BRAF(E600) in benign and malignant human tumours

Frequency of BRAF Mutations in Dysplastic Nevi, Lentigo Maligna, and Melanoma In Situ

Background: In melanomas, mutations in the BRAF gene are common and their occurrence represents an early oncogenic event. Our goal was to determine and compare the frequency of BRAF gene mutations in dysplastic nevi (ND) and melanomas in situ (MIS), as well as whether there is a correlation between the presence of BRAF gene mutations and various anamnestic, clinical, and histopathologic variables. Methods: A total of 175 patients-106 with ND, 41 with MIS, and 28 with lentigo maligna (LM) were included in the study. DNA was extracted from tissue samples and analyzed using the competitive allele-specific TaqMan chain reaction by polymerase in real time to detect the presence of BRAF V600E and V600K mutations. The data were compared with anamnestic, clinical, and histopathological data. Results: There is a statistically significant correlation between the presence of BRAF mutation and the diagnosis of melanoma in situ (χ2 test, χ2 = 29.17, p < 0.0001). Patients with LM had a significantly lower incidence of BRAF mutations compared to patients with ND and MIS. There was a significant correlation between the presence of a BRAF mutation and tumor localization, as well as the age of the patient, but no statistically significant correlation between the presence of a BRAF mutation and sex, tumor size, or previous melanoma diagnosis. Conclusions: BRAF mutations in ND are essentially required; however, they are an insufficient oncogenic trigger for the development of melanoma. This research contributes to a better understanding of the etiopathogenesis of melanoma and the role of ND as possible precursor lesions.

DNA Sequencing of CD138 Cell Population Reveals TP53 and RAS-MAPK Mutations in Multiple Myeloma at Diagnosis

Multiple myeloma is a hematologic neoplasm caused by abnormal proliferation of plasma cells. Sequencing studies suggest that plasma cell disorders are caused by both cytogenetic abnormalities and oncogene mutations. Therefore, it is necessary to detect molecular abnormalities to improve the diagnosis and management of MM. The main purpose of this study is to determine whether NGS, in addition to cytogenetics, can influence risk stratification and management. Additionally, we aim to establish whether mutational analysis of the CD138 cell population is a suitable option for the characterization of MM compared to the bulk population. Following the separation of the plasma cells harvested from 35 patients newly diagnosed with MM, we performed a FISH analysis to detect the most common chromosomal abnormalities. Consecutively, we used NGS to evaluate NRAS, KRAS, BRAF, and TP53 mutations in plasma cell populations and in bone marrow samples. NGS data showed that sequencing CD138 cells provides a more sensitive approach. We identified several variants in BRAF, KRAS, and TP53 that were not previously associated with MM. Considering that the presence of somatic mutations could influence risk stratification and therapeutic approaches of patients with MM, sensitive detection of these mutations at diagnosis is essential for optimal management of MM.

Synthesis and anti-tumor activity evaluation of 1H-pyrrolo[2,3-b]pyridine-2-carboxamide derivatives with phenyl sulfonamide groups as potent RSK2 inhibitors

Ribosome S6 Protein Kinase 2 (RSK2) is involved in many signal pathways such as cell growth, proliferation, survival and migration in tumors. Also, RSK2 can phosphorylate YB-1, which induces the expression of tumor initiating cells, leading to poor prognosis of triple negative breast cancer. Herein, phenyl sulfonamide was introduced to a series of 1H-pyrrolo[2,3-b]pyridine-2-carboxamide derivatives to obtain novel RSK2 inhibitors which were evaluated RSK2 inhibitory activity and proliferation inhibitory activity against MDA-MB-468. The newly introduced sulfonamide group was observed to form a hydrogen bond with target residue LEU-74 which played crucial role in activity. The results showed that most of compounds exhibited RSK2 enzyme inhibitory with IC50 up to 1.7 nM. Compound B1 exhibited the strongest MDA-MB-468 cell anti-proliferation activity (IC50  = 0.13 μM). The in vivo tumor growth inhibitory activities were evaluated with compounds B1-B3 in MDA-MB-468 xenograft model which gave up to 54.6% of TGI.

Spatial resolution of cellular senescence dynamics in human colorectal liver metastasis

Hepatic metastasis is a clinical challenge for colorectal cancer (CRC). Senescent cancer cells accumulate in CRC favoring tumor dissemination. Whether this mechanism progresses also in metastasis is unexplored. Here, we integrated spatial transcriptomics, 3D-microscopy, and multicellular transcriptomics to study the role of cellular senescence in human colorectal liver metastasis (CRLM). We discovered two distinct senescent metastatic cancer cell (SMCC) subtypes, transcriptionally located at the opposite pole of epithelial (e) to mesenchymal (m) transition. SMCCs differ in chemotherapy susceptibility, biological program, and prognostic roles. Mechanistically, epithelial (e)SMCC initiation relies on nucleolar stress, whereby c-myc dependent oncogene hyperactivation induces ribosomal RPL11 accumulation and DNA damage response. In a 2D pre-clinical model, we demonstrated that RPL11 co-localized with HDM2, a p53-specific ubiquitin ligase, leading to senescence activation in (e)SMCCs. On the contrary, mesenchymal (m)SMCCs undergo TGFβ paracrine activation of NOX4-p15 effectors. SMCCs display opposing effects also in the immune regulation of neighboring cells, establishing an immunosuppressive environment or leading to an active immune workflow. Both SMCC signatures are predictive biomarkers whose unbalanced ratio determined the clinical outcome in CRLM and CRC patients. Altogether, we provide a comprehensive new understanding of the role of SMCCs in CRLM and highlight their potential as new therapeutic targets to limit CRLM progression.

Current Advances in Papillary Craniopharyngioma: State-Of-The-Art Therapies and Overview of the Literature

Craniopharyngiomas are commonly classified as low-grade tumors, although they may harbor a malignant behavior due to their high rate of recurrence and long-term morbidity. Craniopharyngiomas are classically distinguished into two histological types (adamantinomatous and papillary), which have been recently considered by the WHO classification of CNS tumors as two independent entities, due to different epidemiological, radiological, histopathological, and genetic patterns. With regard to papillary craniopharyngioma, a BRAF V600 mutation is detected in 95% of cases. This genetic feature is opening new frontiers in the treatment of these tumors using an adjuvant or, in selected cases, a neo-adjuvant approach. In this article, we present an overview of the more recent literature, focusing on the specificities and the role of oncological treatment in the management of papillary craniopharyngiomas. Based on our research and experience, we strongly suggest a multimodal approach combining clinical, endocrinological, radiological, histological, and oncological findings in both preoperative workup and postoperative follow up to define a roadmap integrating every aspect of this challenging condition.

Multi-range ERK responses shape the proliferative trajectory of single cells following oncogene induction

Oncogene-induced senescence is a phenomenon in which aberrant oncogene expression causes non-transformed cells to enter a non-proliferative state. Cells undergoing oncogenic induction display phenotypic heterogeneity, with some cells senescing and others remaining proliferative. The causes of heterogeneity remain unclear. We studied the sources of heterogeneity in the responses of human epithelial cells to oncogenic BRAF^V600E expression. We found that a narrow expression range of BRAF^V600E generated a wide range of activities of its downstream effector ERK. In population-level and single-cell assays, ERK activity displayed a non-monotonic relationship to proliferation, with intermediate ERK activities leading to maximal proliferation. We profiled gene expression across a range of ERK activities over time and characterized four distinct ERK response classes, which we propose act in concert to generate the ERK-proliferation response. Altogether, our studies map the input-output relationships between ERK activity and proliferation, elucidating how heterogeneity can be generated during oncogene induction.

Recent and Future Strategies to Overcome Resistance to Targeted Therapies and Immunotherapies in Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related deaths worldwide, and 20% of patients with CRC present at diagnosis with metastases. The treatment of metastatic CRC is based on a fluoropyrimidine-based chemotherapy plus additional agents such as oxaliplatin and irinotecan. To date, on the basis of the molecular background, targeted therapies (e.g., monoclonal antibodies against epidermal growth factor receptor or inhibiting angiogenesis) are administered to improve the treatment of metastatic CRC. In addition, more recently, immunological agents emerged as effective in patients with a defective mismatch repair system. The administration of targeted therapies and immunotherapy lead to a significant increase in the survival of patients; however these drugs do not always prove effective. In most cases the lack of effectiveness is due to the development of primary resistance, either a resistance-inducing factor is already present before treatment or resistance is acquired when it occurs after treatment initiation. In this review we describe the most relevant targeted therapies and immunotherapies and expand on the reasons for resistance to the different approved or under development targeted drugs. Then we showed the possible mechanisms and drugs that may lead to overcoming the primary or acquired resistance in metastatic CRC.

BRAFV600E in colorectal cancer reduces sensitivity to oxidative stress and promotes site-specific metastasis by stimulating glutathione synthesis

The presence of BRAF^V600E in colorectal cancer (CRC) is associated with a higher chance of distant metastasis. Oxidative stress in disseminated tumor cells limits metastatic capacity. To study the relationship between BRAF^V600E, sensitivity to oxidative stress, and metastatic capacity in CRC, we use patient-derived organoids (PDOs) and tissue samples. BRAF^V600E tumors and PDOs express high levels of glutamate-cysteine ligase (GCL), the rate-limiting enzyme in glutathione synthesis. Deletion of GCL in BRAF^V600E PDOs strongly reduces their capacity to form distant liver and lung metastases but does not affect peritoneal metastasis outgrowth. Vice versa, the glutathione precursor N-acetyl-cysteine promotes organ-site-specific metastasis in the liver and the lungs but not in the peritoneum. BRAF^V600E confers resistance to pharmacologically induced oxidative stress in vitro, which is partially overcome by treatment with the BRAF-inhibitor vemurafenib. We conclude that GCL-driven glutathione synthesis protects BRAF^V600E-expressing tumors from oxidative stress during distant metastasis to the liver and the lungs.

cAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach

Cancer is one of the most common causes of death globally. Despite extensive research and considerable advances in cancer therapy, the fundamentals of the disease remain unclear. Understanding the key signaling mechanisms that cause cancer cell malignancy may help to uncover new pharmaco-targets. Cyclic adenosine monophosphate (cAMP) regulates various biological functions, including those in malignant cells. Understanding intracellular second messenger pathways is crucial for identifying downstream proteins involved in cancer growth and development. cAMP regulates cell signaling and a variety of physiological and pathological activities. There may be an impact on gene transcription from protein kinase A (PKA) as well as its downstream effectors, such as cAMP response element-binding protein (CREB). The position of CREB downstream of numerous growth signaling pathways implies its oncogenic potential in tumor cells. Tumor growth is associated with increased CREB expression and activation. PKA can be used as both an onco-drug target and a biomarker to find, identify, and stage tumors. Exploring cAMP effectors and their downstream pathways in cancer has become easier using exchange protein directly activated by cAMP (EPAC) modulators. This signaling system may inhibit or accelerate tumor growth depending on the tumor and its environment. As cAMP and its effectors are critical for cancer development, targeting them may be a useful cancer treatment strategy. Moreover, by reviewing the material from a distinct viewpoint, this review aims to give a knowledge of the impact of the cAMP signaling pathway and the related effectors on cancer incidence and development. These innovative insights seek to encourage the development of novel treatment techniques and new approaches.

Exploring biological heterogeneity and implications on novel treatment paradigm in BRAF-mutant metastatic colorectal cancer

Approximatively 8-15% of patients with metastatic colorectal cancer (mCRC) harbor mutation in BRAF gene. Recent advances in molecular biology enabled a better knowledge of the molecular heterogeneity within BRAF mutant (BRAF^MT) CRCs, including high rate of overlapping with MSI-H status and detection of non-V600E mutations related to more favorable behavior. Treatment armamentarium has been rapidly growing in this subgroup and includes targeted combinations and immunotherapy for concomitant MSI-H patients, thereby making BRAF^MT mCRC an innovative model for precision oncology. Nevertheless, duration of responses to targeted strategies remains unsatisfactory due to the development of secondary resistance, which is currently the field of major clinical research on BRAF^MT mCRC. This review explores the molecular, clinical and therapeutic landscape of BRAF^MT mCRC as well as an update on current treatment strategies and future perspectives in light of the heterogeneity of BRAF-mutated disease. Furthermore, a novel treatment algorithm for BRAF^MT mCRC will be proposed.

Multigene Panel Sequencing Reveals Cancer-Specific and Common Somatic Mutations in Colorectal Cancer Patients: An Egyptian Experience

This study aims at identifying common pathogenic somatic mutations at different stages of colorectal carcinogenesis in Egyptian patients. Our cohort included colonoscopic biopsies collected from 120 patients: 20 biopsies from patients with inflammatory bowel disease, 38 from colonic polyp patients, and 62 from patients with colorectal cancer. On top of this, the cohort included 20 biopsies from patients with non-specific mild to moderated colitis. Targeted DNA sequencing using a customized gene panel of 96 colorectal related genes running on the Ion Torrent NGS technology was used to process the samples. Our results revealed that 69% of all cases harbored at least one somatic mutation. Fifty-seven genes were found to carry 232 somatic non-synonymous variants. The most frequently pathogenic somatic mutations were localized in TP53, APC, KRAS, and PIK3CA. In total, 16 somatic mutations were detected in the CRC group and in either the IBD or CP group. In addition, our data showed that 51% of total somatic variants were CRC-specific variants. The average number of CRC-specific variants per sample is 2.4. The top genes carrying CRC-specific mutations are APC, TP53, PIK3CA, FBXW7, ATM, and SMAD4. It seems obvious that TP53 and APC genes were the most affected genes with somatic mutations in all groups. Of interest, 85% and 28% of the APC and TP53 deleterious somatic mutations were located in Exon 14 and Exon 3, respectively. Besides, 37% and 28% of the total somatic mutations identified in APC and TP53 were CRC-specific variants, respectively. Moreover, we identified that, in 29 somatic mutations in 21 genes, their association with CRC patients was unprecedented. Ten detected variants were likely to be novel: six in PIK3CA and four variants in FBXW7. The detected P53, Wnt/βcatenin, Angiogenesis, EGFR, TGF-β and Interleukin signaling pathways were the most altered pathways in 22%, 16%, 12%, 10%, 9% and 9% of the CRC patients, respectively. These results would contribute to a better understanding of the colorectal cancer and in introducing personalized therapies for Egyptian CRC patients.

Regulation of LncRNAs in Melanoma and Their Functional Roles in the Metastatic Process

Long non-coding RNAs (lncRNAs) are key regulators of numerous intracellular processes leading to tumorigenesis. They are frequently deregulated in cancer, functioning as oncogenes or tumor suppressors. As they act through multiple mechanisms, it is not surprising that they may exert dual functions in the same tumor. In melanoma, a highly invasive and metastatic tumor with the propensity to rapidly develop drug resistance, lncRNAs play different roles in: (i) guiding the phenotype switch and leading to metastasis formation; (ii) predicting the response of melanoma patients to immunotherapy; (iii) triggering adaptive responses to therapy and acquisition of drug resistance phenotypes. In this review we summarize the most recent findings on the lncRNAs involved in melanoma growth and spreading to distant sites, focusing on their role as biomarkers for disease diagnosis and patient prognosis, or targets for novel therapeutic approaches.

New Approaches with Precision Medicine in Adult Brain Tumors

Primary central nervous system (CNS) tumors represent a heterogenous group of tumors. The 2021 fifth edition of the WHO Classification of Tumors of the CNS emphasizes the advanced role of molecular diagnostics with routine implementation of molecular biomarkers in addition to histologic features in the classification of CNS tumors. Thus, novel diagnostic methods such as DNA methylome profiling are increasingly used to provide a more precise diagnostic work-up of CNS tumors. In addition to these diagnostic precision medicine advantages, molecular alterations are also addressed therapeutically with targeted therapies. Like in other tumor entities, precision medicine has therefore also arrived in the treatment of CNS malignancies as the application of targeted therapies has shown promising response rates. Nevertheless, large prospective studies are currently missing as most targeted therapies were evaluated in single arm, basket, or platform trials. In this review, we focus on the current evidence of precision medicine in the treatment of primary CNS tumors in adults. We outline the pathogenic background and prevalence of the most frequent targetable genetic alterations and summarize the existing evidence of precision medicine approaches for the treatment of primary CNS tumors.

The Genomics of Hairy Cell Leukaemia and Splenic Diffuse Red Pulp Lymphoma

Classical hairy cell leukaemia (HCLc), its variant form (HCLv), and splenic diffuse red pulp lymphoma (SDRPL) constitute a subset of relatively indolent B cell tumours, with low incidence rates of high-grade transformations, which primarily involve the spleen and bone marrow and are usually associated with circulating tumour cells characterised by villous or irregular cytoplasmic borders. The primary aim of this review is to summarise their cytogenetic, genomic, immunogenetic, and epigenetic features, with a particular focus on the clonal BRAFV600E mutation, present in most cases currently diagnosed with HCLc. We then reflect on their cell of origin and pathogenesis as well as present the clinical implications of improved biological understanding, extending from diagnosis to prognosis assessment and therapy response.

The Molecular Pathology of Odontogenic Tumors: Expanding the Spectrum of MAPK Pathway Driven Tumors

Odontogenic tumors comprise a heterogeneous group of lesions that arise from the odontogenic apparatus and their remnants. Although the etiopathogenesis of most odontogenic tumors remains unclear, there have been some advances, recently, in the understanding of the genetic basis of specific odontogenic tumors. The mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPK/ERK) pathway is intimately involved in the regulation of important cellular functions, and it is commonly deregulated in several human neoplasms. Molecular analysis performed by different techniques, including direct sequencing, next-generation sequencing, and allele-specific qPCR, have uncovered mutations in genes related to the oncogenic MAPK/ERK signaling pathway in odontogenic tumors. Genetic mutations in this pathway genes have been reported in epithelial and mixed odontogenic tumors, in addition to odontogenic carcinomas and sarcomas. Notably, B-Raf proto-oncogene serine/threonine kinase (BRAF) and KRAS proto-oncogene GTPase (KRAS) pathogenic mutations have been reported in a high proportion of ameloblastomas and adenomatoid odontogenic tumors, respectively. In line with the reports about other neoplasms that harbor a malignant counterpart, the frequency of BRAF p.V600E mutation is higher in ameloblastoma (64% in conventional, 81% in unicystic, and 63% in peripheral) than in ameloblastic carcinoma (35%). The objective of this study was to review MAPK/ERK genetic mutations in benign and malignant odontogenic tumors. Additionally, such genetic alterations were discussed in the context of tumorigenesis, clinical behavior, classification, and future perspectives regarding therapeutic approaches.

Triple-Regimen of Vemurafenib, Irinotecan, and Cetuximab for the Treatment of BRAFV600E-Mutant CRC: A Case Report and Review

Mutation of the BRAF proto-oncogene is found in approximately 10% of colorectal cancers (CRC), with much of the mutation conferred by a V600E mutation. Unlike other CRC subtypes, BRAF-mutant CRC have had relatively limited response to conventional therapies and overall poor survival. We present the case of a 75-year-old man with severe nonischemic cardiomyopathy on a LifeVest who was found to have a transverse colonic mass with widespread hepatic metastatic disease and was subsequently found to have BRAF^V600E-mutant CRC (MSI High/dMMR). After a failed therapy with FOLFOX and pembrolizumab, the patient was started on a regimen of vemurafenib, irinotecan, and cetuximab (VIC) based on the SWOG 1406 trial which had shown improved progression-free survival and response rate for the treatment of BRAF^V600E-mutant metastatic CRC. After 40 cycles of VIC, the patient attained complete response and is in remission off chemotherapy with significant improvement. This case highlights the effectiveness of the triple-regimen of vemurafenib, irinotecan, and cetuximab as a treatment option for BRAF^V600E-mutant CRC, which is a treatment regimen based on the SWOG 1406 trial, and also demonstrates the synergistic role of BRAF^V600E inhibitors and EGFR inhibitors in the treatment of BRAF^V600E-mutant CRC.

Precise Characterization of Genetic Interactions in Cancer via Molecular Network Refining Processes

Genetic interactions (GIs), such as the synthetic lethal interaction, are promising therapeutic targets in precision medicine. However, despite extensive efforts to characterize GIs by large-scale perturbation screening, considerable false positives have been reported in multiple studies. We propose a new computational approach for improved precision in GI identification by applying constraints that consider actual biological phenomena. In this study, GIs were characterized by assessing mutation, loss of function, and expression profiles in the DEPMAP database. The expression profiles were used to exclude loss-of-function data for nonexpressed genes in GI characterization. More importantly, the characterized GIs were refined based on Kyoto Encyclopedia of Genes and Genomes (KEGG) or protein–protein interaction (PPI) networks, under the assumption that genes genetically interacting with a certain mutated gene are adjacent in the networks. As a result, the initial GIs characterized with CRISPR and RNAi screenings were refined to 65 and 23 GIs based on KEGG networks and to 183 and 142 GIs based on PPI networks. The evaluation of refined GIs showed improved precision with respect to known synthetic lethal interactions. The refining process also yielded a synthetic partner network (SPN) for each mutated gene, which provides insight into therapeutic strategies for the mutated genes; specifically, exploring the SPN of mutated BRAF revealed ELAVL1 as a potential target for treating BRAF-mutated cancer, as validated by previous research. We expect that this work will advance cancer therapeutic research.

Yeast as a Tool to Understand the Significance of Human Disease-Associated Gene Variants

At present, the great challenge in human genetics is to provide significance to the growing amount of human disease-associated gene variants identified by next generation DNA sequencing technologies. Increasing evidences suggest that model organisms are of pivotal importance to addressing this issue. Due to its genetic tractability, the yeast Saccharomyces cerevisiae represents a valuable model organism for understanding human genetic variability. In the present review, we show how S. cerevisiae has been used to study variants of genes involved in different diseases and in different pathways, highlighting the versatility of this model organism.

Precision oncology in metastatic colorectal cancer - from biology to medicine

Remarkable progress has been made in the development of biomarker-driven targeted therapies for patients with multiple cancer types, including melanoma, breast and lung tumours, although precision oncology for patients with colorectal cancer (CRC) continues to lag behind. Nonetheless, the availability of patient-derived CRC models coupled with in vitro and in vivo pharmacological and functional analyses over the past decade has finally led to advances in the field. Gene-specific alterations are not the only determinants that can successfully direct the use of targeted therapy. Indeed, successful inhibition of BRAF or KRAS in metastatic CRCs driven by activating mutations in these genes requires combinations of drugs that inhibit the mutant protein while at the same time restraining adaptive resistance via CRC-specific EGFR-mediated feedback loops. The emerging paradigm is, therefore, that the intrinsic biology of CRC cells must be considered alongside the molecular profiles of individual tumours in order to successfully personalize treatment. In this Review, we outline how preclinical studies based on patient-derived models have informed the design of practice-changing clinical trials. The integration of these experiences into a common framework will reshape the future design of biology-informed clinical trials in this field.

Current therapy of advanced colorectal cancer according to RAS/RAF mutational status

Colorectal cancer is a clinically and molecularly heterogeneous disease. Currently, extended RAS and BRAF mutation testing is obligatory in routine clinical practice before starting any treatment in the metastatic setting. Treatment decision making also includes assessment of the clinical condition of the patient, definition of the treatment goal, and consideration of the primary tumor site. Biological treatment is part of the first-line drug combination unless contraindicated. Mutational status is significantly associated with the outcome of patients and is strongly predictive for anti-EGFR-targeted therapy. The prognosis of RAS mutant CRC is clearly inferior to wild-type cases. RAS remains an elusive target, and specific treatment options are not yet available. Recently, promising results of a direct KRAS G12C inhibitor have been reported; however, further confirmation is needed. The biomarker landscape in mCRC is evolving; new promising markers are awaited with the chance of more precise targeted treatment.

Performance of capecitabine in novel combination therapies in colorectal cancer

Colorectal cancer is one of the most common cancers throughout the world, and no definitive cure has ever been found. Perhaps a new insight into the effectiveness of chemotherapy drugs could help better treat patients. Targeted therapies have significantly improved the median overall survival of colorectal cancer patients. One of the standard chemotherapy regimens used for colorectal cancer is capecitabine, which is important in monotherapy and combination therapies. Capecitabine, with other chemotherapeutic agents (irinotecan, oxaliplatin, perifosine, 17-allylamino-17-demethoxygeldanamycin, aspirin, celecoxib, statins, quinacrine, inositol hexaphosphate and inositol, cystine/theanine, curcumin, and isorhamnetin), and biological ones (antibodies) plays an important role in the inhibition of some signaling pathways, increasing survival, reducing tumor growth and side effects of capecitabine. However, some drugs, such as proton pump inhibitors, are negatively related to capecitabine; therefore, the purpose of this work is to review and discuss the performance of capecitabine combination therapies in colorectal cancer.

Many Distinct Ways Lead to Drug Resistance in BRAF- and NRAS-Mutated Melanomas

Advanced melanoma is a relentless tumor with a high metastatic potential. The combat of melanoma by using the targeted therapy is impeded because several major driver mutations fuel its growth (predominantly BRAF and NRAS). Both these mutated oncogenes strongly activate the MAPK (MEK/ERK) pathway. Therefore, specific inhibitors of these oncoproteins or MAPK pathway components or their combination have been used for tumor eradication. After a good initial response, resistant cells develop almost universally and need the drug for further expansion. Multiple mechanisms, sometimes very distant from the MAPK pathway, are responsible for the development of resistance. Here, we review many of the mechanisms causing resistance and leading to the dismal final outcome of mutated BRAF and NRAS therapy. Very heterogeneous events lead to drug resistance. Due to this, each individual mechanism would be in fact needed to be determined for a personalized therapy to treat patients more efficiently and causally according to molecular findings. This procedure is practically impossible in the clinic. Other approaches are therefore needed, such as combined treatment with more drugs simultaneously from the beginning of the therapy. This could eradicate tumor cells more rapidly and greatly diminish the possibility of emerging mechanisms that allow the evolution of drug resistance.

ddPCR Analysis Reveals BRAF V600E Mutations Are Infrequent in Isolated Pituitary Langerhans Cell Histiocytosis Patients

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia with a highly variable clinical presentation affecting people of all ages. Mutations in BRAF V600E are the most identifiable molecular alteration in LCH although its incidence in pediatric patients with isolated pituitary stalk involvement is not well described. Pediatric patients with LCH and isolated pituitary stalk involvement typically present with central diabetes insipidus. Diagnosis requires a transcranial biopsy which often yields scant tissue. We sought to determine the prevalence of BRAF V600E mutations in patients with isolated pituitary stalk LCH using digital droplet polymerase chain reaction because this method requires minimal tumor DNA. We identified 8 patients with isolated pituitary stalk thickening who underwent a biopsy at Children's Hospital Colorado from January 2001 to December 2019, as well as 6 patients with systemic LCH diagnosed by biopsy in the same period as a comparison. Only one out of the 8 patients with isolated thickened pituitary stalk was found to have a detectable BRAF V600E mutation. Five out of the 6 patients with systemic LCH had a detectable BRAF V600E mutation. In our series, BRAF V600E mutations are rare in pediatric patients with LCH and isolated pituitary stalk involvement.

Design and synthesis of 4-anilinoquinazolines as Raf kinase inhibitors. Part 1. Selective B-Raf/B-RafV600E and potent EGFR/VEGFR2 inhibitory 4-(3-hydroxyanilino)-6-(1H-1,2,3-triazol-4-yl)quinazolines

This paper presents the design and synthesis of 4-(3-hydroxyanilino)-6-(1H-1,2,3-triazol-4-yl)quinazolines of scaffold 9 as selective B-Raf/B-Raf^V600E and potent EGFR/VEGFR2 kinase inhibitors. Total 14 compounds of scaffold 9 having different side chains at the triazolyl group with/without fluoro substituents at the anilino group were synthesized and investigated. Among them, 9m with a 2-carbamoylethyl side chain and C-4'/C-6' difluoro substituents was the most potent, which selectively inhibited B-Raf (IC₅₀: 57 nM) and B-Raf^V600E (IC₅₀: 51 nM) over C-Raf (IC₅₀: 1.0 μM). Compound 9m also actively inhibited EGFR (IC₅₀: 73 nM) and VEGFR2 (IC₅₀: 7.0 nM) but not EGFR^T790M and PDGFR-β (IC₅₀: >10 μM). Despite having good potency for B-Raf and B-Raf^V600E in the enzymatic assays, 9m was less active to inhibit melanoma A375 cells which proliferate due to constitutively activated B-Raf^600E. The inferior activity of 9m for A375 was similar to that of sorafenib (6), suggesting that 9m might bind to the inactive conformations of B-Raf and B-Raf^V600E. Docking simulations could thus be performed to reveal the binding poses of 9m in B-Raf, B-Raf^V600E, and VEGFR2 kinases.

Exploring the Anti-Cancer Mechanism of Novel 3,4'-Substituted Diaryl Guanidinium Derivatives

We previously identified a guanidinium-based lead compound that inhibited BRAF through a hypothetic type-III allosteric mechanism. Considering the pharmacophore identified in this lead compound (i.e., “lipophilic group”, “di-substituted guanidine”, “phenylguanidine polar end”), several modifications were investigated to improve its cytotoxicity in different cancer cell lines. Thus, several lipophilic groups were explored, the di-substituted guanidine was replaced by a secondary amine and the phenyl ring in the polar end was substituted by a pyridine. In a structure-based design approach, four representative derivatives were docked into an in-house model of an active triphosphate-containing BRAF protein, and the interactions established were analysed. Based on these computational studies, a variety of derivatives was synthesized, and their predicted drug-like properties calculated. Next, the effect on cell viability of these compounds was assessed in cell line models of promyelocytic leukaemia and breast, cervical and colorectal carcinomas. The potential of a selection of these compounds as apoptotic agents was assessed by screening in the promyelocytic leukaemia cell line HL-60. The toxicity against non-tumorigenic epithelial MCF10A cells was also investigated. These studies allowed for several structure-activity relationships to be derived. Investigations on the mechanism of action of representative compounds suggest a divergent effect on inhibition of the MAPK/ERK signalling pathway.

[Aging: A matter of DNA damage, nuclear envelope alterations and inflammation?]

The accumulation of senescent cells accompanies organismal aging. Senescent cells produce an inflammatory microenvironment that is conducive to the development of many age-related diseases. Here we describe the different situations leading to cellular senescence and show that these situations are frequently associated with DNA damage. We also discuss the intimate link between cell aging and perturbations in the nuclear envelope, namely in nuclear lamins, as seen in progeroid syndromes. Finally, we present evidence that these alterations are associated with DNA repair defects, the persistence of DNA damage, and an inflammatory phenotype.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is caused by clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in lesions that leads to a spectrum of organ involvement and dysfunction. The pathogenic cells are defined by constitutive activation of the MAPK signaling pathway. Treatment of LCH is risk-adapted: patients with single lesions may respond well to local treatment, whereas patients with multisystem disease require systemic therapy. Although survival rates for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 20%. Despite progress made in the treatment of LCH, disease reactivation rates remain above 30%, and standard second-line treatment is yet to be established. Treatment failure is associated with increased risks for death and long-term morbidity, including LCH-associated neurodegeneration. Early case series report promising clinical responses in patients with relapsed and refractory LCH treated with BRAF or MEK inhibitors, although potential for this strategy to achieve cure remains uncertain.

Cyclic adenosine monophosphate (cAMP) signaling in melanocyte pigmentation and melanomagenesis

The second messenger cyclic adenosine monophosphate (cAMP) regulates numerous functions in both benign melanocytes and melanoma cells. cAMP is generated from two distinct sources, transmembrane and soluble adenylyl cyclases (tmAC and sAC, respectively), and is degraded by a family of proteins called phosphodiesterases (PDEs). cAMP signaling can be regulated in many different ways and can lead to varied effects in melanocytes. It was recently revealed that distinct cAMP signaling pathways regulate pigmentation by either altering pigment gene expression or the pH of melanosomes. In the context of melanoma, many studies report seemingly contradictory roles for cAMP in tumorigenesis. For example, cAMP signaling has been implicated in both cancer promotion and suppression, as well as both therapy resistance and sensitization. This conundrum in the field may be explained by the fact that cAMP signals in discrete microdomains and each microdomain can mediate differential cellular functions. Here, we review the role of cAMP signaling microdomains in benign melanocyte biology, focusing on pigmentation, and in melanomagenesis.

BRAF mutations in KIT/PDGFRA positive gastrointestinal stromal tumours (GISTs): Is their frequency underestimated?

BRAF V600E mutations in GISTs are considered to be one of the mutational events in KIT/PDGFRA negative or positive GISTs, respectively. BRAF mutated GISTs usually do not respond to imatinib treatment, even more GISTs with imatinib sensitive KIT mutation. However, they are almost phenotypically and morphologically identical with KIT/PDGFRA positive GISTs. In general, due to the small number of BRAF mutations in GIST and because of the rarity of concomitant BRAF/KIT or BRAF/PDGFRA mutations, their frequency may be depreciated. The aim of this study was BRAF mutation detection in KIT/PDGFRA positive GISTs and their verification by other molecular methods. We applied the sensitive droplet digital PCR on 35 randomly selected KIT/PDGFRA positive GISTs to detect V600E mutations. We have established two criteria for the evaluation of samples: false positive rate (FPR) based on the negative controls; Limit of Detection (LoD) based on the serial dilution of positive control from RKO cell line harboring heterozygous V600E mutation in constant wild-type DNA background. Results from ddPCR were verified by other molecular methods: allele-specific PCR, dideoxysequencing, competitive allele-specific TaqMan PCR (castPCR). FPR was determined as 5 (∼4.4) positive droplets, and LoD was assessed to 3.4293 copies/μL what is the method sensitivity of 0.0162 %. We identified eight KIT/PDGFRA positive patients with concomitant V600E mutation. The five of them were in coexistence with KIT mutation and three with PDGFRA mutation. We also included the liver metastasis, but data from primary tumour were not available. We achieved the very high sensitivity of the ddPCR method for detecting BRAF mutation in GISTs to have importance from the point of view of therapy.

Cellular Senescence and Anti-Cancer Therapy

BACKGROUND

Cellular senescence is generally understood as a permanent cell cycle arrest stemming from different causes. The mechanism of cellular senescence-induced cell cycle arrest is complex, involving interactions between telomere shortening, inflammations and cellular stresses. In recent years, a growing number of studies have revealed that cellular senescence could mediate the cancer progression of neighboring cells, but this idea is controversial and contradictory evidence argues that cellular senescence also contributes to tumor suppression.

OBJECTIVE

Given that the complicated role of senescence in various physiological and pathological scenarios, we try to clarify the precise contribution role of cellular senescence to tumor progression.

METHODS

Search for the information in a large array of relevant articles to support our opinion.

RESULTS

We discuss the relatively widespread occurrence of cellular senescence in cancer treatment and identify the positive and negative side of senescence contributed to tumor progression.

CONCLUSION

We argue that the availability of pro-senescence therapy could represent as a promising regimen for managing cancer disease, particularly with regard to the poor clinical outcome obtained with other anticancer therapies.

Knockdown of angiopoietin-like 2 induces clearance of vascular endothelial senescent cells by apoptosis, promotes endothelial repair and slows atherogenesis in mice

Elimination of senescent cells (SnC) is anti-atherogenic, but the specific contribution of senescent vascular endothelial cells (EC) is unknown. We inactivated angiopoietin like-2 (angptl2), a marker of SnEC and a pro-atherogenic cytokine in LDLr^-/-, hApoB₁₀₀^+/+ atherosclerotic (ATX) mice. Three months after a single vascular delivery of a small hairpin (sh)Angptl2 in 3-month old ATX mice using an adeno-associated virus serotype 1 (AAV1), aortic atheroma plaque progression was slowed by 58% (p<0.0001). In the native aortic endothelium, angptl2 expression was decreased by 80%, in association with a reduced expression of p21, a cyclin-dependent kinase inhibitor overexpressed in growth-arrested SnC. Endothelial activation was reduced (lower Icam-1, Il-1β and Mcp-1 expression), decreasing monocyte Cd68 expression in the endothelium. One week post-injection, the ratio Bax/Bcl2 increased in the endothelium only, suggesting that angptl2⁺/p21⁺ SnEC were eliminated by apoptosis. Four weeks post-injection, the endothelial progenitor marker Cd34 increased, suggesting endothelial repair. In arteries of atherosclerotic patients, we observed a strong correlation between p21 and ANGPTL2 (r=0.727, p=0.0002) confirming the clinical significance of angptl2-associated senescence. Our data suggest that therapeutic down-regulation of vascular angptl2 leads to the clearance of SnEC by apoptosis, stimulates endothelial repair and reduces atherosclerosis.

BRAF Mutated Colorectal Cancer: New Treatment Approaches

Colon cancer is one of the most frequently diagnosed malignancies in adults, considering both its incidence and prevalence. Anatomically, the right colon is considered as being from the cecum to the splenic flexure, and the left colon is from the splenic flexure to the rectum. Sidedness is a surrogate of a wide spectrum of colorectal cancer (CRC) biology features (embryology, microbiome, methylation, microsatellite instability (MSI), BRAF, aging, KRAS, consensus molecular subtypes (CMS), etc.), which result in prognostic factors. Different molecular subtypes have been identified, according to genomic and transcriptomic criteria. A subgroup harboring a BRAF mutation has been described, and represents approximately 10% of the patients diagnosed with colon cancer. This subgroup has morphological, clinical, and therapeutic characteristics that differ substantially from patients who do not carry this genetic alteration. Unfortunately, there is no established standard of care for this particular cohort of patients. This manuscript aims to study the biology of this subgroup of colon cancer, to understand the current approach in clinical research.

BRAF mutation and its inhibitors in sarcoma treatment

The mitogen‐activated protein kinase (MAPK) signaling pathway plays a significant role in mediating cellular physiological activities, such as proliferation, differentiation, apoptosis, and senescence. This signaling pathway is composed of several major proto‐oncogenes of RAS/RAF/MEK/ERK, among which the BRAF proto‐oncogene, as one of the three members of the RAF family, has a higher mutation rate than ARAF and CRAF and has attracted extensive attention. Regarding the BRAF mutation, approximately 95% of BRAF mutations belong to the BRAF V600E mutation, which can enhance the expression of the MAPK signaling pathway and is thus related to the occurrence and development of various malignant tumors and has been successfully identified as a therapeutic target. Moreover, drug resistance to BRAF inhibitor treatment also appears to be an important issue. Considering the successful use of BRAF inhibitors in melanoma, we provide a brief overview of the BRAF mutations, including their basic structures and activation mechanisms, and the new classification method for BRAF mutations. Most importantly, we summarize the results of BRAF inhibitor treatment in different sarcomas. To overcome drug resistance to BRAF inhibitor treatment, we also outline the different mechanisms of drug resistance to BRAF inhibitor treatment and introduce the combination strategy of BRAF inhibitors with other targeted therapies.

New perspectives on the role of Drp1 isoforms in regulating mitochondrial pathophysiology

Mitochondria are dynamic organelles constantly undergoing fusion and fission. A concerted balance between the process of mitochondrial fusion and fission is required to maintain cellular health under different physiological conditions. Mutation and dysregulation of Drp1, the major driver of mitochondrial fission, has been associated with various neurological, oncological and cardiovascular disorders. Moreover, when subjected to pathological insults, mitochondria often undergo excessive fission, generating fragmented and dysfunctional mitochondria leading to cell death. Therefore, manipulating mitochondrial fission by targeting Drp1 has been an appealing therapeutic approach for cytoprotection. However, studies have been inconsistent. Studies employing Drp1 constructs representing alternate Drp1 isoforms, have demonstrated differing impacts of these isoforms on mitochondrial fission and cell death. Furthermore, there are distinct expression patterns of Drp1 isoforms in different tissues, suggesting idiosyncratic engagement in specific cellular functions. In this review, we will discuss these inherent variations among human Drp1 isoforms and how they could affect Drp1-mediated mitochondrial fission and cell death.

Characterization of glycolysis-related gene expression in malignant melanoma

Malignant melanoma exhibits a distinct metabolic phenotype with high glycolytic activity. Previously, we have shown that glucose transporter isoform 1 (GLUT1) favors growth and metastasis of malignant melanoma. In this study, we investigated the expression of GLUT1 and the further glycolysis-related genes hexokinase 1 and 2 (HK1, HK2), lactate dehydrogenase A (LDH-A) and monocarboxylate transporters 1 and 4 (MCT1, MCT4) in eleven human melanoma cell lines under normoxic and hypoxic conditions. Furthermore, a set of 25 human malignant melanoma tissue samples was analyzed. Under hypoxic conditions, we could observe a significant upregulation of hypoxia-inducible factor 1 alpha (HIF-1a) target genes GLUT1, HK2 and LDH-A, but not MCT4. While under normoxic conditions the expression of glycolysis-related genes showed no correlation with origin or BRAF mutation status, GLUT1 expression was significantly elevated in metastatic and BRAF-V600E mutated melanoma cell lines under hypoxic conditions. Furthermore, GLUT1 expression in human melanoma tissue samples correlated significantly with HK1, LDH-A and MCT1 expression, confirming a glycolytic phenotype. Notably, Cyclin D1 expression, which is used as a prognostic marker for the outcome of melanoma patients, as it is associated with proliferation and invasiveness of melanoma, significantly correlated with GLUT1, HK1, LDH-A and MCT1 expression. In summary, our findings provide further evidence that enhanced glycolytic activity in melanoma favors disease progression and is an attractive therapeutic target for this highly aggressive tumor.

Proteomic Analysis Reveals a Role for RSK in p120-catenin Phosphorylation and Melanoma Cell-Cell Adhesion

The RAS/mitogen-activated protein kinase (MAPK) signaling pathway regulates various biological functions, including cell survival, proliferation and migration. This pathway is frequently deregulated in cancer, including melanoma, which is the most aggressive form of skin cancer. RSK (p90 ribosomal S6 kinase) is a MAPK-activated protein kinase required for melanoma growth and proliferation, but relatively little is known about its function and the nature of its cellular partners. In this study, we used a proximity-based labeling approach to identify RSK proximity partners in cells. We identified many potential RSK-interacting proteins, including p120ctn (p120-catenin), which is an essential component of adherens junction (AJ). We found that RSK phosphorylates p120ctn on Ser320, which appears to be constitutively phosphorylated in melanoma cells. We also found that RSK inhibition increases melanoma cell-cell adhesion, suggesting that constitutive RAS/MAPK signaling negatively regulates AJ integrity. Together, our results indicate that RSK plays an important role in the regulation of melanoma cell-cell adhesion.

Immunohistochemical Investigation of Mutant BRAF V600E in Common Pigmented Skin Neoplasms, Study on a Sample of Iranian Patients

Background & Objective:

This study was designed for the first time for the detec- tion of mutant BRAF V600E and its correlation with clinicophathologic features in a sample of Iranian patients with pathologically proved pigmented skin neoplasms.

Methods:

82 paraffin-embedded blocks, including melanocytic nevi, malignant melanoma, Basel cell carcinoma, and squamous cell carcinoma were evaluated for BRAF V600E expression by immunohistochemistry in the patients admitted to Ibn Sina Hospital, in the city of Sari, Mazandaran province, North of Iran. The evaluation of immunohistochemical staining was performed by two of the authoring pathologists, and staining intensity was graded from negative (0), weak (1+), moderate (2+) to strong (3+). If twenty percent (or greater) of the tumor cells showed modest to strong cytoplasmic immunoreactivity (score 3+), the neoplasm was considered positive for this tumor marker.

Results:

Among 82 studied patients, 12 cases (60%) of the malignant melanoma group revealed a high intensity of immunostaining for BRAF V600E, while a signifi- cant expression of this marker did not occur in the other investigated skin neoplasm. A great relation between BRAF (V600E) expression and the histologic type of skin cancer was noted. No significant relationship with other parameters such as gender, age, and the grade differentiation of the non-melanoma skin cancer was found. BRAF V600E was weakly correlated with the Clark level of cutaneous malignant melanoma.

Conclusion:

This data provided further evidence for the strong role of the BRAF V600E mutation in the development of cutaneous malignant melanoma, compared to non-melanoma skin cancers in the North of Iran. We advised future studies to evaluate the beneficial effects of anti-BRAF V600E target therapy on the Iranian melanoma patient who harbors this marker by way of immunostaining tumor tissue.

STAT3 and STAT5 Activation in Solid Cancers

The Signal Transducer and Activator of Transcription (STAT)3 and 5 proteins are activated by many cytokine receptors to regulate specific gene expression and mitochondrial functions. Their role in cancer is largely context-dependent as they can both act as oncogenes and tumor suppressors. We review here the role of STAT3/5 activation in solid cancers and summarize their association with survival in cancer patients. The molecular mechanisms that underpin the oncogenic activity of STAT3/5 signaling include the regulation of genes that control cell cycle and cell death. However, recent advances also highlight the critical role of STAT3/5 target genes mediating inflammation and stemness. In addition, STAT3 mitochondrial functions are required for transformation. On the other hand, several tumor suppressor pathways act on or are activated by STAT3/5 signaling, including tyrosine phosphatases, the sumo ligase Protein Inhibitor of Activated STAT3 (PIAS3), the E3 ubiquitin ligase TATA Element Modulatory Factor/Androgen Receptor-Coactivator of 160 kDa (TMF/ARA160), the miRNAs miR-124 and miR-1181, the Protein of alternative reading frame 19 (p19ARF)/p53 pathway and the Suppressor of Cytokine Signaling 1 and 3 (SOCS1/3) proteins. Cancer mutations and epigenetic alterations may alter the balance between pro-oncogenic and tumor suppressor activities associated with STAT3/5 signaling, explaining their context-dependent association with tumor progression both in human cancers and animal models.

Off-label use of common predictive biomarkers in gastrointestinal malignancies: a critical appraisal

The use of immunohistochemistry (IHC) as a companion diagnostic is an increasingly important part of the case workup by pathologists and is often central to clinical decision making. New predictive molecular markers are constantly sought for to improve treatment stratification parallel to drug development. Unfortunately, official biomarker guidelines lag behind, and pathologists are often left hesitating when medical oncologists request off-labelled biomarker testing. We performed a literature review of five commonly requested off-label IHC predictive biomarkers in gastrointestinal tract (GIT) malignancies: HER2, mismatch repair (MMR), PD-L1, BRAF V600E and ROS1. We found that HER2 amplification is rare and poorly associated to IHC overexpression in extracolonic and extragastric GIT cancers; however in KRAS wild type colorectal cancers, which fail conventional treatment, HER2 IHC may be useful and should be considered. For MMR testing, more evidence is needed to recommend reflex testing in GIT cancers for treatment purposes. MMR testing should not be discouraged in patients considered for second line checkpoint inhibitor therapy. With the exception of gastric tumors, PD-L1 IHC is a weak predictor of checkpoint inhibitor response in the GIT and should be replaced by MMR in this context. BRAF inhibitors showed activity in BRAF V600E mutated cholangiocarcinomas and pancreatic carcinomas in non-first line settings. ROS1 translocation is extremely rare and poorly correlated to ROS1 IHC expression in the GIT; currently there is no role for ROS1 IHC testing in GIT cancers. Overall, the predictive biomarker literature has grown exponentially, and official guidelines need to be updated more regularly to support pathologists’ testing decisions.

Design and Synthesis of Type-IV Inhibitors of BRAF Kinase That Block Dimerization and Overcome Paradoxical MEK/ERK Activation

Despite the clinical success of BRAF inhibitors like vemurafenib in treating metastatic melanoma, resistance has emerged through "paradoxical MEK/ERK signaling" where transactivation of one protomer occurs as a result of drug inhibition of the other partner in the activated dimer. The importance of the dimerization interface in the signaling potential of wild-type BRAF in cells expressing oncogenic Ras has recently been demonstrated and proposed as a site of therapeutic intervention in targeting cancers resistant to adenosine triphosphate competitive drugs. The proof of concept for a structure-guided approach targeting the dimerization interface is described through the design and synthesis of macrocyclic peptides that bind with high affinity to BRAF and that block paradoxical signaling in malignant melanoma cells occurring through this drug target. The lead compounds identified are type-IV kinase inhibitors and represent an ideal framework for conversion into next-generation BRAF inhibitors through macrocyclic drug discovery.

The BRAF-inhibitor PLX4720 inhibits CXCL8 secretion in BRAFV600E mutated and normal thyroid cells: a further anti-cancer effect of BRAF-inhibitors

CXCL8 is a chemokine secreted by normal and thyroid cancer cells with proven tumor-promoting effects. The presence of BRAFV600E mutation is associated with a more aggressive clinical behavior and increased ability to secrete CXCL8 by papillary-thyroid-cancer cells. Aim of this study was to test the effect of the BRAF-inhibitor (PLX4720) on the basal and TNF-α-induced CXCL8 secretions in BRAFV600E mutated (BCPAP, 8305C, 8505C), in RET/PTC rearranged (TPC-1) thyroid-cancer-cell-lines and in normal-human-thyrocytes (NHT). Cells were incubated with increasing concentrations of PLX4720 alone or in combination with TNF-α for 24-hours. CXCL8 concentrations were measured in the cell supernatants. PLX4720 dose-dependently inhibited the basal and the TNF-α-induced CXCL8 secretions in BCPAP (F: 14.3, p < 0.0001 for basal and F: 12.29 p < 0.0001 for TNF-α), 8305C (F: 407.9 p < 0.0001 for basal and F: 5.76 p < 0.0001 for TNF-α) and 8505C (F:55.24 p < 0.0001 for basal and F: 42.85 p < 0.0001 for TNF-α). No effect was found in TPC-1 (F: 1.8, p = 0.134 for basal; F: 1.6, p = 0.178 for TNF-α). In NHT an inhibitory effect was found only at the highest concentration of PLX4720 (F: 13.13 p < 0.001 for basal and F: 2.5 p < 0.01 for TNF-α). Cell migration assays showed that PLX4720 reduced both basal and CXCL8-induced cell migration in BCPAP, 8305C, 8505C and NHT but not in TPC-1 cells. These results constitutes the first demonstration that PLX4720 is able to inhibit the secretion of CXCL8 in BRAFV600E mutated thyroid cancer cells indicating that, at least some, of the anti-tumor activities of PLX4720 could be exerted through a lowering of CXCL8 in the thyroid-cancer-microenvironment.

Synergistic Activity of Paclitaxel, Sorafenib, and Radiation Therapy in advanced Renal Cell Carcinoma and Breast Cancer

Advanced cancer has been shown to be associated with a higher percentage of epigenetic changes than with genetic mutations. Preclinical models have shown that the combination of paclitaxel, sorafenib, and radiation therapy (RT) plays a crucial role in renal cell carcinoma (RCC) and breast cancer. This study aimed to investigate the involvement of mitochondrial cytochrome c-dependent apoptosis in the mechanism of action of a combination of paclitaxel, sorafenib, and RT in RCC and breast cancer. RCC and breast cancer cell lines were exposed to paclitaxel and sorafenib alone or combined in the presence of radiation, and cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The synergistic anticancer effects of the combination therapy on cell cycle and intracellular signaling pathways were estimated using flow cytometry and immunoblot analysis. RCC and breast cancer cell line xenograft models were used to examine the antitumor activity in vivo. Our results suggest that paclitaxel, sorafenib, and RT synergistically decreased the viability of RCC and breast cancer cells and significantly induced their apoptosis, as shown by caspase-3 cleavage. Paclitaxel, sorafenib, and radiation cotreatment reduced antiapoptotic factor levels in these cells and, thereby, significantly reduced the tumor volume of RCC and breast cancer cell xenografts. The current study suggests that paclitaxel, sorafenib, and radiation cotreatment was more effective than cotreatment with paclitaxel or sorafenib and radiation. These findings may offer a new therapeutic approach to RCC and breast cancer.

Cell surface CD63 increased by up-regulated polylactosamine modification sensitizes human melanoma cells to the BRAF inhibitor PLX4032

The BRAF inhibitor PLX4032 is effective in treating BRAF-mutated melanoma; however, because drug resistance develops in most cases, it is critical to develop a new strategy for inhibiting drug-resistant melanoma growth. The melanoma-associated membrane glycoprotein CD63 is involved in cell proliferation and metastasis. Here, we found that cell surface CD63 suppresses the proliferation of human melanoma cells and PLX4032-resistant cells. Endogenous CD63 protein levels were negatively correlated with PLX4032 resistance of human melanoma cell lines. CD63 overexpression in these cells, in which endogenous CD63 levels are low, suppressed cell proliferation under PLX4032 treatment. The cell surface levels and average molecular mass of CD63 were increased with PLX4032 treatment because of the up-regulated polylactosamine modification caused by induced β1,3- N-acetylglucosaminyltransferase 2 expression, which is involved in polylactosamine synthesis. Forced cell surface localization of CD63 led to reduced melanoma cell proliferation without PLX4032 treatment. CD63 overexpression in PLX4032-resistant cells, in which CD63 levels were lower and cell surface polylactosamine levels were higher than those in parental cells, effectively suppressed proliferation. Our study shows the potential of CD63 to sensitize melanoma cells to PLX4032 and to reduce the proliferation of PLX4032-resistant cells.-Kudo, K., Yoneda, A., Sakiyama, D., Kojima, K., Miyaji, T., Yamazaki, M., Yaita, S., Hyodo, T., Satow, R., Fukami, K. Cell surface CD63 increased by up-regulated polylactosamine modification sensitizes human melanoma cells to the BRAF inhibitor PLX4032.

Papilloma of the Fallopian Tube: A Rare Gynecologic Neoplasm Harboring a BRAF (c.1799T>A) Mutation (V600E)

Papillomas of the fallopian tube are exceedingly rare benign tumors, and only very few cases have been reported in the literature. Clinically, they may present as a mass lesion or occur without symptoms. Histomorphologically, they are papillary tumors covered by nonatypical epithelium with occasional ciliated or goblet cells growing in the lumen, and they are most frequently located in the infundibular region of the fallopian tube. They require a number of differential diagnostic evaluations and can be mistaken for either other benign tumors or malignant neoplasms. Because of their rare occurrence, molecular data about this entity have been lacking so far. Herein, a case of a papilloma with a BRAF (c.1799T>A) mutation (V600E) in a 45-yr-old woman with tumor-like dilation of the fallopian tube is presented.

[Senescence and cancer: double-dealing]

When ageing, cells profoundly reprogram to enter a state called senescence. Although the link between senescence and cancer is well established, the nature of this link remains unclear and debated. We will describe in this article the properties of senescent cells and make clear on how they could promote or oppose to cancer initiation and progression. We will also consider senescence as a response to classical anti-cancer therapies and discuss how to take advantage of senescence to improve the efficacy of these therapies while decreasing their toxicity.

Targeted drug delivery to melanoma

Melanoma derived from melanocytes is the most aggressive genre of skin cancer. Although the considerable advancement in the study of human cancer biology and drug discovery, most advanced melanoma patients are inevitably unable to be cured. With the emergence of nanotechnology, the use of nano-carriers is widely expected to alter the landscape of melanoma treatment. In this review, we will discuss melanoma biology, current treatment options, mechanisms behind drug resistance, and nano-based solutions for effective anti-cancer therapy, followed by challenges and perspectives in both pre-clinical and clinical settings.