Hsa-miR-205 is a highly accurate marker for lung cancer of squamous histology. The standardized diagnostic assay presented here can provide highly accurate subclassification of NSCLC patients.

MiR-125 is a highly conserved microRNA throughout many different species from nematode to humans. In humans, there are three homologs (hsa-miR-125b-1, hsa-miR-125b-2 and hsa-miR-125a). Here we review a recent research on the role of miR-125 in normal and malignant hematopoietic cells. Its high expression in hematopoietic stem cells (HSCs) enhances self-renewal and survival. Its expression in specific subtypes of myeloid and lymphoid leukemias provides resistance to apoptosis and blocks further differentiation. A direct oncogenic role in the hematopoietic system has recently been demonstrated by several mouse models. Targets of miR-125b include key proteins regulating apoptosis, innate immunity, inflammation and hematopoietic differentiation.

MicroRNAs (miRNAs) regulate the expression of multiple proteins in a dose dependent manner. We hypothesized that increased expression of miRNAs encoded on chromosome 21 (chr 21) contribute to the leukemogenic role of trisomy 21. The levels of chr 21 miRNAs were quantified by qRT-PCR in four types of childhood ALL characterized by either numerical (trisomy or tetrasomy) or structural abnormalities of chr 21. Suprisingly high expression of the hsa-mir-125b-2 cluster, consisting of three miRNAs, was identified in leukemias with the structural ETV6/RUNX1 abnormality and not in ALLs with trisomy 21. Manipulation of ETV6/RUNX1 expression and chromatin immunoprecipitation studies demonstrated that the high expression of the miRNA cluster is an event independent of the ETV6/RUNX1 fusion protein. Overexpression of hsa-mir-125b-2 conferred a survival advantage to Ba/F3 cells following IL-3 withdrawal or a broad spectrum of apoptotic stimuli through inhibition of caspase 3 activation. Conversely, knockdown of the endogenous miR-125b in the ETV6/RUNX1 leukemia cell line REH increased apoptosis after Doxorubicin and Staurosporine treatments. P53 protein levels were not altered by miR-125b. Together these results suggest that the expression of hsa-mir-125b-2 in ETV6/RUNX1 ALL provides survival advantage to growth inhibitory signals in a p53 independent manner.

MicroRNAs (miRNAs) are small non-coding RNAs with regulatory roles, which are involved in a broad spectrum of physiological and pathological processes, including cancer. A common strategy for identification of miRNAs involved in cell transformation is to compare malignant cells to normal cells. Here we focus on identification of miRNAs that regulate the aggressive phenotype of melanoma cells. To avoid differences due to genetic background, a comparative high-throughput miRNA profiling was performed on two isogenic human melanoma cell lines that display major differences in their net proliferation, invasion and tube formation activities. This screening revealed two major cohorts of differentially expressed miRNAs. We speculated that miRNAs up-regulated in the more-aggressive cell line contribute oncogenic features, while the down-regulated miRNAs are tumor suppressive. This assumption was further tested experimentally on five candidate tumor suppressive miRNAs (miR-31, -34a, -184, -185 and -204) and on one candidate oncogenic miRNA (miR-17-5p), all of which have never been reported before in cutaneous melanoma. Remarkably, all candidate Suppressive-miRNAs inhibited net proliferation, invasion or tube formation, while miR-17-5p enhanced cell proliferation. miR-34a and miR-185 were further shown to inhibit the growth of melanoma xenografts when implanted in SCID-NOD mice. Finally, all six candidate miRNAs were detected in 15 different metastatic melanoma specimens, attesting for the physiological relevance of our findings. Collectively, these findings may prove instrumental for understanding mechanisms of disease and for development of novel therapeutic and staging technologies for melanoma.

No abstract

Cancer immunotherapies are revolutionizing cancer treatment. Unfortunately, a large proportion of patients with solid tumors do not respond to currently available immune-therapeutics. The lack of response is due to a variety of mechanisms tumors adopt to avoid immune mediated clearance. The multiplicity of immunosuppressive mechanisms operational in the tumor microenvironment may not be overcome by single agents and require interventions at multiple control points. However, systemic exposure to combinations of immunoregulators may result in severe, dose limiting, acute and chronic toxicities that might be prevented if the effect of these agents is focused to the tumor microenvironment. We are engaged in the discovery of a novel class of immuno-oncology drugs aimed at maximizing the effect of immunoregulatory molecules in the tumor microenvironment and minimizing systemic adverse effects. These drugs incorporate plasmids, engineered to program tumor cells to produce and secrete immune-regulatory proteins, within hyaluronic acid (HA) coated lipid nanoparticles, called GAGomers, which specifically target tumor cells that overexpress activated HA receptors (GAG-pDNA). GAG-pDNA based therapeutics promise highly potent but localized activation of the immune system exclusively in the tumor microenvironment following systemic administration, leading to the destruction of tumor cells by activated immune cells without debilitating toxic side effects. To demonstrate the feasibility of the GAG-pDNA approach we have incorporated a plasmid directing the expression of murine IL-2 into GAGomers (GAG-pIL2) and assessed the anti-tumor activity of the construct after systemic delivery into tumor bearing mice. GAG-pIL2 administration resulted in statistically significant inhibition of tumor growth, which correlated with elevated IL-2 levels in the tumor and increased infiltration of T-cells into the tumor microenvironment. These experiments demonstrate the feasibility of programming tumor cells using GAG-pDNA to produce and secrete immunoregulatory molecules into the tumor microenvironment and trigger robust anti-tumor immune responses. Citation Format: Genia Alpert, David Altreuter, Sunil Anamandla, Arlyssa Birt, Guy Cinamon, Keren Cohen Merimi, Orli Even Or, Nir Gefen, Nadia Gurvich, Jeno Gyuris, Lorena Lerner, Adi Mondshine, Hong Wang. Anti-tumor effect of GAGomer-mediated intra-tumoral IL-2 expression following systemic administration [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 1601. doi:10.1158/1538-7445.AM2017-1601

Small-interfering RNAs and microRNAs are small ∼21–22 nucleotide long RNAs capable of posttranscriptional suppression of gene expression. The synthetic siRNAs are especially designed to target pre-specified genes and are common molecular biology tools. The miRNAs are endogenous regulators of gene expression found in a wide variety of eukaryotes. miRNAs are currently utilized for diagnostics applications. Therapeutically, various miRNA-antagonizing tools are being explored and miRNAs are also utilized for cell-specific inhibition of the expression of gene therapy vectors harboring target sites for specific miRNAs. Here we show, for the first time, that siRNAs and miRNAs can be harnessed to induce gene expression. We designed special expression vectors in which target sites for artificial siRNAs or endogenous miRNAs are located between the transgene and an Upstream Inhibitory Region (UIR). We hypothesized that cleavage of the mRNA by siRNAs or miRNAs will separate the transgene from the UIR and the resulting uncapped mRNA will be capable of being translated. A UIR composed of seven open reading frames was found to be the most efficient inhibitor of the translation of the downstream transgene. We show that under such a configuration both artificial siRNAs and endogenous miRNAs were capable of inducing transgene expression. We show that using the diphtheria toxin A-chain gene, in combination with target sites for highly expressed miRNAs, specific induction of cell-death can be achieved, setting the stage for application to cancer therapy.