Jae-Bok Park

Therapeutic Synergy of Human Papillomavirus E7 Subunit Vaccines plus Cisplatin in an Animal Tumor Model: Causal Involvement of Increased Sensitivity of Cisplatin-Treated Tumors to CTL-Mediated Killing in Therapeutic Synergy

Purpose: The goal of this study was to investigate the therapeutic potentials of combining chemotherapy with human papillomavirus (HPV) E7 subunit vaccines in an animal tumor model and to determine the underlying therapeutic mechanisms. Experimental Design: Animals bearing HPV E6/E7–expressing tumors were treated intratumorally with a selected cytotoxic drug, cisplatin, twice at 1-week interval and s.c. with E7 subunit vaccines thrice at 1-week interval. Tumor chemoimmunoresponse was measured by tumor size. Ag-specific CTL activities and tumor histology were checked in mice under treatments. Apoptosis, in vivo T-cell subset depletion, adoptive CTL transfer, and tumor regression were used to determine the mechanisms for antitumor therapeutic effects. Results: Combined therapy using cisplatin plus E7 subunit vaccines improved cure and recurrence rates of tumors and long-term antitumor immunity dramatically more than single therapy alone. In particular, both components of E7 subunit vaccines were required for induction of Ag-specific CTL as well as therapeutic synergy when combined with cisplatin. This therapeutic synergy was abrogated by depletion of CD8+ T cells in vivo and was concomitant with histologic changes (such as heavy infiltration of lymphocytes and reduced tumor cell density). Finally, the increased sensitivity of cisplatin-treated tumors to CTL-mediated killing was found to be responsible for therapeutic synergy. Conclusions: E7 subunit vaccines plus cisplatin mediate antitumor therapeutic synergy through the increased sensitivity of cisplatin-treated tumors to CTL-mediated killing. Moreover, E7-based therapeutic vaccines have the potential to improve chemotherapy in patients with cervical cancer.

CpG-ODN-stimulated dendritic cells act as a potent adjuvant for E7 protein delivery to induce antigen-specific antitumour immunity in a HPV 16 E7-associated animal tumour model.

We previously reported that both E7 and CpG‐oligodeoxynucleotide (ODN) are required for protecting animals from human papillomavirus (HPV) 16 E7‐associated tumour challenge. Here we investigate dendritic cells (DC)‐based approach in this protection. In the study, we isolated bone marrow‐derived DC and stimulated DC with E7 and ODN. In vitro stimulation of DC with E7 plus ODN resulted in more production of interleukin‐12, as compared to that with E7 or ODN alone. Further injection with E7+ODN‐stimulated DC resulted in more significant tumour protection, as compared to stimulation with E7 or ODN alone. We further evaluated the levels of immune responses induced by DC stimulated with E7+ODN. We observed little enhancement of E7‐specific antibody and T helper cell proliferative responses by E7+ODN stimulation, as compared to E7 stimulation. However, there was some enhancement of interferon‐γ (IFN‐γ) production from CD4+ T cells and a more significant production of IFN‐γ from CD8+ T cells by E7+ODN stimulation, as compared to E7 stimulation alone. This was consistent with intracellular IFN‐γ staining levels of CD8+ T cells. Tumour protection further appeared to be mediated by CD8+ T cells, as determined by in vivo T‐cell depletion. Thus, these data suggest that upon ODN stimulation DC might function as a potent adjuvant for E7 protein delivery for induction of protective cellular immunity against HPV E7‐associated tumour challenge.

Antifibrotic effect through the regulation of transcription factor using ring type-Sp1 decoy oligodeoxynucleotide in carbon tetrachloride-induced liver fibrosis.

Liver fibrosis is characterized by the excessive accumulation of extracellular matrix (ECM). Recent advances in the knowledge about the cellular, molecular and genetic aspects of fibrosis have opened a new era of research on liver cirrhosis. A transcription factor, Sp1, originally described as a ubiquitous transcription factor, is involved in the basal expression of ECM genes and may be important in the fibrotic processes.

Suppressive effects of bee venom on the immune responses in collagen-induced arthritis in rats

The effect of bee venom (BVA) on the development of type II collagen (CII)-induced arthritis (CIA) in rats has been studied. Male rats were immunized with an emulsion of 200 microg of CII and complete Freunds adjuvant (CFA). The rats were then given intraperitoneally (i.p.) injection of a suspension of BVA or saline during the experiment. The effect of BVA on cellular responses to CII was examined. In the control rats, the onset of arthritis was observed at the 24th day after the CII-immunization, and the severity of CIA was developed gradually. As compared with rats treated with saline, BVA i.p. injected at doses of more than 20 microl/100g mouse once a day for 14 days inhibited the ability of inguinal lymph node cells to produce T cell cytokines interleukin-1beta, -2, -6, tumor necrosis factor-alpha and interferon-gamma when the cells were obtained from rats 24 days after immunization and cultured in vitro with CII. When rats were injected i.p. with sheep red blood cells, hemagglutination titers in BVA-treated and control rats did not differ significantly when low doses of BVA was given to rats. However, i.p. injection of BVA at doses of more than 10 microl/100g/day suppressed antibody production. Pretreatment of rats with BVA could inhibit the development of collagen arthritis even when 10-20 microl/100g/day of the BVA were used for pretreatment. Interestingly, higher doses than 10 microlBVA/100g mouse were much effective for arthritis incidence. Treatment of rats with BVA prevented the development of collagen arthritis in a dose-dependent manner. Doses of BVA (15 and 20 microl/100g) resulted in decreased incidence of arthritis. In conclusion, therapeutic i.p injection with BVA improved the clinical course of the disease and the immune response to CII.

Antitumor Therapeutic and Antimetastatic Activity of Electroporation-Delivered Human Papillomavirus 16 E7 DNA Vaccines: A Possible Mechanism for Enhanced Tumor Control

DNA vaccines are known to be lacking in immunogenicity in humans. Presently, electroporation (EP) is thought to overcome this limitation. Here, we investigate whether human papillomavirus 16 E7 DNA vaccines delivered by EP might elicit potent antitumor activity in animal cervical cancer models, with a focus on the underlying mechanism(s). Intramuscular (IM)-EP delivery of E7 DNA vaccines induced more potent antitumor therapeutic and antimetastatic activity compared with IM delivery. Moreover, the tumor-controlled animals by IM-EP possessed long-term memory responses to parental tumor cells. This improved antitumor effect was concomitant with augmented Ag-specific CTL activities. IM-EP also induced IgG and Th-cell responses higher than IM delivery. Finally, IM-EP resulted in more antigen production in and more attraction of immune cells into the site of DNA injection, suggesting that these biological and immunological changes made by IM-EP might be responsible for enhanced CTL activities and antitumor resistance. Thus, this study shows that IM-EP can induce more potent antitumor activity by augmenting CTL responses possibly through more antigen production in and more attraction of immune cells into the muscle sites. This study also suggests that IM-EP of E7 DNA vaccines might be a potential approach toward treating patients with cervical cancer.

Aberrant p16INK4A RNA transcripts expressed in hepatocellular carcinoma cell lines regulate pRb phosphorylation by binding with CDK4, resulting in delayed cell cycle progression

Abstract: The inactivation of the p16INK4A (p16) gene by promoter hypermethylation has been reported in many human cancers. We previously reported that aberrant p16 RNA transcripts are expressed in hepatocellular carcinoma (HCC) cell lines having hypermethylated p16 promoters. In this study, we investigated the functional roles of aberrant p16 RNA transcripts in HCC cells to elucidate molecular events underlying hepatocarcinogenesis. The aberrant p16 RNA transcripts encoded key peptides (amino acids 84–103) involved in binding with cyclin‐dependent kinase (CDK) 4. GST‐aberrant p16 fusion proteins were found to interact with endogenous CDK4 in vitro. Furthermore, overexpression of these aberrant p16 RNA transcripts resulted in decreased cell proliferation rate, enlargement of cell shape and reduced level of hyperphosphorylated forms of pRb. Overall, our results suggest that the aberrant p16 RNA transcripts have functions similar to those of wild type p16 in controlling cell cycle.

Physicochemical properties and sensory evaluation for the heat level (hot taste) of korean red pepper powder.

This study investigated the heat level rating of several varieties of Korean red peppers. The chemical constitution of Korean red pepper samples were as follows: 0.54∼290.15 mg% capsaicinoids, 79.22∼139.09 ASTA value, and 16.76∼29.92% free sugar content. The heat level of the Korean red pepper samples was evaluated by trained panelists and the correlation coefficient and F value (0.001%) of the panelist’s results were determined to be significant. In the principle component analysis (PCA), PC1 (capsaicinoids) and PC2 (free sugar) were shown to represent 31.98% and 25.77% of the total variance, respectively. The results of panelists trained for red pepper heat rating were evaluated using analysis of variance and correlation analysis. The trained panelists showed a high F value (p=0.05) and high correlation coefficient. A high correlation efficient of 0.84∼0.93 for the test samples with a 40 Scoville heat unit (32,000 SHU red pepper powder) was reported in the sensory evaluation of the Korean red pepper heat level by a trained panel. However, the panel showed a low correlation efficiency of 0.70 R2 when the 60 SHU test samples were included in the analysis.

Neuroprotective Effect of Chuk-Me-Sun-Dan on NMDA- and AMPA-Evoked Nitric Oxide Synthase Activity in Mouse Brain

Chukmesundan (CMSD) is composed of 8 medicinal herbs including Panex ginseng C.A. MEYER, Atractylodes macrocephala KOID, Poria cocos WOLF, Pinellia ternata BREIT, Brassica alba BOISS, Aconitum carmichaeli DEBX, Cynanchum atratum BGE, and Cuscuta chinensis LAM and used for the treatment of various symptoms accompanying hypertension and cerebrovascular disorders. This study was carried out to examine the effects of CMSD on N-methyl-D-aspartate (NMDA)-evoked, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-evoked nitric oxide synthase (NOS) activity in mouse brain. In adult forebrain, CMSD influences neuronal maintenance and is neuroprotective in several injury models through mechanisms that are incompletely understood. Interaction is observed between CMSD and nitric oxide (NO). Because NO affects both neural plasticity and degeneration, we hypothesized that CMSD might rapidly modulate NO production. Using in vivo microdialysis we measured conversion of L-[14C]arginine to L-[14C]citrulline as an accurate reflection of NOS activity in adult mouse hippocampus. CMSD significantly reduced NOS activities to 62% of basal levels within 2 days of onset of delivery and maintained NOS activity at less than 45% of baseline throughout 3 days of delivery. These effects did not occur with control (distilled water) and were not mediated by effect of CMSD on glutamate levels. In addition, simultaneous delivery of CMSD treatment prevented significant increases in NOS activity triggered by the glutamate receptor agonists NMDA and AMPA. Rapid suppression by CMSD of basal and glutamate-stimulated NOS activity may regulate neuromodulatory functions of NO or protect neurons from NO toxicity and suggests a novel mechanism for rapidly mediating functions of CMSD. It is shown that NMDA receptor stimulation leads to activation of p21ras (Ras) through generation of NO via neuronal NOS. The competitive NOS inhibitor, L-nitroarginine methyl ester, and CMSD prevents Ras activation elicited by NMDA, thus supporting the physiologic relevance of endogenous NO regulation of Ras. These results suggest that Ras is a physiologic target of endogenously produced NO and indicates a signaling pathway for NMDA receptor activation that may be important for long-lasting neuronal responses.

Bee Venom Inhibits Porphyromonas gingivalis Lipopolysaccharides-Induced Pro-Inflammatory Cytokines through Suppression of NF-κB and AP-1 Signaling Pathways

Periodontitis is a chronic inflammatory disease that leads to destruction of tooth supporting tissues. Porphyromonas gingivalis (P. gingivalis), especially its lipopolysaccharides (LPS), is one of major pathogens that cause periodontitis. Bee venom (BV) has been widely used as a traditional medicine for various diseases. Previous studies have demonstrated the anti-inflammatory, anti-bacterial effects of BV. However, a direct role and cellular mechanism of BV on periodontitis-like human keratinocytes have not been explored. Therefore, we investigated the anti-inflammatory mechanism of BV against P. gingivalis LPS (PgLPS)-induced HaCaT human keratinocyte cell line. The anti-inflammatory effect of BV was demonstrated by various molecular biological methods. The results showed that PgLPS increased the expression of Toll-like receptor (TLR)-4 and pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, and interferon (IFN)-γ. In addition, PgLPS induced activation of the signaling pathways of inflammatory cytokines-related transcription factors, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activator protein 1 (AP-1). BV effectively inhibited those pro-inflammatory cytokines through suppression of NF-κB and AP-1 signaling pathways. These results suggest that administration of BV attenuates PgLPS-induced inflammatory responses. Furthermore, BV may be a useful treatment to anti-inflammatory therapy for periodontitis.

Incidental Finding of Appendiceal Adenocarcinoma in F-18 FDG PET/CT for Health Screening

F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) that simultaneously offers anatomic and metabolic information is widely used and has become an effective modality in many clinical fields, especially oncology, and also may detect an unexpected primary cancer. Appendiceal carcinoma is relatively uncommon and not associated with characteristic symptoms. We report the case of a 53-year-old man with appendiceal adenocarcinoma, who had only mild fever. The tumor was detected early on F-18 FDG PET/CT for health screening.