Low-dose pegylated recombinant human granulocyte-colony stimulating factor as hematopoietic support for adjuvant chemotherapy in Chinese patients with breast cancer: An open-label, randomized, non-inferiority trial.

AIMS: The recommended dosage of pegylated recombinant human granulocyte-colony stimulating factor (PEG-rhG-CSF) for Western chemotherapy patients is 6 mg per cycle. However, for Eastern Asians, the optimal dose remains unknown. METHODS: This open-label, randomized, non-inferiority trial (NCT05283616) enrolled Chinese female breast cancer patients receiving adjuvant chemotherapy. Participants were randomized to receive either 3 or 6 mg of PEG-rhG-CSF per cycle, stratified by body weight (BW; ≤60 kg vs. >60 kg). The primary endpoint was timely absolute neutrophil count (ANC) recovery before the second cycle of chemotherapy. RESULTS: A total of 122 patients were randomized and 116 were included for efficacy analyses. The timely ANC recovery rate in the 3 mg arm was 89.8%, compared to 93.0% in the 6 mg arm (one-sided 95% confidence interval [CI] lower limit for difference: -11.7%), meeting the prespecified non-inferiority margin of 15%. The rate was 93.3% with PEG-rhG-CSF 3 mg and 96.6% with 6 mg in patients with BW ≤ 60 kg, and 86.2% and 89.3%, respectively, in those with BW > 60 kg. Although the incidence of severe neutropenia was similar across arms, the occurrence of excessively high ANC and white blood cell counts was higher in the 6 mg arm. No grade ≥3 adverse events related to PEG-rhG-CSF occurred. CONCLUSION: Three milligrams of PEG-rhG-CSF per cycle provided non-inferior neutrophil protection and attenuated neutrophil overshoot compared to 6 mg doses. This low-dose regimen could be a new supportive care option for Chinese breast cancer patients receiving anthracycline-based adjuvant chemotherapy.

G protein subunit alpha i2's pivotal role in angiogenesis.

Here we explored the potential role of Gαi2 (G protein subunit alpha i2) in endothelial cell function and angiogenesis. Methods: Genetic methodologies such as shRNA, CRISPR/Cas9, dominant negative mutation, and overexpression were utilized to modify Gαi2 expression or regulate its function. Their effects on endothelial cell functions were assessed in vitro. In vivo, the endothelial-specific Gαi2 shRNA adeno-associated virus (AAV) was utilized to silence Gαi2 expression. The impact of this suppression on retinal angiogenesis in control mice and streptozotocin (STZ)-induced diabetic retinopathy (DR) mice was analyzed. Results: Analysis of single-cell RNA sequencing data revealed Gαi2 (GNAI2) was predominantly expressed in retinal endothelial cells and expression was increased in retinal endothelial cells following oxygen-induced retinopathy (OIR) in mice. Moreover, transcriptome analysis linking Gαi2 to angiogenesis-related processes/pathways, supported by increased Gαi2 expression in experimental OIR mouse retinas, highlighted its possible role in angiogenesis. In various endothelial cell types, shRNA-induced silencing and CRISPR/Cas9-mediated knockout (KO) of Gαi2 resulted in substantial reductions in cell proliferation, migration, invasion, and capillary tube formation. Conversely, Gαi2 over-expression in endothelial cells induced pro-angiogenic activities, enhancing cell proliferation, migration, invasion, and capillary tube formation. Furthermore, our investigation revealed a crucial role of Gαi2 in NFAT (nuclear factor of activated T cells) activation, as evidenced by the down-regulation of NFAT-luciferase reporter activity and pro-angiogenesis NFAT-targeted genes (Egr3, CXCR7, and RND1) in Gαi2-silenced or -KO HUVECs, which were up-regulated in Gαi2-overexpressing endothelial cells. Expression of a dominant negative Gαi2 mutation (S48C) also down-regulated NFAT-targeted genes, slowing proliferation, migration, invasion, and capillary tube formation in HUVECs. Importantly, in vivo experiments revealed that endothelial Gαi2 knockdown inhibited retinal angiogenesis in mice, with a concomitant down-regulation of NFAT-targeted genes in mouse retinal tissue. In contrast, Gαi2 over-expression in endothelial cells enhanced retinal angiogenesis in mice. Single-cell RNA sequencing data confirmed increased levels of Gαi2 specifically in retinal endothelial cells of mice with streptozotocin (STZ)-induced diabetic retinopathy (DR). Importantly, endothelial Gαi2 silencing ameliorated retinal pathological angiogenesis in DR mice. Conclusion: Our study highlights a critical role for Gαi2 in NFAT activation, endothelial cell activation and angiogenesis, offering valuable insights into potential therapeutic strategies for modulating these processes.

Clinical features, prognostic stratification, and treatment of advanced-stage non-nasal type extranodal natural killer/T-cell lymphoma: a multi-institutional real-world study.

The present study aimed to investigate the clinical features, prognosis, and treatment of advanced-stage non-nasal type extranodal natural killer/T-cell lymphoma (ENKTCL). This real-world study retrospectively reviewed 56 newly diagnosed advanced-stage non-nasal type ENKTCL patients from two large-scale Chinese cancer centers in the last 10-15 years and screened 139 newly diagnosed advanced-stage nasal type ENKTCLs admitted during the same period for comparison. The non-nasal type ENKTCLs exhibited significantly higher Ki-67 expression levels compared to nasal type disease (P = 0.011). With a median follow-up duration of 75.03 months, the non-nasal group showed slightly inferior survival outcomes without statistically significant differences compared to the nasal group (median overall survival (OS): 14.57 vs. 21.53 months, 5-year OS: 28.0% vs. 38.5%, P = 0.120). Eastern Cooperative Oncology Group (ECOG) score ≥ 2 (hazard ratio (HR) = 2.18, P = 0.039) and lactic dehydrogenase (LDH) elevation (HR = 2.44, P = 0.012) were significantly correlated with worse OS in the non-nasal group. First-line gemcitabine-based chemotherapy regimens showed a trend toward slightly improved efficacy and survival outcomes compared to non-gemcitabine-based ones in the present cohort of non-nasal ENKTCLs (objective response rate: 91.7% vs. 63.6%, P = 0.144; complete response rate: 50.0% vs. 33.3%, P = 0.502; median progression-free survival: 10.43 vs. 3.40 months, P = 0.106; median OS: 25.13 vs. 9.30 months, P = 0.125), which requires further validation in larger sample size studies. Advanced-stage non-nasal type patients could achieve comparable prognosis with nasal cases after rational therapy. The modified nomogram-revised index (including age, ECOG score, and LDH) and modified international prognostic index (including age, ECOG score, LDH, and number of extranodal involvement) functioned effectively for prognostic stratification in non-nasal type ENKTCLs.

Treatment and prognosis of newly diagnosed advanced-stage extranodal natural killer / T cell lymphoma: a single-center real-world study across two decades.

INTRODUCTION: Although there is now a consensus on asparaginase-based chemotherapy regimens in treatment of advanced-stage extranodal natural killer / T cell lymphomas (ENKTCLs), patient survival in the real-world setting is still not optimistic according to previous literature reports, and the optimal chemotherapeutic regimens and integration of different therapeutic methods under the concept of combined-modality treatment still need to be further explored and verified. METHODS: Newly diagnosed stage Ⅲ / Ⅳ ENKTCL patients from Chinese National Cancer Center in the last two decades were retrospectively collected and analyzed. Overall survival (OS) and progression-free survival (PFS) were determined as primary endpoints. Log-rank tests and Cox proportional hazard models were performed to test for survival differences between subgroups and examine the univariable and multivariable associations. RESULTS: The study included 83 newly diagnosed stage Ⅲ / Ⅳ ENKTCL patients and reported a median OS of 26.07 months and an estimated 5-year OS of 41.3% with a median follow-up of 82.13 months. First-line asparaginase- compared to non-asparaginase-based regimens significantly prolonged PFS (P=0.007; HR=0.48, P=0.020) and showed a tendency to improve OS (P=0.064; HR=0.74, P=0.359). Gemcitabine-based regimens also exhibited a trend towards improved PFS (P=0.048; HR=0.59, P=0.164) and OS (P=0.008; HR=0.67, P=0.282) compared to non-gemcitabine-based ones. The asparaginase and gemcitabine combinations yielded a 5-year OS of 55.0% and led to significantly superior PFS (P=0.020; HR=0.40, P=0.022) and slightly better OS (P=0.054; HR=0.79, P=0.495) compared to the remaining regimens. First-line combined-modality treatment integrating chemotherapy and radiotherapy improved PFS (P=0.051) and OS (P=0.036) compared to chemotherapy alone. Four autologous hematopoietic stem cell transplantation recipients reached a median OS of 58.34 months. CONCLUSION: Asparaginase and gemcitabine alone brought favorable impact on PFS and OS; and the asparaginase and gemcitabine combination chemotherapy yielded the optimal efficacy, response duration and survival outcomes. Combined-modality treatment including potent chemotherapy supplemented by radiotherapy and/or consolidative transplantation could improve prognosis in newly diagnosed advanced-stage ENKTCLs.

Intensive therapy can improve long-term survival in newly diagnosed, advanced-stage extranodal NK/T-cell lymphoma: A multi-institutional, real-world study.

The study investigated the treatment and prognosis of advanced-stage extranodal natural killer/T-cell lymphoma (ENKTL). With a median follow-up of 75.03 months, the median overall survival (mOS) for the 195 newly diagnosed stage III/IV ENKTL patients was 19.43 months, and estimated 1-, 2-, 3- and 5-year OS were 59.5%, 46.3%, 41.8% and 35.1%, respectively. Chemotherapy (CT) + radiotherapy (RT) compared to CT alone (P = .007), and hematopoietic stem cell transplantation (HSCT) compared to non-HSCT (P < .001), both improved OS. For patients ≤60 years and ineligible for HSCT, other therapies with complete remission led to comparable OS (P = .141). Nine patients ever treated with chidamide achieved a median progression-free survival (mPFS) and mOS of 53.63 (range, 3.47-92.33) and 54.80 (range, 5.50-95.70) months, and four with chidamide maintenance therapy (MT) achieved a mPFS and mOS of 55.83 (range, 53.27-92.33) and 60.65 (range, 53.70-95.70) months, possibly providing an alternative option for non-HSCT patients. Non-anthracycline (ANT)- compared to ANT-, asparaginase (Aspa)- compared to non-Aspa- and gemcitabine (Gem)- compared to non-Gem-based regimens, prolonged PFS (P = .031; P = .005; P = .009) and OS (P = .010; P = .086; P = .003), respectively. Multivariate analysis demonstrated that Gem-based regimens improved PFS (HR = 0.691, P = .061) and OS (HR = 0.624, P = .037). Gem + Aspa combinations slightly improved PFS and OS compared to regimens containing Gem or Aspa alone (P > 0.05). First-line "intensive therapy," including CT (particularly Gem + Aspa regimens), RT, HSCT and alternative chidamide MT, was proposed and could improve long-term survival for advanced-stage ENKTLs. Ongoing prospective clinical studies may shed further light on the value of chidamide MT.

Efficiency and safety analysis of Plerixafor combined with granulocyte colony-stimulating factor on autologous hematopoietic stem cell mobilization in lymphoma / 中华血液学杂志

Objective: To evaluate the advantages and safety of Plerixafor in combination with granulocyte colony-stimulating factor (G-CSF) in autologous hematopoietic stem cell mobilization of lymphoma. Methods: Lymphoma patients who received autologous hematopoietic stem cell mobilization with Plerixafor in combination with G-CSF or G-CSF alone were obtained. The clinical data, the success rate of stem cell collection, hematopoietic reconstitution, and treatment-related adverse reactions between the two groups were evaluated retrospectively. Results: A total of 184 lymphoma patients were included in this analysis, including 115 cases of diffuse large B-cell lymphoma (62.5%) , 16 cases of classical Hodgkin's lymphoma (8.7%) , 11 cases of follicular non-Hodgkin's lymphoma (6.0%) , 10 cases of angioimmunoblastic T-cell lymphoma (5.4%) , 6 cases of mantle cell lymphoma (3.3%) , and 6 cases of anaplastic large cell lymphoma (3.3%) , 6 cases of NK/T-cell lymphoma (3.3%) , 4 cases of Burkitt's lymphoma (2.2%) , 8 cases of other types of B-cell lymphoma (4.3%) , and 2 cases of other types of T-cell lymphoma (1.1%) ; 31 patients had received radiotherapy (16.8%) . The patients in the two groups were recruited with Plerixafor in combination with G-CSF or G-CSF alone. The baseline clinical characteristics of the two groups were basically similar. The patients in the Plerixafor in combination with the G-CSF mobilization group were older, and the number of recurrences and third-line chemotherapy was higher. 100 patients were mobilized with G-CSF alone. The success rate of the collection was 74.0% for one day and 89.0% for two days. 84 patients in the group of Plerixafor combined with G-CSF were recruited successfully with 85.7% for one day and 97.6% for two days. The success rate of mobilization in the group of Plerixafor combined with G-CSF was substantially higher than that in the group of G-CSF alone (P=0.023) . The median number of CD34(+) cells obtained in the mobilization group of Plerixafor combined with G-CSF was 3.9×10(6)/kg. The median number of CD34(+) cells obtained in the G-CSF Mobilization group alone was 3.2×10(6)/kg. The number of CD34(+) cells collected by Plerixafor combined with G-CSF was considerably higher than that in G-CSF alone (P=0.001) . The prevalent adverse reactions in the group of Plerixafor combined with G-CSF were grade 1-2 gastrointestinal reactions (31.2%) and local skin redness (2.4%) . Conclusion: The success rate of autologous hematopoietic stem cell mobilization in lymphoma patients treated with Plerixafor combined with G-CSF is significantly high. The success rate of collection and the absolute count of CD34(+) stem cells were substantially higher than those in the group treated with G-CSF alone. Even in older patients, second-line collection, recurrence, or multiple chemotherapies, the combined mobilization method also has a high success rate of mobilization.

SIK2 inhibition enhances PARP inhibitor activity synergistically in ovarian and triple-negative breast cancers.

Poly(ADP-ribose) polymerase inhibitors (PARP inhibitors) have had an increasing role in the treatment of ovarian and breast cancers. PARP inhibitors are selectively active in cells with homologous recombination DNA repair deficiency caused by mutations in BRCA1/2 and other DNA repair pathway genes. Cancers with homologous recombination DNA repair proficiency respond poorly to PARP inhibitors. Cancers that initially respond to PARP inhibitors eventually develop drug resistance. We have identified salt-inducible kinase 2 (SIK2) inhibitors, ARN3236 and ARN3261, which decreased DNA double-strand break (DSB) repair functions and produced synthetic lethality with multiple PARP inhibitors in both homologous recombination DNA repair deficiency and proficiency cancer cells. SIK2 is required for centrosome splitting and PI3K activation and regulates cancer cell proliferation, metastasis, and sensitivity to chemotherapy. Here, we showed that SIK2 inhibitors sensitized ovarian and triple-negative breast cancer (TNBC) cells and xenografts to PARP inhibitors. SIK2 inhibitors decreased PARP enzyme activity and phosphorylation of class-IIa histone deacetylases (HDAC4/5/7). Furthermore, SIK2 inhibitors abolished class-IIa HDAC4/5/7-associated transcriptional activity of myocyte enhancer factor-2D (MEF2D), decreasing MEF2D binding to regulatory regions with high chromatin accessibility in FANCD2, EXO1, and XRCC4 genes, resulting in repression of their functions in the DNA DSB repair pathway. The combination of PARP inhibitors and SIK2 inhibitors provides a therapeutic strategy to enhance PARP inhibitor sensitivity for ovarian cancer and TNBC.

Targeting CD123 in blastic plasmacytoid dendritic cell neoplasm using allogeneic anti-CD123 CAR T cells.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with poor outcomes with conventional therapy. Nearly 100% of BPDCNs overexpress interleukin 3 receptor subunit alpha (CD123). Given that CD123 is differentially expressed on the surface of BPDCN cells, it has emerged as an attractive therapeutic target. UCART123 is an investigational product consisting of allogeneic T cells expressing an anti-CD123 chimeric antigen receptor (CAR), edited with TALEN® nucleases. In this study, we examine the antitumor activity of UCART123 in preclinical models of BPDCN. We report that UCART123 have selective antitumor activity against CD123-positive primary BPDCN samples (while sparing normal hematopoietic progenitor cells) in the in vitro cytotoxicity and T cell degranulation assays; supported by the increased secretion of IFNγ by UCART123 cells when cultured in the presence of BPDCN cells. UCART123 eradicate BPDCN and result in long-term disease-free survival in a subset of primary patient-derived BPDCN xenograft mouse models. One potential challenge of CD123 targeting therapies is the loss of CD123 antigen through diverse genetic mechanisms, an event observed in one of three BPDCN PDX studied. In summary, these results provide a preclinical proof-of-principle that allogeneic UCART123 cells have potent anti-BPDCN activity.

Evading immune surveillance via tyrosine phosphorylation of nuclear PCNA.

Increased DNA replication and metastasis are hallmarks of cancer progression, while deregulated proliferation often triggers sustained replication stresses in cancer cells. How cancer cells overcome the growth stress and proceed to metastasis remains largely elusive. Proliferating cell nuclear antigen (PCNA) is an indispensable component of the DNA replication machinery. Here, we show that phosphorylation of PCNA on tyrosine 211 (pY211-PCNA) regulates DNA metabolism and tumor microenvironment. Abrogation of pY211-PCNA blocks fork processivity, resulting in biogenesis of single-stranded DNA (ssDNA) through a MRE11-dependent mechanism. The cytosolic ssDNA subsequently induces inflammatory cytokines through a cyclic GMP-AMP synthetase (cGAS)-dependent cascade, triggering an anti-tumor immunity by natural killer (NK) cells to suppress distant metastasis. Expression of pY211-PCNA is inversely correlated with cytosolic ssDNA and associated with poor survival in patients with cancer. Our results pave the way to biomarkers and therapies exploiting immune responsiveness to target metastatic cancer.

Strategy for Achieving Long-Wavelength Near-Infrared Luminescence of Diimineplatinum(II) Complexes.

Although many strategies have been used to help design effective near-infrared (NIR) luminescent materials, it is still a huge challenge to realize long-wavelength NIR luminescence of diimineplatinum(II) complexes in the solid state. Herein, we have successfully achieved long-wavelength NIR luminescence of a family of diimineplatinum(II) complexes based on a new strategy that combines a one-dimensional (1D) "Pt wire" structure with the electronic effect of the substituent. The structures of six solvated diimineplatinum(II) complexes based on 4,4-dichloro-2,2'-bipyridine or 4,4-dibromo-2,2'-bipyridine and 4-substituted phenylacetylene ligands have been determined, namely, 1·1/2toluene, 2·1/2THF, 3·1/8toluene, 4·1/2THF, 5·1/8CH2Cl2, and 6·1/4toluene. All of them crystallize in the monoclinic space group C2/c or C2/m and stack in the 1D "Pt wire" structure. In the solid state, six complexes exhibited unusual long-wavelength metal-metal-to-ligand charge-transfer luminescence that peaked at 984, 1044, 972, 990, 1022, and 935 nm, respectively. Interestingly, 2·1/2THF has the shortest Pt···Pt distance and the longest emission wavelength among the six complexes. As far as we know, the luminescence of 2·1/2THF at 1044 nm is the longest emission wavelength among known diimineplatinum(II) complexes. Systematic studies revealed that good molecular planarity, suitable substituent position, weak hydrogen-bond-forming ability of the substituents, appropriate molecular bending, and weakening of the interaction between solvated molecules and platinum molecules are conducive to the construction of a 1D "Pt wire" structure of the diimineplatinum(II) complex. Furthermore, the emission energy of the complex is mainly determined by the strength of the Pt-Pt interaction and electronic effect of the substituent.

Photoinduced Copper-Catalyzed Site-Selective C(sp2)-C(sp) Cross-Coupling via Aryl Sulfonium Salts.

The classical Sonogashira reaction of aryl electrophiles in the presence of Pd catalysts has been well established as a potent method for arylalkyne synthesis. However, the site-selective C(sp2)-C(sp) cross-coupling strategy using a non-noble-metal catalyst is rare. An efficient alternative approach for the synthesis of arylalkynes via a Cu-catalyzed Sonogashira-type reaction promoted by visible light is described. This method enables site-selective alkynylation from aryl sulfonium salts derived from diverse arenes to a set of arylalkynes with high selectivity and high functional-group compatibility. Moreover, rapid alkynylation of drug molecules is demonstrated.

Effect of breast tissue marker on MRI evaluation for breast lesions and clinical significance / 中国医师杂志

Objective:This study compares the magnetic resonance imaging (MRI) appearance of two types of breast tissue markers to investigate the appropriate clinical application of the markers.Methods:Breast MRI of 69 patients (78 masses) with breast tissue markers had been placed were analyzed retrospectively from November 2015 to August 2018 in our hospital. The sizes and shapes of breast tissue markers were assessed in axial fat-suppressed T2-weighted images, T1-weighted images and contrast-enhanced T1-weighed images.Results:The length of the coil nickel-free stainless steel markers were greater than ribbon titanium markers, with statistical difference in fat-suppressed T2-weighted images ( P=0.039). In contrast-enhanced T1-weighted images, all coil nickel-free stainless steel markers showed >6 mm diameter and round shape, and ribbon titanium markers showed >6 mm diameter ( n=20) or ≤6 mm diameter ( n=8), and round ( n=20), dot ( n=7) or band ( n=1) shapes. The categories of sizes and shapes in two types of breast tissue markers both had statistical significance ( P<0.001, P<0.001). Conclusions:Small breast lesions with breast tissue markers are not suitable for MRI evaluation. The artifact of ribbon titanium markers is smaller than coil nickel-free stainless steel markers, so they have less impact for lesions. The choice of the breast tissue markers and image evaluation methods should depend on the different clinical conditions.

Neutrophils Promote Amphiregulin Production in Intestinal Epithelial Cells through TGF-ß and Contribute to Intestinal Homeostasis.

Neutrophils are the first responders to sites of inflammation when the intestinal epithelial barrier is breached and the gut microbiota invade. Despite current efforts in understanding the role of neutrophils in intestinal homeostasis, the complex interactions between neutrophils and intestinal epithelial cells (IECs) is still not well characterized. In this study, we demonstrated that neutrophils enhanced production of amphiregulin (AREG), a member of the EGFR ligand family, by IECs, which promoted IEC barrier function and tissue repair. Depletion of neutrophils resulted in more severe colitis in mice because of decreased AREG production by IECs upon dextran sodium sulfate (DSS) insult. Administration of AREG restored epithelial barrier function and ameliorated colitis. Furthermore, neutrophil-derived TGF-ß promoted AREG production by IECs. Mechanistically, TGF-ß activated MEK1/2 signaling, and inhibition of MEK1/2 abrogated TGF-ß-induced AREG production by IECs. Collectively, these findings reveal that neutrophils play an important role in the maintenance of IEC barrier function and homeostasis.

Author Correction: Mutations in the SWI/SNF complex induce a targetable dependence on oxidative phosphorylation in lung cancer.

In the version of this article originally published, information regarding several funding sources was omitted from the Acknowledgements section. The following sentences should have been included: "This work was supported by the generous philanthropic contributions to The University of Texas MD Anderson Lung Cancer Moon Shots Program, the UT Lung SPORE 5 P50 CA07090, and the MD Anderson Cancer Center Support Grant P30CA01667. V.P is supported by R01CA155196-01A1 from the National Cancer Institute." Also, reference 18 was incorrect. The original reference was: Kim, E. S. et al. The BATTLE trial: personalizing therapy for lung cancer. Cancer Discov. 1, 44-53 (2011). It should have been: Papadimitrakopoulou, V. et al. The BATTLE-2 study: a biomarker-integrated targeted therapy study in previously treated patients with advanced non-small-cell lung cancer. J Clin. Oncol. 34, 3638-3647 (2016). The errors have been corrected in the HTML and PDF versions of this article.

Mutations in the SWI/SNF complex induce a targetable dependence on oxidative phosphorylation in lung cancer.

Lung cancer is a devastating disease that remains a top cause of cancer mortality. Despite improvements with targeted and immunotherapies, the majority of patients with lung cancer lack effective therapies, underscoring the need for additional treatment approaches. Genomic studies have identified frequent alterations in components of the SWI/SNF chromatin remodeling complex including SMARCA4 and ARID1A. To understand the mechanisms of tumorigenesis driven by mutations in this complex, we developed a genetically engineered mouse model of lung adenocarcinoma by ablating Smarca4 in the lung epithelium. We demonstrate that Smarca4 acts as a bona fide tumor suppressor and cooperates with p53 loss and Kras activation. Gene expression analyses revealed the signature of enhanced oxidative phosphorylation (OXPHOS) in SMARCA4 mutant tumors. We further show that SMARCA4 mutant cells have enhanced oxygen consumption and increased respiratory capacity. Importantly, SMARCA4 mutant lung cancer cell lines and xenograft tumors have marked sensitivity to inhibition of OXPHOS by a novel small molecule, IACS-010759, that is under clinical development. Mechanistically, we show that SMARCA4-deficient cells have a blunted transcriptional response to energy stress creating a therapeutically exploitable synthetic lethal interaction. These findings provide the mechanistic basis for further development of OXPHOS inhibitors as therapeutics against SWI/SNF mutant tumors.

Clinically relevant inflammatory breast cancer patient-derived xenograft-derived ex vivo model for evaluation of tumor-specific therapies.

Inflammatory breast cancer (IBC) is a rare and aggressive presentation of invasive breast cancer with a 62% to 68% 5-year survival rate. It is the most lethal form of breast cancer, and early recognition and treatment is important for patient survival. Like non-inflammatory breast cancer, IBC comprises multiple subtypes, with the triple-negative subtype being overrepresented. Although the current multimodality treatment regime of anthracycline- and taxane-based neoadjuvant therapy, surgery, and radiotherapy has improved the outcome of patients with triple-negative IBC, overall survival continues to be worse than in patients with non-inflammatory locally advanced breast cancer. Translation of new therapies into the clinics to successfully treat IBC has been poor, in part because of the lack of in vitro preclinical models that can accurately predict the response of the original tumor to therapy. We report the generation of a preclinical IBC patient-derived xenograft (PDX)-derived ex vivo (PDXEx) model and show that it closely replicates the tissue architecture of the original PDX tumor harvested from mice. The gene expression profile of our IBC PDXEx model had a high degree of correlation to that of the original tumor. This suggests that the process of generating the PDXEx model did not significantly alter the molecular signature of the original tumor. We demonstrate a high degree of similarity in drug response profile between a PDX mouse model and our PDXEx model generated from the same original PDX tumor tissue and treated with the same panel of drugs, indicating that our PDXEx model had high predictive value in identifying effective tumor-specific therapies. Finally, we used our PDXEx model as a platform for a robotic-based high-throughput drug screen of a 386-drug anti-cancer compound library. The top candidates identified from this drug screen all demonstrated greater therapeutic efficacy than the standard-of-care drugs used in the clinic to treat triple-negative IBC, doxorubicin and paclitaxel. Our PDXEx model is simple, and we are confident that it can be incorporated into a PDX mouse system for use as a first-pass screening platform. This will permit the identification of effective tumor-specific therapies with high predictive value in a resource-, time-, and cost-efficient manner.