Primary Clinical Evaluation of Photodynamic Therapy With Oral Leukoplakia in Chinese Patients

Differences in the response of normal oral mucosa, oral leukoplakia, oral squamous cell carcinoma-derived mesenchymal stem cells, and epithelial cells to photodynamic therapy

OBJECTIVE

The objective of this study is to investigate the variances in transcriptome gene expression of normal oral mucosa-derived mesenchymal stem cell (OM-MSC), oral leukoplakia-derived MSC (OLK-MSC) and oral squamous cell carcinoma-derived MSC(OSCC-MSC). as Additionally, the study aims to compare the in vitro proliferation, migration, invasion ability, and response to photodynamic therapy (PDT) of these three MSC, HOK, DOK, leuk1, and Cal27 cell lines.

METHODS

HOK, DOK, leuk1, Cal27 cells were cultured in vitro. 3 MSC cells were obtained from OM, OLK, OSCC tissue (n = 3) and identified through flow cytometry. They were also cultured in vitro for osteogenic and lipogenic-induced differentiation. Based on the Illumina HiSeq high-throughput sequencing platform, OM-MSC, OLK-MSC, OSCC-MSC (n = 3) were subjected to transcriptome sequencing, functional annotation, and enrichment analysis of differentially expressed genes and related genes. CCK8 assay, wound healing assay, and transwell assay were performed to compare the proliferation, migration, and invasion of the seven types of cells. The 7 cells were incubated with 0, 0.125 mM, 0.25 mM, 0.5 mM, 1 mM, and 2 mM of the photosensitizer (5-aminolevulinic acid, 5-ALA) in vitro. Subsequently, they were irradiated with a 150 mM, 635 nm laser for 1 min, and the cell activity was detected using the CCK8 assay after 24 h. The mitochondrial changes in the 7 cells before and after the treatment of PDT were detected using the JC-10 probe, and the changes in ATP content were measured before and after the PDT treatment.

RESULTS

OM-MSC, OLK-MSC, and OSCC-MSC expressed positive MSC surface markers. After osteogenic and lipogenic-induced differentiation culture, stained calcium nodules and lipid droplets were visible, meeting the identification criteria of MSC. Pathway enrichment analysis revealed that the differentially expressed genes (DEGs) of OSCC-MSC compared to OLK-MSC were primarily associated with the PI3K-Akt signaling pathway and tumor-related pathways. OSCC-MSC exhibited stronger migratory and invasive abilities compared to Cal27. The IC50 values required for OM, OLK, and OSCC-derived MSC were lower than those required for epithelial cells treated with PDT, which were 1.396 mM, 0.9063 mM, and 2.924 mM, respectively. Cell membrane and mitochondrial disruption were observed in seven types of cells after 24 h of PDT treatment. However, HOK, DOK, leuk1, and Cal27 cells had an ATP content increased.

CONCLUSIONS

OLK, OSCC epithelial cells require higher concentrations of 5-ALA for PDT treatment than MSC of the same tissue origin. The concentration of 5-ALA required increases with increasing cell malignancy. Differences in the response of epithelial cells and MSC to PDT treatment may have varying impacts on OLK recurrence and malignancy.

CLINICAL EFFICACY OF PHOTODYNAMIC THERAPY IN MANAGEMENT OF ORAL POTENTIALLY MALIGNANT DISORDERS: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVES

Despite phototherapy (in the form of photodynamic therapy (PDT)-mediated oxidative stress) being utilized in the management of oral potentially malignant disorders (OPMDs), the evidence of certainty remains unclear. Hence, this systematic review and meta-analysis (PROSPERO # CRD42021218748) is aimed to evaluate the clinical efficacy of PDT-induced oxidative stress in OPMDs METHODS: PubMed, Embase, Web of Science, Scopus, and Cochrane Library databases were searched without restriction of language or year of publication. In addition, gray literature was searched and a manual search was performed. Two independent reviewers screened all the studies, assessing data extraction, risk of bias and certainty of evidence. A narrative synthesis was carried out. For the meta-analysis, random effects were considered to determine the prevalence of a total and a partial remission (PR) of oral potentially malignant disorders (OPMDs). The certainty of evidence was explored using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-three studies were included in the qualitative and quantitative syntheses. A total of 880 patients were included (564 males; 218 females) with an age range between 24 and 89-years-old. The results showed the prevalence of the total and partial remissions respectively for the following OPMLs: actinic cheilitis (AC): 69.9% and 2.4%; oral leukoplakia (OL): 44% and 36.9%; oral verrucous hyperplasia (OVH): 98.5%; oral erythroleukoplakia (OEL): 92.1% and 7.9%. The prevalence of no remission of OL was 18.8%.

CONCLUSIONS

PDT demonstrated significant results in clinical remission of OPMDs and most of the eligible studies have shown a total or a partial remission of the included lesions, but at a low or a very low certainty of evidence. Hence, further clinical studies with robust methodology are warranted to offer further validated data. Also, further evidence is required to understand further the mechanism of PDT-induced oxidative stress.

Clinical efficacy of photodynamic therapy of oral potentially malignant disorder

OBJECTIVE

To investigate the clinical efficacy of aminovalerate hydrochloride photodynamic therapy (PDT) for oral potentially malignant disorder (OPMD),oral leukoplakia (OLK), along with identifying the influencing factors.Additionally, the study aims to detect the rates of recurrence and malignancy after PDT.

METHOD

60 patients with OPMD who received PDT at our hospital from 2006 to 2021 were included in this study. Relevant patient medical data were collected and analyzed using SAS 9.4 software.The Mann-Whitney U test was used to retrospectively analyze the factors influencing clinical efficacy, as well as recurrence rate and malignant transformation rate (MTR) after treatment.

RESULT

Among the 60 OPMD patients receiving PDT, complete remission in 13 (21.67 %), partial remission in 39 (65.00 %), and no remission in eight (13.33 %), resulting in an overall effective rate of 86.67 %.Fifteen patients experienced relapse, leading to a recurrence rate of 25.00 %. Among these relapses,11 patients occurred within one year after treatment, corresponding to an 18.33 % recurrence rate during that period. Moreover, nine patients developed malignant transformation (MT), resulting in an MTR of 15.00 %. Out of these patients, six individuals developed MT within one year after treatment, resulting in a one-year MTR of 10.00 %.

CONCLUSION

The study findings indicate that PDT shows promising clinical efficacy in the treatment of OPMD, with relatively limited and tolerable postoperative adverse reactions. However, there remains a certain rate of recurrence and malignancy after treatment. Therefore, close attention should be paid to postoperative monitoring, regular follow-up, and further expansion of the sample size to observe its long-term efficacy.

Photodynamic Therapy for Eye, Ear, Laryngeal Area, and Nasal and Oral Cavity Diseases: A Review

Photodynamic therapy (PDT) has emerged as a promising modality for the treatment of various diseases. This non-invasive approach utilizes photosensitizing agents and light to selectively target and destroy abnormal cells, providing a valuable alternative to traditional treatments. Research studies have explored the application of PDT in different areas of the head. Research is focusing on a growing number of new developments and treatments for cancer. One of these methods is PDT. Photodynamic therapy is now a revolutionary, progressive method of cancer therapy. A very important feature of PDT is that cells cannot become immune to singlet oxygen. With this therapy, patients can avoid lengthy and costly surgeries. PDT therapy is referred to as a safe and highly selective therapy. These studies collectively highlight the potential of PDT as a valuable therapeutic option in treating the head area. As research in this field progresses, PDT may become increasingly integrated into the clinical management of these conditions, offering a balance between effectiveness and minimal invasiveness.

Clinical evaluation of photodynamic therapy for oral leukoplakia: a retrospective study of 50 patients

BACKGROUND

Topical photodynamic therapy (PDT) has demonstrated encouraging results in the treatment of oral leukoplakia (OLK). However, data on the clinical efficacy of PDT in Chinese patients with OLK are still limited.

METHODS

Fifty patients diagnosed with OLK were enrolled, including patients with various dysplastic tissues. All patients received topical PDT with 5-aminolevulinic acid (5-ALA) as a photosensitizer. Clinical efficacy was evaluated 4 weeks after treatment. Follow-up was performed every 3 months during the first year and every 6 months during the second year.

RESULTS

The overall response rate was 68% (34/50): 12% (n = 6) complete and 56% (n = 28) partial responses. Aneuploidy was reduced in the patients with dysplastic lesions. Oral pain and local ulcers developed in 52% of the patients (n = 26). Patients with a long history of OLK including hyperplasia and dysplastic lesions, as well as those with non-homogenous lesions, were more likely to develop pain and ulcer. During follow-up, the recurrence rate of hyperplasia and dysplastic lesions was 32% (n = 16) and the malignant transformation rate of dysplastic lesions was 4% (n = 2). Lesions on the buccal mucosa were associated with recurrence (P = 0.044; OR: 0.108, 95% CI: 0.013-0.915).

CONCLUSION

Topical 5-ALA-mediated PDT is an effective treatment for OLK, particularly for homogenous leukoplakia, with few side effects. The buccal mucosa may be a protective factor that can reduce recurrence.

Evaluating photodynamic therapy for oral precancerous lesions: Highlighting outcome measure of malignant transformation

The main outcome measure assessed in previous studies on photodynamic therapy (PDT) for oral precancerous lesions (OPL) is clinical response based on the alteration in lesion size after treatment. However, the primary and secondary outcome measures of the interventions for OPL should be malignant transformation and recurrence. Thus, the objective of this short communication is to summarize the evidence on PDT in preventing the recurrence and malignant transformation of OPL. There were 16 eligible studies which addressed the issue of OPL patients who received PDT with recurrence outcome, and the pooled recurrence rate (95% confidence interval) was analyzed to be 20.1% (16.2-24.6%). Notably, only 1 study reported that 7.5% of malignant transformation rate for OPL received PDT. These should be interpreted with caution due to low-level evidence, such as differences in study design, clinical and pathological features of patients enrolled, limited sample size, short follow-up time. Given few evaluated the effect of PDT on malignant transformation, we highlight that this primary outcome measure of OPL needs to be investigated in further well-designed longitudinal studies with adequate follow-up periods.

Recent advances in fluorescence imaging-guided photothermal therapy and photodynamic therapy for cancer: From near-infrared-I to near-infrared-II

Phototherapy (including photothermal therapy, PTT; and photodynamic therapy, PDT) has been widely used for cancer treatment, but conventional PTT/PDT show limited therapeutic effects due to the lack of disease recognition ability. The integration of fluorescence imaging with PTT/PDT can reveal tumor locations in a real-time manner, holding great potential in early diagnosis and precision treatment of cancers. However, the traditional fluorescence imaging in the visible and near-infrared-I regions (VIS/NIR-I, 400-900 nm) might be interfered by the scattering and autofluorescence from tissues, leading to a low imaging resolution and high false positive rate. The deeper near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging can address these interferences. Combining NIR-II fluorescence imaging with PTT/PDT can significantly improve the accuracy of tumor theranostics and minimize damages to normal tissues. This review summarized recent advances in tumor PTT/PDT and NIR-II fluorophores, especially discussed achievements, challenges and prospects around NIR-II fluorescence imaging-guided PTT/PDT for cancers.

In vitro comparative effects of laser photodynamic therapy with methylene blue or aminolevulinic acid on oral squamous cell carcinoma cell line

Background

This study aimed to compare the effects of laser photodynamic therapy (PDT) with methylene blue (MB) or aminolevulinic acid (ALA) on the oral squamous cell carcinoma (OSCC) cell line.

Materials and Methods

In this in vitro experimental study, the C152 (KB) OSCC cell line was cultured in a culture medium containing 10% fetal bovine serum. The cells were exposed to 0.1, 0.2, 0.5, 1, 2, 5, and 10 mM concentrations of MB and ALA alone and combined with diode laser irradiation with 660 nm wavelength, 40 mW power, and 10 J/cm2 energy density in continuous-wave mode perpendicular to the surface. Cell viability was assessed using the methyl thiazolyl tetrazolium assay and compared among the groups by the Kruskal-Wallis test.

Results

The results showed that the reduction in cell viability in the MB + laser and ALA + laser groups was greater than that in the MB and ALA groups without laser (P < 0.001). Significant differences were noted in cell viability in the presence of some different concentrations of MB and ALA (P < 0.05), such that by an increase in their concentration, cell viability decreased. Cell viability in the MB + laser group was significantly lower than that in the ALA + laser group in some photosensitizer concentrations (P < 0.05).

Conclusion

Within the limitations of this in vitro study, the results showed that laser PDT with MB (high concentrations) was more effective than laser PDT with ALA against the OSCC cell line.

Photodynamic therapy (PDT) for oral leukoplakia: a systematic review and meta-analysis of single-arm studies examining efficacy and subgroup analyses

OBJECTIVE

This study aims to evaluate the efficacy of photodynamic therapy (PDT) in the treatment of oral leukoplakia and explore the subgroup factors that may influence its effectiveness.

METHODS

A systematic search was conducted in PubMed, Embase, the Cochrane Library, and Web of Science databases to identify relevant studies. Meta-analysis was performed using Stata15.0 software. Cochran's Q test and I2 statistics were used to evaluate heterogeneity, egger's test was used to evaluate publication bias.

RESULTS

The analysis of 17 studies included in this study suggests that PDT may be effective in achieving complete response (CR) [ES = 0.50, 95%CI: (0.33,0.66)], partial response (PR) [ES = 0.42, 95%CI: (0.27,0.56)], no response (NR) [ES = 0.19, 95%CI: (0.11,0.27)]in patients with oral leukoplakia. The recurrence rate was also evaluated [ES = 0.13, 95%CI: (0.08,0.18)]. Subgroup analysis showed that various factors such as light source, wavelength, medium, duration of application, clinical and pathological diagnosis classification influenced efficacy of PDT. The lesion areas of the leukoplakia after treatment were reduced by 1.97cm2 compared with those before treatment.

CONCLUSION

Our findings show that PDT is a viable treatment for oral leukoplakia. However, the effectiveness of the therapy may depend on several factors, as suggested by our subgroup analyses. (Registration no. CRD42023399848 in Prospero, 26/02/2023).

Functional drug-delivery hydrogels for oral and maxillofacial wound healing

The repair process for oral and maxillofacial injuries involves hemostasis, inflammation, proliferation, and remodeling. Injury repair involves a variety of cells, including platelets, immune cells, fibroblasts, and various cytokines. Rapid and adequate healing of oral and maxillofacial trauma is a major concern to patients. Functional drug-delivery hydrogels play an active role in promoting wound healing and have shown unique advantages in wound dressings. Functional hydrogels promote wound healing through their adhesive, anti-inflammatory, antioxidant, antibacterial, hemostatic, angiogenic, and re-epithelialization-promoting properties, effectively sealing wounds and reducing inflammation. In addition, functional hydrogels can respond to changes in temperature, light, magnetic fields, pH, and reactive oxygen species to release drugs, enabling precise treatment. Furthermore, hydrogels can deliver various cargos that promote healing, including nucleic acids, cytokines, small-molecule drugs, stem cells, exosomes, and nanomaterials. Therefore, functional drug-delivery hydrogels have a positive impact on the healing of oral and maxillofacial injuries. This review describes the oral mucosal structure and healing process and summarizes the currently available responsive hydrogels used to promote wound healing.

Developmental synergism in the management of oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are associated with an increased risk of occurrence of cancers of the oral cavity or lips. The unifying theme of OPMDs is their potential risk for cancer development. Therefore, the primary objective of the management should be to prevent carcinogenesis. Beyond diagnosis, current strategies for the management of OPMDs predominantly include non-surgical and surgical interventions and a "watch-and-see" approach, such as disease monitoring or surveillance, and preventive strategies. Though no optimal clinical treatment has gained universal approval for reducing or preventing malignant development of OPMDs. Therefore, an urgent need exits for improved treatment properties and effective predictive markers for OPMDs treatment. This review aims to outline recent synergism regarding to the management of OPMDs. Developing new technologies and improved application parameters to promote the treatment efficacy and a novel management prescription approach to OPMDs are proposed.

Reaching new lights: a review on photo-controlled nanomedicines and their in vivo evaluation

The selective and efficient delivery of bioactive molecules to sites of interest remains a formidable challenge in medicine. In recent years, it has been shown that stimuli-responsive drug delivery systems display several advantages over traditional drug administration such as an improved pharmacokinetic profile and the desirable ability to gain control over release. Light emerged as one of the most powerful stimuli due to its high biocompatibility, spatio-temporal control, and non-invasiveness. On the road to clinical translation, various chemical systems of high complexity have been reported with the aim to improve efficacy, safety, and versatility of drug delivery under complex biological conditions. For future research on the chemical design of such photo-controlled nanomedicines, it is essential to gain an understanding of their in vivo translation and efficiency. Here, we discuss photo-controlled nanomedicines that have been evaluated in vivo and provide an overview of the state-of-the-art that should guide future research design.

Effect of ALA-PDT on inhibition of oral precancerous cell growth and its related mechanisms

BACKROUND

Early treatment of oral precancerous lesions is considered as a key strategy for in oral carcinogenesis prevention. Increasing evidence has suggested that the transforming growth factor beta (TGF-β) signaling pathway is tightly involved in the process of oral-carcinogenesis. In this study, we investigated the inhibition effect and potential mechanism of 5-aminolaevulinic acid photodynamic therapy (ALA-PDT) in human oral precancerous cells via TGF-β pathway.

MATERIALS AND METHODS

Here, the dysplastic oral keratinocyte (DOK) cells were incubated with ALA concentration of 1 mM/mL for 4 h and then irradiated with a Helium-Neon (He-Ne) ion laser at 633 nm (200 mW/cm²). The control cells were cultured in Dulbecco's modified Eagle's medium (DMEM) medium. We analyzed the differentially expressed genes and correlated pathways in oral precancerous cells following ALA-PDT using Affymetrix microarrays. TGF-β pathway was analyzed by quantitative real-time polymerase chain reaction (RT-qPCR) and western blotting. Bioinformatics analysis was performed to evaluate the expression of TGF-β1 in human oral cancer samples and adjacent normal samples. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), flow cytometry, 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and wound healing assay were used to assess the effects of ALA-PDT plus TGF-β receptor inhibitor (LY2109761) in DOK cells.

RESULTS

The TGF-β signaling could exert in suppressive effects on DOK cells after ALA-PDT. The cell proliferation and migration rate of DOK cells was significantly reduced and apoptosis and ROS generation induced more effectively by ALA-PDT combined with LY2109761. Furthermore, cell cycle analysis revealed that the combined treatment resulted in G0/G1 phase arrest.

CONCLUSIONS

ALA-PDT suppresses the growth of oral precancerous cells by regulating the TGF-β signaling pathway, and its suppressive effect was enhanced using LY2109761. These results indicate that it could be a promising alternative treatment against oral precancerous lesions.

Nimotuzumab shows an additive effect to inhibit cell growth of ALA-PDT treated oral cancer cells

Oral squamous cell carcinoma (OSCC) is characterized by severe functional impairment and a poor prognosis. The epidermal growth factor receptor (EGFR) is highly expressed in OSCC and is a promising target for cancer therapy. In addition, aminolevulinic acid-induced photodynamic therapy (ALA-PDT) has produced robust clinical effects and showed some advantages over radiotherapy in oral cancer. Here, an EGFR inhibitor, nimotuzumab, was administered to 2 OSCC cell lines, CAL-27 and SCC-25, treated with ALA-PDT. Cell growth, apoptosis, and reactive oxygen species (ROS) generation were used to measure the antitumor activity of the combination therapy. The in vivo effect of nimotuzumab plus ALA-PDT was done using a mouse OSCC xenograft model (SCC-25). EGFR expression was further compared by Western blotting in different groups. We observed that nimotuzumab combined with ALA-PDT could enhance inhibition of OSCC cell growth in vitro and in vivo. We also observed an enhanced effect after combination on cell apoptosis in CAL-27 and SCC-25 cells. Furthermore, combined therapy significantly reduced the protein expression levels of EGFR in vitro. However, we observed that nimotuzumab plus ALA-PDT did not increase ROS generation substantially in OSCC cells compared to the ALA-PDT group alone. These observations indicate that nimotuzumab combined with ALA-PDT has valuable applications for OSCC treatment.

Management of oral leukoplakia by ablative fractional laser‐assisted photodynamic therapy: A 3‐year retrospective study of 48 patients

Objectives

This study aimed to review the results of oral leucoplakia (OL) using ablative fractional laser‐assisted photodynamic therapy (AFL‐PDT) and to further evaluate the risk factors for recurrence and malignant transformation.

Materials and Methods

Forty‐eight patients diagnosed with OL using histopathology were enrolled in this study. All patients received one session of AFL‐PDT. Therapeutic efficacy was evaluated 1 month posttreatment. Follow‐up was scheduled every 3 months in the first year and every 6 months thereafter.

Results

An overall positive response rate of 87.5% (42/48) was achieved, including 62.5% (30/48) complete responses and 25.0% (12/48) partial responses. During the 3‐year follow‐up period, the recurrence and malignant transformation rates were 37.5% (18/48) and 8.3% (4/48), respectively. Lesions on gingiva/palate seemed to be associated with recurrence (p < 0.001; odds ratio [OR]: 1.64, 95% confidence interval [CI]: 1.13–2.37). The severity of epithelial dysplasia (p = 0.02; OR: 2.93, 95% CI: 1.96–4.42) and recurrence (p = 0.016; OR: 3.14, 95% CI: 2.04–4.84) were associated with a predisposition to malignant transformation.

Conclusions

AFL‐PDT is an effective management of OL, but requires close follow‐up. OL lesions on the gingiva/palate are predisposed to recurrence. OLs that recur with moderate/severe epithelial dysplasia have a higher risk of transforming into oral squamous cell carcinoma.

Multifunctional photodynamic/photothermal nano-agents for the treatment of oral leukoplakia

Oral leukoplakia (OLK) has gained extensive attention because of the potential risk for malignant transformation. Photosensitizers (PSs) played an indispensable role in the photodynamic therapy (PDT) of OLK, but the poor light sensitivity greatly hampered its clinical application. Herein, a novel organic photosensitive ITIC-Th nanoparticles (ITIC-Th NPs) were developed for OLK photodynamic/photothermal therapy (PTT). ITIC-Th NPs present both high photothermal conversion efficiency (~ 38%) and suitable reactive oxygen species (ROS) generation ability under 660 nm laser irradiation, making them possess excellent PDT and PTT capability. In 4-nitroquinoline 1-oxide (4NQO)-induced oral precancerous animal models, ITIC-Th NPs effectively suppress the OLK's cancerization without apparent topical or systemic toxicity in vivo. This study offers a promising therapeutic strategy for PDT and PTT in OLK treatment, and this study is the first interdisciplinary research in the field of multimodal therapy for OLK.

The use of topical ALA-photodynamic therapy combined with induction chemotherapy for locally advanced oral squamous cell carcinoma

BACKGROUNDS

Platinum-based induction chemotherapy (ICT) confers benefits in suitable patients with locally advanced head and neck squamous cell carcinoma (HNSCC). Additionally, the application of a proper local approach can not only promote the survival quality and alleviate the suffering, but also improve the resectability in patients with advanced malignant tumor. 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a promising minimally invasive therapy and has shown good efficacy in the treatment of patients bearing precancerous lesions and oral squamous cell carcinoma (OSCC). The aim of the study was to evaluate the application of topical ALA-PDT synchronized with ICT in locally advanced OSCC.

PATIENTS AND METHODS

This study described the application of topical ALA-PDT combined with TPF (docetaxel, cisplatin, and 5-fluorouracil) ICT in eleven patients treated due to locally advanced in the oral cavity. Patients qualified for this type of local treatment had cancerous lesions located on the surface of the gum or oral mucosa. The efficacy was evaluated based on the clinical response and complications of the patients.

RESULTS

All patients were treated with four courses (bi-weekly) of ALA-PDT with three courses of TPF containing ICT. After treatment, the overall response rate was 90.9%. Then ten patients with surgery experienced radical surgery alone or combined with radiotherapy except a patient with serious heart condition. In the follow-up period of 26-43 months (median duration of 34.1 months), no local recurrence was observed in cases. Only one patient (9.1%) died of unrelated myocardial infarction.

CONCLUSION

Topical ALA-PDT proved to be a safe treatment in OSCC patients with locally advanced sites, which could be an appropriate addition to ICT. Despite the short observation period and small sample size, it seems justified to conduct prospective studies for the evaluation of the efficacy and safety of topical ALA-PDT synchronized with ICT followed by surgery.

Ablative fractional laser-assisted photodynamic therapy vs. ablative fractional laser for oral leukoplakia treatment: A randomized, controlled pilot study

BACKGROUND

Ablative fractional laser-assisted photodynamic therapy (AFL-PDT) is explored as an effective method in some premalignant diseases, whereas the effect of AFL-PDT on oral leukoplakia (OL), the best-known precursor of oral squamous cell carcinoma, remains undetermined.

METHODS

Forty-eight patients, histologically diagnosed with OL, were randomized (1:1) to receive either AFL-PDT or ablative fractional laser (AFL) treatment. All patients were followed up at 1, 3, 6 and 12 months postoperatively. The primary endpoints of efficacy and clinical recurrence and the secondary endpoint of side effects were assessed.

RESULTS

Forty-four patients completed the study. The 100% effective cure rate in the AFL-PDT group was higher than that in AFL group (80.9%, P<0.05) with 19.1% difference (95%CI: 0.7-40.0%). Compared to AFL group, recurrence observed at 6 and 12 months post-treatment tended to occur in fewer patients in the AFL-PDT group (P<0.05). No severe adverse events or systemic side effects were observed in either group.

CONCLUSIONS

AFL-PDT may effectively reduce recurrence of OL with high clinical efficacy and good tolerability, suggesting it may be a promising treatment for OL.

Co-delivery of chitosan nanoparticles of 5-aminolevulinic acid and shGBAS for improving photodynamic therapy efficacy in oral squamous cell carcinomas

BACKGROUND

The improvement of gene therapy provides hope for the treatment of cancer. However, malignant tumor is a multifactorial disease, which remains difficult to be cured with a single therapy. Our previous study reported that mitochondrial genes glioblastoma-amplified sequence (GBAS) plays a role in the development and treatment of oral squamous cell carcinoma (OSCC). The current study focused on building a mitochondrial-targeting drug co-delivery system for combined photodynamic therapy (PDT) and gene therapy.

METHODS

5-aminolevulinic acid (ALA) photosensitizer loaded chitosan (CS) nanoparticles were prepared using ionic crosslinking method, and further synthesized with the GBAS gene plasmid DNA (shGBAS) by electrostatic attraction. We detected the effects of PDT using the co-delivery system (CS-ALA-shGBAS) on cell proliferation and mitochondrial injury by MTT and reactive oxygen species (ROS) assays, respectively. Additionally, a oral cancer Xenograft model of nude mice was built to test its inhibitive effect on the cancerous growth in vivo.

RESULTS

A novel nanocomposite, CS-ALA-shGBAS, was found to be spherical structures and had good dispersion, stability and hypotoxicity. Gel retardation assay showed that CS-ALA nanoparticle could synthesize shGBAS at and above Nanoparticle/Plasmid ratios of 1/2. Excitingly, the co-delivery system was suitable for transfected cells and displayed a superior mitochondrially targeted killing effect on OSCC in vitro and in vivo.

CONCLUSION

Our study provides evidence that the chitosan-based co-delivery system of ALA-induced protoporphyrin IX (PpIX) photosensitizer and GBAS gene may be a novel mode of combined therapy for OSCC.

Application of Texture and Fractal Dimension Analysis to Estimate Effectiveness of Oral Leukoplakia Treatment Using an Er:YAG Laser-A Prospective Study

BACKGROUND

Oral leukoplakia (OL) is a potential neoplasmic lesion. The aim of this study was to apply texture analysis (TA) and fractal dimension analysis (FDA) to estimate the effectiveness of OL treatment using an Er:YAG laser.

METHODS

Eighteen patients with 32 lesions were treated. Laser procedures were conducted using the LiteTouch™ Er:YAG Dental Laser. The diameter of the operational tip was 1.3 mm, the power was 50 mJ, the frequency was 50 Hz, and the wavelength was 2940 nm. TA was based on long and short-run emphasis inverse moments, difference entropy, inverse difference moment, and wavelet decomposition for two-dimensional photography. FDA was measured using the box-counting method.

RESULTS

Total response was achieved in 50% of lesions, partial response was observed in 47%, and 3% of lesions did not respond to treatment. Recurrence occurred in 34% of lesions. TA features indicated pathological images depicting leukoplakia and complete reconstruction of the correct mucosal image after laser ablation. The discrete wavelet transformation feature detects much larger structures than the properties derived from the run-length matrix and co-occurrence matrix.

CONCLUSIONS

The Er:YAG laser is an effective treatment method in cases of oral leukoplakia. Leukoplakia treatment by Er:YAG laser is an effective modality, as revealed by the oral mucosa microstructure. TA and FDA are promising methods to estimate the effectiveness of OL treatment.

Light Sources and Dosimetry Techniques for Photodynamic Therapy

Effective treatment delivery in photodynamic therapy (PDT) requires coordination of the light source, the photosensitizer, and the delivery device appropriate to the target tissue. Lasers, light-emitting diodes (LEDs), and lamps are the main types of light sources utilized for PDT applications. The choice of light source depends on the target location, photosensitizer used, and light dose to be delivered. Geometry of minimally accessible areas also plays a role in deciding light applicator type. Typically, optical fiber-based devices are used to deliver the treatment light close to the target. The optical properties of tissue also affect the distribution of the treatment light. Treatment light undergoes scattering and absorption in tissue. Most tissue will scatter light, but highly pigmented areas will absorb light, especially at short wavelengths. This review will summarize the basic physics of light sources, and describe methods for determining the dose delivered to the patient.

Differential in vitro sensitivity of oral precancerous and squamous cell carcinoma cell lines to 5-aminolevulinic acid-mediated photodynamic therapy

OBJECTIVES

The clinical effect of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) may be correlated with the degree of dysplasia of cancer tissues, but much is still unknown regarding the differences in its effectiveness, especially in oral cancer and precancerous lesions. The aim of this study is to compare the effects of ALA-PDT on a human oral precancerous cell line (DOK) and an oral squamous cell carcinoma cell line (CAL-27).

METHODS

First, we explored the dose- and time-dependent responses of DOK and CAL-27 cells to ALA-PDT. DOK and CAL-27 cells were incubated with various concentrations of ALA (from 0.25 to 2 mM), followed by PDT using laser irradiation at 635 nm. The resulting photocytotoxicity was assessed in both cell lines using MTT assays. Further, apoptosis was assessed using flow cytometry, reactive oxygen species (ROS) generation was evaluated with 2,7-dichlorofluorescein diacetate (DCFH2-DA), and the response to treatment was examined via RT-qPCR and Western blotting to measure the mRNA and protein expression levels of matrix metallopeptidase 2 (MMP-2) and MMP-9.

RESULTS

ALA-PDT inhibited the proliferation of DOK and CAL-27 cells in a dose- and time-dependent manner. Dose-effect and inhibition-time relationships were also found. The rates of DOK and CAL-27 cell apoptosis when the ALA dose was 1 mM were 30.66 ± 3.10% and 75.40 ± 1.29%, respectively (P < 0.01). Following PDT, compared with DOK cells, the ROS level in CAL-27 cells was significantly increased and was correlated with an increase in the ALA concentration. Mechanistically, both the mRNA and protein expression levels of MMP-2 and MMP-9 were found to be regulated in both cell types after ALA-PDT.

CONCLUSION

ALA-PDT effectively killed DOK and CAL-27 cells in a dose- and time-dependent manner in vitro. However, under the same conditions, the susceptibilities of these cell lines to ALA-PDT were different. Further studies are necessary to confirm whether this difference is present in clinical oral cancer and precancerous lesions.