Non-apoptotic caspase activation ensures the homeostasis of ovarian somatic stem cells.

Current evidence has associated caspase activation with the regulation of basic cellular functions without causing apoptosis. Malfunction of non-apoptotic caspase activities may contribute to specific neurological disorders, metabolic diseases, autoimmune conditions and cancers. However, our understanding of non-apoptotic caspase functions remains limited. Here, we show that non-apoptotic caspase activation prevents the intracellular accumulation of the Patched receptor in autophagosomes and the subsequent Patched-dependent induction of autophagy in Drosophila follicular stem cells. These events ultimately sustain Hedgehog signalling and the physiological properties of ovarian somatic stem cells and their progeny under moderate thermal stress. Importantly, our key findings are partially conserved in ovarian somatic cells of human origin. These observations attribute to caspases a pro-survival role under certain cellular conditions.

The germline factor DDX4 contributes to the chemoresistance of small cell lung cancer cells.

Human cancers often re-express germline factors, yet their mechanistic role in oncogenesis and cancer progression remains unknown. Here we demonstrate that DEAD-box helicase 4 (DDX4), a germline factor and RNA helicase conserved in all multicellular organisms, contributes to increased cell motility and cisplatin-mediated drug resistance in small cell lung cancer (SCLC) cells. Proteomic analysis suggests that DDX4 expression upregulates proteins related to DNA repair and immune/inflammatory response. Consistent with these trends in cell lines, DDX4 depletion compromised in vivo tumor development while its overexpression enhanced tumor growth even after cisplatin treatment in nude mice. Further, the relatively higher DDX4 expression in SCLC patients correlates with decreased survival and shows increased expression of immune/inflammatory response markers. Taken together, we propose that DDX4 increases SCLC cell survival, by increasing the DNA damage and immune response pathways, especially under challenging conditions such as cisplatin treatment.

Non-apoptotic activation of Drosophila caspase-2/9 modulates JNK signaling, the tumor microenvironment, and growth of wound-like tumors.

Resistance to apoptosis due to caspase deregulation is considered one of the main hallmarks of cancer. However, the discovery of novel non-apoptotic caspase functions has revealed unknown intricacies about the interplay between these enzymes and tumor progression. To investigate this biological problem, we capitalized on a Drosophila tumor model with human relevance based on the simultaneous overactivation of the EGFR and the JAK/STAT signaling pathways. Our data indicate that widespread non-apoptotic activation of initiator caspases limits JNK signaling and facilitates cell fate commitment in these tumors, thus preventing the overgrowth and exacerbation of malignant features of transformed cells. Intriguingly, caspase activity also reduces the presence of macrophage-like cells with tumor-promoting properties in the tumor microenvironment. These findings assign tumor-suppressing activities to caspases independent of apoptosis, while providing molecular details to better understand the contribution of these enzymes to tumor progression.

Atezolizumab and Bevacizumab in Patients with Unresectable Hepatocellular Carcinoma: Pharmacokinetic and Safety Assessments Based on Hepatic Impairment Status and Geographic Region.

INTRODUCTION: Phase 1b GO30140 and phase 3 IMbrave150 studies evaluated first-line atezolizumab + bevacizumab for unresectable hepatocellular carcinoma (HCC). Here, we evaluated pharmacokinetics (PK) and safety by hepatic impairment status and geographic region. METHODS: Patients received atezolizumab 1,200 mg + bevacizumab 15 mg/kg IV every 3 weeks. Drug concentrations were evaluated by descriptive statistics and population PK. PK and adverse event frequencies were evaluated by hepatic impairment status and region. RESULTS: 323 IMbrave150 patients and 162 GO30140 patients were PK evaluable. Compared with IMbrave150 patients who had normal hepatic function per the National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) criteria (n = 123), patients with mild impairment (n = 171) had a geometric mean ratio (GMR) of 0.92 for cycle 1 atezolizumab area under the concentration-time curve (AUC); patients with moderate impairment (n = 27) had a GMR of 0.88. Patients in Asia ([n = 162] vs. outside [n = 161]) had a GMR of 1.25 for cycle 1 atezolizumab AUC. Compared with GO30140 patients who had normal hepatic function (NCI-ODWG [n = 61]), patients with mild impairment (n = 92) had a GMR of 0.97 for cycle 1 peak bevacizumab concentrations; those with moderate impairment (n = 9) had a GMR of 0.94. Patients in Asia (n = 111) versus outside Asia (n = 51) had a GMR of 0.94 for cycle 1 peak bevacizumab concentration. PK results were generally comparable when evaluated based on additional hepatic functional definitions (Child-Pugh or albumin/bilirubin criteria) or study enrollment in Japan. No associations between atezolizumab PK and HCC etiology were seen. Adverse event frequencies were similar across evaluated groups. CONCLUSIONS: IMbrave150 and GO30140 patients with unresectable HCC had varying baseline hepatic impairment and high enrollment from Asia. PK data demonstrated considerable exposure overlap across groups. Treatment was tolerable across groups. No need for dose adjustment based on mild or moderate hepatic impairment or region is recommended based on this analysis.

Atezolizumab plus Bevacizumab versus Sorafenib in the Chinese Subpopulation with Unresectable Hepatocellular Carcinoma: Phase 3 Randomized, Open-Label IMbrave150 Study.

INTRODUCTION: Atezolizumab plus bevacizumab significantly improved overall survival (OS) and progression-free survival (PFS) versus sorafenib in patients with unresectable hepatocellular carcinoma (HCC) in IMbrave150. Efficacy and safety data from the Chinese subpopulation are reported. METHODS: IMbrave150, a global, randomized, open-label, phase 3 study in patients with systemic treatment-naive unresectable HCC, included an extension phase that enrolled additional patients from mainland China. Patients were randomized (2:1) to receive intravenous atezolizumab 1,200 mg plus bevacizumab 15 mg/kg once every 3 weeks or sorafenib 400 mg twice a day until unacceptable toxicity or loss of clinical benefit. Co-primary endpoints were OS and independent review facility-assessed PFS per Response Evaluation Criteria in Solid Tumors version 1.1 in the intention-to-treat population. RESULTS: Of 194 Chinese patients enrolled from April 16, 2018, to April 8, 2019 (137 in the global study and 57 in the China extension phase), 133 received atezolizumab plus bevacizumab and 61 received sorafenib. At the data cutoff (August 29, 2019), the stratified hazard ratio for OS was 0.44 (95% CI, 0.25-0.76) and for PFS was 0.60 (95% CI, 0.40-0.90). The respective median OS and PFS with atezolizumab plus bevacizumab were not reached (NR; 95% CI, 13.5 months to NR) and 5.7 months (95% CI, 4.2-8.3) versus 11.4 months (95% CI, 6.7 to NR) and 3.2 months (95% CI, 2.6-4.8) with sorafenib. Grade 3-4 adverse events (AEs) occurred in 78 of 132 (59.1%) atezolizumab plus bevacizumab-treated and 27 of 58 (46.6%) sorafenib-treated patients. The most common grade 3-4 AE with atezolizumab plus bevacizumab was hypertension, occurring in 15.2% of patients; however, other high-grade AEs were infrequent. CONCLUSION: Clinically meaningful improvements in OS and PFS observed with atezolizumab plus bevacizumab versus sorafenib suggest that atezolizumab plus bevacizumab may become a practice-changing treatment for Chinese patients with unresectable HCC.

Patient-reported outcomes with atezolizumab plus bevacizumab versus sorafenib in patients with unresectable hepatocellular carcinoma (IMbrave150): an open-label, randomised, phase 3 trial.

BACKGROUND: Understanding patients' experience of cancer treatment is important. We aimed to evaluate patient-reported outcomes (PROs) with atezolizumab plus bevacizumab versus sorafenib in patients with advanced hepatocellular carcinoma in the IMbrave150 trial, which has already shown significant overall survival and progression-free survival benefits with this combination therapy. METHODS: We did an open-label, randomised, phase 3 trial in 111 hospitals and cancer centres across 17 countries or regions. We included patients aged 18 years or older with systemic, treatment-naive, histologically, cytologically, or clinically confirmed unresectable hepatocellular carcinoma and an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, with disease that was not amenable to curative surgical or locoregional therapies, or progressive disease after surgical or locoregional therapies. Participants were randomly assigned (2:1; using permuted block randomisation [blocks of six], stratified by geographical region; macrovascular invasion, extrahepatic spread, or both; baseline alpha-fetoprotein concentration; and ECOG performance status) to receive 1200 mg atezolizumab plus 15 mg/kg bevacizumab intravenously once every 3 weeks or 400 mg sorafenib orally twice a day, until loss of clinical benefit or unacceptable toxicity. The independent review facility for tumour assessment was masked to the treatment allocation. Previously reported coprimary endpoints were overall survival and independently assessed progression-free survival per Response Evaluation Criteria in Solid Tumors 1.1. Prespecified secondary and exploratory analyses descriptively evaluated treatment effects on patient-reported quality of life, functioning, and disease symptoms per the European Organisation for Research and Treatment of Cancer (EORTC) quality-of-life questionnaire for cancer (QLQ-C30) and quality-of-life questionnaire for hepatocellular carcinoma (QLQ-HCC18). Time to confirmed deterioration of PROs was analysed in the intention-to-treat population; all other analyses were done in the PRO-evaluable population (patients who had a baseline PRO assessment and at least one assessment after baseline). The trial is ongoing; enrolment is closed. This trial is registered with ClinicalTrials.gov, NCT03434379. FINDINGS: Between March 15, 2018, and Jan 30, 2019, 725 patients were screened and 501 patients were enrolled and randomly assigned to atezolizumab plus bevacizumab (n=336) or sorafenib (n=165). 309 patients in the atezolizumab plus bevacizumab group and 145 patients in the sorafenib group were included in the PRO-evaluable population. At data cutoff (Aug 29, 2019) the median follow-up was 8·6 months (IQR 6·2-10·8). EORTC QLQ-C30 completion rates were 90% or greater for 23 of 24 treatment cycles in both groups (range 88-100% in the atezolizumab plus bevacizumab group and 80-100% in the sorafenib group). EORTC QLQ-HCC18 completion rates were 90% or greater for 20 of 24 cycles in the atezolizumab plus bevacizumab group (range 88-100%) and 21 of 24 cycles in the sorafenib group (range 89-100%). Compared with sorafenib, atezolizumab plus bevacizumab reduced the risk of deterioration on all EORTC QLQ-C30 generic cancer symptom scales that were prespecified for analysis (appetite loss [hazard ratio (HR) 0·57, 95% CI 0·40-0·81], diarrhoea [0·23, 0·16-0·34], fatigue [0·61, 0·46-0·81], pain [0·46, 0·34-0·62]), and two of three EORTC QLQ-HCC18 disease-specific symptom scales that were prespecified for analysis (fatigue [0·60, 0·45-0·80] and pain [0·65, 0·46-0·92], but not jaundice [0·76, 0·55-1·07]). At day 1 of treatment cycle five (after which attrition in the sorafenib group was more than 50%), the mean EORTC QLQ-C30 score changes from baseline in the atezolizumab plus bevacizumab versus sorafenib groups were: -3·29 (SD 17·56) versus -5·83 (20·63) for quality of life, -4·02 (19·42) versus -9·76 (21·33) for role functioning, and -3·77 (12·82) versus -7·60 (15·54) for physical functioning. INTERPRETATION: Prespecified analyses of PRO data showed clinically meaningful benefits in terms of patient-reported quality of life, functioning, and disease symptoms with atezolizumab plus bevacizumab compared with sorafenib, strengthening the combination therapy's positive benefit-risk profile versus that of sorafenib in patients with unresectable hepatocellular carcinoma. FUNDING: F Hoffmann-La Roche and Genentech.

Functional contribution of DCLKs in sea urchin development.

BACKGROUND: Doublecortin-like kinase1 and 2 (DCLKs) are protein Ser/Thr kinases important for neuronal development. More recently, they are also reported to regulate plasticity such as cell proliferation and differentiation of stem cells and cancer cells, but the details of their functions in this biological context are still unclear. With an attempt to reveal the functions of DCLKs in plasticity regulation, we here used the sea urchin embryo that undergoes highly regulative development as an experimental model. RESULTS: We found that both the transcripts and the proteins of DCLKs are uniformly present during early embryogenesis and with some enrichment in mesenchymal cells after gastrula stage. Knockdown of DCLKs induced general developmental delay and defects at day 2. Further, the damage on the embryo/larva induced ectopic expression of DCLKs in the ectoderm where the damage was most severe. Under a tumor-prone or -suppressive condition, DCLKs expression was upregulated or downregulated, respectively, after damage. In both cases, the embryos showed severe developmental defects. CONCLUSIONS: Taken together, a transient upregulation of DCLKs appears to be involved in a damage response both during normal and abnormal development, and which could result in different phenotypes in a context dependent manner.

The ELAV/Hu protein Found in neurons regulates cytoskeletal and ECM adhesion inputs for space-filling dendrite growth.

Dendritic arbor morphology influences how neurons receive and integrate extracellular signals. We show that the ELAV/Hu family RNA-binding protein Found in neurons (Fne) is required for space-filling dendrite growth to generate highly branched arbors of Drosophila larval class IV dendritic arborization neurons. Dendrites of fne mutant neurons are shorter and more dynamic than in wild-type, leading to decreased arbor coverage. These defects result from both a decrease in stable microtubules and loss of dendrite-substrate interactions within the arbor. Identification of transcripts encoding cytoskeletal regulators and cell-cell and cell-ECM interacting proteins as Fne targets using TRIBE further supports these results. Analysis of one target, encoding the cell adhesion protein Basigin, indicates that the cytoskeletal defects contributing to branch instability in fne mutant neurons are due in part to decreased Basigin expression. The ability of Fne to coordinately regulate the cytoskeleton and dendrite-substrate interactions in neurons may shed light on the behavior of cancer cells ectopically expressing ELAV/Hu proteins.

Atezolizumab plus Bevacizumab in Unresectable Hepatocellular Carcinoma.

BACKGROUND: The combination of atezolizumab and bevacizumab showed encouraging antitumor activity and safety in a phase 1b trial involving patients with unresectable hepatocellular carcinoma. METHODS: In a global, open-label, phase 3 trial, patients with unresectable hepatocellular carcinoma who had not previously received systemic treatment were randomly assigned in a 2:1 ratio to receive either atezolizumab plus bevacizumab or sorafenib until unacceptable toxic effects occurred or there was a loss of clinical benefit. The coprimary end points were overall survival and progression-free survival in the intention-to-treat population, as assessed at an independent review facility according to Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1). RESULTS: The intention-to-treat population included 336 patients in the atezolizumab-bevacizumab group and 165 patients in the sorafenib group. At the time of the primary analysis (August 29, 2019), the hazard ratio for death with atezolizumab-bevacizumab as compared with sorafenib was 0.58 (95% confidence interval [CI], 0.42 to 0.79; P<0.001). Overall survival at 12 months was 67.2% (95% CI, 61.3 to 73.1) with atezolizumab-bevacizumab and 54.6% (95% CI, 45.2 to 64.0) with sorafenib. Median progression-free survival was 6.8 months (95% CI, 5.7 to 8.3) and 4.3 months (95% CI, 4.0 to 5.6) in the respective groups (hazard ratio for disease progression or death, 0.59; 95% CI, 0.47 to 0.76; P<0.001). Grade 3 or 4 adverse events occurred in 56.5% of 329 patients who received at least one dose of atezolizumab-bevacizumab and in 55.1% of 156 patients who received at least one dose of sorafenib. Grade 3 or 4 hypertension occurred in 15.2% of patients in the atezolizumab-bevacizumab group; however, other high-grade toxic effects were infrequent. CONCLUSIONS: In patients with unresectable hepatocellular carcinoma, atezolizumab combined with bevacizumab resulted in better overall and progression-free survival outcomes than sorafenib. (Funded by F. Hoffmann-La Roche/Genentech; ClinicalTrials.gov number, NCT03434379.).

A tumor suppressor Retinoblastoma1 is essential for embryonic development in the sea urchin.

BACKGROUND: Embryonic cells and cancer cells share various cellular characteristics important for their functions. It has been thus proposed that similar mechanisms of regulation may be present in these otherwise disparate cell types. RESULTS: To explore how regulative embryonic cells are fundamentally different from cancerous cells, we report here that a fine balance of a tumor suppressor protein Retinoblastoma1 (Rb1) and a germline factor Vasa are important for proper cell proliferation and differentiation of the somatic cells during embryogenesis of the sea urchin. Rb1 knockdown blocked embryonic development and induced Vasa accumulation in the entire embryo, while its overexpression resulted in a smaller-sized embryo with differentiated body structures. These results suggest that a titrated level of Rb1 protein may be essential for a proper balance of cell proliferation and differentiation during development. Vasa knockdown or overexpression, on the other hand, reduced or increased Rb1 protein expression, respectively. CONCLUSIONS: Taken together, it appears that Vasa protein positively regulates Rb1 protein while Rb1 protein negatively regulates Vasa protein, balancing the act of these two antagonistic molecules in somatic cells. This mechanism may provide a fine control of cell proliferation and differentiation, which is essential for regulative embryonic development.

Learning on the Fly: The Interplay between Caspases and Cancer.

The ease of genetic manipulation, as well as the evolutionary conservation of gene function, has placed Drosophila melanogaster as one of the leading model organisms used to understand the implication of many proteins with disease development, including caspases and their relation to cancer. The family of proteases referred to as caspases have been studied over the years as the major regulators of apoptosis: the most common cellular mechanism involved in eliminating unwanted or defective cells, such as cancerous cells. Indeed, the evasion of the apoptotic programme resulting from caspase downregulation is considered one of the hallmarks of cancer. Recent investigations have also shown an instrumental role for caspases in non-lethal biological processes, such as cell proliferation, cell differentiation, intercellular communication, and cell migration. Importantly, malfunction of these essential biological tasks can deeply impact the initiation and progression of cancer. Here, we provide an extensive review of the literature surrounding caspase biology and its interplay with many aspects of cancer, emphasising some of the key findings obtained from Drosophila studies. We also briefly describe the therapeutic potential of caspase modulation in relation to cancer, highlighting shortcomings and hopeful promises.

Non-apoptotic Caspase regulation of stem cell properties.

The evolutionarily conserved family of proteins called caspases are the main factors mediating the orchestrated programme of cell suicide known as apoptosis. Since this protein family was associated with this essential biological function, the majority of scientific efforts were focused towards understanding their molecular activation and function during cell death. However, an emerging body of evidence has highlighted a repertoire of non-lethal roles within a large variety of cell types, including stem cells. Here we intend to provide a comprehensive overview of the key role of caspases as regulators of stem cell properties. Finally, we briefly discuss the possible pathological consequences of caspase malfunction in stem cells, and the therapeutic potential of caspase regulation applied to this context.

Isorhapontigenin suppresses growth of patient-derived glioblastoma spheres through regulating miR-145/SOX2/cyclin D1 axis.

BACKGROUND: Glioblastoma (GBM) is the most common malignant brain tumor, and glioma stem cells (GSCs) are considered a major source of treatment resistance for glioblastoma. Identifying new compounds that inhibit the growth of GSCs and understanding their underlying molecular mechanisms are therefore important for developing novel therapy for GBM. METHODS: We investigated the potential inhibitory effect of isorhapontigenin (ISO), an anticancer compound identified in our recent investigations, on anchorage-independent growth of patient-derived glioblastoma spheres (PDGS) and its mechanism of action. RESULTS: ISO treatment resulted in significant anchorage-independent growth inhibition, accompanied with cell cycle G0-G1 arrest and cyclin D1 protein downregulation in PDGS. Further studies established that cyclin D1 was downregulated by ISO at transcription levels in a SOX2-dependent manner. In addition, ISO attenuated SOX2 expression by specific induction of miR-145, which in turn suppressed 3'UTR activity of SOX2 mRNA without affecting its mRNA stability. Moreover, ectopic expression of exogenous SOX2 rendered D456 cells resistant to induction of cell cycle G0-G1 arrest and anchorage-independent growth inhibition upon ISO treatment, whereas inhibition of miR-145 resulted in D456 cells resistant to ISO inhibition of SOX2 and cyclin D1 expression. In addition, overexpression of miR-145 mimicked ISO treatment in D456 cells. CONCLUSIONS: ISO induces miR-145 expression, which binds to the SOX2 mRNA 3'UTR region and inhibits SOX2 protein translation. Inhibition of SOX2 leads to cyclin D1 downregulation and PDGS anchorage-independent growth inhibition. The elucidation of the miR-145/SOX2/cyclin D1 axis in PDGS provides a significant insight into understanding the anti-GBM effect of ISO compound.

NF-κB1 inhibits c-Myc protein degradation through suppression of FBW7 expression.

NF-κB is a well-known transcription factor in regulation of multiple gene transcription and biological processes, and most of them are relied on its transcriptional activity of the p65/RelA subunit, while biological function of another ubiquitously expressed subunit NF-κB1 (p50) remains largely unknown due to lack transcriptional activation domain. Here we discovered a novel biological function of p50 as a regulator of oncogenic c-Myc protein degradation upon arsenite treatment in a NF-κB transcriptional-independent mechanism. Our results found that p50 was crucial for c-Myc protein induction following arsenite treatment by using specific knockdown and deletion of p50 in its normal expressed cells as well as reconstituting expression of p50 in its deficient cells. Subsequently we showed that p50 upregulated c-Myc protein expression mainly through inhibiting its degradation. We also identified that p50 exhibited this novel property by suppression of FBW7 expression. FBW7 was profoundly upregulated in p50-deficient cells in comparison to that in p50 intact cells, whereas knockdown of FBW7 in p50-/- cells restored arsenite-induced c-Myc protein accumulation, assuring that FBW7 up-regulation was responsible for defect of c-Myc protein expression in p50-/- cells. In addition, we discovered that p50 suppressed fbw7 gene transcription via inhibiting transcription factor E2F1 transactivation. Collectively, our studies demonstrated a novel function of p50 as a regulator of c-Myc protein degradation, contributing to our notion that p50-regulated protein expression through multiple levels at protein translation and degradation, further providing a significant insight into the understanding of biomedical significance of p50 protein.

Death receptor 6 induces apoptosis not through type I or type II pathways, but via a unique mitochondria-dependent pathway by interacting with Bax protein.

Cells undergo apoptosis through two major pathways, the extrinsic pathway (death receptor pathway) and the intrinsic pathway (the mitochondrial pathway). These two pathways can be linked by caspase-8-activated truncated Bid formation. Very recently, death receptor 6 (DR6) was shown to be involved in the neurodegeneration observed in Alzheimer disease. DR6, also known as TNFRSF21, is a relatively new member of the death receptor family, and it was found that DR6 induces apoptosis when it is overexpressed. However, how the death signal mediated by DR6 is transduced intracellularly is not known. To this end, we have examined the roles of caspases, apoptogenic mitochondrial factor cytochrome c, and the Bcl-2 family proteins in DR6-induced apoptosis. Our data demonstrated that Bax translocation is absolutely required for DR6-induced apoptosis. On the other hand, inhibition of caspase-8 and knockdown of Bid have no effect on DR6-induced apoptosis. Our results strongly suggest that DR6-induced apoptosis occurs through a new pathway that is different from the type I and type II pathways through interacting with Bax.