Combination of Tipifarnib and Sunitinib Overcomes Renal Cell Carcinoma Resistance to Tyrosine Kinase Inhibitors via Tumor-Derived Exosome and T Cell Modulation

Jacob W Greenberg; Hogyoung Kim; Miae Ahn; Ahmed A Moustafa; He Zhou; Pedro C Barata; A Hamid Boulares; Asim B Abdel-Mageed; Louis S Krane

doi:10.3390/cancers14040903

Combination of Tipifarnib and Sunitinib Overcomes Renal Cell Carcinoma Resistance to Tyrosine Kinase Inhibitors via Tumor-Derived Exosome and T Cell Modulation

Cancers (Basel). 2022 Feb 11;14(4):903. doi: 10.3390/cancers14040903.

Authors

Jacob W Greenberg¹, Hogyoung Kim¹, Miae Ahn¹, Ahmed A Moustafa^{1

2}, He Zhou³, Pedro C Barata⁴, A Hamid Boulares⁵, Asim B Abdel-Mageed^{1

5

6

7}, Louis S Krane^{1

8}

Affiliations

¹ Department of Urology, Tulane University School of Medicine, New Orleans, LA 70012, USA.
² Department of Zoology and Entomology, Faculty of Science, Helwan University, Cairo 11790, Egypt.
³ Department of Physiology & Internal Medicine, Section of Nephrology, Tulane University School of Medicine, New Orleans, LA 70012, USA.
⁴ Department of Internal Medicine, Section of Hematology/Oncology, Tulane University School of Medicine, New Orleans, LA 70012, USA.
⁵ The Stanley Scott Cancer Center, Ouisiana Cancer Research Center, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
⁶ Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70012, USA.
⁷ Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA.
⁸ Southeastern Louisiana Veterans Health Care System, New Orleans, LA 70119, USA.

Abstract

Background: Tyrosine kinase inhibitors (TKI) were initially demonstrated as an efficacious treatment for renal cell carcinoma (RCC). However, after a median treatment length of 14 months, a vast majority of patients develop resistance. This study analyzed a combination therapy of tipifarnib (Tipi) + sunitinib that targeted exosome-conferred drug resistance.

Methods: 786-O, 786-O-SR (sunitinib resistant), A498, A498-SR, Caki-2, Caki-2-SR, and 293T cells were cultured. Exosomes were collected using differential ultracentrifugation. Cell proliferation, Jurkat T cell immune assay, and immunoblot analysis were used for downstream analysis.

Results: SR exosomes treatment displayed a cytotoxic effect on immune cells. This cytotoxic effect was associated with increased expression of PD-L1 on SR exosomes when compared to sunitinib-sensitive (SS) exosomes. Additionally, Tipi treatment downregulated PD-L1 expression on exosomes derived from SR cell lines. Tipi's ability to downregulate PD-L1 in exosomes has a significant application within patients. Exosomes collected from patients with RCC showed increased PD-L1 expression over subjects without RCC. Next, exosome concentrations were then compared after Tipi treatment, with all SS cell lines displaying an even greater reduction. On immunoblot assay, 293T cells showed a dose-dependent increase in Alix with no change in either nSMase or Rab27a. Conversely, all the SS and SR cell lines displayed a decrease in all three markers. After a cell proliferation employed a 48-h treatment on all SS and SR cell lines, the drug combination displayed synergistic ability to decrease tumor growth.

Conclusions: Tipifarnib attenuates both the exosome endosomal sorting complex required for endosomal sorting complex required for transport (ESCRT)-dependent and ESCRT-independent pathways, thereby blocking exosome biogenesis and secretion as well as downregulating PD-L1 on SS and SR cells.

Keywords: ERK pathway; PD-L1; TKI resistance; cell culture; exosomes; extracellular vesicles; renal cell carcinoma; resistance; sunitinib; tipifarnib.

Abstract

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