Publication Date

2019-12-17

Availability

Embargoed

Embargo Period

2021-12-16

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Cancer Biology (Medicine)

Date of Defense

2019-12-05

First Committee Member

Vinata B. Lokeshwar

Second Committee Member

Karoline Briegel

Third Committee Member

Enrique A. Mesri

Fourth Committee Member

Richard K. Lee

Abstract

Bladder cancer (BCa) is the 4th most common cancer in men, and more often presents as advanced disease in women. Management of BCa is complicated and costly due to high rates of recurrence and progression, multifocality, and heterogeneity of tumors. The hyaluronic acid-HYAL-1 system is a molecular driver of BCa. Tumor cell-derived hyaluronidase, HYAL-1, degrades hyaluronic acid (HA) into angiogenic fragments (AGF: 10-12 disaccharides). AGF support tumor growth and progression. In preclinical models of BCa, we evaluated whether o-sulfated AGF (sHA-F) inhibits HYAL-1 HAase activity and has antitumor activity. At IC50 for HAase activity inhibition (5-20 µg/ml [0.4-1.7 µM]), sHA-F significantly inhibited proliferation, motility and invasion of HYAL-1 expressing BCa cells (253J-Lung, HT1376, UMUC-3), P Metastatic renal cell carcinoma (mRCC) is a fatal disease. About 30% of patients are diagnosed with mRCC, and another 30% develop mRCC despite surgical resection of primary tumors. Purpose: Therapeutic strategies that overcome resistance to modestly effective FDA-approved drugs such as sorafenib (SF) could improve outcome in metastatic renal cell carcinoma (mRCC) patients. We discovered a mechanism of SF inefficacy and employed 4-methylumbelliferone (MU) and SF combination as a targeted treatment. We analyzed UDP-glucuronosyltransferase-1A9 (A9) expression in a clinical-cohort (51 normal; 83 tumor), RCC TCGA-dataset (TCGA-cohort; n=542), RCC cells, and in microsomes from normal kidney and tumor tissues. SF+MU combination was evaluated in empty vector (EV), A9-overexpressing and A9-shRNA transfectants of RCC cells, patient-derived tumor-spheroids, RCC-endothelial cell co-cultures and xenograft (subcutaneous; orthotopic). SF is terminally biotransformed by A9-mediated glucuronidation. In the clinical and TCGA cohorts, A9 transcript levels were elevated in RCC specimens and independently predicted metastasis and overall-survival (P<0.0001). In microsomes, A9 protein levels were ~10-fold elevated in patients who developed metastasis. MU downregulated A9 levels, and consequently, SF-glucuroniation was inhibited at low-dose SF+MU combination. SF+MU combinations inhibited growth, clonogenic survival, and motility/invasion of EV-transfectants, EV-endothelial cell co-cultures, and patient-derived tumor-spheroids (80%-98%; P<0.001). SF+MU also downregulated mediators of invasion/metastasis. While A9-transfectants were resistant to SF+MU, A9-shRNA cells were sensitive to SF. Subcutaneous EV and A9 tumors were angiogenic, and invaded skeletal muscle and subcutaneous fat. Orthotopic EV- and A9- kidney tumors metastasized to distant organs within 4-5-weeks. In both models, oral administration of SF+MU inhibited tumor growth and abrogated metastasis only in the EV-group. A9-overexpression is likely a contributor to SF failure in mRCC. By downregulating A9 levels, SF+MU combination offers an effective oral treatment for mRCC.

Keywords

Sorafenib; 4-methylumbelliferone; UGT1A9; Renal cell carcinoma; Sulfated hyaluronic acid; Bladder cancer

Available for download on Thursday, December 16, 2021

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