Limits...
Inhibition of ERBB2-overexpressing Tumors by Recombinant Human Prolidase and Its Enzymatically Inactive Mutant.

Yang L, Li Y, Bhattacharya A, Zhang Y - EBioMedicine (2015)

Bottom Line: ERBB2 is an oncogenic receptor tyrosine kinase overexpressed in a subset of human breast cancer and other cancers.We recently found that human prolidase (PEPD), a dipeptidase, is a high affinity ERBB2 ligand and cross-links two ERBB2 monomers.Several anti-ERBB2 agents are on the market but are hampered by drug resistance and high drug cost. rhPEPD(G278D) may synergize with these agents and may also be highly cost-effective, since it targets ERBB2 with a different mechanism and can be produced in bacteria.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemoprevention, Roswell Park Cancer Institute, Buffalo, NY 14263, United States.

ABSTRACT

ERBB2 is an oncogenic receptor tyrosine kinase overexpressed in a subset of human breast cancer and other cancers. We recently found that human prolidase (PEPD), a dipeptidase, is a high affinity ERBB2 ligand and cross-links two ERBB2 monomers. Here, we show that recombinant human PEPD (rhPEPD) strongly inhibits ERBB2-overexpressing tumors in mice, whereas it does not impact tumors without ERBB2 overexpression. rhPEPD causes ERBB2 depletion, disrupts oncogenic signaling orchestrated by ERBB2 homodimers and heterodimers, and induces apoptosis. The impact of enzymatically-inactive mutant rhPEPD(G278D) on ERBB2 is indistinguishable from that of rhPEPD, but rhPEPD(G278D) is superior to rhPEPD for tumor inhibition. The enzymatic function of rhPEPD stimulates HIF-1α and other pro-survival factors in tumors, which likely attenuates its antitumor activity. rhPEPD(G278D) is also attractive in that it may not interfere with the physiologic function of endogenous PEPD in normal cells. Collectively, we have identified a human protein as an inhibitory ERBB2 ligand that inhibits ERBB2-overexpressing tumors in vivo. Several anti-ERBB2 agents are on the market but are hampered by drug resistance and high drug cost. rhPEPD(G278D) may synergize with these agents and may also be highly cost-effective, since it targets ERBB2 with a different mechanism and can be produced in bacteria.

No MeSH data available.


Related in: MedlinePlus

rhPEPDG278D is superior to rhPEPD for combating ErbB2-overexpressing tumors. [A] Sizes of orthotopic BT-474 tumors with no treatment, upon treatment with EP, EP plus rhPEPD, or EP plus rhPEPDG278D, during treatment pause, and upon retreatment with EP, or EP plus rhPEPDG278D. All treatment days are relative to the day of cancer cell inoculation. EP was administered to the mice i.p. at 0.5 mg/kg daily, starting 4 days before rhPEPD or rhPEPDG278D. rhPEPD or rhPEPDG278D was administered to the mice i.p. at 2 mg/kg; during the initial phase of treatment, each agent was administered thrice weekly (Monday, Wednesday and Friday); during the retreatment phase, rhPEPDG278D was administered every 2–3 days. The tumor growth curves in mice treated initially with EP plus rhPEPD or EP plus rhPEPDG278D were redrawn on tumor growth day 83 into those with relapse or with CR. Error bars are SEM (n = 6 in no treatment group; n = 10–12 in all other groups during the initial phase of treatment; n = 4–8 during the second phase of treatment). *tumors were removed and photographed 2 days before the other tumors. Scale bars: 3 cm. [B] Plasma levels of PEPD (endogenous PEPD, rhPEPD and/or rhPEPDG278D) at 24 h after the last dose during the initial phase of treatment. Error bars are SD (n = 3). [C] Scatter plots of plasma levels of sERBB2 at 24 h after the last dose during the initial phase of treatment; 3–6 samples per group.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4465122&req=5

f0010: rhPEPDG278D is superior to rhPEPD for combating ErbB2-overexpressing tumors. [A] Sizes of orthotopic BT-474 tumors with no treatment, upon treatment with EP, EP plus rhPEPD, or EP plus rhPEPDG278D, during treatment pause, and upon retreatment with EP, or EP plus rhPEPDG278D. All treatment days are relative to the day of cancer cell inoculation. EP was administered to the mice i.p. at 0.5 mg/kg daily, starting 4 days before rhPEPD or rhPEPDG278D. rhPEPD or rhPEPDG278D was administered to the mice i.p. at 2 mg/kg; during the initial phase of treatment, each agent was administered thrice weekly (Monday, Wednesday and Friday); during the retreatment phase, rhPEPDG278D was administered every 2–3 days. The tumor growth curves in mice treated initially with EP plus rhPEPD or EP plus rhPEPDG278D were redrawn on tumor growth day 83 into those with relapse or with CR. Error bars are SEM (n = 6 in no treatment group; n = 10–12 in all other groups during the initial phase of treatment; n = 4–8 during the second phase of treatment). *tumors were removed and photographed 2 days before the other tumors. Scale bars: 3 cm. [B] Plasma levels of PEPD (endogenous PEPD, rhPEPD and/or rhPEPDG278D) at 24 h after the last dose during the initial phase of treatment. Error bars are SD (n = 3). [C] Scatter plots of plasma levels of sERBB2 at 24 h after the last dose during the initial phase of treatment; 3–6 samples per group.

Mentions: We next turned to orthotopic BT-474 tumors. Human breast cancer BT-474 cells constitutively overexpress ERBB2 but also express a low level of ERBB1 and ERBB3 (Yang et al., 2014). rhPEPD dose was escalated to 2 mg/kg thrice weekly, in view of its performance in CHO-K1/ERBB2 tumors. EP dose was lowered to 0.5 mg/kg daily, which was adequate for sustaining blood PEPD level (Supplementary Fig. 3). rhPEPDG278D, an enzymatically inactive mutant (Ledoux et al., 1996), was also evaluated. EP had no effect on BT-474 tumor, but tumor began to shrink after the first dose of rhPEPD or rhPEPDG278D, and the remaining tumors were consistently smaller in the rhPEPDG278D-treated mice than in rhPEPD-treated mice during the treatment period (P = 0.0003, Fig. 2A). Plasma rhPEPDG278D concentration was 16.8% (25.9/154.5) lower than that of rhPEPD at 24 h after the final treatment, albeit not statistically significant (Fig. 2B). Plasma sERBB2 concentrations decreased greatly after treatment with rhPEPD or rhPEPDG278D and were undetectable in 50% (3/6) rhPEPD-treated mice and 67% (4/6) rhPEPDG278D-treated mice (Fig. 2C). Initial treatments lasted 30 days, with 27.3% (3/11) of rhPEPD-treated tumors and 41.7% (5/12) of rhPEPDG278D-treated tumors achieving complete remission (CR) (Fig. 2A; Supplementary Fig. 4A and B). Nearly all of the tumors in partial remission relapsed by approximately 25 days after treatment termination; however, these tumors were still exquisitely sensitive to rhPEPDG278D (Fig. 2A), indicating that tumor relapsed due to incomplete initial treatment but not due to the presence of rhPEPD/rhPEPDG278D-resistant cells. Moreover, very large tumors (~ 500 mm3) also responded exquisitely to rhPEPDG278D (Fig. 2A). The experiment was stopped due to heavy tumor burden in the mice treated by EP alone. Molecular changes in the tumor tissues could not be determined, because tumors in some treatment groups were extremely small or no longer present. There were no signs of adverse effects in the mice treated by rhPEPD or rhPEPDG278D. Neither rhPEPD nor rhPEPDG278D impacted animal body weight gain, the weights of major organs or heart histology (Supplementary Fig. 4C–E). Notably, cardiotoxicity occurs in some patients receiving anti-ERBB2 therapies (Sendur et al., 2013).


Inhibition of ERBB2-overexpressing Tumors by Recombinant Human Prolidase and Its Enzymatically Inactive Mutant.

Yang L, Li Y, Bhattacharya A, Zhang Y - EBioMedicine (2015)

rhPEPDG278D is superior to rhPEPD for combating ErbB2-overexpressing tumors. [A] Sizes of orthotopic BT-474 tumors with no treatment, upon treatment with EP, EP plus rhPEPD, or EP plus rhPEPDG278D, during treatment pause, and upon retreatment with EP, or EP plus rhPEPDG278D. All treatment days are relative to the day of cancer cell inoculation. EP was administered to the mice i.p. at 0.5 mg/kg daily, starting 4 days before rhPEPD or rhPEPDG278D. rhPEPD or rhPEPDG278D was administered to the mice i.p. at 2 mg/kg; during the initial phase of treatment, each agent was administered thrice weekly (Monday, Wednesday and Friday); during the retreatment phase, rhPEPDG278D was administered every 2–3 days. The tumor growth curves in mice treated initially with EP plus rhPEPD or EP plus rhPEPDG278D were redrawn on tumor growth day 83 into those with relapse or with CR. Error bars are SEM (n = 6 in no treatment group; n = 10–12 in all other groups during the initial phase of treatment; n = 4–8 during the second phase of treatment). *tumors were removed and photographed 2 days before the other tumors. Scale bars: 3 cm. [B] Plasma levels of PEPD (endogenous PEPD, rhPEPD and/or rhPEPDG278D) at 24 h after the last dose during the initial phase of treatment. Error bars are SD (n = 3). [C] Scatter plots of plasma levels of sERBB2 at 24 h after the last dose during the initial phase of treatment; 3–6 samples per group.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465122&req=5

f0010: rhPEPDG278D is superior to rhPEPD for combating ErbB2-overexpressing tumors. [A] Sizes of orthotopic BT-474 tumors with no treatment, upon treatment with EP, EP plus rhPEPD, or EP plus rhPEPDG278D, during treatment pause, and upon retreatment with EP, or EP plus rhPEPDG278D. All treatment days are relative to the day of cancer cell inoculation. EP was administered to the mice i.p. at 0.5 mg/kg daily, starting 4 days before rhPEPD or rhPEPDG278D. rhPEPD or rhPEPDG278D was administered to the mice i.p. at 2 mg/kg; during the initial phase of treatment, each agent was administered thrice weekly (Monday, Wednesday and Friday); during the retreatment phase, rhPEPDG278D was administered every 2–3 days. The tumor growth curves in mice treated initially with EP plus rhPEPD or EP plus rhPEPDG278D were redrawn on tumor growth day 83 into those with relapse or with CR. Error bars are SEM (n = 6 in no treatment group; n = 10–12 in all other groups during the initial phase of treatment; n = 4–8 during the second phase of treatment). *tumors were removed and photographed 2 days before the other tumors. Scale bars: 3 cm. [B] Plasma levels of PEPD (endogenous PEPD, rhPEPD and/or rhPEPDG278D) at 24 h after the last dose during the initial phase of treatment. Error bars are SD (n = 3). [C] Scatter plots of plasma levels of sERBB2 at 24 h after the last dose during the initial phase of treatment; 3–6 samples per group.
Mentions: We next turned to orthotopic BT-474 tumors. Human breast cancer BT-474 cells constitutively overexpress ERBB2 but also express a low level of ERBB1 and ERBB3 (Yang et al., 2014). rhPEPD dose was escalated to 2 mg/kg thrice weekly, in view of its performance in CHO-K1/ERBB2 tumors. EP dose was lowered to 0.5 mg/kg daily, which was adequate for sustaining blood PEPD level (Supplementary Fig. 3). rhPEPDG278D, an enzymatically inactive mutant (Ledoux et al., 1996), was also evaluated. EP had no effect on BT-474 tumor, but tumor began to shrink after the first dose of rhPEPD or rhPEPDG278D, and the remaining tumors were consistently smaller in the rhPEPDG278D-treated mice than in rhPEPD-treated mice during the treatment period (P = 0.0003, Fig. 2A). Plasma rhPEPDG278D concentration was 16.8% (25.9/154.5) lower than that of rhPEPD at 24 h after the final treatment, albeit not statistically significant (Fig. 2B). Plasma sERBB2 concentrations decreased greatly after treatment with rhPEPD or rhPEPDG278D and were undetectable in 50% (3/6) rhPEPD-treated mice and 67% (4/6) rhPEPDG278D-treated mice (Fig. 2C). Initial treatments lasted 30 days, with 27.3% (3/11) of rhPEPD-treated tumors and 41.7% (5/12) of rhPEPDG278D-treated tumors achieving complete remission (CR) (Fig. 2A; Supplementary Fig. 4A and B). Nearly all of the tumors in partial remission relapsed by approximately 25 days after treatment termination; however, these tumors were still exquisitely sensitive to rhPEPDG278D (Fig. 2A), indicating that tumor relapsed due to incomplete initial treatment but not due to the presence of rhPEPD/rhPEPDG278D-resistant cells. Moreover, very large tumors (~ 500 mm3) also responded exquisitely to rhPEPDG278D (Fig. 2A). The experiment was stopped due to heavy tumor burden in the mice treated by EP alone. Molecular changes in the tumor tissues could not be determined, because tumors in some treatment groups were extremely small or no longer present. There were no signs of adverse effects in the mice treated by rhPEPD or rhPEPDG278D. Neither rhPEPD nor rhPEPDG278D impacted animal body weight gain, the weights of major organs or heart histology (Supplementary Fig. 4C–E). Notably, cardiotoxicity occurs in some patients receiving anti-ERBB2 therapies (Sendur et al., 2013).

Bottom Line: ERBB2 is an oncogenic receptor tyrosine kinase overexpressed in a subset of human breast cancer and other cancers.We recently found that human prolidase (PEPD), a dipeptidase, is a high affinity ERBB2 ligand and cross-links two ERBB2 monomers.Several anti-ERBB2 agents are on the market but are hampered by drug resistance and high drug cost. rhPEPD(G278D) may synergize with these agents and may also be highly cost-effective, since it targets ERBB2 with a different mechanism and can be produced in bacteria.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemoprevention, Roswell Park Cancer Institute, Buffalo, NY 14263, United States.

ABSTRACT

ERBB2 is an oncogenic receptor tyrosine kinase overexpressed in a subset of human breast cancer and other cancers. We recently found that human prolidase (PEPD), a dipeptidase, is a high affinity ERBB2 ligand and cross-links two ERBB2 monomers. Here, we show that recombinant human PEPD (rhPEPD) strongly inhibits ERBB2-overexpressing tumors in mice, whereas it does not impact tumors without ERBB2 overexpression. rhPEPD causes ERBB2 depletion, disrupts oncogenic signaling orchestrated by ERBB2 homodimers and heterodimers, and induces apoptosis. The impact of enzymatically-inactive mutant rhPEPD(G278D) on ERBB2 is indistinguishable from that of rhPEPD, but rhPEPD(G278D) is superior to rhPEPD for tumor inhibition. The enzymatic function of rhPEPD stimulates HIF-1α and other pro-survival factors in tumors, which likely attenuates its antitumor activity. rhPEPD(G278D) is also attractive in that it may not interfere with the physiologic function of endogenous PEPD in normal cells. Collectively, we have identified a human protein as an inhibitory ERBB2 ligand that inhibits ERBB2-overexpressing tumors in vivo. Several anti-ERBB2 agents are on the market but are hampered by drug resistance and high drug cost. rhPEPD(G278D) may synergize with these agents and may also be highly cost-effective, since it targets ERBB2 with a different mechanism and can be produced in bacteria.

No MeSH data available.


Related in: MedlinePlus