In vitro analysis of ovarian cancer response to cisplatin, carboplatin, and paclitaxel identifies common pathways that are also associated with overall patient survival

Novel frontiers in urogenital cancers: from molecular bases to preclinical models to tailor personalized treatments in ovarian and prostate cancer patients

Over the last few decades, the incidence of urogenital cancers has exhibited diverse trends influenced by screening programs and geographical variations. Among women, there has been a consistent or even increased occurrence of endometrial and ovarian cancers; conversely, prostate cancer remains one of the most diagnosed malignancies, with a rise in reported cases, partly due to enhanced and improved screening efforts.Simultaneously, the landscape of cancer therapeutics has undergone a remarkable evolution, encompassing the introduction of targeted therapies and significant advancements in traditional chemotherapy. Modern targeted treatments aim to selectively address the molecular aberrations driving cancer, minimizing adverse effects on normal cells. However, traditional chemotherapy retains its crucial role, offering a broad-spectrum approach that, despite its wider range of side effects, remains indispensable in the treatment of various cancers, often working synergistically with targeted therapies to enhance overall efficacy.For urogenital cancers, especially ovarian and prostate cancers, DNA damage response inhibitors, such as PARP inhibitors, have emerged as promising therapeutic avenues. In BRCA-mutated ovarian cancer, PARP inhibitors like olaparib and niraparib have demonstrated efficacy, leading to their approval for specific indications. Similarly, patients with DNA damage response mutations have shown sensitivity to these agents in prostate cancer, heralding a new frontier in disease management. Furthermore, the progression of ovarian and prostate cancer is intricately linked to hormonal regulation. Ovarian cancer development has also been associated with prolonged exposure to estrogen, while testosterone and its metabolite dihydrotestosterone, can fuel the growth of prostate cancer cells. Thus, understanding the interplay between hormones, DNA damage and repair mechanisms can hold promise for exploring novel targeted therapies for ovarian and prostate tumors.In addition, it is of primary importance the use of preclinical models that mirror as close as possible the biological and genetic features of patients' tumors in order to effectively translate novel therapeutic findings "from the bench to the bedside".In summary, the complex landscape of urogenital cancers underscores the need for innovative approaches. Targeted therapy tailored to DNA repair mechanisms and hormone regulation might offer promising avenues for improving the management and outcomes for patients affected by ovarian and prostate cancers.

Insights into molecular mechanisms of chemotherapy resistance in cancer

Cancer heterogeneity poses a significant hurdle to the successful treatment of the disease, and is being influenced by genetic inheritance, cellular and tissue biology, disease development, and response to therapy. While chemotherapeutic drugs have demonstrated effectiveness, their efficacy is impeded by challenges such as presence of resilient cancer stem cells, absence of specific biomarkers, and development of drug resistance. Often chemotherapy leads to a myriad of epigenetic, transcriptional and post-transcriptional alterations in gene expression as well as changes in protein expression, thereby leading to massive metabolic reprogramming. This review seeks to provide a detailed account of various transcriptional regulations, proteomic changes, and metabolic reprogramming in various cancer models in response to three primary chemotherapeutic interventions, docetaxel, carboplatin, and doxorubicin. Discussing the molecular targets of some of these regulatory events and highlighting their contribution in sensitivity to chemotherapy will provide insights into drug resistance mechanisms and uncover novel perspectives in cancer treatment.

Toxic Effects of Gemcitabine and Paclitaxel Combination: Chemotherapy Drugs Exposure in Zebrafish

Pharmaceuticals are widely recognized as potentially hazardous to aquatic ecosystems. In the last two decades, the constant intake of biologically active chemicals used in human healthcare has been related to the growing release of these agents into natural environments. As reported by several studies, various pharmaceuticals have been detected, mainly in surface water (seas, lakes, and rivers), but also in groundwater and drinking water. Moreover, these contaminants and their metabolites can show biological activity even at very low concentrations. This study aimed to evaluate the developmental toxicity of exposure to the chemotherapy drugs gemcitabine and paclitaxel in aquatic environments. Zebrafish (Danio rerio) embryos were exposed to doses of gemcitabine 15 μM in combination with paclitaxel 1 μM from 0 to 96 h post-fertilization (hpf) using a fish embryo toxicity test (FET). This study highlights that both gemcitabine and paclitaxel exposure at single non-toxic concentrations affected survival and hatching rate, morphology score, and body length after exposure in combination. Additionally, exposure significantly disturbed the antioxidant defense system and increased ROS in zebrafish larvae. Gemcitabine and paclitaxel exposure caused changes in the expression of inflammation-related, endoplasmic reticulum stress-related (ERS), and autophagy-related genes. Taken together, our findings underline that gemcitabine and paclitaxel increase developmental toxicity in zebrafish embryos in a time-dependent manner.

Paklitakselin neden olduğu oksidatif hasara karşı farnesenin otoprotektif etkileri

Amaç: Bu çalışmanın amacı, güçlü serbest radikal süpürücü ve antioksidan özelliklere sahip farnesenin paklitaksel kaynaklı ototoksisite üzerindeki etkilerini biyokimyasal ve fonksiyonel yönden araştırmaktır. Gereç ve Yöntem: On sekiz erkek Wistar albino sıçan, altı sıçandan oluşan üç gruba rastgele ayrıldı. Araştırma boyunca kontrol grubuna paklitaksel veya farnesen verilmedi. Paklitaksel grubuna, 5mg/kg paklitaksel intraperitoneal olarak dört kez (1., 7., 14. ve 21. günlerde) verildi. Farnesen + paklitaksel grubuna, önce 5 mg/kg paklitaksel, 30 dakika sonra 50 mg/kg farnesen intraperitoneal olarak 4 kez (1., 7., 14. ve 21. günlerde) verildi. 0. ve 21. günlerde tüm sıçanların otoakustik emisyon ölçümü yapıldı. Daha sonra hayvanlar sakrifiye edildi ve biyokimyasal testler için kokleaları çıkarıldı. Bulgular: Paklitaksel, önemli ölçüde malondialdehit seviyelerini yükselterek ve glutatyon seviyelerini düşürerek kokleada oksidatif strese neden oldu. Ayrıca paklitaksel grubunun distorsiyon ürünü otoakustik emisyon değerleri diğer gruplara göre anlamlı derecede düşüktü. Farnesen+paklitaksel grubunda ise paklitakselin çeşitli biyokimyasal ve fonksiyonel parametrelerde oluşturduğu hasarda iyileşmeler gözlendi. Sonuç: Çalışma sonuçları doğal bir antioksidan olan farnesen’in sıçanlarda paklitaksel kaynaklı işitme kaybını azalttığını, farnesen ve paklitaksel kombinasyonunun gelecekte klinik kullanım için paklitaksel kaynaklı ototoksisiteden koruyabileceğini göstermektedir.

The chemotherapeutic drug carboplatin affects macrophage responses to LPS and LPS tolerance via epigenetic modifications

Following re-exposure to lipopolysaccharide (LPS), macrophages exhibit an immunosuppressive state known as LPS tolerance, which is characterized by repressed proinflammatory cytokine production. LPS-induced tolerance in macrophages is mediated in part by epigenetic changes. Carboplatin, an anticancer chemotherapeutic drug, exerts its effect by inhibiting DNA replication and transcription, as well as through epigenetic modifications. Through an unbiased screen, we found that carboplatin rescued TNF-α and IL-6 production in LPS-tolerant macrophages. Transcriptomic analysis and gene set enrichment analyses revealed that p53 was one of the most significantly upregulated hallmarks in both LPS-primed and LPS-tolerant macrophages in the presence of carboplatin, while E2F and G2/M were the most negatively regulated hallmarks. Heterochromatin protein 1 (HP1-α), which is associated with gene silencing, was significantly reduced in carboplatin-treated LPS-tolerant macrophages at the mRNA and protein levels. Dynamic changes in the mRNA level of genes encoding H3K9me3 methyltransferases, setdb2, kdm4d, and suv39h1 were induced in the presence of carboplatin in LPS-tolerant macrophages. Taken together, we provide evidence that carboplatin treatment interferes with proinflammatory cytokine production during the acute LPS response and LPS tolerance in macrophages, possibly via H3K9me3 modification.

Cancer Patient Tissueoid with Self-Homing Nano-Targeting of Metabolic Inhibitor

The current paradigm of cancer medicine focuses on patient- and/or cancer-specific treatments, which has led to continuous progress in the development of patient representatives (e.g., organoids) and cancer-targeting carriers for drug screening. As breakthrough concepts, i) living cancer tissues convey intact profiles of patient-specific microenvironmental signatures. ii) The growth mechanisms of cancer mass with intense cell-cell interactions can be harnessed to develop self-homing nano-targeting by using cancer cell-derived nanovesicles (CaNVs). Hence, a tissueoid model of ovarian cancer (OC) is developed by culturing OC patient tissues in a 3D gel chip, whose microchannel networks enable perfusion to maintain tissue viability. A novel model of systemic cancer responses is approached by xenografting OC tissueoids into ischaemic hindlimbs in nude mice. CaNVs are produced to carry general chemotherapeutics or new drugs under pre/clinical studies that target the BRCA mutation or energy metabolism, thereby increasing the test scope. This pioneer study cross-validates drug responses from the OC clinic, tissueoid, and animal model by demonstrating the alignment of results in drug type-specific efficiency, BRCA mutation-dependent drug efficiency, and metabolism inhibition-based anti-cancer effects. Hence, this study provides a directional foundation to accelerate the discovery of patient-specific drugs with CaNV application towards future precision medicine.

Microtubule Destabilizing Sulfonamides as an Alternative to Taxane-Based Chemotherapy

Pan-Gyn cancers entail 1 in 5 cancer cases worldwide, breast cancer being the most commonly diagnosed and responsible for most cancer deaths in women. The high incidence and mortality of these malignancies, together with the handicaps of taxanes-first-line treatments-turn the development of alternative therapeutics into an urgency. Taxanes exhibit low water solubility that require formulations that involve side effects. These drugs are often associated with dose-limiting toxicities and with the appearance of multi-drug resistance (MDR). Here, we propose targeting tubulin with compounds directed to the colchicine site, as their smaller size offer pharmacokinetic advantages and make them less prone to MDR efflux. We have prepared 52 new Microtubule Destabilizing Sulfonamides (MDS) that mostly avoid MDR-mediated resistance and with improved aqueous solubility. The most potent compounds, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methylaminobenzenesulfonamide 38, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 42, and N-benzyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 45 show nanomolar antiproliferative potencies against ovarian, breast, and cervix carcinoma cells, similar or even better than paclitaxel. Compounds behave as tubulin-binding agents, causing an evident disruption of the microtubule network, in vitro Tubulin Polymerization Inhibition (TPI), and mitotic catastrophe followed by apoptosis. Our results suggest that these novel MDS may be promising alternatives to taxane-based chemotherapy in chemoresistant Pan-Gyn cancers.

Frizzled-7 Identifies Platinum-Tolerant Ovarian Cancer Cells Susceptible to Ferroptosis

Defining traits of platinum-tolerant cancer cells could expose new treatment vulnerabilities. Here, new markers associated with platinum-tolerant cells and tumors were identified using in vitro and in vivo ovarian cancer models treated repetitively with carboplatin and validated in human specimens. Platinum-tolerant cells and tumors were enriched in ALDH+ cells, formed more spheroids, and expressed increased levels of stemness-related transcription factors compared with parental cells. Additionally, platinum-tolerant cells and tumors exhibited expression of the Wnt receptor Frizzled-7 (FZD7). Knockdown of FZD7 improved sensitivity to platinum, decreased spheroid formation, and delayed tumor initiation. The molecular signature distinguishing FZD7+ from FZD7- cells included epithelial-to-mesenchymal (EMT), stemness, and oxidative phosphorylation-enriched gene sets. Overexpression of FZD7 activated the oncogenic factor Tp63, driving upregulation of glutathione metabolism pathways, including glutathione peroxidase 4 (GPX4), which protected cells from chemotherapy-induced oxidative stress. FZD7+ platinum-tolerant ovarian cancer cells were more sensitive and underwent ferroptosis after treatment with GPX4 inhibitors. FZD7, Tp63, and glutathione metabolism gene sets were strongly correlated in the ovarian cancer Tumor Cancer Genome Atlas (TCGA) database and in residual human ovarian cancer specimens after chemotherapy. These results support the existence of a platinum-tolerant cell population with partial cancer stem cell features, characterized by FZD7 expression and dependent on the FZD7-β-catenin-Tp63-GPX4 pathway for survival. The findings reveal a novel therapeutic vulnerability of platinum-tolerant cancer cells and provide new insight into a potential "persister cancer cell" phenotype. SIGNIFICANCE: Frizzled-7 marks platinum-tolerant cancer cells harboring stemness features and altered glutathione metabolism that depend on GPX4 for survival and are highly susceptible to ferroptosis.

The effects of size and shape of the ovarian cancer spheroids on the drug resistance and migration

BACKGROUND

High fatality in ovarian cancer is attributed to metastasis, propagated by the release of multi-cellular aggregates/spheroids into the peritoneal cavity and their subsequent mesothelial invasion of peritoneal organs. Spheroids are therefore a common and clinically relevant in vitro model for ovarian cancer research. Spheroids in patients vary significantly in size and shape and display enhanced resistance to anti-cancer drugs compared to monolayers. However, there is no consensus on how spheroid size and shape affect drug resistance. Moreover, existing data regarding the influence of epithelial-to-mesenchymal transition (EMT) profile on spheroid shape and migration is inconclusive.

METHODS

We formed spheroids with OVCAR-3 and OVCAR-8 cells, chosen for their established genetic similarity to the patient tumor samples. We monitored their morphology using confocal microscope with dipping objective and fluorescent microscope. We characterized important EMT biomarkers; E-cadherin, Vimentin and Slug through western blotting in monolayers and spheroids. We treated these spheroids with Taxol and Cisplatin and investigated their migratory profile based on their morphology.

RESULTS

We report two distinct multicellular structures: loose aggregates (OVCAR-3) and compact spheroids (OVCAR-8). We attribute these different morphologies to the expression of the EMT biomarkers, and their changes upon spheroid formation. Importantly, we did not observe a difference in resistance to the anti-cancer drugs as a function of spheroid size and shape. However, migration capacity of compact spheroid (OVCAR-8) was 15-fold higher compared to that of loose aggregates (OVCAR-3).

CONCLUSIONS

These results highlight the importance of spheroid size and shape on anti-cancer drug resistance and migration profiles. The results of this study can, therefore, help to elucidate general rules for ovarian cancer studies based on 3D samples.

A CREB1/miR-433 reciprocal feedback loop modulates proliferation and metastasis in colorectal cancer

Increasing evidence has indicated the prognostic value of miR-433 across a series of malignancy types. However, the underlying mechanisms involved in cancer progression haven’t been sufficiently elucidated. In the present work, we found that miR-433 was downregulated in CRC tissues and cell lines. Ectopic expression of miR-433 obviously suppressed the proliferation, invasion and metastasis activity of CRC cells in vitro and in vivo. CREB1, CCAR1 and JNK1 were highly expressed and negatively correlated with miR-433 expression in CRC. CRC patients with higher expression of CREB1, CCAR1 or JNK1 presented a worse outcome relative to those with lower expression. CREB1 transactivated the expression of miR-433, and CREB1, CCAR1 and JNK1 simultaneously served as its targets, which in turn composed a feedback loop between CREB1 and miR-433. miR-433 blocked cell cycle progression and abolished EMT. Collectively, our study demonstrated the CREB1/miR-433 reciprocal feedback loop restrained the propagation, invasion and metastasis activities of CRC cells through abrogation of cell cycle progression and constraint of EMT.

Wnt Signaling Protects against Paclitaxel-Induced Spiral Ganglion Neuron Damage in the Mouse Cochlea In Vitro

It has been reported that paclitaxel administration could cause sensorineural hearing loss, and Wnt activation is important for the development and cell protection of mouse cochlea. However, the effect of Wnt signaling in spiral ganglion neurons (SGNs) damage induced by paclitaxel has not yet been elucidated. In this study, we explored the effect of paclitaxel on SGNs in the mouse cochlea and the neuroprotective effects of Wnt signaling pathway against paclitaxel-induced SGN damage by using Wnt agonist/antagonists in vitro. We first found that paclitaxel treatment resulted in a degenerative change and reduction of cell numbers in SGNs and induced caspase-mediated apoptosis in SGNs. The expression levels of β-catenin and C-myc were increased, thus indicating Wnt signaling was activated in SGNs after paclitaxel treatment. The activation of Wnt signaling pathway protected against SGN loss after exposure to paclitaxel, whereas the suppression of Wnt signaling in SGNs made them more vulnerable to paclitaxel treatment. We also showed that activation of Wnt signaling in SGNs inhibited caspase-mediated apoptosis. Our findings demonstrated that Wnt signaling had an important role in protecting SGNs against paclitaxel-induced damage and thus might be an effective therapeutic target for the prevention of paclitaxel-induced SGN death.

pathCHEMO, a generalizable computational framework uncovers molecular pathways of chemoresistance in lung adenocarcinoma

Despite recent advances in discovering a wide array of novel chemotherapy agents, identification of patients with poor and favorable chemotherapy response prior to treatment administration remains a major challenge in clinical oncology. To tackle this challenge, we present a generalizable genome-wide computational framework pathCHEMO that uncovers interplay between transcriptomic and epigenomic mechanisms altered in biological pathways that govern chemotherapy response in cancer patients. Our approach is tested on patients with lung adenocarcinoma who received adjuvant standard-of-care doublet chemotherapy (i.e., carboplatin-paclitaxel), identifying seven molecular pathway markers of primary treatment response and demonstrating their ability to predict patients at risk of carboplatin-paclitaxel resistance in an independent patient cohort (log-rank p-value = 0.008, HR = 10). Furthermore, we extend our method to additional chemotherapy-regimens and cancer types to demonstrate its accuracy and generalizability. We propose that our model can be utilized to prioritize patients for specific chemotherapy-regimens as a part of treatment planning.

Nusrat Epsi et al. present pathCHEMO, a computational framework for uncovering transcriptomic and epigenomic pathways of chemoresistance in cancer that has the potential to improve clinical decision-making. They apply pathCHEMO to lung adenocarcinoma data from public databases, and identify seven molecular pathways implicated in carboplatin-paclitaxel resistance.

p53-Bad: A Novel Tumor Suppressor/Proapoptotic Factor Hybrid Directed to the Mitochondria for Ovarian Cancer Gene Therapy

Clinical trials involving p53 gene therapy for ovarian cancer failed due to the dominant negative inhibition of wild-type p53 and multiple genetic aberrations in ovarian cancer. To overcome this problem, we have designed a more potent chimeric gene fusion, called p53-Bad, that combines p53 with the mitochondrial pro-apoptotic factor Bad. Unlike wild-type p53, which acts as a nuclear transcription factor, this novel p53-Bad construct has multiple unique mechanisms of action including a direct and rapid apoptotic effect at the mitochondria. The mitochondrial localization, transcription activity, and apoptotic activity of the constructs were tested. The results suggest that p53 can be effectively targeted to the mitochondria by controlling the phosphorylation of pro-apoptotic Bad, which can only localize to the mitochondria when Ser-112 and Ser-136 of Bad are unphosphorylated. By introducing S112A and S136A mutations, p53-Bad fusion cannot be phosphorylated at these two sites and always localizes to the mitochondria. p53-Bad constructs also have superior activity over p53 and Bad alone. The apoptotic activity is consistent in many ovarian cancer cell lines regardless of the endogenous p53 status. Both p53 and the BH3 domain of Bad contribute to the superior activity of p53-Bad. Our data suggests that p53-Bad fusions are capable of inducing apoptosis and should be further pursued for gene therapy for ovarian cancer.

Mitochondrially targeted p53 or DBD subdomain is superior to wild type p53 in ovarian cancer cells even with strong dominant negative mutant p53

Background

While tumor suppressor p53 functions primarily as a transcription factor in the nucleus, cellular stress can cause p53 to translocate to the mitochondria and directly trigger a rapid apoptotic response. We have previously shown that fusing p53 (or its DNA binding domain, DBD, alone) to the mitochondrial targeting signal (MTS) from Bak or Bax can target p53 to the mitochondria and induce apoptosis in gynecological cancer cell lines including cervical cancer cells (HeLa; wt p53), ovarian cancer cells (SKOV-3; p53 267del non-expressing), and breast cancer cells (T47D; L194F p53 mutation). However, p53 with Bak or Bax MTSs have not been previously tested in cancers with strong dominant negative (DN) mutant p53 which are capable of inactivating wt p53 by homo-oligomerization. Since p53-Bak or Bax MTS constructs act as monomers, they are not subject to DN inhibition. For this study, the utility of p53-Bak or p53-Bax MTS constructs was tested for ovarian cancers which are known to have varying p53 statuses, including a strong DN contact mutant p53 (Ovcar-3 cells), a p53 DN structural mutant (Kuramochi cells), and a p53 wild type, low expressing cells (ID8).

Results

Our mitochondrial p53 constructs were tested for their ability to localize to the mitochondria in both mutant non-expressing p53 (Skov-3) and p53 structural mutant (Kuramochi) cell lines using fluorescence microscopy and a nuclear transcriptional activity assay. The apoptotic activity of these mitochondrial constructs was determined using a mitochondrial outer membrane depolarization assay (TMRE), caspase assay, and a late stage cell death assay (7-AAD). We also tested the possibility of using our constructs with paclitaxel, the current standard of care in ovarian cancer treatment. Our data indicates that our mitochondrial p53 constructs are able to effectively localize to the mitochondria in cancer cells with structural mutant p53 and induce apoptosis in many ovarian cancer cell lines with different p53 statuses. These constructs can also be used in combination with paclitaxel for an increased apoptotic effect.

Conclusions

The results suggest that targeting p53 to mitochondria can be a new strategy for ovarian cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s13048-019-0516-2) contains supplementary material, which is available to authorized users.

Biological Insights into Chemotherapy Resistance in Ovarian Cancer

The majority of patients with high-grade serous ovarian cancer (HGSOC) initially respond to chemotherapy; however, most will develop chemotherapy resistance. Gene signatures may change with the development of chemotherapy resistance in this population, which is important as it may lead to tailored therapies. The objective of this study was to compare tumor gene expression profiles in patients before and after treatment with neoadjuvant chemotherapy (NACT). Tumor samples were collected from six patients diagnosed with HGSOC before and after administration of NACT. RNA extraction and whole transcriptome sequencing was performed. Differential gene expression, hierarchical clustering, gene set enrichment analysis, and pathway analysis were examined in all of the samples. Tumor samples clustered based on exposure to chemotherapy as opposed to patient source. Pre-NACT samples were enriched for multiple pathways involving cell cycle growth. Post-NACT samples were enriched for drug transport and peroxisome pathways. Molecular subtypes based on the pre-NACT sample (differentiated, mesenchymal, proliferative and immunoreactive) changed in four patients after administration of NACT. Multiple changes in tumor gene expression profiles after exposure to NACT were identified from this pilot study and warrant further attention as they may indicate early changes in the development of chemotherapy resistance.

Effect of c-Met and CD44v6 Expression in Resistance to Chemotherapy in Esophageal Squamous Cell Carcinoma

BACKGROUND

c-Met relies on CD44v6 for its activation and signaling in several cancer cell lines. However, the correlation of c-Met and CD44v6 expression and its biological significance in esophageal squamous cell carcinoma (ESCC) remains unknown.

METHODS

Expression of c-Met and CD44v6 was examined by immunohistochemistry (IHC) in 147 ESCC specimens. We analyzed the impact of c-Met and CD44v6 expression on clinicopathological parameters, including chemoresistance or prognosis in ESCC.

RESULTS

High expression of c-Met and CD44v6 in cancerous lesions was identified in 49.7% and 50.3% of all patients, respectively. The c-Met-high group comprised more advanced pT and pM stages than the c-Met-low group. In addition, more patients in the c-Met-high group received neoadjuvant chemotherapy (NACT) than the c-Met-low group (64.4% vs. 43.2%, P = 0.010). On the other hand, the CD44v6-high group was associated with more advanced pT/pN stages and a poorer clinical response to NACT (response rate 53.5% vs. 77.8%, P = 0.025) than the CD44v6-low group. Double-positive immunostaining of c-Met and CD44v6 was identified in 28.6% of all cases, and multivariate analysis of overall survival (OS) identified them (hazard ratio 1.79, 95% confidence interval 1.03-3.04, P = 0.038) as independent prognostic factors in addition to pN and pM stage.

CONCLUSIONS

c-Met/CD44v6 were associated with tumor progression or chemoresistance. Double-positive expression of c-Met and CD44v6 negatively impacted patient prognosis in ESCC, implying that c-Met and CD44v6 are candidates for targeted therapy in ESCC.

Roflumilast enhances cisplatin-sensitivity and reverses cisplatin-resistance of ovarian cancer cells via cAMP/PKA/CREB-FtMt signalling axis

OBJECTIVE

We previously demonstrated the roflumilast inhibited cell proliferation and increased cell apoptosis in ovarian cancer. In this study, we aimed to investigate the roles of roflumilast in development of cisplatin (DDP)-sensitive and -resistant ovarian cancer.

METHODS

OVCAR3 and SKOV3 were selected and the corresponding DDP-resistant cells were constructed. Cell viability, proliferation, apoptosis, cycle were performed. Expression cAMP, PKA, CREB, phosphorylation of CREB and FtMt were detected. The roles of roflumilast in development of DDP-sensitive and -resistant ovarian cancer were confirmed by xenograft model.

RESULTS

Roflumilast + DDP inhibited cell proliferation, and induced cell apoptosis and G0/G1 arrest in OVCAR3 and SKOV3 cells, roflumilast induced expression of FtMt, the activity of cAMP and PKA and phosphorylation of CREB in ovarian cancer cells and the above-effect were inhibited by H89. Downregulation of CREB inhibited the roflumilast-increased DDP sensitivity of ovarian cancer cells, and the roflumilast-induced FtMt expression and phosphorylation of CREB. Also, roflumilast reversed cisplatin-resistance, and induced expression of FtMt and activation of cAMP/PKA/CREB in DDP-resistant ovarian cancer cells. Similarly, treated with H89 or downregulation of CREB inhibited the changes induced by roflumilast. In vivo, roflumilast inhibited the development of SKOV3 or SKOV3-DDP-R xenograft models.

CONCLUSIONS

Roflumilast enhanced DDP sensitivity and reversed the DDP resistance of ovarian cancer cells via activation of cAMP/PKA/CREB pathway and upregulation of the downstream FtMt expression, which has great promise in clinical treatment.

Cisplatin triggers cancer stem cell enrichment in platinum-resistant cells through NF-κB-TNFα-PIK3CA loop

Background

Parallel to complex alteration in molecular and cellular events, enrichment of cancer stem cells (CSC) contributes significantly in deliberation and maintenance of cisplatin resistance. Cisplatin mediated CSC enrichment is well established in various cancers, yet the underlying mechanism is largely unknown. Cisplatin also promotes transcriptional upregulation of PIK3CA, hence activating PI3K/AKT signaling in resistant cells. However, such cisplatin-induced transcriptional regulators of PIK3CA and their impact on cancer stem cell population in resistant cells are largely unknown.

Methods

DNA-binding protein pulldown using PIK3CA promoter as bait followed by nLCMS was used to identify, cisplatin-induced potential transcriptional regulators of PIK3CA promoter. PIK3CA promoter activity was estimated by luciferase based reporter assay. ChIP was used to assess interaction of NF-κB with PIK3CA promoter. CSC-enriched side-population was sorted using DCV-dye exclusion methods. All the gene expression levels were assessed using qPCR.

Results

Using a transcription factor pull-down assay with PIK3CA promoter, we identified NF-κB as a prime regulator, which escalates both TNFα and PIK3CA expression only in CSC enriched side-population (SP) but not in non side-population (NSP) in platinum resistant ovarian cancer cells upon cisplatin treatment. This SP-specific NF-κB-TNFα-PIK3CA bi-modal loop, on one hand, maintains persistent activation of NF-κB through TNFα- NF-κB autocrine loop, while NF-κB-PIK3CA loop nurture CSC population under cisplatin treatment. Activation of PI3K/AKT signalling drives SP’s into an undifferentiated, anti-apoptotic stage through upregulating P21, P27,cFLIP expression. Contrarily, lack of active NF-κB-TNFα-PIK3CA loop makes NSPs vulnerable towards cisplatin and undergoes apoptosis. Altogether, cisplatin enriches cancer stem cells properties in SP fraction, which is evident from increased levels of pluripotency gene OCT4/SOX2/NANOG expression. Disruption of PIK3CA-NF-κB loop by Wortamannin reduces SP fraction by 1.4–1.6 fold in control and treated cells.

Conclusion

Together, our study signifies an active role of NF-κB-TNFα-PIK3CA bi-modal loop in cisplatin-mediated promotion and maintenance of CSC-like population in platinum-resistant cells.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0636-8) contains supplementary material, which is available to authorized users.

Identification of epithelial ovarian tumor-specific aptamers

Ovarian cancer is often diagnosed in late stages with few treatment options and poor long-term prognosis. New clinical tools for early detection of ovarian malignancies will significantly help reduce mortality and improve current long-term survival rates. The objective of this work was to identify ovarian tumor-specific single-stranded DNA aptamers that bind to malignant ovarian tumor cells and internalize with high affinity and specificity. Aptamers can identify unique tumor biomarkers, can aid in early detection and diagnosis of neoplastic disorders, and can be functionalized by conjugation to small molecules. To identify aptamers from random single-stranded DNA pools (60 bases long), we used whole Cell-SELEX (systematic evolution of ligands by exponential enrichment) to enrich and isolate tumor-specific aptamers that bind to tumor-specific receptors in their native state on the cell surface. Next-Generation sequencing identified seven novel aptamers and detailed analyses of three are described. Aptamers bound to, and were internalized by, target Caov-3 cell populations, but not nontarget nonmalignant ovarian epithelial HOSE 6-3 cells or multiple other epithelial tumor cell lines. Furthermore, aptamers showed unique binding affinities with apparent dissociation constants (Kd) measuring in the submicromolar range supporting their physiological relevance and potential use in clinical applications.

Interference with the expression of β-catenin reverses cisplatin resistance in A2780/DDP cells and inhibits the progression of ovarian cancer in mouse model

Cisplatin is a most active drug for the treatment of ovarian cancer; however, acquired cisplatin resistance is easily seen in patients with ovarian cancer. The aim of this study is to clarify the molecular mechanism of cisplatin resistance and try to reverse cisplatin resistance in ovarian cancer lines in vitro and in vivo. First, we used ovarian cancer cell line A2780, and its cisplatin-resistant subline, A2780/DDP as cell model. Cell viability was determined by MTT assay and the IC50 values were observed to increase in a dose- and time-dependent manner. Next, the expression of β-catenin was determined by western blotting analysis, and the results demonstrated that the expression level of β-catenin in A2780/DDP cells was significantly higher than that in A2780 cells (p<0.01). Moreover, we detected the distribution of cytoplasmic and nuclear β-catenin by western blot analysis, which showed that β-catenin was mainly located in nucleus. Compared with A2780 cells, there was no obvious change as the increasing dose of cisplatin in A2780/DDP cells reveal that cisplatin resistance was related to the exrpession of β-catenin. Furthermore, interference with the expression of β-catenin could effectively reverse cisplatin resistance as IC50 was significantly decreased from 123.7 to 42.43 μM in A2780/DDP cells. Additionally, transient interference of β-catenin by siRNA promoted the apoptosis of A2780/DDP cells, for increased apoptosis rates and cleaved caspase-3 levels were detected being treated with cisplatin. Finally, tumorigenicity experiments showed that tumor growth was significantly suppressed in β-catenin shRNA group. The body weight was not significantly changed during the experimental days. In conclusion, all the results showed that cisplatin resistance was partly induced by Wnt/β-catenin signaling pathway. Interfering the expression of β-catenin could reverse cisplatin resistance in vitro and in vivo. Thus, β-catenin could be a potential therapeutic target for the therapy of cisplatin-resistant ovarian cancer.

Label-free LC-MSe in tissue and serum reveals protein networks underlying differences between benign and malignant serous ovarian tumors

Purpose

To identify proteins and (molecular/biological) pathways associated with differences between benign and malignant epithelial ovarian tumors.

Experimental Procedures

Serum of six patients with a serous adenocarcinoma of the ovary was collected before treatment, with a control group consisting of six matched patients with a serous cystadenoma. In addition to the serum, homogeneous regions of cells exhibiting uniform histology were isolated from benign and cancerous tissue by laser microdissection. We subsequently employed label-free liquid chromatography tandem mass spectrometry (LC-MS^e) to identify proteins in these serum and tissues samples. Analyses of differential expression between samples were performed using Bioconductor packages and in-house scripts in the statistical software package R. Hierarchical clustering and pathway enrichment analyses were performed, as well as network enrichment and interactome analysis using MetaCore.

Results

In total, we identified 20 and 71 proteins that were significantly differentially expressed between benign and malignant serum and tissue samples, respectively. The differentially expressed protein sets in serum and tissue largely differed with only 2 proteins in common. MetaCore network analysis, however inferred GCR-alpha and Sp1 as common transcriptional regulators. Interactome analysis highlighted 14-3-3 zeta/delta, 14-3-3 beta/alpha, Alpha-actinin 4, HSP60, and PCBP1 as critical proteins in the tumor proteome signature based on their relative overconnectivity. The data have been deposited to the ProteomeXchange with identifier PXD001084.

Discussion

Our analysis identified proteins with both novel and previously known associations to ovarian cancer biology. Despite the small overlap between differentially expressed protein sets in serum and tissue, APOA1 and Serotransferrin were significantly lower expressed in both serum and cancer tissue samples, suggesting a tissue-derived effect in serum. Pathway and subsequent interactome analysis also highlighted common regulators in serum and tissue samples, suggesting a yet unknown role for PCBP1 in ovarian cancer pathophysiology.

MAVTgsa: an R package for gene set (enrichment) analysis

Gene set analysis methods aim to determine whether an a priori defined set of genes shows statistically significant difference in expression on either categorical or continuous outcomes. Although many methods for gene set analysis have been proposed, a systematic analysis tool for identification of different types of gene set significance modules has not been developed previously. This work presents an R package, called MAVTgsa, which includes three different methods for integrated gene set enrichment analysis. (1) The one-sided OLS (ordinary least squares) test detects coordinated changes of genes in gene set in one direction, either up- or downregulation. (2) The two-sided MANOVA (multivariate analysis variance) detects changes both up- and downregulation for studying two or more experimental conditions. (3) A random forests-based procedure is to identify gene sets that can accurately predict samples from different experimental conditions or are associated with the continuous phenotypes. MAVTgsa computes the P values and FDR (false discovery rate) q-value for all gene sets in the study. Furthermore, MAVTgsa provides several visualization outputs to support and interpret the enrichment results. This package is available online.

Analysis of chemotherapeutic response in ovarian cancers using publicly available high-throughput data

A third of patients with epithelial ovarian cancer (OVCA) will not respond to standard treatment. The determination of a robust signature that predicts chemoresponse could lead to the identification of molecular markers for response as well as possible clinical implementation in the future to identify patients at risk of failing therapy. This pilot study was designed to identify biologic processes affecting candidate pathways associated with chemoresponse and to create a robust gene signature for follow-up studies. After identifying common pathways associated with chemoresponse in serous OVCA in three independent gene-expression experiments, we assessed the biologic processes associated with them using The Cancer Genome Atlas (TCGA) dataset for serous OVCA. We identified differential copy-number alterations (CNA), mutations, DNA methylation, and miRNA expression between patients that responded to standard treatment and those who did not or recurred prematurely. We correlated these significant parameters with gene expression to create a signature of 422 genes associated with chemoresponse. A consensus clustering of this signature identified two differentiated clusters with unique molecular patterns: cluster 1 was significant for cellular signaling and immune response (mainly cell-mediated); and cluster 2 was significant for pathways involving DNA-damage repair and replication, cell cycle, and apoptosis. Validation through consensus clustering was performed in five independent OVCA gene-expression experiments. Genes were located in the same cluster with consistent agreement in all five studies (κ coefficient ≥ 0.6 in 4). Integrating high-throughput biologic data have created a robust molecular signature that predicts chemoresponse in OVCA.

Platinum compounds for high-resolution in vivo cancer imaging

Platinum(II) compounds, principally cisplatin and carboplatin, are commonly used front-line cancer therapeutics. Despite their widespread use and continued interest in the development of new derivatives, including nanoformulations with improved properties, it has been difficult to visualize platinum compounds in live subjects, in real time, and with subcellular resolution. Here, we present four novel cisplatin- and carboplatin-derived fluorescent imaging compounds for quantitative intravital cancer imaging. We conjugated 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-daiza-s-indacene (BODIPY) to Pt(II) complexes to generate derivatives with robust in vivo fluorescence and retained DNA-damaging and cytotoxic properties. We successfully applied these compounds to image pharmacokinetics and tumor uptake in a xenograft cancer mouse model. By using a genetic reporter of single-cell DNA damage for in vivo imaging, Pt drug accumulation and resultant DNA damage could be monitored in individual tumor cells, at subcellular resolution, and in real time in a live animal model of cancer. These derivatives represent promising imaging tools that will be useful in understanding further the distribution and interactions of platinum within tumors.

Identification of reproducible gene expression signatures in lung adenocarcinoma

BACKGROUND

Lung cancer is the leading cause of cancer-related death worldwide. Tremendous research efforts have been devoted to improving treatment procedures, but the average five-year overall survival rates are still less than 20%. Many biomarkers have been identified for predicting survival; challenges arise, however, in translating the findings into clinical practice due to their inconsistency and irreproducibility. In this study, we proposed an approach by identifying predictive genes through pathways.

RESULTS

The microarrays from Shedden et al. were used as the training set, and the log-rank test was performed to select potential signature genes. We focused on 24 cancer-related pathways from 4 biological databases. A scoring scheme was developed by the Cox hazard regression model, and patients were divided into two groups based on the medians. Subsequently, their predictability and generalizability were evaluated by the 2-fold cross-validation and a resampling test in 4 independent datasets, respectively. A set of 16 genes related to apoptosis execution was demonstrated to have good predictability as well as generalizability in more than 700 lung adenocarcinoma patients and was reproducible in 4 independent datasets. This signature set was shown to have superior performances compared to 6 other published signatures. Furthermore, the corresponding risk scores derived from the set were found to associate with the efficacy of the anti-cancer drug ZD-6474 targeting EGFR.

CONCLUSIONS

In summary, we presented a new approach to identify reproducible survival predictors for lung adenocarcinoma, and the identified genes may serve as both prognostic and predictive biomarkers in the future.

A novel c-Met inhibitor, MK8033, synergizes with carboplatin plus paclitaxel to inhibit ovarian cancer cell growth

Elevated serum levels of hepatocyte growth factor (HGF) and high tumor expression of c-Met are both indicators of poor overall survival from ovarian cancer (OVCA). In the present study, we evaluated the role of the HGF signaling pathway in OVCA cell line chemoresistance and OVCA patient overall survival as well as the influence of HGF/c-Met signaling inhibition on the sensitivity of OVCA cells to combinational carboplatin plus paclitaxel therapy. The prevalence of the HGF receptor, c-Met, was determined by immunohistochemistry in primary OVCA samples (n=79) and OVCA cell lines (n=41). The influence of the c-Met-specific inhibitor MK8033 on OVCA cell sensitivity to combinations of carboplatin plus paclitaxel was examined in a subset of OVCA cells (n=8) by CellTiter-Blue cell viability assays. Correlation tests were used to identify genes associated with response to MK8033 and carboplatin plus paclitaxel. Identified genes were evaluated for influence on overall survival from OVCA using principal component analysis (PCA) modeling in an independent clinical OVCA dataset (n=218). Immunohistochemistry analysis indicated that 83% of OVCA cells and 92% of primary OVCA expressed the HGF receptor, c-Met. MK8033 exhibited significant anti-proliferative effects against a panel of human OVCA cell lines. Combination index values determined by the Chou-Talalay isobologram equation indicated synergistic activity in combinations of MK8033 and carboplatin plus paclitaxel. Pearson's correlation identified a 47-gene signature to be associated with MK8033-carboplatin plus paclitaxel response. PCA modeling indicated an association of this 47-gene response signature with overall survival from OVCA (P=0.013). These data indicate that HGF/c-Met pathway signaling may influence OVCA chemosensitivity and overall patient survival. Furthermore, HGF/c-Met inhibition by MK8033 represents a promising new therapeutic avenue to increase OVCA sensitivity to carboplatin plus paclitaxel.