ishikawa and ER-negative HEC-1A cells. Efp knockdown increases 14-3-3σ protein levels and decreases the rates proliferative stage cells. Efp siRNA significantly inhibits the in vivo tumor growth of endometrial cancer cells in both subcutaneous and orthotopic xenograft models. Intriguingly, Efp knockdown represses NF-κB-dependent transactivation and transcription of target genes, such as IL6ST and IL18, in endometrial cancer cells. Overall, Efp would exert a tumor-promoting role through modulating NF-κB pathway and 14-3-3σ protein degradation in endometrial cancer regardless of its estrogen receptor status. Our results indicate that Efp could be a potential diagnostic and therapeutic target for endometrial cancer.

Endometrial Carcinoma: Specific Targeted Pathways

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Growth Hormone differentially modulates chemoresistance in human endometrial adenocarcinoma cell lines

Growth Hormone may influence neoplastic development of endometrial epithelium towards endometrial adenocarcinoma, which is one of the most occurring tumors in acromegalic patients. Since chemoresistance often develops in advanced endometrial adenocarcinoma, we investigated whether Growth Hormone might influence the development of chemoresistance to drugs routinely employed in endometrial adenocarcinoma treatment, such as Doxorubicin, Cisplatin, and Paclitaxel. Growth Hormone and Growth Hormone receptor expression was assessed by immunofluorescence in two endometrial adenocarcinoma cell lines, AN3 CA and HEC-1-A cells. Growth Hormone effects were assessed investigating cell viability, caspase3/7 activation, ERK1/2, and protein kinase C delta protein expression. AN3 CA and HEC-1-A cells display Growth Hormone and Growth Hormone receptor. Growth Hormone does not influence cell viability in both cells lines, but significantly reduces caspase 3/7 activation in AN3 CA cells, an effect blocked by a Growth Hormone receptor antagonist. Growth Hormone rescues AN3 CA cells from the inhibitory effects of Doxorubicin and Cisplatin on cell viability, while it has no effect on Paclitaxel. Growth Hormone does not influence the pro-apoptotic effects of Doxorubicin, but is capable of rescuing AN3 CA cells from the pro-apoptotic effects of Cisplatin. On the other hand, Growth Hormone did not influence the effects of Doxorubicin and Paclitaxel on HEC-1A cell viability. The protective action of Growth Hormone towards the effects of Doxorubicin may be mediated by ERK1/2 activation, while the pro-apoptotic effects of Cisplatin may be mediated by protein kinase C delta inhibition. All together our results indicate that Growth Hormone may differentially contribute to endometrial adenocarcinoma chemoresistance. This may provide new insights on novel therapies against endometrial adenocarcinoma chemoresistant aggressive tumors.

Common Chemical Inductors of Replication Stress: Focus on Cell-Based Studies

DNA replication is a highly demanding process regarding the energy and material supply and must be precisely regulated, involving multiple cellular feedbacks. The slowing down or stalling of DNA synthesis and/or replication forks is referred to as replication stress (RS). Owing to the complexity and requirements of replication, a plethora of factors may interfere and challenge the genome stability, cell survival or affect the whole organism. This review outlines chemical compounds that are known inducers of RS and commonly used in laboratory research. These compounds act on replication by direct interaction with DNA causing DNA crosslinks and bulky lesions (cisplatin), chemical interference with the metabolism of deoxyribonucleotide triphosphates (hydroxyurea), direct inhibition of the activity of replicative DNA polymerases (aphidicolin) and interference with enzymes dealing with topological DNA stress (camptothecin, etoposide). As a variety of mechanisms can induce RS, the responses of mammalian cells also vary. Here, we review the activity and mechanism of action of these compounds based on recent knowledge, accompanied by examples of induced phenotypes, cellular readouts and commonly used doses.

Chemoresistance and targeted therapies in ovarian and endometrial cancers

Gynecological cancers are known for being very aggressive at their advanced stages. Indeed, the survival rate of both ovarian and endometrial cancers is very low when diagnosed lately and the success rate of current chemotherapy regimens is not very efficient. One of the main reasons for this low success rate is the acquired chemoresistance of these cancers during their progression. The mechanisms responsible for this acquired chemoresistance are numerous, including efflux pumps, repair mechanisms, survival pathways (PI3K/AKT, MAPK, EGFR, mTOR, estrogen signaling) and tumor suppressors (P53 and Par-4). To overcome these resistances, a new type of therapy has emerged named targeted therapy. The principle of targeted therapy is simple, taking advantage of changes acquired in malignant cancer cells (receptors, proteins, mechanisms) by using compounds specifically targeting these, thus limiting their action on healthy cells. Targeted therapies are emerging and many clinical trials targeting these pathways, frequently involved in chemoresistance, have been tested on gynecological cancers. Despite some targets being less efficient than expected as mono-therapies, the combination of compounds seems to be the promising avenue. For instance, we demonstrate using ChIP-seq analysis that estrogen downregulate tumor suppressor Par-4 in hormone-dependent cells by directly binding to its DNA regulatory elements and inhibiting estrogen signaling could reinstate Par-4 apoptosis-inducing abilities. This review will focus on the chemoresistance mechanisms and the clinical trials of targeted therapies associated with these, specifically for endometrial and ovarian cancers.

Parasporin-2 from a New Bacillus thuringiensis 4R2 Strain Induces Caspases Activation and Apoptosis in Human Cancer Cells

In previous studies, parasporin-2Aa1, originally isolated from Bacillus thuringiensis strain A1547, was shown to be cytotoxic against specific human cancer cells but the mechanisms of action were not studied. In the present study, we found that proteinase K activated parasporin-2Aa1 protein isolated from a novel B. thuringiensis strain, 4R2, was specifically cytotoxic to endometrial, colon, liver, cervix, breast and prostate cancer. It showed no toxicity against normal cells. Upon treatment with proteinase K-activated parasporin-2Aa1, morphological changes were observed and western blot analysis revealed the cleavage of poly (ADP-Ribose) polymerase, caspase-3 and caspase-9 in cancer cell lines exclusively, indicative of programmed cell death, apoptosis. Flow cytometry analyses,using propidium iodide and annexin V, as well as a caspases 3/7 assay confirmed apoptosis induction. Further analyses were performed to study survival pathways, including AKT, XIAP, ERK1/2 and PAR-4, a known inducer of apoptosis. These results indicate that parasporin-2Aa1 is a selective cytotoxic protein that induces apoptosis in various human cancer cell lines from diverse tissues.

Chemoresistance is associated with increased cytoprotective autophagy and diminished apoptosis in bladder cancer cells treated with the BH3 mimetic (-)-Gossypol (AT-101)

Background

Acquired resistance to standard chemotherapy causes treatment failure in patients with metastatic bladder cancer. Overexpression of pro-survival Bcl-2 family proteins has been associated with a poor chemotherapeutic response, suggesting that Bcl-2-targeted therapy may be a feasible strategy in patients with these tumors. The small-molecule pan-Bcl-2 inhibitor (−)-gossypol (AT-101) is known to induce apoptotic cell death, but can also induce autophagy through release of the pro-autophagic BH3 only protein Beclin-1 from Bcl-2. The potential therapeutic effects of (−)-gossypol in chemoresistant bladder cancer and the role of autophagy in this context are hitherto unknown.

Methods

Cisplatin (5637^rCDDP¹⁰⁰⁰, RT4^rCDDP¹⁰⁰⁰) and gemcitabine (5637^rGEMCI²⁰, RT4^rGEMCI²⁰) chemoresistant sub-lines of the chemo-sensitive bladder cancer cell lines 5637 and RT4 were established for the investigation of acquired resistance mechanisms. Cell lines carrying a stable lentiviral knockdown of the core autophagy regulator ATG5 were created from chemosensitive 5637 and chemoresistant 5637^rGEMCI²⁰ and 5637^rCDDP¹⁰⁰⁰ cell lines. Cell death and autophagy were quantified by FACS analysis of propidium iodide, Annexin and Lysotracker staining, as well as LC3 translocation.

Results

Here we demonstrate that (−)-gossypol induces an apoptotic type of cell death in 5637 and RT4 cells which is partially inhibited by the pan-caspase inhibitor z-VAD. Cisplatin- and gemcitabine-resistant bladder cancer cells exhibit enhanced basal and drug-induced autophagosome formation and lysosomal activity which is accompanied by an attenuated apoptotic cell death after treatment with both (−)-gossypol and ABT-737, a Bcl-2 inhibitor which spares Mcl-1, in comparison to parental cells. Knockdown of ATG5 and inhibition of autophagy by 3-MA had no discernible effect on apoptotic cell death induced by (−)-gossypol and ABT-737 in parental 5637 cells, but evoked a significant increase in early apoptosis and overall cell death in BH3 mimetic-treated 5637^rGEMCI²⁰ and 5637^rCDDP¹⁰⁰⁰ cells.

Conclusions

Our findings show for the first time that (−)-gossypol concomitantly triggers apoptosis and a cytoprotective type of autophagy in bladder cancer and support the notion that enhanced autophagy may underlie the chemoresistant phenotype of these tumors. Simultaneous targeting of Bcl-2 proteins and the autophagy pathway may be an efficient new strategy to overcome their “autophagy addiction” and acquired resistance to current therapy.

Expression, activation, and role of AKT isoforms in the uterus

The three isoforms of AKT: AKT1, AKT2, and AKT3, are crucial regulators of both normal and pathological cellular processes. Each of these isoforms exhibits a high level of homology and functional redundancy with each other. However, while being highly similar and structurally homologous, a rising amount of evidence is showing that each isoform possesses specific targets as well as preferential subcellular localization. The role of AKT has been studied extensively in reproductive processes, but isoform-specific roles are yet to be fully understood. This review will focus on the role of AKT in the uterus and its function in processes related to cell death and proliferation such as embryo implantation, decidualization, endometriosis, and endometrial cancer in an isoform-centric manner. In this review, we will cover the activation of AKT in various settings, localization of isoforms in subcellular compartments, and the effect of isoform expression on cellular processes. To fully understand the dynamic molecular processes taking place in the uterus, it is crucial that we better understand the physiological role of AKT isoforms as well as their function in the emergence of diseases.

Polymeric micelles for pH-responsive delivery of cisplatin

Methoxy poly(ethylene oxide)-block-poly-(α-carboxylate-ε-caprolactone) (PEO-b-PCCL) was used to develop pH-responsive polymeric micelles for the delivery of cisplatin (CDDP). Micelles were prepared through complexation of CDDP with the pendant carboxyl groups on the poly(ε-caprolactone) core, perhaps through coordinate bonding. The obtained micelles were characterized using dynamic light scattering (DLS) measurement for size and stability. The in vitro release of CDDP at different pHs (7.4, 6.0 and 5.0) was evaluated. The in vitro cell uptake as well as cytotoxicity of developed micelles against two breast cancer cell lines, i.e. MDA-MB-435 and MDA-MB-231, were also assessed and compared to free CDDP as control. DLS results showed PEO-b-PCCL to form stable micelles with an average diameter of <50 nm upon complexation with CDDP. Developed polymeric micelles were capable of slowly releasing CDDP in physiological pH. However, CDDP release from polymeric micelles was triggered upon exposure to electrolytes and/or acidic pHs mimicking that of extracellular tumor microenvironment or intracellular organelles. Consistent with the slow release of CDDP from its polymeric micellar formulation, polymeric micellar CDDP exhibited lower cytotoxicity and CDDP intracellular uptake compared to free drug. The results indicate a great potential for the developed formulation in platinum therapy of breast cancer.

Chemoresistance to concanamycin A1 in human oral squamous cell carcinoma is attenuated by an HDAC inhibitor partly via suppression of Bcl-2 expression

V-ATPase is involved in the acidification of the microenvironment around/in solid tumors, such as oral squamous cell carcinoma (OSCC). V-ATPase is thought to induce tumor invasion and multi-drug resistance in several malignant tumors, and it also contributes to maintaining the intracellular pH under an acidic microenvironment by inducing proton extrusion into the extracellular medium. However, there is little information regarding the effects of V-ATPase inhibitors on OSCCs. In this study, the effects of a V-ATPase inhibitor, concanamycin A1 (CMA), on the proliferation and apoptosis of OSCC were investigated in vitro. We used four OSCC cell lines, MISK81-5, SAS, HSC-4 and SQUU-B. Acridine orange staining revealed that the red fluorescence was reduced in all of the low concentration CMA-treated OSCC cells, indicating that the acidification of vesicular organelles in the OSCCs was prevented by the treatment with low-concentration of CMA. CMA treatment induced apoptosis in MISK81-5, SAS and HSC-4 cells, but not in SQUU-B cells. The p-p38 expression was not altered in CMA-treated SQUU-B cells, but their levels were increased in the other cells. The Bax/Bcl-2 ratio in CMA-treated SQUU-B cells was dramatically decreased in comparison with that in the other cell lines treated with CMA. However, when the SQUU-B cells were treated with CMA and a histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), the SQUU-B cells became more susceptible to the CMA-induced apoptosis. SAHA treatment led to a significantly decrease in the Bcl-2 expression in CMA-treated SQUU-B cells, resulting in a dramatically increased Bax/Bcl-2 ratio in comparison with that observed in the SQUU-B cells treated with CMA alone. These findings suggest that CMA could have an anti-tumor effect on OSCCs. In addition, combination of CMA with other agents, such as SAHA, could help improve the pro-apoptotic effects of CMA even in CMA-resistant OSCC cells.

Resistance to cisplatin-induced cell death conferred by the activity of organic anion transporting polypeptides (OATP) in human melanoma cells

Expression of organic anion transporting polypeptides (OATP) transporters can be modified with potential incidence in cancers, yet they have not been considered in melanoma. Here, we demonstrate transcriptional and protein expression of OATP members in human melanoma cell lines with sodium-independent organic anion uptake activity. Importantly, uptake of different organic anions over 24 h led to a common resistance signal to apoptotic cell death, induced further by cisplatin in 24 h. The mechanism is not dependent on the transport of cisplatin by the OATP, as it is not an OATP substrate. The resistance signal was modulated by PKC, disclosing it as signal mediator. This study suggests that OATP, which can be constantly activated by endobiotics, may contribute to melanoma chemotherapeutic resistance, thereby justifying the development of OATP targeting strategies.

CD40 pathway activation reveals dual function for macrophages in human endometrial cancer cell survival and invasion

Reproductive malignancies are a major cause of cancer death in women worldwide. CD40 is a TNF receptor family member, which upon activation may mediate tumor regression. However, despite the great potential of CD40 agonists, their use as a therapeutic option for reproductive cancers has never been investigated. Because CD40 ligation is a potent pathway of macrophage activation, an in vitro model of pro-inflammatory type-1 (Mϕ-1) and anti-inflammatory type-2 (Mϕ-2) macrophages was developed to determine whether and how macrophage CD40 pathway activation might influence endometrial tumor cell behavior. Analysis of tumor growth kinetic in the endometrial cancer xenograft model indicates that, when injected once into the growing tumors, CD40-activated Mϕ-1 greatly reduced, while CD40-activated Mϕ-2 increased tumor size when compared to control isotype-activated Mϕ-1 and Mϕ-2, respectively. In vitro assays indicated that CD40-activated Mϕ-2 increased cell viability but failed to promote cell invasion. CD40-activated Mϕ-1, in contrast, decreased cell survival but greatly increased cell invasion in tumor cells less susceptible to cell death by apoptosis; they also induced the expression of some pro-inflammatory genes, such as IL-6, LIF, and TNF-α, known to be involved in tumor promotion and metastasis. The presence of IFN-γ is minimally required for CD40-activated Mϕ-1 to promote tumor cell invasion, a process that is mediated in part through the activation of the PI3K/Akt2 signaling pathway in tumor cells. From these results, we speculate that some functions of CD40 in tumor-associated Mϕs might limit the therapeutic development of CD40 agonists in endometrial cancer malignancies.

Involvement of Akt isoforms in chemoresistance of endometrial carcinoma cells

OBJECTIVE

In tumors, upstream regulation of Akt is affected by oncogenic events which lead to its constitutive activation and promote cell survival. Since studies have demonstrated that the three Akt isoforms exhibit different physiological functions, Akt isoforms may contribute differently in chemoresistance. The objective of the study was to determine the role of each Akt isoforms in chemoresistance.

METHODS

We stably transfected the chemoresistant KLE endometrial carcinoma cells with specific shRNAs for Akt1, Akt2 or Akt3. Alternatively, we stably transfected the chemosensitive Hec-1-A endometrial carcinoma cells, in which no Akt activity is detected, with constitutively active Akt expression vectors for each isoform.

RESULTS

We demonstrated that Akt1 and Akt2 downregulation by RNAi highly sensitizes KLE cells to cisplatin by inducing the activation of pro-apoptotic factors such as the cleavage of caspases-3, -6, -9 and PARP; downregulation of all Akt isoforms leads to increased sensitivity to doxorubicin while only Akt1-2 downregulation increases taxol sensitivity. Proliferation of Akt1, and mostly Akt2 deficient cells was affected by cisplatin treatment. Constitutive Akt1 or Akt2 expression led to an increased resistance to apoptosis. Akt isoforms have been shown to influence migration in other cancer cells. We showed that Akt2 blocks cell motility, while Akt1-3 had less effect on our endometrial cancer cell models.

CONCLUSION

Our findings highlight the contribution of Akt1 and Akt2 in the molecular mechanisms that govern chemoresistance of endometrial carcinomas. Furthermore, Akt isoform-specific transfectants will provide a strong model to determine the involvement of each Akt isoform in tumor progression and metastasis.

Aqueous Extract of Solanum nigrum Leaf Activates Autophagic Cell Death and Enhances Docetaxel-Induced Cytotoxicity in Human Endometrial Carcinoma Cells

Chemotherapy is the main approach in dealing with advanced and recurrent endometrial cancer. An effective complementary ingredient can be helpful in improving the clinical outcome. Aqueous extract of Solanum nigrum leaf (AE-SN) is a principal ingredient for treating cancer patients in traditional Chinese medicinal practice but lacks sufficient evidence to verify its tumor suppression efficacy. This study evaluated the antitumor effects of AE-SN and also assessed the synergistic effects of AE-SN with docetaxel On the human endometrial cancer cell lines, HEC1A, HEC1B, and KLE. The activation of apoptotic markers, caspase-3 and poly-ADP-ribose polymerase, and autophagic marker, microtubule-associated protein 1 light chain 3 A/B, wAS determined to clarify the cell death pathways responsible for AE-SN induced tumor cell death. Results indicated that AE-SN-treatment has significant cytotoxicity on the tested endometrial cancer cells with accumulation of LC3 A/B II and demonstrated a synergistic effect of AE-SN and docetaxel in HEC1A and HEC1B cells, but not KLE cells. In conclusion, AE-SN treatment was effective in suppressing endometrial cancer cells via the autophagic pathway and was also capable of enhancing the cytotoxicity of docetaxel in human endometrial cancer cells. Our results provide meaningful evidence for integrative cancer therapy in the future.