CD۴۷ and SIGLEC۱۵ Immune Checkpoint Genes Expression and Apoptotic Pathway Activation Following Photodynamic Therapy with Zinc Phthalocyanine in the B-CPAP Thyroid Cancer Cell Line

Background & Objectives: Thyroid cancer is one of the most prevalent endocrine malignancies. Photodynamic therapy is an emerging minimally invasive therapeutic modality that employs a photosensitizer in conjunction with light irradiation to induce targeted cytotoxicity. The present study was designed to evaluate the effects of zinc phthalocyanine-mediated photodynamic therapy on the expression of immune checkpoint genes CD۴۷ and SIGLEC۱۵, as well as key genes involved in apoptotic pathways, in papillary thyroid cancer cells. Materials & Methods: The human papillary thyroid cancer cell line B-CPAP was exposed to various concentrations of zinc phthalocyanine and subsequently irradiated using a ۶۷۵ nm diode laser at a fluence of ۲۴ J/cm². Cellular viability, reflecting mitochondrial metabolic activity, was assessed using the MTT assay. The relative mRNA expression levels of CD۴۷, SIGLEC۱۵, Caspase-۳, Caspase-۹ and Bcl-۲ genes were quantified using quantitative real-time polymerase chain reaction. Results:  Zinc phthalocyanine-mediated photodynamic therapy markedly reduced the viability of B-CPAP cells. The treatment activated the intrinsic apoptotic pathway, as demonstrated by the significant upregulation of Caspase-۳ and Caspase-۹ transcripts alongside the downregulation of Bcl-۲ expression. In addition, a statistically significant reduction in the mRNA expression levels of the immune checkpoint molecules CD۴۷ and SIGLEC۱۵ was observed following treatment. Conclusion:  The findings of this study provide novel evidence that zinc phthalocyanine-mediated photodynamic therapy simultaneously induces apoptosis while downregulating the critical immune checkpoints CD۴۷ and SIGLEC۱۵ in thyroid cancer cells. This dual mechanism of action underscores the therapeutic potential of photodynamic therapy as an effective strategy for enhancing antitumor efficacy through both direct cytotoxic effects and the potential mitigation of immune evasion. Keywords: Thyroid cancer, Photodynamic therapy, Zinc phthalocyanine, Immune checkpoints, Apoptosis CD۴۷ and SIGLEC۱۵ Immune Checkpoint Genes Expression and Apoptotic Pathway Activation Following Photodynamic Therapy with Zinc Phthalocyanine in the B-CPAP Thyroid Cancer Cell Line Photodynamic Therapy, Immune Checkpoints, and Apoptosis in Thyroid Cancer Background & Objectives: Thyroid cancer is one of the most prevalent endocrine malignancies. Photodynamic therapy is an emerging minimally invasive therapeutic modality that employs a photosensitizer in conjunction with light irradiation to induce targeted cytotoxicity. The present study was designed to evaluate the effects of zinc phthalocyanine-mediated photodynamic therapy on the expression of immune checkpoint genes CD۴۷ and SIGLEC۱۵, as well as key genes involved in apoptotic pathways, in papillary thyroid cancer cells. Materials & Methods: The human papillary thyroid cancer cell line B-CPAP was exposed to various concentrations of zinc phthalocyanine and subsequently irradiated using a ۶۷۵ nm diode laser at a fluence of ۲۴ J/cm². Cellular viability, reflecting mitochondrial metabolic activity, was assessed using the MTT assay. The relative mRNA expression levels of CD۴۷, SIGLEC۱۵, Caspase-۳, Caspase-۹ and Bcl-۲ genes were quantified using quantitative real-time polymerase chain reaction. Results:  Zinc phthalocyanine-mediated photodynamic therapy markedly reduced the viability of B-CPAP cells. The treatment activated the intrinsic apoptotic pathway, as demonstrated by the significant upregulation of Caspase-۳ and Caspase-۹ transcripts alongside the downregulation of Bcl-۲ expression. In addition, a statistically significant reduction in the mRNA expression levels of the immune checkpoint molecules CD۴۷ and SIGLEC۱۵ was observed following treatment. Conclusion:  The findings of this study provide novel evidence that zinc phthalocyanine-mediated photodynamic therapy simultaneously induces apoptosis while downregulating the critical immune checkpoints CD۴۷ and SIGLEC۱۵ in thyroid cancer cells. This dual mechanism of action underscores the therapeutic potential of photodynamic therapy as an effective strategy for enhancing antitumor efficacy through both direct cytotoxic effects and the potential mitigation of immune evasion. Keywords:

کلیدواژه ها:

Thyroid cancer ، Photodynamic therapy ، Zinc phthalocyanine ، Immune checkpoints ، Apoptosis