Modulation of alpha 4 beta 1 and alpha 5 beta 1 integrin expression: heterogeneous effects of Q-switched ruby, Nd:YAG, and alexandrite lasers on melanoma cells in vitro

Optimal management of common acquired melanocytic nevi (moles): current perspectives

Although common acquired melanocytic nevi are largely benign, they are probably one of the most common indications for cosmetic surgery encountered by dermatologists. With recent advances, noninvasive tools can largely determine the potential for malignancy, although they cannot supplant histology. Although surgical shave excision with its myriad modifications has been in vogue for decades, the lack of an adequate histological sample, the largely blind nature of the procedure, and the possibility of recurrence are persisting issues. Pigment-specific lasers were initially used in the Q-switched mode, which was based on the thermal relaxation time of the melanocyte (size 7 μm; 1 μsec), which is not the primary target in melanocytic nevus. The cluster of nevus cells (100 μm) probably lends itself to treatment with a millisecond laser rather than a nanosecond laser. Thus, normal mode pigment-specific lasers and pulsed ablative lasers (CO2/erbium [Er]:yttrium aluminum garnet [YAG]) are more suited to treat acquired melanocytic nevi. The complexities of treating this disorder can be overcome by following a structured approach by using lasers that achieve the appropriate depth to treat the three subtypes of nevi: junctional, compound, and dermal. Thus, junctional nevi respond to Q-switched/normal mode pigment lasers, where for the compound and dermal nevi, pulsed ablative laser (CO2/Er:YAG) may be needed. If surgical excision is employed, a wide margin and proper depth must be ensured, which is skill dependent. A lifelong follow-up for recurrence and melanoma is warranted in predisposed individuals, although melanoma is decidedly uncommon in most acquired melanocytic nevi, even though histological markers may be seen on evaluation.

Low-level laser therapy in secondary lymphedema after breast cancer: systematic review

Complex physical therapy is the main treatment for the secondary lymphedema after breast cancer. The low-level laser therapy (LLLT) has been used in order to stimulate lymphangiogenesis, encourage lymphatic motility, and reduce lymphostatic fibrosis. However, these factors could also favor the development of recurrence and metastasis. The objective of this study is to discuss the use of LLLT in the treatment of lymphedema after breast cancer. This study utilized a systematic review on the use of LLLT in the treatment of lymphedema after breast cancer. Evaluating quality of articles was conducted through the PEDro scale. Of the 41 articles identified, four were considered to be of high methodological quality (score ≥ 5). The low-level laser in the axillary region was performed in all studies. The control group was not similar across studies. The results presented showed that there was a reduction in limb volume in the group subjected to low-power laser when compared with other treatments. No studies have evaluated the risk of metastasis or relapse in the irradiated areas. Because no studies have included the complex physical therapy as the comparison group, we cannot claim that laser treatment is the best efficacy or effectiveness in lymphedema treatment after breast cancer. No studies have evaluated the hypothesis that the LLLT can increase the risk of recurrence or metastasis. Therefore, the questions about the safety of this procedure in cancer patients remain.

Congenital melanocytic nevi: where are we now? Part II. Treatment options and approach to treatment

Treatment of congenital melanocytic nevi (CMN) is generally undertaken for 2 reasons: (1) to reduce the chances of cutaneous malignant melanoma and (2) for cosmetic reasons. Over the past century, a large number of treatments for CMN have been described in the literature. These include excision, dermabrasion, curettage, chemical peels, radiation therapy, cryotherapy, electrosurgery, and lasers. Only low-level evidence supporting these approaches is available, and large randomized controlled trials have not been published. This article explores therapeutic controversies and makes recommendations based on the best available evidence.

Lentigines, laser, and melanoma: a case series and discussion

Solar lentigines are considered one of the earliest signs of photoaging and are an extremely common cosmetic complaint. Successful removal of these lesions can be achieved with laser and non-laser light sources, and is one of the most frequently performed cosmetic procedures in laser centers. Distinguishing a benign lentigo from other pigmented lesions can sometimes be challenging, even for a trained dermatologist. We report a series of three patients who presented to our laser center within 2 months of one another for cosmetic removal of pigmented lesions that were found to be melanoma. One patient was referred by another dermatologist, one by a physician family member, and the other presented on his own. These cases highlight the need for careful evaluation of pigmented lesions prior to laser treatment, regardless of the source of the referral. In this article, we will review the diagnostic and treatment differences between lentigines and their malignant counterparts, and examine the role of laser in both.

Gene expression under laser and light-emitting diodes radiation for modulation of cell adhesion: Possible applications for biotechnology

Experimental data about the modulation of adhesion and proliferation of anchorage-dependent HeLa cells with monochromatic or quasimonochromatic radiation in red to near-infrared region are presented. Cell adhesion and proliferation can be increased by irradiation with light of certain wavelengths (maxima in action spectrum are 619, 675, 740, 760, and 820 nm) or decreased when the activity of photoacceptor (cytochrome c oxidase in mitochondrial respiratory chain) is inhibited by chemicals before the irradiation. This modality allows controlling the number of attached and/or proliferating cells. Possible biotechnology applications of this method are outlined.

The effect of low-level laser irradiation (In-Ga-Al-AsP - 660 nm) on melanoma in vitro and in vivo

BACKGROUND

It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation.

METHODS

We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation. The in vivo mouse model (male Balb C, n = 21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660 nm 50 mW CW laser, beam spot size 2 mm(2), irradiance 2.5 W/cm(2) and irradiation times of 60s (dose 150 J/cm(2)) and 420s (dose 1050 J/cm(2)) respectively.

RESULTS

There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48 +/- 1.40% and 4.26 +/- 0.60%) at 72 h post-irradiation. This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150 J/cm(2) dose group were not significantly different from controls. For the 1050 J/cm(2) dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups.

CONCLUSION

LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5 W/cm(2)) and high dose (1050 J/cm(2)) significantly increases melanoma tumor growth in vivo.

Recurrent pigmented macules after q-switched alexandrite laser treatment of congenital melanocytic nevus

BACKGROUND

Q-switch-mode laser treatment of congenital nevi does not result in complete histological clearance, and many patients have partial repigmentation within several months. In addition, the number of recurrent pigmented macules (RPMs) may increase, a major drawback to good cosmetic results. While the mechanism of recurrence is not known.

OBJECTIVE

To help elucidate the mechanism of RPM development, we evaluated the expression of TNF-alpha and E-cadherin on RPM after treatment of congenital nevi with a Q-switched alexandrite laser (QSAL).

METHODS

Thirteen Korean subjects with congenital nevi received QSAL treatment at intervals ranging from 2 to 6 months (mean, 4.5 treatments). Two-millimeter punch biopsy specimens were obtained at their first visit and from RPMs 3-6 months after the last treatment. Expression of E-cadherin and TNF-alpha were determined histochemically in the original nevi and RPM. In addition, one RPM was examined by electron microscopy.

RESULTS

Reduced pigmentation in the treated areas was seen in all cases, but partial repigmentaion was seen as black spots within 6 months after the last QSAL treatment. Compared to the original nevi, the RPMs had increased numbers of melanocytes in the epidermis and reduced nevomelanocytic nests in the dermis. The expression of TNF-alpha and E-cadherin was downregulated in the RPMs compared to the original nevi. Electron microscopy confirmed the increase in melanocytes in the epidermis of RPMs.

CONCLUSION

Our findings suggest that the down-regulation of E-cadherin and TNF-alpha may induce the proliferation of melanocytes, resulting in the formation of RPMs.

In vitro study examining the effect of sub-lethal QS 755 nm lasers on the expression of p16INK4a on melanoma cell lines

BACKGROUND AND OBJECTIVES

Q-switched lasers had been used in the treatment of lentigo maligna but their role remains controversial. While previous studies have addressed the change in adhesion molecule expression after sub-lethal laser damage, no study has addressed the impact of sub-lethal laser damage at a molecular level. The p16 gene has been proposed as the candidate gene for melanoma. Our objective is to examine the effect of sub-lethal laser damage on p16 expression in melanoma cell lines.

STUDY DESIGN/MATERIALS AND METHODS

Three human melanoma cell lines-HTB 66, Sk-mel-24 (HTB 71), and G361-were irradiated by a Q-switched 755 nm Alexandrite laser at fluencies that ranged from 0.85 to 2.0 J/cm(2). HTB 66 was the only cell line with significant expression of p16INK4a while the other two cells lines were p16INK4a negative and served as negative control. Protein and mRNA expression for p16 were assessed by flow cytometry and RT-PCR, respectively.

RESULTS

The level of p16INK4a protein in cell line HTB 66 increased significantly after laser irradiation as compared with non-irradiated cells. The level of p16INK4a protein did not change in p16INK4a-negative cell lines (Sk-mel-24 and G361). However, there was only a slight increase in the percentage of G0/G1 phase cells.

CONCLUSIONS

Sub-lethal laser damage could increase DNA damage leading to an increase in p16 expression, and such effect would be particularly undesirable for patients with p16 mutation. Further studies are warranted to examine the role of sub-lethal laser damage in inducing p16 mutation.

Cell attachment to extracellular matrices is modulated by pulsed radiation at 820 nm and chemicals that modify the activity of enzymes in the plasma membrane

BACKGROUND AND OBJECTIVES

Adhesive interactions between cells and extracellular matrices play a regulative role in wound repair processes. The objective of this investigation is to study action mechanisms of pulsed radiation at 820 nm on cellular adhesion in vitro. Light emitting diodes (LED) at 820 nm are widely used for treatment of wounds of various etiology.

STUDY DESIGN/MATERIALS AND METHODS

The LED (820 +/- 10 nm, 10 Hz, 16-120 J/m(2)) is used for the irradiation of HeLa cell suspension. In parallel experiments, amiloride (5 x 10(-4) M), ouabain (7 x 10(-5) M, 7 x 10(-4) M), quinacrine (6 x 10(-4) M), arachidonic acid (1 x 10(-5) M), glucose (2 x 10(-4) M), and ATP (5 x 10(-5) M) are added to the cell suspension before or after the irradiation procedure. The cell-glass adhesion is studied using the adhesion assay technique described in Lasers Surg Med 1996; 18:171.

RESULTS

Cell-glass adhesion increases in a dose-dependent manner following the irradiation. Preirradiation eliminates the inhibition of cell attachment caused by ouabain, arachidonic acid, and ATP. The inhibitive effect of quinacrine on the cell attachment is eliminated by the irradiation performed after the treatment with the chemical. Irradiation and amiloride have a synergetic stimulative effect on the cell attachment. The threshold dose for the cell attachment stimulation by the irradiation is decreased by the treatment of the cell suspension with amiloride or ouabain.

CONCLUSIONS

The results obtained indicate that pulsed IR radiation at 820 nm increases the cell-matrix attachment. It is the modulation of the monovalent ion fluxes through the plasma membrane and not the release of arachidonic acid that is involved in the cellular signaling pathways activated by irradiation at 820 nm. Preirradiation has a protective effect against the inhibitive action of ouabain, arachidonic acid, ATP, and quinacrine on cell attachment process. It is supposed that irradiation activates those signaling pathways in cells which attenuate the inhibitive action of these chemicals.

Cell attachment modulation by radiation from a pulsed light diode (lambda = 820 nm) and various chemicals

BACKGROUND AND OBJECTIVE

Adhesive interactions between cells and extracellular matrices play a regulative role in wound repair processes. The objective of this investigation is to study the mechanisms of light action on cellular adhesion in vitro. The adhesion of HeLa cells to a glass matrix is evaluated after irradiation with a pulsed near-infrared (IR) diode and treatment with various chemicals.

STUDY DESIGN/MATERIALS AND METHODS

A semiconductor diode (820 +/- 10 nm, 10Hz, 16--120 J/m(2)) is used for irradiation of the cell suspension. In parallel experiments, various chemicals (mannitol, melatonin, ethanol, ascorbic acid, superoxide dismutase, catalase, rotenone, azide, dinitrophenol (DNP), methylene blue, and hydrogen peroxide) are added to the cell suspension before or after the irradiation procedure. The cell-glass adhesion is studied by using the adhesion assay technique (Lasers Surg. Med. 1996;18:171).

RESULTS

It has been found that cell-glass adhesion increases in a dose-dependent manner after irradiation. The treatment of the cells with antioxidants (free radical scavengers), e.g., mannitol, melatonin, ethanol, and ascorbic acid, as well as with the ionophore DNP, eliminated the light effect. The respiratory chain inhibitors rotenone and azide strongly modified the light effect, depending on the dose. The oxidative agents hydrogen peroxide (in a low concentration) and methylene blue increased the cell adhesion. Superoxide dismutase did not modify the light effect. The effect of the catalase (stimulative or suppressive) was dependent on its concentration and treatment sequence. Preirradiation was found to decrease (or normalize to the control level) the suppressive effects of some chemicals.

CONCLUSION

The results obtained are evidence that first, pulsed IR radiation with certain parameters modulates the cell-matrix attachment. second, free radical and redox processes are involved in the cell-matrix interaction, probably at some stage(s) of the photosignal transduction. Third, both types of the primary reactions in the respiratory chain, namely, the increase of the electron flow and production of the reactive oxygen species, cause a transient oxidative stress in the cytoplasm.

Lasers for the dermatologist

This article reviews the current uses of lasers in dermatological practice. It outlines safety issues and legislation and attempts to summarize the relevant physics and light interactions. The article is divided into sections pertaining to selective photothermolysis of structures containing the major skin chromophores: haemoglobin, melanin and water. The lasers used and conditions treated are discussed with reference to a literature review.

Sub-lethal effects of exposing the human melanoma cell line SKmel-23 to 532 nm laser light

The human melanoma cell line SKmel-23 has been used to investigate the sub-lethal damage that can occur as a result of exposing melanin containing cells to light (532 nm) from a frequency doubled Q-switched (Nd:YAG) laser. A dose response curve was obtained, which indicates that at energy levels of 0.6 J/cm2 and below no effect on either the viability or growth rate of the cell line was observed. Above this, cells rapidly died and at an energy level of 2.0 J/cm2, only approximately 15% of cells survived. This contrasts with the effects on the G361 melanoma line, which contains far less melanosomes, as an LD50 for this cell line was approximately 5.5 J/cm2. Exposing SKmel-23 cells to 0.4 J/cm2 of 532 nm light results in a diminution of the number of melanosomes within cells as well as a marked decrease in melanin content, as determined by spectrophotometric assay and electron microscopy. Using the reverse transcriptase polymerase chain reaction technique, the reduction in melanin content of the cells was accompanied by a selective decrease in mRNA coding for tyrosinase, the first enzyme in the biosynthetic pathway for melanin. No decrease in the mRNA coding for the GAPDH protein was observed. Our finding has implications for understanding the control processes that regulate the melanin content of cells and suggests that the model described can be used to further investigate changes that may occur in cells as a result of their exposure to sub-lethal levels of laser light.

Treatment of nevus spilus with the Q-switched ruby laser

BACKGROUND

Q-switched lasers have shown to be effective in the removal of unwanted cutaneous pigmentation. Benign cutaneous pigmented lesions represent a heterogeneous group. Nevus spilus is a relatively uncommon pigmented lesion characterized by dark, hyperpigmented dots scattered over a tan-colored macule.

OBJECTIVE

A cohort of patients with nevus spilus was studied to determine the effects of Q-switched ruby and Q-switched Nd:YAG laser treatment on clearance of pigment and to evaluate potential side effects.

METHODS

Six patients with nevus spilus were treated with the Q-switched ruby laser (QSR). In addition, three lesions received a test treatment with the Q-switched Nd:YAG (QSYAG) laser at 532 or 1064 nm. The results of treatment were documented during follow up visits.

RESULTS

Most lesions showed a near-complete or complete response to laser treatment. In one case partial hyperpigmentation occurred after treatment and in one case no follow-up could be obtained. In the three cases that received both QSR and QSYAG laser treatment, the QSR laser was shown to be the most effective in removing pigment.

CONCLUSION

Nevus spilus can be treated effectively with the Q-switched ruby laser.