Targeting Senescent Tumor Cells in Cancer Immunotherapy [May. 12, 2026] DOJINDO LABORATORIES

Senescent cancer cells can persist after treatment and affect tumor control, it is important to understand their role in immune evasion for therapeutically relevant. One recent study showed that therapy-induced senescent cancer cells upregulate PD-L1 through transcriptional regulation and RPN1-dependent glycosylation, enabling immune evasion and tumor regrowth. Another study developed a SA-β-gal-responsive agent that binds PD-L1 for cellular uptake, accumulates in lysosomes of senescent tumor cells, and reduces immunosuppressive signaling while promoting antitumor responses. Together, these findings highlight senescent tumor cells as a relevant focus in cancer immunotherapy research.

Therapy-induced senescent cancer cells contribute to cancer progression by promoting ribophorin 1-dependent PD-L1 upregulation (Nature Communications, 2025)
Summary:
This study investigated why therapy-induced senescent cancer cells persist after treatment and drive tumor recurrence. These cells upregulate PD-L1 through two mechanisms: increased transcription and RPN1-dependent glycosylation, which stabilizes membrane PD-L1 and enables immune evasion from T-cells.

Highlighted technique:
When RPN1, a candidate regulator of PD-L1 glycosylation, was suppressed, PD-L1 levels decreased. To confirm this reflected direct regulation rather than a reduced proportion of senescent cells, SA-β-Gal activity staining was used to quantify the senescent cell population.

Fluorescent SA-β-Gal detection dye enables co-staining and quantitative analysis of cellular senescence by fluorescence microscopy or flow cytometry.

Chemical anchoring of immunotherapeutic drugs within senescent tumor cells overcomes senescence-driven immunotherapy resistance (Nature Communications, 2026)
Summary:
This study developed DN-Ghcy to overcome immunotherapy resistance in therapy-induced senescent tumor cells. The compound binds PD-L1 to facilitate cellular uptake and is retained in lysosomes through SA-β-gal-dependent activation. This mechanism reduces immunosuppressive SASP signaling, counteracts drug efflux and PD-L1-mediated immune evasion, and promotes antitumor immunity.

Highlighted technique:
To determine whether lysosomal DN-Ghcy retention compromises lysosomal membrane integrity in senescent tumor cells, the authors assessed lysosomal localization, drug retention, membrane permeabilization via fluorescent dextran release, and immunogenic cell death via extracellular ATP release in 2D senescent 4T1 cells.

For evaluating cell damage-associated responses, an extracellular ATP assay kit is available and can be measured reproducibly using a detailed protocol. For lysosomal analysis, there are pH-independent dye and pH-sensitive dye, combining these dyes enables a more detailed evaluation of lysosomal function in terms of pH changes and lysosomal quantity.

Application Note
> Senescent Cells Lose Mitochondrial Activity

NAD(+) levels decline during the aging process, causing defects in nuclear and mitochondrial functions and resulting in many age-associated pathologies*. Here, we try to redemonstrate this phenomenon in the doxorubicin (DOX)-induced cellular senescence model with a comprehensive analysis of our products.

*S. Imai, et al., Trends Cell Biol, 2014, 24, 464-471

Products in Use
① DNA Damage Detection Kit - γH2AX
② Cellular Senescence Detection Kit - SPiDER-βGal
③ NAD/NADH Assay Kit-WST
④ JC-1 MitoMP Detection Kit
⑤ Glycolysis/OXPHOS Assay Kit、Lactate Assay Kit-WST

Senescence, Lysosome and Oxidative stress Indicators

Target	Kit & Probes
Senescence-associated β-gal detection	SPiDER-βGal for live-cell imaging or flow cytometry / microplate reader / tissue samples Blue cellular senescence detection dye for fixed cells, SPiDER Blue
Lysosomal Function Analysis Kit	Lysosomal Acidic pH Detection Kit -Green/Red and Green/Deep Red
High Specific Lysosommal Mass Detection	LysoPrime Green / Deep Red
Lysosomal Acidic pH Detection	pHLys Red
Total ROS detection	Highly sensitive DCFH-DA or Photo-oxidation Resistant DCFH-DA
Cell proliferation/ cytotoxicity assay	Cell Counting Kit-8 and Cytotoxicity LDH Assay Kit-WST