Pathways In Cancer Development Research Articles

Crosstalk between Phosphoinositide 3-kinase/Akt signaling pathway with DNA damage response and oxidative stress in cancer.

The phosphatidylinositol 3-kinases (PI3K)/Akt signaling pathway is one of the well-characterized and most important signaling pathways activated in response to DNA damage. This review discusses the most recent discoveries on the involvement of PI3K/Akt signaling pathway in cancer development, as well as stimulation of some important signaling networks involved in the maintenance of cellular homeostasis upon DNA damage, with an exploration of how PI3K/Akt signaling pathway contributes to the regulation of modulators and effectors underlying DNA damage response, the intricate, protein-based signal transduction network, which decides between cell cycle arrest, DNA repair, and apoptosis, the elimination of irreparably damaged cells to maintain homeostasis. The review continues by looking at the interplay between cell cycle checkpoints, checking the repair of damage inflicted to the DNA before entering DNA replication to facilitate DNA synthesis, and PI3K/Akt signaling pathway. We then investigate the challenges the cells overcome to ameliorate damages induced by oxidative activities, for example, the recruitment of many pathways and factors to maintain integrity and hemostasis. Finally, the review provides a discussion of how cells use the PI3K/Akt signaling pathway to regulate the balance between these networks.

Role of the cGAS-STING pathway in cancer development and oncotherapeutic approaches.

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway mediates anti-microbial innate immunity by inducing the production of type I interferons (IFNs) and inflammatory cytokines upon recognition of microbial DNA. Recent studies reveal that self-DNA from tumors and by-products of genomic instability also activates the cGAS-STING pathway and either promotes or inhibits tumor development. This has led to the development of cancer therapeutics using STING agonists alone and in combination with conventional cancer treatment or immune checkpoint targeting. On the other hand, for cancers lacking the cGAS-STING pathway and thus a regular innate immunity response, oncolytic virus therapy has been shown to have therapeutic potential. We here review and discuss the dichotomous roles of the cGAS-STING pathway in cancer development and therapeutic approaches.

Inhibitory Effects of Pulse Bioactive Compounds on Cancer Development Pathways.

Previous studies suggest that pulses may have the potential to protect against cancer development by inhibiting pathways that result in the development of cancer. These pathways include those that result in inflammation, DNA damage, cell proliferation, and metastasis. Other studies have demonstrated extracts from pulses have the capacity to induce apoptosis specifically in cancer cells. Compounds reported to be responsible for these activities have included phenolic compounds, proteins and short chain fatty acids. The majority of the studies have been undertaken using in vitro cell culture models, however, there are a small number of in vivo studies that support the hypothesis that pulse consumption may inhibit cancer development. This review highlights the potential benefit of a diet rich in pulse bioactive compounds by exploring the anti-cancer properties of its polyphenols, proteins and short chain fatty acids.

Abstract 4513: Notch inhibitors relieve growth suppression by TGF-β and promote growth and metastasis of triple-negative breast cancers

Abstract The paradoxical behavior of Notch1 and transforming growth factor-beta (TGF-β) is puzzling as they were shown to have both tumor-suppressive and tumor-promoting activities. We addressed the interaction between these two signaling pathways in cancer development and progression in a systematic way. Towards this goal, we utilized primary human mammary epithelial cells (HMEC) and various triple-negative breast cancer (TNBC) cells and examined the molecular crosstalk between TGF-β1 and Notch signaling pathways using biochemical, molecular and cell biology techniques. First, we observed lower expression of Notch1 in most of the TNBC cells compared to normal cells. Most of these TNBC cells also overexpressed TMEPAI (transmembrane prostate androgen induced), which we previously showed switches TGF-β from tumor-suppressive to a tumor-promoting role in breast cancer. Surprisingly, treatment of TNBC with Notch inhibitors increased their growth rate both in the absence and presence of TGF-β, while Notch inhibitors relieved normal cells from TGF-β mediated growth suppression. Both normal and TNBC cells showed increased growth in the presence of Notch inhibitors with decreased TGF-β signaling activity. In fact, normal cells that express very low levels of TMEPAI both at mRNA and protein levels, overexpressed TMEPAI in presence of various Notch inhibitors, suggesting that Notch1 negatively regulates TMEPAI expression. Correspondingly, knockdown of TMEPAI in TNBC cell lines showed increased expression of Notch1 and Jagged 1, suggesting a negative regulation of Notch1 by TMEPAI. In fact, TMEPAI, which binds to E3 ligases, promoted increased turnover of Notch1. In contrast to notch inhibitors, overexpression of active Notch1 in MDA-MB-231 cells inhibited tumor cell growth both in vitro and in vivo. Our results clearly suggest that a crosstalk between TGF-β and Notch1 signaling exists through TMEPAI. Importantly, these studies should be taken into consideration while contemplating the use of Notch inhibitors in triple-negative breast cancer therapy. Citation Format: Pothana Saikumar, Prajjal K. Singha, Srilakshmi Pandeswara, Manjeri A. Venkatachalam. Notch inhibitors relieve growth suppression by TGF-β and promote growth and metastasis of triple-negative breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4513.

Genetic inactivation of Nrf2 prevents clonal expansion of initiated cells in a nutritional model of rat hepatocarcinogenesis

Dysregulation of the Keap1-Nrf2 pathway has been observed in experimental and human tumors, suggesting possible roles of the pathway in cancer development. Herein, we examined whether Nrf2 (Nfe2l2) activation occurs at early steps of rat hepatocarcinogenesis, to assess critical contributions of Nrf2 to the onset of hepatocellular carcinoma (HCC). We used wild-type (WT) and Nrf2 knockout (Nrf2KO) rats treated with a single injection of diethylnitrosamine (DENA) followed by choline-devoid methionine-deficient (CMD) diet. This experimental model causes massive fatty liver and steatohepatitis with fibrosis and enables identification of early stages of hepatocarcinogenesis. We found that Nrf2 activation takes place in early preneoplastic lesions identified by the marker glutathione S-transferase placental form (GSTP). Nrf2 missense mutations, known to disrupt the Keap1-Nrf2 binding, were present in 65.7% of GSTP-positive foci. Nrf2KO rats were used to directly investigate whether Nrf2 is critical for initiation and/or clonal expansion of DENA-damaged hepatocytes. While Nrf2 genetic inactivation did not alter DENA-induced initiation, it led to increased liver injury and chronic compensatory hepatocyte regeneration when rats were fed a CMD diet. However, in spite of such a permissive environment, the livers of Nrf2KO rats did not display any preneoplastic lesion unlike those of WT rats. These results demonstrate that, in a model of hepatocarcinogenesis resembling human non-alcoholic fatty liver disease: i) Nrf2 is activated at early steps of the tumorigenic process and ii) Nrf2 is mandatory for the clonal expansion of initiated cells, indicating that Nrf2 is critical in the onset of HCC. Dysregulation of the Keap1-Nrf2 molecular pathway has been observed in human tumors. In a nutritional model of hepatocarcinogenesis, the protein Nrf2 is frequently mutated/activated at early steps of the tumorigenic process. Herein, we show that Nrf2 is mandatory for the development of preneoplastic lesions. These results suggest that Nrf2 has a critical role in the onset of hepatocellular carcinoma.

Integrated Genomic Analysis of the Ubiquitin Pathway across Cancer Types

Protein ubiquitination is a dynamic and reversible process of adding single ubiquitin molecules or various ubiquitin chains to target proteins. Here, using multidimensional omic data of 9,125 tumor samples across 33 cancer types from The Cancer Genome Atlas, we perform comprehensive molecular characterization of 929 ubiquitin-related genes and 95 deubiquitinase genes. Among them, we systematically identify top somatic driver candidates, including mutated FBXW7 with cancer-type-specific patterns and amplified MDM2 showing a mutually exclusive pattern with BRAF mutations. Ubiquitin pathway genes tend to be upregulated in cancer mediated by diverse mechanisms. By integrating pan-cancer multiomic data, we identify a group of tumor samples that exhibit worse prognosis. These samples are consistently associated with the upregulation of cell-cycle and DNA repair pathways, characterized by mutated TP53, MYC/TERT amplification, and APC/PTEN deletion. Our analysis highlights the importance of the ubiquitin pathway in cancer development and lays a foundation for developing relevant therapeutic strategies.

Targeting tumor hypoxia with stimulus-responsive nanocarriers in overcoming drug resistance and monitoring anticancer efficacy

Although existing nanomedicines have focused on the tumor microenvironment with the goal of improving the effectiveness of conventional chemotherapy, the penetration of a tumor’s core still represents a formidable barrier for existing drug delivery systems. Therefore, a novel multifunctional hypoxia-induced size-shrinkable nanoparticle has been designed to increase the penetration of drugs, nucleic acids, or probes into tumors. This cooperative strategy relies on three aspects: (i) the responsiveness of nanoparticles to hypoxia, which shrink when triggered by low oxygen concentrations; (ii) the core of a nanoparticle involves an internal cavity and strong positive charges on the surface to deliver both doxorubicin and siRNA; and (iii) a reactive oxygen species (ROS) probe is incorporated in the nanoparticle to monitor its preliminary therapeutic response in real time, which is expected to realize the enhanced efficacy together with the ability to self-monitor the anticancer activity. A more effective inhibition of tumor growth was observed in tumor-bearing zebrafish, demonstrating the feasibility of this cooperative strategy for in vivo applications. This research highlights a promising value in delivering drugs, nucleic acids, or probes to a tumor’s core for cancer imaging and treatment. Statement of SignificanceHypoxia-induced chemoresistance of tumor cells still represents a formidable barrier, as it is difficult for existing drug delivery systems to penetrate the tumor hypoxia core. This study involves the hypoxia-responsive size-shrinkable nanoparticle co-delivery of DOX and siRNA to enhance the penetration of DOX deep within tumors and subsequently disturb crucial pathways of cancer development induced by hypoxia and to improve sensitization to DOX chemotherapy. Furthermore, the nanopreparation can combine the ROS probe as a self-reporting nanopreparation to realize the function of real-time feedback efficacy, which has a good application prospect in the diagnosis and treatment of cancer.

Appraising the relevance of DNA copy number loss and gain in prostate cancer using whole genome DNA sequence data.

A variety of models have been proposed to explain regions of recurrent somatic copy number alteration (SCNA) in human cancer. Our study employs Whole Genome DNA Sequence (WGS) data from tumor samples (n = 103) to comprehensively assess the role of the Knudson two hit genetic model in SCNA generation in prostate cancer. 64 recurrent regions of loss and gain were detected, of which 28 were novel, including regions of loss with more than 15% frequency at Chr4p15.2-p15.1 (15.53%), Chr6q27 (16.50%) and Chr18q12.3 (17.48%). Comprehensive mutation screens of genes, lincRNA encoding sequences, control regions and conserved domains within SCNAs demonstrated that a two-hit genetic model was supported in only a minor proportion of recurrent SCNA losses examined (15/40). We found that recurrent breakpoints and regions of inversion often occur within Knudson model SCNAs, leading to the identification of ZNF292 as a target gene for the deletion at 6q14.3-q15 and NKX3.1 as a two-hit target at 8p21.3-p21.2. The importance of alterations of lincRNA sequences was illustrated by the identification of a novel mutational hotspot at the KCCAT42, FENDRR, CAT1886 and STCAT2 loci at the 16q23.1-q24.3 loss. Our data confirm that the burden of SCNAs is predictive of biochemical recurrence, define nine individual regions that are associated with relapse, and highlight the possible importance of ion channel and G-protein coupled-receptor (GPCR) pathways in cancer development. We concluded that a two-hit genetic model accounts for about one third of SCNA indicating that mechanisms, such haploinsufficiency and epigenetic inactivation, account for the remaining SCNA losses.

Abstract 3131: Ubiquitin ligases: a new target for RNAi therapy of hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third leading cause of cancer-related deaths in the world. HCC is a very aggressive cancer, resistant to all conventional chemotherapies and capable of acquiring resistance to Sorafenib, which is the only approved chemotherapeutic drug for HCC. This highlights the need to look for new therapeutic options and improve the survival of patients with advanced HCC. The N-end rule pathway is an emerging player in the field of cancer biology, because of its capacity to positively regulate many hallmarks of cancer including angiogenesis, cell proliferation, motility and survival. Therefore, the N-end rule pathway offers the potential to be a target for highly effective anti-tumor treatment. The aim of this study is to investigate the role of the N-end rule pathway in the context of hepatocellular carcinoma in vivo. We used siRNA-mediated RNA interference as the main approach for selective downregulation of the four N-end rule-dependent cognate ubiquitin ligases: UBR1, UBR2, UBR4 and UBR5. Initial screening of siRNAs was performed in Hepa 1-6 cells, followed by in vitro phenotyping using proliferation assays, migration assays, and TUNEL assays. The most potent siRNA against Ubr1, Ubr2, Ubr4 and Ubr5 were formulated into lipid nanoparticles (LNPs) and injected into mice in order to modulate the function of the N-end rule in vivo. We have confirmed that Ubr1, Ubr2, Ubr4 and Ubr5 are overexpressed in Hepa 1-6 cells and in mouse liver tumors, in comparison to normal liver. Upon transfection of siRNAs in Hepa 1-6 cells or injection of LNPs loaded with the same siRNAs into mice, we obtained successful down regulation of Ubr1, Ubr2, Ubr4 and Ubr5 both in vitro and in vivo (in the liver and in tumor tissue). We have also demonstrated that down regulation of these four Ubr proteins negatively affects cell migration and proliferation, and renders cells more susceptible to apoptosis. Bi-weekly injections of the LNPs in mice for a period up to 6 weeks efficiently downregulates the expression of Ubr1, Ubr2, Ubr4 and Ubr5 without any toxic effects. Indeed, we found no significant increase of ALT, AST or total bilirubin in the blood compared to controls. Considering that all four Ubrs are overexpressed in mouse liver tumors, and that the N-end rule plays a major role in many key pathways of cancer development, we expect that even a partial down regulation of this pathway will have prominent effects on tumor development and progression due to the suppression of tumor vascularization, cell proliferation and viability. Citation Format: Dominique Leboeuf, Timofei Zatsepin, Daniel G. Anderson, Konstantin Piatkov. Ubiquitin ligases: a new target for RNAi therapy of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3131. doi:10.1158/1538-7445.AM2017-3131

Role of JNK signaling in oral cancer: A mini review.

JNKs (c-Jun N-terminal kinases) belong to mitogen-activated protein kinases' family and become activated by several growth factors, stress, radiation, and other extracellular signals. In turn, JNK activation results in phosphorylation of downstream molecules involved in many normal cellular processes. Nevertheless, recent data have linked JNK signaling with several pathological conditions, including neurodegenerative diseases, inflammation, and cancer. The role of JNK in cancer remains controversial. Initially, JNK was thought to play a rather oncosuppressive role by mediating apoptosis in response to stress stimuli, inflammatory, or oncogenic signals. However, a number of studies have implicated JNK in malignant transformation and tumor growth. The contradictory functions of JNK in cancer may be due to the diversity of JNK upstream and downstream signaling and are under intensive investigation. This review summarizes current literature focusing on the significance of JNK pathway in cancer development and progression, particularly addressing its role in oral cancer. Understanding the complexity of JNK signaling has the potential to elucidate important molecular aspects of oral cancer, possibly leading to development of novel and individualized therapeutic strategies.

Investigation of the Association of HOTAIR Single Nucleotide Polymorphisms and Risk of Breast Cancer in an Iranian Population

Background: Long non coding RNAs (lncRNAs) are of functional non coding RNAs which have been shown to be involved in several important pathways in cancer development and progression. Among them is Hox transcript antisense intergenic RNA (HOTAIR) whose overexpression has been detected in several cancer types. In addition, its functional polymorphisms have been shown to be associated with breast cancer risk in certain populations. Objectives: The aim of the present study was to investigate the effects of three HOTAIR polymorphisms (rs12826786, rs1899663 and rs4759314) and their haplotypes on breast cancer risk in a sample of Iranian population. Methods: This study is a case-control study which consisted of 122 unrelated breast cancer patients from Hamadan University hospital and 200 normal females who were referred to a routine health survey in 2015. Genomic DNA was extracted from blood samples of all participants using the standard salting out method. Tetra-primer ARMS-PCR method was used for analyses of rs12826786, rs1899663, and rs4759314 genotypes. Comparison of genotype and allele frequency between the breast cancer patients and the control groupwas performed using Pearson chi-square test considering odds ratio (OR)and95 confidence intervals (CI) for calculation of the relative risk. Haplotype frequencies for HOTAIR were calculated using SNPStats online program. Results: No significant difference has been found in allele and genotype frequencies of polymorphisms between case and control groups. Furthermore, no specific HOTAIR haplotype was shown to be associated with breast cancer risk in the analyzed population. Conclusions: These polymorphisms do not seem to be associated with breast cancer risk in this population. However, further research is needed to evaluate the results of the present study in larger patient samples. © 2017, International Journal of Cancer Management.

Developmental pathways associated with cancer metastasis: Notch, Wnt, and Hedgehog.

Master developmental pathways, such as Notch, Wnt, and Hedgehog, are signaling systems that control proliferation, cell death, motility, migration, and stemness. These systems are not only commonly activated in many solid tumors, where they drive or contribute to cancer initiation, but also in primary and metastatic tumor development. The reactivation of developmental pathways in cancer stroma favors the development of cancer stem cells and allows their maintenance, indicating these signaling pathways as particularly attractive targets for efficient anticancer therapies, especially in advanced primary tumors and metastatic cancers. Metastasis is the worst feature of cancer development. This feature results from a cascade of events emerging from the hijacking of epithelial-mesenchymal transition, angiogenesis, migration, and invasion by transforming cells and is associated with poor survival, drug resistance, and tumor relapse. In the present review, we summarize and discuss experimental data suggesting pivotal roles for developmental pathways in cancer development and metastasis, considering the therapeutic potential. Emerging targeted antimetastatic therapies based on Notch, Wnt, and Hedgehog pathways are also discussed.

PP75. DROSOPHILA MELANOGASTER AS A MODEL ORGANISM TO STUDY GLIOMA: LOCATION AND IDENTIFICATION OF FOLLISTATIN

Gliomas are the most common, malignant brain tumour found in the central nervous system. The main characteristics of gliomas is their rapid proliferation, resistance to current chemotherapies and their ability to infiltrate the brain. Brain tumours have a low survival rate due to the lack of available treatments. In the UK between 2010 and 2011, the survival rate was 14% for 10 or more year. The mortality rates for malignant brain and CNS tumours have increased by up to 24% in the UK between 1970 and 2012. As there is difficulty obtaining glioma samples, it is important to identify a suitable model organism. The main signalling pathways seen to be activated in human glioma development are the epithelial growth factor receptor (EGFR) and phosphatidylinositol-3 kinase (PI3K) pathways. The homologous EFGR and PI3K pathways have been studied greatly in drosophila, and show that there must be co-activation of the EGFR and PI3K pathways for cancer development to occur; leading to an increase in glial cell numbers by 50-100x fold. Follistatin is a protein which has been identified as a biomarker in malignant gliomas; by comparing normal serum to glioma serum it has shown that there is an overexpression of follistatin. Gliomas can be replicated in drosophila as there has been a high level of homology identified in human diseased states and in neural development. Follistatin studies have shown it has important roles in development and differentiation of tissues and organs. It acts as an inhibitor, binding to activin, bone morphogenetic proteins and other proteins which can be found in vertebrates. Follistatin has been identified within a number of different cancer types (such as prostate and ovarian), and plays an important role in cancer metastasis and angiogenesis. Serum studies have revealed follistatin is present in the early stages of cancer development; however the location and role of follistatin in cancer development has not been identified. Drosophila contain a homolog of follistatin, which will allow studies of follistatin in cancer within drosophila. By using drosophila as a model organism it will allow the location of follistatin and its involvement in glioma development to be identified. Immunohistochemistry is used to identify the location and distribution of a protein within a tissue or an organ. It is commonly used to identify which proteins are present in specific types of cancer. Follistatin has been identified to play a role in the early stages of glioma development. Therefore by using immunohistochemistry follistatin can be identified throughout the different stages of glioma development and possibly identify its role in this development. The aim of the research is to identify and locate the protein follistatin in drosophila by using immunohistochemistry. Using different larval instar stages, this will identify the distribution of follistatin in different stages of neural development. The hypothesis would be that follistatin is involved in the early stages of glial development and the distribution is important in glioma development compared to normal neural development.

The crosstalk between microRNAs and the Wnt/β-catenin signaling pathway in cancer.

Mounting evidence has indicated microRNA (miR) dysregulation and the Wnt/β-catenin signaling pathway jointly drive carcinogenesis, cancer metastasis, and drug-resistance. The current review will focus on the role of the crosstalk between miRs and the Wnt/β-catenin signaling pathway in cancer development. MiRs were found to activate or inhibit the canonical Wnt pathway at various steps. On the other hand, Wnt activation increases expression of miR by directly binding to its promoter and activating transcription. Moreover, there are mutual feedback loops between some miRs and the Wnt/β-catenin signaling pathway. Clinical trials of miR-based therapeutic agents are investigated for solid and hematological tumors, however, challenges concerning low bioavailability and possible side effects must be overcome before the final clinical application. This review will describe current understanding of miR crosstalk with the Wnt/β-catenin signaling cascade. Better understanding of the regulatory network will provide insight into miR-based therapeutic development.

Colorectal Cancer: Descriptive Analysis Comparing a Native African Population to an African American Population

Introduction: The ACG recommends colorectal cancer (CRC) screening at an earlier age (45 years) in the African-American (AA) population. However, there is limited data comparing the African-American population to the native African population. Therefore, we compared the trends of CRC in a native African (NA) and African-American populations using the SEER database and the local cancer disease hospital (CDH) registry. Methods: A retrospective analysis of the CDH database in Zambia, Southern Africa and SEER database. All medical records of patients with CRC were retrieved and manually reviewed. A data collection tool and master sheet code created a priori were used. We extracted gender, age, time of presentation, mode of diagnosis, stage at diagnosis, treatment and outcome. For the African-American population, we extracted CRC data from the SEER database. Data was analyzed using SAS. Descriptive statistics in the form of frequency distributions or sample means and standard deviations as well as Spearman correlations for year/gender, year/stage and year/age were found. We used a T-test to compare subjects between Zambia and USA. A p-value < 0.05 was considered significant. Results: 377 charts were identified in the CDH database between 2007 and 2015 with 234 meeting inclusion criteria for the final analysis. The mean ages were 48.6 years for the Zambian group, 69.4 years for SEER group, and 65.6 years for only AA SEER group. The difference is highly significant in both cases (p < 0.0001). In the Zambia sample, 62% are males, which is significantly higher than all SEER (51%, p=0.0008) and higher than only AA SEER black (48%, p < 0.0001). Using descriptive analysis for patterns in the Zambian group: mode of diagnosis was surgical in 195 subjects (84%), histology adenocarcinoma in 225 (96.5%), most common location is rectum 124 (53%) followed by sigmoid 31 (13.4), and cecum 26 (26%). 122 subjects (54%) were Stage 4 at diagnosis. A trend test shows no difference across years relative to the proportions of male/female (p=0.56). Using the Spearman Rank correlation, we see no association between Year and Stage (p=0.30) or Year and Age (p=0.92). Conclusion: Colorectal cancer occurs at a significantly younger age in the native African population when compared to an African-American population. Further studies are necessary to elucidate risk factors which could help develop screening protocols and understand the pathway of cancer development.

Mutations in the tyrosine kinase domain of the EGFR gene are rare in the Korean Oral Squamous Cell Carcinoma

The epidermal growth factor receptor(EGFR) protein kinase signaling is an important pathway in cancer development and recently reported that EGFR and its kinase domain molecules are mutated in various of cancers including head and neck cancer. Functional deregulation of EGFR due to mutations in coding exons and copy number amplification is the most common event in cancers, especially among receptor tyrosine kinases(TK). We have analyzed Korean oral squamous cell carcinomas (OSCC) cell lines for mutations in EGFRTK. Exons encoding the hot-spot regions in the TK domain of EGFR (exons 17 to 23) were amplified by using polymerase chain reaction(PCR) and sequenced directly. EGFR expression was also analyzed in 8 OSCC cell lines using western blotting. Data analysis of the EGFR exons 17 to 23 coding sequences did not show any mutations in the 8 OSCC cell lines that were analyzed. The absence of mutations indicate that protein overexpression might be responsible for activation rather than mutation.

β-caryophyllene and β-caryophyllene oxide-natural compounds of anticancer and analgesic properties.

Natural bicyclic sesquiterpenes, β‐caryophyllene (BCP) and β‐caryophyllene oxide (BCPO), are present in a large number of plants worldwide. Both BCP and BCPO (BCP(O)) possess significant anticancer activities, affecting growth and proliferation of numerous cancer cells. Nevertheless, their antineoplastic effects have hardly been investigated in vivo. In addition, both compounds potentiate the classical drug efficacy by augmenting their concentrations inside the cells. The mechanisms underlying the anticancer activities of these sesquiterpenes are poorly described. BCP is a phytocannabinoid with strong affinity to cannabinoid receptor type 2 (CB 2), but not cannabinoid receptor type 1 (CB 1). In opposite, BCP oxidation derivative, BCPO, does not exhibit CB 1/2 binding, thus the mechanism of its action is not related to endocannabinoid system (ECS) machinery. It is known that BCPO alters several key pathways for cancer development, such as mitogen‐activated protein kinase (MAPK), PI3K/AKT/mTOR/S6K1 and STAT3 pathways. In addition, treatment with this compound reduces the expression of procancer genes/proteins, while increases the levels of those with proapoptotic properties. The selective activation of CB 2 may be considered a novel strategy in pain treatment, devoid of psychoactive side effects associated with CB 1 stimulation. Thus, BCP as selective CB 2 activator may be taken into account as potential natural analgesic drug. Moreover, due to the fact that chronic pain is often an element of cancer disease, the double activity of BCP, anticancer and analgesic, as well as its beneficial influence on the efficacy of classical chemotherapeutics, is particularly valuable in oncology. This review is focused on anticancer and analgesic activities of BCP and BCPO, the mechanisms of their actions, and potential therapeutic utility.

The Role of Cholesterol in Cancer.

The roles played by cholesterol in cancer development and the potential of therapeutically targeting cholesterol homeostasis is a controversial area in the cancer community. Several epidemiologic studies report an association between cancer and serum cholesterol levels or statin use, while others suggest that there is not one. Furthermore, the Cancer Genome Atlas (TCGA) project using next-generation sequencing has profiled the mutational status and expression levels of all the genes in diverse cancers, including those involved in cholesterol metabolism, providing correlative support for a role of the cholesterol pathway in cancer development. Finally, preclinical studies tend to more consistently support the role of cholesterol in cancer, with several demonstrating that cholesterol homeostasis genes can modulate development. Because of space limitations, this review provides selected examples of the epidemiologic, TCGA, and preclinical data, focusing on alterations in cholesterol homeostasis and its consequent effect on patient survival. In melanoma, this focused analysis demonstrated that enhanced expression of cholesterol synthesis genes was associated with decreased patient survival. Collectively, the studies in melanoma and other cancer types suggested a potential role of disrupted cholesterol homeostasis in cancer development but additional studies are needed to link population-based epidemiological data, the TCGA database results, and preclinical mechanistic evidence to concretely resolve this controversy. Cancer Res; 76(8); 2063-70. ©2016 AACR.

CTNNB1-mutant colorectal carcinomas with immediate invasive growth: a model of interval cancers in Lynch syndrome.

The implementation of regular colonoscopy programs has significantly decreased the mortality associated with colorectal cancer (CRC) in Lynch syndrome patients. However, interval CRCs in Lynch syndrome that remain undetected by colonoscopy still represent a substantial problem in the management of the syndrome. One possible reason of interval cancers could be a non-polypous pathway of cancer development. To examine the possibility of a non-polypous pathway of CRC development in Lynch syndrome, we analyzed the histological appearance of 46 Lynch syndrome-associated CRCs and compared them to 34 sporadic microsatellite unstable cancers. We observed that 25 (62.5%) out of 40 assessable Lynch syndrome-associated carcinomas lacked evidence of polypous growth, compared to 17 (50%) out of 34 sporadic MSI-H cancers. We detected CTNNB1 mutations in 8 (17.4%) out of 46 Lynch syndrome-associated cancers compared to 0 out of 34 sporadic MSI-H cancers (p=0.01). The majority of CTNNB1-mutant cancers presented with a histological appearance suggesting immediate invasive growth. Our results suggest that a distinct subgroup of CRCs in Lynch syndrome may in fact emerge from a non-polypous precursor, thus potentially explaining the phenomenon of interval cancers. Such a non-polypous precursor may be the recently described mismatch repair-deficient crypt focus, which remains invisible for the examiner during colonoscopy. This calls for considering the implementation of active, primary preventive measures in the management of Lynch syndrome. Future studies on pathogenic pathways and precursor lesions in Lynch syndrome are strongly encouraged, and the clinical efficacy of new prevention approaches should be evaluated in prospective clinical trials.

Targeting Insulin Receptor with a Novel Internalizing Aptamer

Nucleic acid-based aptamers are emerging as therapeutic antagonists of disease-associated proteins such as receptor tyrosine kinases. They are selected by an in vitro combinatorial chemistry approach, named Systematic Evolution of Ligands by Exponential enrichment (SELEX), and thanks to their small size and unique chemical characteristics, they possess several advantages over antibodies as diagnostics and therapeutics. In addition, aptamers that rapidly internalize into target cells hold as well great potential for their in vivo use as delivery tools of secondary therapeutic agents. Here, we describe a nuclease resistant RNA aptamer, named GL56, which specifically recognizes the insulin receptor (IR). Isolated by a cell-based SELEX method that allows enrichment for internalizing aptamers, GL56 rapidly internalizes into target cells and is able to discriminate IR from the highly homologous insulin-like growth factor receptor 1. Notably, when applied to IR expressing cancer cells, the aptamer inhibits IR dependent signaling. Given the growing interest in the insulin receptor as target for cancer treatment, GL56 reveals a novel molecule with great translational potential as inhibitor and delivery tool for IR-dependent cancers.