Hypericin-Based Photodynamic Therapy Displays Higher Selectivity and Phototoxicity towards Melanoma and Squamous Cell Cancer Compared to Normal Keratinocytes In Vitro

Sep 24, 2026

Explore hypericin as a naturally occurring photosensitizer for photodynamic therapy (PDT) in skin cancer, focusing on phototoxic effects and mechanisms versus normal keratinocytes. Cancer cell models (SCC-25 and MUG-Mel2) and HaCaT were treated with 0.1–40 μM hypericin, incubated for 24 h, then irradiated with orange light (3.6 or 7.2 J/cm²). Phototoxicity was evaluated by MTT and SRB, cellular uptake by flow cytometry, and apoptosis by TUNEL. Hypericin showed higher phototoxicity in cancer cells, with increased selective uptake and proapoptotic effects after PDT, supporting hypericin-based PDT as a promising, less invasive skin-cancer approach.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Introduction

Hypericin and its pharmacological background

PDT mechanism and therapeutic parameters

Methods and assessment approach

Hypericin treatment and irradiation settings

Phototoxicity, uptake, and apoptosis assays

Results and implications

Selective phototoxicity and uptake in cancer cells

Observed apoptosis after PDT

Conclusion

Article Hypericin-Based Photodynamic Therapy Displays Higher Selectivity and Phototoxicity towards Melanoma and Squamous Cell Cancer Compared to Normal Keratinocytes In Vitro Marta Wo´zniak * and Martyna Nowak-Perlak Citation: Wo´zniak, M.; NowakPerlak, M. Hypericin-Based Photodynamic Therapy Displays Higher Selectivity and Phototoxicity towards Melanoma and Squamous Cell Cancer Compared to Normal Keratinocytes In Vitro. Int. J. Mol. Sci. 2023, 24, 16897. [https://doi.org/](https://doi.org/)[ ](https://doi.org/)[10.3390/ijms242316897](10.3390/ijms242316897) Academic Editors: Shun-Fa Yang and Ming-Hsien Chien Received: 23 October 2023 Revised: 24 November 2023 Accepted: 27 November 2023 Published: 29 November 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([https://](https://)[ ](https://)[creativecommons.org/licenses/by/](creativecommons.org/licenses/by/)[ ](creativecommons.org/licenses/by/)[4.0/](4.0/)) . Department of Clinical and Experimental Pathology, Division of General and Experimental Pathology, Wroclaw Medical University, 50-368 Wroclaw, Poland; [martyna.nowak-perlak@student.umw.edu.pl](martyna.nowak-perlak@student.umw.edu.pl) * [Correspondence: marta.wozniak@umw.edu.pl](Correspondence: marta.wozniak@umw.edu.pl) Abstract: The aim of this study was to explore the potential of hypericin, a naturally occurring photosensi-tizer, for photodynamic therapy (PDT) in skin cancer, investigating its phototoxic effects and mechanisms of action in cancer cells compared to normal skin keratinocytes, squamous cell cancer (SCC-25) cells and melanoma (MUG-Mel2) cells. Hypericin was applied at concentrations ranging from 0.1–40 􀀖M to HaCaT, SCC-25, and MUG-Mel2 cells. After 24 h of incubation, the cells were exposed to orange light at 3.6 J/cm2 or 7.2 J/cm2 . Phototoxicity was assessed using MTT and SRB tests. Cellular uptake was measured by ﬂow cytometry. Apoptosis-positive cells were estimated through TUNEL for apoptotic bodies' visualization. Hypericin exhibited a higher phototoxic reaction in cancer cells compared to normal keratinocytes after irradiation. Cancer cells demonstrated increased and selective uptake of hypericin. Apoptosis was observed in SCC-25 and MUG-Mel2 cells following PDT. Our ﬁndings suggest that hypericin-based PDT is a promising and less invasive approach for treating skin cancer. The higher phototoxic reaction, selective uptake by cancer cells, and observed proapoptotic properties support the promising role of hypericin-based PDT in skin cancer treatment. Keywords: hypericin; photodynamic therapy; natural photosensitizer; skin cancer; melanoma; squamous cell cancer 1. Introduction Hypericin is a natural compound extracted from Hypericum perforatum [1,2] . It exhibits various pharmacological effects, such as anti-depressive, anti-tumor, anti-inﬂammatory, and antiviral activity [3,4] . Several studies have demonstrated its high tumor-speciﬁccytotoxicity, coupled with minimal side effects. Another beneﬁt of this natural compound in tumor treatment is its ability to stimulate the generation of reactive oxygen species (ROS) . Hypericin can also activate the caspase-dependent pathway, which leads to the death of cancer cells [2] . Hypericin mainly accumulates in the membranes of the endoplasmic reticulum, lysosomes, Golgi apparatus, and mitochondria due to its hydrophobic character. It has been recognized as one of the most effective photodynamic therapy (PDT) molecules [5,6] . Photodynamic therapy is a technique that uses a photosensitizer and light of a speciﬁc wavelength to speciﬁcally eliminate cancer cells in the body. The success of this therapy is determined by a variety of parameters, including the type of cancer cells, the photosensitizer (PS) applied, and the wavelength of light used for the treatment [7–9] . The mec

FAQs

What is the main goal of this study?

To evaluate hypericin as a photosensitizer for photodynamic therapy in skin cancer by comparing phototoxic effects and underlying mechanisms in cancer cells versus normal keratinocytes.

How were the cells treated and irradiated?

Cells were incubated with hypericin at 0.1–40 μM for 24 hours, then exposed to orange light at 3.6 J/cm² or 7.2 J/cm².

Which assays were used to measure phototoxicity, uptake, and apoptosis?

Phototoxicity was assessed with MTT and SRB tests, cellular uptake was measured by flow cytometry, and apoptosis-positive cells were estimated using TUNEL to visualize apoptotic bodies.

Sep 24, 2026

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