A randomized phase III trial comparing adjuvant single-agent S1, S-1 with oxaliplatin, and postoperative chemoradiation with S-1 and oxaliplatin in patients with node-positive gastric cancer after D2 resection: the ARTIST 2 trial☆.

BACKGROUND: Adjuvant chemotherapy and chemoradiotherapy are some of the standards of care for gastric cancer (GC). The Adjuvant chemoRadioTherapy In Stomach Tumors (ARTIST) 2 trial compares two adjuvant chemotherapy regimens and chemoradiotherapy in patients with D2-resected, stage II or III, node-positive GC. PATIENTS AND METHODS: The ARTIST 2 compared, in a 1:1:1 ratio, three adjuvant regimens: oral S-1 (40-60 mg twice daily 4 weeks on/2 weeks off) for 1 year, S-1 (2 weeks on/1 week off) plus oxaliplatin 130 mg/m2 every 3 weeks (SOX) for 6 months, and SOX plus chemoradiotherapy 45 Gy (SOXRT). Randomization was stratified according to surgery type (total or subtotal gastrectomy), pathologic stage (II or III), and Lauren histologic classification (diffuse or intestinal/mixed). The primary endpoint was disease-free survival (DFS) at 3 years; a reduction of 33% in the hazard ratio (HR) for DFS with SOX or SOXRT, when compared with S-1, was considered clinically meaningful. The trial is registered at clinicaltrials.gov (NCT0176146). RESULTS: A total of 546 patients were recruited between February 2013 and January 2018 with 182, 181, and 183 patients in the S-1, SOX, and SOXRT arms, respectively. Median follow-up period was 47 months, with 178 DFS events observed. Estimated 3-year DFS rates were 64.8%, 74.3%, and 72.8% in the S-1, SOX, and SOXRT arms, respectively. HR for DFS in the control arm (S-1) was shorter than that in the SOX and SOXRT arms: S-1 versus SOX, 0.692 (P = 0.042) and S-1 versus SOXRT, 0.724 (P = 0.074). No difference in DFS was found between SOX and SOXRT (HR 0.971; P = 0.879). Adverse events were as anticipated in each arm, and were generally well-tolerated and manageable. CONCLUSIONS: In patients with curatively D2-resected, stage II/III, node-positive GC, adjuvant SOX or SOXRT was effective in prolonging DFS, when compared with S-1 monotherapy. The addition of radiotherapy to SOX did not significantly reduce the rate of recurrence after D2 gastrectomy.

Laparoscopic sentinel node navigation surgery versus laparoscopic gastrectomy with lymph node dissection for early gastric cancer: short-term outcomes of a multicentre randomized controlled trial (SENORITA).

BACKGROUND: Sentinel node navigation surgery reduces the extent of gastric and lymph node dissection, and may improve quality of life. The benefit and harm of laparoscopic sentinel node navigation surgery (LSNNS) for early gastric cancer is unknown. The SENORITA (SEntinel Node ORIented Tailored Approach) trial investigated the pathological and surgical outcomes of LSNNS compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection. METHODS: The SENORITA trial was an investigator-initiated, open-label, parallel-assigned, non-inferiority, multicentre RCT conducted in Korea. The primary endpoint was 3-year disease-free survival. The secondary endpoints, morbidity and mortality within 30 days of surgery, are reported in the present study. RESULTS: A total of 580 patients were randomized to LSG (292) or LSNNS (288). Surgery was undertaken in 527 patients (LSG 269, LSNNS 258). LSNNS could be performed according to the protocol in 245 of 258 patients, and a sentinel node basin was detected in 237 (96·7 per cent) Stomach-preserving surgery was carried out in 210 of 258 patients (81·4 per cent). Postoperative complications occurred in 51 patients in the LSG group (19·0 per cent) and 40 (15·5 per cent) in the LSNNS group (P = 0·294). Complications with a Clavien-Dindo grade of III or higher occurred in 16 (5·9 per cent) and 13 (5·0 per cent) patients in the LSG and LSNNS groups respectively (P = 0·647). CONCLUSION: The rate and severity of complications following LSNNS for early gastric cancer are comparable to those after LSG with lymph node dissection. Registration number: NCT01804998 ( http://www.clinicaltrials.gov).

ANTECEDENTES: La cirugía de navegación del ganglio centinela (sentinel node navigation surgery, SNNS) reduce la extensión de la resección gástrica y ganglionar, y puede mejorar la calidad de vida. Se desconoce el beneficio y el daño de la cirugía de navegación del ganglio centinela por vía laparoscópica (laparoscopic sentinel node navigation surgery, LSNNS) para el cáncer gástrico precoz. El ensayo clínico SENORITA investigó los resultados patológicos y quirúrgicos de LSNNS en comparación con la gastrectomía laparoscópica estándar (laparoscopic gastrectomy, LSG) con disección ganglionar (lymph node dissection, LND). MÉTODOS: El ensayo SENORITA fue un ensayo multicéntrico aleatorizado y controlado, iniciado por investigadores, abierto, con asignación a grupos paralelos y de no inferioridad llevado a cabo en Corea. El resultado primario fue la supervivencia libre de enfermedad a los 3 años. En el presente estudio, se describen los resultados secundarios correspondientes a morbilidad y mortalidad a los 30 días del postoperatorio. RESULTADOS: Un total de 580 pacientes fueron aleatorizados a LG (n = 292) o LSNNS (n = 288). La cirugía se realizó en 527 pacientes (LG 269, LSNNS 258). LSNNS pudo ser realizada de acuerdo con el protocolo en 245 de 258 pacientes y en 237 de 245 pacientes (96,7%) se detectó un ganglio centinela. La cirugía con preservación del estómago se realizó en 210 de 258 pacientes (81,4%). Las complicaciones postoperatorias se presentaron en 51 pacientes del grupo LSG (19,0%) y en 40 pacientes (15,5%) del grupo LSNNS (P = 0,294). Las complicaciones grado III o mayor de Clavien-Dindo se detectaron en 16 (5,9%) y 13 pacientes (5,0%) de los grupos LSG y LSNNS, respectivamente (P = 0,647). CONCLUSIÓN: El porcentaje y la gravedad de las complicaciones tras LSNNS para cancer gástrico precoz son comparables a la LSG con LND.

MicroRNA-328 acts as an anti-oncogene by targeting ABCG2 in gastric carcinoma.

OBJECTIVE: To explore the regulatory mechanism of microRNA-328 expression level by targeting the protein ATP Binding Cassette Transporter G2 (ABCG2) in gastric cancer cells and seek for a biological marker of predicting gastric cancer. PATIENTS AND METHODS: SGC-7901 and MKN-28 human gastric cancer cell lines were cultured. Meanwhile, paired gastric cancer pathological tissues and the corresponding adjacent normal tissues were collected. Western blot analysis was used to validate the protein expression of ABCG2. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) analysis was used to detect the mRNA expression level of miR-328 and ABCG2. Cell counting kit-8 (CCK-8) and colony formation assay were performed to validate the proliferous ability of human gastric cancer cells. The transwell invasion and migration were operated to determine the migratory and invasive capacity. Dual-Luciferase reporter assay, qRT-PCR and Western blot were used to prove the target of miR-328. RESULTS: Bioinformatics analysis made a prediction that ABCG2 was a direct functional target of miR-328. Position 619-625 of ABCG2 3'-UTR had a space structure that was complementary to miR-328 by bioinformatics analysis, and there was a significant reduction in the level of miR-328 in human gastric cancer cell lines and tissues. The expression of miR-328 down-regulated proliferation, invasion and migration of human gastric cancer cells in vitro, while silencing of miR-328 accelerated proliferation, invasion and migration of human gastric cancer cells in vitro. All results displayed ABCG2 was direct target protein of miR-328 owing the binding site and they presented a negative correlation. CONCLUSIONS: ABCG2 is the target protein of miR-328. It presents a negative correlation of the expression level between miR-328 and ABCG2. Down-regulation of miR-328 inhibits the proliferation, invasion and migration of gastric cancer cell lines. MiR-328 could predict generation and development of gastric cancer as a biomarker.

Who may benefit from robotic gastrectomy?: A subgroup analysis of multicenter prospective comparative study data on robotic versus laparoscopic gastrectomy.

AIMS: Robotic gastrectomy for gastric cancer has been proven to be a feasible and safe minimally invasive procedure. However, our previous multicenter prospective study indicated that robotic gastrectomy is not superior to laparoscopic gastrectomy. This study aimed to identify which subgroups of patients would benefit from robotic gastrectomy rather than from conventional laparoscopic gastrectomy. METHODS: A prospective multicenter comparative study comparing laparoscopic and robotic gastrectomy was previously conducted. We divided the patients into subgroups according to obesity, type of gastrectomy performed, and extent of lymph node dissection. Surgical outcomes were compared between the robotic and laparoscopic groups in each subgroup. RESULTS: A total of 434 patients were enrolled into the robotic (n = 223) and laparoscopic (n = 211) surgery groups. According to obesity and gastrectomy type, there was no difference in the estimated blood loss (EBL), number of retrieved lymph nodes, complication rate, open conversion rate, and the length of hospital stay between the robotic and laparoscopic groups. According to the extent of lymph node dissection, the robotic group showed a significantly lower EBL than did the laparoscopic group after D2 dissection (P = 0.021), while there was no difference in EBL in patients that did not undergo D2 dissection (P = 0.365). CONCLUSION: Patients with gastric cancer undergoing D2 lymph node dissection can benefit from less blood loss when a robotic surgery system is used.

Risk factors for double primary malignancies and their clinical implications in patients with sporadic gastric cancer.

AIMS: We carried out a large scale study to identify the risk factors for double primary malignancy (DPM) development in gastric cancer patients and to evaluate the clinical implications for these patients. METHODS: A total of 2593 patients who underwent gastrectomy for primary gastric cancer from January 2005 to November 2010 were reviewed with regard to DPM. We compared the clinicopathological characteristics, risk factors for developing DPM, and prognosis between the DPM+ group and the DPM- group. RESULTS: Of the 2593 patients, 152 (5.9%) were diagnosed with DPM. The most common accompanying malignancies were colorectal, lung and thyroid. Multivariate analysis indicated that age (p = 0.016) and MSI status (p = 0.002) were associated with a higher frequency of DPM. 30.3% of patients were diagnosed with DPM within 1 year around perioperative period and 53.3% of patients had DPM detected during 5 years of post-operative follow up periods. Although there was no significant difference in overall survival between the DPM+ and DPM- group, DPM+ patients had a worse prognosis than DPM- patients in stage I gastric cancer. CONCLUSIONS: Gastric cancer patients over the age of 60 or with a MSI-high status had an increased risk for developing DPM. Further, in stage I gastric cancer, the presence of DPM was associated with a worse prognosis. Therefore, careful pre- and postoperative surveillance is especially important in these patients.

Major early complications following open, laparoscopic and robotic gastrectomy.

BACKGROUND: Laparoscopic and robotic gastrectomy have been adopted rapidly despite lack of evidence concerning technical safety and controversy regarding additional benefits. This study aimed to compare clinically relevant complications after open, laparoscopic and robotic gastrectomy. METHODS: This was a retrospective analysis of prospectively collected data on surgical complications in patients undergoing gastrectomy with curative intent for histologically proven adenocarcinoma between 2005 and 2010 at the Department of Surgery, Yonsei University College of Medicine in Seoul, Korea. Complications were categorized into wound infection, bleeding, anastomotic leak, obstruction, fluid collection and other. RESULTS: In a total of 5839 patients (4542 open, 861 laparoscopic and 436 robotic gastrectomies), overall complication, reoperation and mortality rates were 10·5, 1·0 and 0·4 per cent respectively. There were no significant differences between the three groups. Ileus (P = 0·001) and intra-abdominal fluid collections (P = 0·013) were commoner after conventional open surgery. However, tumour stage was higher and more complex resections were performed in the open group. Anastomotic leak, the leading cause of death, occurred more often after a minimally invasive approach (P = 0·017). CONCLUSION: Laparoscopic and robotic gastrectomy had overall complication and mortality rates similar to those of open surgery, but anastomotic leaks were more common with the minimally invasive techniques.

Impact of pretreatment thrombocytosis on blood-borne metastasis and prognosis of gastric cancer.

BACKGROUND: Thrombocytosis has been associated with malignancies and poor prognostic implications in cancer patients. In the present study the prognostic significance of pretreatment platelet (PLT) level was assessed with regard to recurrence and survival in patients with primary gastric adenocarcinoma. METHODS: The authors reviewed the prospective data of 1593 gastric cancer patients who received curative gastrectomy with extended lymphadenectomy. The correlations of PLT level with recurrence and overall survival were evaluated by both univariate and multivariate analyses. RESULTS: Thrombocytosis (≥ 40 × 10(4)/ µL), present in 6.4% of the patients prior to curative surgery, was more frequently associated with advanced T and N classification, larger tumor size, anemia, and leukocytosis (p < 0.05). In patients with pretreatment thrombocytosis compared to those without it, five-year survival rate was worse (56.9% vs. 65.5%; p = 0.043), and recurrence rate was higher mainly due to the frequent hematogenous spread (51.0% vs. 34.5%; p < 0.001). Furthermore, risk of blood-borne metastasis was almost three-fold higher in patients with pretreatment thrombocytosis (Odds ratio 2.83 [95% CI 1.67-4.77], p < 0.001). CONCLUSIONS: Pretreatment thrombocytosis correlated significantly with poor prognosis and can be used as an independent predictor of recurrence by blood-borne metastasis in gastric cancer.

Relevance of lymph node metastasis along the superior mesenteric vein in gastric cancer.

BACKGROUND: The purpose of this study was to evaluate the prognostic value of lymph node metastasis along the superior mesenteric vein (station 14v) to determine the need for 14v dissection in gastric cancer surgery. METHODS: A total of 1104 patients with gastric cancer who underwent gastrectomy including 14v dissection were enrolled. Patients were categorized into two groups: those with and those without 14v lymph node involvement by metastasis. RESULTS: Of the total study population, 73 patients (6·6 per cent) had 14v-positive gastric cancer. These patients were more likely to have advanced tumour (T), node (N) and distant metastatic (M) status, and histologically undifferentiated gastric cancers. The 3- and 5-year survival rates of patients with 14v-positive disease were 24 and 9 per cent respectively. Survival in this group was similar to that of patients who had gastric cancer with distant metastasis (M1). Multivariable analysis demonstrated that 14v status was a significant prognostic factor for gastric cancer (hazard ratio 2·13; P < 0·001). After histologically complete (R0) resection, the overall survival of 14v-positive patients with any stage of cancer was significantly worse than that for 14v-negative patients with stage IV cancer (P = 0·006). CONCLUSION: 14v status is an independent prognostic factor for gastric cancer, with 14v-positive gastric cancer having a poor prognosis, similar to that of M1 disease. The exclusion of 14v in regional lymph node dissection should be considered.

Indication for endoscopic mucosal resection in early signet ring cell gastric cancer.

BACKGROUND: The aim of this study was to compare the clinicopathological characteristics of an early signet ring cell carcinoma (SRC) with an early undifferentiated carcinoma (mucinous, poorly differentiated adenocarcinoma) and early differentiated carcinoma (well or moderately differentiated tubular adenocarcinoma, papillary adenocarcinoma) and find indications for endoscopic mucosal resection (EMR) in early SRC. METHODS: 1520 patients with early gastric cancer (EGC), who underwent a curative gastrectomy, were analyzed retrospectively. Among them, 388 patients with SRC were compared with 253 patients with undifferentiated carcinoma (UDC) and 879 with a differentiated carcinoma (DC). RESULTS: SRC was more common in young female patients than UDC. SRC had a tendency to be confined to the mucosa, with smaller size than UDC. The lymph node metastasis rate for SRC was lower than that for UDC, but similar to that of DC. Multivariate analysis revealed lymph node metastasis (LNM) to be associated with the depth of invasion, tumor size, histological type, and lymphatic involvement. SRC had no LNM in the case of a mucosal tumor, smaller than 2 cm, and in the absence of lymphatic involvement. The prognosis of SRC was more favorable than UDC. CONCLUSIONS: Early SRC has different characteristics from early UDC. In view of the lower rate of lymph node metastasis and better prognosis, we suggest that EMR can be performed on patients with early SRC limited to the mucosa, less than 2cm in size, and with no lymphatic involvement.

Gastric GIST: a single institutional retrospective experience with surgical treatment for primary disease.

AIMS: Because gastric GISTs show variable clinical behavior, we reviewed our experience with primary gastric GISTs after surgical treatment and imatinib mesylate treatment for advanced disease. METHODS: Between December 1995 and December 2005, 111 patients who underwent surgical treatment for primary gastric GISTs were enrolled in this study. Patients were grouped according to the risk assessment classification, and clinicopathological features, tumor recurrence and patient survival were assessed. RESULTS: One patient was included in the very low risk group, 35 in the low risk group, 31 in the intermediate risk group and 44 in the high-risk group. All patients with very low, low and intermediate risk GISTs and 70% of patients with high risk GISTs underwent R0 resection. While there was no recurrence or metastasis in patients with very low, low and intermediate risk GISTs, 23% of those with high risk GISTs showed a distant metastasis at diagnosis and 35% of these patients had a recurrence after R0 resection. The overall 5-year survival rate of the high risk patients was 77.1%. Nineteen patients received imatinib mesylate therapy due to an incomplete resection or recurrence; 7 with no measurable lesion at the CT scan by a local tumor control showed no tumor progression after imatinib mesylate therapy, however, 12 patients with measurable lesions showed variable clinical courses after treatment. The overall 5-year survival rate of 19 patients with imatinib mesylate treatment was 80.0%. CONCLUSIONS: The clinical outcome of the very low, low and intermediate risk gastric GISTs was excellent, while high risk gastric GISTs had a high rate of recurrence and therefore a less favorable outcome. A complete resection is the most important treatment for cure; however imatinib mesylate treatment may improve the clinical outcome of the patients with metastatic or recurrent gastric GISTs.

Primary malignant retroperitoneal tumors: analysis of a single institutional experience.

AIMS: In order to achieve complete resection in the surgical management of retroperitoneal tumors, it is crucial to know the tumor's anatomical location relative to neighboring organs. METHODS: Forty-nine patients with primary malignant retroperitoneal tumors were divided by tumor location into two groups [upper abdomen (group 1) or lower abdomen (group 2)], and clinicopathological features, tumor recurrence, and patient survival were assessed. RESULTS: No significant differences in preoperative clinical characteristics existed between two groups, and liposarcoma was the most frequently observed tumor type. The difference in the rates of complete resection between the two groups was not statistically significant (75.9% for group 1 and 85% for group 2). En-bloc combined resection was performed in 52% and 30% of patients in groups 1 and 2, respectively. The local recurrence rate in group 2 (31.3%) was higher than that in group 1 (9.5%), despite the fact that the differences in rates of complete resection and distant recurrence rates (14.3% in group 1 and 12.5% in group 2) between the two groups were not statistically significant. The overall 5-year survival rates were 67.9% for group 1 and 43.2% for group 2 (p=0.038). The 5-year survival rate of patients with tumors smaller than 10 cm was 78.4%, while that of patients with tumors larger than 10 cm was 38.1% (p=0.017). The 5-year survival rate after complete excision was 61%, whereas that after incomplete resection or biopsy only was 40.0% (p<0.0001). CONCLUSIONS: An upper abdominal tumor location is a positive prognostic factor even if small tumor size (<10 cm) and complete resection of the tumor are still more important factors to improve outcome in patients with malignant primary retroperitoneal tumors. Because complete resection was shown to be the most important prognostic factor, an aggressive and careful surgical approach is recommended for the treatment of such tumors.

Synthesis, characterization and photodynamic activity of amino-substituted hypocrellin derivatives.

Three new hypocrellin derivatives, amino- or amino acid-substituted on the side ring of hypocrellin B (HB), were synthesized by the reactions of HB with 3-methoxypropylamine, 6-aminohexanoic acid and gamma-amino-n-butyric acid, respectively. The structures of these compounds were characterized with proton nuclear magnetic resonance spectra, infrared spectra and mass spectra. The UV-visible absorption spectra, singlet oxygen-generating quantum yield and amphiphilicities of hypocrellin derivatives were measured and compared with HB, the parent compound. These derivatives showed strong absorption in the domain of the phototherapeutic window (600-900 nm) and improved amphiphilicity. HB and the derivatives were preliminarily tested for their photodynamic effects on human oral cavity epithelial carcinoma KB cell line in vitro. Two amino acid-substituted hypocrellins showed phototoxicity to the KB cell line. At an inhibitory dosage of 50% killing only 0.51 mumol L-1 compound 3 (or 0.88 mumol L-1 compound 2) and 0.5 J cm-2 irradiation were required. The hypocrellins exhibited some dark toxicity to the KB cell line. HB and amino acid-substituted hypocrellins showed lower dark toxicity to the KB cell line than amino-substituted hypocrellins in the assessment of cell survival.

The mechanism of contraction by 2-chloroadenosine in cat detrusor muscle cells.

PURPOSE: Four adenosine receptors (ARs), designated A1AR (A1 adenosine receptor), A2aAR (A2a adenosine receptor), A2bAR (A2b adenosine receptor), and A3AR (A3 adenosine receptor), have been cloned from various species, but the contraction mechanism via A1ARs in cat detrusor muscle cell is not well known. MATERIALS AND METHODS: We examined the cellular mechanism using an A1AR agonist 2-chloroadenosine (2-CA) in cat detrusor cell isolated by enzymatic digestion. To examine which phospholipase mediates the contraction, we used phospholipase inhibitors. RESULTS: The adenosine analog potency order is R-N6-phenylisopropyladenosine (R-PIA) > 5'-N-ethylcarbosamine adenosine (NECA) > 2-chloroadenosine (2-CA) > S-N6-phenylisopropyladenosine (S-PIA). The ratio of equi-effective concentrations of R-PIA/S-PIA was 58.2. 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 300 nM) shifted to the right the concentration-response curves of 2-CA. These results indicate A1ARs mediate 2-CA induced contraction in cat detrusor muscle. G proteins (Gi1, Gi2, Gi3, Go, Gs, and Gq) in cat detrusor muscle were detected by immunoblot analysis. Pertussis toxin (PTX) inhibited 2-CA induced contraction. In permeabilized cells, antibodies against Galphai3 antagonized 2-CA induced contraction, suggesting that the contraction is mediated by Gi3 protein. A phosphatidylinositol-specific phospholipase C (PLC) inhibitor, neomycin, reduced 2-CA induced contraction, but a phospholipase D (PLD) inhibitor, p-chloromercuribenzoic acid, and a phospholipase A2 (PLA2) inhibitor, dimethyl-eicosa-dienoic acid (DEDA), had no effect. We found the presence of the main PLC isozymes, PLC-beta1, PLC-beta3, and PLC-gamma1. 2-CA induced contraction in permeabilized cells was inhibited by PLC-beta3 but not by PLC-beta1 or PLC-gamma1 antibody. These results imply that A1ARs are coupled to PLC-beta3 via PTX-sensitive Gi3 protein. Sr2+ medium and thapsigargin, which replaces intracellular Ca2+ and deplete intracellular calcium stores respectively, inhibited 2-CA induced contraction. CONCLUSIONS: These results suggest that A1ARs mediating 2-CA induced contraction exist in cat detrusor muscle and the contraction depends on a PTX-sensitive Gi3 protein, PLC-beta3 and the release of intracellular Ca2+.

Glycoconjugated hypocrellin: synthesis of [(beta-D-glucosyl)ethylthiyl]hypocrellins and photosensitized generation of singlet oxygen.

In order to improve the water solubility and specific affinity for malignant tumors of hypocrellin, glycoconjugated hypocrellins have been synthesized using an improved Königs-Knörr reaction from mercaptoethanol substituted hypocrellin B and 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide precursors. Deprotection of glucose moieties allows the production of derivatives which had improved solubility in neutral aqueous solution and covered a range of amphiphilic character. The structures of these new protected and unprotected compounds were characterized by UV-Vis, IR, 1H-NMR and MS data. The present strategy should prove applicable to the synthesis of other glycoconjugated perylenequinone compounds. In addition, the quantum yield of singlet oxygen generation photosensitized by these glycoconjugated hypocrellins has been determined.

Pharmacokinetics, tissue distribution and photodynamic therapy efficacy of liposomal-delivered hypocrellin A, a potential photosensitizer for tumor therapy.

Hypocrellin A, from Hypocrella bambusae, is a novel photosensitizer of high singlet oxygen quantum yield for photodynamic therapy (PDT). Tissue distributions were studied in tumor-bearing mice as a function of time following administration. The tumor model was S-180 sarcoma transplanted into one hind leg of male Kunming mice; hypocrellin A (HA) was delivered to the mice by intravenous injection of 5 mg/kg of body weight as a suspension either as a unilamellar liposome or in dimethyl sulfoxide (DMSO)-solubilized saline. The HA was isolated from several tissues and organs, as well as tumors and peritumoral muscles and skin. Quantitation was performed by a high-performance liquid chromatographic technique with detection that utilizes the native fluorescence of HA. Independent of the delivery system, the dye was retained in tumors at higher concentrations than in normal tissues, except for kidney, liver, lung and spleen. The dye retention in tumors was high and was vehicle dependent. For the liposomal system, the maximal accumulation in tumor and maximal ratios of dye in tumor versus peritumoral muscle and skin occurred 12 h postinjection; for the DMSO saline system, the maximal ratio occurred earlier, 6 h postadministration. Liposomal delivery improved the selective accumulation of the dye in tumor with higher maximal levels in tumor and higher ratios of tumor-to-muscle and tumor-to-skin. Levels of dye were very low or not detectable in the brain. The PDT efficacy of HA in the liposome and DMSO saline systems was determined by evaluating the tumor volume regression percent. The PDT efficacy of HA in liposomes was highest when light treatment was performed at 12 h postinjection, consistent with the highest retention of HA in tumors. Similarly, the maximal PDT efficacy in DMSO saline was attained at 6 h postinjection, the highest HA retention point in tumor. Moreover, the peak PDT efficacy of HA in liposomes was much higher than that of HA in DMSO saline and even hematoporphyrin monomethylether.

Electric magnetic resonance and spectrophotometry evidence on the photodynamic activity of a new perylenequinonoid pigment.

Di-cysteine substituted hypocrellin B (DCHB) is a new water-soluble photosensitizer with significantly enhanced red absorption at wavelengths longer than 600 nm over the parent compound hypocrellin B (HB). The photosensitizing properties (Type I and/or Type II mechanisms) of DCHB have been investigated in dimethylsulfoxide (DMSO) and aqueous solution (pH 7.4) using electron paramagnetic resonance (EPR) and spectrophotometric methods. In anaerobic DMSO solution, the semiquinone anion radical of DCHB (DCHB-) is predominantly photoproduced via self-electron transfer between excited- and ground-state DCHB species. The presence of an electron donor significantly promotes the formation of the reduced form of DCHB. When a deoxygenated aqueous solution of DCHB and an electron door are irradiated with 532 nm light, the hydroquinone of DCHB (DCHBH2) is formed via the disproportionation of the first-formed DCHB- and second electron transfer to DCHB- and second electron transfer to DCHB- from the electron donor. When oxygen is present, singlet oxygen (1 O2), superoxide anion radical (O2-) and hydroxyl radical (OH) are produced. The quantum yield of 1 O2 generation by DCHB photosensitization is estimated to be 0.54 using Rose Bengal as a reference, a little lower than that of HB (0.76). The superoxide anion radical is also significantly enhanced by the presence of electron donors. Moreover, O2- upon disproportionation generated H2O2 and ultimately the highly reactive OH via the Haber-Weiss reaction pathway. The efficiency of O2- generation by DCHB is obviously enhanced over that of HB. These findings suggest that the photodynamic actions of DCHB may proceed via type I and Type II mechanisms and that this new photosensitizer retains photosensitizing activity after photodynamic therapy-oriented chemical modification.

EPR and spectrophotometric studies on free radicals (O2.-, Cysa-HB.-) and singlet oxygen (1O2) generated by irradiation of cysteamine substituted hypocrellin B.

PURPOSE: The aim of this work was to investigate the photodynamic action of cysteamine substituted hypocrellin B (Cysa-HB) photochemically and survey the effect of oxygen on its reaction mechanism. MATERIALS AND METHODS: The EPR method is used to detect the generation of the semiquinone anion radical of Cysa-HB (Cysa-HB.-), and active oxygen species using DMPO and TEMP as spin traps. DPA-bleaching method is used to determine the quantum yield of 1O2 generated from Cysa-HB photosensitization. RESULTS: In anaerobic solution, Cysa-HB.- was predominantly photoproduced via the self-electron transfer between the excited and ground state species. The presence of electron donors significantly promotes the reduced form of Cysa-HB. When oxygen-saturated solutions of Cysa-HB were illuminated with visible light, superoxide anion radical (O2.-) and singlet oxygen (1O2) were formed. The superoxide anion radical was generated by Cysa-HB.- via electron transfer to oxygen, and this process was significantly enhanced by the presence of electron donors. The 1O2 quantum yield is estimated to be 0.71. Moreover, the accumulation of 1O2 will be replaced by that of Cysa-HB.- with the depletion of oxygen. CONCLUSIONS: These observations suggest that the photodynamic action of Cysa-HB may proceed via both a Type I and Type II mechanism, and that a Type II mechanism will transform into a Type I mechanism as oxygen gets depleted.

Studies on the chelation of hypocrellin A with aluminium ion and the photodynamic action of the resulting complex.

Hypocrellin A (HA), a perylenoquinone derivative, is an efficient phototherapeutic agent. The chelation of HA with aluminium ion (Al3+) results in the formation of a 1:1 complex (Al(3+)-HA). The probable structure for this complex has been proposed. Compared with HA, this complex has a much higher solubility in water. In addition, Al(3+)-HA preserves the 1O2-generating function of HA as demonstrated by diphenylanthracene photo-bleaching experiments. In irradiated oxygen-saturated solutions of Al(3+)-HA superoxide radical anion and hydroxyl radical are formed as verified using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the electron spin resonance (ESR) spin trapping agent. The production of superoxide radical anion is enhanced significantly in the presence of electron donors such as 1-benzyl-1,4-dihydronicotinamide (BNAH). These results suggest that the photodynamic action of Al(3+)-HA proceeds via both type 1 and type 2 reactions.