IMP3 Immunohistochemical Expression Is Related with Progression and Metastases in Xenografted and Cutaneous Melanomas

INTRODUCTION

Insulin-like growth factor-II messenger RNA-binding protein-3 (IMP3) over-expression is a predictor of tumor recurrence and metastases in some types of human melanoma. Our objective was to evaluate the immunohistochemical expression of IMP3 and other molecules related to tumor prognosis in melanoma-xeno-tumors undergoing treatment. We test the effect of radiotherapy (RT) and mesenchymal stromal cells (MSCs) treatment, analyzing the tumorigenic and metastatsizing capacity in a mice melanoma xenograft model.

MATERIALS AND METHODS

We inoculated A375 and G361 human melanoma cell lines into NOD/SCID gamma mice (n = 64). We established a control group, a group treated with MSCs, a group treated with MSCs plus RT, and a group treated with RT. We assessed the immunohistochemical expression of IMP3, E-cadherin, N-cadherin, PARP1, HIF-1α, and the proliferation marker Ki-67. Additionally, we performed a retrospective study including 114 histological samples of patients diagnosed with malignant cutaneous superficial spreading melanoma (n = 104) and nodular melanoma (n = 10) with at least 5 years of follow-up.

RESULTS

Most morphological and immunohistochemical features show statistically significant differences between the 2 cell lines. The A375 cell line induced the formation of metastases, while the G361 cell line provoked tumor formation but not metastases. All three treatments reduced the cell proliferation evaluated by the Ki-67 nuclear antigen (p = 0.000, one-way ANOVA test) and reduced the number of metastases (p = 0.004, one-way ANOVA test). In addition, the tumor volumes reduced in comparison with the control groups, 31.74% for RT + MSCs in the A357 tumor cell line, and 89.84% RT + MSCs in the G361 tumor cell line. We also found that IMP3 expression is associated with greater tumor aggressiveness and was significantly correlated with cell proliferation (measured by the expression of Ki-67), the number of metastases, and reduced expression of adhesion molecules.

CONCLUSIONS

The combined treatment of RT and MSCs on xenografted melanomas reduces tumor size, metastases frequency, and the epithelial to mesenchymal transition/PARP1 metastatic phenotype. This treatment also reduces the expression of molecules related to cellular proliferation (Ki-67), molecules that facilitate the metastatic process (E-cadherin), and molecules related with prognosis (IMP3).

Epigenetic modifiers either individually or in specific combinations impair viability of patient-derived glioblastoma cell line while exhibiting moderate effect on normal stem cells growth

Glioblastomas (GBM), also known as glioblastoma multiforme, are the most aggressive type of brain cancers. Currently, there is no real treatment for GBM and thus there is a compelling need for new therapeutic strategies for such type of cancers. Recently, we demonstrated that specific combinations of epigenetic modifiers significantly affect the metabolism and proliferation rate of two most aggressive GBM cell lines D54 and U-87. Importantly, these combinations exhibited minimal effect on normal stem cells growth. In this study we demonstrated that the combinations of modulators of histone and DNA covalent modifying enzymes that synergistically suppress D54 and U87 cell lines growth, also impair the viability of a patient freshly-derived GBM stem cell line. These data suggest that epigenetic modifiers alone or in specific combinations exhibit cytotoxic effect on established and low passage patient derived GB cell lines and thus could be a promising therapeutic approach for such type of brain cancers.

Development of Experimental Three-Dimensional Tumor Models to Study Glioblastoma Cancer Stem Cells and Tumor Microenvironment

Glioblastoma (GBM) is the most common and dismal primary brain tumor. Unfortunately, despite multidisciplinary treatment, most patients will perish approximately 15 months after diagnosis. For this reason, there is an urgent need to improve our understanding of GBM tumor biology and develop novel therapies that can achieve better clinical outcomes. In this setting, three-dimensional tumor models have risen as more appropriate preclinical tools when compared to traditional cell cultures, given that two-dimensional (2D) cultures have failed to accurately recapitulate tumor biology and translate preclinical findings into patient benefits. Three-dimensional cultures using neurospheres, organoids, and organotypic better resemble original tumor genetic and epigenetic profiles, maintaining tumor microenvironment characteristics and mimicking cell-cell and cell-matrix interactions. This chapter summarizes our methods to generate well-characterized glioblastoma neurospheres, organoids, and organotypics.

Identification of Synergistic Drug Combinations to Target KRAS-Driven Chemoradioresistant Cancers Utilizing Tumoroid Models of Colorectal Adenocarcinoma and Recurrent Glioblastoma

Treatment resistance is observed in all advanced cancers. Colorectal cancer (CRC) presenting as colorectal adenocarcinoma (COAD) is the second leading cause of cancer deaths worldwide. Multimodality treatment includes surgery, chemotherapy, and targeted therapies with selective utilization of immunotherapy and radiation therapy. Despite the early success of anti-epidermal growth factor receptor (anti-EGFR) therapy, treatment resistance is common and often driven by mutations in APC, KRAS, RAF, and PI3K/mTOR and positive feedback between activated KRAS and WNT effectors. Challenges in the direct targeting of WNT regulators and KRAS have caused alternative actionable targets to gain recent attention. Utilizing an unbiased drug screen, we identified combinatorial targeting of DDR1/BCR-ABL signaling axis with small-molecule inhibitors of EGFR-ERBB2 to be potentially cytotoxic against multicellular spheroids obtained from WNT-activated and KRAS-mutant COAD lines (HCT116, DLD1, and SW480) independent of their KRAS mutation type. Based on the data-driven approach using available patient datasets (The Cancer Genome Atlas (TCGA)), we constructed transcriptomic correlations between gene DDR1, with an expression of genes for EGFR, ERBB2-4, mitogen-activated protein kinase (MAPK) pathway intermediates, BCR, and ABL and genes for cancer stem cell reactivation, cell polarity, and adhesion; we identified a positive association of DDR1 with EGFR, ERBB2, BRAF, SOX9, and VANGL2 in Pan-Cancer. The evaluation of the pathway network using the STRING database and Pathway Commons database revealed DDR1 protein to relay its signaling via adaptor proteins (SHC1, GRB2, and SOS1) and BCR axis to contribute to the KRAS-PI3K-AKT signaling cascade, which was confirmed by Western blotting. We further confirmed the cytotoxic potential of our lead combination involving EGFR/ERBB2 inhibitor (lapatinib) with DDR1/BCR-ABL inhibitor (nilotinib) in radioresistant spheroids of HCT116 (COAD) and, in an additional devastating primary cancer model, glioblastoma (GBM). GBMs overexpress DDR1 and share some common genomic features with COAD like EGFR amplification and WNT activation. Moreover, genetic alterations in genes like NF1 make GBMs have an intrinsically high KRAS activity. We show the combination of nilotinib plus lapatinib to exhibit more potent cytotoxic efficacy than either of the drugs administered alone in tumoroids of patient-derived recurrent GBMs. Collectively, our findings suggest that combinatorial targeting of DDR1/BCR-ABL with EGFR-ERBB2 signaling may offer a therapeutic strategy against stem-like KRAS-driven chemoradioresistant tumors of COAD and GBM, widening the window for its applications in mainstream cancer therapeutics.