Peripheral natural killer cells and myeloid-derived suppressor cells correlate with anti-PD-1 responses in non-small cell lung cancer

Inhibition of immune checkpoint proteins like programmed death 1 (PD-1) is a promising therapeutic approach for several cancers, including non-small cell lung cancer (NSCLC). Although PD-1 ligand (PD-L1) expression is used to predict anti-PD-1 therapy responses in NSCLC, its accuracy is relatively less. Therefore, we sought to identify a more accurate predictive blood biomarker for evaluating anti-PD-1 response. We evaluated the frequencies of T cells, B cells, natural killer (NK) cells, polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), mononuclear myeloid-derived suppressor cells (M-MDSCs), and Lox-1+ PMN-MDSCs in peripheral blood samples of 62 NSCLC patients before and after nivolumab treatment. Correlation of immune-cell population frequencies with treatment response, progression-free survival, and overall survival was also determined. After the first treatment, the median NK cell percentage was significantly higher in responders than in non-responders, while the median Lox-1+ PMN-MDSC percentage showed the opposite trend. NK cell frequencies significantly increased in responders but not in non-responders. NK cell frequency inversely correlated with that of Lox-1+ PMN-MDSCs after the first treatment cycle. The NK cell-to-Lox-1+ PMN-MDSC ratio (NMR) was significantly higher in responders than in non-responders. Patients with NMRs ≥ 5.75 after the first cycle had significantly higher objective response rates and longer progression-free and overall survival than those with NMRs <5.75. NMR shows promise as an early predictor of response to further anti-PD-1 therapy.

Expansion of Myeloid-Derived Suppressor Cells Correlates with Renal Progression in Type 2 Diabetic Nephropathy

Type 2 diabetic nephropathy (T2DN) progresses with an increasingly inflammatory milieu, wherein various immune cells are relevant. Herein, we investigated the levels of myeloid-derived suppressor cells (MDSCs) and their clinical implication in patients with T2DN. A total of 91 subjects (T2DN, n=80; healthy, n=11) were recruited and their PBMCs were used for flow cytometric analysis of polymorphonuclear (PMN-) and monocytic (M-) MDSCs, in addition to other immune cell subsets. The risk of renal progression was evaluated according to the quartiles of MDSC levels using the Cox model. The proportion of MDSCs in T2DN patients was higher than in healthy individuals (median, 6.7% vs. 2.5%). PMN-MDSCs accounted for 96% of MDSCs, and 78% of PMN-MDSCs expressed Lox-1. The expansion of PMN-MDSCs was not related to the stage of T2DN or other kidney disease parameters such as glomerular filtration rate and proteinuria. The production of ROS in PMN-MDSCs of patients was higher than in neutrophils of patients or in immune cells of healthy individuals, and this production was augmented under hyperglycemic conditions. The 4th quartile group of PMN-MDSCs had a higher risk of renal progression than the 1st quartile group, irrespective of adjusting for multiple clinical and laboratory variables. In conclusion, PMN-MDSCs are expanded in patients with T2DN, and may represent as an immunological biomarker of renal progression.

Antitumor effects of MutT homolog 1 inhibitors in human bladder cancer cells

As standard second-line regimen has not been established for patients who are refractory to or relapse with cisplatin-based chemotherapy, an effective class of novel chemotherapeutic agents is needed for cisplatin-resistant bladder cancer. Recent publications reported that MutT homolog 1 (MTH1) inhibitors suppress tumor growth and induce impressive therapeutic responses in a variety of human cancer cells. Few studies investigated the cytotoxic effects of MTH1 inhibitors in human bladder cancer. Accordingly, we investigated the antitumor effects and the possible molecular mechanisms of MTH1 inhibitors in cisplatin-sensitive (T24) and – resistant (T24R2) human bladder cancer cell lines. These results suggest that TH588 or TH287 may induce cancer cell suppression by off-target effects such as alterations in the expression of apoptosis- and cell cycle-related proteins rather than MTH1 inhibition in cisplatin-sensitive and – resistant bladder cancer cells.

Abbreviations: MTH: MutT homolog; ROS: reactive oxygen species; CCK-8: cell counting kit-8; DCFH-DA: dichlorofluorescein diacetate; PARP: poly (ADP-ribose) polymerase

Role of myeloid-derived suppressor cells in immune checkpoint inhibitor therapy in cancer

Over the past decade, immune checkpoint inhibitor (ICI) therapy has demonstrated improved therapeutic efficacy in a wide range of cancers. However, the benefits are restricted to a small population of patients. Therefore, studies on understanding the mechanisms resistant to ICI therapy and for finding predictive biomarkers for ICI therapy are being actively conducted. Recent studies have demonstrated that myeloid-derived suppressor cells (MDSC) inhibit ICI therapy by various mechanisms, and that the response to ICI therapy can be improved by blocking MDSC activity. Moreover, low level of MDSC in patients with cancer has been shown to be correlated with their good prognosis after ICI treatment, thereby suggesting MDSC as a predictive biomarker in this regard. This review focuses on the roles of MDSC in ICI therapy and their relevant applications.

Multikinase inhibitor motesanib enhances the antitumor effect of cisplatin in cisplatin‑resistant human bladder cancer cells via apoptosis and the PI3K/Akt pathway

Motesanib (AMG 706) is a small organic molecule that acts as a multi‑targeted tyrosine kinase inhibitor of VEGF, PDGF and stem cell factor receptor. It exhibits a potent antitumor effect in vitro and in vivo. To investigate the anticancer effect and possible mechanisms of motesanib in cisplatin‑resistant human bladder cancer cells (T24R2), T24R2 cells were treated with motesanib (50 µM) with or without cisplatin (2.5 µg/ml). Cell growth was assessed by the Cell Counting Kit‑8 and clonogenic assays. Cell cycle progression and apoptotic cell death were examined using flow cytometry. The expression levels of apoptosis‑ and survival‑related proteins were determined by western blot analysis. In combination with cisplatin, motesanib exhibited synergistic inhibition on T24R2 cell growth. Treatment using motesanib in combination with cisplatin markedly induced apoptosis and promoted cell cycle arrest in the S phase. It also increased the expression of apoptosis‑related genes including caspases, poly(ADP‑ribose) polymerase and cytochrome c, whereas it decreased the expression of survival‑related genes including p‑PI3K and p‑Akt. In conclusion, combination treatment with motesanib and cisplatin revealed a synergistically enhanced anticancer effect on cisplatin‑resistant human bladder cancer cells, accompanied with induced apoptosis and cell cycle arrest. Thus, the multikinase inhibitor motesanib could be developed as possible therapeutic agent for bladder cancer.

A Type I Interferon and IL-10 Induced by Orientia tsutsugamushi Infection Suppresses Antigen-Specific T Cells and Their Memory Responses

Despite the various roles of type I interferon (type I IFN) responses during bacterial infection, its specific effects in vivo have been poorly characterized in scrub typhus caused by Orientia tsutsugamushi infection. Here, we show that type I IFNs are primarily induced via intracellular nucleic acids sensors, including RIG-I/MAVS and cGAS/STING pathways, during O. tsutsugamushi invasion. However, type I IFN signaling did not significantly affect pathogenesis, mortality, or bacterial burden during primary infection in vivo, when assessed in a mice model lacking a receptor for type I IFNs (IFNAR KO). Rather, it significantly impaired the induction of antigen-specific T cells and reduced memory T cell responses. IFNAR KO mice that recovered from primary infection showed stronger antigen-specific T cell responses, especially Th1, and more efficiently controlled bacteremia during secondary infection than wild type mice. Enhanced IL-10 expression by macrophages in the presence of type I IFN signaling might play a significant role in the suppression of antigen-specific T cell responses as neutralization or knock-out (KO) of IL-10 increased T cell responses in vitro. Therefore, induction of the type I IFN/IL-10 axis by O. tsutsugamushi infection might play a significant role in the suppression of T cell responses and contribute to the short longevity of cell-mediated immunity, often observed in scrub typhus patients.

TIGIT and PD-1 dual checkpoint blockade enhances antitumor immunity and survival in GBM

The use of inhibitory checkpoint blockade in the management of glioblastoma has been studied in both preclinical and clinical settings. TIGIT is a novel checkpoint inhibitor recently discovered to play a role in cancer immunity. In this study, we sought to determine the effect of anti-PD-1 and anti-TIGIT combination therapy on survival in a murine glioblastoma (GBM) model, and to elucidate the underlying immune mechanisms. Using mice with intracranial GL261-luc⁺ tumors, we found that TIGIT expression was upregulated on CD8⁺ and regulatory T cells (Tregs) in the brain compared to draining cervical lymph nodes (CLN) and spleen. We then demonstrated that treatment using anti-PD-1 and anti-TIGIT dual therapy significantly improved survival compared to control and monotherapy groups. The therapeutic effect was correlated with both increased effector T cell function and downregulation of suppressive Tregs and tumor-infiltrating dendritic cells (TIDCs). Clinically, TIGIT expression on tumor-infiltrating lymphocytes was shown to be elevated in patient GBM samples, suggesting that the TIGIT pathway may be a valuable therapeutic target. Expression of the TIGIT ligand, PVR, further portended a poor survival outcome in patients with low-grade glioma. We conclude that anti-TIGIT is an effective treatment strategy against murine GBM when used in combination with anti-PD-1, improving overall survival via modifications of both the T cell and myeloid compartments. Given evidence of PVR expression on human GBM cells, TIGIT presents as a promising immune therapeutic target in the management of these patients.

The relationship between clinical characteristics including presence of exposed lesions and health-related quality of life (HRQoL) in patients with psoriasis: analysis from the nationwide epidemiologic study for psoriasis in Korea (EPI-PSODE study)

BACKGROUND

Psychological aspect and quality of life should be considered in treating patients with psoriasis.

OBJECTIVE

We sought to ascertain which clinical characteristics including presence of exposed lesions are associated with impairment of health-related quality of life (HRQoL) in patients with psoriasis.

METHODS

The EPI-PSODE study was a nationwide, multicenter, cross-sectional study conducted in Korea that included 1260 adult patients with psoriasis. In addition to clinical characteristics including presence of exposed lesions, data were collected using the Psoriatic Arthritis (PsA) Screening and Evaluation (PASE), Dermatology Life Quality Index (DLQI), MOS 36-Item Short-Form Health Survey (SF-36), Work Productivity and Activity Impairment Questionnaire Psoriasis (WPAI: PSO) and Medication Satisfaction Questionnaire (MSQ).

RESULTS

Patients with a DLQI score > 5 (n = 990) were younger, had an earlier onset of psoriasis, scored higher on the Psoriasis Area and Severity Index (PASI), had higher body surface area (BSA) and had higher PASE scores than patients with DLQI ≤ 5 (n = 266). The group of patients with exposed lesions (n = 871) were younger and male predominance, earlier onset of psoriasis, longer disease duration, higher PASI/BSA score and a higher proportion with drinking and smoking history each than the group of patients without exposed lesions (n = 389). Presence of exposed lesions negatively influenced DLQI, 36-Item Short-Form Health Survey (SF-36) (mental component), presenteeism, total work productivity impairment and total activity impairment in the WPAI: PSO. In multiple regression model, PASI score was the only variable which was significantly associated with all HRQoL measures. Presence of exposed lesions was a significant factor affecting DLQI and SF-36 (mental).

CONCLUSION

The presence of exposed lesions has a negative impact on quality of life, mental health and work productivity. Therefore, effective treatments are particularly needed for psoriasis patients with exposed lesions.

Analysis of the number of enlarged pores according to site, age, and sex

BACKGROUND

Increasing the number of enlarged pores causes cosmetic problems. The difference in the number of enlarged pores according to facial site, age, and sex is unclear.

OBJECTIVE

To analyze the distribution of the number of enlarged pores according to facial site, age, and sex.

METHODS AND MATERIALS

We analyzed the number of the enlarged pores and the percentage of wrinkles in the nose, forehead, and cheek from 434 polarized images. The measurement results were analyzed according to site, age, and sex. Relationship between enlarged pore counts and wrinkle severity was also analyzed. The study was conducted by using DermaVision,™ which can take cross-polarization, parallel polarization, and ultraviolet light images.

RESULTS

The enlarged pores of the nose and forehead were more prominent than in the cheeks. Pore counts were increased with age, and the increment was significant between the 30's and 40's. There was no significant difference by gender. Enlarged pore counts were related to wrinkle severity.

CONCLUSIONS

The number of enlarged pores differs depending on body site and increased with age. The enlarged pore counts correlate with wrinkle severity and the correlation varies depending on the body site.

Lectin-type oxidized LDL receptor-1 distinguishes population of human polymorphonuclear myeloid-derived suppressor cells in cancer patients

Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) are important regulators of immune responses in cancer and have been directly implicated in promotion of tumor progression. However, the heterogeneity of these cells and lack of distinct markers hampers the progress in understanding of the biology and clinical importance of these cells. Using partial enrichment of PMN-MDSC with gradient centrifugation we determined that low density PMN-MDSC and high density neutrophils from the same cancer patients had a distinct gene profile. Most prominent changes were observed in the expression of genes associated with endoplasmic reticulum (ER) stress. Surprisingly, low-density lipoprotein (LDL) was one of the most increased regulators and its receptor oxidized LDL receptor 1 OLR1 was one of the most overexpressed genes in PMN-MDSC. Lectin-type oxidized LDL receptor 1 (LOX-1) encoded by OLR1 was practically undetectable in neutrophils in peripheral blood of healthy donors, whereas 5-15% of total neutrophils in cancer patients and 15-50% of neutrophils in tumor tissues were LOX-1⁺. In contrast to their LOX-1^- counterparts, LOX-1⁺ neutrophils had gene signature, potent immune suppressive activity, up-regulation of ER stress, and other biochemical characteristics of PMN-MDSC. Moreover, induction of ER stress in neutrophils from healthy donors up-regulated LOX-1 expression and converted these cells to suppressive PMN-MDSC. Thus, we identified a specific marker of human PMN-MDSC associated with ER stress and lipid metabolism, which provides new insight to the biology and potential therapeutic targeting of these cells.

Interleukin-10 attenuates tumour growth by inhibiting interleukin-6/signal transducer and activator of transcription 3 signalling in myeloid-derived suppressor cells

Interleukin-10 (IL-10) is a well-characterized anti-inflammatory cytokine, but its role in anti-cancer immunity is controversial. After injection with TC-1 cancer cells, we observed more rapid tumour growth and significantly higher interleukin-6 (IL-6) production in IL-10 knockout (IL-10(-/-)) mice than wild-type (WT) mice. Blocking IL-6 with an anti-IL-6 receptor (IL-6R) monoclonal antibody (mAb) inhibited tumour growth and myeloid-derived suppressor cell (MDSC) generation, which were significantly increased in IL-10-deficient mice. MDSCs and tumour cells from IL-10(-/-) mice had increased phosphorylated signal transducer and activator of transcription 3 (p-STAT3) levels. Treatment with a STAT3 inhibitor, S3I, reduced tumour growth, inhibited MDSC expansion, reduced IL-6 in tumours, and relieved T cell suppression. The combination of anti-IL-6R mAb and S3I further inhibited tumour growth compared to S3I treatment alone. These results suggested that the inhibition of the IL-6/STAT3 signalling axis is a candidate anti-cancer strategy, especially under systemic inflammatory conditions with high IL-6.

Topographic measurement of skin color by narrow-band reflectance spectrophotometer and minimal erythema dose (MED) in Koreans

BACKGROUND/AIMS

Narrow-band reflectance spectrophotometer is one of the objective and quantitative devices for measuring the skin colors. There has been some controversy concerning the relationship between the objectively measured skin color and cutaneous responsiveness to ultraviolet radiation, including minimal erythema dose (MED). The aims of this study were to compare the color of Korean brown skin with that of Caucasians by objective measurement with the narrow-band reflectance spectrophotometer, and to determine whether the skin color has any correlation with MED in Koreans, and demonstrate differences in this correlation according to the anatomical sites.

METHODS

With narrow-band reflectance spectrometer, skin colors were measured at 17 body sites of 20 healthy Korean male volunteers after measuring MED for the same subjects.

RESULTS

The constitutional skin color, as measured by the melanin index of the nonexposed sites, showed a statistically significant correlation with MED values, whereas the facultative skin color did not. The Korean brown skin showed higher melanin index and lower erythema index compared with that of Caucasians.

CONCLUSIONS

We confirmed significant differences in the correlation between MED and melanin indices, depending on the anatomic sites. This suggests that selection from various sites, even among the nonexposed sites, is quite important and deserves further evaluation.

Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons

DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

Regulation of tumor metastasis by myeloid-derived suppressor cells

Accumulation of pathologically activated immature myeloid cells with potent immune-suppressive activity is one of the major immunological hallmarks of cancer. In recent years, it became clear that in addition to their immune-suppressive activity, myeloid-derived suppressor cells (MDSCs) influence tumor progression in a variety of ways. They are directly implicated in the promotion of tumor metastases by participating in the formation of premetastatic niches, promoting angiogenesis and tumor cell invasion. In this review, we discuss recent data describing various roles of MDSCs in the formation of tumor metastases.

Histone deacetylase 11: A novel epigenetic regulator of myeloid derived suppressor cell expansion and function

Myeloid-derived suppressor cells (MDSCs), a heterogeneous population of cells capable of suppressing anti-tumor T cell function in the tumor microenvironment, represent an imposing obstacle in the development of cancer immunotherapeutics. Thus, identifying elements essential to the development and perpetuation of these cells will undoubtedly improve our ability to circumvent their suppressive impact. HDAC11 has emerged as a key regulator of IL-10 gene expression in myeloid cells, suggesting that this may represent an important targetable axis through which to dampen MDSC formation. Using a murine transgenic reporter model system where eGFP expression is controlled by the HDAC11 promoter (Tg-HDAC11-eGFP), we provide evidence that HDAC11 appears to function as a negative regulator of MDSC expansion/function in vivo. MDSCs isolated from EL4 tumor-bearing Tg-HDAC11-eGFP display high expression of eGFP, indicative of HDAC11 transcriptional activation at steady state. In striking contrast, immature myeloid cells in tumor-bearing mice display a diminished eGFP expression, implying that the transition of IMC to MDSC's require a decrease in the expression of HDAC11, where we postulate that it acts as a gate-keeper of myeloid differentiation. Indeed, tumor-bearing HDAC11-knockout mice (HDAC11-KO) demonstrate a more suppressive MDSC population as compared to wild-type (WT) tumor-bearing control. Notably, the HDAC11-KO tumor-bearing mice exhibit enhanced tumor growth kinetics when compare to the WT control mice. Thus, through a better understanding of this previously unknown role of HDAC11 in MDSC expansion and function, rational development of targeted epigenetic modifiers may allow us to thwart a powerful barrier to efficacious immunotherapies.

ER stress response regulates the fate of myeloid-derived suppressor cells through TRAIL receptors mediated apoptosis (TUM4P.907)

We studied the fate of myeloid-derived suppressor cells (MDSC) in cancer. Unexpectedly, MDSC had lower viability and a shorter half-life than their control counterparts neutrophils and monocytes. This effect was due to increased apoptosis mediated by the changes in TRAIL receptors (TRAIL-R) expression. Targeting TRAIL-R did not affect myeloid cells from naïve mice, but dramatically reduced the presence of MDSC and improved the immune responses in tumor-bearing mice. Pro-inflammatory cytokines did not affect TRAIL-R expression. However, induction of ER stress recapitulated changes in TRAIL-R expression observed in tumor-bearing hosts. ER stress response was detected in MDSC isolated from cancer patients and tumor-bearing mice, but not in control neutrophils or monocytes. Block of ER stress abrogated changes in TRAIL-R. Thus, MDSC pathophysiology is linked to ER stress, which shortens their lifespan in the periphery and promotes their expansion in bone marrow. In conclusion, TRAIL-R can be considered for selective targeting of MDSC.

ER stress regulates myeloid-derived suppressor cell fate through TRAIL-R-mediated apoptosis

Myeloid-derived suppressor cells (MDSCs) dampen the immune response thorough inhibition of T cell activation and proliferation and often are expanded in pathological conditions. Here, we studied the fate of MDSCs in cancer. Unexpectedly, MDSCs had lower viability and a shorter half-life in tumor-bearing mice compared with neutrophils and monocytes. The reduction of MDSC viability was due to increased apoptosis, which was mediated by increased expression of TNF-related apoptosis-induced ligand receptors (TRAIL-Rs) in these cells. Targeting TRAIL-Rs in naive mice did not affect myeloid cell populations, but it dramatically reduced the presence of MDSCs and improved immune responses in tumor-bearing mice. Treatment of myeloid cells with proinflammatory cytokines did not affect TRAIL-R expression; however, induction of ER stress in myeloid cells recapitulated changes in TRAIL-R expression observed in tumor-bearing hosts. The ER stress response was detected in MDSCs isolated from cancer patients and tumor-bearing mice, but not in control neutrophils or monocytes, and blockade of ER stress abrogated tumor-associated changes in TRAIL-Rs. Together, these data indicate that MDSC pathophysiology is linked to ER stress, which shortens the lifespan of these cells in the periphery and promotes expansion in BM. Furthermore, TRAIL-Rs can be considered as potential targets for selectively inhibiting MDSCs.

Effects of notch signaling on regulation of myeloid cell differentiation in cancer

Functionally altered myeloid cells play an important role in immune suppression in cancer, in angiogenesis, and in tumor cells' invasion and metastases. Here, we report that inhibition of Notch signaling in hematopoietic progenitor cells (HPC), myeloid-derived suppressor cells (MDSC), and dendritic cells is directly involved in abnormal myeloid cell differentiation in cancer. Inhibition of Notch signaling was caused by the disruption of the interaction between Notch receptor and transcriptional repressor CSL, which is normally required for efficient transcription of target genes. This disruption was the result of serine phosphorylation of Notch. We demonstrated that increased activity of casein kinase 2 (CK2) observed in HPC and in MDSC could be responsible for the phosphorylation of Notch and downregulation of Notch signaling. Inhibition of CK2 by siRNA or by pharmacological inhibitor restored Notch signaling in myeloid cells and substantially improved their differentiation, both in vitro and in vivo. This study demonstrates a novel mechanism regulation of Notch signaling in cancer. This may suggest a new perspective for pharmacological regulation of differentiation of myeloid cells in cancer.

Reciprocal relationship between myeloid-derived suppressor cells and T cells

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of myeloid cells that play a major role in the regulation of immune responses in many pathological conditions. These cells have a common myeloid origin, relatively immature state, common genetic and biochemical profiles, and, most importantly, the ability to inhibit immune responses. Although initial studies of MDSCs were almost exclusively performed in tumor-bearing mice or cancer patients, in recent years, it became clear that MDSCs play a critical role in the regulation of different types of inflammation that are not directly associated with cancer. In this review we discuss the nature of the complex relationship between MDSCs and the different populations of CD4(+) T cells.

Abstract 1515: Epigenetic silencing of retinoblastoma gene regulates pathologic differentiation of myeloid cells in cancer

Myeloid-derived suppressor cells (MDSC) are one of the major factors negatively regulating immune responses in cancer and many other pathologic conditions. These cells consist of two distinct populations: monocytic MDSC (M-MDSC) and polymorphonuclear MDSC (PMN-MDSC). PMN-MDSC is the predominant group of MDSC accumulated in cancer. Under physiologic conditions, the normal counterpart of M-MDSC - Ly6ChiLy6G- inflammatory monocytes (Mon) differentiate in periphery tissues to macrophages (MΦ) and dendritic cells (DCs). In contrast, a large proportion of M-MDSC, in tumor-bearing mice, acquired phenotypic, morphological and functional features of PMN-MDSC. In human, CD14+HLA-DR-/low M-MDSC from patients with multiple myeloma also differentiated into CD66b+ PMN-MDSC. This effect was caused by soluble tumor-derived factors and mediated by transcriptional silencing of the retinoblastoma (Rb) gene. M-MDSC had an amount of Rb1 similar to that in mature myeloid cells (PMN, DCs) while Rb1 was barely detectable in PMN-MDSC. Lack of Rb1 in mice with conditional deletion of the gene promoted an expansion of splenic CD11b+Ly6G+Ly6Clo cells, similar to the phenotype of PMN-MDSC in tumor-bearing mice. Moreover, immunogeneic EG7 tumor grew much faster in Rb1-KO mice than in Rb1-WT littermates. Mon from Rb1-KO mice acquired significantly increased proportion of PMN after in vitro culture compared to Rb1-WT Mon. In contrast, the overexpression of Rb1 substantially reduced the proportion of PMN-MDSC differentiated from M-MDSC. Histone deacetylase 2 (HDAC-2) was directly involved in down-regulation of Rb1 expression. Inhibition of HDAC in MDSC resulted in the increase in their Rb1 expression, abrogated differentiation of M-MDSC to PMN-MDSC, and restored M-MDSC differentiation towards DCs and MΦ. These results suggest that down-regulation of Rb by epigenetic modification plays a major role in accumulation of MDSC in cancer by regulating PMN-MDSC differentiation from M-MDSC. HDAC may be considered as potential targets for therapeutic regulation of MDSC in cancer.

Citation Format: Je-In Youn, Vinit Kumar, Michelle Collazo, Dmitry I. Gabrilovich. Epigenetic silencing of retinoblastoma gene regulates pathologic differentiation of myeloid cells in cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1515. doi:10.1158/1538-7445.AM2013-1515

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Epigenetic silencing of retinoblastoma gene regulates pathologic differentiation of myeloid cells in cancer

Two major populations of myeloid-derived suppressor cells (MDSC), monocytic MDSC (M-MDSC) and polymorphonuclear MDSC (PMN-MDSC) regulate immune responses in cancer and other pathologic conditions. Under physiologic conditions, Ly6C^hiLy6G⁻ inflammatory monocytes, which are the normal counterpart of M-MDSC, differentiate into macrophages and dendritic cells (DCs). PMN-MDSC is the predominant group of MDSC that accumulates in cancer. Here we show that a large proportion of M-MDSC in tumor-bearing mice acquired phenotypic, morphological and functional features of PMN-MDSC. Acquisition of this phenotype, but not the functional attributes of PMN-MDSC, was mediated by transcriptional silencing of the retinoblastoma (Rb) gene through epigenetic modifications mediated by histone deacetylase 2 (HDAC-2). These data demonstrate novel mechanism regulation of myeloid cells in cancer.

Abstract 5399: S100A9 drives MDSC migration and contributes to tumor progression by inhibiting the immune response

S100A9 is a pro-inflammatory molecule, secreted by myeloid cells, which has been reported to recruit leukocytes to the sites of inflammation or tumors. We have previously found that up-regulation of S100A9 expression in myeloid progenitor cells in cancer resulted in inhibition of DC differentiation and promotion of expansion of myeloid-derived suppressor cells (MDSC). It remained unclear how S100A9 could regulate MDSC expansion and function. In this study we evaluated the effects of secreted (extracellular) vs intracellular S100A9 on MDSC. Recombinant S100A9 or S100A8 proteins separately or as heterodimers did not promote MDSC expansion from hematopoietic progenitor cells (HPC), or affect their suppressive activity. However, recombinant proteins had a strong chemotactic effect on MDSC. Interestingly, this effect on immature myeloid cells isolated from naïve tumor-free mice was substantially lower. To study intracellular activity of S100A9 we used S100A9 transgenic (Tg) and knockout (KO) mice. Mice were injected with several different weakly and strongly immunogeneic tumors. As expected Tg mice had increased expansion of MDSC and KO mice had substantially reduced number of these cells. Different levels of MDSC did not affect the growth of weakly immunogeneic tumors. In contrast, overexpression of S100A9 in mice lead to significantly accelerated growth of immunogenic tumors. Lack of S100A9 resulted in fast rejection of immunogeneic tumors. Our data indicate that extracellular and intracellular S100A9 had different signalling in myeloid cells and apparently affect different aspects of their function. S100A9 over-expression, in vivo, inhibits the immune response, most likely by promoting MDSC accumulation and/or suppressive activity. Our data suggest that targeting of S100A9 in cancer can be an attractive therapeutic option.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5399. doi:1538-7445.AM2012-5399

Abstract 5411: Rb1 controls the differentiation of myeloid-derived suppressor cells subsets

Myeloid derived suppressor cells (MDSC) consist of two distinct subsets, polymorphonuclear/granulocytic-MDSC (PMN-MDSC), and monocytic-MDSC (M-MDSC) that differ in morphology, phenotype and preferred suppression mechanisms. PMN-MDSC is the predominant subset of MDSC that accumulates in spleen, bone marrow, blood, and tumor tissues in various mouse tumor models. M-MDSC produced higher level of cytokines and chemokines including G-CSF, IL-1b, IL-6, TNF-a, MCP-1 and RANTES compared to PMN-MDSC. The current paradigm considers PMN-MDSC and M-MDSC to differentiate from different progenitors alongside different lineages (granulocytic and monocytic, respectively). M-MDSC differentiate into dendritic cells and macrophages, whereas PMN-MDSC are terminally differentiated cells. Our study demonstrated that in cancer M-MDSC represent highly proliferative population of cells that differentiate not only to DC and macrophages but also to PMN-MDSC. The retinoblastoma gene (Rb1), a central regulator of the cell cycle and cell differentiation, is known to be involved in monocytic and granulocytic lineage commitment. When examining Rb1 levels in freshly isolated cells, M-MDSC expressed high levels of Rb1 similar to those in dendritic cells, macrophages, and neutrophils isolated from naïve mice. In sharp contrast, PMN-MDSC had undetectable Rb1. Lack of Rb1 in mice with conditional deletion of the gene promoted an expansion of splenic CD11b+Ly6G+Ly6Clo cells, similar to the phenotype of PMN-MDSC in tumor-bearing mice. Lack of Rb1 in PMN-MDSC was caused by transcriptional repression of the gene. In culture with GM-CSF, Rb1 expression in M-MDSC remained the same while in PMN-MDSC it was increased over time to the level seen in control neutrophils. Inhibition of rb1 expression in PMN-MDSC correlated with the level of histone acetylation of rb1 promoter. Treatment of PMN-MDSC with inhibitors of histone deacetilases (HDAC) resulted in the increase in rb1 expression suggesting that it may be controlled by histone modification. HDAC inhibitors abrogated differentiation of M-MDSC to PMN-MDSC in the presence of tumor explants conditioned medium. These results suggest that down-regulation of Rb1 plays a major role in accumulation of MDSC in cancer by regulating PMN-MDSC differentiation from M-MDSC. HDAC may be considered as potential targets for therapeutic regulation of MDSC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5411. doi:1538-7445.AM2012-5411

Characterization of the nature of granulocytic myeloid-derived suppressor cells in tumor-bearing mice

MDSCs are a group of cells with potent immune-suppressive activity. These cells accumulate in many pathologic conditions and play a major role in the regulation of immune responses. The nature of MDSC remains highly debatable. In cancer, most MDSCs are represented by cells with granulocytic phenotype and morphology, G-MDSC. The relationship between G-MDSCs and Neu remains unclear. In this study, we have found that G-MDSCs, from tumor-bearing, and Neu, from tumor-free, mice share a common morphology and phenotype. However, in contrast to Neu, a substantial proportion of G-MDSCs expressed M-CSFR and a CD244 molecule. Neu had significantly higher phagocytic activity, expression of lysosomal proteins, and TNF-α than corresponding G-MDSCs, which had significantly higher activity of arginase, MPO, and ROS. In contrast to G-MDSC, neither rested nor mobilized Neu suppressed T cells. G-MDSC survived 2 days in culture in the presence of GM-CSF and within 24 h, became phenotypic and functionally similar to Neu. Tumor-associated G-MDSC shared most characteristics of splenic G-MDSC, rather then Neu. These data suggest that in cancer, despite morphological and phenotypic similarities, G-MDSCs are functionally distinct from Neu and are comprised of pathologically activated precursors of Neu.

Tumor-infiltrating myeloid cells induce tumor cell resistance to cytotoxic T cells in mice

Cancer immunotherapeutic approaches induce tumor-specific immune responses, in particular CTL responses, in many patients treated. However, such approaches are clinically beneficial to only a few patients. We set out to investigate one possible explanation for the failure of CTLs to eliminate tumors, specifically, the concept that this failure is not dependent on inhibition of T cell function. In a previous study, we found that in mice, myeloid-derived suppressor cells (MDSCs) are a source of the free radical peroxynitrite (PNT). Here, we show that pre-treatment of mouse and human tumor cells with PNT or with MDSCs inhibits binding of processed peptides to tumor cell-associated MHC, and as a result, tumor cells become resistant to antigen-specific CTLs. This effect was abrogated in MDSCs treated with a PNT inhibitor. In a mouse model of tumor-associated inflammation in which the antitumor effects of antigen-specific CTLs are eradicated by expression of IL-1β in the tumor cells, we determined that therapeutic failure was not caused by more profound suppression of CTLs by IL-1β-expressing tumors than tumors not expressing this proinflammatory cytokine. Rather, therapeutic failure was a result of the presence of PNT. Clinical relevance for these data was suggested by the observation that myeloid cells were the predominant source of PNT in human lung, pancreatic, and breast cancer samples. Our data therefore suggest what we believe to be a novel mechanism of MDSC-mediated tumor cell resistance to CTLs.

Cross-sectional study on the correlation of serum uric acid with disease severity in Korean patients with psoriasis

BACKGROUND

Hyperuricaemia is a common finding in patients with psoriasis. However, previous studies have reported inconsistent results about the association between serum uric acid concentration (SUAC) and psoriasis severity. Recent studies have also reported that SUAC is associated with metabolic dysregulation.

AIM

To assess any association between SUAC and clinical features of psoriasis, and to investigate the characteristics of patients with psoriasis with hyperuricaemia compared with similar patients with normouricaemia.

METHODS

Cross-sectional data from 198 Korean patients with psoriasis who visited our clinic were analysed. Association of SUAC with clinical features of psoriasis, body mass index (BMI) and various laboratory values was assessed in both genders separately.

RESULTS

The average uric acid concentration of patients with psoriasis was not significantly different from that of the healthy population, for both genders (P > 0.05). There was a positive correlation between SUAC and Psoriasis Area and Severity Index (PASI) and BMI in patients with psoriasis (P < 0.05). There was no association with age of disease onset, family history of psoriasis, or other laboratory values (P > 0.05), in either gender. Of the other factors of disease severity, the extent of body surface involvement was correlated with uric acid concentration (P < 0.05) although there was no significant relationship with activity of individual lesions (P > 0.05). Mean PASI and extent of psoriasis were increased in hyperuricaemic compared with normouricaemic patients (P < 0.05).

CONCLUSIONS

SUAC in patients with psoriasis is positively associated with PASI, extent of skin involvement and BMI for both genders independently.

Abstract 3648: S100A9 play a role in MDSC expansion and migration but not in their activation

S100A9 is a pro-inflammatory molecule, secreted by myeloid cells, which has been reported to recruit leukocytes to the sites of inflammation or tumors. Up-regulation of S100A9 expression in myeloid progenitor cells was implicated in inhibition of DC differentiation and promotion of expansion of myeloid-derived suppressor cells (MDSC). These cells have been well described as a major component used by the tumor to be protected from the immune system. In order to determine if extracellular and intracellular S100A9 has similar effects on myeloid cell differentiation and function, we evaluated the effect of recombinant S100A9. Our results demonstrated that in contrast to overexpression of S100A9 in hematopoietic progenitor cell (HPC), the treatment of HPC with recombinant S100A9 did not affect their differentiation to mature macrophages, or dendritic cells. The same treatment does not affect the suppressive activity of MDSC purified from naïve or tumor-bearing mice either. However, recombinant S100A9 had strong chemotactic effect on MDSC. Interestingly, its effect on immature myeloid cells isolated from naïve tumor-free mice was substantially lower. Recently, it has been suggested that MDSC need two different signals: one – required for their expansion and inhibited differentiation of mature myeloid cells and the other one – for activation. Our data suggest that S100A9 may mediate first signals but not the second one. Intracellular up-regulation of S100A9 promotes expansion of MDSC and contributes to block of their differentiation, whereas extracellular S100A9 via cell receptors induce MDSC migration. A better understanding of how MDSC migrate into the tumor and how S100A9 is involved in this process could lead to the generation of new treatment aiming to block the migration of MDSC inside the tumor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3648. doi:10.1158/1538-7445.AM2011-3648

Abstract 3646: The role of myeloid-derived suppressor cells in tumor development

Myeloid-derived suppressor cells (MDSC) play an important role in regulation of immune response in cancer. They also have been implicated into promotion of tumor metastases and angiogenesis. We asked what role if any these myeloid cells can play in tumor formation associated in inflammation. To address this question we used previously described S100A9 deficient and S100A9 transgenic mice. S100A9, also known as calgranulin B or myeloid related protein 14 (MRP14), is a member of the S100 family of Ca2+ binding proteins. Previous studies have established that up-regulation of this protein in hematopoietic progenitor cells results in inhibition of dendritic cell maturation and accumulation of MDSC. We tested the role of MDSC in skin tumor formation using TgAC transgenic mice. These mice have activated k-ras mutation in keratinocytes. Upon topical treatment with 12-O-tetradecanoyl phorbol-13-acetate (TPA) they develop skin papillomas. We generated double transgenic mice and demonstrated that in mice overexpressing S100A9 the frequency and number of papillomas increased dramatically comparing with wild-type TgAC mice. The formation of papillomas was also significantly accelerated. To confirm the critical role of myeloid cells in the observed effect we used bone marrow transfer from wild-type or S100A9 Tg mice into lethally irradiated TgAC mice. Transfer of S100A9 Tg bone marrow cells resulted in significantly more rapid and more extensive formation of papillomas in TPA treated mice than transfer of control bone marrow. To assess effect of TPA treatment on cell infiltrate into skin wild-type or S100A9Tg mice were treated with TPA for 3 weeks. Skin from S100A9Tg mice had significantly higher number of Gr-1+ myeloid cells and CD4+ T cells than skin from wild-type mice. No differences in F4/80 macrophages and CD11c+ dendritic cells were seen. To further evaluate the possible role of MDSC in tumor formation we treat control and S100A9 knockout (KO) mice with combination of carcinogen DMBA and TPA using accelerated skin carcinogenesis protocol. The absence of S100A9 substantially delayed the onset of papilloma and decreased the number of lesions as compared with wild-type mice. These results suggest that MDSC may play an important role in inflammation associated tumoregenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3646. doi:10.1158/1538-7445.AM2011-3646

The biology of myeloid-derived suppressor cells: the blessing and the curse of morphological and functional heterogeneity

Myeloid-derived suppressor cells (MDSC) play an important role in the cellular network regulating immune responses in cancer, chronic infectious diseases, autoimmunity, and in other pathological conditions. Morphological, phenotypic and functional heterogeneity is a hallmark of MDSC. This heterogeneity demonstrates the plasticity of this immune suppressive myeloid compartment, and shows how various tumors and infectious agents can have similar biological effects on myeloid cells despite the differences in the factors that they produce to influence the immune system; however, such a heterogeneity creates ambiguity in the definition of MDSC as well as confusion regarding the origin and fate of these cells. In this review, we will discuss recent findings that help to better clarify these issues and to determine the place of MDSC within the myeloid cell lineage.

HIF-1α regulates function and differentiation of myeloid-derived suppressor cells in the tumor microenvironment

Myeloid-derived suppressor cells (MDSCs) are a major component of the immune-suppressive network described in cancer and many other pathological conditions. We demonstrate that although MDSCs from peripheral lymphoid organs and the tumor site share similar phenotype and morphology, these cells display profound functional differences. MDSC from peripheral lymphoid organs suppressed antigen-specific CD8(+) T cells but failed to inhibit nonspecific T cell function. In sharp contrast, tumor MDSC suppressed both antigen-specific and nonspecific T cell activity. The tumor microenvironment caused rapid and dramatic up-regulation of arginase I and inducible nitric oxide synthase in MDSC, which was accompanied by down-regulation of nicotinamide adenine dinucleotide phosphate-oxidase and reactive oxygen species in these cells. In contrast to MDSC from the spleen, MDSC from the tumor site rapidly differentiated into macrophages. Exposure of spleen MDSC to hypoxia resulted in the conversion of these cells to nonspecific suppressors and their preferential differentiation to macrophages. Hypoxia-inducible factor (HIF) 1α was found to be primarily responsible for the observed effects of the tumor microenvironment on MDSC differentiation and function. Thus, hypoxia via HIF-1α dramatically alters the function of MDSC in the tumor microenvironment and redirects their differentiation toward tumor-associated macrophages, hence providing a mechanistic link between different myeloid suppressive cells in the tumor microenvironment.

Anti-inflammatory triterpenoid blocks immune suppressive function of MDSCs and improves immune response in cancer

PURPOSE

Myeloid-derived suppressor cells (MDSC) are one of the major factors responsible for immune suppression in cancer. Therefore, it would be important to identify effective therapeutic means to modulate these cells.

EXPERIMENTAL DESIGN

We evaluated the effect of the synthetic triterpenoid C-28 methyl ester of 2-cyano-3,12-dioxooleana-1,9,-dien-28-oic acid (CDDO-Me; bardoxolone methyl) in MC38 colon carcinoma, Lewis lung carcinoma, and EL-4 thymoma mouse tumor models, as well as blood samples from patients with renal cell cancer and soft tissue sarcoma. Samples were also analyzed from patients with pancreatic cancer treated with CDDO-Me in combination with gemcitabine.

RESULTS

CDDO-Me at concentrations of 25 to 100 nmol/L completely abrogated immune suppressive activity of MDSC in vitro. CDDO-Me reduced reactive oxygen species in MDSCs but did not affect their viability or the levels of nitric oxide and arginase. Treatment of tumor-bearing mice with CDDO-Me did not affect the proportion of MDSCs in the spleens but eliminated their suppressive activity. This effect was independent of antitumor activity. CDDO-Me treatment decreased tumor growth in mice. Experiments with severe combined immunodeficient-beige mice indicated that this effect was largely mediated by the immune system. CDDO-Me substantially enhanced the antitumor effect of a cancer vaccines. Treatment of pancreatic cancer patients with CDDO-Me did not affect the number of MDSCs in peripheral blood but significantly improved the immune response.

CONCLUSIONS

CDDO-Me abrogated the immune suppressive effect of MDSCs and improved immune responses in tumor-bearing mice and cancer patients. It may represent an attractive therapeutic option by enhancing the effect of cancer immunotherapy.

Notch and wingless signaling cooperate in regulation of dendritic cell differentiation

Dendritic cell (DC) differentiation is regulated by stroma via a network of soluble and cell-bound factors. Notch is one of the major elements of this network. Its role in DC differentiation, however, is controversial. Here, we demonstrate that activation of Notch signaling in hematopoietic progenitor cells (HPCs) promoted differentiation of conventional DCs via activation of the canonical Wingless (Wnt) pathway. Inhibition of the Wnt pathway abrogated the effect of Notch on DC differentiation. The fact that activation of the Wnt pathway in Notch-1-deficient embryonic stem cells restored DC differentiation indicates that Wnt signaling is downstream of the Notch pathway in regulating DC differentiation. Notch signaling activated the Wnt pathway in HPCs via expression of multiple members of the Frizzled family of Wnt receptors, which was directly regulated by the CSL (RPB-Jkappa) transcription factor. Thus, these data suggest a model of DC differentiation via cooperation between Wnt and Notch pathways.

Subsets of myeloid-derived suppressor cells in tumor-bearing mice

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of cells that play a critical role in tumor associated immune suppression. In an attempt to identify a specific subset of MDSC primarily responsible for immunosuppressive features of these cells, 10 different tumor models were investigated. All models showed variable but significant increase in the population of MDSC. Variability of MDSC expansion in vivo matched closely the effect of tumor cell condition medium in vitro. MDSC consists of two major subsets of Ly6G(+)Ly6C(low) granulocytic and Ly6G(-)Ly6C(high) monocytic cells. Granulocytic MDSC have increased level of reactive oxygen species and undetectable level of NO whereas monocytic MDSC had increased level of NO but undetectable levels of reactive oxygen species. However, their suppressive activity per cell basis was comparable. Almost all tumor models demonstrated a preferential expansion of granulocytic subset of MDSC. We performed a phenotypical and functional analysis of several surface molecules previously suggested to be involved in MDSC-mediated suppression of T cells: CD115, CD124, CD80, PD-L1, and PD-L2. Although substantial proportion of MDSC expressed those molecules no differences in the level of their expression or the proportion, positive cells were found between MDSC and cells from tumor-free mice that lack immune suppressive activity. The level of MDSC-mediated T cell suppression did not depend on the expression of these molecules. These data indicate that suppressive features of MDSC is caused not by expansion of a specific subset but more likely represent a functional state of these cells.

Differential regulation of antigen-specific CD8+ T cell responses by IL-12p40 in a dose-dependent manner

IL-12p40 is a natural antagonist which inhibits IL-12- and IL-23-mediated biological activity by blocking the binding of IL-12/23 to their receptors. Recently, IL-12p40 was also shown to have immune-enhancing activity through the activation of macrophages or dendritic cells. In this study, we investigated the effects of IL-12p40 as a genetic adjuvant on immune modulation using recombinant adenoviruses expressing IL-12p40 (rAd/IL-12p40) and OVA (rAd/OVA). Coimmunization of rAd/IL-12p40 at a low dose (1 x 10(4) PFU) with rAd/OVA resulted in OVA-specific immune enhancement, while a high dose of rAd/IL-12p40 (1 x 10(8) PFU) caused significant suppression of CD8(+) T cell responses. In addition, the enhancement and suppression of OVA-specific CD8(+) T cell responses correlated with antitumor activity against E.G7-OVA tumor challenge, which subsequently affected the survival rate. Moreover, the differential CD8(+) T cell response by IL-12p40 was still observed in IL-12Rbeta2 knockout (IL-12Rbeta2KO), but not in IL-12Rbeta1 knockout (IL-12Rbeta1KO) mice, indicating that IL-12p40 is a cytokine which can modulate Ag-specific T cell responses depending on IL-12Rbeta1. Our findings provide a novel insight on the physiological role of IL-12p40, which can be informative in the design of vaccine strategies and therapeutic regimens.

The difference between the constitutive and facultative skin color does not reflect skin phototype in Asian skin

BACKGROUND/PURPOSE

The assessment of the sensitivity of human skin to ultraviolet (UV) radiation is important in the area of phototherapy, photodermatoses, photo-aging, photo-carcinogenesis, and photo-protection. Some reports have shown that quantitatively measured skin color is a good indicator for predicting UV sensitivity to human skin in Caucasians. In this study, our aim was to define the correlation between skin color and the skin phototype assessed by the Fitzpatrick method in Asian brown skin.

METHODS

A total of 180 medical students with similar life styles were included in this study. Their skin phototype was classified according to the system introduced by Fitzpatrick. Then, using a Minolta Spectrophotometer CM-2002, their skin color was determined on the buttocks and forehead. The buttock color was taken as the constitutive skin color, and the forehead color as the facultative skin color. Using these measured values, we compared the skin color with the skin phototype to find their correlation. Also, we investigated whether the difference between the constitutive and facultative skin colors of each individual had a relationship with his or her skin phototype.

RESULTS

The constitutive skin color became darker with increasing skin phototype, and this change was statistically significant. As for the facultative skin color, it also became darker with increasing skin phototype, but was less well correlated with the skin phototype than the constitutive skin color. However, the difference between the constitutive and facultative skin colors did not show consistent results in predicting the skin phototype.

CONCLUSION

In this study, we found that the constitutive skin color can be a good indicator of the skin phototype. However, the difference between the constitutive and facultative skin colors of each individual does not give any meaningful information for the assessment of his or her skin phototype in Asian skin.

Electrical measurement of moisturizing effect on skin hydration and barrier function in psoriasis patients

Transepidermal water loss (TEWL) in psoriatic skin lesions seems to be related to the severity of the psoriasis, and the electrical capacitance and conductance of the skin are indicators of the hydration level of the stratum corneum. We compared the characteristics of these electrical measurements, in assessing the persistent effect of a moisturizing cream on skin hydration and barrier function in psoriasis patients. Seventeen Korean psoriasis patients were recruited. Their right leg was treated with the moisturizer twice daily for 6 weeks, while their left leg was used as the control site. For each patient, one psoriatic plaque on each leg was selected as the involved psoriatic lesion. Uninvolved psoriatic skin was regarded as the apparently healthy looking skin 4-5 cm away from the periphery of the psoriatic lesion. The TEWL, electrical capacitance and conductance were measured, in order to evaluate the barrier function and hydration level of the stratum corneum. The clinical and biophysical data for each patient were recorded at the start of the study and after 2, 4 and 6 weeks. The degree of skin dryness at the applied area improved progressively. The electrical capacitance at the treated psoriatic lesion increased significantly after 2 weeks, and this improvement was maintained during the entire study period. However, no noticeable change was observed in the electrical conductance. The TEWL showed an inverse pattern to that of the skin capacitance, decreasing during the study period. The skin capacitance and TEWL exhibited good correlation with the visual assessment of skin dryness, but the skin conductance did not. Our data suggest that electrical capacitance and TEWL may be useful in the evaluation of the effect of a moisturizer on the hydration status and barrier function of psoriatic skin.

Enhancement of Interleukin-12 Gene-Based Tumor Immunotherapy by the Reduced Secretion of p40 Subunit and the Combination with Farnesyltransferase Inhibitor

Interleukin-12 (IL-12) gene was shown to produce both IL-12 and p40 subunit. The excess production of the p40 subunit as a natural antagonist of IL-12 is a major obstacle of IL-12 gene-based cancer therapy. We previously reported that IL-12N220L gene, which selectively reduces the secretion of the p40 subunit, induces long-lasting stronger type 1 helper T cells (T(H)1) and cytotoxic T lymphocyte (CTL) immunity in hepatitis C virus (HCV) E2 DNA vaccination model and higher protection from challenge with tumor cells expressing E2 than IL-12 in a prophylactic setting. Here, we demonstrated that intratumoral injection of IL-12N220L-expressing adenovirus showed better tumor growth inhibition and higher survival rate than that of IL-12 or granulocyte macrophage-colony stimulating factor (GM-CSF)-expressing adenovirus in a therapeutic setting. In particular, the mice cured by IL-12N220L treatment were protected against intravenous rechallenge of the same tumor cells better than those by IL-12 treatment. In addition, the enhanced antitumor activity of IL-12N220L was confirmed in B16F10 lung metastasis model, which correlated with the frequency of tumor-specific interferon (IFN)-gamma-secreting cells. When tested in CT26/NP tumor that expresses influenza nucleoprotein (NP) as a tumor antigen, IL-12N220L induced stronger NP-specific T(H)1 and CTL responses than IL-12, particularly at a later time point, indicating the generating long-term tumor-specific memory T-cell responses. Moreover, the potent antitumor effects of IL-12N220L were further augmented by combination with chemotherapy using farnesyltransferase inhibitor (FTI), LB42908. Taken together, our results suggest that IL-12N220L is superior to IL-12 in cancer immunotherapy, which can be further enhanced by combination with chemotherapy.

Evaluation of skin surface hydration in Korean psoriasis patients: a possible factor influencing psoriasis

Psoriasis is recognized as a chronic, relapsing disorder of the skin, and its clinical course is influenced by various environmental factors. However, only a few articles have addressed the effect of low epidermal hydration status as an exacerbating factor of psoriasis. Our study was performed to investigate the relationship between subjective assessment and quantified data regarding dryness parameters in psoriasis patients. Seventy psoriasis patients were enrolled in our study. Subjective assessments were undertaken by evaluating the extent of involvement, erythema, scale and infiltration of individual lesions. Functional status of stratum corneum was evaluated by measuring electrical capacitance and conductance of the lesional and uninvolved skin of psoriatic patients. In addition, measurement of trans-epidermal water loss was performed. The results showed poor hydration status and barrier function in involved psoriatic epidermis compared with the uninvolved skin. Subjective assessment showed fairly good correlation with the quantified values. In conclusion, the degree of dryness in psoriatic skin lesions--which we presume to be one of the aggravating factors of psoriasis--seemed to be related to disease severity.

Effects of 12-O-tetradecanoyl-phorbol-13-acetate [corrected] and sodium lauryl sulfate on the production and expression of cytokines and proto-oncogenes in photoaged and intrinsically aged human keratinocytes

Skin aging may be divided into photoaging and intrinsic aging. The purpose of this study was to investigate the effects of 12-O-tetradecanoyl-phorbol-13-acetate and sodium lauryl sulfate on the production and expression of cytokines and proto-oncogenes in photoaged and intrinsically aged skin, compared with young skin. Keratinocytes were taken from newborns, young adults in their twenties, and from the forearm and thigh of volunteers in their fifties and seventies. Interleukin-1alpha and -6, and interleukin-1 receptor antagonist, c-fos and c-myc were measured after cultured keratinocytes had been treated with 12-O-tetradecanoyl-phorbol-13-acetate and sodium lauryl sulfate. There has been no report concerning the dependence of cytokine production by sodium lauryl sulfate upon photoaging and intrinsic aging. This study also involves the first investigation of the effects of aging on c-myc expression by 12-O-tetradecanoyl-phorbol-13-acetate treatment. Cytokine production decreased markedly with age. These results suggest the progressive decline of cellular function with age. The ratio of cytokine production in the irritant-treated group compared with that in the control group showed a different pattern in photoaging and intrinsic aging. With the significant difference between photoaging and intrinsic aging, T/C ratio decreased in interleukin-1alpha and interleukin-1 receptor antagonist upon aging, whereas it increased in interleukin-6. S/C ratio was uniquely elevated on photoaged skin in the 50 y age group. It is suggested that photoaged skin shows an exaggerated reaction to surfactant. Compared with the control, c-fos expression in 12-O-tetradecanoyl-phorbol-13-acetate-treated keratinocytes decreased with age in the thigh, but increased in the photoaged skin of forearm. The increased c-fos expression in 12-O-tetradecanoyl-phorbol-13-acetate-treated keratinocytes could be relevant for the predisposition of photoaged keratinocytes to malignant transformation.

Suppression of UVB-induced cutaneous erythema by a previous UVB exposure

People who vacation in sunny places are exposed to the sun on multiple occasions at least on a daily basis. The clinical assessment of sun exposure is erythema in the first 48 h after exposure and pigmentation at times greater than 3-5 days. The purpose of this investigations was to determine the extent to which consecutive erythemogenic exposures result in additive erythema responses. Studies were conducted in which volunteers were first exposed to a graded series of fluences of UVB radiation and then on subsequent days (1-3 days) the same sites along with the surrounding unexposed skin were challenged with varying fluences of UVB radiation. The erythema reactions were assessed clinically and were objectively documented with diffuse reflectance spectroscopy. The sites that received two exposures always showed a reduced erythema response compared to a single erythemogenic exposure. The suppression of erythema was more pronounced when the second exposure was given 48 h after the first. The erythema suppression was maximal when the first exposure was at 1.3 minimum erythema dose (MED). The pigment response to the first exposure was completely suppressed for fluences less than 1.5 MED. We thus provide evidence for a decoupling of the classical sequence of erythema-pigmentation response. We also show that the erythema induced by a second exposure may be substantially suppressed by an earlier exposure, and that this cannot be due to melanin photoprotection or due to substantial thickening of the stratum corneum. We propose that the cause may be some diffusible element of yet unknown origin.

Changes of skin blood flow and color on lesional and control sites during PUVA therapy for psoriasis

BACKGROUND

Although the colors of psoriatic lesions, largely determined by erythema and scales, are important clinical indicators, expressing them in an objective manner is difficult. Cutaneous blood flow (CBF) also affects erythema. Serial measurement of these parameters during phototherapy was almost nonexistent.

OBJECTIVE

The objectives of our study were to observe the changes of color parameters and the CBF of psoriatic lesions during PUVA therapy and to determine their clinical significance.

METHODS

CBF, measured by laser Doppler flowmetry, and color parameters, measured by tristimulus colorimetry and reflectance spectrophotometry, were assessed in 13 patients with psoriasis who received PUVA therapy.

RESULTS

The values of CBF, erythema index (EI), and a(*) (color parameter representing red-green axis) in psoriatic lesions were significantly different from those observed in the control sites before therapy. The parameters of psoriatic lesions normalized according to the clinical improvement and approached those of the control sites as PUVA therapy progressed. The values of melanin index (MI), L(*) (color parameter representing white-black axis), and b(*) (color parameter representing yellow-blue axis) showed no significant difference between the psoriatic plaques and the control sites. They all displayed changes toward darkening and indicated tanning induced by PUVA therapy. Serial changes presented a generally unidirectional pattern in the control sites. However, this was not always the case in psoriatic lesions because scale, infiltration, and erythema also affected the measurement of blood flow and the color of the skin.

CONCLUSION

Color parameters and CBF were closely related with clinical improvement according to consecutive phototherapy. They may serve as objective indices for the visible morphology and underlying lesional pathophysiology of psoriasis.

Non-contact measurement of thermal diffusivity in tissue

We demonstrate the application of an infrared (IR) imaging technique for non-contact determination of thermal diffusivity in biological materials. The proposed method utilizes pulsed laser excitation to produce an initial three-dimensional temperature distribution in tissue, and records IR images of subsequent heat diffusion. The theoretical model assumes that the time-dependent temperature increase following pulsed laser exposure is due to independent heat diffusion in longitudinal and lateral directions. A nonlinear least-squares algorithm is used to compute the lateral thermal point spread function from a pair of recorded IR images and to determine the thermal diffusivity of a test specimen. The recorded time-sequence of IR images is used to compute thermal diffusivity as a function of increasing time interval between two IR emission images. Experimental application of the method was demonstrated using tissue phantoms, ex vivo samples of hydrated cartilage and in vivo epidermis.

MICA 5.1 allele is a susceptibility marker for psoriasis in the Korean population

In order to investigate the possibility that the MICA gene is involved in the pathogenesis of psoriasis, microsatellite polymorphism in the transmembrane region of MICA was studied in 138 Korean patients with psoriasis and compared with 126 healthy controls. The MICA 5.1 microsatellite allele, consisting of 5.1 repetitions of GCT/AGC, showed significantly higher frequencies in all patients and in patients with type I psoriasis than in the controls. HLA-A30-B13-Cw*0602-MICA 5.1 and A1-B37-Cw*0602-MICA 5.1 were found to be an extended haplotype associated with psoriasis. Our results suggest that the MICA 5.1 allele might be a genetic marker related to the early onset of psoriasis and play a secondary role to the HLA-Cw*0602 gene or an unknown causative gene closely linked to HLA-Cw*0602 in the genetic susceptibility to psoriasis.

Optical and thermal properties of nasal septal cartilage

BACKGROUNDS AND OBJECTIVES

The aim of the study was to measure the spectral dependence of optical absorption and reduced scattering coefficients and thermal conductivity and diffusivity of porcine nasal septal cartilage. Values of optical and thermal properties determined in this study may aid in determining laser dosimetry and allow selection of an optical source wavelength for noninvasive diagnostics for laser-assisted reshaping of cartilage.

MATERIALS AND METHODS

The diffuse reflectance and transmittance of ex vivo porcine nasal septal cartilage were measured in the 400- to 1,400-nm spectral range by using a spectrophotometer. The reflectance and transmittance data were analyzed by using an inverse adding-doubling algorithm to obtain the absorption (mu(a)) and reduced scattering (mu(a)') coefficients. A multichannel thermal probe controller system and infrared imaging radiometer methods were applied to measure the thermal properties of cartilage. The multichannel thermal probe controller system was used as an invasive technique to measure thermal conductivity and diffusivity of cartilage at three temperatures (27, 37, 50 degrees C). An infrared imaging radiometer was used as a noninvasive method to measure the thermal diffusivity of cartilage by using a CO(2) laser source (lambda = 10.6 microm) and an infrared focal plane array (IR-FPA) camera.

RESULTS

The optical absorption peaks at 980 nm and 1,180 nm in cartilage were observed and corresponded to known absorption bands of water. The determined reduced scattering coefficient gradually decreased at longer wavelengths. The thermal conductivity values of cartilage measured by using an invasive probe at 27, 37, and 50 degrees C were 4.78, 5.18, and 5.76 mW/cm degrees C, respectively. The corresponding thermal diffusivity values were 1.28, 1.31, and 1.40x 10(-3) cm(2)/sec. Because no statistically significant difference in thermal diffusivity values with increasing temperature is found, the average thermal diffusivity is 1.32 x 10(-3) cm(2)/sec. The numerical estimate for thermal diffusivity obtained from infrared radiometry measurements was 1.38 x 10(-3) cm(2)/sec.

CONCLUSION

Values of the spectral dependence of the optical absorption and reduced scattering coefficients, and thermal conductivity and diffusivity of cartilage were measured. The invasive and noninvasive diffusivity measurements were consistent and concluded that the infrared imaging radiometric technique has an advantage to determine thermal properties, because damage to the cartilage sample may be avoided. The measured values of absorption and reduced scattering coefficients can be used for predicting the optical fluence distribution in cartilage and determining optical source wavelengths for the laser-assisted cartilage reshaping studies. The thermal conductivity and diffusivity values can play role in understanding thermal-dependent phenomenon in cartilage during laser irradiation and determining laser dosimetry for the laser-assisted cartilage reshaping studies.

Comparative quantitative analysis of ultraviolet B-induced skin blood flow change using laser Doppler perfusion imaging technique

Laser Doppler perfusion imaging (LDI), recently developed, can generate a color-coded image of tissue perfusion, making it possible to assess the spatial distribution of skin perfusion without touching the surface. Using this apparatus, we investigated ultraviolet B (UVB)-induced perfusion profile of the skin and compared the results with those obtained from laser Doppler flowmetry (LDF). Fifteen adult male Korean volunteers were irradiated with several doses of UVB ranging from 25 mJ/cm2 to 186 mJ/cm2. Twenty-four hours later, the erythema reaction was evaluated with LDF and LDI systems. There was a significant correlation between the logarithmic dose of UVB and erythema values. The curves consisted of two parts, an initial, flat phase and then a linear, steep one. Also, there was a good correlation between LDF and LDI. The LDI is as sensitive as conventional LDF, but has the many advantages of measuring blood flow over large areas without contact with the skin surface. This instrument will be useful in the measurement of skin blood flow in many areas of dermatological application.