IRAK4 degrader in hidradenitis suppurativa and atopic dermatitis: a phase 1 trial

Toll-like receptor-driven and interleukin-1 (IL-1) receptor-driven inflammation mediated by IL-1 receptor-associated kinase 4 (IRAK4) is involved in the pathophysiology of hidradenitis suppurativa (HS) and atopic dermatitis (AD). KT-474 (SAR444656), an IRAK4 degrader, was studied in a randomized, double-blind, placebo-controlled phase 1 trial where the primary objective was safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics and clinical activity in patients with moderate to severe HS and in patients with moderate to severe AD. KT-474 was administered as a single dose and then daily for 14 d in 105 healthy volunteers (HVs), followed by dosing for 28 d in an open-label cohort of 21 patients. Degradation of IRAK4 was observed in HV blood, with mean reductions after a single dose of ≥93% at 600-1,600 mg and after 14 daily doses of ≥95% at 50-200 mg. In patients, similar IRAK4 degradation was achieved in blood, and IRAK4 was normalized in skin lesions where it was overexpressed relative to HVs. Reduction of disease-relevant inflammatory biomarkers was demonstrated in the blood and skin of patients with HS and patients with AD and was associated with improvement in skin lesions and symptoms. There were no drug-related infections. These results, from what, to our knowledge, is the first published clinical trial using a heterobifunctional degrader, provide initial proof of concept for KT-474 in HS and AD to be further confirmed in larger trials. ClinicalTrials.gov identifier: NCT04772885 .

Targeted degradation of MERTK and other TAM receptor paralogs by heterobifunctional targeted protein degraders

TAM receptors (TYRO3, AXL, and MERTK) comprise a family of homologous receptor tyrosine kinases (RTK) that are expressed across a range of liquid and solid tumors where they contribute to both oncogenic signaling to promote tumor proliferation and survival, as well as expressed on myeloid and immune cells where they function to suppress host anti-tumor immunity. In recent years, several strategies have been employed to inhibit TAM kinases, most notably small molecule tyrosine kinase inhibitors and inhibitory neutralizing monoclonal antibodies (mAbs) that block receptor dimerization. Targeted protein degraders (TPD) use the ubiquitin proteasome pathway to redirect E3 ubiquitin ligase activity and target specific proteins for degradation. Here we employ first-in-class TPDs specific for MERTK/TAMs that consist of a cereblon E3 ligase binder linked to a tyrosine kinase inhibitor targeting MERTK and/or AXL and TYRO3. A series of MERTK TPDs were designed and investigated for their capacity to selectively degrade MERTK chimeric receptors, reduce surface expression on primary efferocytic bone marrow-derived macrophages, and impact on functional reduction in efferocytosis (clearance of apoptotic cells). We demonstrate proof-of-concept and establish that TPDs can be tailored to either selectivity degrades MERTK or concurrently degrade multiple TAMs and modulate receptor expression in vitro and in vivo. This work demonstrates the utility of proteome editing, enabled by tool degraders developed here towards dissecting the therapeutically relevant pathway biology in preclinical models, and the ability for TPDs to degrade transmembrane proteins. These data also provide proof of concept that TPDs may serve as a viable therapeutic strategy for targeting MERTK and other TAMs and that this technology could be expanded to other therapeutically relevant transmembrane proteins.

Selective IRAK4 degradation, not kinase inhibition, blocks TLR-activated NF-Kb and p38 Signaling leading to broad cytokine inhibition

IL-1R/TLR activation plays a central role in the pathophysiology of multiple autoimmune and inflammatory diseases via the Myddosome that is dependent on both the kinase and scaffolding functions of Interleukin-1 receptor associated kinase 4 (IRAK4). Therefore, hetero-bifunctional molecules that selectively target IRAK4 for degradation and elimination by the ubiquitin proteasome pathway have the greatest potential to block IL-1R/TLR signaling, including NF-kb activation and cytokine production. To interrogate downstream signaling, phosphorylation events were monitored in monocytes and B cells following TLR7/8 or TLR9 activation, respectively. IRAK4 degradation, but not kinase inhibition, inhibited NF-kb p65 activation and phosphorylation of p38 pathway members by TLR agonists in both cell types. PBMCs pretreated with an IRAK4 degrader and then stimulated with the TLR7/8 agonist, R848, exhibited significantly broader inhibition of cytokines (IL-6, TNFa, IL-8 and IL-1b) compared to those pretreated with a selective IRAK4 kinase inhibitor. Compound washout experiments demonstrated a sustained effect of IRAK4 degrader on both target pharmacodynamics and cytokine inhibition that was differentiated from IRAK4 kinase inhibition. Overall, through removal of both scaffolding and kinase functions, IRAK4 degradation demonstrated greater activity compared to kinase inhibition across multiple TLR stimuli and cell types. These data highlight the potential for IRAK4 degraders to block multiple TLR signaling pathways across different immune cell types and thereby impact TLR/IL-1R-driven inflammatory and autoimmune diseases.

IRAK4 degradation abrogates cytokine release and improves disease endpoints in murine models of IL-33/36- as well as Th17-driven inflammation

Interleukin-1 receptor associated kinase 4 (IRAK4) plays a critical role in TLR and IL-1R mediated inflammation through its catalytic and scaffolding functions, making it an attractive target for the treatment of immune-inflammatory diseases. Kymera has developed oral heterobifunctional molecules that selectively target IRAK4 for degradation by the ubiquitin-proteasome pathway. These degraders have broad and potent activity in-vitro against LPS + IL-1β-induced proinflammatory cytokine and chemokine production that is superior to IRAK4 kinase inhibitors. We evaluated their efficacy in comparison to kinase inhibition in-vivo in both mechanistic, and disease models of skin and CNS inflammation. IRAK4 degraders were administered to mice in models of skin inflammation induced by either IL-33 or IL-36, as well as in an EAE model of Th17-mediated CNS inflammation. In IL-33- and IL-36-induced skin inflammation, IRAK4 degradation resulted in dose-dependent decreases in ear thickness as well as local and systemic cytokines/chemokines that was superior to kinase inhibition. In MOG-induced EAE, IRAK4 degradation was superior to kinase inhibition and significantly reduced disease scores to levels comparable to a S1P receptor agonist. These data demonstrate the broad activity of IRAK4 degradation and its superiority over kinase inhibition in alleviating inflammation induced by IL-1 family cytokines as well as antigen-dependent Th17-mediated inflammation in models relevant to human disease.

A pediatric case of SAPHO-CNO syndrome with clinical correlation between cutaneous and osteoarticular features

Synovitis acne pustulosis hyperostosis osteitis (SAPHO) and chronic nonbacterial osteomyelitis (CNO) represent overlapping osteoarticular autoinflammatory syndromes, with a minority displaying neutrophilic skin features at the time of diagnosis. The pathophysiological link and chronological timeframe between skin and osteoarticular findings remain ambiguous, which in turn can manifest in diagnostic delay. We present a rare pediatric case of SAPHO-CNO with a clear association between cutaneous and osteoarticular symptoms, treated with nonsteroidal anti-inflammatory medications, corticosteroids, and intravenous pamidronate. By raising physician awareness of these syndromes, we hope that appropriate management will be initiated in a more timely fashion avoiding unnecessary investigations and treatment.

Abstract LB-088: A STAT3 selective targeted protein degrader decreases the immunesuppressive tumor microenvironment and drives antitumor activity in preclinical models

Signal transducer and activator of transcription 3 (STAT3) has been implicated in multiple aspects of tumorigenesis. In addition to increasing cancer cell proliferation and survival, constitutively activated STAT3 is proposed to regulate cross-talk between tumor, stroma and immune cells to promote immune-evasion. STAT3 activity in tumors promotes the production of immune-suppressive factors that activate STAT3 in diverse immune-cell subsets. Mechanistically, genetic studies support a direct role of activated STAT3 in regulating myeloid cell differentiation to contribute to an immune-suppressed tumor microenvironment (TME) (Kortylewski et al.; Nat. Med. 2005 and Curr. Opin. Immunol. 2008) Therefore, STAT3 is a highly attractive target for immune-oncology. Here, we demonstrate that the degradation of STAT3 with a potent and selective STAT3 degrader reverses immune suppression in preclinical models. KYM-003 is a heterobifunctional molecule that hijacks the ubiquitin-proteasome system (UPS) for rapid STAT3 degradation. KYM-003 robustly degraded STAT3 in both human peripheral blood mononuclear cells (hPBMC)-derived monocytes and lymphocytes with DC50 < 100 nM. Degradation in hPBMCs was highly selective for STAT3 vs >10,000 other detected proteins (including all other STAT family members) as evaluated by deep tandem mass tag proteomics. IL-6 treatment of hPBMCs upregulates STAT3 phosphorylation, resulting in transcription of genes involved in myeloid cell-mediated immune suppression, such as IL-10 and CD163, a marker of M2 macrophage differentiation. Treatment of cells with KYM-003 at DC90 for 6 hours abrogated the IL-6 induced up-regulation of immune-suppressive gene signatures consistent with a role of STAT3 in mediating an immune suppressive environment by regulating macrophages and other myeloid cells. In several tumor cell lines, degradation of STAT3 by KYM-003 led to strong downregulation of PD-L1. Importantly, in the BioMap StroNSCLC (DiscoverRx), a co-culture system composed of NCI-H1299 lung cancer cells, hPBMCs and primary human fibroblasts that models immune-suppressed TME biology, KYM-003 treatment decreased angiogenic and immune-suppressive cytokines, including VEGF and IL-10, and promoted the pro-inflammatory anti-tumor cytokines IL-2, IFNg and TNFa. Lastly, administration of KYM-003 to mice bearing syngeneic tumors exhibited anti-tumor activity as monotherapy in the CT26 syngeneic model. We have shown that targeting STAT3 for degradation may have a role in restoring an immune-permissive environment in tumors by both rescuing the suppressed immunologic microenvironment and directly downregulating immune checkpoint signals in tumor cells. These data support STAT3 degraders as a promising new therapeutic modality as immune-oncology agents.Citations: Kortylewski et al (2005) Nat. Med, 11(12):1314-21. Kortylewski et al (2008) Curr. Opin. Immunol, 20(2):228-33

Citation Format: Alfredo Csibi, Bin Yang, Yogesh Chutake, Karen Yuan, Michele Mayo, Veronica Campbell, Alice McDonald, Scott Rusin, Kirti Sharma, Hari Kamadurai, Henry Li, Mike Sintchak, Sean Zhu, Sharon Townson, Anthony Slavin, Haojing Rong, Phillip Liu, Chris De Savi, Jared Gollob, Duncan Walker, Nan Ji, Nello Mainolfi. A STAT3 selective targeted protein degrader decreases the immunesuppressive tumor microenvironment and drives antitumor activity in preclinical models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-088.

Abstract 5222: Degraders targeting both IRAK4 and IMiD substrates show combinatorial effects leading to broader activity with durable and complete regressions in MYD88 mutant lymphoma xenografts in vivo

Targeted protein degraders (TPD) are heterobifunctional small molecules that employ the ubiquitin degradation system to drive the selective degradation of target proteins. In approximately one third of B-cell lymphomas, gain of function mutations in MYD88 constitutively activate the myddosome and drive proliferation and survival through NFkB and AP1 signaling. IRAK4, is a key component of the myddosome and IRAK4 TPD show potent and selective IRAK4 degradation and preferential activity in MYD88 mutated B cell lymphoma models. Notably, the activity of IRAK4 degraders is superior to kinase inhibition, supporting the essential scaffolding role of IRAK4 in Myddosome signaling. An important goal of cancer therapy is to drive to deep and durable responses in patients, and this is frequently achieved by combination therapy. It has been suggested that blocking NFkB while simultaneously inducing a Type 1 IFN response with an IMiD (e.g. Lenalidomide Yang et al. (2012) Cancer Cell 21, 6, p723) may drive additive or synergistic antitumor activity. We have developed novel degraders that utilize an IMiD as a cereblon binder. These compounds simultaneously degrade both IRAK4 and IMiD substrates, enabling a therapeutically-relevant biological combination within a single small molecule. Here we show that dual IRAK4 and IMiD based degraders have potent antiproliferative activity across MYD88 mutant, but not MYD88WT lymphoma cell lines, with increased and broader antiproliferative and apoptosis activity relative to selective IRAK4 degraders or IMiDs alone. Several lines of evidence suggest that both IRAK4 and IMiD activity contribute to the overall superior activity of the dual degraders. Proteomic analysis demonstrates degradation of both both IRAK4 and key IMiD substrates, including Ikaros and Ailolos. This activity results in an enhanced Type 1 IFN response signature compared to selective IRAK4 degraders or IMiD alone, suggesting cooperative biological activity. Degradation of both IRAK4 and IMiD substrates corelates with cell activity, consistent with a requirement for both activities to drive cell death. In xenograft models of MYD88 mutant DLBCL, daily oral dosing of lead dual - degraders demonstrates strong antitumor activity in xenograft models of MYD88 mutant lymphoma, including durable complete regressions that can be maintained for several weeks following cessation of dosing. Regressions are associated with degradation of both IRAK4 and IMiD substrates, consistent with the dual-targeting activity of these molecules. Collectively, these data support a strategy to combine IRAK4 degradation and IMiD activity in a single molecule that will have the potential benefits of enhanced therapeutic activity, increased convenience and decreased potential for drug combination challenges, such as DDI. Lead degraders based on this synergistic profile are being advanced towards IND in 2020.

Citation Format: Duncan H. Walker, Michele Mayo, Christine Klaus, Haojing Rong, Scott Rusin, Kirti Sharma, Alice McDonald, Veronica Campbell, Joseph Kelleher, Jared Gollob, Nello Mainolfi, Matt Weiss. Degraders targeting both IRAK4 and IMiD substrates show combinatorial effects leading to broader activity with durable and complete regressions in MYD88 mutant lymphoma xenografts in vivo [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5222.

Abstract LB-272: KYM-001, a first-in-class oral IRAK4 protein degrader, induces tumor regression in xenograft models of MYD88-mutant ABC DLBCL alone and in combination with BTK inhibition

Purpose: This work assessed the antitumor activity of selective small molecule IRAK4 degraders in human ABC DLBCL cell lines in vitro and in tumor xenograft models in vivo, alone and in combination with BTK inhibition.

Introduction: ABC DLBCL comprises approximately 45% of DLBCL and has a worse outcome with R-CHOP chemotherapy compared to GCB DLBCL. Activating mutations in MYD88 occur in 30-40% of ABC DLBCL; L265P, the most prevalent MYD88 mutation, causes constitutive assembly and activation of the Myddosome. IRAK4 kinase and scaffolding functions are essential for full signaling through the Myddosome to NFκB and MAPK pathways. Kymera Therapeutics is using a chemical knockdown strategy to develop heterobifunctional small molecule IRAK4 degraders, exemplified by KYM-001, for the treatment of MYD88-driven lymphomas.

Methods: IRAK4 in human PBMC, ABC DLBCL cell lines and xenografts was quantified by immunoassays or targeted MS/MS. Myddosome signaling was monitored by mRNA and phosphoprotein endpoints. Cell viability and cell cycle were monitored by flow cytometry. Tumor xenograft studies were conducted by implanting human ABC DLBCL lines into immunocompromised mouse strains and assessing tumor volume.

Key data: KYM-001 led to potent E3 ligase-dependent degradation of IRAK4. Notably, KYM-001 more effectively inhibited TLR-activated Myddosome signaling compared to IRAK4 kinase inhibitors in human PBMC. Degradation was highly selective for IRAK4 vs >10,000 other detected proteins in the MYD88 L265P mutant ABC DLBCL line OCI-LY10. IRAK4 degradation by KYM-001 resulted in cell cycle inhibition and apoptosis within 48-72 h in ABC DLBCL, with preferential activity in MYD88-mutant vs MYD88-WT cell lines. Oral dosing of KYM-001 showed dose-dependent antitumor activity in several mouse xenograft models of human MYD88-mutant ABC DLBCL at tolerated doses and schedules. In the OCI-LY10 model, tumor regression was associated with >80% degradation of IRAK4, establishing the pharmacodynamic effect required for maximal efficacy. Since alterations in BCR signaling and MYD88 frequently co-occur in B-cell malignancies, we investigated the potential for combined activity of IRAK4 degradation and BTK inhibition. In the OCI-LY10 xenograft model, which has activating mutations in both CD79B and MYD88, BTK inhibition with ibrutinib had an additive effect on KYM-001 antitumor activity.

Conclusions: KYM-001 is a first-in-class, potent, selective and orally active IRAK4 degrader that causes tumor regression in ABC-DLBCL models. Degradation of IRAK4 removes both the kinase and scaffolding functions of IRAK4, and may be superior to kinase inhibition alone. These data support IRAK4 degraders as a promising new therapeutic opportunity for MYD88-driven lymphoma, both alone and in combination with other targeted approaches such as BTK inhibition.

Citation Format: Joseph F. Kelleher, Veronica Campbell, Jesse Chen, Jared Gollob, Nan Ji, Hari Kamadurai, Christine Klaus, Henry Li, Christine Loh, Alice McDonald, Haojing Rong, Scott Rusin, Kirti Sharma, Dominico Vigil, Duncan Walker, Matt Weiss, Karen Yuan, Yi Zhang, Laurent Audoly, Nello Mainolfi. KYM-001, a first-in-class oral IRAK4 protein degrader, induces tumor regression in xenograft models of MYD88-mutant ABC DLBCL alone and in combination with BTK inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-272.

Low-dose naltrexone: a novel treatment for Hailey-Hailey disease

Hailey-Hailey disease (chronic benign familial pemphigus) is a rare inherited dermatosis typically characterized by erosions at intertriginous sites preceded by minor trauma or stress. We report a case of treatment-resistant Hailey-Hailey disease having failed topical and oral steroids, prophylactic aciclovir and doxycycline, and systemic therapies including dapsone, acitretin and ciclosporin. Low-dose naltrexone 4·5 mg once daily was commenced following an incidental benefit in this patient's similarly affected sister. The clinical and psychological response to date has been considerable.

The Effect of Rapid Response System Revision on Standard and Specific Intensive Care Unit Outcomes in a Regional Hospital

Hospital systems for the recognition (afferent limb) and management (efferent limb) of deteriorating patients, or Rapid Response Systems (RRSs), are being mandated worldwide, in spite of conflicting evidence regarding their efficacy. We have evaluated the impact of an Adult Deterioration Detection System (Q–ADDS)–based RRS specifically on illness severity at intensive care unit (ICU) admission and ICU length of stay (LOS), as well as previously studied endpoints. We undertook a retrospective, single-centre observational study comparing equivalent 18-month periods before the Q–ADDS–based RRS, and after implementation. The primary endpoints of the study were illness severity of unplanned ICU admissions from the ward, ICU length of stay, and ICU mortality. Secondary endpoints were RRS call numbers, rate of unplanned ICU admissions, and ward-based cardiorespiratory arrests. Following the introduction of the new RRS, Acute Pain and Chronic Health Evaluation (APACHE) II (17 versus 21, P <0.001), APACHE III (64 versus 68, P=0.011) and Simplified Acute Physiology Score (35 versus 38, P=0.044) scores at ICU admission from the ward were reduced. Fewer patients were in the >50% predicted mortality range of APACHE II (16% versus 32%, P <0.001), APACHE III (18% versus 28%, P=0.012) and Simplified Acute Physiology Score (14% versus 24%, P=0.006). ICU mortality was unchanged (13.7% versus 13.8%, P=0.93). ICU LOS was reduced (3 versus 4 days, P=0.02); prolonged stay (>7 days) was not significantly changed (19% versus 27%, P=0.055). Unplanned ICU admissions, cardiorespiratory arrests and hospital mortality were unchanged. The frequency of RRS activation (48 versus 11 per 1,000 admissions, P <0.001) was markedly increased. This Q–ADDS form–based RRS has resulted in lower illness severity at ICU admission from the ward, and fewer patients with scores associated with a >50% predicted mortality. Overall, ICU length of stay was reduced. These specific outcomes may reliably reflect RRS efficacy, even in smaller centres.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Involvement and targeted intervention of dysregulated Hedgehog signaling in osteosarcoma

BACKGROUND

During development, the Hedgehog pathway plays important roles regulating the proliferation and differentiation of chondrocytes, providing a template for growing bone. In this study, the authors investigated the components of dysregulated Hedgehog signaling as potential therapeutic targets for osteosarcoma.

METHODS

Small-molecule agonists and antagonists that modulate the Hedgehog pathway at different levels were used to investigate the mechanisms of dysregulation and the efficacy of Hedgehog blockade in osteosarcoma cell lines. The inhibitory effect of a small-molecule Smoothened (SMO) antagonist, IPI-926 (saridegib), also was examined in patient-derived xenograft models.

RESULTS

An inverse correlation was identified in osteosarcoma cell lines between endogenous glioma-associated oncogene 2 (GLI2) levels and Hedgehog pathway induction levels. Cells with high levels of GLI2 were sensitive to GLI inhibition, but not SMO inhibition, suggesting that GLI2 overexpression may be a mechanism of ligand-independent activation. In contrast, cells that expressed high levels of the Hedgehog ligand gene Indian hedgehog (IHH) and the target genes patched 1 (PTCH1) and GLI1 were sensitive to modulation of both SMO and GLI, suggesting ligand-dependent activation. In 2 xenograft models, active autocrine and paracrine, ligand-dependent Hedgehog signaling was identified. IPI-926 inhibited the Hedgehog signaling interactions between the tumor and the stroma and demonstrated antitumor efficacy in 1 of 2 ligand-dependent models.

CONCLUSIONS

The current results indicate that both ligand-dependent and ligand-independent Hedgehog dysregulation may be involved in osteosarcoma. It is the first report to demonstrate Hedgehog signaling crosstalk between the tumor and the stroma in osteosarcoma. The inhibitory effect of IPI-926 warrants additional research and raises the possibility of using Hedgehog pathway inhibitors as targeted therapeutics to improve treatment for osteosarcoma.

The pre-clinical absorption, distribution, metabolism and excretion properties of IPI-926, an orally bioavailable antagonist of the hedgehog signal transduction pathway

1. IPI-926 is a novel semisynthetic cyclopamine derivative that is a potent and selective Smoothened inhibitor that blocks the hedgehog signal transduction pathway. 2. The in vivo clearance of IPI-926 is low in mouse and dog and moderate in monkey. The volume of distribution is high across species. Oral bioavailability ranges from moderate in monkey to high in mouse and dog. Predicted human clearance using simple allometry is low (24 L h(-1)), predicted volume of distribution is high (469 L) and predicted half-life is long (20 h). 3. IPI-926 is highly bound to plasma proteins and has minimal interaction with human α-1-acid glycoprotein. 4. In vitro metabolic stability ranges from stable to moderately stable. Twelve oxidative metabolites were detected in mouse, rat, dog, monkey and human liver microsome incubations and none were unique to human. 5. IPI-926 is not a potent reversible inhibitor of CYP1A2, 2C8, 2C9 or 3A4 (testosterone). IPI-926 is a moderate inhibitor of CYP2C19, 2D6 and 3A4 (midazolam) with KI values of 19, 16 and 4.5 µM, respectively. IPI-926 is both a substrate and inhibitor (IC50 = 1.9 µM) of P-glycoprotein. 6. In summary, IPI-926 has desirable pre-clinical absorption, distribution, metabolism and excretion properties.

Smoking is a major risk factor for anastomotic leak in patients undergoing low anterior resection

AIM

To examine modifiable risk factors for anastomotic leak in patients undergoing low anterior resection.

METHOD

In total 233 patients undergoing low anterior resection for benign and malignant disease over a 10-year period at a single surgical unit were identified from a prospective database. The relationships between anastomotic leak and 17 variables were examined, including patient demographics, operative technique, tumour pathology, preoperative physiological function and smoking status.

RESULTS

The majority (91%) of operations were carried out for rectal cancers, and 24 procedures (10%) were performed with laparoscopic assistance. The overall anastomotic leak rate was 14% (33/233). Patients with anastomotic leak had higher 30-day mortality (6%vs 1%, P<0.05) and stayed significantly longer in hospital (median 23 vs 10 days, P<0.001). On multivariate analysis, current smokers (OR 3.68, 95% CI 1.38-9.82, P=0.009) and patients with evidence of metastatic malignant disease (OR 3.43, 95% CI 1.29-9.13, P=.013) were at increased risk of anastomotic leak.

CONCLUSION

Smoking and the presence of metastatic disease are major risk factors for the development of anastomotic leak following low anterior resection.

Abstract 979: The anti-tumor activity of the Smoothened inhibitor IPI-926 in models of residual disease is time dependent

Although response rates can be high for some solid tumors and hematologic malignancies following treatment, cure rates are low and there is a need to extend the duration of response and overall survival after remission. This relapse is attributed to the presence of residual malignant cells that remain undetected after primary treatment and in many instances the presence of these residual tumor cells eventually leads to disease recurrence and shortened survival. The role of the Hedgehog (Hh) pathway in cancer has been well established, with both ligand-independent signaling due to genetic mutations, as well as ligand-dependent signaling, in which Hh signaling occurs either directly to the tumor cells or to the tumor microenvironment being observed. Moreover, it has been shown that Hh ligand produced by tumor cells acts on stromal cells and inhibition of this interaction results in alterations to the tumor-associated stroma and significant inhibition of tumor growth. IPI-926 is a potent and selective Hh pathway antagonist that inhibits the key signaling membrane protein Smoothened (Smo). IPI-926 delays tumor regrowth post-cytoreduction with either standard of care chemotherapy or targeted therapy in pre-clinical xenograft models of small cell lung (SCLC), non-small cell lung (NSCLC) and prostate cancer. Data reported here show that the activity of IPI-926 in this post-therapy setting exhibits a strict time-dependence, or “efficacy window”. In both the Lx-22 SCLC and H1650 NSCLC models, delaying the time between cytoreductive therapy and initiation of IPI-926 treatment resulted in significant loss of anti-tumor activity. To investigate the molecular consequences underlying this loss of activity, RT-PCR analysis of tumors from different time points post therapy was performed. These results showed upregulation of human Hh ligand in the tumors in response to cytoreductive therapy with subsequent increased Hh signaling in the murine-derived stromal cells. IPI-926 abrogated this signaling. In addition, histological and immunohistochemical analysis demonstrated that IPI-926 induced significant changes in the tumor microenvironment post therapy. Taken together, these data suggest that the administration of IPI-926 post cytoreductive therapy could potentially be beneficial in the residual disease setting in multiple cancer types and warrants further investigation. Moreover, the timing of IPI-926 administration post therapy is critical for this benefit. IPI-926 is currently being evaluated in three Phase 2 clinical trials designed to explore multiple approaches to target ligand-dependent activation of the Hh pathway: 1) a randomized Phase 2 trial in combination with gemcitabine in patients with metastatic pancreatic cancer; 2) a randomized Phase 2 in patients with metastatic or locally advanced chondrosarcoma; and 3) a single-arm Phase 2 trial in patients with myelofibrosis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 979. doi:1538-7445.AM2012-979

Tissue Engineering of Cartilage; Can Cannabinoids Help?

This review discusses the role of the cannabinoid system in cartilage tissue and endeavors to establish if targeting the cannabinoid system has potential in mesenchymal stem cell based tissue-engineered cartilage repair strategies. The review discusses the potential of cannabinoids to protect against the degradation of cartilage in inflamed arthritic joints and the influence of cannabinoids on the chondrocyte precursors, mesenchymal stem cells (MSCs). We provide experimental evidence to show that activation of the cannabinoid system enhances the survival, migration and chondrogenic differentiation of MSCs, which are three major tenets behind the success of a cell-based tissue-engineered cartilage repair strategy. These findings highlight the potential for cannabinoids to provide a dual function by acting as anti-inflammatory agents as well as regulators of MSC biology in order to enhance tissue engineering strategies aimed at cartilage repair.

12-Lipoxygenase is a potential therapeutic target in non-small cell lung cancer

18129

Background: Platelet-type 12-LOX is an arachidonic acid metabolising enzyme resulting in the formation of 12(S)-HETE, which stimulates tumour cell adhesion, invasion and metastasis. We examined the expression of 12-LOX in NSCLC and its role in cell survival. Methods: A549 (adenocarcinoma), SK-MES1 (squamous cell lung carcinoma), H460 and H647 (large cell lung carcinoma) were grown in serum depleted media (0.5%) and screened for 12-LOX expression by RT-PCR and western blot analysis. Cells were treated with baicalein (10uM), a selective inhibitor of 12-LOX, or 12(S)-HETE (100ng/ml) and cell survival / proliferation determined by BrdU assay. Apoptosis was determined using the multi-parameter apoptosis kit and In-cell Analyser, and also by FACS. Gene alterations following 12-LOX inhibition in both A549 and SKMES-1 cells were assessed by quantitative PCR arrays and validated by RT-PCR. A panel of retrospective resected lung tumours were stained for 12-LOX expression by immunhistochemistry. Results: All lung cancer cells lines expressed moderate levels of platelet-type 12-LOX, which was reduced following treatment for 24h with the baicalein. Baicalein decreased lung cancer survival in all cell lines, while 12(S)-HETE increased cellular proliferation. Inhibition of 12-LOX induced apoptosis in a dose dependent manner, with decreased f-actin filaments and loss of mitochondrial mass potential. QPCR array data implicated a number of genes regulating these effects which were validated by RT-PCR, many of which control apoptosis and angiogenesis. The subset of genes downregulated included bcl-2, VEGF, integrin a2 and a4. 12-LOX expression was observed in a variety of human lung cancers with different histological subtypes. Conclusions: 12- LOX is a survival factor in NSCLC. 12-LOX inhibitors decreased NSCLC survival, inducing apoptosis through mechanisms including downregulation of the bcl family of proteins, integrin receptor and angiogenic growth factors. Expression of 12-LOX in fresh resected and retrospective tissue suggests that inhibition of this enzyme is a potential therapeutic strategy in the treatment of NSCLC.

No significant financial relationships to disclose.

Cyclin and cyclin-dependent kinase substrate requirements for preventing rereplication reveal the need for concomitant activation and inhibition

DNA replication initiation in S. cerevisiae is promoted by B-type cyclin-dependent kinase (Cdk) activity. In addition, once-per-cell-cycle replication is enforced by cyclin-Cdk-dependent phosphorylation of the prereplicative complex (pre-RC) components Mcm2-7, Cdc6, and Orc1-6. Several of these controls must be simultaneously blocked by mutation to obtain rereplication. We looked for but did not obtain strong evidence for cyclin specificity in the use of different mechanisms to control rereplication: both the S-phase cyclin Clb5 and the mitotic cyclins Clb1-4 were inferred to be capable of imposing ORC-based and MCM-based controls. We found evidence that the S-phase cyclin Clb6 could promote initiation of replication without blocking reinitiation, and this activity was highly toxic when the ability of other cyclins to block reinitiation was prevented by mutation. The failure of Clb6 to regulate reinitiation was due to rapid Clb6 proteolysis, since this toxic activity of Clb6 was lost when Clb6 was stabilized by mutation. Clb6-dependent toxicity is also relieved when early accumulation of mitotic cyclins is allowed to impose rereplication controls. Cell-cycle timing of rereplication control is crucial: sufficient rereplication block activity must be available as soon as firing begins. DNA rereplication induces DNA damage, and when rereplication controls are compromised, the DNA damage checkpoint factors Mre11 and Rad17 provide additional mechanisms that maintain viability and also prevent further rereplication, and this probably contributes to genome stability.

Influence of strong static magnetic fields on primary cortical neurons

Intense uniform magnetic fields, such as those used in magnetic resonance imaging (MRI), are thought to exert little influence at the cellular level. Here we report modifications of the signaling cascades in rat cortical neurons cultured for 1 h in magnetic fields of up to 5 Tesla. The activation of c-Jun N-terminal kinase (JNK) increases monotonically with field strength, with a maximal activation of approximately 10% at 5 T, whereas the activation of extra cellular-regulated kinase (ERK) shows a maximum at 0.75 T ( approximately 10%). Since ERK is involved in cellular differentiation, these results indicate a magnetic induction of the signaling events associated with differentiation. However, the cells respond to further increases in field strength by evoking a stress response, since JNK is a stress-activated protein kinase. Three possible mechanisms are discussed and of these, the most plausible is magnetic field induced change in the membrane rest potential, a microscale magnetohydrodynamic effect. This mechanism most likely involves the activation of voltage dependent Ca(2+) channel opening; since intracellular Ca(2+) concentration was also found to be modified by the static magnetic field.

Aβ-mediated activation of the apoptotic cascade in cultured cortical neurones: a role for cathepsin-L

Deposition of beta-amyloid protein in the brain is a neuropathological hallmark of Alzheimer's disease. An additional feature of this disease is an upregulation of the lysosomal system, however, the role of lysosomal proteins in the pathogenesis of this neurodegenerative condition is unclear. In this study, we demonstrate that Abeta increases activity of the lysosomal protease, cathepsin-L, and promotes a transient increase in cytosolic expression of cathepsin-L in cultured cortical neurones. The increase in cathepsin-L activity and concentration in the cytosol is evident 6 h following beta-amyloid treatment. The proclivity of beta-amyloid to induce apoptotic changes, such as activation of caspase-3, cleavage of the DNA repair enzyme, poly-ADP ribose polymerase, and DNA fragmentation, were prevented by the selective cathepsin-L inhibitor Z-FF-FMK. In contrast, beta-amyloid had no effect on expression levels or cellular distribution of cathepsin-D and the cathepsin-D inhibitor peptide failed to protect cortical neurones from beta-amyloid-induced apoptosis. Thus, the results from this study demonstrate that beta-amyloid impacts on cathepsin-L as an upstream event in the neurodegenerative process and this result highlights the potential role of lysosomal components in the pathogenesis of Alzheimer's disease.

Acute opioid withdrawal on accidental injection of naltrexone

We report two 16-year-old female intravenous drug users who, after making purchases from street suppliers, both presented with symptoms of acute opioid withdrawal. Urine toxicology revealed naltrexone, a long-acting opioid antagonist used in detoxification and maintenance therapy in opioid dependence. While the safety and efficacy of opiate antagonist treatment is being debated, the present case highlights the vulnerability of this young population. The recent availability of non-prescribed opiate antagonists suggests that both health professionals and young people themselves need to be aware of their effects.

A role for c-Jun N-terminal kinase 1 (JNK1), but not JNK2, in the beta-amyloid-mediated stabilization of protein p53 and induction of the apoptotic cascade in cultured cortical neurons

beta-Amyloid (A beta) peptide has been shown to induce neuronal apoptosis; however, the mechanisms underlying A beta-induced neuronal cell death remain to be fully elucidated. The stress-activated protein kinase, c-Jun N-terminal kinase (JNK), is activated in response to cellular stress and has been identified as a proximal mediator of cell death. In the present study, expression of active JNK was increased in the nucleus and cytoplasm of A beta-treated cells. Evaluation of the nature of the JNK isoforms activated by A beta revealed a transient increase in JNK1 activity that reached its peak at 1 h and a later activation (at 24 h) of JNK2. The tumour suppressor protein, p53, is a substrate for JNK and can serve as a signalling molecule in apoptosis. In cultured cortical neurons, we found that A beta increased p53 protein expression and phosphorylation of p53 at Ser(15). Thus it appears that A beta increases p53 expression via phosphorylation-mediated stabilization of the protein. Given the lack of availability of a JNK inhibitor that can distinguish between JNK1- and JNK2-mediated effects, we employed antisense technology to deplete cells of JNK1 or JNK2 selectively. Using this strategy, the respective roles of JNK1 and JNK2 on the A beta-mediated activation of the apoptotic cascade (i.e. p53 stabilization, caspase 3 activation and DNA fragmentation) were examined. The results obtained demonstrate a role for JNK1 in the A beta-induced stabilization of p53, activation of caspase 3 and DNA fragmentation. In contrast, depletion of JNK2 had no effect on the proclivity of A beta to activate capase 3 or induce DNA fragmentation. These results demonstrate a significant role for JNK1 in A beta-mediated induction of the apoptotic cascade in cultured cortical neurons.

beta-Amyloid (1-40)-induced apoptosis of cultured cortical neurones involves calpain-mediated cleavage of poly-ADP-ribose polymerase

beta-Amyloid((1-40))-induced apoptosis of cultured cortical neurones involves calpain-mediated cleavage of poly-ADP-ribose polymerase. beta-Amyloid protein is thought to contribute to the pathophysiology of Alzheimer's disease by inducing neuronal apoptosis. Our previous work has demonstrated that beta-amyloid activates voltage-dependent Ca(2+) channels in the cortex, resulting in an increase in intracellular Ca(2+) concentration. Calpain is a Ca(2+)-dependent neutral protease which becomes activated following alterations in intracellular Ca(2+) homeostasis. In this study we have demonstrated that beta-amyloid increases calpain activity in cultured cortical neurones in a time-dependent manner. Use of the cell-permeable calpain inhibitor, MDL 28170, has identified cleavage of the DNA-repair enzyme, poly-ADP-ribose polymerase, and DNA fragmentation as downstream consequences of calpain activation. Thus, we propose that the stimulatory effect of beta-amyloid on Ca(2+) influx triggers calpain-mediated DNA fragmentation in cultured cortical neurones.

Delta 9-tetrahydrocannabinol induces the apoptotic pathway in cultured cortical neurones via activation of the CB1 receptor

Delta 9-tetrahydrocannabinol, the principal psychoactive component of marijuana, exerts a variety of effects on the CNS, including impaired cognitive function and neurobehavioural deficits. The mechanisms underlying these neuronal responses to tetrahydrocannabinol are unclear but may involve alterations in neuronal viability. Tetrahydrocannabinol has been shown to influence neuronal survival but the role of the cannabinoid receptors in the regulation of neuronal viability has not been fully clarified. In this study we demonstrate that tetrahydrocannabinol promotes the release of cytochrome c, activates caspase-3, promotes cleavage of the DNA repair enzyme poly-ADP ribose polymerase and induces DNA fragmentation in cultured cortical neurones. These effects of tetrahydrocannabinol were completely abrogated by the CB(1) receptor antagonist AM-251. The findings of this study demonstrate that tetrahydrocannabinol induces apoptosis in cortical neurones in a manner involving the CB1 subtype of cannabinoid receptor.

Lipopolysaccharide inhibits long term potentiation in the rat dentate gyrus by activating caspase-1

Lipopolysaccharide, a component of the cell wall of Gram-negative bacteria, may be responsible for at least some of the pathophysiological sequelae of bacterial infections, probably by inducing an increase in interleukin-1beta (IL-1beta) concentration. We report that intraperitoneal injection of lipopolysaccharide increased hippocampal caspase-1 activity and IL-1beta concentration; these changes were associated with increased activity of the stress-activated kinase c-Jun NH(2)-terminal kinase, decreased glutamate release, and impaired long term potentiation. The degenerative changes in hippocampus and entorhinal cortical neurones were consistent with apoptosis because translocation of cytochrome c and poly(ADP-ribose) polymerase cleavage were increased. Inhibition of caspase-1 blocked these changes, suggesting that IL-1beta mediated the lipopolysaccharide-induced changes.

The role of ceramide in the modulation of intracellular Ca2+ levels by interleukin 1 beta in rat cortical synaptosomes

We recently demonstrated that the pro-inflammatory cytokine, interleukin 1beta (IL-1beta) elevates intracellular free Ca2+ levels ([Ca2+]i) in rat cortical synaptosomes in a manner involving activation of the IL-1 receptor and stimulation of p42 mitogen-activated protein (MAP) kinase. We now report that the effects of IL-1beta on [Ca2+]i are mimicked by the sphingolipid metabolite ceramide. In cortical synaptosomes ceramide elevates [Ca2+]i in a p42 MAP kinase-dependent manner, and we conclude that the effects of IL-1beta on Ca2+ homeostasis involve ceramide as an upstream component of the p42 MAP kinase pathway.

Effect of polyethylene occlusive skin wrapping on heat loss in very low birth weight infants at delivery: a randomized trial

OBJECTIVE

Significant evaporative heat loss in the very low birth weight infant can occur in the delivery room. We investigated the effect of polyethylene wrap applied immediately at birth (without drying) on rectal temperature measured at nursery admission.

STUDY DESIGN

Sixty-two consecutive infants delivered at <32 weeks' gestation were stratified by gestational age and randomly allocated to resuscitation with polyethylene wrap. All infants were resuscitated under radiant warmers. Wraps were removed on nursery admission. Rectal temperature was taken by digital electronic thermometer.

RESULTS

Fifty-nine of 62 recruited infants completed the study. Maternal temperature, delivery room temperature, transfer-incubator temperature, and time to admission were recorded. Use of occlusive wrapping resulted in a significantly higher admission rectal temperature in infants <28 weeks' gestation (difference in means = 1.9 C, P <.001). No significant difference was seen in admission rectal temperature in infants of 28 to 31 weeks' gestation (difference in means = 0.17 C, P =.47). All 5 deaths were in the nonwrap group (vs wrap, P =.04); their mean temperature was 35.1 C versus 36.5 C in survivors (P =.001).

CONCLUSIONS

Occlusive wrapping of very low birth weight infants at delivery reduces postnatal temperature fall. This may result in a decreased mortality rate.

Biphasic modulation of intracellular Ca2+ concentration by interleukin-1beta in cortical synaptosomes: involvement of a pertussis toxin-sensitive G-protein and mitogen-activated protein kinase

The modulation of intracellular Ca2+ concentration ([Ca2+]i) by the pro-inflammatory cytokine interleukin-1beta (IL-1beta) was assessed in synaptosomes loaded with the Ca2+-sensitive dye, Fura-2AM. IL-1beta was found to exert a biphasic effect on the KCl-induced rise in [Ca2+]i, extending an inhibitory effect at lower (3.5 ng/ml) concentrations, and a stimulatory effect at high (100 ng/ml) concentrations. The inhibitory action of IL-1beta on [Ca2+]i was sensitive to pertussis toxin (PTX; 2 microg/ml), indicating a role for a PTX-sensitive G-protein, but was unaffected by the p42 mitogen-activated protein kinase kinase (MAP kinase kinase) inhibitor, PD 098059 (2 microM). In contrast, the stimulatory action of higher concentrations of IL-1beta on [Ca2+]i was blocked by PD 098059 and unaffected by PTX. We conclude that the biphasic actions of IL-1beta on the KCl-induced rise in [Ca2+]i are mediated through activation of alternative second messenger pathways.

Voltage-dependent binding and calcium channel current inhibition by an anti-alpha 1D subunit antibody in rat dorsal root ganglion neurones and guinea-pig myocytes

1. The presence of calcium channel alpha 1D subunit mRNA in cultured rat dorsal root ganglion (DRG) neurones and guinea-pig cardiac myocytes was demonstrated using the reverse transcriptase-polymerase chain reaction. 2. An antipeptide antibody targeted at a region of the voltage-dependent calcium channel alpha 1D subunit C-terminal to the pore-forming SS1-SS2 loop in domain IV (amino acids 1417-1434) only bound to this exofacial epitope if the DRG neurones and cardiac myocytes were depolarized with 30 mM K+. 3. Incubation of cells under depolarizing conditions for 2-4 h with the antibody resulted in a maximal inhibition of inward current density of 49% (P < 0.005) for DRGs and 30% (P < 0.05) for cardiac myocytes when compared with controls. 4. S-(-)-Bay K 8644 (1 microM) enhanced calcium channel currents in DRGs by 75 +/- 19% (n = 5) in neurones incubated under depolarizing conditions with antibody that had been preabsorbed with its immunizing peptide (100 micrograms ml-1). This was significantly (P < 0.05) larger than the enhancement by S-(-)-Bay K 8644 that was seen with cells incubated under identical conditions but with antibody alone, which was 15 +/- 4% (n = 5). 5. These results demonstrate the presence of calcium channel alpha 1D subunits in rat DRG neurones and guinea-pig cardiac myocytes. They also show that amino acids 1417-1434 of the alpha 1D subunit are only exposed to the extracellular face of the membrane following depolarization and that the binding of an antibody to these amino acids attenuates calcium channel current and reduces the ability of S-(-)-Bay K 8644 to enhance this current, indicating that it is an L-type current that is attenuated.

Importance of the different beta subunits in the membrane expression of the alpha1A and alpha2 calcium channel subunits: studies using a depolarization-sensitive alpha1A antibody

The plasma membrane expression of the rat brain calcium channel subunits alpha1A, alpha2-delta and the beta subunits beta1b, beta2a, beta3b and beta4 was examined by transient expression in COS-7 cells. Neither alpha1A nor alpha2-delta localized to the plasma membrane, either alone or when coexpressed. However, coexpression of alpha1A or alpha2-delta/alpha1A with any of the beta subunits caused alpha1A and alpha2 to be targetted to the plasma membrane. The alpha1A antibody is directed against an exofacial epitope at the mouth of the pore, which is not exposed unless cells are depolarized, both for native alpha1A channels in dorsal root ganglion neurons and for alpha1A expressed with a beta subunit. This subsidiary result provides evidence that either channel opening or inactivation causes a conformational change at the mouth of the pore of alpha1A. Immunostaining for alpha1A was obtained in depolarized non-permeabilized cells, indicating correct orientation in the membrane only when it was coexpressed with a beta subunit. In contrast, beta1b and beta2a were associated with the plasma membrane when expressed alone. However, this is not a prerequisite to target alpha1A to the membrane since beta3 and beta4 alone showed no differential localization, but did direct the translocation of alpha1A to the plasma membrane, suggesting a chaperone role for the beta subunits.