GNPX 2017 Annual Report

25 Preclinical Studies of Additional 3p21.3 Genes with Cancer-Fighting Properties We have licensed rights to a group of candidate tumor suppressor genes, including 101F6, NPRL2, CACNA2D2, PL6, BLU, RASSF1, HYAL 1 and HYAL2, in addition to TUSC2 (which is also referred to as FUS1), all of which are located in a sub-region of human chromosome 3 known as 3p21.3. Using a number of techniques, MD Anderson researchers and their collaborators have identified these genes as potentially having cancer-fighting characteristics. MD Anderson researchers have subsequently conducted a number of preclinical studies on certain of these genes, particularly 101F6 and NPRL2, as well as TUSC2, both alone and in combination with other compounds, in order to assess their actual effects on NSCLC. Three of these preclinical studies are described below. We plan to support continuing research into the cancer-fighting properties of these and other genes in the 3p21.3 sub-region as an important part of our strategy. Preclinical Study Showing Expression of Several Genes in the Human Chromosome 3p21.3 Sub-region by an Adenovirus Vector Results in Tumor Suppressor Activities in Vitro and in Vivo MD Anderson researchers conducted preclinical studies, both in vitro and in vivo, of several of the licensed genes located in the 3p21.3 sub-region, in order to assess their effects on tumor cell proliferation and apoptosis in human lung cancer cells. The researchers used adenoviral vectors to introduce individual wild-type genes into 3p-deficient tumor xenografts and tumor cell lines. This “forced expression” of the wild-type forms of TUSC2, 101F6, and NPRL2 resulted in inhibition of tumor cell growth by induction of apoptosis and/or alteration of cell cycle pathways in vitro, compared to control. Intratumoral injection of 101F6, TUSC2 and NPRL2 with adenoviral vectors, as well as systemic administration of these genes in an experimental mouse model, suppressed the growth of tumor xenografts (in this case, human tissue grafted onto the mouse model) and inhibited lung metastases. The results of these studies showed that the genes 101F6, NPRL2 and TUSC2 had the most significant anti-cancer effects of the tested genes and were therefore the most promising genes for further study. Preclinical Study Showing that Tumor Suppressor 101F6 and Ascorbate Inhibit Non–Small Cell Lung Cancer Growth One of the promising tumor suppressor gene candidates, 101F6, expresses a protein found in normal lung bronchial epithelial cells and fibroblasts but whose function is impaired in most lung cancers. This protein is involved in the regeneration of ascorbate, a well-known antioxidant that has been tested as a supplemental therapeutic agent for human cancer prevention and therapy. MD Anderson researchers studied the effect of 101F6 in combination with ascorbate on human lung cancer tissue, both in vitro and in vivo. In the in vitro portion of the study, 101F6 was transferred via nanoparticles similar to our Oncoprex nanovesicles, and in combination with ascorbate, selectively targeted cancer cells and inhibited lung cancer cell growth to a greater extent than either 101F6 or ascorbate alone. In vivo, the systemic injection of 101F6 nanoparticles in mouse tail veins, together with the intra-abdominal injection of ascorbate, inhibited both tumor formation and growth in human NSCLC H322 lung cancer xenograft mouse models (P < 0.001) with greater effect than either 101F6 or ascorbate administered alone. Preclinical Study Showing NPRL2 Sensitizes Human Non-Small Cell Lung Cancer (NSCLC) Cells to Cisplatin Treatment by Regulating Key Components in the DNA Repair Pathway Another of the promising tumor suppressor gene candidates, NPRL2, interacts with a kinase that is activated by cisplatin, an anti-cancer drug, leading to downstream activation of apoptosis in response to the presence of intracellular high-molecular weight DNA fragments, which themselves result from the breakup of DNA molecules induced by exposure to cisplatin. Mutations in the NPRL2 gene are associated with resistance to this cisplatin-mediated apoptosis. MD Anderson researchers have conducted preclinical studies of NPRL2 with cisplatin in vitro in lung cancer cell cultures and in vivo in an experimental mouse model of chest cavity cancer dissemination. Data from these studies suggest that the systemic introduction of the NPRL2 gene and the resulting expression of the NPRL2 protein in cancer cells activates the DNA damage checkpoint pathway in cisplatin-resistant and NPRL2-negative cells. These studies suggest that the combination of NPRL2 and cisplatin could resensitize cisplatin nonresponders to cisplatin treatment, helping to overcome resistance to cisplatin.