Inhibiting Bruton's Tyrosine Kinase to Counteract Chemoresistance and Stem Cell-Like Properties in Osteosarcoma.

Osteosarcoma, a highly aggressive bone cancer, often develops resistance to conventional chemotherapeutics, leading to poor prognosis and survival rates. The malignancy and chemoresistance of osteosarcoma pose significant challenges in its treatment, highlighting the critical need for novel therapeutic approaches. Bruton's tyrosine kinase (BTK) plays a pivotal role in B-cell development and has been linked to various cancers, including breast, lung, and oral cancers, where it contributes to tumor growth and chemoresistance. Despite its established importance in these malignancies, the impact of BTK on osteosarcoma remains unexplored. Our study delves into the expression levels of BTK in osteosarcoma tissues by data from the GEO and TCGA database, revealing a marked increase in BTK expression compared with primary osteoblasts and a potential correlation with primary site progression. Through our investigations, we identified a subset of osteosarcoma cells, named cis-HOS, which exhibited resistance to cisplatin. These cells displayed characteristics of cancer stem cells (CSCs), demonstrated a higher angiogenesis effect, and had an increased migration ability. Notably, an upregulation of BTK was observed in these cisplatin-resistant cells. The application of ibrutinib, a BTK inhibitor, significantly mitigated these aggressive traits. Our study demonstrates that BTK plays a crucial role in conferring chemoresistance in osteosarcoma. The upregulation of BTK in cisplatin-resistant cells was effectively countered by ibrutinib. These findings underscore the potential of targeting BTK as an effective strategy to overcome chemoresistance in osteosarcoma treatment.

Visfatin Facilitates VEGF-D-Induced Lymphangiogenesis through Activating HIF-1α and Suppressing miR-2277-3p in Human Chondrosarcoma.

Chondrosarcoma is a malignant bone tumor that arises from abnormalities in cartilaginous tissue and is associated with lung metastases. Lymphangiogenesis plays an essential role in cancer metastasis. Visfatin is an adipokine reported to enhance tumor metastasis, but its relationship with VEGF-D generation and lymphangiogenesis in chondrosarcoma remains undetermined. Our results from clinical samples reveal that VEGF-D levels are markedly higher in chondrosarcoma patients than in normal individuals. Visfatin stimulation promotes VEGF-D-dependent lymphatic endothelial cell lymphangiogenesis. We also found that visfatin induces VEGF-D production by activating HIF-1α and reducing miR-2277-3p generation through the Raf/MEK/ERK signaling cascade. Importantly, visfatin controls chondrosarcoma-related lymphangiogenesis in vivo. Therefore, visfatin is a promising target in the treatment of chondrosarcoma lymphangiogenesis.

Nonpermissive Skin Environment Impairs Nerve Regeneration in Diabetes via Sec31a.

OBJECTIVE: Although the microenvironment for peripheral nerve regeneration is permissive, such a mechanism is defective in diabetes, and the molecular mediators remain elusive. [Correction added on May 11, 2022, after first online publication: In the preceding sentence, "is ok" was changed to "is defective".] This study aimed to (1) investigate the relationship between skin innervation and collagen pathology in diabetic neuropathy and to (2) clarify the molecular alterations that occur in response to hyperglycemia and their effects on axon regeneration. METHODS: We addressed this issue using two complementary systems: (1) human skin from patients with diabetic neuropathy and to (2) a coculture model of human dermal fibroblasts (HDFs) with rat dorsal root ganglia neurons in the context of intrinsic neuronal factor and extrinsic microenvironmental collagen and its biosynthetic pathways. RESULTS: In diabetic neuropathy, the skin innervation of intraepidermal nerve fiber density (IENFd), a measure of sensory nerve degeneration, was reduced with similar expression of a growth associated protein 43, a marker of nerve regeneration. In contrast, the content and packing of collagen in the diabetic skin became more rigid than the control skin. Sec31a, a protein that regulates the collagen biosynthetic pathway, was upregulated and inversely correlated with IENFd. In the cell model, activated HDFs exposed to high-glucose medium enhanced the expression of Sec31a and collagen I through the activation of transforming growth factor ß, a profibrotic molecule. Sec31a upregulation impaired neurite outgrowth. This effect was reversed by silencing Sec31a expression and neurite outgrowth was resumed. INTERPRETATION: The current study provides evidence that Sec31a plays a key role in inhibiting nerve regeneration in diabetic neuropathy. ANN NEUROL 2022;91:821-833.

Lysosomal-targeted doxorubicin delivery using RBC-derived vesicles to overcome drug-resistant cancer through mitochondrial-dependent cell death.

Multidrug resistance (MDR) is a major challenge in cancer chemotherapy. Nanoparticles as drug delivery systems (DDSs) show promise for MDR cancer therapy. However, current DDSs require sophisticated design and construction based on xenogeneic nanomaterials, evoking feasibility and biocompatibility concerns. Herein, a simple but versatile biological DDS (bDDS) composed of human red blood cell (RBC)-derived vesicles (RDVs) with excellent biocompatibility was surface-linked with doxorubicin (Dox) using glutaraldehyde (glu) to form Dox-gluRDVs that remarkably suppressed MDR in uterine sarcoma through a lysosomal-mitochondrial axis-dependent cell death mechanism. Dox-gluRDVs can efficiently deliver and accumulate Dox in lysosomes, bypassing drug efflux transporters and facilitating cellular uptake and retention of Dox in drug-resistant MES-SA/Dx5 cells. The transfer of lysosomal calcium to the mitochondria during mitochondria-lysosome contact due to lysosomal Dox accumulation may result in mitochondrial ROS overproduction, mitochondrial membrane potential loss, and activation of apoptotic signaling for the superior anti-MDR activity of Dox-gluRDVs in vitro and in vivo. This work highlights the great promise of RDVs to serve as a bDDS of Dox to overcome MDR cancers but also opens up a reliable strategy for lysosomal-mitochondrial axis-dependent cell death for fighting against other inoperable cancers.

Alkaloids and Polyacetylenes from Hippobroma longiflora with Antiangiogenesis Properties.

Four new alkaloids, hippobrines A-D (1-4), along with three new polyacetylenes, hippobrenes A-C (5-7), were isolated from Hippobroma longiflora. Compounds 1-3 possess an unprecedented carbon skeleton. All of the new structures were determined by analyzing their mass and NMR spectroscopic data. The absolute configurations of 1 and 2 were confirmed by single-crystal X-ray analyses, and the absolute configurations of 3 and 7 were deduced using their ECD spectra. Plausible biogenetic pathways of 1 and 4 were proposed. In regard to bioactivities, all compounds (1-7) exhibited weak antiangiogenic activity against human endothelial progenitor cells, with IC50 values ranging from 21.1 ± 1.1 to 44.0 ± 2.3 µg/mL.

Geographic distance, sedimentation, and substrate shape cryptic crustose coralline algal assemblages in the world's largest subtropical intertidal algal reef.

Algal reefs, concreted by crustose coralline algae (CCA), are the main biotic reefs in temperate waters but rare in the subtropics and tropics. The world's largest known intertidal algal reef in the subtropics is the Taoyuan Algal Reef (TAR) located in the northwestern coast of Taiwan. The biodiversity and ecology of the TAR are scarcely explored, and now the reef is imperiled by industrialization. Here, we document cryptic species of CCA in Taiwan, particularly the TAR, by sequencing the psbA genes of over 1800 specimens collected across Taiwan. We also examine the ecological background of the TAR by surveying its benthic composition and measuring its environmental parameters. Our data reveal that the TAR harbours a high diversity of cryptic CCA species (27 molecular operational taxonomic units, or mOTUs), many of which are potentially new to science (18 mOTUs) and/or endemic to the TAR (9 mOTUs). Comparing the CCA species inventory of the TAR with the rest of Taiwan shows that the TAR represents a unique hotspot of CCA taxa in the waters of Taiwan. Our analyses show that variation in the CCA assemblages in the TAR is associated with geographic distance, sedimentation, and substrate type (for example, reef vs. hermit crab shell), suggesting that dispersal limitation and contemporary environmental selection shape the CCA assemblages in the TAR. The data from this study can inform the monitoring of human impacts on the health of the TAR and contribute to our understanding of the ecological processes underlying algal reef development.

Melatonin suppresses the metastatic potential of osteoblastic prostate cancers by inhibiting integrin α2 ß1 expression.

Advanced prostate cancer often develops into bone metastasis, which is characterized by aberrant bone formation with chronic pain and lower chances of survival. No treatment exists as yet for osteoblastic bone metastasis in prostate cancer. The indolamine melatonin (N-acetyl-5-methoxytryptamine) is a major regulator of the circadian rhythm. Melatonin has shown antiproliferative and antimetastatic activities but has not yet been shown to be active in osteoblastic bone lesions of prostate cancer. Our study investigations reveal that melatonin concentration-dependently decreases the migratory and invasive abilities of two osteoblastic prostate cancer cell lines by inhibiting FAK, c-Src, and NF-κB transcriptional activity via the melatonin MT1 receptor, which effectively inhibits integrin α2 ß1 expression. Melatonin therapy appears to offer therapeutic possibilities for reducing osteoblastic bone lesions in prostate cancer.

New Trichothecenes Isolated from the Marine Algicolous Fungus Trichoderma brevicompactum.

Eight trichothecenes, including four new compounds 1-4 and four known entities 5-8, together with one known cyclonerane (9) were isolated from the solid-state fermentation of Trichoderma brevicompactum NTU439 isolated from the marine alga Mastophora rosea. The structures of 1-9 were determined by 1D/2D NMR (nuclear magnetic resonance), MS (mass spectrometry), and IR (infrared spectroscopy) spectroscopic data. All of the compounds were evaluated for cytotoxic activity against HCT-116, PC-3, and SK-Hep-1 cancer cells by the SRB assay, and compound 8 showed promising cytotoxic activity against all three cancer cell lines with the IC50 values of 3.3 ± 0.3, 5.3 ± 0.3, and 1.8 ± 0.8 µM, respectively. Compounds 1-2, 4-6, and 7-8 potently inhibited LPS-induced NO production, and compounds 5 and 8 showed markedly inhibited gelatinolysis of MMP-9 in S1 protein-stimulated THP-1 monocytes.

4-Acetylantroquinonol B Suppresses Prostate Cancer Growth and Angiogenesis via a VEGF/PI3K/ERK/mTOR-Dependent Signaling Pathway in Subcutaneous Xenograft and In Vivo Angiogenesis Models.

Prostate cancer is a major cause of cancer-related mortality in men in developed countries. The compound, 4-acetylantroquinonol B (4AAQB), is isolated from Antrodia cinnamomea (commonly known as Niu-Chang-Chih), which has been shown to inhibit cancer growth. However, the anticancer activity of 4AAQB has not previously been examined in prostate cancer. This study aimed to investigate the effect of 4AAQB on cancer and angiogenesis, as well as to explore its mechanism of action. Human prostate cancer cells (PC3) and human umbilical vein endothelial cells (HUVEC) were used in cell viability, cell migration, and cell cycle functional assays to evaluate the anticancer and antiangiogenic efficacy of 4AAQB in vitro. The effects of 4AAQB in vivo were determined using xenograft and angiogenesis models. The signaling events downstream of 4AAQB were also examined. The 4AAQB compound inhibited PC3 cell growth and migration, and reduced in vivo cancer growth, as shown in a subcutaneous xenograft model. Furthermore, 4AAQB inhibited HUVEC migration, tube formation, and aortic ring sprouting; it also reduced neovascularization in a Matrigel implant angiogenesis assay in vivo. The 4AAQB compound also decreased metastasis in the PC3 prostate cancer model in vivo. Serum or vascular endothelial growth factor (VEGF)-induced VEGF receptor 2 (VEGFR2), phosphoinositide 3-kinase (PI3K)/Ak strain transforming (Akt), and extracellular signal-regulated kinase ½ (ERK ½) phosphorylation were attenuated by 4AAQB in both PC3 and HUVEC. In conclusion, 4AAQB is a potential candidate for prostate cancer therapy.

Chemical Constituents and Anti-Angiogenic Principles from a Marine Algicolous Penicillium sumatraense SC29.

In this study, a marine brown alga Sargassum cristaefolium-derived fungal strain, Penicillium sumatraense SC29, was isolated and identified. Column chromatography of the extracts from liquid fermented products of the fungal strain was carried out and led to the isolation of six compounds. Their structures were elucidated by spectroscopic analysis and supported by single-crystal X-ray diffraction as four previously undescribed (R)-3-hydroxybutyric acid and glycolic acid derivatives, namely penisterines A (1) and C-E (3-5) and penisterine A methyl ether (2), isolated for the first time from natural resources, along with (R)-3-hydroxybutyric acid (6). Of these compounds identified, penisterine E (5) was a unique 6/6/6-tricyclic ether with an acetal and two hemiketal functionalities. All the isolates were subjected to in vitro anti-angiogenic assays using a human endothelial progenitor cell (EPCs) platform. Among these, penisterine D (4) inhibited EPC growth, migration, and tube formation without any cytotoxic effect. Further, in in vivo bioassays, the percentages of angiogenesis of compound 3 on Tg (fli1:EGFP) transgenic zebrafish were 54% and 37% as the treated concentration increased from 10.2 to 20.4 µg/mL, respectively, and the percentages of angiogenesis of compound 4 were 52% and 41% as the treated concentration increased from 8.6 to 17.2 µg/mL, respectively. The anti-angiogenic activity of penisterine D (4) makes it an attractive candidate for further preclinical investigation.

CXC chemokine ligand-13 promotes metastasis via CXCR5-dependent signaling pathway in non-small cell lung cancer.

The CXC chemokine ligand-13 (CXCL13) is a chemoattractant of B cells and has been implicated in the progression of many cancers. So far, CXCL13 and its related receptor CXCR5 have been proved to regulate cancer cell migration as well as tumour metastasis. However, the role of CXCL13-CXCR5 axis in metastasis of lung cancer is still poorly understood. In this study, we found that CXCL13 and CXCR5 were commonly up-regulated in lung cancer specimens compared with normal tissues among different cohorts. Our evidence showed that CXCL13 obviously promoted migration of lung cancer cells, and this effect was mediated by vascular cell adhesion molecule-1 (VCAM-1) expression. We also confirmed that CXCR5, the major receptor responsible for CXCL13 function, was required for CXCL13-promoted cell migration. We also test the candidate components which are activated after CXCL13 treatment and found that phospholipase C-ß (PLCß), protein kinase C-α (PKCα) and c-Src signalling pathways were involved in CXCL13-promoted cell migration and VCAM-1 expression in lung cancer cells. Finally, CXCL13 stimulated NF-κB transcription factor in lung cancer cells, contributing to VCAM-1 expression in translational level. These evidences propose a novel insight into lung cancer metastasis which is regulated by CXCL13.

Melatonin impedes prostate cancer metastasis by suppressing MMP-13 expression.

Prostate cancer has high metastatic potential. Men with higher urinary levels of the sleep hormone melatonin are much less likely to develop advanced prostate cancer compared with men with lower levels of melatonin. Melatonin has shown anticancer activity in experimental investigations. Nevertheless, the therapeutic effect of melatonin in metastatic prostate cancer has largely remained a mystery. Analyses of Gene Expression Omnibus data and human tissue samples indicated that levels of matrix metallopeptidase 13 (MMP-13) expression are higher in prostate cancer patients than in healthy cancer-free individuals. Mechanistic investigations revealed that melatonin inhibits MMP-13 expression and the migratory and invasive capacities of prostate cancer cells via the MT1 receptor and the phospholipase C, p38, and c-Jun signaling cascades. Importantly, tumor growth rate and metastasis to distant organs were suppressed by melatonin in an orthotopic prostate cancer model. This is the first demonstration showing that melatonin impedes metastasis of prostate cancer by suppressing MMP-13 expression in both in vitro and in vivo models. Thus, melatonin is promising in the management of prostate cancer metastasis and deserves to undergo clinical investigations.

Resistin enhances IL-1ß and TNF-α expression in human osteoarthritis synovial fibroblasts by inhibiting miR-149 expression via the MEK and ERK pathways.

Resistin is a cysteine-rich adipokine that promotes the release of inflammatory cytokines, particularly interleukin 1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α), which are critical pro-inflammatory mediators in osteoarthritis (OA) pathogenesis. We describe evidence of significantly higher levels of resistin, IL-1ß, and TNF-α expression in OA knee synovial tissue compared with that from non-OA knees. Resistin-induced enhancement of IL-1ß and TNF-α expression in human OA synovial fibroblasts (OASFs) were attenuated by MEK and ERK inhibitors, as well as their respective siRNAs. Our data reveal that resistin enhances the expression of TNF-α and IL-1ß in OASFs by inhibiting miR-149 expression via MEK and ERK signaling. Our findings elucidate the inter-relationships between resistin and pro-inflammatory mediators during OA pathogenesis and could help to facilitate the development of synovium-targeted therapy in OA.

Effect of phenylurea hydroxamic acids on histone deacetylase and VEGFR-2.

A series of phenylurea hydroxamic acids incorporating pharmacophores of inhibitors of HDAC inhibitors and VEGFR-2 has been designed. Most of the compounds show antiproliferative activity comparable to that of Vorinostat and Sorafenib, and better EPC inhibitory activity. Enzymatic assays and Western blotting results indicated that compound 14 not only inhibits HDAC but also has slight VEGFR-2 inhibitory activity. A docking study revealed that the polar hydroxamic acid retains the interaction with HDAC through a zinc ion and also interacts with some residues of the active site of VEGFR-2. Despite 14 displaying a weaker VEGFR-2 activity, a possible route to develop potent HDAC/VEGFR-2 inhibitors is suggested.

Additional alkaloids from Zoanthus vietnamensis with neuroprotective and anti-angiogenic effects.

A chemical investigation of the zoantharian Zoanthus vietnamensis, collected off Taiwan, yielded eleven new alkaloids, 7α-hydroxykuroshine J (1), 18ß-hydroxykuroshine J (2), 5α-hydroxyzoanthenamine (3), 5ß-hydroxyzoanthenamine (4), 14α-hydroxyzoanthenamine (5), 30-hydroxyzoanthenamine (6), 11-dehydroxy-18-epi-kuroshine A (7), 5α-hydroxykuroshine A (8), 7ß-hydroxykuroshine A (9), 11-keto-oxyzoanthamine (10), and 30-hydroxyzoanthamine (11), along with eight known compounds (12-19). The structures of these compounds were identified by detailed spectroscopic data, including HRESIMS, IR, NMR, and UV spectra. All secondary metabolites isolated from Z. vietnamensis were investigated for the anti-angiogenic effect in human endothelial progenitor cells (EPCs). Compounds 6, 7, 11, and 13 exhibited mild anti-angiogenic effect by blocking cell growth and tube formation of EPCs. The neuroprotective potential of four major compounds 12, 14, 15, and 19 against paclitaxel-induced neurotoxicity was evaluated. Pretreatment of 14 and 15 protected paclitaxel-damaged neurite outgrowth of dorsal root ganglion (DRG) neurons, without interfering the cytotoxic activity of paclitaxel on cervical cancer SiHa cells.

Prostate cancer-secreted CCN3 uses the GSK3ß and ß-catenin pathways to enhance osteogenic factor levels in osteoblasts.

Prostate cancer osteoblastic bone metastases are incurable and associated with chronic bone pain and a high mortality rate. Osteoclast-targeting drugs intended to prevent skeletal-related events associated with prostate cancer bone metastases do not prolong overall survival. Improved understanding of the bone-derived factors that contribute to prostate cancer osteoblastic bone metastases is required to design treatments that will improve morbidities and overall survival. Activated osteoblasts stimulate prostate cancer growth in bone. In this study, we report that prostate cancer conditioned medium (CM) promoted bone morphogenetic protein (BMP)-2, -4 and -7 production and the expression of osteogenic transcription factors Runx2 and osterix in osteoblasts. Treating the prostate cancer CM with antibody against CCN3 (nephroblastoma-overexpressed), a cysteine-rich protein that belongs to the CCN family, reduced all of these increases. Incubation of osteoblasts with CCN3 facilitated phosphorylation of GSK3ß and ß-catenin. GSK3ß and ß-catenin inhibitors or siRNAs all abolished CCN3-induced promotion of BMPs, Runx2 and osterix expression in osteoblasts. Our results indicate that prostate cancer-secreted CCN3 enhances BMP, Runx2 and osterix expression in osteoblasts via the GSK3ß and ß-catenin signaling pathways. This understanding of the role played by CCN3 in osteoblastic prostate bone metastasis may lead to more efficient targeted therapies.

Moscatilin Inhibits Metastatic Behavior of Human Hepatocellular Carcinoma Cells: A Crucial Role of uPA Suppression via Akt/NF-κB-Dependent Pathway.

Hepatocellular carcinoma (HCC) frequently shows early invasion into blood vessels as well as intrahepatic metastasis. Innovations of novel small-molecule agents to block HCC invasion and subsequent metastasis are urgently needed. Moscatilin is a bibenzyl derivative extracted from the stems of a traditional Chinese medicine, orchid Dendrobium loddigesii. Although moscatilin has been reported to suppress tumor angiogenesis and growth, the anti-metastatic property of moscatilin has not been elucidated. The present results revealed that moscatilin inhibited metastatic behavior of HCC cells without cytotoxic fashion in highly invasive human HCC cell lines. Furthermore, moscatilin significantly suppressed the activity of urokinase plasminogen activator (uPA), but not matrix metalloproteinase (MMP)-2 and MMP-9. Interestingly, moscatilin-suppressed uPA activity was through down-regulation the protein level of uPA, and did not impair the uPA receptor and uPA inhibitory molecule (PAI-1) expressions. Meanwhile, the mRNA expression of uPA was inhibited via moscatilin in a concentration-dependent manner. In addition, the expression of phosphorylated Akt, rather than ERK1/2, was inhibited by moscatilin treatment. The expression of phosphor-IκBα, and -p65, as well as κB-luciferase activity were also repressed after moscatilin treatment. Transfection of constitutively active Akt (Myr-Akt) obviously restored the moscatilin-inhibited the activation of NF-κB and uPA, and cancer invasion in HCC cells. Taken together, these results suggest that moscatilin impedes HCC invasion and uPA expression through the Akt/NF-κB signaling pathway. Moscatilin might serve as a potential anti-metastatic agent against the disease progression of human HCC.

Visfatin Promotes the Metastatic Potential of Chondrosarcoma Cells by Stimulating AP-1-Dependent MMP-2 Production in the MAPK Pathway.

Chondrosarcoma is a malignant bone tumor that is characterized by high metastatic potential and marked resistance to radiation and chemotherapy. The knowledge that adipokines facilitate the initiation, progression, metastasis, and treatment resistance of various tumors has driven several in vitro and in vivo investigations into the effects of adipokines resistin, leptin, and adiponectin upon the development and progression of chondrosarcomas. Another adipokine, visfatin, is known to regulate tumor progression and metastasis, although how this molecule may affect chondrosarcoma metastasis is unclear. Here, we found that visfatin facilitated cellular migration via matrix metalloproteinase-2 (MMP-2) production in human chondrosarcoma cells and overexpression of visfatin enhanced lung metastasis in a mouse model of chondrosarcoma. Visfatin-induced stimulation of MMP-2 synthesis and activation of the AP-1 transcription factor facilitated chondrosarcoma cell migration via the ERK, p38, and JNK signaling pathways. This evidence suggests that visfatin is worth targeting in the treatment of metastatic chondrosarcoma.

Zoanthamine Alkaloid Derivatives from the Zoantharian Zoanthus vietnamensis with Antimetastatic Activity.

A novel compound zoanone A (1), together with eight new alkaloids, 3ß,14α-dihydroxy-28-deoxyzoanthenamine (2), 7α-hydroxy-28-deoxyzoanthenamine (3), 3α-hydroxyzoanthenamine (4), 7ß-hydroxyzoanthenamine (5), 28α-methoxyzoanthenamine (6), 28α-methoxykuroshine A (7), 30-hydroxykuroshine A (8), and 3ß-hydroxy-11-deketo-kuroshine B (9), was isolated from the zoantharian Zoanthus vietnamensis. Their structures were elucidated by the comprehensive analyses of IR, mass spectrometry, NMR, and UV spectroscopic data. The absolute configuration of 1 was established by single-crystal X-ray crystallographic analysis using Cu Kα radiation. A plausible biosynthetic pathway of 1 was proposed. Antiangiogenic and antilymphangiogenic activities of the isolated metabolites were tested and evaluated. The results showed that all isolated compounds had weak antimetastatic activity.

Aleuritin, a novel dinor-diterpenoid from the twigs of Aleurites moluccanus with an anti-lymphangiogenic effect.

A phytochemical investigation of Aleurites moluccanus yielded one novel dinor-diterpenoid, aleuritin (1), along with a rare diterpenoid, aleuritone (2). Compound 1 has an unprecedented skeleton with a 6/6/5-fused tricyclic ring system. Compound 2 possesses a rare 6/6/5/3-fused tetracyclic skeleton, which is probably an artifact formed photochemically by the Norrish reaction. The structures of 1 and 2 were determined by spectroscopic methods (ECD, IR, mass, and NMR) and confirmed by single-crystal X-ray diffraction analyses. A plausible biogenetic pathway of 1 is proposed. Pharmacological study showed that these two compounds possessed mild in vitro anti-lymphangiogenic activity, which suppressed tube formation with IC50 values of 48.1 ± 1.8 and 34.2 ± 0.8 µg mL-1, respectively.