Development and Characterization of Selective FAK Inhibitors and PROTACs with In Vivo Activity

Focal adhesion kinase (FAK) is an attractive drug target due to its overexpression in cancer. FAK functions as a non-receptor tyrosine kinase and scaffolding protein, coordinating several downstream signaling effectors and cellular processes. While drug discovery efforts have largely focused on targeting FAK kinase activity, FAK inhibitors have failed to show efficacy as single agents in clinical trials. Here, using structure-guided design, we report the development of a selective FAK inhibitor (BSJ-04-175) and degrader (BSJ-04-146) to evaluate the consequences and advantages of abolishing all FAK activity in cancer models. BSJ-04-146 achieves rapid and potent FAK degradation with high proteome-wide specificity in cancer cells and induces durable degradation in mice. Compared to kinase inhibition, targeted degradation of FAK exhibits pronounced improved activity on downstream signaling and cancer cell viability and migration. Together, BSJ-04-175 and BSJ-04-146 are valuable chemical tools to dissect the specific consequences of targeting FAK through small-molecule inhibition or degradation.

Transforming Growth Factor-β Blockade in Pancreatic Cancer Enhances Sensitivity to Combination Chemotherapy

BACKGROUND & AIMS

Transforming growth factor-b (TGFb) plays pleiotropic roles in pancreatic cancer, including promoting metastasis, attenuating CD8 T-cell activation, and enhancing myofibroblast differentiation and deposition of extracellular matrix. However, single-agent TGFb inhibition has shown limited efficacy against pancreatic cancer in mice or humans.

METHODS

We evaluated the TGFβ-blocking antibody NIS793 in combination with gemcitabine/nanoparticle (albumin-bound)-paclitaxel or FOLFIRINOX (folinic acid [FOL], 5-fluorouracil [F], irinotecan [IRI] and oxaliplatin [OX]) in orthotopic pancreatic cancer models. Single-cell RNA sequencing and immunofluorescence were used to evaluate changes in tumor cell state and the tumor microenvironment.

RESULTS

Blockade of TGFβ with chemotherapy reduced tumor burden in poorly immunogenic pancreatic cancer, without affecting the metastatic rate of cancer cells. Efficacy of combination therapy was not dependent on CD8 T cells, because response to TGFβ blockade was preserved in CD8-depleted or recombination activating gene 2 (RAG2-/-) mice. TGFβ blockade decreased total α-smooth muscle actin-positive fibroblasts but had minimal effect on fibroblast heterogeneity. Bulk RNA sequencing on tumor cells sorted ex vivo revealed that tumor cells treated with TGFβ blockade adopted a classical lineage consistent with enhanced chemosensitivity, and immunofluorescence for cleaved caspase 3 confirmed that TGFβ blockade increased chemotherapy-induced cell death in vivo.

CONCLUSIONS

TGFβ regulates pancreatic cancer cell plasticity between classical and basal cell states. TGFβ blockade in orthotropic models of pancreatic cancer enhances sensitivity to chemotherapy by promoting a classical malignant cell state. This study provides scientific rationale for evaluation of NIS793 with FOLFIRINOX or gemcitabine/nanoparticle (albumin-bound) paclitaxel chemotherapy backbone in the clinical setting and supports the concept of manipulating cancer cell plasticity to increase the efficacy of combination therapy regimens.

Spatially Resolved Single-Cell Assessment of Pancreatic Cancer Expression Subtypes Reveals Co-expressor Phenotypes and Extensive Intratumoral Heterogeneity

Pancreatic ductal adenocarcinoma (PDAC) has been classified into classical and basal-like transcriptional subtypes by bulk RNA measurements. However, recent work has uncovered greater complexity to transcriptional subtypes than was initially appreciated using bulk RNA expression profiling. To provide a deeper understanding of PDAC subtypes, we developed a multiplex immunofluorescence (mIF) pipeline that quantifies protein expression of six PDAC subtype markers (CLDN18.2, TFF1, GATA6, KRT17, KRT5, and S100A2) and permits spatially resolved, single-cell interrogation of pancreatic tumors from resection specimens and core needle biopsies. Both primary and metastatic tumors displayed striking intratumoral subtype heterogeneity that was associated with patient outcomes, existed at the scale of individual glands, and was significantly reduced in patient-derived organoid cultures. Tumor cells co-expressing classical and basal markers were present in > 90% of tumors, existed on a basal-classical polarization continuum, and were enriched in tumors containing a greater admixture of basal and classical cell populations. Cell-cell neighbor analyses within tumor glands further suggested that co-expressor cells may represent an intermediate state between expression subtype poles. The extensive intratumoral heterogeneity identified through this clinically applicable mIF pipeline may inform prognosis and treatment selection for patients with PDAC.

SIGNIFICANCE

A high-throughput pipeline using multiplex immunofluorescence in pancreatic cancer reveals striking expression subtype intratumoral heterogeneity with implications for therapy selection and identifies co-expressor cells that may serve as intermediates during subtype switching.

Abstract A075: NCOA4-mediated ferritinophagy is a pancreatic cancer dependency via maintenance of iron bioavailability for iron-sulfur cluster proteins

Pancreatic ductal adenocarcinomas (PDAC) depend on autophagy for survival; however, the metabolic substrates that autophagy provides to drive PDAC progression are unclear. Ferritin, the cellular iron storage complex, is targeted for lysosomal degradation (ferritinophagy) by the selective autophagy adaptor Nuclear receptor coactivator 4 (NCOA4), resulting in release of iron for cellular utilization. Using patient-derived and genetically engineered murine models of PDAC we now demonstrate that ferritinophagy is upregulated in PDAC to sustain iron availability thereby promoting tumor progression. Mass spectrometry-based quantitative proteomics reveals that ferritinophagy fuels iron-sulfur cluster protein synthesis to support mitochondrial homeostasis. Targeting NCOA4 leads to tumor growth delay and prolonged survival but with development of compensatory iron acquisition pathways. Finally, enhanced ferritinophagy accelerates PDAC tumorigenesis, and an elevated ferritinophagy expression signature predicts for poor prognosis in PDAC patients. Together, our data reveal that maintenance of iron homeostasis is a critical function of PDAC autophagy, and we define NCOA4-mediated ferritinophagy as a therapeutic target in PDAC.

Citation Format: Naiara Santana-Codina, Huan Zhang, Maria Quiles del Rey, Kevin S. Kapner, Ajami Gikandi, Callum Malcolm, Clara Poupault, Miljan Kuljanin, Kristen John, Douglas E. Biancur, Brandon Chen, Nupur Das, Kristen Lowder, Connor J. Hennessey, Wesley Huang, Annan Yang, Yatrik M. Shah, Jonathan A. Nowak, Andrew J. Aguirre, Joseph D. Mancias. NCOA4-mediated ferritinophagy is a pancreatic cancer dependency via maintenance of iron bioavailability for iron-sulfur cluster proteins [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A075.

Abstract A057: Therapeutic efficacy of selective CDK7 inhibition in pancreatic cancer mediated by induction of R-loop formation, DNA replication stress and genomic instability

Pancreatic ductal adenocarcinoma (PDAC) is a devastating cancer with 5-year overall survival of less than 10% and few effective therapies. Here, we demonstrate that cyclin dependent kinase 7 (CDK7) is essential for the proliferation and viability of PDAC cells by showing potent anti-tumor efficacy for the CDK7-specific inhibitor YKL-5-124 in preclinical PDAC models. Selective CDK7 inhibition leads to G2/M cell cycle arrest and apoptosis in PDAC, while mediating a more modest transcriptional response compared with multi-targeted CDK7 inhibitors. YKL-5-124 treatment impairs DNA damage repair pathways in PDAC cells and evokes genomic instability by inducing R-loop formation and DNA replication stress in telomeric regions leading to chromosomal bridging and micronuclei formation. Furthermore, we demonstrate that selective CDK7 inhibition has in vitro and in vivo combinatorial efficacy with gemcitabine chemotherapy through pronounced induction of replication stress and apoptosis. Collectively, these findings support selective CDK7 inhibition as a promising therapeutic strategy for PDAC.

Citation Format: Annan Yang, Jie Jiang, Ziyue Li, Kevin S. Kapner, Hanrong Feng, Kristen E. Lowder, Miljan Kuljanin, Whiteny Johnson, Giselle Uribe, Jasper E. Neggers, Shengwu Liu, Tinghu Zhang, James Decaprio, Ewa Sicinska, Brian M. Wolpin, Nicholas P. Kwiatkowski, Stephanie K. Dougan, Joseph D. Mancias, Nathanael S. Gray, Andrew J. Aguirre. Therapeutic efficacy of selective CDK7 inhibition in pancreatic cancer mediated by induction of R-loop formation, DNA replication stress and genomic instability [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A057.

Abstract A052: Systematic dissection of transcriptional states in pancreatic cancer

Transcriptional states in pancreatic cancer can stratify patients by response to chemotherapy and clinical outcomes. These include the classical and basal-like states as well as a newly identified neural-like progenitor (NRP) state, which we have previously found to be enriched in primary patient tumors treated with neoadjuvant chemotherapy and radiotherapy. While several transcription factor drivers of classical and basal-like identity have been described, key regulators of the NRP state are unknown. Through in silico approaches, we identified candidate transcription factors of the NRP state, including GLIS3, a Krüppel-like zinc finger protein that mediates neuroendocrine fate during pancreatic development and differentiation of human embryonic stem cells into posterior neural progenitor cells. Our understanding of biologic and clinically-relevant attributes of transcriptional cell states remains limited by state-specific biases in various preclinical models. Existing human cell lines maintained as two-dimensional cultures tend to preferentially represent the basal-like state, whereas human three-dimensional organoid models grown in standard culture conditions best reflect the classical state. These phenotypes are therefore impacted by culture conditions as well as underlying genetic features. Furthermore, most murine pancreatic cancer models do not fully reflect the classical vs. basal-like state heterogeneity observed in humans. To enable systematic study of the classical, basal-like and NRP phenotypes, we developed isogenic KP (KrasG12D/+;Trp53FL/FL) murine organoids with a germline dCas9-VPR system to enable facile overexpression of state-specific transcription factors through CRISPR activation approaches. Quantitative PCR, RNA-sequencing, and proteomics confirmed Gata6, deltaN Trp63, and Glis3 as drivers of classical, basal-like, and NRP identity, respectively. DeltaN Trp63 organoids were further differentiated by loss of luminal morphology. Pairwise comparisons of global transcriptional alterations suggest the greatest similarities between the Gata6- and Glis3-overexpressed models, which is consistent with enhanced associations between classical and NRP states in patient tumors. Finally, although basal-like and NRP states are associated with poorer response to multi-agent chemotherapy, state-specific therapeutic sensitivities to other treatments remain incompletely defined. We therefore performed drug sensitivity assays with a panel of targeted therapies and unveiled state-specific sensitivities. These data were corroborated by drug sensitivity profiling of human patient-derived organoids and cell lines. Taken together, these results suggest a framework for defining cell state-specific vulnerabilities that may aid in stratifying and treating pancreatic cancer patients with new therapies.

Citation Format: Jimmy A. Guo, Jennifer Su, Ananya Jambhale, Julien Dilly, Connor J. Hennessey, Carina Shiau, Patrick Yu, Steven Wang, Junning Wang, Laleh Abbassi, James Neiswender, Tate Bertea, Annan Yang, Qijia Yu, Peter Westcott, Jason Schenkel, Daniel Y. Kim, Hannah I. Hoffman, Grissel Cervantes Jaramillo, Giselle A. Uribe, Westley W. Wu, Arnav Mehta, David Ting, Julian A. Pacheco, Amy Deik, Clary Clish, Francisca Vazquez, Brian Wolpin, Aviv Regev, William A. Freed-Pastor, Joseph D. Mancias, Tyler Jacks, William L. Hwang, Andrew J. Aguirre. Systematic dissection of transcriptional states in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A052.

Patients not taking a previously prescribed bone active medication now prescribed medication through Ontario FLS

In an Ontario fracture liaison service (FLS), we compared medication prescription rates among patients not taking a previously prescribed bone active medication to those with no previous prescription. Prescription rates were similar between these two groups of patients. The FLS provided a secondary opportunity for patients to initiate bone active medication.

PURPOSE

We compared bone active medication prescription rates among patients presenting to an Ontario fracture liaison service (FLS) who reported not taking a previously prescribed bone active medication to those with no history of prescription.

METHODS

Eligible patients were those screened in 39 fracture clinics between July 1, 2017, and September 15, 2019, who were not taking bone active medication at the time of screening and classified as high risk for future fracture based on CAROC or FRAX. Sociodemographic and clinical risk factor variables were assessed at screening. Bone active medication prescription rate was assessed within 6 months of screening and defined as having received a prescription for the medication from either a specialist or primary care provider. In cases where a specialist report was not available, patient self-reported data were collected. The chi-square test of independence was used to assess differences in prescription rates.

RESULTS

Of 17,575 patients screened, eligible patients were 350 with a previous prescription and 2644 without a previous prescription. Compared with patients who reported no previous prescription, those who had a previous prescription were older, more likely to be female and to report a previous fracture, and less likely to smoke. There was no statistically significant difference between the medication prescription rate of patients with a previous prescription (73.7%) compared to patients with no previous prescription (70.7%) (p = 0.157).

CONCLUSION

A large jurisdiction-wide FLS approach provided a secondary opportunity to patients who were not taking a previously prescribed bone active medication to initiate that medication.

Coordinated Transcriptional and Catabolic Programs Support Iron-Dependent Adaptation to RAS-MAPK Pathway Inhibition in Pancreatic Cancer

The mechanisms underlying metabolic adaptation of pancreatic ductal adenocarcinoma (PDA) cells to pharmacologic inhibition of RAS-MAPK signaling are largely unknown. Using transcriptome and chromatin immunoprecipitation profiling of PDA cells treated with the MEK inhibitor (MEKi) trametinib, we identify transcriptional antagonism between c-MYC and the master transcription factors for lysosome gene expression, the MiT/TFE proteins. Under baseline conditions, c-MYC and MiT/TFE factors compete for binding to lysosome gene promoters to fine-tune gene expression. Treatment of PDA cells or patient organoids with MEKi leads to c-MYC downregulation and increased MiT/TFE-dependent lysosome biogenesis. Quantitative proteomics of immunopurified lysosomes uncovered reliance on ferritinophagy, the selective degradation of the iron storage complex ferritin, in MEKi-treated cells. Ferritinophagy promotes mitochondrial iron-sulfur cluster protein synthesis and enhanced mitochondrial respiration. Accordingly, suppressing iron utilization sensitizes PDA cells to MEKi, highlighting a critical and targetable reliance on lysosome-dependent iron supply during adaptation to KRAS-MAPK inhibition.

SIGNIFICANCE

Reduced c-MYC levels following MAPK pathway suppression facilitate the upregulation of autophagy and lysosome biogenesis. Increased autophagy-lysosome activity is required for increased ferritinophagy-mediated iron supply, which supports mitochondrial respiration under therapy stress. Disruption of ferritinophagy synergizes with KRAS-MAPK inhibition and blocks PDA growth, thus highlighting a key targetable metabolic dependency. See related commentary by Jain and Amaravadi, p. 2023. See related article by Santana-Codina et al., p. 2180. This article is highlighted in the In This Issue feature, p. 2007.

NCOA4-Mediated Ferritinophagy Is a Pancreatic Cancer Dependency via Maintenance of Iron Bioavailability for Iron-Sulfur Cluster Proteins

Pancreatic ductal adenocarcinomas (PDAC) depend on autophagy for survival; however, the metabolic substrates that autophagy provides to drive PDAC progression are unclear. Ferritin, the cellular iron storage complex, is targeted for lysosomal degradation (ferritinophagy) by the selective autophagy adaptor NCOA4, resulting in release of iron for cellular utilization. Using patient-derived and murine models of PDAC, we demonstrate that ferritinophagy is upregulated in PDAC to sustain iron availability, thereby promoting tumor progression. Quantitative proteomics reveals that ferritinophagy fuels iron-sulfur cluster protein synthesis to support mitochondrial homeostasis. Targeting NCOA4 leads to tumor growth delay and prolonged survival but with the development of compensatory iron acquisition pathways. Finally, enhanced ferritinophagy accelerates PDAC tumorigenesis, and an elevated ferritinophagy expression signature predicts for poor prognosis in patients with PDAC. Together, our data reveal that the maintenance of iron homeostasis is a critical function of PDAC autophagy, and we define NCOA4-mediated ferritinophagy as a therapeutic target in PDAC.

SIGNIFICANCE

Autophagy and iron metabolism are metabolic dependencies in PDAC. However, targeted therapies for these pathways are lacking. We identify NCOA4-mediated selective autophagy of ferritin ("ferritinophagy") as upregulated in PDAC. Ferritinophagy supports PDAC iron metabolism and thereby tumor progression and represents a new therapeutic target in PDAC. See related commentary by Jain and Amaravadi, p. 2023. See related article by Ravichandran et al., p. 2198. This article is highlighted in the In This Issue feature, p. 2007.

Fragility fracture patients with a history of prior fractures more likely to present with multiple risk factors: findings from a province-wide fracture liaison service

We examined the demographic characteristics and risk factors of FLS fragility fracture patients who had sustained prior fragility fracture(s) and found that this is an important high-risk subgroup that warrants further attention within FLS priority pathways in order to disrupt their fragility fracture cycle.

PURPOSE

Our primary objective was to examine whether fragility fracture patients presenting to a provincial fracture liaison service (FLS) having a history of prior fractures, versus those without, differ in demographic characteristics and risk factors for future fracture. A secondary objective was to understand if those who report two or more prior fractures differ from those reporting one prior fracture.

METHODS

This cohort study included fragility fracture patients aged 50 + enrolled in the Ontario FLS between July 2017 and September 2019. Patients with versus those without prior fractures were compared on age, sex, index fracture site, biological parents' history of hip fracture, current fracture due to a fall, history of feeling unsteady when walking, history of falls in the past year, smoking, oral steroid use, and comorbid chronic conditions. Pearson's chi-square, Fischer's exact, and analysis of variance tests were used to assess differences.

RESULTS

Among 14,454 patients, 16.8% (n = 2428) reported a history of one or more prior fractures after the age of 40. They were significantly more likely to be older, female, with a higher number of comorbidities, with greater incidence of falls, and feel unsteady when walking. Compared to those with one prior fracture, patients with greater than one prior fracture were more likely to report falls in the past year and feel unsteady when walking.

CONCLUSION

Findings suggest that FLS fragility fracture patients who had sustained prior fragility fracture are an important high-risk subgroup that warrants further attention within FLS priority pathways in order to disrupt their fragility fracture cycle.

Sulfopin is a covalent inhibitor of Pin1 that blocks Myc-driven tumors in vivo

The peptidyl-prolyl isomerase, Pin1, is exploited in cancer to activate oncogenes and inactivate tumor suppressors. However, despite considerable efforts, Pin1 has remained an elusive drug target. Here, we screened an electrophilic fragment library to identify covalent inhibitors targeting Pin1's active site Cys113, leading to the development of Sulfopin, a nanomolar Pin1 inhibitor. Sulfopin is highly selective, as validated by two independent chemoproteomics methods, achieves potent cellular and in vivo target engagement and phenocopies Pin1 genetic knockout. Pin1 inhibition had only a modest effect on cancer cell line viability. Nevertheless, Sulfopin induced downregulation of c-Myc target genes, reduced tumor progression and conferred survival benefit in murine and zebrafish models of MYCN-driven neuroblastoma, and in a murine model of pancreatic cancer. Our results demonstrate that Sulfopin is a chemical probe suitable for assessment of Pin1-dependent pharmacology in cells and in vivo, and that Pin1 warrants further investigation as a potential cancer drug target.

Molecular basis for substrate recruitment to the PRMT5 methylosome

PRMT5 is an essential arginine methyltransferase and a therapeutic target in MTAP-null cancers. PRMT5 uses adaptor proteins for substrate recruitment through a previously undefined mechanism. Here, we identify an evolutionarily conserved peptide sequence shared among the three known substrate adaptors (CLNS1A, RIOK1, and COPR5) and show that it is necessary and sufficient for interaction with PRMT5. We demonstrate that PRMT5 uses modular adaptor proteins containing a common binding motif for substrate recruitment, comparable with other enzyme classes such as kinases and E3 ligases. We structurally resolve the interface with PRMT5 and show via genetic perturbation that it is required for methylation of adaptor-recruited substrates including the spliceosome, histones, and ribosomal complexes. Furthermore, disruption of this site affects Sm spliceosome activity, leading to intron retention. Genetic disruption of the PRMT5-substrate adaptor interface impairs growth of MTAP-null tumor cells and is thus a site for development of therapeutic inhibitors of PRMT5.

SMAD4 represses FOSL1 expression and pancreatic cancer metastatic colonization

Metastasis is a complex and poorly understood process. In pancreatic cancer, loss of the transforming growth factor (TGF)-β/BMP effector SMAD4 is correlated with changes in altered histopathological transitions, metastatic disease, and poor prognosis. In this study, we use isogenic cancer cell lines to identify SMAD4 regulated genes that contribute to the development of metastatic colonization. We perform an in vivo screen identifying FOSL1 as both a SMAD4 target and sufficient to drive colonization to the lung. The targeting of these genes early in treatment may provide a therapeutic benefit.

Abstract NG01: Synthetic lethal interaction between the ESCRT paralog enzymes VPS4A and VPS4B in cancers harboring loss of chromosome 18q or 16q

Background: Discovery of new biomarker-linked cancer therapeutic targets may enable novel drug development and ultimately lead to advances in clinical care. Somatic copy number alterations (CNAs) leading to loss of tumor suppressor gene function constitute important driver events in tumorigenesis. Unfortunately, there are few existing therapeutic options to target the oncogenic processes evoked by tumor suppressor inactivation. However, developing drugs that target tractable synthetic lethal interactions with common somatic CNAs represents a promising approach to attain cancer-selective therapeutics. Synthetic lethality refers to the observation that for certain gene pairs, inactivation of either gene is tolerated but combined loss-of-function of both genes results in decreased cell viability. Synthetic lethal relationships in cancer have been defined in several different contexts, including among paralog genes for which dependency on one paralog is conferred by loss of a second functionally redundant paralog gene. Since targeting synthetic lethal relationships in cancer may yield a wide therapeutic window of efficacy between tumor and normal cells, identification of pharmacologically tractable synthetic lethal targets remains a priority for oncology drug development programs. Results and Discussion: To systematically define synthetic lethal vulnerabilities associated with genomic loss of established tumor suppressor genes, we analyzed genome-scale CRISPR-SpCas9 and RNA interference loss-of-function screening data from over 600 cancer cell lines. We identified and prioritized 193 synthetic lethal interactions with genomic loss of one or more of 51 common tumor suppressor genes. In particular, we discovered that the paralog genes encoding vacuolar protein sorting 4 homolog A and B (VPS4A and VPS4B) are selective genetic vulnerabilities for tumors harboring genomic copy loss of SMAD4 or CDH1 due to co-deletion of VPS4B or VPS4A, respectively. VPS4B is located on the long arm (q) of chromosome 18, 12.3 Mb away from SMAD4, while VPS4A is located 0.476 Mb downstream of CDH1 (encoding E-cadherin) on chromosome 16q. Thus, cancer cells with genomic loss of VPS4B selectively depend on expression of VPS4A for survival, and tumors with loss of VPS4A depend on VPS4B expression. Co-deletion of SMAD4 and VPS4B is commonly observed in approximately 33% of human cancer, with particularly high rates of loss in pancreatic cancers (68%), colorectal (71%) and renal cell carcinomas (17%) and to a lesser extent in cancers of the bile duct, lung, prostate, esophagus, uterus, cervix and ovary. Meanwhile, loss of CDH1 and VPS4A occurs frequently in cancers of the stomach, breast, skin, colon and prostate. VPS4A and B function as AAA ATPases which are critical for the regulation of endosomal sorting complex required for transport (ESCRT), a multimeric protein complex essential for inverse membrane remodeling. The ESCRT machinery is involved in a range of cellular processes, including cytokinesis, membrane repair, autophagy and endosomal processing. VPS4A/B are believed to form asymmetric hexameric complexes that are recruited to ESCRT-III filaments to drive ESCRT-mediated membrane fission and sealing. Here, we demonstrate that suppression of VPS4A in cancer cells with reduced copy number of VPS4B leads to accumulation of CHMP4B-containing ESCRT-III filaments, cytokinesis defects, nuclear membrane abnormalities and micronucleation, ultimately resulting in G2/M cell cycle arrest and apoptosis. We also observed that VPS4 suppression leads to defects in endosomal and endoplasmic reticulum structure. Furthermore, upon VPS4A suppression, we observed potent in vivo tumor regressions, which led to markedly prolonged survival in mouse xenograft models of pancreatic cancer and rhabdomyosarcoma harboring genomic loss of VPS4B. To understand regulators of VPS4A dependency, we performed a CRISPR-SpCas9 genome-scale screen in a pancreatic cancer cell line in the context of VPS4A suppression. We identified multiple genes that promote or suppress VPS4A dependency. Cancer cell sensitivity to VPS4A suppression was potently enhanced by disruption of regulators of the abscission checkpoint, including genes encoding the ULK3 kinase and the ESCRT-III proteins CHMP1A and CHMP1B. The abscission checkpoint is a genome protection mechanism that relies on Aurora B kinase (AURKB) and ESCRT-III subunits to delay abscission in response to chromosome mis-segregation to avoid DNA damage and aneuploidy. These findings suggest that inhibition of the ESCRT pathway and blockade of the abscission checkpoint could provide strategies to further enhance sensitivity of cancer cells to VPS4A suppression. Moreover, through CRISPR-SpCas9 screening and integrative transcriptomic and proteomic analysis, we also identified a strong correlation between baseline interferon response gene expression and VPS4A dependency. Indeed, when we treated VPS4B-deficient cells with interferon-β and interferon-γ to induce interferon signaling, we observed a pronounced sensitization of these cells to VPS4A depletion, thus suggesting that immune signals from the tumor microenvironment may influence VPS4 dependency. These data collectively suggest potential future therapeutic strategies for combination with VPS4A inhibition. Finally, we demonstrate through mutant rescue experiments that the ATPase domain is critical for the function of VPS4A in mediating survival of cells with partial copy loss of VPS4B. Furthermore, we provide data that elucidate the degree to which VPS4A and VPS4B cooperate and form functional complexes in human cancer cells. Although VPS4A and B demonstrate 80.5% homology, the development of small molecules that differentially target VPS4A in cells with VPS4B loss or VPS4B in cells with VPS4A loss remains a tractable possibility due to small structural differences near the ATP-binding pocket. Moreover, combined inhibition of VPS4A and VPS4B may also prove effective and clinically tolerable given a potential therapeutic window arising from gene dosage alterations and differences in total VPS4A/B levels in tumor versus normal cells.

Citation Format: Jasper E. Neggers, Brenton Paolella, Adhana Asfaw, Michael V. Rothberg, Tom A. Skipper, Radha Kalekar, Michael Burger, Neekesh Dharia, Guillaume Kugener, Jeremie Kalfon, Nancy Dumont, Yvonne Li, Liam Spurr, Annan Yang, Wenbo Wu, AndrewAdam Durbin, Brian M. Wolpin, David E. Root, Jesse Boehm, Andrew D. Cherniack, Aviad Tsherniak, Andrew L. Hong, William C. Hahn, Kimberly Stegmaier, Todd Golub, Francisca Vazquez, Andrew J. Aguirre. Synthetic lethal interaction between the ESCRT paralog enzymes VPS4A and VPS4B in cancers harboring loss of chromosome 18q or 16q [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr NG01.

Patients 80 + have similar medication initiation rates to those aged 50-79 in Ontario FLS

Among individuals presenting to an Ontario FLS, we compared bone active medication initiation rates of patients 80 years and older with those 50-79 years old. After accounting for fracture risk status, there was no statistically significant difference in medication initiation rates between the two age groups INTRODUCTION: A Fracture Liaison Service (FLS) offers post-fracture services to individuals over the age of 50 years and could potentially address age inequities in pharmacotherapy often observed for older adults. Among individuals presenting to an Ontario FLS and classified as being at high risk for future fracture, our objective was to compare bone active medication initiation rates of patients 80 years and older with those 50-79 years old.

METHODS

In 39 FLS fracture clinics across Ontario, Canada, fracture prevention coordinators identified, assessed, and facilitated the referral of eligible patients for bone densitometry, fracture risk assessment, and implementation of pharmacotherapy in patients classified as high risk for future fracture. Variables assessed at baseline included age, sex, marital status, living location, fracture location, history of previous fracture, parent's history of hip fracture, history of falls, and fracture risk status. At 6 months, bone active medication initiation was assessed in patients classified as high risk for future fracture. The Chi-square test of independence was used to compare medication initiation rates between patients 80 + and those 50-79 years old.

RESULTS

Our sample size consisted of 808 patients aged 50-79 years and 346 aged 80 + years. After accounting for fracture risk status, there was no statistically significant difference in medication initiation rates of patients 50-79 and 80 + years old (76.9% versus 73.7%, p = 0.251).

CONCLUSION

A systematic approach to identifying patients at high risk for future fracture and tailoring treatment recommendations to these patients appeared to eliminate differences in treatment initiation rates based on older age.

cIAP1/2 antagonism eliminates MHC class I-negative tumors through T cell-dependent reprogramming of mononuclear phagocytes

Loss of major histocompatibility complex (MHC) class I and interferon-γ (IFN-γ) sensing are major causes of primary and acquired resistance to checkpoint blockade immunotherapy. Thus, additional treatment options are needed for tumors that lose expression of MHC class I. The cellular inhibitor of apoptosis proteins 1 and 2 (cIAP1/2) regulate classical and alternative nuclear factor κB (NF-κB) signaling. Induction of noncanonical NF-κB signaling with cIAP1/2 antagonists mimics costimulatory signaling, augmenting antitumor immunity. We show that induction of noncanonical NF-κB signaling induces T cell-dependent immune responses, even in β2-microglobulin (β2M)-deficient tumors, demonstrating that direct CD8 T cell recognition of tumor cell-expressed MHC class I is not required. Instead, T cell-produced lymphotoxin reprograms both mouse and human macrophages to be tumoricidal. In wild-type mice, but not mice incapable of antigen-specific T cell responses, cIAP1/2 antagonism reduces tumor burden by increasing phagocytosis of live tumor cells. Efficacy is augmented by combination with CD47 blockade. Thus, activation of noncanonical NF-κB stimulates a T cell-macrophage axis that curtails growth of tumors that are resistant to checkpoint blockade because of loss of MHC class I or IFN-γ sensing. These findings provide a potential mechanism for controlling checkpoint blockade refractory tumors.

Vibrio harveyi isolated from marine aquaculture species in eastern China and virulence to the large yellow croaker (Larimichthys crocea)

AIMS

Diseases of maricultured species caused by Vibrio harveyi are increasing in China and other regions. This study examined the genetic diversity, antimicrobial susceptibility, plasmid profiles and virulence potential of the V. harveyi isolated from marine organisms farmed in two provinces in eastern China between 2014 and 2019.

METHODS AND RESULTS

A total of 54 V. harveyi were obtained from seven marine species. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting revealed substantial genetic heterogeneity among the V. harveyi isolates. There was no significant correlation between ERIC-PCR genotypes and host origins or fish farms. All the isolates were resistant to amoxicillin and ampicillin, and 79·6% to kanamycin. We found that 61·1% of the V. harveyi isolates had plasmid(s) and there were 14 different plasmid profiles. Most isolates from fish hosts (76·5%) contained plasmids; however, 75% of isolates from nonfish hosts lacked plasmids. Experimental infection results showed that isolates with plasmid(s) were more virulent to large yellow croaker than isolates lacking plasmids (P < 0·05).

CONCLUSIONS

This study confirmed that V. harveyi isolates obtained from animals farmed in the coastal region of east China were genetically diverse. Our results suggest that the virulence of various V. harveyi strains to fish is associated with the plasmids they carry.

SIGNIFICANCE AND IMPACT OF THE STUDY

More than 50% of the V. harveyi isolates carried one to 11 plasmids. The plasmid-borne traits of V. harveyi strains might be important for host adaptation and virulence, but they were not associated with susceptibility to the tested antibiotics.

A graphical method for breaking logical loops based on multi-tree structure

Logical loops or circular logics, interpreted as circular supporting relations among systems, remain a longstanding challenge in the probabilistic safety assessment (PSA). Logical loops are commonly found in complex industrial systems. Due to the existence of the logical loops, the minimal cut sets cannot be directly obtained. In order to solve this problem, the logical loops should be broken properly. This paper proposes a graphical method based on multi-tree structure. By constructing the simplified multi-tree, logical loops both in linearly and non-linearly interrelated systems are solved. To illustrate this method, examples of linearly interrelated systems and non-linearly interrelated systems are given in this paper. As a supplement, this method is applied to the well-known complex logical loops in the nuclear power plant. It shows that this method is highly intuitive and efficient by means of graphs.

A graphical method for breaking logical loops based on multi-tree structure

Logical loops or circular logics, interpreted as circular supporting relations among systems, remain a longstanding challenge in the probabilistic safety assessment (PSA). Logical loops are commonly found in complex industrial systems. Due to the existence of the logical loops, the minimal cut sets cannot be directly obtained. In order to solve this problem, the logical loops should be broken properly. This paper proposes a graphical method based on multi-tree structure. By constructing the simplified multi-tree, logical loops both in linearly and non-linearly interrelated systems are solved. To illustrate this method, examples of linearly interrelated systems and non-linearly interrelated systems are given in this paper. As a supplement, this method is applied to the well-known complex logical loops in the nuclear power plant. It shows that this method is highly intuitive and efficient by means of graphs.

Pilot validation of blood-based biomarkers during pregnancy and postpartum in women with prior or current depression

Major depressive disorder (MDD) is more common in women than in men, and evidence of gender-related subtypes of depression is emerging. Previously identified blood-based transcriptomic biomarkers distinguished male and female subjects with MDD from those without the disorder. In the present pilot study, we investigated the performance of these biomarkers in pregnant and postpartum women with prior major depressive episodes, some of whom had current symptomatology. The symptom scores of 13 pregnant and 15 postpartum women were identified by the Inventory of Depressive Symptoms (IDS-SR-30) at the time of blood sampling. Blood levels of the 20 transcriptomic biomarkers and that of estrogen receptor 2 (ESR2), membrane progesterone receptor alpha and beta (mPRα, mPRβ) were measured. In pregnant women, transcript levels of ADCY3, ASAH1, ATP11C, CDR2, ESR2, FAM46A, mPRβ, NAGA, RAPH1, TLR7, and ZNF291/SCAPER showed significant association with IDS-SR-30 scores, of which ADCY3, FAM46A, RAPH1, and TLR7 were identified in previous studies for their diagnostic potential for major depression. ASAH1 and ATP11C were previously also identified as potential markers of treatment efficacy. In postpartum women, transcript levels of CAT, CD59, and RAPH1 demonstrated a trend of association with IDS-SR-30 scores. Transcript levels of ADCY3, ATP11C, FAM46A, RAPH1, and ZNF291/SCAPER correlated with ESR2 and mPRβ expressions in pregnant women, whereas these associations only existed for mPRβ in postpartum women. These results suggest that a blood biomarker panel can identify depression symptomatology in pregnant women and that expression of these biomarker genes are affected by estrogen and/or progesterone binding differently during pregnancy and postpartum.

Synthetic Lethal Interaction between the ESCRT Paralog Enzymes VPS4A and VPS4B in Cancers Harboring Loss of Chromosome 18q or 16q

Few therapies target the loss of tumor suppressor genes in cancer. We examine CRISPR-SpCas9 and RNA-interference loss-of-function screens to identify new therapeutic targets associated with genomic loss of tumor suppressor genes. The endosomal sorting complexes required for transport (ESCRT) ATPases VPS4A and VPS4B score as strong synthetic lethal dependencies. VPS4A is essential in cancers harboring loss of VPS4B adjacent to SMAD4 on chromosome 18q and VPS4B is required in tumors with co-deletion of VPS4A and CDH1 (E-cadherin) on chromosome 16q. We demonstrate that more than 30% of cancers selectively require VPS4A or VPS4B. VPS4A suppression in VPS4B-deficient cells selectively leads to ESCRT-III filament accumulation, cytokinesis defects, nuclear deformation, G2/M arrest, apoptosis, and potent tumor regression. CRISPR-SpCas9 screening and integrative genomic analysis reveal other ESCRT members, regulators of abscission, and interferon signaling as modifiers of VPS4A dependency. We describe a compendium of synthetic lethal vulnerabilities and nominate VPS4A and VPS4B as high-priority therapeutic targets for cancers with 18q or 16q loss.

Neggers, Paolella, and colleagues identify the ATPases VPS4A and VPS4B as selective vulnerabilities and potential therapeutic targets in cancers harboring loss of chromosome 18q or 16q. In VPS4B-deficient cancers, VPS4A suppression leads to ESCRT-III dysfunction, nuclear deformation, and abscission defects. Moreover, ESCRT proteins and interferons can modulate dependency on VPS4A.

Abstract PO-013: MTAP protein expression is lost in nearly one-third of primary pancreatic cancers and is associated with sensitivity to MAT2A inhibition in patient-derived organoid models

Background: Deletion of chromosome region 9p21 containing CDKN2A is an early clonal event in many cancers, including pancreatic ductal adenocarcinoma (PDAC). The MTAP gene, which is directly adjacent to CDKN2A and therefore frequently co-deleted, encodes methylthioadenosine phosphorylase, a crucial enzyme in the methionine salvage pathway. Pre-clinical studies suggest that MTAP deletion can confer selective sensitivity to inhibition of the PRMT5-MAT2A axis, highlighting a potential therapeutic vulnerability for PDAC. However, comprehensive MTAP and CDKN2A biomarker data to identify patients most likely to respond to targeted inhibition are lacking. Design: We developed a quantitative, multiplex immunofluorescence (mIF) assay to jointly measure MTAP and CDKN2A protein expression at a single cell level in PDAC and applied our assay to two cohorts with extensive genomic annotation data: 1) a multi-institutional cohort of over 300 primary resected formalin-fixed paraffin-embedded PDAC specimens and 2) a cohort of 56 human patient-derived organoid samples fixed in situ and assembled into an “organoid tissue microarray.” We also conducted drug-sensitivity testing with a MAT2A inhibitor (AGI-24512) using 18 patient-derived organoids with defined MTAP and CDKN2A genomic status. Results: MTAP protein expression was completely lost in 97 (31%) of 315 primary resected tumors. Loss of MTAP was accompanied by loss of CDKN2A in 94 of 97 cases, while 3 cases showed MTAP protein loss and intact CDKN2A protein expression. An additional 108 (34%) of the 315 tumors exhibited loss of CDKN2A and intact MTAP expression. CDKN2A loss has previously been associated with reduced patient survival, but MTAP loss was not an effect modifier of this association. Within the organoid cohort, homozygous MTAP deletion was detected in 7 (13%) cases and heterozygous deletion detected in 17 (30%) cases. Organoids with homozygous MTAP deletion showed complete loss of MTAP protein expression via mIF, whereas heterozygous MTAP deletion resulted in diminished MTAP protein expression compared to MTAP wild-type organoids. In drug-sensitivity testing, 5 of 5 MTAP homozygous deleted patient-derived organoids showed increased sensitivity to MAT2A inhibition compared with MTAP wild-type or heterozygous organoid models. However, one wild-type model and one model with MTAP heterozygous deletion demonstrated comparable sensitivity to models with homozygous MTAP deletion. RNA sequencing analysis of these organoids revealed MTAP RNA levels similar to those seen in MTAP homozygous deleted organoids. Conclusion: MTAP protein expression is lost in nearly a third of primary pancreatic cancers and can be quantitated using mIF in both human tissue and organoid models. Integrative analysis of organoid mIF, DNA and RNA sequencing data suggests that MTAP deletion is the predominant, but not sole determinant of sensitivity to MAT2A inhibition with important implications for patient selection in ongoing clinical trials.

Citation Format: Sara A. Väyrynen, Annan Yang, Junning Wang, Jinming Zhang, Kristen Lowder, Kevin S. Kapner, Tim Bosse, Sri Raghavan, Andressa Dias Costa, Hannah Williams, Chen Yuan, Ashley Pelton, Vicente Morales-Oyarvide, Douglas A. Rubinson, Lauren Brais, Emma Reilly, Margaret M. Kozak, David C. Linehan, Richard F. Dunne, Daniel T. Chang, Albert C. Koong, Aram F. Hezel, Brian M. Wolpin, Jonathan A Nowak, Andrew J Aguirre. MTAP protein expression is lost in nearly one-third of primary pancreatic cancers and is associated with sensitivity to MAT2A inhibition in patient-derived organoid models [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-013.

Abstract PO-011: Synthetic lethal interaction between the ESCRT paralog enzymes VPS4A and VPS4B in SMAD4 or CDH1-deleted cancers

Somatic copy number alterations that result in loss of tumor suppressor gene function are important drivers of tumorigenesis. However, few existing therapeutic options to target oncogenic processes evoked by tumor suppressor gene inactivation exist. The discovery of synthetic lethal interactions with genetic drivers of cancer may yield new therapeutic strategies with cancer selective potential. We examined genome-scale CRISPR-SpCas9 and RNA interference screens to uncover new synthetic lethal vulnerabilities associated with the loss of common tumor suppressor genes (TSGs). The ATPases Vacuolar protein sorting 4 homolog A (VPS4A) and B (VPS4B) scored as strong synthetic lethal dependencies, with VPS4A selectively essential in cancers harboring loss of VPS4B adjacent to SMAD4 and VPS4B required in tumors with co-deletion of VPS4A and CDH1 (encoding E-cadherin). VPS4B resides 12.3 Mb away from the SMAD4 TSG on chromosome 18q and is lost in approximately 33% of all cancers, suggesting broad clinical applicability. Moreover, VPS4B is commonly lost in pancreatic cancer due to the frequent loss of SMAD4, highlighting VPS4A represents a promising target for this deadly cancer. VPS4A and VPS4B function as AAA ATPases forming a multimeric protein complex within the endosomal sorting complex required for transport (ESCRT) pathway to regulate membrane remodeling in a range of cellular processes. VPS4A suppression in cells with VPS4B/SMAD4 loss led to accumulation of ESCRT-III filaments, cytokinesis defects, nuclear deformation and micronucleation, which ultimately resulted in G2/M cell cycle arrest and apoptosis. Furthermore, upon VPS4A suppression, we observed potent in vivo tumor regression, which led to extended survival, in mouse subcutaneous xenograft models utilizing a pancreatic or rhabdomyosarcoma cancer cell line harboring VPS4B loss. CRISPR-SpCas9 screening and integrative genomic analysis revealed other ESCRT members, regulators of abscission and interferon signaling as modifiers of VPS4A dependency. Using the most comprehensive available CRISPR-SpCas9 and RNA-interference screening datasets to date, we provide a compendium of synthetic lethal vulnerabilities with TSG loss and credential VPS4A as a new and promising therapeutic target in cancers with VPS4B/SMAD4 deletion.

Citation Format: Jasper E. Neggers, Brenton R. Paolella, Adhana Asfaw, Michael V. Rothberg, Thomas A. Skipper, Radha L. Kalekar, Michael J. Krill-Burger, Neekesh V. Dharia, Guillaume Kugener, Adam D. Durbin, Annan Yang, Nancy Dumont, Yvonne Y. Li, Brian M. Wolpin, Federica Piccioni, David E. Root, Jesse S. Boehm, Andrew D. Cherniack, Aviad Tsherniak, Andrew L. Hong, William C. Hahn, Kimberly Stegmaier, Todd R. Golub, Francisca Vazquez, Andrew J. Aguirre. Synthetic lethal interaction between the ESCRT paralog enzymes VPS4A and VPS4B in SMAD4 or CDH1-deleted cancers [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-011.

Abstract LB-053: VPS4A is a synthetic lethal target in VPS4B-deficient cancers due to co-deletion with SMAD4

Somatic copy number alterations that result in loss of tumor suppressor gene function are important drivers of tumorigenesis. However, few existing therapeutic options to target oncogenic processes evoked by tumor suppressor gene inactivation exist. The discovery of synthetic lethal interactions with genetic drivers of cancer may yield new therapeutic strategies with cancer selective potential. We examined genome-scale CRISPR-SpCas9 and RNA interference screens to uncover new synthetic lethal vulnerabilities associated with the loss of common tumor suppressor genes (TSGs).

Vacuolar protein sorting 4 homolog A (VPS4A) scored as a strong, selective dependency in cancer cells with genomic loss of the SMAD4 tumor suppressor due to co-deletion of VPS4A's paralog gene, VPS4B. VPS4B resides 12.3 Mb away from the SMAD4 TSG on chromosome 18q and is lost in approximately 33% of all cancers, suggesting broad clinical applicability. VPS4A and VPS4B function as AAA ATPases forming a multimeric protein complex within the endosomal sorting complex required for transport (ESCRT) pathway to regulate membrane remodeling in a range of cellular processes. VPS4A suppression in cells with VPS4B/SMAD4 loss led to accumulation of ESCRT-III filaments, cytokinesis defects, nuclear deformation and micronucleation, which ultimately resulted in G2/M cell cycle arrest and apoptosis. Furthermore, upon VPS4A suppression, we observerd potent in vivo tumor regression, which led to extended survival, in mouse subcutaneous xenograft models with human cancer cell lines harboring VPS4B loss. Finally, genome-scale CRISPR-SpCas9 loss-of-function screening revealed other ESCRT pathway members and regulators of cellular abscission as modifiers of VPS4A dependency.

Using the most comprehensive available CRISPR-SpCas9 and RNA-interference screening datasets to date, we provide a compendium of synthetic lethal vulnerabilities with TSG loss and credential VPS4A as a new and promising therapeutic target in cancers with VPS4B/SMAD4 deletion.

Citation Format: Jasper E. Neggers, Brenton R. Paolella, Adhana Asfaw, Michael V. Rothberg, Thomas A. Skipper, Radha L. Kalekar, John M. Krill-Burger, Andrew L. Hong, Guillaume Kugener, Jeremie Kalfon, Annan Yang, Chen Yuan, Nancy Dumont, Alfredo Gonzalez, Mai Abdusamad, Yvonne Y. Li, Liam F. Spurr, Westley W. Wu, Federica Piccioni, Brian M. Wolpin, David E. Root, Jesse S. Boehm, Andrew D. Cherniack, Aviad Tsherniak, Todd R. Golub, Francisca Vazquez, Andrew J. Aguirre. VPS4A is a synthetic lethal target in VPS4B-deficient cancers due to co-deletion with SMAD4 [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-053.

Transcervical dissection of metastatic suprahyoid retropharyngeal lymph nodes from papillary thyroid carcinoma through three anatomical barriers

Papillary thyroid carcinoma (PTC) rarely metastasizes to the suprahyoid retropharyngeal lymph nodes (SRPLNs). Studies on SRPLN metastasis from PTC and a description of the dissection of the SRPLNs via the transcervical approach are rare in the literature. In this study, the cases of six patients diagnosed with PTC with SRPLN metastasis, who underwent dissection of the SRPLNs between 2001 and 2017, were reviewed retrospectively. A transcervical approach was applied for exposure and dissection of the SRPLNs in all patients. All patients were successfully treated by transcervical resection of the metastatic SRPLNs. No patient needed a mandibulotomy or presented severe complications. The median duration of follow-up after dissection of the SRPLNs was 83 months. No recurrence of SRPLN metastasis was identified during follow-up, and none of the patients died of the disease. Surgery might be the best treatment for SRPLN metastasis from PTC. The transcervical route to the retropharyngeal space is through three anatomical barriers, including the submandibular gland, the posterior belly of the digastric muscle, and the blood vessels branching from the external carotid artery and internal jugular vein. Surgical removal of metastatic SRPLNs through the transcervical approach was safe and effective.

Impact of the extent of axillary surgery in patients with N2-3 disease in the de-escalation era: a propensity score-matched study

BACKGROUND

Reduction of surgeries in axillary has been proved feasible in breast cancer with negative and limited involved axillary lymph nodes. However, for women with a heavy axillary burden, the extent of dissection is still arguable.

PATIENTS AND METHODS

From a total of 7042 patients with breast cancer who underwent surgical treatments between 2008 and 2014, 692 (9.85%) patients with the axillary staging of N2-3M0 were classified into Level I-II dissection group and Level I-III dissection group. 203 pairs of patients were matched by the propensity score.

RESULTS

The positive rate of level-III lymph nodes is 62.4% in patients who underwent Level I-III dissection. There are 67 (22.1%) patients who experienced rise in staging from N2 to N3 due to level-III dissection. With a median follow-up of 62.4 months, no significant difference was observed in RFS (P = 0.897), MFS (P = 0.610) and OS (P = 0.755) between level I-II group and level I-III group. The same results were observed in the independent analysis of neoadjuvant and non-neoadjuvant subgroups. The binary regression model showed the positivity of level-III is only associated with involved lymph nodes in level-II.

CONCLUSION

Additional level-III dissection has a limited impact on survival but still valuable in an accurate stage. The reduction of surgeries in axillary should be treated with discretion in breast cancer patients with a heavy axillary burden.

Discovery of a selective inhibitor of doublecortin like kinase 1

Doublecortin like kinase 1 (DCLK1) is an understudied kinase that is upregulated in a wide range of cancers, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about its potential as a therapeutic target. We used chemoproteomic profiling and structure-based design to develop a selective, in vivo-compatible chemical probe of the DCLK1 kinase domain, DCLK1-IN-1. We demonstrate activity of DCLK1-IN-1 against clinically relevant patient-derived PDAC organoid models and use a combination of RNA-sequencing, proteomics and phosphoproteomics analysis to reveal that DCLK1 inhibition modulates proteins and pathways associated with cell motility in this context. DCLK1-IN-1 will serve as a versatile tool to investigate DCLK1 biology and establish its role in cancer.

0532 Cognitive Behavioral Therapy Delivered Via Telemedicine vs. Face-to-Face: Results from a Randomized Controlled Non-Inferiority Trial

Introduction

Telemedicine is increasingly an option for delivery of healthcare services, but its efficacy and acceptability for delivering CBT for insomnia has not been adequately tested. In a randomized controlled non-inferiority trial, we compared face-to-face and telemedicine delivery (via the AASM SleepTM platform) of CBT for insomnia for improving sleep and daytime functioning at post-treatment and 12-week follow-up.

Methods

Sixty-five adults with chronic insomnia (46 women, mean age 47.2 ± 16.3 years) were recruited primarily from insomnia clinics and screened for disqualifying sleep, medical, and mental health disorders. Eligible participants were randomized to 6 sessions of CBT for insomnia delivered face-to-face (n=32) or via AASM SleepTM (n=33). Participants completed self-report measures of insomnia (Insomnia Severity Index, ISI) and daytime functioning (fatigue, depression, anxiety, and overall functioning) at pre-treatment, post-treatment, and 12-week follow-up. The ISI was the primary non-inferiority outcome.

Results

Telemedicine was non-inferior to face-to-face delivery of CBT for insomnia, based on a non-inferiority margin of 4 points on the ISI (β = -0.07, 95% CI -2.28 to 2.14). Compared to pre-treatment, ISI scores improved significantly at post-treatment (β = -9.02, 95% CI -10.56 to -7.47) and at 12-week follow-up (β = -9.34, 95% CI -10.89 to -7.79). Similarly, daytime functioning measures improved from pre- to post-treatment, with sustained improvements at 12-week follow-up. Scores on the fatigue scale were lower in the telemedicine group at both post-treatment (F=4.64, df=1,119, p&lt;.03) and follow-up (F=5.79, df=1,119, p&lt;.02).

Conclusion

Insomnia and daytime functioning improve similarly whether CBT for insomnia is delivered via telemedicine or face-to-face. Telemedicine delivery of CBT for insomnia should be implemented more systematically to improve access to this evidence-based treatment.

Support

American Sleep Medicine Foundation Grant # 168-SR-17 (JT Arnedt, PhD)

0513 Comparison of Patient Satisfaction and Therapeutic Alliance for Telemedicine vs. Face-to-Face Delivered Cognitive Behavioral Therapy for Insomnia

Introduction

CBT for insomnia (CBTI) is effective but a barrier to its widespread use is the lack of evidence-based delivery modalities other than face-to-face. The perception and acceptability of telemedicine for the delivery of CBTI is unknown. We conducted a randomized controlled non-inferiority trial comparing face-to-face (F2F) and telemedicine (via AASM SleepTM) delivery of CBTI. We compared measures of patient satisfaction with treatment and the perception of the therapist’s warmth and skills between F2F and SleepTM.

Methods

Adults with insomnia were recruited from insomnia clinics and the community and screened for sleep, medical, and mental health disorders. Eligible participants were randomized to receive CBTI either via AASM SleepTM or F2F in 6 weekly sessions of 45-60 minutes each. Participants completed the Client Satisfaction Questionnaire (CSQ-8) and The Therapy Evaluation Questionnaire (TEQ) after completing treatment. The CSQ-8 score ranges from 8-32 with high scores indicating greater satisfaction. We also analyzed the two items on the TEQ that assess participants’ perception of therapist’s warmth and skills. Item scores ranged from 1-7, with higher scores indicating greater warmth and skills.

Results

Sixty-five adults with chronic insomnia were recruited primarily from insomnia clinics. Sixty-two participants (41 women, mean age 48.9 ± 15.4 years) completed all 6 sessions of CBTI via F2F (n=32) or via AASM SleepTM (n=30). Independent samples t-tests revealed no significant differences between conditions on patient satisfaction (SleepTM, 28.5 +/-4.2 vs F2F 29.9 +/-2.4, t(-1.5), p=.14), therapist warmth (SleepTM, 6.0 ±1.1 vs F2F, 6.4±0.95, t(-1.4), p=.16), or therapist skills (Sleep TM 6.4 ±1.0 vs F2F, 6.7±0.59, t(-1.5), p=.15).

Conclusion

Our findings suggest no differences in patient satisfaction, perception of therapist’s warmth, or confidence in therapist’s skills between telemedicine (via the AASM SleepTM) and F2F delivery of CBTI. Telemedicine-delivered CBTI should be implemented more widely.

Support

Research supported by American Sleep Medicine Foundation Grant # 168-SR-17 (JT Arnedt)

Singlet Pathway to the Ground State of Ultracold Polar Molecules

Starting from weakly bound Feshbach molecules, we demonstrate a two-photon pathway to the dipolar ground state of bi-alkali molecules that involves only singlet-to-singlet optical transitions. This pathway eliminates the search for a suitable intermediate state with sufficient singlet-triplet mixing and the exploration of its hyperfine structure, as is typical for pathways starting from triplet dominated Feshbach molecules. By selecting a Feshbach state with a stretched singlet hyperfine component and controlling the laser polarizations, we assure coupling to only single hyperfine components of the A^{1}Σ^{+} excited potential and the X^{1}Σ^{+} rovibrational ground state. In this way an ideal three level system is established, even if the hyperfine structure is not resolved. We demonstrate this pathway with ^{6}Li^{40}K molecules, and discuss its application to other important molecular species.

Structure-Based Design of a Potent and Selective Covalent Inhibitor for SRC Kinase That Targets a P-Loop Cysteine

SRC is a major regulator of many signaling pathways and contributes to cancer development. However, development of a selective SRC inhibitor has been challenging, and FDA-approved SRC inhibitors, dasatinib and bosutinib, are multitargeted kinase inhibitors. Here, we describe our efforts to develop a selective SRC covalent inhibitor by targeting cysteine 277 on the P-loop of SRC. Using a promiscuous covalent kinase inhibitor (CKI) SM1-71 as a starting point, we developed covalent inhibitor 15a, which discriminates SRC from other covalent targets of SM1-71 including TAK1 and FGFR1. As an irreversible covalent inhibitor, compound 15a exhibited sustained inhibition of SRC signaling both in vitro and in vivo. Moreover, 15a exhibited potent antiproliferative effects in nonsmall cell lung cancer cell lines harboring SRC activation, thus providing evidence that this approach may be promising for further drug development efforts.

CDK7 Inhibition Potentiates Genome Instability Triggering Anti-tumor Immunity in Small Cell Lung Cancer

Cyclin-dependent kinase 7 (CDK7) is a central regulator of the cell cycle and gene transcription. However, little is known about its impact on genomic instability and cancer immunity. Using a selective CDK7 inhibitor, YKL-5-124, we demonstrated that CDK7 inhibition predominately disrupts cell-cycle progression and induces DNA replication stress and genome instability in small cell lung cancer (SCLC) while simultaneously triggering immune-response signaling. These tumor-intrinsic events provoke a robust immune surveillance program elicited by T cells, which is further enhanced by the addition of immune-checkpoint blockade. Combining YKL-5-124 with anti-PD-1 offers significant survival benefit in multiple highly aggressive murine models of SCLC, providing a rationale for new combination regimens consisting of CDK7 inhibitors and immunotherapies.

Validation of the BIOCHIP test for the diagnosis of bullous pemphigoid, pemphigus vulgaris and pemphigus foliaceus

BACKGROUND

The BIOCHIP is a novel multiplex indirect immunofluorescence technique used in the serological diagnosis of bullous pemphigoid and pemphigus. The BIOCHIP method combines the screening of autoantibodies and target antigen-specific substrates in a single miniature incubation field.

OBJECTIVE

To evaluate the diagnostic accuracy of the new immunofluorescence BIOCHIP multiplex tool in pemphigus and bullous pemphigoid.

METHODS

For the validation of the BIOCHIP, sera from patients with BP (n = 38), PF (n = 8) and pemphigus vulgaris (PV) (n = 23) were used. In addition, sera from disease control patients (n = 63) and healthy volunteers (n = 39) were used. The multiplex BIOCHIP and direct immunofluorescence (DIF) were performed for all BP, PF and PV patients. Additional indirect immunofluorescence (IIF) was performed on patients with BP, and ELISA was performed on patients with pemphigus.

RESULTS

The BIOCHIP mosaic showed a sensitivity of 86.8% and specificity of 85% for BP180 or BP230 being positive in BP. It demonstrated a sensitivity of 75% and specificity of 97.7% for Dsg1 in PF. The BIOCHIP was found to have a sensitivity of 60.9% and specificity of 73.6% for Dsg3 in PV.

CONCLUSION

The BIOCHIP mosaic-based immunofluorescence test is potentially a simple, time and effort saving test that can aid in the diagnosis and screening of BP, PV and PF. However, there is potential for interpretation bias and a learning curve that needs to be taken into consideration.

Single and Dual Targeting of Mutant EGFR with an Allosteric Inhibitor

Allosteric kinase inhibitors offer a potentially complementary therapeutic strategy to ATP-competitive kinase inhibitors due to their distinct sites of target binding. In this study, we identify and study a mutant-selective EGFR allosteric inhibitor, JBJ-04-125-02, which as a single agent can inhibit cell proliferation and EGFR^{L858R/T790M/C797S} signaling in vitro and in vivo. However, increased EGFR dimer formation limits treatment efficacy and leads to drug resistance. Remarkably, osimertinib, an ATP-competitive covalent EGFR inhibitor, uniquely and significantly enhances the binding of JBJ-04-125-02 for mutant EGFR. The combination of osimertinib and JBJ-04-125-02 results in an increase in apoptosis, a more effective inhibition of cellular growth, and an increased efficacy in vitro and in vivo compared with either single agent alone. Collectively, our findings suggest that the combination of a covalent mutant-selective ATP-competitive inhibitor and an allosteric EGFR inhibitor may be an effective therapeutic approach for patients with EGFR-mutant lung cancer. SIGNIFICANCE: The clinical efficacy of EGFR tyrosine kinase inhibitors (TKI) in EGFR-mutant lung cancer is limited by acquired drug resistance, thus highlighting the need for alternative strategies to inhibit EGFR. Here, we identify a mutant EGFR allosteric inhibitor that is effective as a single agent and in combination with the EGFR TKI osimertinib.This article is highlighted in the In This Issue feature, p. 813.

PTBP1 enhances exon11a skipping in Mena pre-mRNA to promote migration and invasion in lung carcinoma cells

Alternative splicing (AS) events occur in the majority of human genes. AS in a single gene can give rise to different functions among multiple isoforms. Human ortholog of mammalian enabled (Mena) is a conserved regulator of actin dynamics that plays an important role in metastasis. Mena has been shown to have multiple splice variants in human tumor cells due to AS. However, the mechanism mediated Mena AS has not been elucidated. Here we showed that polypyrimidine tract-binding protein 1 (PTBP1) could modulate Mena AS. First, PTBP1 levels were elevated in metastatic lung cancer cells as well as during epithelial-mesenchymal transition (EMT) process. Then, knockdown of PTBP1 using shRNA inhibited migration and invasion of lung carcinoma cells and decreased the Mena exon11a skipping, whereas overexpression of PTBP1 had the opposite effects. The results of RNA pull-down assays and mutation analyses demonstrated that PTBP1 functionally targeted and physically interacted with polypyrimidine sequences on both upstream intron11 (TTTTCCCCTT) and downstream intron11a (TTTTTTTTTCTTT). In addition, the results of migration and invasion assays as well as detection of filopodia revealed that the effect of PTBP1 was reversed by knockdown of Mena but not Mena11a+. Overexpressed MenaΔ11a also rescued the PTBP1-induced migration and invasion. Taken together, our study provides a novel mechanism that PTBP1 modulates Mena exon11a skipping, and indicates that PTBP1 depends on the level of Mena11a- to promote lung cancer cells migration and invasion. The regulation of Mena AS may be a potential prognostic marker and a promising target for treatment of lung carcinoma.