Professional Education

  • Bachelor of Science, University of Hawaii Manoa (2014)
  • Doctor of Philosophy, Baylor College Of Medicine (2022)
  • Doctor of Philosophy, Baylor College of Medicine, Translational Biology and Molecular Medicine (2022)
  • Bachelor of Science, University of Hawaii at Manoa, Molecular Cell Biology (2014)

Stanford Advisors

All Publications

  • Cell death-induced immunogenicity enhances chemoimmunotherapeutic response by converting immune-excluded into T-cell inflamed bladder tumors NATURE COMMUNICATIONS Nikolos, F., Hayashi, K., Hoi, X., Alonzo, M., Mo, Q., Kasabyan, A., Furuya, H., Trepel, J., Di Vizio, D., Guarnerio, J., Theodorescu, D., Rosser, C., Apolo, A., Galsky, M., Chan, K. 2022; 13 (1): 1487


    Chemoimmunotherapy has recently failed to demonstrate significant clinical benefit in advanced bladder cancer patients; and the mechanism(s) underlying such suboptimal response remain elusive. To date, most studies have focused on tumor-intrinsic properties that render them "immune-excluded". Here, we explore an alternative, drug-induced mechanism that impedes therapeutic response via disrupting the onset of immunogenic cell death. Using two immune-excluded syngeneic mouse models of muscle-invasive bladder cancer (MIBC), we show that platinum-based chemotherapy diminishes CD8+ T cell tumor infiltration and constraines their antitumoral activity, despite expression of activation markers IFNγ and granzyme B. Mechanistically, chemotherapy induces the release of prostaglandin E2 (PGE2) from dying cancer cells, which is an inhibitory damage-associated molecular pattern (iDAMP) that hinderes dendritic cell maturation. Upon pharmaceutical blockade of PGE2 release, CD8+ T cells become tumoricidal and display an intraepithelial-infiltrating (or inflamed) pattern. This "iDAMP blockade" approach synergizes with chemotherapy and sensitizes bladder tumors towards anti-PD1 immune checkpoint inhibitor therapy. These findings provide a compelling rationale to evaluate this drug combination in future clinical trials.

    View details for DOI 10.1038/s41467-022-29026-9

    View details for Web of Science ID 000774213100016

    View details for PubMedID 35347124

  • Inhibitory DAMPs in immunogenic cell death and its clinical implications CELL STRESS Hayashi, K., Nikolos, F., Chan, K. S. 2021; 5 (4): 52-54


    Dying (or dead) cells are increasingly recognized to impose significant biological influence within their tissues of residence-exerting paracrine effects through proteins and metabolites that are expressed or secreted during cellular demise. For example, certain molecules function as potent mitogens, promoting the repopulation of neighboring epithelial cells. And other myriad of factors-classified as damage-associated molecular patterns (DAMPs)-function as "find me" (attractant), "eat me" (engulfment), or "danger" (activation) signals for recruiting and activating effector immune cells (e.g., dendritic cells) to initiate inflammation. Since the discovery of immunogenic cell death (ICD), the current dogma posits DAMPs as immunological adjuvants for innate immune cell mobilization and activation, which ultimately leads to the antitumoral cross-priming of CD8+ T cells. However, what is currently unknown is how these immunostimulatory DAMPs are counteracted to avoid immune-overactivation. Our recent work builds on these fundamentals and introduces prostaglandin E2 (PGE2) as an 'inhibitory' DAMP-a new variable to the ICD equation. Prostaglandin E2 functions as an immunosuppressive counterpoise of adjuvant DAMPs; and thus, mechanistically precludes ICD. Furthermore, the long-debated immunogenicity of gemcitabine chemotherapy was revealed to be contingent on inhibitory DAMP blockade and not due to its inability to promote DAMP expression (i.e., calreticulin) as previously reported. These findings were intriguing. First, despite the presence of gemcitabine-induced hallmark DAMPs, the inhibitory DAMP (i.e., PGE2) was sufficient to hinder the ICD-induced antitumoral immune response (Fig. 1a). And second, rather than pharmacologically substantiating immunostimulatory DAMPs as conventionally approached, the mitigation of the inhibitory DAMP-tipping the immunostimulatory and inhibitory DAMP balance in favor of immunostimulatory DAMPs-was sufficient to render the cell death immunogenic and converted gemcitabine into an ICD-inducing therapy (Fig. 1b). In this microreview, we extrapolate our findings and implicate the value of inhibitory DAMP(s) in drug discovery, its use for clinical prognosis, and as target(s) for therapeutic intervention.

    View details for DOI 10.15698/cst2021.04.247

    View details for Web of Science ID 000640079700002

    View details for PubMedID 33821233

    View details for PubMedCentralID PMC8012883

  • Tipping the immunostimulatory and inhibitory DAMP balance to harness immunogenic cell death NATURE COMMUNICATIONS Hayashi, K., Nikolos, F., Lee, Y. C., Jain, A., Tsouko, E., Gao, H., Kasabyan, A., Leung, H. E., Osipov, A., Jung, S. Y., Kurtova, A. V., Chan, K. S. 2020; 11 (1): 6299


    Induction of tumor cell death is the therapeutic goal for most anticancer drugs. Yet, a mode of drug-induced cell death, known as immunogenic cell death (ICD), can propagate antitumoral immunity to augment therapeutic efficacy. Currently, the molecular hallmark of ICD features the release of damage-associated molecular patterns (DAMPs) by dying cancer cells. Here, we show that gemcitabine, a standard chemotherapy for various solid tumors, triggers hallmark immunostimualtory DAMP release (e.g., calreticulin, HSP70, and HMGB1); however, is unable to induce ICD. Mechanistic studies reveal gemcitabine concurrently triggers prostaglandin E2 release as an inhibitory DAMP to counterpoise the adjuvanticity of immunostimulatory DAMPs. Pharmacological blockade of prostaglandin E2 biosythesis favors CD103+ dendritic cell activation that primes a Tc1-polarized CD8+ T cell response to bolster tumor rejection. Herein, we postulate that an intricate balance between immunostimulatory and inhibitory DAMPs could determine the outcome of drug-induced ICD and pose COX-2/prostaglandin E2 blockade as a strategy to harness ICD.

    View details for DOI 10.1038/s41467-020-19970-9

    View details for Web of Science ID 000598908500001

    View details for PubMedID 33288764

    View details for PubMedCentralID PMC7721802

  • Plasminogen activator inhibitor-2 (PAI-2) overexpression supports bladder cancer development in PAI-1 knockout mice in N-butyl-N- (4-hydroxybutyl)-nitrosamine- induced bladder cancer mouse model JOURNAL OF TRANSLATIONAL MEDICINE Furuya, H., Hayashi, K., Shimizu, Y., Kim, N., Tsukikawa, Y., Chen, R., Sun, Y., Chan, O. M., Pagano, I., Peres, R., Hokutan, K., Igari, F., Chan, K. S., Rosser, C. J. 2020; 18 (1): 57


    Accumulating evidence suggests that plasminogen activator inhibitor-1 (PAI-1) plays an important role in bladder tumorigenesis by regulating cell cycle. However, it remains unclear whether and how inhibition of PAI-1 suppresses bladder tumorigenesis.To elucidate the therapeutic effect of PAI-1 inhibition, we tested its tumorigenicity in PAI-1 knockout (KO) mice exposed to a known bladder carcinogen.PAI-1 deficiency did not inhibit carcinogen-induced bladder cancer in mice although carcinogen-exposed wild type mice significantly increased PAI-1 levels in bladder tissue, plasma and urine. We found that PAI-1 KO mice exposed to carcinogen tended to upregulate protein C inhibitor (PAI-3), urokinase-type plasminogen activator (uPA) and tissue-type PA (tPA), and significantly increased PAI-2, suggesting a potential compensatory function of these molecules when PAI-1 is abrogated. Subsequent studies employing gene expression microarray using mouse bladder tissues followed by post hoc bioinformatics analysis and validation experiments by qPCR and IHC demonstrated that SERPING1 is further downregulated in PAI-1 KO mice exposed to BBN, suggesting that SERPING1 as a potential missing factor that regulate PAI-2 overexpression (compensation pathway).These results indicate that serpin compensation pathway, specifically PAI-2 overexpression in this model, supports bladder cancer development when oncoprotein PAI-1 is deleted. Further investigations into PAI-1 are necessary in order to identify true potential targets for bladder cancer therapy.

    View details for DOI 10.1186/s12967-020-02239-6

    View details for Web of Science ID 000513873500003

    View details for PubMedID 32024545

    View details for PubMedCentralID PMC7003426

  • Collagen-rich airway smooth muscle cells are a metastatic niche for tumor colonization in the lung NATURE COMMUNICATIONS Lee, Y., Kurtova, A., Xiao, J., Nikolos, F., Hayashi, K., Tramel, Z., Jain, A., Chen, F., Chokshi, M., Lee, C., Bao, G., Zhang, X., Shen, J., Mo, Q., Jung, S., Rowley, D., Chan, K. 2019; 10: 2131


    Metastases account for the majority of cancer deaths. While certain steps of the metastatic cascade are well characterized, identification of targets to block this process remains a challenge. Host factors determining metastatic colonization to secondary organs are particularly important for exploration, as those might be shared among different cancer types. Here, we showed that bladder tumor cells expressing the collagen receptor, CD167a, responded to collagen I stimulation at the primary tumor to promote local invasion and utilized the same receptor to preferentially colonize at airway smooth muscle cells (ASMCs)-a rich source of collagen III in lung. Morphologically, COL3-CD167a-driven metastatic foci are uniquely distinct from typical lung alveolar metastatic lesions and exhibited activation of the CD167a-HSP90-Stat3 axis. Importantly, metastatic lung colonization could be abrogated using an investigational drug that attenuates Stat3 activity, implicating this seed-and-soil interaction as a therapeutic target for eliminating lung metastasis.

    View details for DOI 10.1038/s41467-019-09878-4

    View details for Web of Science ID 000467702800004

    View details for PubMedID 31086186

    View details for PubMedCentralID PMC6513865

  • Prognostic Power of a Tumor Differentiation Gene Signature for Bladder Urothelial Carcinomas JNCI-JOURNAL OF THE NATIONAL CANCER INSTITUTE Mo, Q., Nikolos, F., Chen, F., Tramel, Z., Lee, Y., Hayashi, K., Xiao, J., Shen, J., Chan, K. 2018; 110 (5): 448-459


    Muscle-invasive bladder cancers (MIBCs) cause approximately 150 000 deaths per year worldwide. Survival for MIBC patients is heterogeneous, with no clinically validated molecular markers that predict clinical outcome. Non-MIBCs (NMIBCs) generally have favorable outcome; however, a portion progress to MIBC. Hence, development of a prognostic tool that can guide decision-making is crucial for improving clinical management of bladder urothelial carcinomas.Tumor grade is defined by pathologic evaluation of tumor cell differentiation, and it often associates with clinical outcome. The current study extrapolates this conventional wisdom and combines it with molecular profiling. We developed an 18-gene signature that molecularly defines urothelial cellular differentiation, thus classifying MIBCs and NMIBCs into two subgroups: basal and differentiated. We evaluated the prognostic capability of this "tumor differentiation signature" and three other existing gene signatures including the The Cancer Genome Atlas (TCGA; 2707 genes), MD Anderson Cancer Center (MDA; 2252 genes/2697 probes), and University of North Carolina at Chapel Hill (UNC; 47 genes) using five gene expression data sets derived from MIBC and NMIBC patients. All statistical tests were two-sided.The tumor differentiation signature demonstrated consistency and statistical robustness toward stratifying MIBC patients into different overall survival outcomes (TCGA cohort 1, P = .03; MDA discovery, P = .009; MDA validation, P = .01), while the other signatures were not as consistent. In addition, we analyzed the progression (Ta/T1 progressing to ≥T2) probability of NMIBCs. NMIBC patients with a basal tumor differentiation signature associated with worse progression outcome (P = .008). Gene functional term enrichment and gene set enrichment analyses revealed that genes involved in the biologic process of immune response and inflammatory response are among the most elevated within basal bladder cancers, implicating them as candidates for immune checkpoint therapies.These results provide definitive evidence that a biology-prioritizing clustering methodology generates meaningful insights into patient stratification and reveals targetable molecular pathways to impact future therapeutic approach.

    View details for DOI 10.1093/jnci/djx243

    View details for Web of Science ID 000431896500005

    View details for PubMedID 29342309

    View details for PubMedCentralID PMC6279371