What links BRAF to the heart function? New insights from the cardiotoxicity of BRAF inhibitors in cancer treatment

The RAS-related signalling cascade has a fundamental role in cell. It activates differentiation and survival. It is particularly important one of its molecules, B-RAF. B-RAF has been a central point for research, especially in melanoma. Indeed, it lacked effective therapeutic weapons since the early years of its study. Molecules targeting B-RAF have been developed. Nowadays, two classes of molecules are approved by FDA. Multi-target molecules, such as Sorafenib and Regorafenib, and selective molecules, such as Vemurafenib and Dabrafenib. Many other molecules are still under investigation. Most of them are studied in phase 1 trials. Clinical studies correlate B-RAF inhibitors and QT prolongation. Though this cardiovascular side effect is not common using these drugs, it must be noticed early and recognize its signals. Indeed, Oncologists and Cardiologists should work in cooperation to prevent lethal events, such as fatal arrhythmias or sudden cardiac death. These events could originate from an uncontrolled QT prolongation.

New findings on primary and acquired resistance to anti-EGFR therapy in metastatic colorectal cancer: do all roads lead to RAS?

Anti-epidermal growth factor receptor therapy with the monoclonal antibodies cetuximab and panitumumab is the main targeted treatment to combine with standard chemotherapy for metastatic colorectal cancer. Many clinical studies have shown the benefit of the addition of these agents for patients without mutations in the EGFR pathway. Many biomarkers, including KRAS and NRAS mutations, BRAF mutations, PIK3CA mutations, PTEN loss, AREG and EREG expression, and HER-2 amplification have already been identified to select responders to anti-EGFR agents. Among these alterations KRAS and NRAS mutations are currently recognized as the best predictive factors for primary resistance. Liquid biopsy, which helps to isolate circulating tumor DNA, is an innovative method to study both primary and acquired resistance to anti-EGFR monoclonal antibodies. However, high-sensitivity techniques should be used to enable the identification of a wide set of gene mutations related to resistance.

Abstract 1855: Role of mTOR inhibition in triple-negative breast cancer

BACKGROUND:

Triple-negative breast cancers (TNBC) represent the 10-17% of all diagnosed breast cancers (BC) and are characterized by the absence of ER/PgR expression, HER2 amplification and often show a basal-like phenotype. TNBC are often diagnosed in patients with BRCA1 germline mutation and unfortunately treatment options are still limited. The mTOR (Mammalian Target Of Rapamycin) pathway seems to play an important role in BC pathogenesis and it is possible to target this pathway by inhibitors such as rapamycin. In human BC cross talk between ER/PgR receptors signaling and the mTOR pathway is believed to be responsible for resistance to hormone therapy probably due to a down regulation of hormone receptors. Based on these evidences we have hypothesized that the inhibitors of mTOR pathway may lead to the up-regulation of ER, PgR and HER2 in TNBC cell lines.

METHODS:

For this study we used TNBC cells (MDA-MB-231 and BT20) cultured in DMEM:F12 (Dulbecco's Modified Eagle's Medium) with 10% bovine serum (FBS), 100 U/mL penicillin (1%) and 50 mg/mL of streptomycin under standard conditions (37°C in an atmosphere composed of 16% O2, 79% N2 and 5% CO2).

Cells were initially treated with Rapamycin (1, 5, 10, 15 microM) for 24, 48, and 72h in order to verify if the drug determines a blockade of cell proliferation. Before drug administration, the cells were subjected to serum starvation by eliminating serum from culture medium. The evaluation of cell viability following the administration of the drug was carried out using the MTT assay. Real time PCR analyses were carried out in order to evaluate gene expression modifications of ER, PgR and HER2 receptors, through Taqman probe chemistry.

RESULTS:

The preliminary cell viability experiments conducted on different TNBC cell lines (MDA-MB-231 and BT20), showed no significant cytotoxic effects by increasing Rapamycin concentrations (1, 5 and 10 microM) after 72h treatment, except for the higher concentration (15 microM) for which a cytotoxic effect was observed.

The following qPCR approach highlighted significant variations in estrogen and progesterone receptor gene expression for the TNBC cell lines after 24, 48, 72h with 1, 5, 10 microM Rapamycin. In particular their expression level resulted up-regulated. Unlikely no association between mTOR inhibition and HER2 expression level were identified, suggesting no effects of mTOR inhibition on HER2 expression.

CONCLUSION AND FUTURE PERSPECTIVES:

To these preliminary results suggest that the mTOR inhibition leads to re-expression of hormone receptors. This finding supports a potential clinical application of mTOR inhibition in TNBC. The perspective of phenotype change upon rapamycin treatment prompts new therapeutic scenarios. However, further investigations are needed to explain the biological mechanisms driving these changes.

Citation Format: Daniela Massihnia, Giuseppe Bronte, Marta Castiglia, Nadia Barraco, Antonina Cangemi, Alessandro Perez, Daniele Fanale, Gianni Pantuso, Salvatore Vieni, Valentina Calò, Christian D. Rolfo, Viviana Bazan, Antonio Russo. Role of mTOR inhibition in triple-negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1855.

Beyond evidence-based data: scientific rationale and tumor behavior to drive sequential and personalized therapeutic strategies for the treatment of metastatic renal cell carcinoma

The recent advances in identification of the molecular mechanisms related to tumorigenesis and angiogenesis, along with the understanding of molecular alterations involved in renal cell carcinoma (RCC) pathogenesis, has allowed the development of several new drugs which have revolutionized the treatment of metastatic renal cell carcinoma (mRCC).This process has resulted in clinically significant improvements in median overall survival and an increasing number of patients undergoes two or even three lines of therapy. Therefore, it is necessary a long-term perspective of the treatment: planning a sequential and personalized therapeutic strategy to improve clinical outcome, the potential to achieve long-term response, and to preserve quality of life (QOL), minimizing treatment-related toxicity and transforming mRCC into a chronically treatable condition.Because of the challenges still encountered to draw an optimal therapeutic sequence, the main focus of this article will be to propose the optimal sequencing of existing, approved, oral targeted agents for the treatment of mRCC using evidence-based data along with the knowledge available on the tumor behavior and mechanisms of resistance to anti-angiogenic treatment to provide complementary information and to help the clinicians to maximize the effectiveness of targeted agents in the treatment of mRCC.

Dietary restriction: could it be considered as speed bump on tumor progression road?

Dietary restrictions, including fasting (or long-term starvation), calorie restriction (CR), and short-term starvation (STS), are considered a strong rationale that may protect against various diseases, including age-related diseases and cancer. Among dietary approaches, STS, in which food is not consumed during designed fasting periods but is typically not restricted during designated feeding periods, seems to be more suitable, because other dietary regimens involving prolonged fasting periods could worsen the health conditions of cancer patients, being they already naturally prone to weight loss. Until now, the limited amount of available data does not point to a single gene, pathway, or molecular mechanism underlying the benefits to the different dietary approaches. It is well known that the healthy effect is mediated in part by the reduction of nutrient-related pathways. The calorie restriction and starvation (long- and short-term) also suppress the inflammatory response reducing the expression, for example, of IL-10 and TNF-α, mitigating pro-inflammatory gene expression and increasing anti-inflammatory gene expression. The dietary restriction may regulate both genes involved in cellular proliferation and factors associated to apoptosis in normal and cancer cells. Finally, dietary restriction is an important tool that may influence the response to chemotherapy in preclinical models. However, further data are needed to correlate dietary approaches with chemotherapeutic treatments in human models. The aim of this review is to discuss the effects of various dietary approaches on the cancer progression and therapy response, mainly in preclinical models, describing some signaling pathways involved in these processes.

Nintedanib in NSCLC: evidence to date and place in therapy

The treatment of advanced non-small cell lung cancer (NSCLC) is currently driven by the detection of targetable oncogenic drivers, i.e. epidermal growth factor receptor, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase, etc. Those patients who are wildtype for known and valuable oncogenes can receive standard chemotherapy as first-line treatment, with the possibility of adding bevacizumab. With regard to second-line treatment, nintedanib can improve the efficacy of docetaxel. Nintedanib is a tyrosine kinase inhibitor targeting three angiogenesis-related transmembrane receptors. The usefulness of nintedanib as an anticancer agent for NSCLC has been proved by both preclinical and clinical phase I and II trials; however, its approval for the use in clinical practice has been possible because of the positive results of the LUME-Lung 1 trial (nintedanib + docetaxel versus docetaxel alone) in terms of progression-free survival and overall survival, and a manageable tolerability profile. Therefore, the good results seen in the clinical trials with nintedanib in the second-line setting for NSCLC patients with adenocarcinoma subtype are encouraging enough to recommend it in clinical practice.

Non-coding RNAs Functioning in Colorectal Cancer Stem Cells

In recent years, the hypothesis of the presence of tumor-initiating cancer stem cells (CSCs) has received a considerable support. This model suggested the existence of CSCs which, thanks to their self-renewal properties, are able to drive the expansion and the maintenance of malignant cell populations with invasive and metastatic potential in cancer. Increasing evidence showed the ability of such cells to acquire self-renewal, multipotency, angiogenic potential, immune evasion, symmetrical and asymmetrical divisions which, along with the presence of several DNA repair mechanisms, further enhance their oncogenic potential making them highly resistant to common anticancer treatments. The main signaling pathways involved in the homeostasis of colorectal (CRC) stem cells are the Wnt, Notch, Sonic Hedgehog, and Bone Morfogenic Protein (BMP) pathways, which are mostly responsible for all the features that have been widely referred to stem cells. The same pathways have been identified in colorectal cancer stem cells (CRCSCs), conferring a more aggressive phenotype compared to non-stem CRC cells. Recently, several evidences suggested that non-coding RNAs (ncRNAs) may play a crucial role in the regulation of different biological mechanisms in CRC, by modulating the expression of critical stem cell transcription factors that have been found active in CSCs. In this chapter, we will discuss the involvement of ncRNAs, especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in stemness acquisition and maintenance by CRCSCs, through the regulation of pathways modulating the CSC phenotype and growth, carcinogenesis, differentiation, and epithelial to mesenchymal transition (EMT).

Impact of microRNAs in resistance to chemotherapy and novel targeted agents in non-small cell lung cancer

Despite recent advances in understanding the cancer signaling pathways and in developing new therapeutic strategies, non-small cell lung cancer (NSCLC) shows grim prognosis and high incidence of recurrence. Insufficient disruption of oncogenic signaling and drug resistance are the most common causes of tumor recurrence. Drug resistance, intrinsic or acquired, represents a main obstacle in NSCLC therapeutics by limiting the efficacy both of conventional chemotherapeutic compounds and new targeted agents. Therefore, novel and more innovative approaches are required for treatment of this tumor. MicroRNAs (miRNAs) are a family of small non-coding RNAs that regulate gene expression by sequence-specific targeting of mRNAs causing mRNA degradation or translational repression. Accumulating evidence suggests that impairment of candidate miRNAs may be involved in the acquisition of tumor cell resistance to conventional chemotherapy and novel biological agents by affecting the drug sensitivity of cancer cells. The modulation of these miRNAs, using antagomiRs or miRNA mimics, can restore key gene networks and signaling pathways, and optimize anticancer therapies by inhibition of tumor cell proliferation and increasing the drug sensitivity. Therefore, miRNA-based therapeutics provides an attractive anti-tumor approach for developing new and more effective individualized therapeutic strategies, improving drug efficiency, and for predicting the response to different anticancer drugs. In this review, we present an overview on the role of miRNAs in resistance mechanisms of NSCLC, discussing the main studies on the aberrations in apoptosis, cell cycle and DNA damage repair pathways, as well as in novel drug targets.

Conquests and perspectives of cardio-oncology in the field of tumor angiogenesis-targeting tyrosine kinase inhibitor-based therapy

INTRODUCTION

Angiogenesis is fundamental for tumor development and progression. Hence, anti-angiogenic drugs have been developed to target VEGF and its receptors (VEGFRs). Several tyrosine kinase inhibitors (TKIs) have been developed over the years and others are still under investigation, each anti-VEGFR TKI showing a different cardiotoxic profile. Knowledge of the cardiac side-effects of each drug and the magnitude of their expression and frequency can lead to a specific approach.

AREAS COVERED

This work reviews the mechanism of action of anti-VEGFR TKIs and the pathophysiological mechanisms leading to cardiotoxicity, followed by close examination of the most important drugs individually. A literature search was conducted on PubMed selecting review articles, original studies and clinical trials, with a focus on Phase III studies.

EXPERT OPINION

Side-effects on the cardiovascular system could lead both to the worsening of general health status of cancer patients and to the discontinuation of the cancer treatment affecting its efficacy. Cardiologists often have to face new triggers of heart disease in these patients. They need a specific approach, which must be carried out in cooperation with oncologists. It must start before cancer treatment, continue during it and extend after its completion.

Farletuzumab for NSCLC: exploiting a well-known metabolic pathway for a new therapeutic strategy

Introduction: The therapeutic options for NSCLC are limited barring targeted drugs, such as EGFR tyrosine-kinase inhibitors and anaplastic lymphoma kinase inhibitors, for patients bearing oncogenic mutations. Platinum-based chemotherapy remains the best strategy for most patients. New targeted drugs, including mAbs and small molecules, are currently under clinical investigation for treating NSCLC patients. Areas covered: The authors of this article focus on farletuzumab , a mAb targeting folate receptor, which has been studied in ovarian cancer and various other malignancies. In this review, the authors review its potential as therapy for NSCLC, because of the biological rationale provided by the expression of folate receptor α in most of lung adenocarcinoma. The authors provide details of farletuzumab's mechanism of action and discuss the results from completed Phase I and Phase II clinical trials. They also highlight ongoing trials. Expert opinion: There are an increasing number of treatment options for NSCLC and it is hoped that farletuzumab could be added to them. That being said, further evidence for its use with NSCLC patients is still needed. It could have a synergic effect with pemetrexed, because these two drugs have a similar target, namely the folate pathway. This combined action could provide an improved efficacy, although there are some concerns about increased toxicity. However, the authors do note that the combination of farletuzumab with other cytotoxic drugs has not been shown to increase toxicity alone.

Abstract 448: Molecular analysis of BRAF gene and PTEN gene expression in metastatic colorectal cancer patients: Feasibility study

Introduction There are numerous causes triggering CRC. 25-80% of CRC shown a deregulation in Epidermal Growth Factor Receptor (EGFR) pathway. Two signaling pathways downstream of the EGFR are dysregulated in CRC the mitogen-activated protein kinase (MAPK) and the phosphoinositide-3-kinase (PI3K) pathway. Activating mutations in KRAS and BRAF (MAPK pathway) and PIK3CA affect prognosis and/or response to anti-EGFR MoAb. PTEN is a downstream effector of EGFR pathway and is involved in PI3K pathway. Loss of PTEN protein expression can occur through epigenetic silencing and mutation or allelic loss. Immunohistochemistry (IHC) is the most effective way to assay for loss of PTEN expression. IHC lack of reproducibility and this has lead to discordant results regarding the concordant in paired CRC metastases and primary tumors.The aim of the work was to asses the feasibility of PTEN gene expression analysis from FFPE tissue in CRC samples.

Materials and methods We selected a series of 33 patients, already tested for KRAS mutational status and resulted wild-type. At the time of the study mutational status of NRAS gene has not a role as predictive marker, so was not performed. A retrospective analysis on CRC FFPE tissue was performed. As control samples we have selected specimen of colorectal surgery not tumor-associated (diverticulitis). On these samples BRAF mutational analysis and PTEN gene expression was performed. For BRAF analysis, DNA was extracted by means of QIAamp DNA FFPE tissue kit (Qiagen, USA). BRAF mutational status was assed through direct automated sequencing (3100 Genetic Analyzer, Applied Biosystems) and TaqMan mutation detection assay (ABI PRIM 7900HT, Applied Biosystems). For PTEN gene expression, total RNA was obtained through the miRNeasy FFPE tissue kit (Qiagen, USA), according to manufacturer instructions, and reverse transcribed. PTEN expression was assessed by means of TaqMan probes.

Results According to BRAF mutational status we have found 10/33 (30%) mutated samples. PTEN expression levels were evaluated by the comparison of tumor samples vs diverticula samples, the data obtained were then integrated with those from BRAF mutational analysis. Interestingly we found that all the BRAF mutated samples present also a down-regulation of PTEN. Statistical analyses were conducted through the X2 test with the Yatesha correction (p=0.00023). The p-value was also calculated Exact Fisher Test (p= 0.00021) to confirm the results.

Conclusion The determination of PTEN gene expression level is feasible with real-time PCR using TaqMan probe technology. BRAF analysis might be used as prognostic and/or predictive marker in CRC patients’ treatment. The identification of a validated method for PTEN analysis would establish it as a molecular marker meriting further investigation in large numbers of available primary tumors from patients with CRC. Further analyses are requested to confirm these data.

Citation Format: Christian D. Rolfo, Marta Castiglia, Daniela Cabibi, Valentina Calo', Florinda Di Piazza, Viviana Bazan, Fabio Brocco, Stefano Caruso, Loredana Bruno, Konstantinos Papadimitriou, Francesco Passiglia, Marc Peeters, Patrick Pauwels, Antonio Russo. Molecular analysis of BRAF gene and PTEN gene expression in metastatic colorectal cancer patients: Feasibility study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 448. doi:10.1158/1538-7445.AM2014-448

Ramucirumab and its use in gastric cancer treatment

The inhibition of the mechanisms of tumor neo-angiogenesis represents a milestone that in the last 10 years has seen the advent of numerous molecules to target action against the vascular endothelial growth factor (VEGF). More recently, new molecules have been developed that inhibit tumor spread by the blockade of specific VEGF receptors (VEGFRs), thereby preventing the binding of a ligand to its receptor and the cascade of proliferative events downstream. Ramucirumab is a fully humanized IgG1 monoclonal antibody that performs its action by blocking the isoform 2 of the VEGF receptor (VEGFR-2). Numerous preclinical and clinical studies have demonstrated its activity in several solid tumors, demonstrating a remarkable efficacy in terms of progression-free survival and overall survival in addition to a favorable toxicity profile. This review analyzes in detail the role of ramucirumab in the treatment of advanced gastric and gastroesophageal junction cancers.

Germline copy number variation in the YTHDC2 gene: does it have a role in finding a novel potential molecular target involved in pancreatic adenocarcinoma susceptibility?

OBJECTIVE

The vast majority of pancreatic cancers occurs sporadically. The discovery of frequent variations in germline gene copy number can significantly influence the expression levels of genes that predispose to pancreatic adenocarcinoma. We prospectively investigated whether patients with sporadic pancreatic adenocarcinoma share specific gene copy number variations (CNVs) in their germline DNA.

PATIENTS AND METHODS

DNA samples were analyzed from peripheral leukocytes from 72 patients with a diagnosis of sporadic pancreatic adenocarcinoma and from 60 controls using Affymetrix 500K array set. Multiplex ligation-dependent probe amplification (MLPA) assay was performed using a set of self-designed MLPA probes specific for seven target sequences.

RESULTS

We identified a CNV-containing DNA region associated with pancreatic cancer risk. This region shows a deletion of 1 allele in 36 of the 72 analyzed patients but in none of the controls. This region is of particular interest since it contains the YTHDC2 gene encoding for a putative DNA/RNA helicase, such protein being frequently involved in cancer susceptibility. Interestingly, 82.6% of Sicilian patients showed germline loss of one allele.

CONCLUSIONS

Our results suggest that the YTHDC2 gene could be a potential candidate for pancreatic cancer susceptibility and a useful marker for early detection as well as for the development of possible new therapeutic strategies.