Cancer cell adaptation to chemotherapy

LINC01138 expresses two novel isoforms and functions as a repressive factor in glioma cells

Objective

The objective of this study is to investigate the aggressive infiltration of glioblastoma into adjacent brain tissue, considering its challenging prognosis. Initially classified as an intergenic non-coding RNA, we aim to elucidate the functional implications of LINC01138 in glioblastoma.

Method

Glioma grading was performed utilizing H&E staining, which unveiled distinct nuclear morphology in high-grade gliomas. The downregulation of LINC01138 in glioma tissues was corroborated through qRT-PCR and gel electrophoresis, concurrently identifying two previously unrecognized LINC01138 isoforms. Expression profiling of all four LINC01138 isoforms was executed in glioma cell lines (A172, SHG-44, U251, U87-MG). The impact of LINC01138 overexpression in U87-MG and U251 cells was evaluated for cell proliferation, migration, and invasion through cell counting, CCK-8 analysis, and Transwell assays. Furthermore, the suppression of LINC01138 in SHG-44 cells substantiated its involvement in fostering tumor malignancy. Transcriptome sequencing revealed the inhibitory influence of LINC01138 on IGF1 expression. These findings contribute to an enriched comprehension of glioma biology by exploring the engagement of LINC01138 through diverse methodologies, thereby elucidating its potential therapeutic significance.

Results

Our investigation elucidates the intricate involvement of LINC01138 in gliomas. High-grade gliomas are characterized by elevated cell density and distinctive nuclear features. LINC01138 demonstrates a substantial downregulation in glioma tissues, with the identification of two novel isoforms. The expression of all four LINC01138 isoforms is notably diminished in both glioma tissues and cell lines. Elevated expression of LINC01138 demonstrates inhibitory effects on tumor cell proliferation, migration, and invasion, while its downregulation exacerbates malignancy. The regulatory function of LINC01138 as a repressor of IGF1 expression was elucidated through transcriptome sequencing.

Conclusion

The LINC01138 isoforms display notable tumor-suppressive effects, suggesting a promising potential for impeding glioma progression.

The Role of Cytokines in Activation of Tumour-promoting Pathways and Emergence of Cancer Drug Resistance

Scientists are constantly researching and launching potential chemotherapeutic agents as an irreplaceable weapon to fight the battle against cancer. Despite remarkable advancement over the past several decades to wipe out cancer through early diagnosis, proper prevention, and timely treatment, cancer is not ready to give up and leave the battleground. It continuously tries to find some other way to give a tough fight for its survival, either by escaping from the effect of chemotherapeutic drugs or utilising its own chemical messengers like cytokines to ensure resistance. Cytokines play a significant role in cancer cell growth and progression, and the present article highlights their substantial contribution to mechanisms of resistance toward therapeutic drugs. Multiple clinical studies have even described the importance of specific cytokines released from cancer cells as well as stromal cells in conferring resistance. Herein, we discuss the different mechanism behind drug resistance and the crosstalk between tumor development and cytokines release and their contribution to showing resistance towards chemotherapeutics. As a part of this review, different approaches to cytokines profile have been identified and employed to successfully target new evolving mechanisms of resistance and their possible treatment options.

Hybridization of the Pharmacophoric Features of Discoipyrrole C and Combretastatin A-4 toward New Anticancer Leads

Pharmacophore hybridization is an attractive strategy to identify new leads against multifactorial diseases such as cancer. Based on literature analysis of compounds possessing 'vicinal diaryl' fragment in their structure, we considered Discoipyrroles A-D and Combretastatin A-4 (CA-4) as possible components in hybrid design. Discoipyrrole C (Dis C) and CA-4 were used as reference compounds in these studies and their hybrids, in the form of 4,5-diaryl-1H-pyrrol-3(2H)-ones, were synthesized from suitable amino acid precursors though their ynone intermediates. Of these, the hybrid having exact substitution pattern as that of CA-4 showed better potency and selectivity than Dis C, but its activity was less compared to CA-4. This new analog disrupted interphase microtubules by inhibiting tubulin assembly by binding to the colchicine site, induced multipolar spindles, caused cell cycle block and apoptosis in HeLa cells. It also inhibited colony formation and migration of breast cancer cell lines.

Exposure to Neoadjuvant Oxaliplatin-Containing Chemotherapy, Does it Effect Intraperitoneal Hyperthermic Chemotherapy Perfusion?

INTRODUCTION

Patients undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) are commonly exposed to oxaliplatin neoadjuvant chemotherapy (NAT) regimens. The impact of systemic exposure to oxaliplatin prior to HIPEC with oxaliplatin is unknown.

METHODS

We conducted a retrospective review of our institutional registry of CRS/HIPEC cases who received oxaliplatin-containing NAT, and compared patients who underwent HIPEC with oxaliplatin versus cases perfused with mitomycin C. The primary outcome was survival, defined by overall survival (OS) and disease-free survival (DFS). Subgroup analysis was performed based on primary tumor etiology and completeness of cytoreduction.

RESULTS

A total of 333 cases satisfied the selection criteria-159 appendiceal primaries (all high-grade disease) and 174 colorectal cases. Thirty-one cases (9.3%) underwent HIPEC with oxaliplatin, with the remaining 302 cases (90.7%) receiving mitomycin C. Both cohorts were identical in regard to baseline characteristics, and both groups were alike in regard to NAT regimens and oxaliplatin exposure. There was no difference in survival outcomes. OS times were 2.9 (± 2.8) and 2.8 ( ± 3.6) years for oxaliplatin and mitomycin C perfusions, respectively (p = 0.94), and the 5-year OS rates were also similar at 9.7 and 18.5% (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.14-1.67, p = 0.24) for oxaliplatin and mitomycin cases, respectively. Likewise, DFS findings were similar, with survival of 2.5 (± 4.5) and 1.8 (± 2.4) years for oxaliplatin and mitomycin perfusions, respectively (p = 0.21). There was no difference in 5-year DFS rates, at 10.5 and 7.8% (OR 1.39, 95% CI 0.30-6.56, p = 0.68) for oxaliplatin and mitomycin C, respectively. Subgroup analysis found minimal discordant findings from the main results.

CONCLUSION

This analysis found no discernable association with NAT oxaliplatin exposure in regard to survival outcomes following CRS/HIPEC stratified out by perfusion agent.

Switching Perfusion Agents for Repeat Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy: Surgical Dogma or Evidence-Based Practice?

BACKGROUND

A common practice is to switch chemotherapy perfusion agents for repeat cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). However, there is a paucity of objective benefit with this practice.

METHODS

A retrospective review of our institutional registry involving repeat CRS-HIPEC cases was conducted, comparing cases that underwent a perfusion agent switch versus those cases with no switch. The primary outcome of this study was survival, measured by overall survival (OS) and disease-free survival (DFS). A subgroup analysis was performed on the basis of primary etiology.

RESULTS

A total of 101 cases met selection criteria. Mitomycin C was used as the index perfusion agent in 84% of cases, while oxaliplatin was utilized in the remaining 16% of cases. In total, 66 cases underwent a perfusion switch, with 35 cases using the same agent. Analysis revealed no survival benefit with HIPEC perfusion switch. For OS, there were similar mean survival times of 5.2 (± 4.1) years and 5.1 (± 3.6) years for cases with perfusion switch and no perfusion switch, respectively (P = 0.985). The 5-year OS rates were also similar at 61.4% and 53.3% for switch and non-switch cases, respectively [odds ratio (OR) 0.41, 95% confidence interval (CI) 0.54-3.56, P = 0.49]. Mean DFS was 4.0 (± 4.2) years and 3.6 (± 3.8) years for switch and non-switch cases, respectively (P = 0.74). The 5-year DFS rates had a greater difference with statistical trend, with rates of 53% versus 28% for switch and non-switch cases, respectively (OR 2.91, 95% CI 0.86-9.86, P = 0.081). Subgroup analysis had a similar trend to the main results.

CONCLUSIONS

The study findings revealed no survival benefit with switching perfusion agents. Analysis suggests that the practice of perfusion switch is ineffective.

Pitavastatin and Ivermectin Enhance the Efficacy of Paclitaxel in Chemoresistant High-Grade Serous Carcinoma

Simple Summary

The main challenge in high-grade serous carcinoma management is to unveil therapeutic approaches to overcome chemoresistance. Drug combinations and repurposing of non-oncological agents are attractive strategies that allow for higher efficacy, decreased toxicity, and the overcoming of chemoresistance. Several non-oncological drugs display an effective anti-cancer activity and have been studied to be repurposed in multi-drug resistant neoplasms. The purpose of our study was to explore whether combining Paclitaxel with repurposed drugs (Pitavastatin, Metformin, Ivermectin, Itraconazole and Alendronate) led to a therapeutic benefit. Our results showed that the combination of Paclitaxel with Pitavastatin or Ivermectin demonstrates the highest cytotoxic effect and the strongest synergism among all combinations for two chemoresistant cell lines. Thus, the combination of these repurposed drugs with Paclitaxel could be a particularly valuable strategy to treat ovarian cancer patients with intrinsic or acquired chemoresistance.

Abstract

Chemotherapy is a hallmark in high-grade serous carcinoma management; however, chemoresistance and side effects lead to therapeutic interruption. Combining repurposed drugs with chemotherapy has the potential to improve antineoplastic efficacy, since drugs can have independent mechanisms of action and suppress different pathways simultaneously. This study aimed to explore whether the combination of Paclitaxel with repurposed drugs led to a therapeutic benefit. Thus, we evaluated the cytotoxic effects of Paclitaxel alone and in combination with several repurposed drugs (Pitavastatin, Metformin, Ivermectin, Itraconazole and Alendronate) in two tumor chemoresistant (OVCAR8 and OVCAR8 PTX R P) and a non-tumoral (HOSE6.3) cell lines. Cellular viability was assessed using Presto Blue assay, and the synergistic interactions were evaluated using Chou–Talalay, Bliss Independence and Highest Single Agent reference models. The combination of Paclitaxel with Pitavastatin or Ivermectin showed the highest cytotoxic effect and the strongest synergism among all combinations for both chemoresistant cell lines, resulting in a chemotherapeutic effect superior to both drugs alone. Almost all the repurposed drugs in combination with Paclitaxel presented a safe pharmacological profile in non-tumoral cells. Overall, we suggest that Pitavastatin and Ivermectin could act synergistically in combination with Paclitaxel, being promising two-drug combinations for high-grade serous carcinoma management.

Regulation of NKG2D Stress Ligands and Its Relevance in Cancer Progression

Under cellular distress, multiple facets of normal homeostatic signaling are altered or disrupted. In the context of the immune landscape, external and internal stressors normally promote the expression of natural killer group 2 member D (NKG2D) ligands that allow for the targeted recognition and killing of cells by NKG2D receptor-bearing effector populations. The presence or absence of NKG2D ligands can heavily influence disease progression and impact the accessibility of immunotherapy options. In cancer, tumor cells are known to have distinct regulatory mechanisms for NKG2D ligands that are directly associated with tumor progression and maintenance. Therefore, understanding the regulation of NKG2D ligands in cancer will allow for targeted therapeutic endeavors aimed at exploiting the stress response pathway. In this review, we summarize the current understanding of regulatory mechanisms controlling the induction and repression of NKG2D ligands in cancer. Additionally, we highlight current therapeutic endeavors targeting NKG2D ligand expression and offer our perspective on considerations to further enhance the field of NKG2D ligand biology.

Nanomedicine Strategies for Management of Drug Resistance in Lung Cancer

Lung cancer (LC) is one of the leading causes of cancer occurrence and mortality worldwide. Treatment of patients with advanced and metastatic LC presents a significant challenge, as malignant cells use different mechanisms to resist chemotherapy. Drug resistance (DR) is a complex process that occurs due to a variety of genetic and acquired factors. Identifying the mechanisms underlying DR in LC patients and possible therapeutic alternatives for more efficient therapy is a central goal of LC research. Advances in nanotechnology resulted in the development of targeted and multifunctional nanoscale drug constructs. The possible modulation of the components of nanomedicine, their surface functionalization, and the encapsulation of various active therapeutics provide promising tools to bypass crucial biological barriers. These attributes enhance the delivery of multiple therapeutic agents directly to the tumor microenvironment (TME), resulting in reversal of LC resistance to anticancer treatment. This review provides a broad framework for understanding the different molecular mechanisms of DR in lung cancer, presents novel nanomedicine therapeutics aimed at improving the efficacy of treatment of various forms of resistant LC; outlines current challenges in using nanotechnology for reversing DR; and discusses the future directions for the clinical application of nanomedicine in the management of LC resistance.

Stress Responses as Master Keys to Epigenomic Changes in Transcriptome and Metabolome for Cancer Etiology and Therapeutics

From initiation through progression, cancer cells are subjected to a magnitude of endogenous and exogenous stresses, which aid in their neoplastic transformation. Exposure to these classes of stress induces imbalance in cellular homeostasis and, in response, cancer cells employ informative adaptive mechanisms to rebalance biochemical processes that facilitate survival and maintain their existence. Different kinds of stress stimuli trigger epigenetic alterations in cancer cells, which leads to changes in their transcriptome and metabolome, ultimately resulting in suppression of growth inhibition or induction of apoptosis. Whether cancer cells show a protective response to stress or succumb to cell death depends on the type of stress and duration of exposure. A thorough understanding of epigenetic and molecular architecture of cancer cell stress response pathways can unveil a plethora of information required to develop novel anticancer therapeutics. The present view highlights current knowledge about alterations in epigenome and transcriptome of cancer cells as a consequence of exposure to different physicochemical stressful stimuli such as reactive oxygen species (ROS), hypoxia, radiation, hyperthermia, genotoxic agents, and nutrient deprivation. Currently, an anticancer treatment scenario involving the imposition of stress to target cancer cells is gaining traction to augment or even replace conventional therapeutic regimens. Therefore, a comprehensive understanding of stress response pathways is crucial for devising and implementing novel therapeutic strategies.

Tissue Type Differences in ABCB1 Expression and Paclitaxel Tissue Pharmacokinetics in Patients With Esophageal Cancer

Background: Data from previous work suggests that there is no correlation between systemic (plasma) paclitaxel exposure and efficacy in patients treated for esophageal cancer. In this trial, we investigated ATP-binding cassette efflux transporter expression and intratumoral pharmacokinetics of paclitaxel to identify changes which could be a first sign of chemoresistance.

Methods: Patients with esophageal cancer treated with paclitaxel and carboplatin (± concomitant radiotherapy) were included. During the first and last cycle of weekly paclitaxel, blood samples and biopsies of esophageal mucosa and tumor tissue were taken. Changes in paclitaxel exposure and expression of ABCB1 (P-glycoprotein) over time were studied in both tumor tissue and normal appearing esophageal mucosa.

Results: ABCB1 was significantly higher expressed in tumor tissue compared to esophageal tissue, during both the first and last cycle of paclitaxel (cycle 1: p < 0.01; cycle 5/6: p = 0.01). Interestingly, ABCB1 expression was significantly higher in adenocarcinoma than in squamous cell carcinoma (p < 0.01). During the first cycle, a trend towards a higher intratumoral paclitaxel concentration was observed compared to the esophageal mucosa concentration (RD:43%; 95%CI: −3% to 111% p = 0.07). Intratumoral and plasma paclitaxel concentrations were significantly correlated during the first cycle (AUC_0–48 h: r = 0.72; p < 0.01).

Conclusion: Higher ABCB1 expression in tumor tissue, and differences between histological tumor types might partly explain why tumors respond differently to systemic treatment. Resistance by altered intratumoral paclitaxel concentrations could not be demonstrated because the majority of the biopsies taken at the last cycle of paclitaxel did contain a low amount of tumor cells or no tumor.

Anticancer drug resistance: An update and perspective

Driver mutations promote initiation and progression of cancer. Pharmacological treatment can inhibit the action of the mutant protein; however, drug resistance almost invariably emerges. Multiple studies revealed that cancer drug resistance is based upon a plethora of distinct mechanisms. Drug resistance mutations can occur in the same protein or in different proteins; as well as in the same pathway or in parallel pathways, bypassing the intercepted signaling. The dilemma that the clinical oncologist is facing is that not all the genomic alterations as well as alterations in the tumor microenvironment that facilitate cancer cell proliferation are known, and neither are the alterations that are likely to promote metastasis. For example, the common KRasG12C driver mutation emerges in different cancers. Most occur in NSCLC, but some occur, albeit to a lower extent, in colorectal cancer and pancreatic ductal carcinoma. The responses to KRasG12C inhibitors are variable and fall into three categories, (i) new point mutations in KRas, or multiple copies of KRAS G12C which lead to higher expression level of the mutant protein; (ii) mutations in genes other than KRAS; (iii) original cancer transitioning to other cancer(s). Resistance to adagrasib, an experimental antitumor agent exerting its cytotoxic effect as a covalent inhibitor of the G12C KRas, indicated that half of the cases present multiple KRas mutations as well as allele amplification. Redundant or parallel pathways included MET amplification; emerging driver mutations in NRAS, BRAF, MAP2K1, and RET; gene fusion events in ALK, RET, BRAF, RAF1, and FGFR3; and loss-of-function mutations in NF1 and PTEN tumor suppressors. In the current review we discuss the molecular mechanisms underlying drug resistance while focusing on those emerging to common targeted cancer drivers. We also address questions of why cancers with a common driver mutation are unlikely to evolve a common drug resistance mechanism, and whether one can predict the likely mechanisms that the tumor cell may develop. These vastly important and tantalizing questions in drug discovery, and broadly in precision medicine, are the focus of our present review. We end with our perspective, which calls for target combinations to be selected and prioritized with the help of the emerging massive compute power which enables artificial intelligence, and the increased gathering of data to overcome its insatiable needs.

Role of the bone marrow microenvironment in drug resistance of hematological malignances

The unique features of the tumor microenvironment (TME) govern the biological properties of many cancers, including hematological malignancies. TME factors can trigger invasion, and protect against drug cytotoxicity by inhibiting apoptosis and activating specific signaling pathways (e.g. NF-ΚB). TME remodeling is facilitated due to the high self-renewal ability of the bone marrow. Progressing tumor cells can alter some extracellular matrix (ECM) components which act as a barrier to drug penetration in the TME. The initial progression of the cell cycle is controlled by the MAPK pathway (Raf/MEK/ERK) and Hippo pathway, while the final phase is regulated by the PI3K/Akt /mTOR and WNT pathways. In this review we summarize the main signaling pathways involved in drug resistance (DR) and some mechanisms by which DR can occur in the bone marrow. The relationship between autophagy, endoplasmic reticulum stress, and cellular signaling pathways in DR and apoptosis are covered in relation to the TME.

Sequential Administration of XPO1 and ATR Inhibitors Enhances Therapeutic Response in TP53-mutated Colorectal Cancer

BACKGROUND & AIMS

Understanding the mechanisms by which tumors adapt to therapy is critical for developing effective combination therapeutic approaches to improve clinical outcomes for patients with cancer.

METHODS

To identify promising and clinically actionable targets for managing colorectal cancer (CRC), we conducted a patient-centered functional genomics platform that includes approximately 200 genes and paired this with a high-throughput drug screen that includes 262 compounds in four patient-derived xenografts (PDXs) from patients with CRC.

RESULTS

Both screening methods identified exportin 1 (XPO1) inhibitors as drivers of DNA damage-induced lethality in CRC. Molecular characterization of the cellular response to XPO1 inhibition uncovered an adaptive mechanism that limited the duration of response in TP53-mutated, but not in TP53-wild-type CRC models. Comprehensive proteomic and transcriptomic characterization revealed that the ATM/ATR-CHK1/2 axes were selectively engaged in TP53-mutant CRC cells upon XPO1 inhibitor treatment and that this response was required for adapting to therapy and escaping cell death. Administration of KPT-8602, an XPO1 inhibitor, followed by AZD-6738, an ATR inhibitor, resulted in dramatic antitumor effects and prolonged survival in TP53-mutant models of CRC.

CONCLUSIONS

Our findings anticipate tremendous therapeutic benefit and support the further evaluation of XPO1 inhibitors, especially in combination with DNA damage checkpoint inhibitors, to elicit an enduring clinical response in patients with CRC harboring TP53 mutations.

The Potential Role of Sildenafil in Cancer Management through EPR Augmentation

Enhanced permeation retention (EPR) was a significant milestone discovery by Maeda et al. paving the path for the emerging field of nanomedicine to become a powerful tool in the fight against cancer. Sildenafil is a potent inhibitor of phosphodiesterase 5 (PDE-5) used for the treatment of erectile dysfunction (ED) through the relaxation of smooth muscles and the modulation of vascular endothelial permeability. Overexpression of PDE-5 has been reported in lung, colon, metastatic breast cancers, and bladder squamous carcinoma. Moreover, sildenafil has been reported to increase the sensitivity of tumor cells of different origins to the cytotoxic effect of chemotherapeutic agents with augmented apoptosis mediated through inducing the downregulation of Bcl-xL and FAP-1 expression, enhancing reactive oxygen species (ROS) generation, phosphorylating BAD and Bcl-2, upregulating caspase-3,8,9 activities, and blocking cells at G0/G1 cell cycle phase. Sildenafil has also demonstrated inhibitory effects on the efflux activity of ATP-binding cassette (ABC) transporters such as ABCC4, ABCC5, ABCB1, and ABCG2, ultimately reversing multidrug resistance. Accordingly, there has been a growing interest in using sildenafil as monotherapy or chemoadjuvant in EPR augmentation and management of different types of cancer. In this review, we critically examine the basic molecular mechanism of sildenafil related to cancer biology and discuss the overall potential of sildenafil in enhancing EPR-based anticancer drug delivery, pointing to the outcomes of the most important related preclinical and clinical studies.

Role of ATP-Binding Cassette Transporter Proteins in CNS Tumors: Resistance- Based Perspectives and Clinical Updates

Despite gigantic advances in medical research and development, chemotherapeutic resistance remains a major challenge in complete remission of CNS tumors. The failure of complete eradication of CNS tumors has been correlated with the existence of several factors including overexpression of transporter proteins. To date, 49 ABC-transporter proteins (ABC-TPs) have been reported in humans, and the evidence of their strong association with chemotherapeutics' influx, dissemination, and efflux in CNS tumors, is growing. Research studies on CNS tumors are implicating ABC-TPs as diagnostic, prognostic and therapeutic biomarkers that may be utilised in preclinical and clinical studies. With the current advancements in cell biology, molecular analysis of genomic and transcriptomic interplay, and protein homology-based drug-transporters interaction, our research approaches are streamlining the roles of ABC-TPs in cancer and multidrug resistance. Potential inhibitors of ABC-TP for better clinical outcomes in CNS tumors have emerged. Elacridar has shown to enhance the chemo-sensitivity of Dasatanib and Imatinib in various glioma models. Tariquidar has improved the effectiveness of Temozolomide's in CNS tumors. Although these inhibitors have been effective in preclinical settings, their clinical outcomes have not been as significant in clinical trials. Thus, to have a better understanding of the molecular evaluations of ABC-TPs, as well as drug-interactions, further research is being pursued in research labs. Our lab aims to better comprehend the biological mechanisms involved in drug resistance and to explore novel strategies to increase the clinical effectiveness of anticancer chemotherapeutics, which will ultimately improve clinical outcomes.

Approaching sites of action of drugs in clinical pharmacology: New analytical options and their challenges

Clinical pharmacology is an important discipline for drug development aiming to define pharmacokinetics (PK), pharmacodynamics (PD) and optimum exposure to drugs, i.e. the concentration-response relationship and its modulators. For this purpose, information on drug concentrations at the anatomical, cellular and molecular sites of action is particularly valuable. In pharmacological assays, the limited accessibility of target cells in readily available samples (i.e. blood) often hampers mass spectrometry-based monitoring of the absolute quantity of a compound and the determination of its molecular action at the cellular level. Recently, new sample collection methods have been developed for the specific capture of rare circulating cells, especially for the diagnosis of circulating tumour cells. In parallel, new advances and developments in mass spectrometric instrumentation now allow analyses to be scaled down to the cellular level. Together, these developments may permit the monitoring of minute drug quantities and show their effect at the cellular level. In turn, such PK/PD associations on a cellular level would not only enrich our pharmacological knowledge of a given compound but also expand the basis for PK/PD simulations. In this review, we describe novel concepts supporting clinical pharmacology at the anatomical, cellular and molecular sites of action, and highlight the new challenges in mass spectrometry-based monitoring. Moreover, we present methods to tackle these challenges and define future needs.

Understanding Breast cancer: from conventional therapies to repurposed drugs

Breast cancer is the most common cancer among women and is considered a developed country disease. Moreover, is a heterogenous disease, existing different types and stages of breast cancer development, therefore, better understanding of cancer biology, helps to improve the development of therapies. The conventional treatments accessible after diagnosis, have the main goal of controlling the disease, by improving survival. In more advance stages the aim is to prolong life and symptom palliation care. Surgery, radiation therapy and chemotherapy are the main options available, which must be adapted to each person individually. However, patients are developing resistance to the conventional therapies. This resistance is due to alterations in important regulatory pathways such as PI3K/AKt/mTOR, this pathway contributes to trastuzumab resistance, a reference drug to treat breast cancer. Therefore, is proposed the repurposing of drugs, instead of developing drugs de novo, for example, to seek new medical treatments within the drugs available, to be used in breast cancer treatment. Providing safe and tolerable treatments to patients, and new insights to efficacy and efficiency of breast cancer treatments. The economic and social burden of cancer is enormous so it must be taken measures to relieve this burden and to ensure continued access to therapies to all patients. In this review we focus on how conventional therapies against breast cancer are leading to resistance, by reviewing those mechanisms and discussing the efficacy of repurposed drugs to fight breast cancer.

Oligomeric proanthocyanidins (OPCs) from grape seed extract suppress the activity of ABC transporters in overcoming chemoresistance in colorectal cancer cells

Multidrug resistance is a major hindrance in managing cancer. By performing a series of experiments in chemoresistant colorectal cancer cell lines, we demonstrate that oligomeric proanthocyanidins (OPCs) from grape seed extracts can sensitize both acquired (HCT116-FOr cells) and innately chemoresistant (H716 cells) cancer cells to chemotherapeutic drugs, 5-fluorouracil (5FU) and oxaliplatin, by inhibiting adenosine triphosphate-binding cassette (ABC) transporter proteins. When combined with chemotherapeutic drugs, OPCs significantly inhibited growth of the chemoresistant cells (P < 0.05 to < 0.001) and decreased the expression of several key ABC transporters. Moreover, the activity of the ABC transporters was also significantly decreased by OPCs in the cell lines (P < 0.05). We further confirmed that co-treatment with OPCs sensitized the chemoresistant cells to 5FU and oxaliplatin, as observed by improvement in cell cycle arrest, double-strand breaks and p53 accumulation in these cells. In addition, we confirmed that co-administration of OPCs with chemotherapeutic drugs significantly decreased chemoresistant xenograft tumor growth in mice (P < 0.05). Together, our study illuminates the downregulation of multiple ABC transporters as a mechanism by which OPCs overcome chemoresistance in cancer cells and may serve as adjunctive treatments in patients with refractory colorectal cancer.

Necrosis in the Tumor Microenvironment and Its Role in Cancer Recurrence

Cancer recurrence is one of the most imminent problems in the current world of medicine, and it is responsible for most of the cancer-related death rates worldwide. Long-term administration of anticancer cytotoxic drugs may act as a double-edged sword, as necrosis may lead to renewed cancer progression and treatment resistance. The lack of nutrients, coupled with the induced hypoxia, triggers cell death and secretion of signals that affect the tumor niche. Many efforts have been made to better understand the contribution of hypoxia and metabolic stress to cancer progression and resistance, but mostly with respect to inflammation. Here we provide an overview of the direct anticancer effects of necrotic signals, which are not necessarily mediated by inflammation and the role of DAMPs (damage-associated molecular patterns) on the formation of a pro-cancerous environment.

Bioengineered adipose-derived stem cells for targeted enzyme-prodrug therapy of ovarian cancer intraperitoneal metastasis

The objective of this study was to develop a stem cell-based system for targeted suicide gene therapy of recurrent, metastatic, and unresectable ovarian cancer. Malignant cells were obtained from the ascites of a patient with advanced recurrent epithelial ovarian cancer (named OVASC-1). Cancer cells were characterized to determine the percentages of drug-resistant ALDH+ cells, MDR-1/ABCG2 overexpressing cells, and cancer stem-like cells. The sensitivity and resistance of the OVASC-1 cells and spheroids to the metabolites of three different enzyme/prodrug systems were assessed, and the most effective one was selected. Adipose-derived stem cells (ASCs) were genetically engineered to express recombinant secretory human carboxylesterase-2 and nanoluciferase genes for simultaneous disease therapy and quantitative imaging. Bioluminescent imaging, magnetic resonance imaging and immuno/histochemistry results show that the engineered ASCs actively targeted and localized at both tumor stroma and necrotic regions. This created the unique opportunity to deliver drugs to not only tumor supporting cells in the stroma, but also to cancer stem-like cells in necrotic/hypoxic regions. The statistical analysis of intraperitoneal OVASC-1 tumor burden and survival rates in mice shows that the administration of the bioengineered ASCs in combination with irinotecan prodrug in the designed sequence and timeline eradicated all intraperitoneal tumors and provided survival benefits. In contrast, treatment of the drug-resistant OVASC-1 tumors with cisplatin/paclitaxel (standard-of-care) did not have any statistically significant benefit. The histopathology and hematology results do not show any toxicity to major peritoneal organs. Our toxicity data in combination with efficacy outcomes delineate a nonsurgical and targeted stem cell-based approach to overcoming drug resistance in recurrent metastatic ovarian cancer.

Oncobox Bioinformatical Platform for Selecting Potentially Effective Combinations of Target Cancer Drugs Using High-Throughput Gene Expression Data

Sequential courses of anticancer target therapy lead to selection of drug-resistant cells, which results in continuous decrease of clinical response. Here we present a new approach for predicting effective combinations of target drugs, which act in a synergistic manner. Synergistic combinations of drugs may prevent or postpone acquired resistance, thus increasing treatment efficiency. We cultured human ovarian carcinoma SKOV-3 and neuroblastoma NGP-127 cancer cell lines in the presence of Tyrosine Kinase Inhibitors (Pazopanib, Sorafenib, and Sunitinib) and Rapalogues (Temsirolimus and Everolimus) for four months and obtained cell lines demonstrating increased drug resistance. We investigated gene expression profiles of intact and resistant cells by microarrays and analyzed alterations in 378 cancer-related signaling pathways using the bioinformatical platform Oncobox. This revealed numerous pathways linked with development of drug resistant phenotypes. Our approach is based on targeting proteins involved in as many as possible signaling pathways upregulated in resistant cells. We tested 13 combinations of drugs and/or selective inhibitors predicted by Oncobox and 10 random combinations. Synergy scores for Oncobox predictions were significantly higher than for randomly selected drug combinations. Thus, the proposed approach significantly outperforms random selection of drugs and can be adopted to enhance discovery of new synergistic combinations of anticancer target drugs.

High-Dose Tanshinone IIA Suppresses Migration and Proliferation While Promoting Apoptosis of Astrocytoma Cells Via Notch-1 Pathway

Malignant astrocytoma is the most common malignant tumor with strong invasion in the central nervous system. Tanshinone IIA is an effective compound to suppress cell proliferation and promote cell apoptosis. However, there is little research about the role of tanshinone IIA in the treatment of astrocytoma. This study aimed to investigate the effect of tanshinone IIA on migration, proliferation and apoptosis of astrocytoma cells. The efficacy of tanshinone IIA on migration, proliferation and apoptosis of astrocytoma cells were evaluated by flow cytometry and the assays of plate clone formation, CCK-8, wound healing and transwell migration. The protein molecule and signaling pathway were detected by western blot. High-dose tanshinone IIA suppressed migration and proliferation of astrocytoma cells while promoting apoptosis of astrocytoma cells. The western blot results showed that there were high Notch-1 protein expression and low c-Myc, MMP-9 and Bcl-2 activation in the high-dose tanshinone IIA group compared with the control group. High-dose tanshinone IIA suppresses astrocytoma cell proliferation, migration while promoting apoptosis through Notch-1 pathway. Tanshinone IIA may be used to develop new drugs for the treatment of astrocytoma.

Implementation of genomic medicine for gastrointestinal tumors

Genomic medicine is an approach to take advantage of genomic data in medical practice and health care. The advancement of sequencing technologies has enabled the determination of individual genomes as well as the genome in neoplasms. In the field of human cancer, understanding genomic alterations in tumors and variations associated with drug responses has paved the way towards the development of new drugs and personalized medicine. International collaborations of cancer genome analyses have accumulated a huge body of information about somatic mutations, and identified new driver mutations and pathways in a wide range of cancers. In particular, a growing body of evidence has shown that information about mutations in neoplasms helps to assess the efficacy and resistance of anti-cancer drugs. Information about germline mutations associated with hereditary cancer has been shown to benefit patients by enabling early detection of their tumors and disease-specific treatment, as well as reducing the risk for those at risk. To promote personalized medicine in a more cost-effective and personalized way, further inter-institutional, nationwide, and international collaboration is needed. This article summarizes the background and current situation of genomic medicine in the field of gastrointestinal tumors to help physicians and medical coworkers by assisting their better understanding of genomic medicine and strengthening their confidence of its clinical use.

Platinum sensitivity of ovarian cancer cells does not influence their ability to induce M2-type macrophage polarization

PROBLEM

Development of platinum resistance in ovarian cancer is mediated by both cancer cells and tumor microenvironment. Activation of epithelial-mesenchymal transition program in cancer cells may lead to enrichment for resistant clones. These processes can be affected by tumor-associated macrophages, a highly plastic population of cells that participate in tumor progression and response to treatment by shaping the microenvironment. We aimed to study how platinum resistance influences the crosstalk between macrophages and ovarian cancer cells.

METHOD OF STUDY

Using cisplatin-sensitive ovarian cancer cell line A2780, we developed and characterized cisplatin-resistant A2780Cis and cisplatin and doxorubicin co-resistant A2780Dox cell lines. Next, we set up an indirect coculture system with THP-1 cell line-derived M0-type-, M1-type- and M2-type-like polarized macrophages. We monitored the expression of genes associated with cellular stemness, multidrug resistance, and epithelial-mesenchymal transition in cancer cells, and expression profile of M1/M2 markers in macrophages.

RESULTS

Development of drug resistance in ovarian cancer cell lines was accompanied by increased migration, clonogenicity, and upregulated expression of transcription factors, associated with cellular stemness and epithelial-mesenchymal transition. Upon coculture, we noted that the most relevant changes in gene expression profile occurred in A2780 cells. Moreover, M0- and M1-type macrophages, but not M2-type macrophages, showed significant transcriptional alterations.

CONCLUSION

Our results provide the evidence for bidirectional interplay between cancer cells and macrophages. Independent of platinum resistance status, ovarian cancer cells polarize macrophages toward M2-like type, whereas macrophages induce epithelial-mesenchymal transition and stemness-related gene expression profile in cisplatin-sensitive, but not cisplatin-resistant cancer cells.

Breast cancer complexity: implications of intratumoral heterogeneity in clinical management

Generation of intratumoral phenotypic and genetic heterogeneity has been attributed to clonal evolution and cancer stem cells that together give rise to a tumor with complex ecosystems. Each ecosystem contains various tumor cell subpopulations and stromal entities, which, depending upon their composition, can influence survival, therapy responses, and global growth of the tumor. Despite recent advances in breast cancer management, the disease has not been completely eradicated as tumors recur despite initial response to treatment. In this review, using data from clinically relevant breast cancer models, we show that the fates of tumor stem cells/progenitor cells in the individual tumor ecosystems comprising a tumor are predetermined to follow a limited (unipotent) and/or unlimited (multipotent) path of differentiation which create conditions for active generation and maintenance of heterogeneity. The resultant dynamic systems respond differently to treatments, thus disrupting the delicate stability maintained in the heterogeneous tumor. This raises the question whether it is better then to preserve stability by preventing takeover by otherwise dormant ecosystems in the tumor following therapy. The ultimate strategy for personalized therapy would require serial assessments of the patient's tumor for biomarker validation during the entire course of treatment that is combined with their three-dimensional mapping to the tumor architecture and landscape.

ABC Transporters and Their Role in the Neoadjuvant Treatment of Esophageal Cancer

The prognosis of esophageal cancer (EC) is poor, despite considerable effort of both experimental scientists and clinicians. The tri-modality treatment consisting of neoadjuvant chemoradiation followed by surgery has remained the gold standard over decades, unfortunately, without significant progress in recent years. Suitable prognostic factors indicating which patients will benefit from this tri-modality treatment are missing. Some patients rapidly progress on the neoadjuvant chemoradiotherapy, which is thus useless and sometimes even harmful. At the same time, other patients achieve complete remission on neoadjuvant chemoradiotherapy and subsequent surgery may increase their risk of morbidity and mortality. The prognosis of patients ranges from excellent to extremely poor. Considering these differences, the role of drug metabolizing enzymes and transporters, among other factors, in the EC response to chemotherapy may be more important compared, for example, with pancreatic cancer where all patients progress on chemotherapy regardless of the treatment or disease stage. This review surveys published literature describing the potential role of ATP-binding cassette transporters, the genetic polymorphisms, epigenetic regulations, and phenotypic changes in the prognosis and therapy of EC. The review provides knowledge base for further research of potential predictive biomarkers that will allow the stratification of patients into defined groups for optimal therapeutic outcome.

Carrier-Free Microspheres of an Anti-Cancer Drug Synthesized via a Sodium Catalyst for Controlled-Release Drug Delivery

There are several challenges involved in the development of effective anti-cancer drugs, including accurate drug delivery without toxic side effects. Possible systemic toxicity and the rapid biodegradation of drug carriers are potential risks in the use of carriers for drug-delivery formulations. Therefore, the carrier-free drug delivery of an anti-cancer drug is desirable. Herein, 4-amino-2-benzyl-6-methylpyrimidine (ABMP) was synthesized via a new method using a sodium catalyst, and proved to be effective in inducing breast cancer cell (MDA-MB-231) apoptosis. Moreover, the transparent amorphous state solid of ABMP was demonstrated to have a slow-release property in phosphate buffer solution (PBS). Microspheres of ABMP were prepared with diameters in the range of 5-15 μm. The slow-release property of the ABMP microspheres indicated their potential use for controlled-release drug delivery. We believe that microspheres of ABMP have potential as a new kind of carrier-free anti-cancer drug delivery system.

Thymidylate synthase: a predictive biomarker in resected colorectal liver metastases receiving 5-FU treatment

AIM

To investigate the role of thymidylate synthase (TS) as a predictive biomarker in patients with resected colorectal liver metastases (CRLM).

MATERIALS & METHODS

PubMed, EMBASE and Cochrane Library were queried up to June 2017. Meta-analysis was performed using random-effects model. Risk of bias was assessed using funnel plots.

RESULTS

Six eligible studies were included, comprising a total of 542 patients. Meta-analysis demonstrated a trend to reduced overall survival in patients with resected CRLM with TS overexpression, with a hazard ratio of 1.13 (95% CI: 0.99-1.29; p = 0.08). In three studies where patients received systemic fluorouracil, the pooled hazard ratio was 2.25 (95% CI: 1.37-3.71; p = 0.001).

CONCLUSION

TS appears to be a clinically relevant predictive biomarker in patients with resected CRLM receiving systemic 5-FU.

Omega-3 Fatty Acid Grafted PAMAM-Paclitaxel Conjugate Exhibits Enhanced Anticancer Activity in Upper Gastrointestinal Cancer Cells

Upper Gastrointestinal Cancers (UGCs) are a leading cause of cancer-related deaths worldwide. Paclitaxel (PTX) is frequently used for the treatment of UGCs; however, low bioavailability, reduced solubility, and dose-dependent toxicity impede its therapeutic use. PAMAMG_4.0 -NH₂ -DHA is synthesized by linking amine-terminated fourth-generation poly(amidoamine) (PAMAMG_4.0 -NH₂ ) dendrimers with omega-3 fatty acid docosahexaenoic acid (DHA). Next, PAMAMG_4.0 -NH₂ -DHA-PTX (DHATX) and PAMAMG_4.0 -NH₂ -PTX (PAX) conjugates are synthesized by subsequent covalent binding of PTX with PAMAMG_4.0 -NH₂ -DHA and PAMAMG_4.0 -NH₂ , respectively. ¹ H-NMR and MALDI-TOF analyses are performed to confirm conjugation of DHA to PAMAMG_4.0 -NH₂ and PTX to PAMAMG_4.0 -NH₂ -DHA. The cell viability, clonogenic cell survival, and flow cytometry analyses are used to determine the anticancer activity of PTX, PAX, and DHATX in UGC cell lines. The in vitro data indicate that treatment with DHATX is significantly more potent than PTX or PAX at inhibiting cellular proliferation, suppressing long-term survival, and inducing cell death in UGC cells.

The role of miR-451 in the switching between proliferation and migration in malignant glioma cells: AMPK signaling, mTOR modulation and Rac1 activation required

Glioblastoma multiforme (GBM), WHO grade IV astrocytoma, is the most common primary neoplasm of the central nervous system (CNS) and has the highest malignancy and mortality rates. The invasive nature of GBM complicates surgical resection and restricts chemotherapeutic access, contributing to poor patient prognosis. The migration of tumor cells is closely related to the tumor cell proliferation. The acquisition of migratory capability, in addition to intracellular factors, is proposed to be a crucial mechanism during the progression of invasion. Using qRT-PCR analysis, we determined that the expression of miR-451 in glioma tissue was lower than in control brain tissue, especially in the central portions of the tumor. In glioma cell lines, we found that decreased miR-451 expression suppressed tumor cell proliferation but enhanced migration with a concomitant low level of CAB39/AMPK/mTOR pathway activation and high level of Rac1/cofilin pathway activation, respectively. Notably, the effect of miR-451 on cytological behavior and on the activation of mTOR and Rac1 was limited when AMPKα1 expression was knocked-down with a synthetic shRNA. We suggest that the glioma microenvironment results in heterogeneity of miR-451 expression. Our data indicated that miR-451 relays environmental signals by upregulating the activity of AMPK signaling, thereby modulating the activation of mTOR and Rac1/cofilin which, in turn, play key roles in glioma cell proliferation and migration, respectively. Our results highlight the need to consider opposing roles of a therapeutic target which, while suppressing tumor cell proliferation, could also promote cell infiltration.

Molecular chess? Hallmarks of anti-cancer drug resistance

Background

The development of resistance is a problem shared by both classical chemotherapy and targeted therapy. Patients may respond well at first, but relapse is inevitable for many cancer patients, despite many improvements in drugs and their use over the last 40 years.

Review

Resistance to anti-cancer drugs can be acquired by several mechanisms within neoplastic cells, defined as (1) alteration of drug targets, (2) expression of drug pumps, (3) expression of detoxification mechanisms, (4) reduced susceptibility to apoptosis, (5) increased ability to repair DNA damage, and (6) altered proliferation. It is clear, however, that changes in stroma and tumour microenvironment, and local immunity can also contribute to the development of resistance. Cancer cells can and do use several of these mechanisms at one time, and there is considerable heterogeneity between tumours, necessitating an individualised approach to cancer treatment. As tumours are heterogeneous, positive selection of a drug-resistant population could help drive resistance, although acquired resistance cannot simply be viewed as overgrowth of a resistant cancer cell population. The development of such resistance mechanisms can be predicted from pre-existing genomic and proteomic profiles, and there are increasingly sophisticated methods to measure and then tackle these mechanisms in patients.

Conclusion

The oncologist is now required to be at least one step ahead of the cancer, a process that can be likened to ‘molecular chess’. Thus, as well as an increasing role for predictive biomarkers to clinically stratify patients, it is becoming clear that personalised strategies are required to obtain best results.

Molecular and Pharmacological Mechanisms of Drug Resistance:An Evolving Paradigm

The high heterogeneity and genomic instability of malignant tumors explains why even responsive tumors contain cell clones that are resistant for many possible mechanisms involving intracellular drug inactivation, low uptake or high efflux of anticancer drugs from cancer cells, qualitative or quantitative changes in the drug target. Many tumors, however, are resistant because of insufficient exposure to anticancer drugs, due to pharmacokinetic reasons and inefficient and heterogeneous tumor drug distribution, related to a deficient vascularization and high interstitial pressure. Finally, resistance can be related to the activation of anti-apoptotic and cell survival pathways by cancer cells and often enhanced by tumor microenvironment.

Valproic Acid as a Promising Co-Treatment With Paclitaxel and Doxorubicin in Different Ovarian Carcinoma Cell Lines

Objective

The current preferred treatment of ovarian cancer is combination chemotherapy, usually a platinum-based drug coupled with paclitaxel (PTX). Here, we investigated whether co-treatment with valproic acid (VPA) could increase the efficiency of various ovarian cancer drugs—PTX, doxorubicin (DOX), carboplatin (CBP), and cyclophosphamide (CP)—in different ovarian cancer cell lines.

Methods

Three different ovarian cancer cell lines (OVCAR-3, TOV-21G, and TOV-112D) were treated with chemotherapeutic drugs, alone or in combination with VPA. Cell viability (XTT assay), caspase-3 activity, and the expression of cell cycle– and apoptosis-related genes and proteins were assessed. Furthermore, the effects of these drugs on α-tubulin acetylation and DNA fragmentation were investigated.

Results

Paclitaxel and DOX decreased cell viability and increased caspase-3 activity, and co-treatment with VPA enhanced this effect. Carboplatin and CP had no effect. Responses to treatment with PAX and DOX together with VPA on gene expression profile were highly variable and depended on the cell line investigated. However, a common feature in all cell lines was an increased expression ofCDKN1A,CCNE1,PARP1, andPARP3. Co-treatment with VPA enhanced the effect of DOX and PAX on most protein expressions investigated in TOV-21G and TOV-112D cell lines, whereas in OVCAR-3, the most effect was seen with DOX with VPA. Valproic acid did not increase PTX-induced α-tubulin acetylation. An additive effect of DOX with VPA on DNA fragmentation was observed in TOV-21G and TOV-112D cell lines but not in the OVCAR-3.

Conclusions

Our results indicate that VPA could be a promising agent in combined anticancer therapy for ovarian cancer, with the combination of VPA and DOX being the most effective. Certainly, additional in vivo and ex vivo experiments are necessary to investigate the molecular mechanisms of action underlying the cellular effects reported here and to study possible clinically relevant effects in ovarian cancer explants.

Progress and potential of RAS mutation detection for diagnostics and companion diagnostics

INTRODUCTION

The importance of RAS mutation in carcinogenesis is established, and knowledge of an individual cancer's mutation status is important for optimal treatment. Areas covered: This paper is restricted to RAS testing in cancer, and highlights papers relevant to current practice. Expert commentary: Multiple laboratory methods are available for RAS gene analysis. PCR is commonly used to determine RAS status, providing a robust and inexpensive technology for clinical use. Next generation sequencing (NGS) platforms are changing the way in which mutation status is determined, though they require considerable expertise. Pre-analytical issues affect both methods and should be considered. The interpretation and reporting of results is not simple, particularly for NGS. External quality assurance is a pre-requisite for success, and is mandated by most laboratory accreditation schemes. The use of RAS testing is now extending beyond biopsy material to include the detection of mutations in circulating cell-free DNA and tumour cells.

ABC-Transporter Expression Does Not Correlate with Response to Irinotecan in Patients with Metastatic Colorectal Cancer

BACKGROUND

Active efflux of irinotecan by ATP-binding cassette (ABC)-transporters, in particular ABCB1 and ABCG2, is a well-established drug resistance mechanism in vitro and in pre-clinical mouse models, but its relevance in colorectal cancer (CRC) patients is unknown. Therefore, we assessed the association between ABC-transporter expression and tumour response to irinotecan in patients with metastatic CRC.

METHODS

Tissue microarrays of a large cohort of metastatic CRC patients treated with irinotecan in a prospective study (CAIRO study; n=566) were analysed for expression of ABCB1 and ABCG2 by immunohistochemistry. Kaplan-Meier and Cox proportional hazard regression analyses were performed to assess the association of ABC transporter expression with irinotecan response. Gene expression profiles of 17 paired tumours were used to assess the concordance of ABCB1/ABCG2 expression in primary CRC and corresponding metastases.

RESULTS

The response to irinotecan was not significantly different between primary tumours with positive versus negative expression of ABCB1 (5.8 vs 5.7 months, p=0.696) or ABCG2 (5.7 vs 6.1 months, p=0.811). Multivariate analysis showed neither ABCB1 nor ABCG2 were independent predictors for progression free survival. There was a mediocre to poor concordance between ABC-transporter expression in paired tumours.

CONCLUSION

In metastatic CRC, ABC-transporter expression in the primary tumour does not predict irinotecan response.

APO866 Increases Antitumor Activity of Cyclosporin-A by Inducing Mitochondrial and Endoplasmic Reticulum Stress in Leukemia Cells

PURPOSE

The nicotinamide phosphoribosyltransferase (NAMPT) inhibitor, APO866, has been previously shown to have antileukemic activity in preclinical models, but its cytotoxicity in primary leukemia cells is frequently limited. The success of current antileukemic treatments is reduced by the occurrence of multidrug resistance, which, in turn, is mediated by membrane transport proteins, such as P-glycoprotein-1 (Pgp). Here, we evaluated the antileukemic effects of APO866 in combination with Pgp inhibitors and studied the mechanisms underlying the interaction between these two types of agents.

EXPERIMENTAL DESIGN

The effects of APO866 with or without Pgp inhibitors were tested on the viability of leukemia cell lines, primary leukemia cells (AML, n = 6; B-CLL, n = 19), and healthy leukocytes. Intracellular nicotinamide adenine dinucleotide (NAD(+)) and ATP levels, mitochondrial transmembrane potential (ΔΨ(m)), markers of apoptosis and of endoplasmic reticulum (ER) stress were evaluated.

RESULTS

The combination of APO866 with Pgp inhibitors resulted in a synergistic cytotoxic effect in leukemia cells, while sparing normal CD34(+) progenitor cells and peripheral blood mononuclear cells. Combining Pgp inhibitors with APO866 led to increased intracellular APO866 levels, compounded NAD(+) and ATP shortage, and induced ΔΨ(m) dissipation. Notably, APO866, Pgp inhibitors and, to a much higher extent, their combination induced ER stress and ER stress inhibition strongly reduced the activity of these treatments.

CONCLUSIONS

APO866 and Pgp inhibitors show a strong synergistic cooperation in leukemia cells, including acute myelogenous leukemia (AML) and B-cell chronic lymphocytic leukemia (B-CLL) samples. Further evaluations of the combination of these agents in clinical setting should be considered.

Prediction of resistance to chemotherapy in ovarian cancer: a systematic review

Background

Patient response to chemotherapy for ovarian cancer is extremely heterogeneous and there are currently no tools to aid the prediction of sensitivity or resistance to chemotherapy and allow treatment stratification. Such a tool could greatly improve patient survival by identifying the most appropriate treatment on a patient-specific basis.

Methods

PubMed was searched for studies predicting response or resistance to chemotherapy using gene expression measurements of human tissue in ovarian cancer.

Results

42 studies were identified and both the data collection and modelling methods were compared. The majority of studies utilised fresh-frozen or formalin-fixed paraffin-embedded tissue. Modelling techniques varied, the most popular being Cox proportional hazards regression and hierarchical clustering which were used by 17 and 11 studies respectively. The gene signatures identified by the various studies were not consistent, with very few genes being identified by more than two studies. Patient cohorts were often noted to be heterogeneous with respect to chemotherapy treatment undergone by patients.

Conclusions

A clinically applicable gene signature capable of predicting patient response to chemotherapy has not yet been identified. Research into a predictive, as opposed to prognostic, model could be highly beneficial and aid the identification of the most suitable treatment for patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1101-8) contains supplementary material, which is available to authorized users.

Role of ABC transporters in fluoropyrimidine-based chemotherapy response

Since over 50 years, 5-fluorouracil (5-FU) is in use as backbone of chemotherapy treatment regimens for a wide range of cancers including colon, breast, and head and neck carcinomas. However, drug resistance and severe toxicities such as mucositis, diarrhea, neutropenia, and vomiting in up to 40% of treated patients often lead to dose limitation or treatment discontinuation. Because the oral bioavailability of 5-FU is unpredictable and highly variable, 5-FU is commonly administered intravenously. To overcome medical complications and inconvenience associated with intravenous administration, the oral prodrugs capecitabine and tegafur have been developed. Both fluoropyrimidines are metabolically converted intracellularly to 5-FU, which then needs metabolic activation to exert its damaging activity on RNA and DNA. The low response rates of 10-15% of 5-FU monotherapy can be improved by combination regimens of infusional 5-FU and leucovorin together with oxaliplatin (FOLFOX) or irinotecan (FOLFIRI), thereby increasing response rates to 30-40%. The impact of metabolizing enzymes in the development of fluoropyrimidine toxicity and resistance has been studied in great detail. In addition, membrane drug transporters, which are critical determinants of intracellular drug concentrations, may play a role in occurrence of toxicity and development of resistance against fluoropyrimidine-based therapy as well. This review therefore summarizes current knowledge on the role of drug transporters with particular focus on ATP-binding cassette transporters in fluoropyrimidine-based chemotherapy response.

Effect of Chemotherapeutic Drugs on Caspase-3 Activity, as a Key Biomarker for Apoptosis in Ovarian Tumor Cell Cultured as Monolayer. A Pilot Study

We aimed to develop a cost-effective and robust method to predict drug resistance in individual patients. Representative tissue fragments were obtained from tumors removed from female patients, aged 24-74 years old. The tumor tissue was taken by a histopathology's or a surgeon under sterile conditions. Cells obtained by enzymatic dissociation from tumor after surgery, were cultured as a monolayer for 6 days. Paclitaxel, doxorubicin, carboplatin and endoxan alone or in combination were added at the beginning of culture and after 6 days, Alamar blue test was used for showing action on cell proliferation why caspase- 3 activity assays for verifying action on apoptosis. Inhibitory action on cell proliferation was noted in 2 of 12 patients tumor treated with both single and combined drugs. Using caspase-3 assay we showed that 50% of tumor cells was resistant to single chemotherapeutic drugs and 40% for combined. In 2 of 12 tumors, which did not reacted on single drugs, positive synergistic action on cell proliferation was observed in combination of D + E and C + E. This pilot study suggests: 1) monolayer culture of tumor cells, derived from individual patients, before chemotherapy could provide a suitable model for studying resistance for drugs; 2) caspase-3 activity is cheap and useful methods; 3) Alamar blue test should be taken into consideration for measuring cell proliferation.

The significance of reduced glutathione and glutathione S-transferase during chemoradiotherapy of locally advanced cervical cancer

BACKGROUND AND OBJECTIVE

To determine changes in reduced glutathione (GSH) and glutathione S-transferase (GST) during neoadjuvant chemotherapy followed by concurrent chemoradiation for patients with stage IIB-IIIB cervical cancer, and to evaluate their significance to the efficacy of the treatment.

MATERIALS AND METHODS

According to the prospective phase II study protocol, 36 patients with stage IIB-IIIB cervical cancer were enrolled. A short course of intensive weekly neoadjuvant cisplatin and gemcitabine chemotherapy followed by concurrent weekly cisplatin and gemcitabine-based chemoradiation was administered. Blood samples for GSH, GST analysis were collected and analyzed before the start of the treatment, after neoadjuvant chemotherapy, and after the end of the chemoradiation.

RESULTS

A statistically significant increase in the concentration of GSH after neoadjuvant chemotherapy was identified. After chemoradiation, values of this rate significantly decreased in contrast with GSH concentration after neoadjuvant chemotherapy in cases of stage IIB, regional metastases negative patients group, patients with a positive response to treatment, and patients who had no progression of the disease during the first 2 years after treatment. Statistically significant changes in GST during the treatment were not identified; the GST concentration after chemoradiation showed a statistically significant difference in GST concentrations in terms of the progression of the disease and disease without progression.

CONCLUSIONS

The results suggest that changes in the concentration of GSH during the treatment of locally advanced cervical cancer might be important for the prediction of the efficacy of the treatment. Statistically significant changes in GST concentration levels during the treatment were not observed.

Data-derived modeling characterizes plasticity of MAPK signaling in melanoma

The majority of melanomas have been shown to harbor somatic mutations in the RAS-RAF-MEK-MAPK and PI3K-AKT pathways, which play a major role in regulation of proliferation and survival. The prevalence of these mutations makes these kinase signal transduction pathways an attractive target for cancer therapy. However, tumors have generally shown adaptive resistance to treatment. This adaptation is achieved in melanoma through its ability to undergo neovascularization, migration and rearrangement of signaling pathways. To understand the dynamic, nonlinear behavior of signaling pathways in cancer, several computational modeling approaches have been suggested. Most of those models require that the pathway topology remains constant over the entire observation period. However, changes in topology might underlie adaptive behavior to drug treatment. To study signaling rearrangements, here we present a new approach based on Fuzzy Logic (FL) that predicts changes in network architecture over time. This adaptive modeling approach was used to investigate pathway dynamics in a newly acquired experimental dataset describing total and phosphorylated protein signaling over four days in A375 melanoma cell line exposed to different kinase inhibitors. First, a generalized strategy was established to implement a parameter-reduced FL model encoding non-linear activity of a signaling network in response to perturbation. Next, a literature-based topology was generated and parameters of the FL model were derived from the full experimental dataset. Subsequently, the temporal evolution of model performance was evaluated by leaving time-defined data points out of training. Emerging discrepancies between model predictions and experimental data at specific time points allowed the characterization of potential network rearrangement. We demonstrate that this adaptive FL modeling approach helps to enhance our mechanistic understanding of the molecular plasticity of melanoma.

Signal transduction pathways can be described as static routes, transmitting extrinsic signals to the nucleus to induce a transcriptional response. In contrast to this reductionist view, the emerging paradigm is that signaling networks undergo dynamic crosstalk, both in disease and physiological conditions. To understand complex pathway behavior, it is necessary to develop methods to identify pathway interactions that are active as a consequence of stimuli and, importantly, to describe their evolution in time. To that end, we developed a method relying on prior knowledge networks in order to predict signaling crosstalk evolution, in response to perturbation and over time. The challenge we addressed was to establish a method dependent on information related to the topology of reported interactions, and not their mechanistic characteristics, and at the same time complex enough to reproduce the behavior of the signaling intermediates. The work presented here demonstrates that such an approach can be used to predict mechanisms that melanoma uses to rearrange its signaling and maintain its abnormal proliferation upon treatment.

Guidance for laboratories performing molecular pathology for cancer patients

Molecular testing is becoming an important part of the diagnosis of any patient with cancer. The challenge to laboratories is to meet this need, using reliable methods and processes to ensure that patients receive a timely and accurate report on which their treatment will be based. The aim of this paper is to provide minimum requirements for the management of molecular pathology laboratories. This general guidance should be augmented by the specific guidance available for different tumour types and tests. Preanalytical considerations are important, and careful consideration of the way in which specimens are obtained and reach the laboratory is necessary. Sample receipt and handling follow standard operating procedures, but some alterations may be necessary if molecular testing is to be performed, for instance to control tissue fixation. DNA and RNA extraction can be standardised and should be checked for quality and quantity of output on a regular basis. The choice of analytical method(s) depends on clinical requirements, desired turnaround time, and expertise available. Internal quality control, regular internal audit of the whole testing process, laboratory accreditation, and continual participation in external quality assessment schemes are prerequisites for delivery of a reliable service. A molecular pathology report should accurately convey the information the clinician needs to treat the patient with sufficient information to allow for correct interpretation of the result. Molecular pathology is developing rapidly, and further detailed evidence-based recommendations are required for many of the topics covered here.