Comparison of procedural outcomes between morning and afternoon colonoscopies performed by colorectal surgeons.

BACKGROUND AND OBJECTIVE: Colonoscopy is a common procedure performed by colorectal surgeons for screening, diagnosis, and surveillance of various colorectal diseases. Existing literature has conflicting data on quality outcomes of colonoscopies performed in the afternoon and the morning schedules and only includes colonoscopies performed by gastroenterologists. We sought to analyze procedural outcomes between morning and afternoon colonoscopies performed by colorectal surgeons. DATA SOURCES AND MAIN OUTCOME MEASURES: A retrospective chart review of colonoscopies performed by colorectal surgeons at a tertiary care center from October 2018 through July 2020 was performed. Complete colonoscopies with documented times were included. Patients with colonic resection and incomplete colonoscopy were excluded. Main outcome measures adenoma and polyp detection rates and colonoscopy time variables were compared between morning and afternoon colonoscopies. RESULTS: A total of 781 patients were analyzed. Colonoscopies were evenly distributed during shifts (49% morning and 51% afternoon). The overall polyp and adenoma detection rates were 46% and 29%, respectively. There were no significant differences in adenoma and polyp detection rates and colonoscopy duration between morning and afternoon colonoscopies. Multivariate analysis demonstrated that history of prior polypectomy was an independent predictor of adenoma detection rate (OR: 2.17, 95% CI 1.33-3.54, p = 0.002) and was associated with significantly increased colonoscopy times in afternoon shift. CONCLUSION: There were no differences in quality outcomes of adenoma and polyp detection rates between morning and afternoon colonoscopies performed by colorectal surgeons. In addition to known predictors, cecal intubation time and history of polypectomy were also independent predictors of adenoma detection rate. Patients with prior polypectomy had increased colonoscopy times in afternoon shift. Since colorectal surgeons perform higher proportion of diagnostic and surveillance colonoscopies, these patients may be better suited for colonoscopies in morning shift.

NFκB in Pancreatic Stellate Cells Reduces Infiltration of Tumors by Cytotoxic T Cells and Killing of Cancer Cells, via Up-regulation of CXCL12.

BACKGROUND & AIMS: Immunotherapies are ineffective against pancreatic cancer. We investigated whether the activity of nuclear factor (NF)κB in pancreatic stromal cells contributes to an environment that suppresses antitumor immune response. METHODS: Pancreata of C57BL/6 or Rag1-/- mice were given pancreatic injections of a combination of KrasG12D/+; Trp53 R172H/+; Pdx-1cre (KPC) pancreatic cancer cells and pancreatic stellate cells (PSCs) extracted from C57BL/6 (control) or mice with disruption of the gene encoding the NFκB p50 subunit (Nfkb1 or p50-/- mice). Tumor growth was measured as an endpoint. Other mice were given injections of Lewis lung carcinoma (LLC) lung cancer cells or B16-F10 melanoma cells with control or p50-/- fibroblasts. Cytotoxic T cells were depleted from C57BL/6 mice by administration of antibodies against CD8 (anti-CD8), and growth of tumors from KPC cells, with or without control or p50-/- PSCs, was measured. Some mice were given an inhibitor of CXCL12 (AMD3100) and tumor growth was measured. T-cell migration toward cancer cells was measured using the Boyden chamber assay. RESULTS: C57BL/6 mice coinjected with KPC cells (or LLC or B16-F10 cells) and p50-/- PSCs developed smaller tumors than mice given injections of the cancer cells along with control PSCs. Tumors that formed when KPC cells were injected along with p50-/- PSCs had increased infiltration by activated cytotoxic T cells along with decreased levels of CXCL12, compared with tumors grown from KPC cells injected along with control PSCs. KPC cells, when coinjected with control or p50-/- PSCs, developed the same-size tumors when CD8+ T cells were depleted from C57BL/6 mice or in Rag1-/- mice. The CXCL12 inhibitor slowed tumor growth and increased tumor infiltration by cytotoxic T cells. In vitro expression of p50 by PSCs reduced T-cell migration toward and killing of cancer cells. When cultured with cancer cells, control PSCs expressed 10-fold higher levels of CXCL12 than p50-/- PSCs. The CXCL12 inhibitor increased migration of T cells toward KPC cells in culture. CONCLUSIONS: In studies of mice and cell lines, we found that NFκB activity in PSCs promotes tumor growth by increasing expression of CXCL12, which prevents cytotoxic T cells from infiltrating the tumor and killing cancer cells. Strategies to block CXCL12 in pancreatic tumor cells might increase antitumor immunity.

Correction to: Pre-clinical evaluation of Minnelide as a therapy for acute myeloid leukemia.

Following publication of the original article [1], the authors found an error in Figure 3. The middle panel of Figure 3a was inadvertently duplicated.

Pre-clinical evaluation of Minnelide as a therapy for acute myeloid leukemia.

BACKGROUND: There is an urgent need for novel and effective treatment options for acute myeloid leukemia (AML). Triptolide, a diterpenoid tri-epoxide compound isolated from the herb Tripterygium wilfordii and its water-soluble pro-drug-Minnelide have shown promising anti-cancer activity. A recent clinical trial for patients with solid tumors confirmed the safety and efficacy at biologically equivalent doses of 0.2 mg/kg/day and lower. METHODS: Cell viability of multiple AML cell lines as well as patient apheresis samples were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) based assay. Apoptosis was evaluated by estimating the amount of cleaved caspase. AML cell line (THP1-Luc) was implanted in immunocompromised mice and treated with indicated doses of Minnelide. Leukemic burden before and after treatment was evaluated by imaging in an In Vivo Imaging System (IVIS). RESULTS: In the current study, we show that Minnelide, at doses below maximum tolerated dose (MTD) demonstrates leukemic clearance of both primary AML blasts and luciferase expressing THP-1 cells in mice. In vitro, multiple primary AML apheresis samples and AML cell lines (THP-1, KG1, Kasumi-1, HL-60) were sensitive to triptolide mediated cell death and apoptosis in low doses. Treatment with triptolide led to a significant decrease in the colony forming ability of AML cell lines as well as in the expression of stem cell markers. Additionally, it resulted in the cell cycle arrest in the G1/S phase with significant downregulation of c-Myc, a major transcriptional regulator mediating cancer cell growth and stemness. CONCLUSION: Our results suggest that Minnelide, with confirmed safety and activity in the clinic, exerts a potent anti-leukemic effect in multiple models of AML at doses easily achievable in patients.

Regulation of angiogenesis by microRNAs in cardiovascular diseases.

Non-coding RNAs are functional RNA molecules comprising the majority of human transcriptome. Only about 1.5% of the human genome is transcribed into messenger RNAs (mRNA) that are translated into proteins. Among the non-coding RNAs, miRNAs are extensively studied and miR targets in endothelial cells, perivascular cells, and angiogenic signaling are relatively well defined. MicroRNAs not only regulate transcripts in situ but also function as paracrine mediators in affecting angiogenesis at distant sites. Exosomal miRs are implicated in modulating endothelial cell function and angiogenesis. Thus miRs have been shown to affect tissue microenvironment in a multitude of ways. A comprehensive analysis of the role of miRs in modulation of angiogenesis and their impact on cardiovascular diseases is presented in this review.

Minnelide Inhibits Androgen Dependent, Castration Resistant Prostate Cancer Growth by Decreasing Expression of Androgen Receptor Full Length and Splice Variants.

BACKGROUND: With almost 30,000 deaths per year, prostate cancer is the second-leading cause of cancer-related death in men. Androgen Deprivation Therapy (ADT) has been the corner stone of prostate cancer treatment for decades. However, despite an initial response of prostate cancer to ADT, this eventually fails and the tumors recur, resulting in Castration Resistant Prostate Cancer (CRPC). Triptolide, a diterpene triepoxide, has been tested for its anti-tumor properties in a number of cancers for over a decade. Owing to its poor solubility in aqueous medium, its clinical application had been limited. To circumvent this problem, we have synthesized a water-soluble pro-drug of triptolide, Minnelide, that is currently being evaluated in a Phase 1 clinical trial against gastrointestinal tumors. In the current study, we assessed the therapeutic potential of Minnelide and its active compound triptolide against androgen dependent prostate cancer both in vitro as well as in vivo. METHODS: Cell viability was measured by a MTT based assay after treating prostate cancer cells with multiple doses of triptolide. Apoptotic cell death was measured using a caspase 3/7 activity. Androgen Receptor (AR) promoter-binding activity was evaluated by using luciferase reporter assay. For evaluating the effect in vivo, 22Rv1 cells were implanted subcutaneously in animals, following which, treatment was started with 0.21 mg/kg Minnelide. RESULTS: Our study showed that treatment with triptolide induced apoptotic cell death in CRPC cells. Triptolide treatment inhibited AR transcriptional activity and decreased the expression of AR and its splice variants both at the mRNA and the protein level. Our studies show that triptolide inhibits nuclear translocation of Sp1, resulting in its decreased transcriptional activity leading to downregulation of AR and its splice variants in prostate cancer cells. In vivo, Minnelide (0.21 mg/kg) regressed subcutaneous tumors derived from CRPC 22RV1 at our study endpoint. Our animal studies further confirmed that Minnelide was more efficacious than the standard of care therapies, Docetaxel and Enzalutamide. CONCLUSION: Our study indicates that Minnelide is very effective as a therapeutic option against CRPC at a dose that is currently tolerated by patients in the ongoing clinical trials. Prostate 77: 584-596, 2017. © 2017 Wiley Periodicals, Inc.

"Heat shock protein 70 in pancreatic diseases: Friend or foe".

The heat shock response in pancreatitis that is activated via HSP70 protects acinar cells through multiple simultaneous mechanisms. It inhibits trypsinogen activation and modulates NF-κB signaling to limit acinar cell injury. On the other hand, HSP70 is overexpressed in pancreatic cancer and is hijacked by the cellular machinery to inhibit apoptosis. Inhibition of HSP70 in pancreatic cancer by a novel compound, Minnelide, has shown considerable clinical promise.

Control of Apoptosis in Treatment and Biology of Pancreatic Cancer.

Pancreatic cancer is estimated to be the 12th most common cancer in the United States in 2014 and yet this malignancy is the fourth leading cause of cancer-related death in the United States. Late detection and resistance to therapy are the major causes for its dismal prognosis. Apoptosis is an actively orchestrated cell death mechanism that serves to maintain tissue homoeostasis. Cancer develops from normal cells by accruing significant changes through one or more mechanisms, leading to DNA damage and mutations, which in a normal cell would induce this programmed cell death pathway. As a result, evasion of apoptosis is one of the hallmarks of cancer cells. PDAC is notoriously resistant to apoptosis, thereby explaining its aggressive nature and resistance to conventional treatment modalities. The current review is focus on understanding different intrinsic and extrinsic pathways in pancreatic cancer that may affect apoptosis in this disease.

Laparoscopic sleeve gastrectomy leads to reduction in thyroxine requirement in morbidly obese patients with hypothyroidism.

BACKGROUND: The impact of laparoscopic sleeve gastrectomy (LSG) on various co-morbidities including type II diabetes mellitus, hypertension, and sleep apnea is well established. However, its effect on hypothyroidism has not been given due attention evidenced by the scant literature on the subject. The purpose of this report is to assess the change in thyroxine (T4) requirement in morbidly obese patients with clinical hypothyroidism after LSG. METHODS: We conducted a retrospective review of morbidly obese patients on T4 replacement therapy for clinical hypothyroidism who underwent LSG from August 2009 to July 2012 at our institution. RESULTS: Of the 200 patients who underwent LSG during this period, 21 (10.5 %) were on T4 replacement therapy preoperatively for clinical hypothyroidism. Two patients were lost to follow-up. The remaining 19 patients were categorized into two groups. Group 1 comprised 13 patients with decreased T4 requirements after LSG. Group 2 comprised six patients in whom the T4 dose remained unaltered. The mean change in T4 requirement in group 1 was 42.07 % (12-100 %). Group 1 patients had a significantly higher mean preoperative body mass index (48.7 vs. 43.0 kg/m(2); p = 0.03) than the group 2 patients. There was a significant correlation between the percentage excess weight loss and the percentage change in T4 requirement in group 1 (r = 0.607, p = 0.028). CONCLUSIONS: Sleeve gastrectomy has a favorable impact on hypothyroid status as seen by a reduction in T4 requirement in the majority of morbidly obese patients with overt hypothyroidism.

Flange Fracture and Dislocation: An Unusual Complication of Percutaneous Tracheostomy.

Percutaneous dilational tracheostomy (PDT) is a commonly used technique in intensive care units (ICUs) for persistent respiratory failure. Early complications of placement includeairway loss, bleeding, and tracheal ring fracture. Tracheostomy tube fracture is a rarely reported complication that can lead to loss of airway and require emergent intervention. We present two case reports of tracheostomy flange fracture and dislocation after PDT. Shortly after insertion, the tracheostomy flange was incidentally noted to have irreparably fractured and separated from the outer cannula. Both patients were orotracheally intubated and converted to open revisional surgical tracheostomy. Outer cannula separation from the flange is a rare but important complication of PDT due to the risk of occult airway loss. The tracheostomy tube supplied in the PDT set is manufactured in three parts and the plastic outer cannula is snapped to the silicone flange during manufacturing. The flange is not meant to be separated during insertion or use. PDT insertion requires significant force to be exerted, as the catheter has to travel through the subcutaneous tissue of the neck before entering the trachea. These cases suggest that the junction of the flange and the outer cannula may be a weak point and that fracture and dislocation at that site may occur due to excessive or misdirected force. Dislocation may cause loss of airway and a need for orotracheal intubation as performed in our cases. Understanding this complication and carefully examining the flange after placement is essential for early recognition to avoid loss of airway.

Minnelide synergizes with conventional chemotherapy by targeting both cancer and associated stroma components in pancreatic cancer.

Addition of nab-paclitaxel to gemcitabine offers a survival benefit of only 6 weeks over gemcitabine alone at a cost of increased toxicity in PDAC. The goal of the present study is to evaluate the efficacy of Minnelide, a water-soluble prodrug of triptolide, in combination with the standard of care regimen for chemotherapy with the added advantage of reducing the doses of these drugs to minimize toxicity. Pancreatic cancer cell lines were implanted subcutaneously or orthotopically in athymic nude or C57BL/6J mice. Subsequently, animals were randomized and received saline or minnelide or full dose chemotherapy or low dose chemotherapy or minnelide in combination with low dose chemotherapy. Our results show that a combination of low doses of Minnelide with Gemcitabine + nab-paclitaxel significantly inhibited tumor progression and increased the survival of tumor-bearing mice in comparison with conventional chemotherapy alone. Moreover, combination therapy significantly reduced cancer-related morbidity by decreasing ascites and metastasis and effectively targeted both cancer and the associated stroma. In vitro studies with a combination of low doses of triptolide and paclitaxel significantly decreased the cell viability, increased apoptosis and led to significantly increased M-phase cell cycle arrest in various pancreatic cancer cell lines as compared to either drug alone. Our results show that Minnelide synergizes with conventional chemotherapy leading to a significant reduction in the doses of these toxic drugs, all the while achieving better efficacy in the treatment of PDAC. This combination effectively targeted both the cancer and the associated stromal components of pancreatic cancer.

An Immunocompetent Model of Pancreatic Cancer Resection and Recurrence.

BACKGROUND: Even after surgical resection, most patients with localized pancreatic ductal adenocarcinoma (PDAC) succumb to disease recurrence. Current animal models do not recapitulate this pattern of disease recurrence. Our goal was to develop a clinically relevant, immunocompetent model of PDAC resection to study recurrence and evaluate therapy. METHODS: Pancreatic cancer cells derived from tumors arising in KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) mice were co-injected with stromal cells (pancreatic stellate cells) into the pancreas of immunocompetent mice to simulate the stroma-rich tumors seen in human PDAC. After allowing tumors to form, we resected these localized tumors and followed the mice for tumor recurrence. Circulating tumor cells (CTCs) were isolated, and systemic chemotherapy or immunotherapy was administered following tumor resection. RESULTS: Tumors formed by co-injection of KPC cells and stromal cells demonstrated a dense desmoplastic reaction similar to that seen in human disease. Resection at days 15 and 21 after implantation revealed uniform tumor volumes of 92 ± 19 mm3 on day 15 and 444 ± 54 mm3 on day 21. Histology of resected tumors showed negative margins. Resembling human PDAC, mice that underwent resection showed improved median survival (58 vs 47 days) but most animals developed intra-abdominal recurrence on follow-up. Adjuvant chemotherapy (median survival 69 vs 58 days), but not immunotherapy (median survival 69 vs 65 days) tended towards improved survival as seen in human disease. Circulating tumor cells were reliably identified from mice with and without resection, suggesting utility of this model in studying tumor metastases and recurrence. CONCLUSION: We describe an immunocompetent animal model that recapitulates human disease in morphology and recurrence patterns. We show that it can be used to evaluate therapy in clinical scenarios associated with surgical resection and may help characterize factors responsible for disease recurrence.

An Analysis of the Economic Burden of the Trauma Services at a Level 1 Public Sector Trauma Center in South Asia.

BACKGROUND: Incidence of road traffic injuries (RTIs) is increasing and accounting for country's 3% gross domestic product. It is crucial to perform a cost analysis of trauma systems to allocate resources judiciously. AIM AND OBJECTIVES: To study the economic burden of trauma care on the patient attending a level I trauma center including stratification of costs according to injury. MATERIALS AND METHODS: This is a prospective study, with patients of polytrauma (Injury Severity Score >16) admitted in the center. Cost analysis (cost descriptive study) was done by calculating direct costs to hospital by bottom-up microcosting considering fixed and recurrent costs including reference unit prices (RUPs). According to the anatomical site of injuries, major injury groups (MIGs) costs were also analyzed. RESULTS: The demographics including mode of injury were similar to other studies. The RUP's and MIG's were defined which represented majority of the sample size. Due to highly subsidized nature of services in this Government institute, the cost to patient is less compared to other countries. Still, the total expenditure incurred by the low-income group was higher than the minimum wages at that time. The creation of plausible RUP's and the grouping of MIG's can help in reducing the costs by targeting and implementing strategic cost reduction measures. CONCLUSION: The study has shown that microcosting is feasible. Considering the low-income population demanding trauma services, further efforts are required to reduce costs substantially.

Tumor-targeted silencing of the peptide transporter TAP induces potent antitumor immunity.

Neoantigen burden is a major determinant of tumor immunogenicity, underscored by recent clinical experience with checkpoint blockade therapy. Yet the majority of patients do not express, or express too few, neoantigens, and hence are less responsive to immune therapy. Here we describe an approach whereby a common set of new antigens are induced in tumor cells in situ by transient downregulation of the transporter associated with antigen processing (TAP). Administration of TAP siRNA conjugated to a broad-range tumor-targeting nucleolin aptamer inhibited tumor growth in multiple tumor models without measurable toxicity, was comparatively effective to vaccination against prototypic mutation-generated neoantigens, potentiated the antitumor effect of PD-1 antibody or Flt3 ligand, and induced the presentation of a TAP-independent peptide in human tumor cells. Treatment with the chemically-synthesized nucleolin aptamer-TAP siRNA conjugate represents a broadly-applicable approach to increase the antigenicity of tumor lesions and thereby enhance the effectiveness of immune potentiating therapies.

Downregulation of Sp1 by Minnelide leads to decrease in HSP70 and decrease in tumor burden of gastric cancer.

BACKGROUND: Gastric cancer is the third leading cause of cancer related mortality worldwide with poor survival rates. Even though a number of chemotherapeutic compounds have been used against this disease, stomach cancer has not been particularly sensitive to these drugs. In this study we have evaluated the effect of triptolide, a naturally derived diterpene triepoxide and its water soluble pro-drug Minnelide on several gastric adenocarcinoma cell lines both as monotherapy and in combination with CPT-11. METHODS: Gastric cancer cell lines MKN28 and MKN45 were treated with varying doses of triptolide in vitro. Cell viability was measured using MTT based assay kit. Apoptotic cell death was assayed by measuring caspase activity. Effect of the triptolide pro-drug, Minnelide, was evaluated by implanting the gastric cancer cells subcutaneously in athymic nude mice. RESULTS: Gastric cancer cell lines MKN28 and MKN45 cells exhibited decreased cell viability and increased apoptosis when treated with varying doses of triptolide in vitro. When implanted in athymic nude mice, treatment with Minnelide reduced tumor burden in both MKN28 derived tumors as well as MKN45 derived tumors. Additionally, we also evaluated Minnelide as a single agent and in combination with CPT-11 in the NCI-N87 human gastric tumor xenograft model. CONCLUSION: Our results indicated that the combination of Minnelide with CPT-11 resulted in significantly smaller tumors compared to control. These studies are extremely encouraging as Minnelide is currently undergoing phase 1 clinical trials for gastrointestinal cancers.

Wells criteria for DVT is a reliable clinical tool to assess the risk of deep venous thrombosis in trauma patients.

BACKGROUND: Deep Vein Thrombosis (DVT) is a common complication in trauma patients. Venous duplex surveillance is used widely for the diagnosis of DVT, however, there is controversy concerning its appropriate use. The Wells criterion is a clinically validated scoring system in an outpatient setting, but its use in trauma patients has not been studied. This study evaluated the application of the Wells scoring system in trauma population. METHODS: Wells scores were calculated retrospectively for all patients who were admitted to the trauma service and underwent Venous Duplex Scanning (VDS) at the author's institution between 2012 and 2013. Correlation of Wells score with DVT and its efficacy in risk stratifying the patients after trauma was analyzed using linear correlation and receiver operating characteristic (ROC) curve. Sensitivity and specificity of Wells score in ruling out or ruling in DVT were calculated in various risk groups. RESULTS: Of 298 patients evaluated, 18 (6 %) patients were positive for DVT. A linear correlation was present between Wells score and DVT with R (2) = 0.88 (p = 0.0016). Median Wells score of patients without DVT was 1 (1-3) compared to a median score of 2 (1-5) in those with DVT (p < 0.0001). In low risk patients (scores <1), Wells scoring was able to rule out the possibility of DVT with a sensitivity of 100 % and NPV of 100 %, while in moderate-high risk patients (scores ≥2), it was able to predict DVT with a specificity of 90 %. Area under ROC curve was 0.859 (p < 0.0001) demonstrating the accuracy of Wells scoring system for DVT risk stratification in post trauma patients. CONCLUSIONS: A Wells score of <1 can reliably rule out the possibility of DVT in the trauma patients. Risk of developing DVT correlates linearly with Wells score, establishing it as a valid pretest tool for risk stratification.

Impaired Synthesis of Stromal Components in Response to Minnelide Improves Vascular Function, Drug Delivery, and Survival in Pancreatic Cancer.

PURPOSE: Pancreatic cancer stromal microenvironment is considered to be the major reason for failure of conventional and targeted therapy for this disease. The desmoplastic stroma, comprising mainly collagen and glycosaminoglycans like hyaluronan (HA), is responsible for compression of vasculature in the tumor resulting in impaired drug delivery and poor prognosis. Minnelide, a water-soluble prodrug of triptolide currently in phase I clinical trial, has been very effective in multiple animal models of pancreatic cancer. However, whether Minnelide will have efficacious delivery into the tumor despite the desmoplastic stroma has not been evaluated before. EXPERIMENT DESIGN: Patient tumor-derived xenografts (PDX) and spontaneous pancreatic cancer mice were treated with 0.42 and 0.21 mg/kg body weight for 30 days. Stromal components were determined by IHC and ELISA-based assays. Vascular functionality and drug delivery to the tumor were assessed following treatment with Minnelide. RESULT: Our current study shows that treatment with Minnelide resulted in reduction of ECM components like HA and collagen in the pancreatic cancer stroma of both the spontaneous KPC mice as well as in patient tumor xenografts. Furthermore, treatment with Minnelide improved functional vasculature in the tumors resulting in four times more functional vessels in the treated animals compared with untreated animals. Consistent with this observation, Minnelide also resulted in increased drug delivery into the tumor compared with untreated animals. Along with this, Minnelide also decreased viability of the stromal cells along with the tumor cells in pancreatic adenocarcinoma. CONCLUSIONS: In conclusion, these results are extremely promising as they indicate that Minnelide, along with having anticancer effects is also able to deplete stroma in pancreatic tumors, which makes it an effective therapy for pancreatic cancer.

Minnelide Overcomes Oxaliplatin Resistance by Downregulating the DNA Repair Pathway in Pancreatic Cancer.

INTRODUCTION: Oxaliplatin is part of pancreatic cancer therapy in the FOLFIRINOX or GEMOX/XELOX regimen. DNA damage repair is one of the factors responsible for oxaliplatin resistance that eventually develops in this cancer. Triptolide/Minnelide has been shown to be effective against pancreatic cancer in preclinical trials. In this study, we evaluated the efficacy of combination of triptolide and oxaliplatin against pancreatic cancer. METHODS: Highly aggressive pancreatic cancer cells (MIA PaCa-2 and PANC-1) were treated with oxaliplatin (0-10 µM), low-dose triptolide (50 nM), or a combination of both for 24-48 h. Cell viability, apoptosis, and DNA damage were evaluated by appropriate methods. Nucleotide excision repair pathway components were quantitated using qPCR and Western blot. Combination of low doses of Minnelide and oxaliplatin was tested in an orthotopic murine model of pancreatic cancer. RESULTS: Proliferation of pancreatic cancer cells was markedly inhibited by combination treatment. Triptolide potentiated apoptotic cell death induced by oxaliplatin and sensitized cancer cells towards oxaliplatin-induced DNA damage by suppressing the oxaliplatin-induced DNA damage repair pathway. Combination of low doses of Minnelide and oxaliplatin inhibited tumor progression by inducing significant apoptotic cell death in these tumors. CONCLUSIONS: Combination of low doses of Minnelide and oxaliplatin has immense potential to emerge as a novel therapeutic strategy against pancreatic cancer.

Cell-permeable iron inhibits vascular endothelial growth factor receptor-2 signaling and tumor angiogenesis.

Angiogenesis is important for tumor growth and metastasis. Hypoxia in tumors drives this angiogenic response by stabilizing Hypoxia Inducible Factors (HIF) and target genes like Vascular Endothelial Growth Factor (VEGF). HIF stability is regulated by Prolylhydroxylases (PHD)-mediated modification. Iron is an important cofactor in regulating the enzymatic activity of PHDs. Reducing intracellular iron, for instance, mimics hypoxia and induces a pro-angiogenic response. It is hypothesized that increasing the intracellular iron levels will have an opposite, anti-angiogenic effect. We tested this hypothesis by perturbing iron homeostasis in endothelial cells using a unique form of iron, Ferric Ammonium Citrate (FAC). FAC is a cell-permeable form of iron, which can passively enter into cells bypassing the transferrin receptor mediated uptake of transferrin-bound iron. Our studies show that FAC does not decrease the levels of HIF-1α and HIF-2α in endothelial cells but inhibits the autocrine stimulation of VEGF-Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) system by blocking receptor tyrosine kinase phosphorylation. FAC inhibits VEGF-induced endothelial cell proliferation, migration, tube formation and sprouting. Finally, systemic administration of FAC inhibits VEGF and tumor cell-induced angiogenesis in vivo. In conclusion, our studies show that cell-permeable iron attenuates VEGFR-2 mediated signaling and inhibits tumor angiogenesis.