Role of the p53­TRPM1/miR­211­MMP9 axis in UVB­induced human melanocyte migration and its potential in repigmentation.

Clinical studies have proven that ultraviolet B (UVB) based phototherapy can induce perifollicular and marginal repigmentation patterns in the skin of vitiligo patients. It is, however, difficult to conceive how melanocytes can easily exit from their tightly interconnected epidermal microenvironment to re­enter a different location in the skin to establish a new network with neighboring keratinocytes. While it is known that matrix metalloprotease 9 (MMP9) is involved in the degradation of the extracellular matrix in physiological or pathological processes, little is known about whether MMP9 affects melanocyte migration in vitiligo repigmentation. To investigate the effects of the p53­ transient receptor potential cation channel subfamily M member 1 (TRPM1)/microRNA (miR/miRNA)­211­MMP9 axis to regulate melanocyte migration following exposure to UVB, the expression profile of MMP9 in cultured human melanocytes transfected with or without the miR­211­mimic and p53­GFP lentiviral vector, respectively were determined. Quantitative polymerase chain reaction and western blotting were used to examine p53, TRPM1 and MMP9 mRNA and protein levels in UVB­exposed and unexposed cells. The capacity of melanocytes to migrate on collagen IV substrate was estimated using a Transwell migration assay. Interestingly, the upregulation of p53 and MMP9 at the mRNA and protein levels was evident in melanocytes treated with single or repeat exposures to UVB, whereas levels of TRPM1 and miR­211 were significantly suppressed in UVB­exposed melanocytes compared with the UVB­unexposed control cells. These results indicate that the p53­TRPM1/miR­211­MMP9 axis is significantly activated in melanocytes exposed to UVB. Notably, the ability of melanocyte migration was altered by the overexpression of p53 using a lentiviral vector and by the upregulation of miR­211 using an miRNA mimic. That altered migration could be neutralized by co­treatment with GM6001 (a broad­spectrum MMP inhibitor). Overall, these results show that the MMP9­mediated migration of melanocytes is regulated by a novel mechanism driven by the p53­TRPM1/miR­211­MMP9 axis. Activation of the p53­TRPM1/miR­211­MMP9 axis potentially represents an attractive therapeutic target to improve repigmentation outcomes in vitiligo patients.

Degraded melanocores are incompetent to protect epidermal keratinocytes against UV damage.

Melanosomes are membrane-bound intracellular organelles that are uniquely generated by melanocytes (MCs) in the basal layer of human epidermis. Highly pigmented mature melanosomes are transferred from MCs to keratinocytes (KCs), and then positioned in the supra-nuclear region to ensure protection against ultraviolet radiation (UVR). However, the molecular mechanism underlying melanosome (or melanin pigment) transfer remains enigmatic. Emerging evidence shows that exo-/endo-cytosis of the melanosome core (termed melanocore) has been considered as the main transfer manner between MCs and KCs. As KCs in the skin migrate up from the basal layer and undergo terminal differentiation, the melanocores they have taken up from MCs are subjected to degradation. In this study, we isolated individual melanocores from human MCs in culture and then induced their destruction/disruption using a physical approach. The results demonstrate that the ultrastructural integrity of melanocores is essential for their antioxidant and photoprotective properties. In addition, we also show that cathepsin V (CTSV), a lysosomal acid protease, is involved in melanocore degradation in calcium-induced differentiated KCs and is also suppressed in KCs following exposure to UVA or UVB radiation. Thus, our study demonstrates that change in the proportion of melanocores in the intact/undegraded state by CTSV-related degradation in KCs affects photoprotection of the skin.

Induction of retinal-dependent calcium influx in human melanocytes by UVA or UVB radiation contributes to the stimulation of melanosome transfer.

OBJECTIVES: The transfer of melanosomes from melanocytes to neighbouring keratinocytes is critical to protect the skin from the deleterious effects of ultraviolet A (UVA) and ultraviolet B (UVB) irradiation; however, the initial factor(s) that stimulates melanosome transfer remains unclear. In this study, we investigated the induction of retinal-dependent calcium (Ca2+ ) influx in melanocytes (MCs) by UVA or UVB irradiation and the effect of transient receptor potential cation channel subfamily M member 1 (TRPM1) (melastatin1)-related Ca2+ influx on melanosome transfer. MATERIALS AND METHODS: Primary human epidermal MCs were exposed to physiological doses of UVB or UVA light and loaded with a calcium indicator Fluo-4 dye. The change of intracellular calcium of MCs was monitored using a two-photon confocal fluorescence microscopy. MCs were co-cultured with human epidermal keratinocytes (KCs) in the absence or presence of voriconazole (a TRPM1 blocker) or calcium chelators. MCs were also transfected with TRPM1 siRNA for silencing the expression of TRPM1 gene. The melanosome transfer in the co-cultured cells was quantitatively analysed using flow cytometry and was further confirmed by immunofluorescent double-staining. The protein levels and distributions of TRPM1, OPN3 and OPN5 in MCs were measured by Western blotting or immunofluorescent staining. RESULTS: The retinal-dependent Ca2+ influx of UVA-exposed melanocytes differed greatly from that of UVB-exposed melanocytes in the timing-phase. The protein expression of TRPM1 in mono- and co-cultured MCs was dose-dependently up-regulated by UVA and UVB. TRPM1 siRNA-mediated knockdown and the blockage of TRPM1 channel using a putative antagonist (voriconazole) significantly inhibited melanosome transfer in co-cultures following UVA or UVB exposure. CONCLUSIONS: The distinct time-phases of Ca2+ influx in MCs induced by UVA or UVB contribute to the consecutive stimulation of melanosome transfer, thereby providing a potent photoprotection against harmful UV radiation.

Deoxyarbutin Possesses a Potent Skin-Lightening Capacity with No Discernible Cytotoxicity against Melanosomes.

Safe and effective ingredients capable of removing undesired hyperpigmentation from facial skin are urgently needed for both pharmaceutical and cosmetic purposes. Deoxyarbutin (4-[(tetrahydro-2H-pyran-2-yl) oxy] phenol, D-Arb) is a glucoside derivative of hydroquinone. Here, we investigated the toxicity and efficacy of D-Arb at the sub-cellular level (directly on melanosomes) and skin pigmentation using in vivo and in vitro models to compare with its parent compound hydroquinone (1,4-benzenediol, HQ). At first, we examined the ultrastructural changes of melanosomes in hyperpigmented guinea pig skin induced by 308-nm monochromatic excimer lightand/or treated with HQ and D-Arb using transmission electron microscopy. The results showed that prominent changes in the melanosomal membrane, such as bulb-like structure and even complete rupture of the outer membranes, were found in the skin after topical application of 5% HQ for 10 days. These changes were barely observed in the skin treated with D-Arb. To further clarify whether membrane toxicity of HQ was a direct result of the compound treatment, we also examinedultrastructural changes of individual melanosomes purified from MNT1 human melanoma cells. Similar observations were obtained from the naked melanosome model in vitro. Finally, we determined the effects of melanosomal fractions exposed to HQ or D-Arb on hydroxyl radical generation in the Fenton reaction utilizing an electron spin resonance assay. D-Arb-treated melanosomesexhibit a moderate hydroxyl radical-scavenging activity, whereas HQ-treated melanosomessignificantly generate more hydroxyl free radicals. This study suggests that D-Arb possesses a potent ability in skin lightening and antioxidation with less melanosome cytotoxicity.

Asymmetric stem-cell division ensures sustained keratinocyte hyperproliferation in psoriatic skin lesions.

Excessive expansion of the transit-amplifying (TA) cell compartment is a distinct morphological characteristic of psoriatic epidermal hyperplasia. In order to examine the activation of basal stem cells and how they replenish such an enlarged compartment of TA cells in psoriatic epidermis, we utilized a BrdU labeling method to monitor mitotic stem cells in a mouse model of psoriasiform dermatitis, which was induced by imiquimod. Our results showed that perpendicular and parallel cell division characteristics of dividing stem cells existed in the inflamed epidermis. When we analyzed template­DNA strand segregation in trypsin-dissociated human psoriatic keratinocytes using BrdU pulse-chase labeling, we found that the percentage of asymmetric segregation of BrdU was significantly increased in the cell pairs of psoriatic epidermal cells compared with normal epidermal cells. Furthermore, we also examined the effects of both interleukin (IL)-17A and IL-22 cytokines on the differentiation status of cultured human keratinocytes. The results indicated that both cytokines had synergistic effects on passage-one epidermal cell sheets derived from skin explants and also on cultured keratinocytes, were involved in the maintenance of the undifferentiated stem cell phenotype, and these results suggest an efficient mechanism for preventing the premature loss of basal stem-cell pools in the pro-inflammatory cytokine-enriched milieu of the psoriatic epidermis. Our findings suggest that inhibition of hyperactive stem cells represents a potential therapeutic target to combat recalcitrant epidermal hyperplasia in psoriasis.

Premature graying as a consequence of compromised antioxidant activity in hair bulb melanocytes and their precursors.

Intricate coordinated mechanisms that govern the synchrony of hair growth and melanin synthesis remain largely unclear. These two events can be uncoupled in prematurely gray hair, probably due to oxidative insults that lead to the death of oxidative stress-sensitive melanocytes. In this study, we examined the gene expression profiles of middle (bulge) and lower (hair bulb) segments that had been micro-dissected from unpigmented and from normally pigmented hair follicles from the same donors using quantitative real-time RT-PCR (qPCR) arrays. We found a significant down-regulation of melanogenesis-related genes (TYR, TYRP1, MITF, PAX3, POMC) in unpigmented hair bulbs and of marker genes typical for melanocyte precursor cells (PAX3, SOX10, DCT) in unpigmented mid-segments compared with their pigmented analogues. qPCR, western blotting and spin trapping assays revealed that catalase protein expression and hydroxyl radical scavenging activities are strongly repressed in unpigmented hair follicles. These data provide the first clear evidence that compromised antioxidant activity in gray hair follicles simultaneously affects mature hair bulb melanocytes and their immature precursor cells in the bulge region.

Insufficient expression of the melanocortin-1 receptor by human dermal fibroblasts contributes to excess collagen synthesis in keloid scars.

Activation of the α-melanocyte-stimulating hormone (αMSH)/melanocortin-1 receptor (MC1R) signalling pathway exerts antagonistic actions on cutaneous inflammatory and fibrogenic responses in addition to promoting pigment production. Herein, the expression of MC1R by keloid-derived fibroblasts and keloid scar tissue was investigated using a range of techniques. MC1R mRNA expression levels in five different keloid fibroblast cell lines were significantly reduced to less than half compared with five normal fibroblast cell lines (P < 0.05). Immunohistological analysis of tissue samples indicated that MCR1 immunoreactivity in both epidermal and dermal compartments of five keloid tissue samples was dramatically decreased compared with normal skin (P < 0.05). Insufficient expression of MC1R on human dermal fibroblasts might abolish the αMSH-mediated suppression of collagen production and myofibroblast transformation elicited by the profibrotic cytokine-transforming growth factor-ß1. Restoration of reduced MC1R by dermal fibroblasts may lead to novel scar-reducing therapeutic approaches for treating this refractory fibrotic disease.

Detailed histological structure of human hair follicle bulge region at different ages: a visible niche for nesting adult stem cells.

In the bulge region of the hair follicle, a densely and concentrically packed cell mass is encircled by the arrector pili muscle (APM), which offers a specilized microenvironment (niche) for housing heterogeneous adult stem cells. However, the detailed histological architecture and the cellular composition of the bulge region warrants intensive study and may have implications for the regulation of hair follicle growth regulation. This study was designed to define the gene-expression profiles of putative stem cells and lineage-specific precursors in the mid-portions of plucked hair follicles prepared according to the presence of detectable autofluorescence. The structure was also characterized by using a consecutive sectioning technique. The bulge region of the hair follicle with autofluorescence was precisely excised by employing a micro-dissection procedure. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was performed to identify the gene expression profiles specific for epithelial, melanocyte and stromal stem cells in the bulge region of the hair follicle visualized by autofluorescence. The morphology and its age-dependent changes of bulge region of the hair follicles with autofluorescence segment were also examined in 9 scalp skin specimens collected from patients aged 30 weeks to 75 years, by serial sectioning and immuno-staining. Gene expression profile analysis revealed that there were cells with mRNA transcripts of Dct(Hi)Tyrase(Lo)-Tyrp1(Lo)MC1R(Lo)MITF(Lo)/K15(Hi)/NPNT(Hi) in the bulge region of the hair follicle with autofluorescence segments, which differed from the patterns in hair bulbs. Small cell-protrusions that sprouted from the outer root sheath (ORS) were clearly observed at the APM inserting level in serial sections of hair follicles by immunohistological staining, which were characteristically replete with K15+/K19+expressing cells. Likewise, the muscle bundles of APM positive for smooth muscle actin intimately encircled these cell-protrusions, and the occurrence frequency of the cell-protrusions was increased in fetal scalp skin compared with adult scalp skin. This study provided the evidence that the cell-protrusions occurring at the ORS relative to the APM insertion are more likely to be characteristic of the visible niches that are filled with abundant stem cells. The occurrence frequency of these cell-protrusions was significantly increased in fetal scalp skin samples (128%) as compared with the scalp skins of younger (49.4%) and older (25.4%) adults (P<0.01), but difference in the frequency between the two adult groups were not significant. These results indicated that these cell-protrusions function as a niche house for the myriad stem cells and/or precursors to meet the needs of the development of hair follicles in an embryo. The micro-dissection used in this study was simple and reliable in excising the bulge region of the hair follicle with autofluorescence segments dependent on their autofluorescence is of value for the study of stem cell culture.

Maintenance of immune hyporesponsiveness to melanosomal proteins by DHICA-mediated antioxidation: Possible implications for autoimmune vitiligo.

Melanocyte destruction in the skin of vitiligo patients has been considered to be a consequence of an autoimmune response against melanosomal proteins. However, little is known about the molecular mechanisms by which the immune system recognizes these sequestered intracellular self-proteins, which are confined in specialized organelles termed melanosomes, and is provoked into an autoimmune response to melanocytes. Here, we utilize a sucrose density-gradient ultracentrifugation protocol to enrich melanosomal components from dopachrome tautomerase (Dct)-mutant or wild-type melanocytes exposed to a pulse of hydrogen peroxide at a noncytotoxic concentration to evaluate their immunogenicity in mice challenged with the corresponding melanosomal proteins. The results demonstrate that enhanced humoral and cellular immune responses to a challenge with late-stage melanosomal proteins, especially with those derived from Dct-mutant melanocytes, are found in the immunized mice. To elucidate whether a reduced 5,6-dihydroxyindole-2-carboxylic acid (DHICA) content in melanin might cause a loss in antioxidative protection to the proteins, we incubated these melanosomal proteins in vitro with synthetic 5,6-dihydroindole (DHI)-melanin or DHI/DHICA (1:1)-melanin and then used them to immunize mice. T cell proliferation and IgG antibody responsiveness to the challenges were significantly induced by melanosomal proteins treated with DHI-melanin, but not by those treated with DHI/DHICA (1:1)-melanin. Moreover, we observed that melanosomal proteins derived from Dct-mutant melanocytes are subject to oxidative modifications that alter their antigenic configurations to attain an enhanced immunogenicity compared with those derived from wild-type melanocytes. From these results, we conclude that DHICA-mediated antioxidation plays a critical role in the maintenance of immune hyporesponsiveness to melanosomal proteins.

Photodynamic therapy as consolidation treatment for primary cutaneous adenoid cystic carcinoma: a case report.

OBJECTIVE: The purpose of this case report was to evaluate the efficacy of photodynamic therapy (PDT) for a patient with primary cutaneous adenoid cystic carcinoma (PCACC). MATERIALS AND METHODS: A 53-year-old female patient presented with a lesion at the pre-auricular area. After performing a local resection along a margin of 0.5 cm beyond the surrounding tissue, PCACC was clearly revealed based on the histological features and the exclusion of differentiation of other metastasis in the skin. The patient was then treated repetitively with 5-aminolevulinic acid (ALA)-PDT. After the final PDT treatment, the control pathological biopsy at the same location demonstrated no tumor cell in the specimen. RESULTS: The 40-month follow-up diagnosis showed no evidence of recurrence or metastasis observed on the treated area. CONCLUSION: ALA-PDT was a safe and effective therapy for obtaining good cosmetic results and reducing recurrence in this case report.

Regulation of DHICA-mediated antioxidation by dopachrome tautomerase: implication for skin photoprotection against UVA radiation.

Dopachrome tautomerase (Dct) is a critical enzyme in the melanogenesis pathway that isomerizes the intermediate dopachrome to 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and influences the proportion of DHICA monomer incorporated into the 5,6-dihydroxyindole (DHI) polymer in eumelanin. To investigate whether Dct inactivation affects skin photoprotection against ultraviolet radiation, we examined levels of reactive oxygen species (ROS), sunburn cell formation, epidermal cell apoptosis, and melanin composition in skins of Dct(-/-) knockout mice compared with skins of wild-type C57BL/6 mice under UVA-induced oxidative stress. The results demonstrate that Dct inactivation elevates the level of ROS, increases the numbers of sunburn cells and apoptotic cells, and decreases the amount of eumelanin in the epidermis upon exposure to chronic UVA radiation. Moreover, we determined the effects of DHICA-melanin, DHI-melanin, and a mixture of both on hydroxyl radical generation in the Fenton reaction utilizing an electron spin resonance assay. DHICA-melanin exhibits a potent hydroxyl radical-scavenging activity, whereas DHI-melanin does not. Thus, this study suggests that DHICA monomers are required to incorporate into the DHI polymer backbone of eumelanin, which highlights the important role of Dct in the regulation of DHICA-mediated antioxidation.

[Effects of mutation in dopachrome tautomerase on melanosome maturation and anti-oxidative potential in cultured melanocytes].

OBJECTIVE: To investigate whether the mutation in dopachrome tautomerase (Dct) affects melanosome maturation and anti-oxidative potential in cultured melanocytes (MCs). METHODS: Slaty and melan-a MCs were derived from the skins of neonatal Dct(Slt) and C57 BL/6J mice respectively. Their detailed melanosome structures were examined with a transmission electron microscopy (TEM) and their eumelanin granules characterized by Fontana-Masson staining. Furthermore, the tyrosinase activity and three melanogenic proteins, i. e., tyrosinase, tyrosinase-related protein 1 and Dct, were also measured with a spectrophotometry method or Western blot assay. The level of intracellular reactive oxygen species (ROS) was monitored by 2,7-dichlorofluorescin diacetate (DCF-DA) labeling. RESULTS: Mature stage IV melanosomes markedly decreased in slaty MCs under TEM. The brownish granules stained with Fontana-Masson silver method were far less in slaty MCs than in melan-a MCs. The cell pellet of slaty MCs was white in color, but the similarities between slaty and melan-a were found in tyrosinase activity and its protein expression. The relative intensity of DCF fluorescence was 8.9 +/- 0.7 for slaty melanocytes versus 8.9 +/- 2.5 for melan-a melanocytes prior to UVA irradiation, but an abrupt ROS production was merely observed in slaty MCs (18.0 +/- 0.3) other than in melan-a MCs (13.6 +/- 0.3) after UVA exposure. There was statistical difference between these two cell lines in ROS level upon UVA irradiation (P = 0.024). CONCLUSION: The mutation in Dct causes hypo-pigmented phenotype in cultured slaty MCs, inhibits melanosome maturation and decreases anti-oxidative capacity especially in the presence of UVA-induced oxidative stress.

[Effects of elevating temperature on photodynamic reaction in laryngeal squamous carcinoma cells induced by delta-aminolevulinic acid].

OBJECTIVE: To investigate effect of temperature on delta-aminolevulinic acid (ALA) induced photodynamic reaction in laryngeal squamous carcinoma cells. METHODS: Human laryngeal squamous carcinoma cells of the line Hep-2 cells were co-cultured with 2 mmol/L ALA (Group A) or without ALA (Group B) at the culturing temperature 19 - 46 degrees C. Three hours later cellular protoporphyrin IX (PpIX) level was determined by high performance liquid chromatography with fluorescent detection. Laser scanning confocal microscopy was used to observe the fluorescent strength in the Hep-2 cells. The ratio of cell death (including necrosis and apoptosis) was detected with flow cytometer before and after photodynamic reaction. RESULTS: In Group A the PpIX level at the temperature of 19 degrees C was (0.25 +/- 0.06) microg/L, and raised to (1.07 +/- 0.11) microg/L at 46 degrees C. There was no cellular PpIX detected in Group B at any temperature. Before laser radiation the cell death ratios of both groups were the same at the temperature 19 - 37 degrees C, and at the temperature 37 - 46 degrees C. After laser radiation the cell death ratio of Group A raised from 31.11% to 98.92% as the temperature went up steadily, but the results of Group B showed the same curve as before laser radiation. At any same temperatures the cell death ratios of Group A were all significantly higher than those of Group B (all P < 0.05), and as the temperature was elevated the difference between the 2 groups raised from 28.99% to 59.26%. CONCLUSION: Moderate higher temperature enhances the PpIX production and photodynamic reaction in human laryngeal squamous carcinoma induced by ALA in vitro.

Effects of hydroquinone and its glucoside derivatives on melanogenesis and antioxidation: Biosafety as skin whitening agents.

BACKGROUND AND OBJECTIVE: The biosafety of hydroquinone and its derivatives as skin whitening agent remains controversial. Here, we investigated the effects of hydroquinone, arbutin, and deoxyarbutin (d-arb) on melanogenesis and antioxidation using cultured melan-a melanocytes in the presence or absence of ultraviolet A (UVA)-induced oxidative stress and determined whether d-arb enables to be an alterative to hydroquinone and arbutin for skin whitening use. METHODS: d-arb was synthesized in this study by removing all hydroxyl groups from the glucose side-chain of arbutin. Tyrosinase activity was measured by (14)C-tyrosine incorporation, the intracellular reactive oxygen species (ROS) level was monitored by H(2)DCFDA fluorescence labeling, and the cell viability was determined by MTT assay in murine melan-a melanocytes treated with hydroquinone, arbutin and deoxyarbutin in the presence or absence of UVA-induced oxidative stress. RESULTS: The cytotoxicity of hydroquinone and arbutin except for d-arb was increased while the cells exposed to a nontoxic dose (3J/cm(2)) of UVA irradiation. Suppressed ROS generation was noted by the treatment of d-arb to compare with arbutin and hydroquinone. All three compounds had a similar inhibition on tyrosinase activity in dose-dependent manners with two- to three-fold decreases over the untreated control. There was no change in expression of tyrosinase protein in cells treated with arbutin or hydroquinone, but a decreased protein expression of tyrosinase was seen in deoxyarbutin-treated cells. CONCLUSIONS: Deoxyarbutin exerts potent tyrosinase inhibition, lessened cytotoxicity, and certain antioxidation potential, may serve as an effective and safe alternative to hydroquinone for use in skin whitening.

Treatment of skin cancer and pre-cancer using topical ALA-PDT--a single hospital experience.

Our hospital (Shanghai Skin Diseases & STD Hospital) started to study 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) in 1996. So far, we have treated 76 cases of skin cancer and pre-cancer using topical ALA-PDT. They included squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), mammary and extramammary Paget disease, actinic keratosis (AK) and erythroplasia of Queyrat. In this overview article, we would like to present several representative cases and discuss our experience.

Influence of CaNa2 EDTA on topical 5-aminolaevulinic acid photodynamic therapy.

BACKGROUND: We assessed whether the CaNa2 EDTA could improve the accumulation of protoporphyrin IX (PpIX) and photosensitisation in HEp-2 cells as well as the depth of treatment of skin cancers on the topical 5-Aminolaevulinic acid (5-ALA) PDT. METHODS: HEp-2 cells were incubated with 5-ALA (0-1 mmol/L) and CaNa2EDTA (0-1 mmol/L) for 4 hours, intracellular protoporphyrin IX content was quantified by extraction, and cell viability was assessed by use of the methyl-tetrazolium (MTT) assay four hours after exposure to light. In comparison with the pictures before and after treatment, depth of treatment could be determined using a Acuson Sequioa 512 phase-array system in paired experiments. RESULTS: PpIX accumulation increased with increasing extracellular concentrations of ALA (0-1 mmol/L). Adding 1 mmol/L of CaNa2EDTA increased 30% PpIX accumulation over the same period of incubation in the concentration of 1 mmol/L ALA. Significant difference was observed between the 5-ALA alone group and 5-ALA combined CaNa2 EDTA group in the PpIX accumulation (P < 0.01). Cell viability after exposure to light decreased with adding CaNa2 EDTA, a statistical difference in a same fluence above 1.2 J/cm2 between two groups was demonstrated (P < 0.05, P < 0.01 respectively). Depth of treatment of skin cancers were increased in CaNa2 EDTA-treated group. CONCLUSION: CaNa2 EDTA could improve the PpIX accumulation and photosensitisation in HEp-2 cells. Clinically, CaNa2 EDTA could increase the depth of treatment in the cutaneous cancers.

Evaluation of photodynamic therapy of skin cancers with partial differential alpha-aminolevulinic acid.

OBJECTIVE: To use partial differential -aminolevulinic acid induced photodynamic therapy (ALA-PDT) increasingly in treating skin cancers and other diseases in many countries and to explore the efficacy of ALA-PDT for skin cancers in China. METHODS: Eighty-eight patients, including 34 cases of basal cell carcinoma (BCC), 32 cases of squamous cell carcinoma (SCC), two cases of basal-squamous cell carcinoma (BSCC), one case of verrucuous carcinoma, nine cases of Bowen disease, two cases Paget disease of the nipple and eight cases of extramammary Paget disease, were treated by the partial differential alpha-aminolevulinic acid induced photodynamic therapy first in China from 1997 to 2000. RESULTS: All BCC, including 11 cases of superficial lesions and 29 solid lesions, achieved complete reaction (CR) by 1-4 times of the ALA-PDT. Except one patient with adenoid SCC (grade III), all SCC (grade I and grade II) patients achieved complete remission by 3-6 times of ALA-PDT. All Bowen diseases achieved complete reaction by 1-4 times. Although for Paget diseases it could not cure the disease simply by ALA-PDT, it could control the symptoms. The recurrence rates were 11% (4/34) for BCC, and 22% (7/32) for SCC by following up 1-3 years after the therapy. The continuous therapy is still effective. CONCLUSIONS: ALA-PDT is an effective, non-traumatic treatment for patients with BCC, SCC, Bowen and Paget diseases. It is especially suitable for older and weaker patients or those who are not tolerable to other therapies. It also has a unique advantage for tumors in specific anatomical areas. It is a new alternative modality for skin cancer therapies.