Canine glioblastoma-derived extracellular vesicles as precise carriers for glioblastoma imaging: Targeting across the blood-brain barrier

The treatment of glioblastoma (GBM) faces significant challenges due to the difficulty of delivering drugs through the blood-brain barrier (BBB). Extracellular vesicles (EVs) have emerged as potential carriers for targeted drug delivery to brain tumors. However, their use and distribution in the presence of an intact BBB and their ability to target GBM tissue are still under investigation. This study explored the use of EVs for GBM targeting across the BBB. Canine plasma EVs from healthy dogs and dogs with glioma were isolated, characterized, and loaded with diagnostic agents. Biodistribution studies were conducted in healthy murine models and a novel intranasal model that preserved BBB integrity while initiating early-stage GBM growth. This model assessed EVs' potential for delivering the contrast agent gadoteric acid to intracranial tumors. Imaging techniques, such as bioluminescence and MRI, confirmed EVs' targeting and delivery capabilities thus revealing a selective accumulation of canine glioma-derived EVs in brain tissue under physiological conditions. In the model of brain tumor, MRI experiments demonstrated the ability of EVs to accumulate gadoteric acid within GBM to enhance contrast of the tumoral mass, even when BBB integrity is maintained. This study underscores the potential of EVs derived from glioma for the targeted delivery of drugs to glioblastoma. EVs from dogs with glioma showed capacity to traverse the BBB and selectively accumulate within the brain tumor. Overall, this research represents a foundation for the application of autologous EVs to precision glioblastoma treatment, addressing the challenge of BBB penetration and targeting specificity in brain cancer therapy.

Increased Sensitivity of Computed Tomography Scan for Neoplastic Tissues Using the Extracellular Vesicle Formulation of the Contrast Agent Iohexol

Computed tomography (CT) is a diagnostic medical imaging modality commonly used to detect disease and injury. Contrast agents containing iodine, such as iohexol, are frequently used in CT examinations to more clearly differentiate anatomic structures and to detect and characterize abnormalities, including tumors. However, these contrast agents do not have a specific tropism for cancer cells, so the ability to detect tumors is severely limited by the degree of vascularization of the tumor itself. Identifying delivery systems allowing enrichment of contrast agents at the tumor site would increase the sensitivity of detection of tumors and metastases, potentially in organs that are normally inaccessible to contrast agents, such as the CNS. Recent work from our laboratory has identified cancer patient-derived extracellular vesicles (PDEVs) as effective delivery vehicles for targeting diagnostic drugs to patients' tumors. Based on this premise, we explored the possibility of introducing iohexol into PDEVs for targeted delivery to neoplastic tissue. Here, we provide preclinical proof-of-principle for the tumor-targeting ability of iohexol-loaded PDEVs, which resulted in an impressive accumulation of the contrast agent selectively into the neoplastic tissue, significantly improving the ability of the contrast agent to delineate tumor boundaries.

miR-342 overexpression results in a synthetic lethal phenotype in BRCA1-mutant HCC1937 breast cancer cells

Expression of miR-342 has been strongly correlated with estrogen receptor (ER) status in breast cancer, where it is highest in ER-positive and lowest in triple-negative tumors. We investigated the effects of miR-342 transfection in the triple-negative breast cancer cell lines MDA-MB-231 and HCC1937, the latter carrying a germ-line BRCA1 mutation. Reconstitution of miR-342 led to caspase-dependent induction of apoptosis only in HCC1937 cells, while overexpression of wild-type BRCA1 in HCC1937 cells counteracted miR-342-mediated induction of apoptosis, suggesting that miR-342 overexpression and the lack of functional BRCA1 result in a synthetic lethal phenotype. Moreover, siRNA-mediated depletion of BRCA1 in MDA-MB-231 cells expressing the wild-type protein led to apoptosis upon transfection with miR-342. Using an in silico approach and a luciferase reporter system, we identified and functionally validated the Baculoviral IAP repeat-containing 6 gene (BIRC6), which encodes the anti-apoptotic factor Apollon/BRUCE, as a target of miR-342. In our model, BIRC6 likely acts as a determinant of the miRNA-dependent induction of apoptosis in BRCA1-mutant HCC1937 cells. Together, our findings suggest a tumor-suppressive function of miR-342 that could be exploited in the treatment of a subset of BRCA1-mutant hereditary breast cancers.

Integration of genome scale data for identifying new players in colorectal cancer

Colorectal cancers (CRCs) display a wide variety of genomic aberrations that may be either causally linked to their development and progression, or might serve as biomarkers for their presence. Recent advances in rapid high-throughput genetic and genomic analysis have helped to identify a plethora of alterations that can potentially serve as new cancer biomarkers, and thus help to improve CRC diagnosis, prognosis, and treatment. Each distinct data type (copy number variations, gene and microRNAs expression, CpG island methylation) provides an investigator with a different, partially independent, and complementary view of the entire genome. However, elucidation of gene function will require more information than can be provided by analyzing a single type of data. The integration of knowledge obtained from different sources is becoming increasingly essential for obtaining an interdisciplinary view of large amounts of information, and also for cross-validating experimental results. The integration of numerous types of genetic and genomic data derived from public sources, and via the use of ad-hoc bioinformatics tools and statistical methods facilitates the discovery and validation of novel, informative biomarkers. This combinatory approach will also enable researchers to more accurately and comprehensively understand the associations between different biologic pathways, mechanisms, and phenomena, and gain new insights into the etiology of CRC.

The Effects of miR-20a on p21: Two Mechanisms Blocking Growth Arrest in TGF-β-Responsive Colon Carcinoma

Loss of response to TGF-β is a central event in the genesis of colorectal cancer (CRC), a disease that, in the majority cases, is refractory to growth inhibition induced by this cytokine. However, inactivating mutations at receptors and transducers from the TGF-β cascade occur only in approximately half of CRCs, suggesting the involvement of additional mechanisms altering the response to the cytokine. We have recently described the amplification of the 13q31 locus, where the miR-17-92 cluster maps, associated with overexpression of its members. In this study, we address the potential role of miR-20a, from the miR-17-92 cluster, in the suppression of TGF-β cytostatic response in CRC. Using the poorly tumorigenic and TGF-β-sensitive FET cell line that expresses low miR-20a levels, we first confirmed that miR-20a downmodulated CDKN1A expression, both at mRNA and protein level, through direct binding to its 3'-UTR. We demonstrated that miR-20a significantly diminished cell response to TGF-β by preventing its delay of G1/S transition and promoting progression into cell cycle. Moreover, besides modulating CDKN1A, miR-20a blocked TGF-β-induced transactivation of its promoter without affecting the post-receptor activation of Smad3/4 effectors directly. Finally, miR-20a abrogated the TGF-β-mediated c-Myc repression, a direct inhibitor of the CDKN1A promoter activation, most likely by reducing the expression of specific MYC-regulating genes from the Smad/E2F-based core repressor complex. Our experiments indicate that miR-20a interferes with the colonic epithelium homeostasis by disrupting the regulation of Myc/p21 by TGF-β, which is essential for its malignant transformation.

miR-342 regulates BRCA1 expression through modulation of ID4 in breast cancer

A miRNAs profiling on a group of familial and sporadic breast cancers showed that miRNA-342 was significantly associated with estrogen receptor (ER) levels. To investigate at functional level the role of miR-342 in the pathogenesis of breast cancer, we focused our attention on its "in silico" predicted putative target gene ID4, a transcription factor of the helix-loop-helix protein family whose expression is inversely correlated with that of ER. ID4 is expressed in breast cancer and can negatively regulate BRCA1 expression. Our results showed an inverse correlation between ID4 and miR-342 as well as between ID4 and BRCA1 expression. We functionally validated the interaction between ID4 and miR-342 in a reporter Luciferase system. Based on these findings, we hypothesized that regulation of ID4 mediated by miR-342 could be involved in the pathogenesis of breast cancer by downregulating BRCA1 expression. We functionally demonstrated the interactions between miR-342, ID4 and BRCA1 in a model provided by ER-negative MDA-MB-231 breast cancer cell line that presented high levels of ID4. Overexpression of miR-342 in these cells reduced ID4 and increased BRCA1 expression, supporting a possible role of this mechanism in breast cancer. In the ER-positive MCF7 and in the BRCA1-mutant HCC1937 cell lines miR-342 over-expression only reduced ID4. In the cohort of patients we studied, a correlation between miR-342 and BRCA1 expression was found in the ER-negative cases. As ER-negative cases were mainly BRCA1-mutant, we speculate that the mechanism we demonstrated could be involved in the decreased expression of BRCA1 frequently observed in non BRCA1-mutant breast cancers and could be implicated as a causal factor in part of the familial cases grouped in the heterogeneous class of non BRCA1 or BRCA2-mutant cases (BRCAx). To validate this hypothesis, the study should be extended to a larger cohort of ER-negative cases, including those belonging to the BRCAx class.

Abstract 2295: miR-342 modulates ID4 expression in breast cancer

Integration of the results from a transcriptome profiling of coding and non coding RNAs (miRNA) on familial (BRCA1- or BRCA2-mutated, or BRCAX) and sporadic breast cancers identified possible miRNA-dependent mechanisms associated with the different BRCA groups analyzed. Among the miRNA/target gene pairs found, we focused on that composed by miR-342 and ID4 gene. ID4 is a negative regulator of B-HLH transcription factors frequently expressed in cancer and miR-342 is deregulated in many cancers, including breast. All of our groups had relatively high expression of miR-342 and low expression of ID4, except for one subgroup of BRCAX cases (named BRCAXa, comprising cases with clinical characteristics similar to BRCA1) that had reciprocal expression patterns of this pair. We evaluated the expression levels of the putative pair in different breast cancer cell lines and found that ID4 gene expression was on average higher in estrogen receptor negative (ER-) cells; on the contrary, miR-342 had higher expression in estrogen receptor positive (ER+) cells. The direct binding of miR-342 to the 3′ UTR of ID4 and its potential inhibitory effect was functionally validated using a reporter luciferase system. Reciprocal expression of miR-342 and ID4 was then confirmed in vitro in the triple negative MDA-MB-231 cell line, that, similarly to the BRCAXa subgroup, had low expression of miR-342 and where miR-342 introduction reduced ID4 protein levels. ID4 is a negative regulator of BRCA1 and modulation of its expression in breast cancer is inversely related with that of BRCA1. Being ID4 a target of miR-342, we hypothesized a relationship between these two genes and the miRNA and that low levels of miR-342 could provide a mechanism for increasing ID4 that negatively regulates BRCA1 expression. Analysis of their levels in our cases supported this thesis. In the BRCAXa class lower levels of miR-342 were associated with reduced expression of BRCA1. We hypothesized that down-regulation of ID4 through miR-342 could provide a mechanism for increasing BRCA1 expression. We tested this hypothesis in the MDA-MB-231 cells, where we found miR-342 mediated downregulation of ID4, but no increase in the expression of BRCA1 at either gene or protein levels. These results showed that ID4 is a validated target of miR342 and propose a role of miR-342 in familial breast cancer where it could impair expression of ID4. Targets of ID4 different than BRCA1 can be altered in the BRCAXa subgroup.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2295. doi:1538-7445.AM2012-2295

Abstract 3959: Growth suppression by TGF-β in responsive colon carcinoma is opposed by miR-20a through mechanisms altering p21WAF1 up-regulation

Loss of response to TGF-β occurs in many cancers and disruption of its regulatory circuitry appears as a central event in the genesis of colorectal cancer (CRC) malignancy. Lack of inhibitory response to TGF-β is common to most colon cancer cell lines. However, inactivating mutations at receptors and transducers occur in less than a half of neoplastic colon tissues, which underscore the significance of additional mechanisms diverting TGF-β growth suppression. In this context, abrogation of TGF-β response by some miRNAs has been recently reported.

By searching for miRNAs in regions showing copy number changes and concordant gene expression in 36 sporadic CRCs compared to their normal counterpart, we identified the miR-17-92 cluster on the 13q31 locus, which is gained and highly expressed at early stages of CRC. MiR-20a from miR-17-92 cluster is a paralog of the miR-106b, which affects TGF-β sensitivity in gastric carcinoma. We hypothesized an involvement of miR-20a in the suppression of TGF-β response in CRCs and selected the TGF-β sensitive FET colon carcinoma, expressing low miR-20a levels, to investigate the relationship between enhanced expression of miR-20a and TGF-β sensitivity and address growth inhibition.

We report that miR-20a affects regulation of p21WAF1 expression, has a negative and significant effect on the cytostatic response mediated by TGF-β – evaluated by BrdU incorporation, MTT assay, and cell-cycle analysis – but shows little effect on TGF-β untreated cells. Although p21WAF1 transcript and protein are significantly decreased in cells treated or not with the cytokine, we could observe that the p21 up-regulation driven by TGF-β is strongly subverted by miR-20a. One potential mechanism of p21 down-modulation by miR-20a can be the targeting of its 3’UTR, as occurring for miR-106a. Moreover, we could observe that miR-20a is also able to block the transactivation of the 2.3-kb p21 promoter upon TGF-β stimulation, as assessed by luciferase-based assay, but not the activation of the Smad3/4-reponsive reporter. Down-modulation of c-Myc by TGF-β, crucial to regulation of p21 transcription, is also subverted by miR-20a delivery into cells.

Our experiments suggest for miR-20a an interference with the TGF-β homeostasis in colon addressing the up-regulation of p21 expression, through mechanisms involving more effectors of the TGF-β cascade. Overall, miR-20a seems to participate in the abrogation of this key regulatory response in colonic epithelium.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3959. doi:10.1158/1538-7445.AM2011-3959

Chronic productive cough in young adults is very often due to chronic rhino-sinusitis

BACKGROUND

Chronic productive cough is a common clinical problem; often potential causes outside the lower respiratory tract are forgotten or ignored. The aim of this study was to make a precise etiopathogenetic diagnosis of chronic productive cough in young adults.

METHODS

In a clinical setting, 212 subjects (mean age 41+/-5 years) who had reported chronic productive cough in a previous postal survey of a young adult population underwent within two years clinical and functional investigations following a rational diagnostic approach. Two pulmonologists independently established the diagnosis using a clinically structured interview on nasal and respiratory symptoms, spirometry and other tests when appropriate (bronchodilator test or methacholine bronchial challenge, chest radiography); if rhino-sinusitis was suspected, subjects underwent an ENT examination with nasal endoscopy and/or sinus computed tomography.

RESULTS

At the end of the diagnostic procedure, 87 subjects (41%) no longer had chronic productive cough and had normal function. Fifty-eight subjects (27%) had chronic rhino-sinusitis; seventeen subjects (8%) had asthma, and of these fourteen also had chronic rhino-sinusitis; 50 subjects (24%) had COPD stage 0+, of these seven also had chronic rhino-sinusitis. Chronic rhino-sinusitis was more frequent in females than in males (p<0.05).

CONCLUSIONS

Both in clinical practice and in epidemiological studies, it is important to consider that the origin of chronic productive cough could be frequently outside the lower respiratory tract; a consistent percentage of young adults with persistent productive cough has indeed chronic rhino-sinusitis.