scholarly journals Structural basis of HLX10 PD-1 receptor recognition, a promising anti-PD-1 antibody clinical candidate for cancer immunotherapy

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0257972
Author(s):  
Hassan Issafras ◽  
Shilong Fan ◽  
Chi-Ling Tseng ◽  
Yunchih Cheng ◽  
Peihua Lin ◽  
...  
Keyword(s):  
Cancer Immunotherapy ◽  
Progression Free Survival ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Functional Activities ◽  
Human T Cells ◽  
Cancer Immunotherapies ◽  
Anti Tumor Activity

Cancer immunotherapies, such as checkpoint blockade of programmed cell death protein-1 (PD-1), represents a breakthrough in cancer treatment, resulting in unprecedented results in terms of overall and progression-free survival. Discovery and development of novel anti PD-1 inhibitors remains a field of intense investigation, where novel monoclonal antibodies (mAbs) and novel antibody formats (e.g., novel isotype, bispecific mAb and low-molecular-weight compounds) are major source of future therapeutic candidates. HLX10, a fully humanized IgG4 monoclonal antibody against PD-1 receptor, increased functional activities of human T-cells and showed in vitro, and anti-tumor activity in several tumor models. The combined inhibition of PD-1/PDL-1 and angiogenesis pathways using anti-VEGF antibody may enhance a sustained suppression of cancer-related angiogenesis and tumor elimination. To elucidate HLX10’s mode of action, we solved the structure of HLX10 in complex with PD-1 receptor. Detailed epitope analysis showed that HLX10 has a unique mode of recognition compared to the clinically approved PD1 antibodies Pembrolizumab and Nivolumab. Notably, HLX10’s epitope was closer to Pembrolizumab’s epitope than Nivolumab’s epitope. However, HLX10 and Pembrolizumab showed an opposite heavy chain (HC) and light chain (LC) usage, which recognizes several overlapping amino acid residues on PD-1. We compared HLX10 to Nivolumab and Pembrolizumab and it showed similar or better bioactivity in vitro and in vivo, providing a rationale for clinical evaluation in cancer immunotherapy.

Structural basis of cofactor-mediated stabilization and substrate recognition of the α-tubulin acetyltransferase αTAT1

2015 ◽  
Vol 467 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Satoru Yuzawa ◽  
Sachiko Kamakura ◽  
Junya Hayase ◽  
Hideki Sumimoto
Keyword(s):  
Catalytic Domain ◽  
Substrate Recognition ◽  
Structural Basis ◽  
Stable Complex ◽  
Amino Acid Residues ◽  
Substrate Selection ◽  
Post Translational Modification ◽  
Acetyl Group

The functions of microtubules are controlled in part by tubulin post-translational modification including acetylation of Lys40 in α-tubulin. αTAT1 (α-tubulin acetyltransferase 1), an enzyme evolutionarily conserved among eukaryotes, has recently been identified as the major α-tubulin Lys40 acetyltransferase, in which AcCoA (acetyl-CoA) serves as an acetyl group donor. The regulation and substrate recognition of this enzyme, however, have not been fully understood. In the present study, we show that AcCoA and CoA each form a stable complex with human αTAT1 to maintain the protein integrity both in vivo and in vitro. The invariant residues Arg132 and Ser160 in αTAT1 participate in the stable interaction not only with AcCoA but also with CoA, which is supported by analysis of the present crystal structures of the αTAT1 catalytic domain in complex with CoA. Alanine substitution for Arg132 or Ser160 leads to a drastic misfolding of the isolated αTAT1 catalytic domain in the absence of CoA and AcCoA but not in the presence of excess amounts of either cofactor. A mutant αTAT1 carrying the R132A or S160A substitution is degraded much faster than the wild-type protein when expressed in mammalian Madin–Darby canine kidney cells. Furthermore, alanine-scanning experiments using Lys40-containing peptides reveal that α-tubulin Ser38 is crucial for substrate recognition of αTAT1, whereas Asp39, Ile42, the glycine stretch (amino acid residues 43–45) and Asp46 are also involved. The requirement for substrate selection is totally different from that in various histone acetyltransferases, which appears to be consistent with the inability of αTAT1 to acetylate histones.

Phase Ib study of cancer stem cell (CSC) pathway inhibitor BBI-608 administered in combination with FOLFIRI with and without bevacizumab (Bev) in patients (pts) with advanced colorectal cancer (CRC).

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 569-569 ◽  
Author(s):  
Joleen Marie Hubbard ◽  
Bert H. O'Neil ◽  
Derek J. Jonker ◽  
Thorvardur Ragnar Halfdanarson ◽  
Alexander Starodub ◽  
...  
Keyword(s):  
Adverse Events ◽  
Tumor Regression ◽  
Progression Free Survival ◽  
Open Label ◽  
Cancer Stemness ◽  
Phase Ib ◽  
Heavily Pretreated ◽  
Anti Tumor Activity

569 Background: BBI-608 is an oral first-in-class cancer stemness inhibitor that blocks STAT3-mediated transcription of cancer stemness genes. Potent anti-CSC activity was observed in vitro and in vivo,in mono and combination therapy. In phase I studies, BBI-608 was generally well tolerated with encouraging signs of anti-tumor activity. Methods: A phase Ib open label, multi-center study in pts with advanced CRC was undertaken to confirm the RP2D of BBI-608 in combination with FOLFIRI with or without BEV. BBI-608 was administered at 240 mg BID in combination with FOLFIRI (5-FU 400 mg/m2 bolus with 2400 mg/m2, irinotecan 180 mg/m2, and leucovorin 400 mg/m2infusion) with or without BEV 5 mg/kg, administered bi-weekly until progression of disease, unacceptable toxicity, or other discontinuation criterion was met. Results: 18 heavily pretreated pts with an average of > 3 prior lines of therapy of which 10 pts (56%) previously progressed on FOLFIRI were enrolled. Of the 17 pts evaluable for response, 8 pts received FOLFIRI and 9 pts received FOLFIRI with BEV in combination with BBI-608. Most common adverse events included grade 1 and 2 diarrhea, abdominal pain, nausea, vomiting and anorexia. No dose limiting toxicity or new adverse events were seen, and the safety profile was similar to that of each regimen as monotherapy. Grade 3 events related to protocol therapy included diarrhea occurring in 3 pts, fatigue in 2 pts and dehydration in 1 pt. All events resolved after dose reduction and/or start of anti-diarrheal medications. No significant pharmacokinetic interactions were observed. Disease control (PR+SD) was observed in 16 of 17 evaluable pts (94%) with 2 PR (per RECIST 1.1 criteria: 44% and 33% regression) and 14 SD (of which 13 (93%) had tumor regression < 25%). In the evaluable pts, median progression free survival was 5.54 months. Of 17 pts, 7 (41%) had prolonged SD of > 6 months. Conclusions: This phase Ib study confirmed that BBI-608 at 240 mg bid can be safely combined with FOLFIRI with and without BEV, and shows encouraging anti-tumor activity in heavily pretreated CRC pts, even in pts with prior progression on FOLFIRI-based therapy. Clinical trial information: NCT02024607.

Phase 2 study of pembrolizumab in combination with azacitidine in subjects with metastatic colorectal cancer.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3054-3054 ◽  
Author(s):  
James J. Lee ◽  
Weijing Sun ◽  
Nathan Bahary ◽  
James Ohr ◽  
John C. Rhee ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Metastatic Colorectal Cancer ◽  
Tumor Progression ◽  
Progression Free Survival ◽  
Phase 2 ◽  
Anti Tumor Activity ◽  
Study Therapy

3054 Background: Microsatellite stable (MSS) metastatic colorectal cancer (mCRC) has relatively poor tumoral infiltration of CD8+ T cells and is resistant to pembrolizumab (Pembro) when compared to MSI-H mCRC. DNA hypomethylating agent induces epigenetic expression of multiple genes including cancer-testis antigens in CRC, which are recognized by cytotoxic CD8+ T cells in vitro and in vivo. This trial tested whether concurrent treatment with azacitidine (Aza) could enhance the anti-tumor activity of Pembro. Methods: This is a phase 2 trial to evaluate anti-tumor activity and safety of Pembro plus Aza in patients (pts) with previously treated mCRC without any further standard chemotherapy option. Pts received Pembro 200 mg IV on day 1 of each cycle Q3W and Aza 100 mg daily SQ injection on days 1-5 of each cycle Q3W. Primary endpoint was response rate (ORR) using RECIST v1.1. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). Tumor tissues were collected for correlative studies. Results: Thirty-one pts were enrolled [median age, 61 years (range, 30-79); 17 M/14 F; ECOG PS 0/1 (58%/42%); 30 pts with MSS mCRC]. Pts received at least 2 lines of prior systemic chemotherapy for mCRC (median, 3; range, 1-5). Thirty pts received at least one dose of study therapy (median, 3 cycles; range, 1-8). Ten pts could not complete the first 3 cycles due to rapid symptomatic tumor progression. One pt with MSS mCRC achieved PR and 3 pts had SD as best response. The ORR was 3% (1/30; 95% CI, 0.1-17%). Seven pts with PD at the end of cycle 3 continued on study therapy, and 2 pts had stabilization of tumor progression. Median PFS was 2.1 months (95% CI, 1.8-2.8), and median OS was 6.2 months (95% CI, 3.5-8.7). While treatment-related adverse events (TRAEs) were reported in 63% of pts, most of the TRAEs were Gr 1/2 (96%). Frequent TRAEs possibly related to Aza were anemia (n = 5), constipation (n = 5), and leukopenia (n = 4); and possibly related to both Aza and Pembro were nausea (n = 5) and fatigue (n = 5). Gr 3 TRAEs included anemia (n = 1), ALT elevation (n = 1), and alkaline phosphatase elevation (n = 1). Conclusions: Pembro plus Aza is feasible with a tolerable safety profile but appears to have minimal anti-tumor effect for MSS mCRC. Clinical trial information: NCT02260440.

scholarly journals Structural Basis of Stu2 Recruitment to Yeast Kinetochores

2020 ◽  
Author(s):  
Jacob A. Zahm ◽  
Michael G. Stewart ◽  
Joseph S. Carrier ◽  
Stephen C. Harrison ◽  
Matthew P. Miller
Keyword(s):  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Terminal Segment ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Checkpoint Signaling ◽  
Delay Cell ◽  
Sister Chromatids

ABSTRACTAccurate chromosome segregation during cell division requires engagement of the kinetochores of sister chromatids with microtubules emanating from opposite poles of the mitotic spindle. In yeast, these “bioriented” metaphase sister chromatids experience tension as the corresponding microtubules (one per sister chromatid) shorten. Spindle-assembly checkpoint signaling appears to cease from a kinetochore under tension, which also stabilizes kinetochore-microtubule attachment in single-kinetochore experiments in vitro. The microtubule polymerase, Stu2, the yeast member of the XMAP215/ch-TOG protein family, associates with kinetochores in cells and contributes to tension-dependent stabilization, both in vitro and in vivo. We show here that a C-terminal segment of Stu2 binds the four-way junction of the Ndc80 complex (Ndc80c) and that amino-acid residues conserved both in yeast Stu2 orthologs and in their metazoan counterparts make specific contacts with Ndc80 and Spc24. Mutations that perturb this interaction prevent association of Stu2 with kinetochores, impair cell viability, produce biorientation defects, and delay cell-cycle progression. Ectopic tethering of the mutant Stu2 species to the Ndc80c junction restores wild-type function. These findings show that the role of Stu2 in tension sensing depends on its association with kinetochores by binding with Ndc80c.

scholarly journals Leveraging Patient‐Derived Models for Immunotherapy Research

2020 ◽  
pp. e344-e350
Author(s):  
Katerina Politi
Keyword(s):  
Cancer Immunotherapy ◽  
Cancer Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Experimental Models ◽  
Cancer Types ◽  
Cancer Immunotherapies ◽  
Immune Oncology

As cancer immunotherapies become mainstream for the treatment of many different cancer types and the numbers of new agents continue to increase, the need for experimental models is also rising. An approach to develop and study models for immune-oncology that has garnered intense interest in recent years is that of using patient-derived models. Patient-derived models can recapitulate many of the features and heterogeneity of the corresponding human tumors. Historically these models have been used to study cancer cell–intrinsic properties of tumors and drugs that target tumor cells directly. In recent years, increasing recognition of the role immune cells play in cancer and how these represent good therapeutic targets has led to efforts to optimize and use patient-derived models for cancer immunotherapy studies. Patient-derived models are now being used to study the properties of cancer cells that modulate their ability to respond to immune stimulation. Further efforts are underway to use and develop patient-derived models that incorporate human immune cells in vitro and in vivo (humanized mice) so that cancer cell–immune cell interactions can be studied in the context of cancer immunotherapies. As these models are further refined, leveraging patient-derived models for cancer immunotherapy research can provide insight into mechanisms of sensitivity and resistance to cancer immunotherapies, uncover new targets, reveal how specific agents work, and be used to evaluate the antitumor efficacy of therapeutic regimens.

A phase Ib study of cancer stem cell (CSC) pathway inhibitor BBI-608 in combination with gemcitabine and nab-paclitaxel (nab-PTX) in patients (pts) with metastatic pancreatic ductal adenocarcinoma (mPDAC).

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 284-284 ◽  
Author(s):  
Safi Shahda ◽  
Bassel F. El-Rayes ◽  
Bert H. O'Neil ◽  
Alexander Starodub ◽  
Wahid Tewfik Hanna ◽  
...  
Keyword(s):  
Tumor Regression ◽  
Progression Free Survival ◽  
Ductal Adenocarcinoma ◽  
Open Label ◽  
Cancer Stemness ◽  
Durable Response ◽  
Phase Ib ◽  
Anti Tumor Activity

284 Background: BBI-608 is an oral first-in-class cancer stemness inhibitor that works by blocking STAT3-mediated transcription of cancer stemness genes. Potent anti-CSC activity was observed in vitro and in vivo, in mono- and combination therapy. In phase I studies, BBI-608 was generally well tolerated with encouraging signs of anti-tumor activity. Methods: A phase Ib open label, multi-center study in pts with mPDAC was performed to determine RP2D, safety, tolerability, and preliminary anti-cancer activity of BBI-608 in combination with Gemcitabine and nab-PTX. BBI-608 was administered at 240 mg BID in combination with Gemcitabine 125 mg/m2 and nab-PTX 1000 mg/m2administered weekly for 3 out every 4 weeks until progression of disease, unacceptable toxicity, or other discontinuation criterion was met. Results: 31 pts were enrolled and received BBI-608 in combination with Gemcitabine and nab-PTX for a total sum of 83 study cycles. 25 of 31 pts (80.6%) were treatment-naïve and 6 pts (19.4%) received 1 prior line of systemic therapy. Most common adverse events included grade 1 diarrhea, abdominal pain, nausea, and fatigue. Combination treatment was well tolerated with no dose-limiting toxicity observed and safety profile similar to that of each agent individually. One patient experienced grade 3 event of dehydration related to protocol therapy which resolved with hydration. Of the 8 pts enrolled in the RP2D determination portion of the study, 7 pts were evaluable for response with disease control (PR + SD) was observed in 7/7 pts (100%). Tumor regression was observed in 6/7 (85.7%) with 3 PR (41.3%, 37.6% and 33.3% regression) and 3 SD (25.8%, 21.1%, and 19.9% regression). The median progression free survival was 7.8 months with PR or SD of > 6 months in 6/8 pts (75%). Conclusions: This phase Ib study demonstrated that BBI-608 at 240 mg BID can be safely combined with Gemcitabine and nab-PTX. Encouraging anti-tumor activity with durable response was observed in pts with mPDAC. Clinical trial information: NCT02231723.

Derivatives of Deoxypodophyllotoxin Induce Apoptosis Through Bcl-2/Bax Proteins Expression

2020 ◽  
Vol 20 ◽  
Author(s):  
Ya-Nan Li ◽  
Ni Ning ◽  
Lei Song ◽  
Yun Geng ◽  
Jun-Ting Fan ◽  
...  
Keyword(s):  
Annexin V ◽  
Mtt Method ◽  
Anthriscus Sylvestris ◽  
Anti Tumor Activity ◽  
Derivatives Of ◽  
Toxicity In Vitro ◽  
Ht 29 ◽  
Mcf 7

Background: Deoxypodophyllotoxin, isolated from theTraditional Chinese Medicine Anthriscus sylvestris, is well-known because of its significant antitumor activity with strong toxicity in vitro and in vivo. Objective: In this article, we synthesized a series of deoxypodophyllotoxin derivatives, and evaluated their antitumor effectiveness.Methods:The anti tumor activity of deoxypodophyllotoxin derivatives was investigated by the MTT method. Apoptosis percentage was measured by flow cytometer analysis using Annexin-V-FITC. Results: The derivatives revealed obvious cytotoxicity in the MTT assay by decreasing the number of late cancer cells. The decrease of Bcl-2/Bax could be observed in MCF-7, HepG2, HT-29 andMG-63 using Annexin V-FITC. The ratio of Bcl-2/Bax in the administration group was decreased, which was determined by the ELISA kit. Conclusion: The derivatives of deoxypodophyllotoxin could induce apoptosis in tumor cell lines by influencing Bcl-2/Bax.

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
The Other ◽  
Amino Acid Residues ◽  
Phase Synthesis ◽  
Other Hand ◽  
Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

Synthesis of Fragments of the Vasoactive Intestinal Peptide (VIP) and Analysis of Their Residual Biological Activities

1995 ◽  
Vol 60 (7) ◽  
pp. 1229-1235 ◽  
Author(s):  
Ivana Zoulíková ◽  
Ivan Svoboda ◽  
Jiří Velek ◽  
Václav Kašička ◽  
Jiřina Slaninová ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Residual Activity ◽  
Detailed Examination ◽  
Amino Acid Residues ◽  
Linear Peptide ◽  
Zone Electrophoresis ◽  
Capillary Zone

The vasoactive intestinal (poly)peptide (VIP) is a linear peptide containing 28 amino acid residues, whose primary structure indicates a low metabolic stability. The following VIP fragments, as potential metabolites, and their analogues were prepared by synthesis on a solid: [His(Dnp)1]VIP(1-10), VIP(11-14), [D-Arg12]VIP(11-14), [Lys(Pac)15,21,Arg20]VIP(15-22), and VIP(23-28). After purification, the peptides were characterized by amino acid analysis, mass spectrometry, RP HPLC, and capillary zone electrophoresis. In some tests, detailed examination of the biological activity of the substances in vivo and in vitro gave evidence of a low, residual activity of some fragments, viz. a depressoric activity in vivo for [His(Dnp)1]VIP(1-10) and a stimulating activity for the release of α-amylase in vitro and in vivo for [Lys(Pac)15,21,Arg20]VIP(15-22) and VIP(23-28).

scholarly journals The impact of FGF19/FGFR4 signaling inhibition in antitumor activity of multi-kinase inhibitors in hepatocellular carcinoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroaki Kanzaki ◽  
Tetsuhiro Chiba ◽  
Junjie Ao ◽  
Keisuke Koroki ◽  
Kengo Kanayama ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Progression Free Survival ◽  
Erk Signaling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antitumor Effects ◽  
The Impact

AbstractFGF19/FGFR4 autocrine signaling is one of the main targets for multi-kinase inhibitors (MKIs). However, the molecular mechanisms underlying FGF19/FGFR4 signaling in the antitumor effects to MKIs in hepatocellular carcinoma (HCC) remain unclear. In this study, the impact of FGFR4/ERK signaling inhibition on HCC following MKI treatment was analyzed in vitro and in vivo assays. Serum FGF19 in HCC patients treated using MKIs, such as sorafenib (n = 173) and lenvatinib (n = 40), was measured by enzyme-linked immunosorbent assay. Lenvatinib strongly inhibited the phosphorylation of FRS2 and ERK, the downstream signaling molecules of FGFR4, compared with sorafenib and regorafenib. Additional use of a selective FGFR4 inhibitor with sorafenib further suppressed FGFR4/ERK signaling and synergistically inhibited HCC cell growth in culture and xenograft subcutaneous tumors. Although serum FGF19high (n = 68) patients treated using sorafenib exhibited a significantly shorter progression-free survival and overall survival than FGF19low (n = 105) patients, there were no significant differences between FGF19high (n = 21) and FGF19low (n = 19) patients treated using lenvatinib. In conclusion, robust inhibition of FGF19/FGFR4 is of importance for the exertion of antitumor effects of MKIs. Serum FGF19 levels may function as a predictive marker for drug response and survival in HCC patients treated using sorafenib.

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