Impact of establishing a level-1 trauma center for lower extremity trauma: a 4-year experience.

PURPOSE: A multidisciplinary approach is essential for trauma patients' treatment, particularly for cases with open lower extremity fractures, which are considered major traumas requiring a comprehensive approach. Recently, the social demand for severe-trauma centers has increased. This study analyzed the clinical impact of establishing a trauma center for the treatment of open lower extremity fractures. METHODS: A retrospective chart review was conducted for trauma patients admitted to our hospital. Patients were classified into two groups: before (January 2014-December 2015, 178 patients) and after establishment of a Level-1 trauma center (January 2017-December 2018, 125 patients). We included patients with open fracture below the knee level and Gustilo type II/III, but excluded those with life-threatening trauma that affected the treatment choice. RESULTS: Total 273 patient were included in this study, initial infection was significantly more common and external fixator application significantly less in post-center establishment group. The time to emergency operation decreased significantly from 13.89 ± 17.48 to 11.65 ± 19.33 h post-center setup. By multivariate analysis, the decreased primary amputation and increased limb salvage was attributed to establishment of the trauma center. CONCLUSION: With the establishment of the Level-1 trauma center, limbs of patients with open lower extremity fractures could be salvaged, and the need for primary amputation was decreased. Early control of initial open wound infection and minimizing external fixator use allowed early soft tissue reconstruction. The existence of the center ensured a shorter interval to emergency operation and facilitated interdepartmental cooperation, which promoted active limb salvage and contributed to patients' quality of life.

Paraspinal Necrotizing Fasciitis Associated with Pressure Injury: An Unusual Case Report.

ABSTRACT: Necrotizing fasciitis is a type of soft tissue infection that destroys subcutaneous tissue. It is particularly dangerous for patients with chronic diseases and those who are bedridden while recuperating. Although necrotizing fasciitis is often caused by trauma or postoperative infection, in rare cases, it can be attributed to pressure injury (PI). The disease progression is very aggressive and can be lethal for patients who are bedridden or immunocompromised.This case report describes a 47-year-old man with a history of diabetes and hypertension who became bedridden after a sudden status decline caused by nephrotic syndrome. He gradually developed an infection and rare deterioration of a PI on his upper back. After radiologic evaluation with magnetic resonance imaging and computed tomography, surgical intervention was performed and necrotizing fasciitis was confirmed. In this case of necrotizing fasciitis derived from a PI on the upper back, the infected area spread to the periphery at a rapid rate. The infection spread over his back and across the T1-T9 levels.In this report, the authors describe the integrated system of the thoracolumbar fascia and the very aggressive spread of necrotizing fasciitis. Because of the anatomic structure of the back and the characteristics of this infection, only aggressive surgical debridement could prevent the spread of infection and reduce the systemic effects of the infection. Physicians should be aware of the possibility of PIs in bedridden patients and, in cases of exacerbation of the wound, consider rapid surgical intervention after prompt examination and diagnosis to reduce mortality.

Galangin enhances TGF-ß1-mediated growth inhibition by suppressing phosphorylation of threonine 179 residue in Smad3 linker region.

Smad3 linker phosphorylation is a candidate target for several kinases that play important roles in cancer cell initiation, proliferation and progression. Also, Smad3 is an essential intracellular mediator of TGF-ß1-induced transcriptional responses during carcinogenesis. Therefore, it is highly advantageous to identify and develop inhibitors targeting Smad3 linker phosphorylation for the treatment of cancers. Galangin (3,5,7-trihydroxyflavone) has been known to be an active flavonoid showing a cytotoxic effect on several cancer cells. However, the mechanism of action of galangin in various cancers remains unclear, and there has been no report concerning regulation of Smad3 phosphorylation by galangin. In the present study, we show that galangin significantly induced apoptosis and inhibited cell proliferation in the presence of TGF-ß1 in both human prostate and pancreatic cancer cell lines. Particularly, galangin effectively inhibits phosphorylation of the Thr-179 site at Smad3 linker region through suppression of CDK4 phosphorylation. Thus, galangin can be a promising candidate as a selective inhibitor to suppress phosphorylation of Smad3 linker region.

Discovery of indirubin derivatives as new class of DRAK2 inhibitors from high throughput screening.

DRAK2 is a serine/threonine kinase belonging to the death-associated protein kinase (DAPK) family and has emerged as a promising drug target for the treatment of autoimmune diseases and cancers. To identify small molecule inhibitors for DRAK2, we performed a high throughput screening campaign using in-house chemical library and identified indirubin-3'-monoximes as novel class of DRAK2 inhibitors. Among the compounds tested, compound 16 exhibited the most potent inhibitory activity against DRAK2 (IC50=0.003µM). We also propose that compound 16 may bind to the ATP-binding site of the enzyme based on enzyme kinetics and molecular docking studies.

ELK3 Expression Correlates With Cell Migration, Invasion, and Membrane Type 1-Matrix Metalloproteinase Expression in MDA-MB-231 Breast Cancer Cells.

ELK3 is a member of the Ets family of transcription factors. Its expression is associated with angiogenesis, vasculogenesis, and chondrogenesis. ELK3 inhibits endothelial migration and tube formation through the regulation of MT1-MMP transcription. This study assessed the function of ELK3 in breast cancer (BC) cells by comparing its expression between basal and luminal cells in silico and in vitro. In silico analysis showed that ELK3 expression was higher in the more aggressive basal BC cells than in luminal BC cells. Similarly, in vitro analysis showed that ELK3 mRNA and protein expression was higher in basal BC cells than in normal cells and luminal BC cells. To investigate whether ELK3 regulates basal cell migration or invasion, knockdown was achieved by siRNA in the basal BC cell line MDA-MB-231. Inhibition of ELK3 expression decreased cell migration and invasion and downregulated MT1-MMP, the expression of which is positively correlated with tumor cell invasion. In silico analysis revealed that ELK3 expression was associated with that of MT1-MMP in several BC cell lines (0.98 Pearson correlation coefficient). Though MT1-MMP expression was upregulated upon ELK3 nuclear translocation, ELK3 did not directly bind to the 1.3-kb promoter region of the MT1-MMP gene. These results suggest that ELK3 plays a positive role in the metastasis of BC cells by indirectly regulating MT1-MMP expression.

Tm4sf19 deficiency inhibits osteoclast multinucleation and prevents bone loss.

BACKGROUND: Multinucleation is a hallmark of osteoclast formation and has a unique ability to resorb bone matrix. During osteoclast differentiation, the cytoskeleton reorganization results in the generation of actin belts and eventual bone resorption. Tetraspanins are involved in adhesion, migration and fusion in various cells. However, its function in osteoclast is still unclear. In this study, we identified Tm4sf19, a member of the tetraspanin family, as a regulator of osteoclast function. MATERIALS AND METHODS: We investigate the effect of Tm4sf19 deficiency on osteoclast differentiation using bone marrow-derived macrophages obtained from wild type (WT), Tm4sf19 knockout (KO) and Tm4sf19 LELΔ mice lacking the large extracellular loop (LEL). We analyzed bone mass of young and aged WT, KO and LELΔ mice by µCT analysis. The effects of Tm4sf19 LEL-Fc fusion protein were accessed in osteoclast differentiation and osteoporosis animal model. RESULTS: We found that deficiency of Tm4sf19 inhibited osteoclast function and LEL of Tm4sf19 was responsible for its function in osteoclasts in vitro. KO and LELΔ mice exhibited higher trabecular bone mass compared to WT mice. We found that Tm4sf19 interacts with integrin αvß3 through LEL, and that this binding is important for cytoskeletal rearrangements in osteoclast by regulating signaling downstream of integrin αvß3. Treatment with LEL-Fc fusion protein inhibited osteoclast function in vitro and administration of LEL-Fc prevented bone loss in an osteoporosis mouse model in vivo. CONCLUSION: We suggest that Tm4sf19 regulates osteoclast function and that LEL-Fc may be a promising drug to target bone destructive diseases caused by osteoclast hyper-differentiation.

Effect of aging on the formation and growth of colonic epithelial organoids by changes in cell cycle arrest through TGF-ß-Smad3 signaling.

BACKGROUND: This study aimed to investigate how aging alters the homeostasis of the colonic intestinal epithelium and regeneration after tissue injury using organoid models and to identify its underlying molecular mechanism. METHODS: To investigate aging-related changes in the colonic intestinal epithelium, we conducted organoid cultures from old (older than 80 weeks) and young (6-10 weeks) mice and compared the number and size of organoids at day 5 of passage 0 and the growth rate of organoids between the two groups. RESULTS: The number and size of organoids from old mice was significantly lower than that from young mice (p < 0.0001) at day 5 of passage 0. The growth rate of old-mouse organoids from day 4 to 5 of passage 0 was significantly slower than that of young-mouse organoids (2.21 times vs. 1.16 times, p < 0.001). RNA sequencing showed that TGF-ß- and cell cycle-associated genes were associated with the aging effect. With regard to mRNA and protein levels, Smad3 and p-Smad3 in the old-mouse organoids were markedly increased compared with those in the young-mouse organoids. Decreased expression of ID1, increased expression of p16INK4a, and increased cell cycle arrest were observed in the old mouse-organoids. Treatment with SB431542, a type I TGF-ß receptor inhibitor, significantly increased the formation and growth of old-mouse organoids, and TGF-ß1 treatment markedly suppressed the formation of young-mouse organoids. In the acute dextran sulfate sodium-colitis model and its organoid experiments, the colonic epithelial regeneration after tissue injury in old mice was significantly decreased compared with young mice. CONCLUSIONS: Aging reduced the formation ability and growth rate of colonic epithelial organoids by increasing cell cycle arrest through TGF-ß-Smad3-p16INK4a signaling.

Peli3 ablation ameliorates acetaminophen-induced liver injury through inhibition of GSK3ß phosphorylation and mitochondrial translocation.

The signaling pathways governing acetaminophen (APAP)-induced liver injury have been extensively studied. However, little is known about the ubiquitin-modifying enzymes needed for the regulation of APAP-induced liver injury. Here, we examined whether the Pellino3 protein, which has E3 ligase activity, is needed for APAP-induced liver injury and subsequently explored its molecular mechanism. Whole-body Peli3-/- knockout (KO) and adenovirus-mediated Peli3 knockdown (KD) mice showed reduced levels of centrilobular cell death, infiltration of immune cells, and biomarkers of liver injury, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), upon APAP treatment compared to wild-type (WT) mice. Peli3 deficiency in primary hepatocytes decreased mitochondrial and lysosomal damage and reduced the mitochondrial reactive oxygen species (ROS) levels. In addition, the levels of phosphorylation at serine 9 in the cytoplasm and mitochondrial translocation of GSK3ß were decreased in primary hepatocytes obtained from Peli3-/- KO mice, and these reductions were accompanied by decreases in JNK phosphorylation and mitochondrial translocation. Pellino3 bound more strongly to GSK3ß compared with JNK1 and JNK2 and induced the lysine 63 (K63)-mediated polyubiquitination of GSK3ß. In rescue experiments, the ectopic expression of wild-type Pellino3 in Peli3-/- KO hepatocytes restored the mitochondrial translocation of GSK3ß, but this restoration was not obtained with expression of a catalytically inactive mutant of Pellino3. These findings are the first to suggest a mechanistic link between Pellino3 and APAP-induced liver injury through the modulation of GSK3ß polyubiquitination.

Degradation of DRAK1 by CUL3/SPOP E3 Ubiquitin ligase promotes tumor growth of paclitaxel-resistant cervical cancer cells.

Despite favorable responses to initial chemotherapy, drug resistance is a major cause limiting chemotherapeutic efficacy in many advanced cancers. However, mechanisms that drive drug-specific resistance in chemotherapy for patients with advanced cancers are still unclear. Here, we report a unique role of death-associated protein kinase-related apoptosis-inducing kinase 1 (DRAK1) associated with paclitaxel resistance in cervical cancer cells. Interestingly, DRAK1 protein level was markedly decreased in paclitaxel-resistant cervical cancer cells without affecting its mRNA expression, which resulted in an increase in tumor necrosis factor receptor-associated factor 6 (TRAF6) expression, as well as an activation of TRAF6-mediated nuclear factor-kappa B (NF-κB) signaling cascade, thereby promoting tumor progression. DRAK1 depletion markedly increased the chemotherapeutic IC50 values of paclitaxel in cervical cancer cells. Ectopic expression of DRAK1 inhibited growth of paclitaxel-resistant cervical cancer cells in vitro and in vivo. Furthermore, DRAK1 was markedly underexpressed in chemoresistant cervical cancer patient tissues compared with chemosensitive samples. We found that DRAK1 protein was destabilized through K48-linked polyubiquitination promoted by the Cullin scaffold protein 3 (CUL3) / speckle-type POZ (poxvirus and zinc finger protein) protein (SPOP) E3 ubiquitin ligase in paclitaxel-resistant cells. Collectively, these findings suggest that DRAK1 may serve as a potential predictive biomarker for overcoming paclitaxel resistance in cervical cancer.

ESRP1-regulated isoform switching of LRRFIP2 determines metastasis of gastric cancer.

Although accumulating evidence indicates that alternative splicing is aberrantly altered in many cancers, the functional mechanism remains to be elucidated. Here, we show that epithelial and mesenchymal isoform switches of leucine-rich repeat Fli-I-interacting protein 2 (LRRFIP2) regulated by epithelial splicing regulatory protein 1 (ESRP1) correlate with metastatic potential of gastric cancer cells. We found that expression of the splicing variants of LRRFIP2 was closely correlated with that of ESRP1. Surprisingly, ectopic expression of the mesenchymal isoform of LRRFIP2 (variant 3) dramatically increased liver metastasis of gastric cancer cells, whereas deletion of exon 7 of LRRFIP2 by the CRISPR/Cas9 system caused an isoform switch, leading to marked suppression of liver metastasis. Mechanistically, the epithelial LRRFIP2 isoform (variant 2) inhibited the oncogenic function of coactivator-associated arginine methyltransferase 1 (CARM1) through interaction. Taken together, our data reveals a mechanism of LRRFIP2 isoform switches in gastric cancer with important implication for cancer metastasis.

Therapeutic Implications of TGF-ß Pathway in Desmoid Tumor Based on Comprehensive Molecular Profiling and Clinicopathological Properties.

(1) Background: Desmoid tumors have a relatively high local failure rate after primary treatment using surgery and/or radiotherapy. Moreover, desmoid tumors recur at the primary site for many patients. An effective therapeutic strategy for the desmoid tumor is needed to maintain quality of life and prolong survival. (2) Method: First of all, we collected desmoid tumor tissues and investigated the status of protein expression for beta-catenin and alpha-SMA through immunohistochemistry. Then, we performed targeted sequencing and whole RNA sequencing. To compare the data with other cancer types, we used NGS data from sarcoma patients at Yonsei Cancer Center (YCC-sarcoma cohort, n = 48) and The Cancer Genome Atlas (TCGA, n = 9235). Secondly, we established the novel patient-derived preclinical models (n = 2) for the validation of treatment strategy. The same gene alteration of primary tissue was demonstrated. (3) Results: We discovered specific gene sets related to the TGF-ß signaling pathway. Moreover, we selected the combination treatment comprising TGF-ß inhibitor, vactosertib, and imatinib. In screening for the anti-proliferation effect, the combination treatment of TGF-ß inhibitor was more effective for tumor suppression than monotherapy. (4) Conclusion: We found preclinical indications that TGF-ß inhibitors could prove useful as a potential treatment for patients with desmoid tumors. Moreover, we could find some examples in clinical trials.

Mast4 determines the cell fate of MSCs for bone and cartilage development.

Mesenchymal stromal cells (MSCs) differentiation into different lineages is precisely controlled by signaling pathways. Given that protein kinases play a crucial role in signal transduction, here we show that Microtubule Associated Serine/Threonine Kinase Family Member 4 (Mast4) serves as an important mediator of TGF-ß and Wnt signal transduction in regulating chondro-osteogenic differentiation of MSCs. Suppression of Mast4 by TGF-ß1 led to increased Sox9 stability by blocking Mast4-induced Sox9 serine 494 phosphorylation and subsequent proteasomal degradation, ultimately enhancing chondrogenesis of MSCs. On the other hand, Mast4 protein, which stability was enhanced by Wnt-mediated inhibition of GSK-3ß and subsequent Smurf1 recruitment, promoted ß-catenin nuclear localization and Runx2 activity, increasing osteogenesis of MSCs. Consistently, Mast4-/- mice demonstrated excessive cartilage synthesis, while exhibiting osteoporotic phenotype. Interestingly, Mast4 depletion in MSCs facilitated cartilage formation and regeneration in vivo. Altogether, our findings uncover essential roles of Mast4 in determining the fate of MSC development into cartilage or bone.

Phytochemicals in Cancer Immune Checkpoint Inhibitor Therapy.

The interaction of immune checkpoint molecules in the tumor microenvironment reduces the anti-tumor immune response by suppressing the recognition of T cells to tumor cells. Immune checkpoint inhibitor (ICI) therapy is emerging as a promising therapeutic option for cancer treatment. However, modulating the immune system with ICIs still faces obstacles with severe immunogenic side effects and a lack of response against many cancer types. Plant-derived natural compounds offer regulation on various signaling cascades and have been applied for the treatment of multiple diseases, including cancer. Accumulated evidence provides the possibility of efficacy of phytochemicals in combinational with other therapeutic agents of ICIs, effectively modulating immune checkpoint-related signaling molecules. Recently, several phytochemicals have been reported to show the modulatory effects of immune checkpoints in various cancers in in vivo or in vitro models. This review summarizes druggable immune checkpoints and their regulatory factors. In addition, phytochemicals that are capable of suppressing PD-1/PD-L1 binding, the best-studied target of ICI therapy, were comprehensively summarized and classified according to chemical structure subgroups. It may help extend further research on phytochemicals as candidates of combinational adjuvants. Future clinical trials may validate the synergetic effects of preclinically investigated phytochemicals with ICI therapy.

Metastasis Risk Assessment Using BAG2 Expression by Cancer-Associated Fibroblast and Tumor Cells in Patients with Breast Cancer.

Few studies have examined the role of BAG2 in malignancies. We investigated the prognostic value of BAG2-expression in cancer-associated fibroblasts (CAFs) and tumor cells in predicting metastasis-free survival in patients with breast cancer. Tissue-microarray was constructed using human breast cancer tissues obtained by surgical resection between 1992 and 2015. BAG2 expression was evaluated by immunohistochemistry in CAFs or the tumor cells. BAG2 expression in the CAFs and cytoplasm of tumor cells was classified as positive and negative, and low and high, respectively. BAG2-CAF was evaluated in 310 patients and was positive in 67 (21.6%) patients. Kaplan-Meier plots showed that distant metastasis-free survival (DMFS) was lesser in patients with BAG2(+) CAF than in patients with BAG2(-) CAF (p = 0.039). Additionally, we classified the 310 patients into two groups: 109 in either BAG2-high or BAG2(+) CAF and 201 in BAG2-low and BAG2(-) CAF. DMFS was significantly reduced in patients with either BAG2-high or BAG2(+) CAF than in the patients of the other group (p = 0.005). Multivariable analysis demonstrated that DMFS was prolonged in patients with BAG2(-) CAF or BAG2-low. Evaluation of BAG2 expression on both CAFs and tumor cells could help in determining the risk of metastasis in breast cancer.

Tetraarsenic hexoxide enhances generation of mitochondrial ROS to promote pyroptosis by inducing the activation of caspase-3/GSDME in triple-negative breast cancer cells.

Although tetraarsenic hexoxide is known to exert an anti-tumor effect by inducing apoptosis in various cancer cells, its effect on other forms of regulated cell death remains unclear. Here, we show that tetraarsenic hexoxide induces the pyroptotic cell death through activation of mitochondrial reactive oxygen species (ROS)-mediated caspase-3/gasdermin E (GSDME) pathway, thereby suppressing tumor growth and metastasis of triple-negative breast cancer (TNBC) cells. Interestingly, tetraarsenic hexoxide-treated TNBC cells exhibited specific pyroptotic characteristics, including cell swelling, balloon-like bubbling, and LDH releases through pore formation in the plasma membrane, eventually suppressing tumor formation and lung metastasis of TNBC cells. Mechanistically, tetraarsenic hexoxide markedly enhanced the production of mitochondrial ROS by inhibiting phosphorylation of mitochondrial STAT3, subsequently inducing caspase-3-dependent cleavage of GSDME, which consequently promoted pyroptotic cell death in TNBC cells. Collectively, our findings highlight tetraarsenic hexoxide-induced pyroptosis as a new therapeutic strategy that may inhibit cancer progression of TNBC cells.

In Vitro Analysis of Histology, Mechanics, and Safety of Radiation-free Pre-hydrated Human Acellular Dermal Matrix.

PURPOSE: Acellular dermal matrix (ADM) supports tissue expanders or implants in implant-based breast reconstruction. The characteristics of ADM tissue are defined by the manufacturing procedure, such as decellularization, preservation, and sterilization, and are directly related to clinical outcomes. This study aimed to compare the properties of a new pre-hydrated-ADM (H-ADM-low) obtained using a decellularization reagent reduction process with a low concentration of detergent with those of radiation-sterilized H-ADM and freeze-dried ADM (FD-ADM). METHODS: ADMs were evaluated in terms of structure, mechanical quality, and cytotoxicity using histochemical staining, tensile strength testing, and in vitro cell viability analysis. RESULTS: The tissue structure of H-ADM-low (CGDERM ONE-STEP) was similar to that of native skin despite complete decellularization. By contrast, in FD-ADM, the tissue structure was damaged by the freeze-drying process, and radiation-sterilized H-ADM showed a compact fibrillar arrangement. Furthermore, matrix components such as collagen and elastin were preserved in H-ADM-low, whereas a loss of elastin fibers with fragmented distribution was observed in radiation-sterilized H-ADMs. H-ADM-low's tensile strength (58.84 MPa) was significantly greater than that of FD-ADM (38.60 MPa) and comparable with that of radiation-sterilized H-ADMs. The residual detergent content in H-ADM-low (47.45 mg/L) was 2.67-fold lower than that of H-ADM decellularized with a conventional detergent concentration (126.99 mg/mL), and this finding was consistent with the cell viability results (90.7% and 70.7%, respectively), indicating that H-ADM-low has very low cytotoxicity. CONCLUSIONS: H-ADM-low produced through aseptic processes retains the original tissue structure, demonstrates excellent mechanical properties, and does not affect cell viability. Therefore, this newer H-ADM is suitable for use in implant-based breast reconstruction.

The lysophospholipase D enzyme Gdpd3 is required to maintain chronic myelogenous leukaemia stem cells.

Although advanced lipidomics technology facilitates quantitation of intracellular lipid components, little is known about the regulation of lipid metabolism in cancer cells. Here, we show that disruption of the Gdpd3 gene encoding a lysophospholipase D enzyme significantly decreased self-renewal capacity in murine chronic myelogenous leukaemia (CML) stem cells in vivo. Sophisticated lipidomics analyses revealed that Gdpd3 deficiency reduced levels of certain lysophosphatidic acids (LPAs) and lipid mediators in CML cells. Loss of Gdpd3 also activated AKT/mTORC1 signalling and cell cycle progression while suppressing Foxo3a/ß-catenin interaction within CML stem cell nuclei. Strikingly, CML stem cells carrying a hypomorphic mutation of Lgr4/Gpr48, which encodes a leucine-rich repeat (LRR)-containing G-protein coupled receptor (GPCR) acting downstream of Gdpd3, displayed inadequate disease-initiating capacity in vivo. Our data showing that lysophospholipid metabolism is required for CML stem cell maintenance in vivo establish a new, biologically significant mechanism of cancer recurrence that is independent of oncogene addiction.

ROS-Induced SIRT2 Upregulation Contributes to Cisplatin Sensitivity in Ovarian Cancer.

Cisplatin resistance remains a significant obstacle for improving the clinical outcome of ovarian cancer patients. Recent studies have demonstrated that cisplatin is an important inducer of intracellullar reactive oxygen species (ROS), triggering cancer cell death. Sirtuin 2 (SIRT2), a member of class III NAD+ dependent histone deacetylases (HDACs), has been reported to be involved in regulating cancer hallmarks including drug response. In this study, we aimed to identify the role of SIRT2 in oxidative stress and cisplatin response in cancer. Two ovarian cancer cell lines featuring different sensitivities to cisplatin were used in this study. We found different expression patterns of SIRT2 in cisplatin-sensitive (A2780/S) and cisplatin-resistant (A2780/CP) cancer cells with cisplatin treatment, where SIRT2 expression was augmented only in A2780/S cells. Furthermore, cisplatin-induced ROS generation was responsible for the upregulation of SIRT2 in A2780/S cells, whereas overexpression of SIRT2 significantly enhanced the sensitivity of cisplatin-resistant counterpart cells to cisplatin. Our study proposes that targeting SIRT2 may provide new strategies to potentiate platinum-based chemotherapy in ovarian cancer patients.

Destablilization of TRAF6 by DRAK1 Suppresses Tumor Growth and Metastasis in Cervical Cancer Cells.

The adaptor protein TNF receptor-associated factor 6 (TRAF6) is a key mediator in inflammation. However, the molecular mechanisms controlling its activity and stability in cancer progression remain unclear. Here we show that death-associated protein kinase-related apoptosis-inducing kinase 1 (DRAK1) inhibits the proinflammatory signaling pathway by targeting TRAF6 for degradation, thereby suppressing inflammatory signaling-mediated tumor growth and metastasis in advanced cervical cancer cells. DRAK1 bound directly to the TRAF domain of TRAF6, preventing its autoubiquitination by interfering with homo-oligomerization, eventually leading to autophagy-mediated degradation of TRAF6. Depletion of DRAK1 in cervical cancer cells resulted in markedly increased levels of TRAF6 protein, promoting activation of the IL1ß signaling-associated pathway and proinflammatory cytokine production. DRAK1 was specifically underexpressed in metastatic cervical cancers and inversely correlated with TRAF6 expression in mouse xenograft model tumor tissues and human cervical tumor tissues. Collectively, our findings highlight DRAK1 as a novel antagonist of inflammation targeting TRAF6 for degradation that limits inflammatory signaling-mediated progression of advanced cervical cancer. SIGNIFICANCE: Serine/threonine kinase DRAK1 serves a unique role as a novel negative regulator of the inflammatory signaling mediator TRAF6 in cervical cancer progression.

Capsaicin induces apoptosis by generating reactive oxygen species and disrupting mitochondrial transmembrane potential in human colon cancer cell lines.

Although genetic factors are a well-known cause of colorectal cancer, environmental factors contribute more to its development. Despite advances in the fields of surgery, radiotherapy and chemotherapy, the cure rates for colon cancer have not substantially improved over the past few decades. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), the principal pungent ingredient of hot chili pepper, has exhibited an anti-tumor effect in many cell types. However, the mechanisms responsible for the anti-tumor effect of capsaicin are not yet completely understood. In this study, we investigated whether capsaicin induces apoptosis in colon cancer cell lines. Capsaicin decreased cell viability in a dose-dependent manner in Colo320DM and LoVo cells. In addition, capsaicin produced cell morphology changes and DNA fragmentation, decreased the DNA contents, and induced phosphatidylserine translocation, which is a hallmark of apoptotic cell death. We showed that capsaicin-induced apoptosis is associated with an increase in ROS generation and a disruption of the mitochondrial transmenbrane potential. A possible mechanism of capsaicin-induced apoptosis is the activation of caspase 3, a major apoptosis-executing enzyme. Treatment with capsaicin induced a dramatic increase in caspase 3 activity, as assessed by the cleavage of Ac-DEVD-AMC, a fluorogenic substrate. In conclusion, our results clearly showed that capsaicin induced apoptosis in colon cancer cells. Although the actual mechanisms of capsaicin-induced apoptosis remain uncertain, it may be a beneficial agent for colon cancer treatment and chemoprevention.