Fractional Laser Releases Tumor-Associated Antigens in Poorly Immunogenic Tumor and Induces Systemic Immunity

The evolving landscape of laser-based skin cancer prevention

In the United States, 1 in 5 Americans develop keratinocyte carcinoma (KC) by age 70, placing the disease among the five most expensive cancers based on Medicare expenditure. Current preventative measures have failed to stem rising KC rates, highlighting the need for alternative strategies. Evolving evidence indicates that lasers conventionally used to treat photoaging, may provide protective effects against the development of KC and precursor lesion, actinic keratosis (AK). This review first delves into existing evidence on fractional infrared laser-based KC and AK prevention. Next, the work discusses potential underlying mechanisms that might explain fractional infrared lasers' prophylactic effects. A comprehensive literature search of PubMed and Web of Science databases was conducted from inception to April 2024 using preselected search terms. Interventional human and animal studies, epidemiological analyses, and case reports on fractional infrared laser-based prevention of KC or AK were screened according to predefined inclusion/exclusion criteria. Included evidence demonstrates that ablative fractional lasers reduce and delay development of AK/KC, shown in two controlled trials of photodamaged patients and two murine studies (i.e. Er: YSGG and CO2 lasers). Weaker evidence of KC prevention by nonablative infrared lasers is provided by a retrospective cohort study. In the laser literature, three mechanisms are proposed to drive these prophylactic effects, including the ability of infrared lasers to (i) remove DNA-damaged epidermal cells, (ii) activate the insulin-like growth factor-1 pathway by reducing fibroblast senescence, and (iii) initiate immunomodulating effects. Based on current evidence, infrared fractional lasers show promise particularly for secondary KC prevention in photodamaged populations.

Cutaneous Immune Responses to Ablative Fractional Laser, Heat- and Cold-Based Dermatological Procedures

OBJECTIVE

Physical treatment modalities, such as ablative fractional laser (AFL), electrocautery, and cryotherapy, are extensively used in the field of dermatology. This study aimed to characterize the short-term innate and adaptive immune responses induced by AFL compared with heat- and cold-based procedures.

MATERIALS AND METHODS

Innate (CD11b+Ly6G+ neutrophils) and adaptive (CD8+CD3+ T cells) immune cell infiltration and histopathological changes were examined in murine skin on Days 1 and 7, following AFL, monopolar-electrocautery (RF), thermocautery, and cryotherapy. Interventions were standardized to reach the reticular dermis. Clinical skin reactions were photo-documented daily. As a comparator, the adaptive immune response was examined in murine basal cell carcinomas (BCC) on Day 7 after AFL exposure.

RESULTS

Baseline histopathology confirmed immediate deep dermal tissue impact by all procedures. Immune cell dynamics varied across treatments throughout the progression of clinical and histopathological responses. On Day 1, AFL and heat-based procedures triggered an innate immune response, characterized by CD11b+Ly6G+ neutrophil cell infiltration that correlated with histopathological findings and immediate onset of clinical skin reactions. In addition, heat-based procedures led to an increase in overall dermal CD45+ cells (Day 1), which continued to rise for AFL and RF-electrocautery at Day 7 posttreatment. On the contrary, cryotherapy did not induce immediate (Day 1) innate immune responses, but instead a delayed increase in neutrophil and CD45+ cell infiltration (Day 7), which coincided with the late onset of clinical reaction. CD3+ T cells and CD8+CD3+ T cells demonstrated a similar pattern, with an increase observed for heat-based procedures on Day 1 and a delayed increase for cryotherapy on Day 7. Distinctive for AFL-treated skin, the level of dermal CD3+ T cells increased over time, significant by Day 7, and AFL-treated mouse BCCs responded with increased CD8+ T cell infiltration at Day 7 posttreatment.

CONCLUSION

Heat- and cold-based procedures developed distinct cutaneous immune responses, with cryotherapy resulting in a delayed response compared to immediate immune responses from heat-based procedures. The substantial T cell response induced by AFL in the skin and BCC tumors indicates a potential for AFL as an adjuvant in immunotherapeutic treatments of keratinocyte cancers.

Ablative fractional laser treatment reduces hedgehog pathway gene expression in murine basal cell carcinomas

This study aimed to investigate the impact of ablative fractional laser (AFL) on hedgehog pathway gene expression in murine microscopic basal cell carcinomas (BCCs) and compare these results to the effect of topical treatment with vismodegib, an FDA-approved hedgehog inhibitor. In 25 mice, 1 cm2 skin test sites (n = 44) containing microscopic BCCs were exposed to one of three interventions: a single CO2 AFL treatment (1 pulse, 40 mJ/microbeam, wavelength 10.6 μm, 5% density, pulse rate 250 Hz, n = 12), eight topical vismodegib treatments (3.8 mg/mL, n = 8), or combination of AFL and vismodegib treatments (n = 9). Untreated controls were included for comparison (n = 15). After 4 days, skin samples were analyzed for hedgehog gene expression (Gli1, Gli2, and Ptch1) by qPCR and vismodegib concentrations by liquid chromatography mass spectrometry (data analyzed with two-tailed t-tests and linear regression). A single treatment with AFL monotherapy significantly reduced hedgehog gene expression compared to untreated controls (Gli1 72.4% reduction, p = 0.003; Gli2 55.2%, p = 0.010; Ptch1 70.9%, p < 0.001). Vismodegib treatment also reduced hedgehog gene expression (Gli1 91.6%; Gli2 83.3%; Ptch1 83.0%), significantly surpassing AFL monotherapy for two out of three genes (Gli1, p = 0.017; Gli2, p = 0.007; Ptch1, p = 0.15). AFL and vismodegib combination mirrored the effects of vismodegib monotherapy (Gli1, p = 0.424; Gli2, p = 0.289; Ptch1, p = 0.593), possibly due to comparable cutaneous vismodegib concentrations (mean ± SD, vismodegib monotherapy 850 ± 475 µmol/L; combination 1036 ± 824 µmol/L; p = 0.573). In conclusion, a single AFL treatment significantly reduced hedgehog gene expression in murine BCCs mimicking the effects of eight topical applications of vismodegib. Further studies are needed to assess whether AFL can be utilized for BCC treatment, either as monotherapy or in combination with other drugs.

Anti-PD-1 immunotherapy with adjuvant ablative fractional laser displays increased tumour clearance of squamous cell carcinoma, a murine study

PD-1 checkpoint inhibitors are used as systemic immunotherapy for locally advanced and metastatic cutaneous squamous cell carcinoma (SCC); however, improved treatment efficacy is urgently needed. In this study, we aimed to investigate the effect of combining systemic anti-PD-1 treatment with adjuvant ablative fractional laser (AFL) in a spontaneous SCC mouse model. Tumours induced by ultraviolet radiation in the strain C3.Cg-Hrhr /TifBomTac were divided into four groups: anti-PD-1-antibody+AFL (n = 33), AFL alone (n = 22) anti-PD-1-antibody alone (n = 31) and untreated controls (n = 46). AFL was given at Day 0 (100 mJ/mb, 5% density), while anti-PD-1-antibody (ip, 200 μg) at Days 0, 2, 4, 6 and 8. Response to treatment was evaluated by tumour growth, survival time and by dividing response to treatment into complete responders (clinically cleared tumours), partial responders (reduced tumour growth rate compared to untreated controls) and non-responders (no decrease in tumour growth rate compared to untreated controls). The strongest tumour response was observed following the combination of systemic anti-PD-1 treatment combined with laser exposure, resulting in the highest percentage of complete responders (24%) compared with untreated controls (0%, p < 0.01), AFL monotherapy (13%, p > 0.05) and anti-PD-1-antibody monotherapy (3%, p > 0.05). Moreover, all three treatment interventions demonstrated significantly reduced tumour growth rates compared with untreated controls (p < 0.01), and the mice had significantly longer survival times (p < 0.01). In conclusion, the combination treatment revealed an improved treatment effect that significantly enhanced the complete tumour clearance not observed with the monotherapies, indicating a possible additive effect of anti-PD-1 with adjuvant AFL in treatment of SCC.

Oncolytic adenovirus coding for shedding-resistant MICA enhances immune responses against tumors

Cancer immunotherapies strive to overcome tumor-induced immune suppression and activate antitumor immune responses. Although cytotoxic T lymphocytes (CTLs) play a pivotal role in this process, natural killer (NK) cells have also demonstrated remarkable tumor-killing abilities, given their ability to discriminate tumor cells from normal cells and mediate specific antitumoral cytotoxicity. NK cells activation depends on a balance between activation and inhibition signals from several ligands/receptors. Among them, MICA/NKG2D axis is a master regulator of NK activation. MHC class I chain-related polypeptide A (MICA) expression is upregulated by many tumor cell lines and primary tumors and serves as a ligand for the activating NK group 2D (NKG2D) receptor on NK cells and subpopulations of T cells. However, cancer cells can cleave MICA, making it soluble and de-targeting tumor cells from NK cells, leading to tumor immune escape.In this study, we present ICOVIR15KK-MICAMut, an oncolytic adenovirus (OAdv) armed with a transgene encoding a non-cleavable MICA to promote NK-mediated cell-killing capacity and activate the immune response against cancer cells. We first demonstrated the correct MICA overexpression from infected cells. Moreover, our MICA-expressing OAdv promotes higher NK activation and killing capacity than the non-armed virus in vitro. In addition, the armed virus also demonstrated significant antitumor activity in immunodeficient mice in the presence of human PBMCs, indicating the activation of human NK cells. Finally, OAdv-MICA overexpression in immunocompetent tumor-bearing mice elicits tumor-specific immune response resulting in a greater tumor growth control.In summary, this study highlights the significance of NK cells in cancer immunotherapy and presents an innovative approach using a modified oncolytic virus to enhance NK cell activation and antitumor immune response. These findings suggest promising potential for future research and clinical applications.

Feasibility of Intratumoral Anti-PD1 as Treatment of Human Basal Cell Carcinoma: An Explorative Study with Adjuvant Ablative Fractional Laser

The use of immune checkpoint inhibitors (ICI) is expanding with the approval for advanced/metastatic keratinocyte carcinoma; however, most tumors are non-aggressive. Local administration could broaden ICI, but adequate immune response might require an immune-attractive adjuvant such as ablative fractional laser (AFL). Accordingly, this study aimed to explore intratumoral injection of anti-PD1 with and without AFL in basal cell carcinoma (BCC), exploring anti-PD1 concentration, immune cell infiltration, tumor response, and safety. This open-label, proof-of-concept trial investigated intratumoral anti-PD1 + AFL combination therapy versus anti-PD1 or AFL monotherapy in 28 BCC patients. The primary endpoints were immune cell infiltration evaluated immunohistochemically and clinical tumor response after 3 months. The secondary outcomes were tumoral drug concentration and safety. The most robust response was obtained following intervention with combined anti-PD1+AFL, leading to a ~2.5-fold increase in CD3+ cells (p = 0.027), and tumor reduction ≥25% in 73%, including two tumors with complete remission. Upon anti-PD1 monotherapy, a slight decrease in CD3+ cells was observed while a non-significant increase following AFL was seen. Tumor reduction ≥25% was seen in 45% and 50%, respectively, after anti-PD1 and AFL monotherapy. The CD8/CD3 ratio remained unchanged after anti-PD1+AFL and anti-PD1 monotherapy, while AFL led to a decreased ratio. A non-significant decline in the Foxp3/CD3 ratio was observed for all groups. Side-effects were mild with no systemic drug concentration detected. Intratumoral anti-PD1 injection is feasible, and a single exposure to locally injected anti-PD1 with adjuvant AFL increased immune cell infiltration and reduction in BCC with limited side-effects.

Plasmodium infection suppresses colon cancer growth by inhibiting proliferation and promoting apoptosis associated with disrupting mitochondrial biogenesis and mitophagy in mice

BACKGROUND

Colon cancer is a common gastrointestinal tumor with a poor prognosis, and thus new therapeutic strategies are urgently needed. The antitumor effect of Plasmodium infection has been reported in some murine models, but it is not clear whether it has an anti-colon cancer effect. In this study, we investigated the anti-colon cancer effect of Plasmodium infection and its related mechanisms using a mouse model of colon cancer.

METHODS

An experimental model was established by intraperitoneal injection of Plasmodium yoelii 17XNL-infected erythrocytes into mice with colon cancer. The size of tumors was observed dynamically in mice, and the expression of Ki67 detected by immunohistochemistry was used to analyze tumor cell proliferation. Apoptosis was assessed by terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) staining, and the expression of apoptosis-related proteins including Bax, Bcl-2, caspase-9, and cleaved caspase-3 was detected by western blot and immunohistochemistry, respectively. Transmission electron microscopy (TEM) was used to observe the ultrastructural change in colon cancer cells, and the expression of mitochondrial biogenesis correlative central protein, PGC-1α, and mitophagy relevant crucial proteins, PINK1/Parkin, were detected by western blot.

RESULTS

We found that Plasmodium infection reduced the weight and size of tumors and decreased the expression of Ki67 in colon cancer-bearing mice. Furthermore, Plasmodium infection promoted mitochondria-mediated apoptosis in colon cancer cells, as evidenced by the increased proportion of TUNEL-positive cells, the upregulated expression of Bax, caspase-9, and cleaved caspase-3 proteins, and the downregulated expression of Bcl-2 protein. In colon cancer cells, we found destroyed cell nuclei, swollen mitochondria, missing cristae, and a decreased number of autolysosomes. In addition, Plasmodium infection disturbed mitochondrial biogenesis and mitophagy through the reduced expression of PGC-1α, PINK1, and Parkin proteins in colon cancer cells.

CONCLUSIONS

Plasmodium infection can play an anti-colon cancer role in mice by inhibiting proliferation and promoting mitochondria-mediated apoptosis in colon cancer cells, which may relate to mitochondrial biogenesis and mitophagy.

Anti-PD-1 Therapy with Adjuvant Ablative Fractional Laser Improves Anti-Tumor Response in Basal Cell Carcinomas

Simple Summary

In some mouse models, ablative fractional laser (AFL) enhances the efficacy of anti-programmed cell death1 therapy (aPD-1), which was recently approved for basal cell carcinoma (BCC). In this explorative study, we aimed to assess locally applied AFL as an adjuvant to systemic aPD-1 treatment in a clinically relevant BCC model. BCC-carrying mice received aPD-1 alone, AFL alone, aPD-1+AFL, or no treatment. Both aPD-1 and AFL alone significantly increased survival time relative to the untreated controls, while aPD-1 that had been complemented with AFL further promoted survival and improved tumor clearance and growth rates. The BCCs were poorly immune infiltrated, but aPD-1 with adjuvant AFL and AFL alone induced substantial immune cell infiltration in tumors and increased the levels of relevant immune cell subtypes. Thus, the anti-tumor response that was generated by aPD-1 with adjuvant AFL may potentially be promoted by increased immune activity in tumors. In conclusion, the use of a local AFL adjuvant to systemic aPD-1 therapy could hold substantial promise for BCC treatment.

Abstract

The efficacy of anti-programmedcelldeath1therapy (aPD-1), which was recently approved for basal cell carcinoma (BCC) treatment, can be enhanced by adjuvant ablative fractional laser (AFL) in syngeneic murine tumor models. In this explorative study, we aimed to assess locally applied AFL as an adjuvant to systemic aPD-1 treatment in a clinically relevant autochthonous BCC model. BCC tumors (n = 72) were induced in Ptch1^+/−K14-CreER2p53^fl/fl-mice (n = 34), and the mice subsequently received aPD-1 alone, AFL alone, aPD-1+AFL, or no treatment. The outcome measures included mouse survival time, tumor clearance, tumor growth rates, and tumor immune infiltration. Both aPD-1 and AFL alone significantly increased survival time relative to untreated controls (31 d and 34.5 d, respectively vs. 14 d, p = 0.0348–0.0392). Complementing aPD-1 with AFL further promoted survival (60 d, p = 0.0198 vs. aPD-1) and improved tumor clearance and growth rates. The BCCs were poorly immune infiltrated, but aPD-1 with adjuvant AFL and AFL alone induced substantial immune cell infiltration in the tumors. Similar to AFL alone, combined aPD-1 and AFL increased neutrophil counts (4-fold, p = 0.0242), the proportion of MHCII-positive neutrophils (p = 0.0121), and concordantly, CD4⁺ and CD8⁺ T-cell infiltration (p = 0.0061–0.0242). These descriptive results suggest that the anti-tumor response that is generated by aPD-1 with adjuvant AFL is potentially promoted by increased neutrophil and T-cell engraftment in tumors. In conclusion, local AFL shows substantial promise as an adjuvant to systemic aPD-1 therapy in a clinically relevant preclinical BCC model.

Laser Immunotherapy: A Potential Treatment Modality for Keratinocyte Carcinoma

Simple Summary

In light of expanding incidences of keratinocyte carcinoma (KC) with many patients developing multiple tumors, the demand for new treatment modalities is high. With the approval of cemplimab for locally advanced and metastasizing basal cell carcinoma and squamous cell carcinoma, KC is now included as an indication for systemic immunotherapy. At present, however, systemic KC therapy remains limited by the severe side effects associated with treatment. Immunotherapy might be more broadly applied if locally administered. Localized to the skin, KCs are easily accessible to topical drugs and physical interventions such as laser. There is an increasing appreciation of lasers’ potential to activate an immune response. Further enhancement of the laser-based immune activation might be obtained by combining laser and immunotherapeutic agents, known as laser immunotherapy. In search of new treatment modalities for KC and aiming to broaden the field of KC immunotherapy, this review discusses the current literature on immune activation following both laser monotherapy and laser immunotherapy.

Abstract

The role of the immune system in cancer growth is well recognized and the development of immunotherapy represents a breakthrough in cancer treatment. Recently, the use of systemic immunotherapy was extended to keratinocyte carcinoma (KC), specifically locally advanced and metastasizing basal and squamous cell carcinoma. However, since most KC lesions are non-aggressive, systemic treatment with associated side effects is rarely justified. Conversely, topical immunotherapy with imiquimod remains restricted to premalignant and superficial lesions. Use of laser in the treatment of KC has evolved from physical tumor destruction and laser-assisted drug delivery to laser-mediated immune modulation. Evidence indicates that laser monotherapy can lead to immune cell infiltration, tumor reduction and resistance to tumor re-inoculation. Combining laser with immunotherapeutic agents, termed laser immunotherapy (LIT), may further potentiate immune activation and tumor response. Studies on LIT show not only direct anti-tumor effects but systemic adaptive immunity, illustrated by the prevention of tumor recurrence and regression in distant untreated tumors. These findings imply a therapeutic potential for both local and metastatic disease. This work provides rationales for immune-based treatment of KC and presents the current status of KC immunotherapy. Aiming to expand the field of KC immunotherapy, the review discusses the literature on immune activation following laser monotherapy and LIT.

Tumor Clearance and Immune Cell Recruitment in UV-Induced Murine Squamous Cell Carcinoma Exposed to Ablative Fractional Laser and Imiquimod Treatment

BACKGROUND AND OBJECTIVES

Keratinocyte carcinoma (KC) is the most common cancer worldwide, and squamous cell carcinoma (SCC) is the second most frequent subtype. Ablative fractional laser (AFL)-assisted drug delivery significantly enhances the uptake of topically applied drugs. The objective of this study was to assess tumor response and perform a descriptive characterization of the local recruitment of immune cells and systemic immune mediator levels in an ultraviolet radiation (UVR)-induced murine SCC model after AFL treatment alone and combined with topical imiquimod.

STUDY DESIGN/MATERIALS AND METHODS

Immunocompetent hairless mice (C3·Cg/TifBomTac, n = 74) were irradiated with solar-simulated UVR until 3-mm SCCs developed. The mice were divided into four interventional groups: AFL alone, AFL + imiquimod, imiquimod alone, and untreated SCC controls. AFL was given as a single treatment, whereas imiquimod was applied daily until the mice were euthanized on Days 0, 2, 7, or 14. SCCs were photographed and measured (mm) to assess the therapeutic response. Skin samples were processed for histopathological and immunohistochemical analyses, as well as for flow cytometry. Cytokine expression changes in sera were analyzed using ELISpot cytokine arrays.

RESULTS

Treatment of mouse SCCs with AFL + imiquimod induced the most robust immune cell infiltration and the greatest proportion of tumor clearance compared to other interventions. Early innate immune cell infiltration was induced by AFL + imiquimod treatment as the number of neutrophils and macrophages had increased fourfold within 2 days of treatment initiation compared with untreated SCC control mice (P < 0.05). AFL treatment alone had a more limited effect, with a fourfold increase in neutrophils (P < 0.05) but no significant increase in the number of macrophages. Correspondingly, treatment with AFL + imiquimod had the greatest effects on the adaptive immune cell recruitment: CD4⁺ T-helper cells increased threefold at Day 7 compared with untreated SCCs (P = 0.0001) and, notably, cytotoxic CD8⁺ T cells increased 14-fold at Day 14 (P = 0.0112). In addition, FOXP3⁺ regulatory T cells (Tregs) increased 14-fold at Day 7 (P = 0.0026), suggesting the resolution of the inflammatory infiltration. AFL treatment alone induced a moderate immune cell infiltration (a twofold increase in CD4⁺ T-helper cells, P = 0.0200; a threefold increase in CD8⁺ T cells, P = 0.0100; and a 14-fold increase in FOXP3⁺ Tregs at Day 14, P = 0.0021), whereas imiquimod alone did not significantly increase cell counts. AFL + imiquimod treatment increased CXCL12 serum levels threefold at Day 14 (P = 0.0200).

CONCLUSION

AFL treatment alone and in combination with imiquimod induces substantial tumor clearance associated with local recruitment of innate and adaptive immune cells in UVR-induced murine SCCs. These results may provide a basis for new immunotherapeutic approaches to KC treatment.

Topical Delivery of Nivolumab, a Therapeutic Antibody, by Fractional Laser and Pneumatic Injection

BACKGROUND AND OBJECTIVES

PD-L1 is a tumor ligand that binds to the PD-1 receptor on immune cells, thereby inhibiting the antitumor immune response. The antibody nivolumab is a PD-1 inhibitor, Food and Drug Administration approved for systemic treatment of several aggressive cancer types. Topically applied nivolumab may hold potential as a future strategy to treat keratinocyte cancer, but its molecular properties preclude unassisted topical uptake. The aim of this study was to investigate uptake and biodistribution of topically delivered nivolumab, assisted by two physical enhancement techniques with different delivery kinetics; ablative fractional laser (AFL) and electronically controlled pneumatic injection (EPI).

STUDY DESIGN/MATERIALS AND METHODS

In vitro porcine skin was exposed to CO₂ AFL (20 mJ/mb, 5% density), followed by passive diffusion of nivolumab in a Franz cell (1 mg/ml, 18 hours, n = 6) or treated with EPI (4 bar) for immediate delivery of nivolumab (1 mg/ml, 10 minutes, n = 6). The resulting nivolumab skin concentrations were quantified by enzyme-linked immunosorbent assay (ELISA) at three skin depths (100, 500, and 1500 µm), comparing the uptake from assisted delivery with intact skin. Biodistribution of nivolumab in the skin for all interventions was visualized by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and fluorescence microscopy.

RESULTS

Delivery of nivolumab by AFL-assisted passive diffusion and immediate EPI both resulted in significantly enhanced uptake of nivolumab in all skin depths compared with intact skin (P < 0.05). With AFL, nivolumab concentrations reached 86.3 µg/cm³ (100 µm), 105.8 µg/cm³ (500 µm), and 19.3 µg/cm³ (1500 µm), corresponding to 2-10% of the applied concentration, with the highest deposition in the mid dermis. Immediate EPI delivered 429.4 µg/cm³ (100 µm), 584.9 µg/cm³ (500 µm), and 295.9 µg/cm³ (1500 µm) into the skin, corresponding to 29-58% of the applied nivolumab concentration. From qualitative visualization of the biodistribution, it appeared that nivolumab distributed in a horizontal and continuous homogenous band in the upper and mid dermis through AFL-exposed skin, whereas EPI-delivery showed a deep focal deposition extending into the deep dermis.

CONCLUSIONS

AFL-assisted passive diffusion and immediate EPI-assisted delivery show the potential to deliver therapeutic antibodies locally. Future in vivo and pharmacokinetic studies would reveal the full potential for topical antibody delivery by energy-based devices. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Induction of antitumor immunity in mice by the combination of nanoparticle-based photothermolysis and anti-PD-1 checkpoint inhibition

Generation of durable tumor-specific immune response without isolation and expansion of dendritic cells or T cells ex vivo remains a challenge. In this study, we investigated the impact of nanoparticle-mediated photothermolysis in combination with checkpoint inhibition on the induction of systemic antitumor immunity. Photothermolysis based on near-infrared light-absorbing copper sulfide nanoparticles and 15-ns laser pulses combined with the immune checkpoint inhibitor anti-PD-1 antibody (αPD-1) increased tumor infiltration by antigen-presenting cells and CD8-positive T lymphocytes in the B16-OVA mouse model. Moreover, combined photothermolysis, polymeric conjugate of the Toll-like receptor 9 agonist CpG, and αPD-1 significantly prolonged mouse survival after re-inoculation of tumor cells at a distant site compared to individual treatments alone in the poorly immunogenic syngeneic ID8-ip1-Luc ovarian tumor model. Thus, photothermolysis is a promising interventional technique that synergizes with Toll-like receptor 9 agonists and immune checkpoint inhibitors to enhance the abscopal effect in tumors.

Ablative fractional laser-assisted treatments for keratinocyte carcinomas and its precursors-Clinical review and future perspectives

Keratinocyte carcinomas (KC) are the most common malignant human neoplasms. Although surgery and destructive approaches are first-line treatments, topical therapies are commonly used. Due to limited uptake of topical agents across the skin barrier, clearance rates are often sub-optimal. In pre-clinical investigations, ablative fractional laser (AFL)-assisted drug delivery has demonstrated improved uptake of topical drugs commonly used to treat KC. In 22 clinical trials, the effect of AFL-assisted treatments has been investigated for actinic keratosis (AK; n = 14), Bowen's disease (BD; n = 5), squamous cell carcinoma (n = 1), and basal cell carcinoma (n = 7). The most substantial evidence currently exists for AFL-assisted photodynamic therapy for the treatment of AK and BD. AFL improved 12-months follow-up clearance rates of photodynamic therapy from 45.0-51.0% to 78.5-84.8% for AK and from 50.0-55.3% to 87.0-87.5% for BD. AFL-assisted pharmacological therapy is a promising tool for optimizing topical treatments of KC and its precursor lesions. Future developments include AFL-assisted immune activation, changing drug administration route of systemic therapies, and utilizing drug chemo-combinations.