Breast
Sohini Khan, MD
Surgery Resident
Department of Surgery, University of California San Diego, La Jolla, CA
San Diego, California, United States
Sohini Khan, MD
Surgery Resident
Department of Surgery, University of California San Diego, La Jolla, CA
San Diego, California, United States
Sohini Khan, MD
Surgery Resident
Department of Surgery, University of California San Diego, La Jolla, CA
San Diego, California, United States
Jaimin R. Shah, MS
Graduate Researcher
Department of Chemistry and Biochemistry & Materials Science and Engineering, University of California San Diego, La Jolla, CA, United States
Tao Dong, MS
Graduate Researcher
Department of Chemistry and Biochemistry & NanoEngineering, University of California San Diego, La Jolla, CA, United States
Abraham T. Phung, MS
Graduate Researcher
Department of Chemistry and Biochemistry & NanoEngineering, University of California San Diego, La Jolla, CA, United States
Omonigho Aisagbonhi, MD
Assistant Clinical Professor
Department of Pathology, University of California San Diego, La Jolla, CA, United States
William C. Trogler, PhD
Emeritus Professor
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, United States
Sarah L. Blair, MD
Professor of Surgery
Division of Surgical Oncology, Department of Surgery, University of California San Diego, La Jolla, CA, United States
Andrew C. Kummel, PhD
Distinguished Professor
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, United States
Triple negative breast cancer (TNBC) is one of the most aggressive forms of breast cancer associated with poor prognosis despite aggressive therapy including surgery, radiation and chemotherapy. Immunotherapy is emerging as an important treatment adjunct in this population. Oncolytic adenoviruses have shown promise as an adjunct immunotherapy treatment option to boost immune stimulation; however, cellular entry typically highly depends on the Coxsackie adenovirus receptor (CAR). In the present study, liposomal encapsulation was employed as an effective delivery method for oncolytic adenoviruses in TNBC cells. Liposomal encapsulation was compared to naked oncolytic virus delivery to examine transduction efficiency and possible improved immune response in TNBC cell lines.
Methods:
Studies were performed in vitro in two cell lines – one murine and low CAR expressing (4T1) and one human and high CAR expressing (MD-MBA-231). Liposomes containing a GFP-expressing adenovirus (Ad-GFP) were used to transduce these cell lines to determine enhanced transduction efficiency attributed to liposomal coating. Fluorescence intensity was quantified using a plate reader; GFP-positive cells were visually identified with fluorescence microscopy. For MD-MBA-231 cells, liposomes containing replicating-competent Ad-DL309 adenovirus were used. Cell viability was measured by alamarBlue colorimetric assay and effectiveness of liposome-mediated cell lysis was used to determine transduction efficacy.
Results:
Liposome encapsulation of Ad-GFP significantly improved transduction efficiency compared to unencapsulated Ad-GFP in both 4T1 cells (p=0.0024, Fig 1A and B) and MD-MBA-231 cells (p=0.00004, Fig 1C). Further, transducing the human TNBC cell line with Ad-DL309 significantly enhanced cancer cell lysis when encapsulated as shown by the alamarBlue cell viability assay (p=0.0003, Fig 1D).
Conclusions:
Liposomal oncolytic adenovirus has been shown to be a promising tool and we have identified its use as a novel delivery agent for TNBC. Liposomal encapsulation improves transduction efficiency and cell lysis. Future in vivo studies will assess the potential benefits of encapsulation in enhancing oncolytic activity and immune system stimulation when intratumorally administering TNBC tumor-bearing mice with liposomal oncolytic adenovirus and assessing for post-resection recurrence and spread. Given it was shown that liposomal encapsulation improves transduction efficiency even in low CAR expressing cells, its novel utility can apply to other tumor types, as well.