Photobiomodulation is associated with a decrease in cell viability and migration in oral squamous cell carcinoma

Effects of photobiomodulation by low-power lasers and LEDs on the viability, migration, and invasion of breast cancer cells

Among the malignant tumors, breast cancer is the most commonly diagnosed worldwide, being the most prevalent in women. Photobiomodulation has been used for wound healing, swelling and pain reduction, and muscle repair. The application of photobiomodulation in cancer patients has been controversial. Therefore, a better understanding of radiation-induced effects involved in photobiomodulation on cancer cells is needed. Thus, this study aimed to investigate the effects of exposure to low-power lasers and LEDs on cell viability, migration, and invasion in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (23, 46, and 69 J/cm2, 0.77 W/cm2) and blue LED (160, 321, and 482 J/cm2, 5.35 W/cm2), alone or in combination. Cell viability was assessed using the WST-1 assay, cell migration was evaluated using the wound healing assay, and cell invasion was performed using the Matrigel transwell assay. Viability and migration were not altered in MCF-7 and MDA-MB-231 cultures after exposure to low-power red laser and blue LED. However, there was a decrease in cell invasion from the cultures of the two cell lines evaluated. The results suggest that photobiomodulation induced by low-power red laser and blue LED does not alter cell viability and migration but decreases cell invasion in human breast cancer cells.

Red Light and 5% Aminolaevulinic Acid (5%) Inhibit Proliferation and Migration of Dysplastic Oral Keratinocytes via ROS Production: An In Vitro Study

Undiagnosed and untreated oral precancerous lesions often progress into malignancies. Photodynamic therapy (PDT) might be a minimally invasive alternative to conventional treatments. 5-aminolevulinic acid (5-ALA) is one of the most commonly used photosensitizers in PDT, and it is effective on many cancer types. However, its hydrophilic characteristic limits cell membrane crossing. In the present study, the effect of a newly formulated gel containing 5% 5-ALA in combination with red light (ALAD-PDT) on a premalignant oral mucosa cell line was investigated. The dysplastic oral keratinocyte (DOK) cells were incubated with ALAD at different concentrations (0.1, 0.5, 1, and 2 mM) at two different times, 45 min or 4 h, and then irradiated for 7 min with a 630 nm LED (25 J/cm2). MTT assay, flow cytometry, wound healing assay, and quantitative PCR (qPCR) were performed. ALAD-PDT exerted inhibitory effects on the proliferation and migration of DOK cells by inducing ROS and necrosis. mRNA analysis showed modulation of apoptosis-related genes' expression (TP53, Bcl-2, survivin, caspase-3, and caspase-9). Furthermore, there was no difference between the shorter and longer incubation times. In conclusion, the inhibitory effect of the ALAD-PDT protocol observed in this study suggests that ALAD-PDT could be a promising novel treatment for oral precancerous lesions.

Photobiomodulation at molecular, cellular, and systemic levels

Since the reporting of Endre Mester's results, researchers have investigated the biological effects induced by non-ionizing radiation emitted from low-power lasers. Recently, owing to the use of light-emitting diodes (LEDs), the term photobiomodulation (PBM) has been used. However, the molecular, cellular, and systemic effects involved in PBM are still under investigation, and a better understanding of these effects could improve clinical safety and efficacy. Our aim was to review the molecular, cellular, and systemic effects involved in PBM to elucidate the levels of biological complexity. PBM occurs as a consequence of photon-photoacceptor interactions, which lead to the production of trigger molecules capable of inducing signaling, effector molecules, and transcription factors, which feature it at the molecular level. These molecules and factors are responsible for cellular effects, such as cell proliferation, migration, differentiation, and apoptosis, which feature PBM at the cellular level. Finally, molecular and cellular effects are responsible for systemic effects, such as modulation of the inflammatory process, promotion of tissue repair and wound healing, reduction of edema and pain, and improvement of muscle performance, which features PBM at the systemic level.

Photodynamic therapy with acai (Euterpe oleracea) and blue light in oral cells: A spectroscopic and cytotoxicity analysis

OBJECTIVE

To evaluate the potential of photodynamic therapy (PDT) with blue light-emitting diode (LED) 460 nm at 25, 50 and 100 J/cm² using three concentrations of acai extracts (100, 40, and 10 mg/ml), in the proliferation and viability of head and neck tumor lines (SCC9).

METHODS

Three groups of cells were analyzed for 3 days in an in vitro assay with MTT (3- (4,5-dimethylthiazol-2-yl) -2,5, -diphenyltetrazolium bromide) and crystal violet: cells in the absence of acai extract and PDT (control group); cells in the presence of acai extract and no light; and cells in the presence of acai extract and LED blue light (PDT groups).

RESULTS

When using acai as a PS combined with blue LED (460 nm, 0.7466 cm² , 1000 mW/cm² ) and irradiation at 25, 50, and 100 J/cm² , after 72 h, cell viability (p < 0.0001 vs. control, p = 0.0027 vs. 100 mg/ml açai group, p = 0.0039 vs. 40 mg/ml açai group, p = 0.0135 vs. 10 mg/ml açai group; One-Way ANOVA/Tukey) and proliferation (p < 0.05, One-Way ANOVA/Tukey) decreased.

CONCLUSION

The acai in question is a potential photosensitizer (PS), with blue light absorbance and efficacy against head and neck tumor lines (SCC9).

Effects of 5-ALA mediated photodynamic therapy in oral cancer stem cells

The aim of the present study was to investigate the effects of PDT using the photosensitizer 5-aminoulevulinic acid (5-ALA) in oral squamous cell carcinoma (OSCC) behavior, mainly regarding its role on the cancer stem cell (CSC) phenotypes and in maintenance of the stem cell properties. Two OSCC cell lines were used and divided in the groups: Control, 5-ALA, LED 6 J/cm² and PDT. MTT and Neutral red assays were used to access cellular viability, cell migration was evaluated by the wound healing assay. The stem cell phenotype was analyzed by flow cytometry to evaluate the CD44^high/ESA^high, CD44^high/ESA^low and CD44^low populations, by the clonogenic and tumor sphere formation assays as well as by RT-qPCR. The presence of Protoporphyrin IX in each CSC fraction was evaluated by flow cytometry. The OSCC cell lines showed a significant decrease in cell viability and migration after PDT. The percentage of CD44^high/ESA^high cells decreased after PDT, which was associated with an increase in the CD44^low cells and with a functional decrease in the colony and sphere formation capacity. CD44^high/ESA^high cells showed increased PpIX, which contributed for their greater sensitivity to PDT. INV gene increased significantly after PDT, indicating cellular differentiation. Altogether, our results demonstrate that 5-ALA mediated PDT decreases not only the fraction of oral CSC but also their functional capabilities, inducing their differentiation.

Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022

Disclaimer

This article is based on recommendations from the 12th WALT Congress, Nice, October 3-6, 2018, and a follow-up review of the existing data and the clinical observations of an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This article is informational in nature. As with all clinical materials, this paper should be used with a clear understanding that continued research and practice could result in new insights and recommendations. The review reflects the collective opinion and, as such, does not necessarily represent the opinion of any individual author. In no event shall the authors be liable for any decision made or action taken in reliance on the proposed protocols.

Objective

This position paper reviews the potential prophylactic and therapeutic effects of photobiomodulation (PBM) on side effects of cancer therapy, including chemotherapy (CT), radiation therapy (RT), and hematopoietic stem cell transplantation (HSCT).

Background

There is a considerable body of evidence supporting the efficacy of PBM for preventing oral mucositis (OM) in patients undergoing RT for head and neck cancer (HNC), CT, or HSCT. This could enhance patients’ quality of life, adherence to the prescribed cancer therapy, and treatment outcomes while reducing the cost of cancer care.

Methods

A literature review on PBM effectiveness and dosimetry considerations for managing certain complications of cancer therapy were conducted. A systematic review was conducted when numerous randomized controlled trials were available. Results were presented and discussed at an international consensus meeting at the World Association of photobiomoduLation Therapy (WALT) meeting in 2018 that included world expert oncologists, radiation oncologists, oral oncologists, and oral medicine professionals, physicists, engineers, and oncology researchers. The potential mechanism of action of PBM and evidence of PBM efficacy through reported outcomes for individual indications were assessed.

Results

There is a large body of evidence demonstrating the efficacy of PBM for preventing OM in certain cancer patient populations, as recently outlined by the Multinational Association for Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Building on these, the WALT group outlines evidence and prescribed PBM treatment parameters for prophylactic and therapeutic use in supportive care for radiodermatitis, dysphagia, xerostomia, dysgeusia, trismus, mucosal and bone necrosis, lymphedema, hand-foot syndrome, alopecia, oral and dermatologic chronic graft-versus-host disease, voice/speech alterations, peripheral neuropathy, and late fibrosis amongst cancer survivors.

Conclusions

There is robust evidence for using PBM to prevent and treat a broad range of complications in cancer care. Specific clinical practice guidelines or evidence-based expert consensus recommendations are provided. These recommendations are aimed at improving the clinical utilization of PBM therapy in supportive cancer care and promoting research in this field. It is anticipated these guidelines will be revised periodically.

Effect of low-level light therapy before radiotherapy in oral squamous cell carcinoma: An in vitro study

Radiation therapy for head and neck squamous cell carcinoma (HNSCC) is associated with several complications. Although photobiomodulation (PBM) has radioprotective effects in normal tissue, it could also enhance the growth of neoplastic cells. Thus, the present study aimed to investigate the cellular response of oral squamous cell carcinoma with pre-exposure to low-level phototherapy before radiotherapy. SCC9, Cal-27, A431, and HaCaT cell lines were subjected to low-level light therapy and radiotherapy. The cells were treated with a single energy density (300 J/cm²) of a light-emitting diode (660 nm) prior to ionizing radiation at different doses (0, 2, 4, and 6 Gy). After 24 h, wound scratch, proliferation, clonogenic cell survival, cell death, and reactive oxygen species (ROS) analyses were performed to evaluate cell response. The cell lines pre-exposed to PBM at the analyzed dosage were radiosensitive. The treatment significantly reduced cell proliferation and clonogenic cell survival. Migration and cell death assays also revealed positive results, with the treatment group showing lower rate of migration and higher cell death than did the control group. Moreover, PBM effectively increased the intracellular levels of ROS. PBM at 300 J/cm² is a promising radiosensitizing modality to reduce the radiation dose and avoid the intolerable side effects of radiotherapy for HNSCC, thus increasing the probability of successful treatment. However, further studies are needed to support and confirm the results.

Red Light Phototherapy Using Light-Emitting Diodes Inhibits Melanoma Proliferation and Alters Tumor Microenvironments

Background

Total annual cancer rates have decreased due to improved treatment and prevention. However, the incidence of melanoma is rising, and not all patients respond to immune and targeted approaches. Therefore, we sought to determine the efficacy of red light (RL) phototherapy in preclinical models of melanoma.

Methods

Melanoma cells (A375, B16F10, MNT-1) were irradiated with RL. Melanoma proliferation, apoptosis, oxidative stress, and p53 phosphorylation were measured in vitro. In C57BL/6 mice, phototherapy safety, B16F10 tumor growth, and immunocyte infiltration were assessed following RL.

Results

In vitro, 640 J/cm² RL decreased cellular proliferation without increasing apoptosis, while 1280 J/cm² increased apoptosis. RL increased intracellular reactive oxygen species generation and p53 phosphorylation. In animal models, 2560 J/cm² RL significantly prevented melanoma growth and increased the expression of CD103+ dendritic cells. 1280 and 1920 J/cm² RL decreased tumor volume, but not significantly. RL did not cause skin inflammation or erythema in normal skin.

Conclusion

RL represents a potentially safe and effective melanoma therapeutic. RL prevented tumor growth and increased the expression of immune markers, such as CD103, that are associated with favorable melanoma outcomes. Further research is needed to determine the optimal clinical treatment regimen for melanoma using RL.

The Effect of Low-level Laser Therapy on VEGF, IL-6 Expression and Viability of Oral Squamous Cell Carcinoma Cells

Low-level laser therapy has shown successful results in the prevention and treatment of oral mucositis. One of the concerns about low-level lasers is their effects on remaining malignant cells in the area. Interleukin-6 is a multifunctional cytokine that plays an important role in a wide range of biologic activities in increasing tumor functions, decreasing survival, and resistance to chemo-radiotherapy. Vascular-endothelial growth factor increases tumor vascularization. It has been shown in the previous studies that LLLT can cause an increase of IL-6 and VEGF in some cells. The present thesis aims to study the effects of LLLT on IL-6 and VEGF expression, as well as cell viability on OSCC cells. Tumorigenic cells of an oral squamous cell carcinoma cell line were irradiated with 3 different diode lasers, and were compared to the control group (660nm- 200mW-4J/cm2, 810nm-200mW-4J/cm2, 940nm-200mW-4J/cm2). MTT assay, ELISA, and RT-PCR were used to measure cell viability, IL-6, and VEGF expression. Cell viability of all laser-irradiated groups was significantly lower than the control group. VEGF expression increased in laser-irradiated groups. This was only significant in the 810nm group. IL-6 protein secretion was significantly higher in all laser-irradiated groups compared to the control group.

Tumor radiosensitization by photobiomodulation

PURPOSE

To investigate the safety of photobiomodulation therapy (PBM) in tumors and its potential as a radiosensitizer when combined with radiotherapy.

METHODS

We have performed in vitro experiments in A431 cells to assess proliferation and cell cycle after PBM, as well as clonogenic assay and H2AX-gamma immunolabeling to quantify double strand breaks after the combination of PBM and radiation. In vivo experiments in xenografts included Kaplan-Meier survival analysis, optical coherence tomography (OCT) and histological analysis.

RESULTS

PBM did not induce proliferation in vitro, but increased the G2/M fraction by 27% 24h after illumination, resulting in an enhancement of 30% in radiation effect in the clonogenic assay. The median survival of the PBM-RT group increased by 4 days and the hazard ratio was 0.417 (CI 95%: 0.173-1.006) when compared to radiation alone. OCT analysis over time demonstrated that PBM increases tumor necrosis due to radiation, and histological analysis showed that illumination increased cell differentiation and angiogenesis, which may play a role in the synergetic effect of PBM and radiation.

CONCLUSION

PBM technique may be one of the most appropriate approaches for radiosensitizing tumors while protecting normal tissue because of its low cost and low training requirements for staff.

Photobiomodulation With Blue Laser Inhibits Bladder Cancer Progression

Blue lasers are becoming more widely used in the diagnosis and treatment of bladder cancer; however, their photobiomodulation effects on bladder cancer cells remains unclear. The purpose of the current study was to explore the photobiomodulation effect of blue laser irradiation on bladder cancer progression and the associated mechanisms. The human uroepithelial cell line SV-HUC-1 and human bladder cancer cell lines T24 and EJ were exposed to blue laser irradiation (450 nm) at various energy densities, and cell proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and the levels of the proteins associated with the MAPK pathway proteins were determined. A significant decrease in cell viability was observed in a density-dependent manner after blue laser irradiation at > 4 J/cm² in both bladder cancer cell lines. However, the blue laser did not reduce cell viability in SV-HUC-1 cells until the energy density exceeded 16 J/cm². Meanwhile, Ki67 levels, reflecting cell proliferation and senescence, were also significantly decreased after blue laser irradiation at 4 J/cm² and 8 J/cm² in the absence of cell cycle arrest. Moreover, blue laser irradiation at 4 J/cm² and 8 J/cm² caused a reduction in cell migration and invasion and also reduced the expression levels of MMP-2, MMP-9, Snail, N-cadherin, phospho-MEK and phospho-ERK, and elevated the expression levels of E-cadherin. Meanwhile ERK activator(tBHQ) significantly reversed the irradiation-induced suppression of proliferation, migration and invasion in T24 and EJ cell lines. The present study showed that blue laser irradiation inhibited bladder cancer proliferation in a density-dependent manner and inhibited bladder cancer progression by suppressing migration, invasion, and the EMT process in T24 and EJ cell lines. This inhibition was possibly mediated via suppression of the MAPK/MEK/ERK pathway. Thus, the use of a low-energy blue laser in the diagnosis and treatment of bladder cancer is possibly safe and may have an anti-tumor effect.

Photobiomodulation effects on photodynamic therapy in HNSCC cell lines

A combination of metabolic modifications by light stimulus and photodynamic action is very attractive. Photobiomodulation therapy (PBMT) comprehends a vast range of applications and has been shown to be suitable to ease morbidities caused by chemotherapy and radiation, such as mucositis and dermatitis. The current study investigates the effects of near-infrared PBMT combined with porphyrin-based photodynamic therapy (PDT) in squamous cell carcinoma cell lines SCC-25 and SCC-4. The aim is to evaluate the potential of this combination to improve PDT outcome by increasing cell toxicity. Many techniques were used to verify the combined effect. Photobiomodulation (PBM) enhanced PDT action in SCC-25 cells by increasing photosensitizer (PS) uptake and production of reactive oxygen species (ROS). The equivalent was not seen in SCC-4 cells compared to the PDT only group. We believe these effects are strongly related to the interval of application between PBMT, PS incubation and PDT. Additionally, the effect of ascorbic acid on preventing PBM effects in PDT shows that ROS play an important role in the early mechanisms of PBM-PDT. Therefore, we believe PBM-PDT combination is worth exploring, for its benefit-cost ratio and simple protocols, along with the possibility of improvement in treatment resuts.

Safety and efficacy of photobiomodulation therapy in oncology: A systematic review

We performed a systematic review of the current literature addressing the safety and efficacy of photobiomodulation therapy (PBMT) in cancer patients. In this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were used. In vitro, in vivo, and clinical studies, which investigated the effect of PBMT on cell proliferation/differentiation, tumor growth, recurrence rate, and/or overall survival were included. The Medline/PubMed, EMBASE, and Scopus databases were searched through April 2020. A total of 67 studies met the inclusion criteria with 43 in vitro, 15 in vivo, and 9 clinical studies identified. In vitro studies investigating the effect of PBMT on a diverse range of cancer cell lines demonstrated conflicting results. This could be due to the differences in used parameters and the frequency of PBM applications. In vivo studies and clinical trials with a follow‐up period demonstrated that PBMT is safe with regards to tumor growth and patient advantage in the prevention and treatment of specific cancer therapy‐related complications. Current human studies, supported by most animal studies, show safety with PBMT using currently recommended clinical parameters, including in Head & Neck cancer (HNC) in the area of PBMT exposure. A significant and growing literature indicates that PBMT is safe and effective, and may even offer a benefit in patient overall survival. Nevertheless, continuing research is indicated to improve understanding and provide further elucidation of remaining questions regarding PBM use in oncology.

Effects of 660-nm and 780-nm Laser Therapy on ST88-14 Schwann Cells

The aim of the present study was to evaluate the comparative effects of red (660-nm) and near-infrared (780-nm) low-level laser therapy (LLLT) on viability, mitochondrial activity, morphology and gene expression of growth factors on Schwann cells (SC). ST88-14 cells were grown in RPMI 1640 with 10 mM of HEPES, 2 mM of glutamine, 10% fetal bovine serum and 1% antibiotic-antimycotic solution at 37°C in humidified atmosphere of 5% CO₂ . Cells were detached with trypsin and centrifugated at 231 g for 5 min at 10°C, and the pellet (8 × 10⁴  cells/tube) was irradiated at the bottom of 50 ml polypropylene tube with a Twin-Laser system (660 and 780 nm, 40 mW, 1 mW cm^-2 , 3.2 and 6.4 J, 80 and 160 J cm^-2 with 80 and 160 s). After 1, 3 and 7 days, the analysis was performed. After irradiation, the SC increase mitochondrial activity, gene expression of the neural growth factors NGF and BDNF, and cell migration and increase the G2/M cells. SC showed neuronal morphology, normal F-actin cytoskeleton organization and positive labeling for S100. PBM increased metabolic activity, mitosis and gene expression when irradiated with red and infrared LLLT. An increase in cell migration was obtained when irradiated with infrared LLLT.

Effects of photobiomodulation on cellular viability and cancer stem cell phenotype in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy; it has been shown that cancer stem cells (CSC) are present in OSCC and associated with tumor growth, invasion, metastasis, and therapeutic resistance. Photobiomodulation (PBM) is an alternative tool for oncologic treatment adverse effects such as oral mucositis (OM); however, controversy exists regarding the undesirable effects of PBM on tumor or CSC. This study aimed to evaluate in vitro, the effects of PBM, with the same dosimetric parameters as those used in the clinic for OM prevention and treatment, on OSCC cellular viability, as well as PBM's effect on CSC properties and its phenotype. OSCC cell lines were submitted to single or daily PBM with 3 J/cm² and 6 J/cm² and then the cellular viability was evaluated by MTT, NRU (neutral red uptake), and CVS (crystal violet staining). The CSC populations were evaluated by clonogenic formation assay, flow cytometry, and RT-qPCR. The single PBM with the 3 J/cm² group was associated with increased cellular viability. Daily PBM with 3 J/cm² and 6 J/cm² was associated with a significant decrease in cellular viability. Additionally, daily PBM was not able to promote CSC self-renewal or the CD44^high/ESA^low and CD44^high/ESA^high cellular phenotypes. Moreover, a decrease in the number of spheres and in the expression of the CSC related gene BMI1 was observed after daily PBM with 6 J/cm². Daily PBM with 3 J/cm² and 6 J/cm² showed an inhibitory effect on cellular viability and was not able to promote the CSC self-renewal or phenotype.

Review on the Cellular Mechanisms of Low-Level Laser Therapy Use in Oncology

Photobiomodulation (PBM) using low-level laser therapy (LLLT) is a treatment that is increasingly used in oncology. Studies reported enhancement of wound healing with reduction in pain, tissue swelling and inflammatory conditions such as radiation dermatitis, oral mucositis, and lymphedema. However, factors such as wavelength, energy density and irradiation frequency influence the cellular mechanisms of LLLT. Moreover, the effects of LLLT vary according to cell types. Thus, controversy arose as a result of poor clinical response reported in some studies that may have used inadequately planned treatment protocols. Since LLLT may enhance tumor cell proliferation, these will also need to be considered before clinical use. This review aims to summarize the current knowledge of the cellular mechanisms of LLLT by considering its effects on cell proliferation, metabolism, angiogenesis, apoptosis and inflammation. With a better understanding of the cellular mechanisms, bridging findings from laboratory studies to clinical application can be improved.

Photobiomodulation Therapy in Oral Mucositis and Potentially Malignant Oral Lesions: A Therapy Towards the Future

Photobiomodulation therapy (PBMT) is an effective treatment modality, which has the significant advantage of enhancing a patient’s quality of life (QoL) by minimising the side effects of oral cancer treatments, as well as assisting in the management of potentially cancerous lesions. It is important to note that the major evidence-based documentation neither considers, nor tackles, the issues related to the impact of PBMT on tumour progression and on the downregulation of cellular proliferation improvement, by identifying the dose- and time-dependency. Moreover, little is known about the risk of this therapy and its safety when it is applied to the tumour, or the impact on the factor of QoL. The review aimed to address the benefits and limitations of PBMT in premalignant oral lesions, as well as the conflicting evidence concerning the relationship between tumour cell proliferation and the applied dose of photonic energy (fluence) in treating oral mucositis induced by head and neck cancer (H&N) treatments. The objective was to appraise the current concept of PBMT safety in the long-term, along with its latent impact on tumour reaction. This review highlighted the gap in the literature and broaden the knowledge of the current clinical evidence-based practice, and effectiveness, of PBMT in H&N oncology patients. As a result, the authors concluded that PBMT is a promising treatment modality. However, due to the heterogeneity of our data, it needs to undergo further testing in well-designed, long-term and randomised controlled trial studies, to evaluate it with diligent and impartial outcomes, and ensure laser irradiation’s safety at the tumour site.

The impact of photobiomodulation therapy on the biology and behavior of head and neck squamous cell carcinomas cell lines

Photobiomodulation therapy (PBMT) is an emerging therapeutic modality designed to prevent and treat chemotherapy-driven oral mucositis (OM). However, the response of tumor cells to the effects of PBMT remains poorly understood. Our study explores the effects of PBMT in head and neck squamous cell carcinoma (HNSCC) based on cellular proliferation, migration, and survival of tumor cells and its population of cancer stem cells (CSC). We explored the behavior of two HNSCC cell lines (HN6 and HN13) under two distinct conditions, a physiological growing condition (10% FBS), and under stress growing condition (2% FBS) prior to irradiation using diode laser (InGaAlP; MM Optics, São Carlos, SP, Brazil). Diode laser (660 nm) was applied with a power of 100 mW delivering a total energy per point of 0.24 J. MTT and wound healing test (scratch assay) were performed to evaluate, respectively, proliferation and migration of tumor cells. Clonogenic and spheres formation assays were also performed to evaluate the survival and percentage of CSC upon irradiation. Overall, we observed that PBMT does not exacerbate the behavior of HNSCC. We could only observe a decrease in cellular proliferation of one cell line (HN6) when cultured under nutritional stress conditions (p < .05). There were no significant differences between the control and the PBMT groups regarding cell migration, survival and the percentage of CSC. Collectively, our results suggest that in vitro administration of PBMT to HNSCC does not modify the behavior of tumor cells.

Early tongue carcinomas (clinical stage I and II): echo-guided three-dimensional diode laser mini-invasive surgery with evaluation of histological prognostic parameters. A study of 85 cases with prolonged follow-up

The management of patients with early stage (cT1-T2) tongue squamous cell carcinoma without clinicoradiologic evidence of neck node metastasis (cN0) has been widely debated over the last 3 decades and still remains controversial. Nevertheless, the identification of patients with low-stage tumours at high-risk for occult cervical metastases is imperative before planning treatments of primary tumours, as well as that of prognostic markers which may possibly select those patients who may benefit of additional workup after surgery in view of the high metastatic potential of the primary tumour. The pre-surgical evaluation of tongue malignant primary tumour (for assessing lateral and deep margins) along with diode laser surgery (with accurate incision, bleeding-free and with reduced/absent post-surgical complications) may lead to a more conservative but equally decisive surgical treatment, also with a greater patient compliance. We studied 85 consecutive cases of cT1-T2 N0 tongue squamous cell carcinoma who had been managed by the following diagnostic/therapeutic protocol: pre-operative high definition ultrasound examination for the evaluation of size and depth, followed by three-dimensional surgical excision by diode laser (wavelength of 800 ± 10 nm, output power of 8 W in continuous wave, flexible optic fibre of 320 μm in contact mode) and detailed histological analyses of well-established prognostic parameters (tumour grade, thickness, depth, front of infiltration and surgical margins) with statistical analysis. No post-surgical photobiomodulation was performed. Overall, 58.82% of patients were stage I, 18% stage II, and the most frequent histotype was squamous cell carcinoma (97.64%). Large nests invasion pattern was observed in 64 cases, expansive pattern in 9, invasion in single cells in 12; front of invasion involved the muscle in 62 cases, vessels in 6, nerves in 15; peritumoural vascular invasion was assessed in 6 patients and perineural invasion in 15. Selective neck lymphadenectomy was performed in 9 cases, and clinically occult node metastases were detected in two cases. At follow-up, 78 patients (98.73%) were alive and free of disease, one patient experienced tumour-related death, while the remaining 6 died for non-disease-related causes. All the histological prognostic parameters were statistically significant (χ² test; p = 0.05), thus leading to a prognostic weight classification with a three-tiered stratification. On the bases of these results, the authors maintain that the reported diagnostic/therapeutic protocol, including the pre-operative echo-guided three-dimensional evaluation, the following diode laser mini-invasive surgery for tumour excision and the histological examination along with the proposed three-tiered stratification of histological prognostic parameters may allow proper management of clinical stage I and II early tongue carcinomas.

Red LED Light Is Influenced by IL-6 to Promote the Migration Ability of Oral Squamous Cell Carcinoma Cell Line

AIM

The purpose of this study was to search for the influence of red LED light of oral squamous cell carcinoma cells (OSCC) Material & Methods: HSC-3 was irradiated with red LED light (630 nm/3 J). Proliferative capacity was analyzed using WST-1. Transwell migration assay, real-time PCR, and ELISA method were also used to analyze migratory ability.

CONCLUSIONS

HSC-3 cells irradiated with red LED light showed increased migration ability. Interestingly, we clarified that the expression of Interleukin-6 (IL-6), which promotes the migratory ability of cancer cells, is induced.

Examining tumor modulating effects of photobiomodulation therapy on head and neck squamous cell carcinomas

The aim of the present systematic review was to analyze studies that investigated the effects of photobiomodulation therapy on head and neck squamous cell carcinoma cells.