Irreversible binding of an anticancer compound (BI-94) to plasma proteins

Nagsen Gautam, Rhishikesh Thakare, Sandeep Rana, Amarnath Natarajan, Yazen Alnouti

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

1. We investigated the mechanisms responsible for the in vivo instability of a benzofurazan compound BI-94 (NSC228148) with potent anti-cancer activity.2. BI-94 was stable in MeOH, water, and in various buffers at pHs 2.5-5, regardless of the buffer composition. In contrast, BI-94 was unstable in NaOH and at pHs 7-9, regardless of the buffer composition. BI-94 disappeared immediately after spiking into mice, rat, monkey, and human plasma. BI-94 stability in plasma can be only partially restored by acidifying it, which indicated other mechanisms in addition to pH for BI-94 instability in plasma.3. BI-94 formed adducts with the trapping agents, glutathione (GSH) and N-acetylcysteine (NAC), in vivo and in vitro via nucleophilic aromatic substitution reaction. The kinetics of adduct formation showed that neutral or physiological pHs enhanced and accelerated GSH and NAC adduct formation with BI-94, whereas acidic pHs prevented it. Therefore, physiological pHs not only altered BI-94 chemical stability but also enhanced adduct formation with endogenous nucleophiles. In addition, adduct formation with human serum albumin-peptide 3 (HSA-T3) at the Cys34 position was demonstrated.4. In conclusion, BI-94 was unstable at physiological conditions due to chemical instability and irreversible binding to plasma proteins.

Original languageEnglish (US)
Pages (from-to)858-873
Number of pages16
JournalXenobiotica
Volume45
Issue number10
DOIs
StatePublished - Oct 3 2015

Fingerprint

Blood Proteins
Buffers
Acetylcysteine
Plasma (human)
Serum Albumin
Nucleophiles
Haplorhini
Glutathione
Chemical stability
Chemical analysis
Rats
Peptides
Substitution reactions
Water
Plasmas
Kinetics
NSC228148
Neoplasms
In Vitro Techniques
benzofurazan

Keywords

  • Glutathione
  • LC-MS/MS
  • N-acetylcysteine
  • irreversible protein binding
  • isotopic filtering

ASJC Scopus subject areas

  • Biochemistry
  • Toxicology
  • Pharmacology
  • Health, Toxicology and Mutagenesis

Cite this

Irreversible binding of an anticancer compound (BI-94) to plasma proteins. / Gautam, Nagsen; Thakare, Rhishikesh; Rana, Sandeep; Natarajan, Amarnath; Alnouti, Yazen.

In: Xenobiotica, Vol. 45, No. 10, 03.10.2015, p. 858-873.

Research output: Contribution to journalArticle

Gautam, Nagsen ; Thakare, Rhishikesh ; Rana, Sandeep ; Natarajan, Amarnath ; Alnouti, Yazen. / Irreversible binding of an anticancer compound (BI-94) to plasma proteins. In: Xenobiotica. 2015 ; Vol. 45, No. 10. pp. 858-873.
@article{0b1ee98a36e04ffdadcf1848bd58798d,
title = "Irreversible binding of an anticancer compound (BI-94) to plasma proteins",
abstract = "1. We investigated the mechanisms responsible for the in vivo instability of a benzofurazan compound BI-94 (NSC228148) with potent anti-cancer activity.2. BI-94 was stable in MeOH, water, and in various buffers at pHs 2.5-5, regardless of the buffer composition. In contrast, BI-94 was unstable in NaOH and at pHs 7-9, regardless of the buffer composition. BI-94 disappeared immediately after spiking into mice, rat, monkey, and human plasma. BI-94 stability in plasma can be only partially restored by acidifying it, which indicated other mechanisms in addition to pH for BI-94 instability in plasma.3. BI-94 formed adducts with the trapping agents, glutathione (GSH) and N-acetylcysteine (NAC), in vivo and in vitro via nucleophilic aromatic substitution reaction. The kinetics of adduct formation showed that neutral or physiological pHs enhanced and accelerated GSH and NAC adduct formation with BI-94, whereas acidic pHs prevented it. Therefore, physiological pHs not only altered BI-94 chemical stability but also enhanced adduct formation with endogenous nucleophiles. In addition, adduct formation with human serum albumin-peptide 3 (HSA-T3) at the Cys34 position was demonstrated.4. In conclusion, BI-94 was unstable at physiological conditions due to chemical instability and irreversible binding to plasma proteins.",
keywords = "Glutathione, LC-MS/MS, N-acetylcysteine, irreversible protein binding, isotopic filtering",
author = "Nagsen Gautam and Rhishikesh Thakare and Sandeep Rana and Amarnath Natarajan and Yazen Alnouti",
year = "2015",
month = "10",
day = "3",
doi = "10.3109/00498254.2015.1025250",
language = "English (US)",
volume = "45",
pages = "858--873",
journal = "Xenobiotica",
issn = "0049-8254",
publisher = "Informa Healthcare",
number = "10",

}

TY - JOUR

T1 - Irreversible binding of an anticancer compound (BI-94) to plasma proteins

AU - Gautam, Nagsen

AU - Thakare, Rhishikesh

AU - Rana, Sandeep

AU - Natarajan, Amarnath

AU - Alnouti, Yazen

PY - 2015/10/3

Y1 - 2015/10/3

N2 - 1. We investigated the mechanisms responsible for the in vivo instability of a benzofurazan compound BI-94 (NSC228148) with potent anti-cancer activity.2. BI-94 was stable in MeOH, water, and in various buffers at pHs 2.5-5, regardless of the buffer composition. In contrast, BI-94 was unstable in NaOH and at pHs 7-9, regardless of the buffer composition. BI-94 disappeared immediately after spiking into mice, rat, monkey, and human plasma. BI-94 stability in plasma can be only partially restored by acidifying it, which indicated other mechanisms in addition to pH for BI-94 instability in plasma.3. BI-94 formed adducts with the trapping agents, glutathione (GSH) and N-acetylcysteine (NAC), in vivo and in vitro via nucleophilic aromatic substitution reaction. The kinetics of adduct formation showed that neutral or physiological pHs enhanced and accelerated GSH and NAC adduct formation with BI-94, whereas acidic pHs prevented it. Therefore, physiological pHs not only altered BI-94 chemical stability but also enhanced adduct formation with endogenous nucleophiles. In addition, adduct formation with human serum albumin-peptide 3 (HSA-T3) at the Cys34 position was demonstrated.4. In conclusion, BI-94 was unstable at physiological conditions due to chemical instability and irreversible binding to plasma proteins.

AB - 1. We investigated the mechanisms responsible for the in vivo instability of a benzofurazan compound BI-94 (NSC228148) with potent anti-cancer activity.2. BI-94 was stable in MeOH, water, and in various buffers at pHs 2.5-5, regardless of the buffer composition. In contrast, BI-94 was unstable in NaOH and at pHs 7-9, regardless of the buffer composition. BI-94 disappeared immediately after spiking into mice, rat, monkey, and human plasma. BI-94 stability in plasma can be only partially restored by acidifying it, which indicated other mechanisms in addition to pH for BI-94 instability in plasma.3. BI-94 formed adducts with the trapping agents, glutathione (GSH) and N-acetylcysteine (NAC), in vivo and in vitro via nucleophilic aromatic substitution reaction. The kinetics of adduct formation showed that neutral or physiological pHs enhanced and accelerated GSH and NAC adduct formation with BI-94, whereas acidic pHs prevented it. Therefore, physiological pHs not only altered BI-94 chemical stability but also enhanced adduct formation with endogenous nucleophiles. In addition, adduct formation with human serum albumin-peptide 3 (HSA-T3) at the Cys34 position was demonstrated.4. In conclusion, BI-94 was unstable at physiological conditions due to chemical instability and irreversible binding to plasma proteins.

KW - Glutathione

KW - LC-MS/MS

KW - N-acetylcysteine

KW - irreversible protein binding

KW - isotopic filtering

UR - http://www.scopus.com/inward/record.url?scp=84940557888&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940557888&partnerID=8YFLogxK

U2 - 10.3109/00498254.2015.1025250

DO - 10.3109/00498254.2015.1025250

M3 - Article

C2 - 25869245

AN - SCOPUS:84940557888

VL - 45

SP - 858

EP - 873

JO - Xenobiotica

JF - Xenobiotica

SN - 0049-8254

IS - 10

ER -