2021 Early Career Investigator Grant Recipient — Ichiko Kinjyo, MD, PhD

Ichiko Kinjyo, MD, PhD

University of New Mexico

A Novel Mechanism for the Immunomodulatory Effects of PARP-inhibitor

Project Summary

Poly (ADP-ribose) polymerase (PARP)-inhibitors are an emerging class of medicines for women with recurrent ovarian cancer and improving patients’ prognosis. PARP-inhibitors became the first effective and tolerable maintenance treatment after surgery and chemotherapy to prevent a recurrence. The main mechanisms of action for the treatment benefit is based on targeting cancer cells and inducing cancer cell death. It has been studies that cancer develops the strategies to escape from the host immune system and grow invasively. The idea to boost immune activity against cancer has become a very promising treatment approach in the combination of chemotherapies.

Through many clinical trials and basic research, the evidence that PARP-inhibitors can enhance cancer-immunity is accumulating. Recently, pairing PARP-inhibitors with immunostimulatory drugs which can boost the anti-cancer immune system’s ability to fight cancer is a very attractive idea. Although several clinical trials are going on now, how PARP inhibitors directly impact on host immune system is not clear yet. In this proposal, we aim to examine the effects of PARP-inhibitor on immune cells, especially their anti-cancer T-lymphocytes. T-lymphocytes are circulating the whole body to surveillance and once they come across targets, such as invading pathogens or cancerous cells, they start to proliferate and differentiate into professional killing cells. The process requires high cellular energy and causes a lot of stress in T-lymphocytes. We will address how PARP-inhibitors impact such a process to develop an anti-cancer activity. Our hypothesis is PARP-inhibitors support the energy metabolism in T-lymphocytes for the successful development of effector T cell subset. We will examine how the proliferation and differentiation of T-lymphocytes can be changed by PARP-inhibitors by analyzing the number of cell divisions, anti-tumor activity and metabolic markers in T-lymphocytes. The cancer control efficacy will be tested by measuring the cancer growth and survival of ovarian cancer mice models.

The results from our research will add new knowledge to optimize the current clinical treatment protocol of PARP-inhibitors for the combination with immunomodulatory agents. Our long-term goal is to find the effective combination treatment with PARP-inhibitors for long-lasting anti-cancer immune activity in patients with ovarian cancer and potentially other types of cancers.

Bio

Ichiko Kinjyo MD PhD, is a Research Assistant Professor of Molecular Medicine at the University of New Mexico and Comprehensive Cancer Center. She obtained her medical degree from Kagoshi-ma University (Japan) and completed 2 years-clinical training at Okinawa Prefectural Chubu Hospi-tal. She received a fellowship from the Japanese government to complete a PhD in Molecular Cel-lular Immunology at Kyushu University (Japan), with research about the immune regulation by sup-pressors of cytokine signaling (SOCS) family under the mentorship of Dr. Akihiko Yoshimura. She pursued postdoctoral training in the laboratory of Dr. Steven L Reiner at the University of Pennsyl-vania, where she learned T cell immunology through the research about T cell fate determination. After rejoining Dr. Yoshimura’s lab at Keio University (Japan), she conducted additional postdoctor-al research about the cell cycle progression during CD8 T cell differentiation in Dr. Wolfgang We-ninger’s lab at the University of Sydney. In 2013, she moved back to the USA and joined Dr. Bridget S Wilson’s lab at the University of New Mexico in Albuquerque and studied the immunotoxin-based treatment against acute lymphoblastic leukemia and determined the novel mechanisms for leuke-mia metastasis into the central nervous system. In 2017, she started to work with an excellent OB/GYN clinical researcher; Dr. Sarah F Adams MD, PhD, to extend the benefits of the novel combination treatment with PARP-inhibitors and immune checkpoint blockade in patients with ovari-an cancer. Her continuous interests in T cell biology have been inspired her toward cancer immu-notherapy to reactivate anti-tumor T cells against ovarian cancers.