Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jan-Feb;39(1):102-109.
doi: 10.21873/invivo.13807.

The Combination of Tumor-targeting Salmonella typhimurium A1-R Plus the Autophagy-inhibitor Chloroquine Synergistically Eradicates HT1080 Fibrosarcoma Cells In Vitro and In Vivo

Sei Morinaga  1   2   3 , Ming Zhao  1 , Kohei Mizuta  1   2 , Byung Mo Kang  1   2 , Michael Bouvet  2 , Norio Yamamoto  3 , Katsuhiro Hayashi  3 , Hiroaki Kimura  3 , Shinji Miwa  3 , Kentaro Igarashi  3 , Takashi Higuchi  3 , Hiroyuki Tsuchiya  3 , Satoru Demura  3 , Robert M Hoffman  4   2
Affiliations

The Combination of Tumor-targeting Salmonella typhimurium A1-R Plus the Autophagy-inhibitor Chloroquine Synergistically Eradicates HT1080 Fibrosarcoma Cells In Vitro and In Vivo

Sei Morinaga et al. In Vivo. 2025 Jan-Feb.

Abstract

Background/aim: Salmonella typhimurium A1-R (A1-R) targets and inhibits a wide range of cancer types without continuously infecting healthy tissue. Chloroquine, an antimalarial drug, induces apoptosis and inhibits autophagy in cancer cells. The aim of the present study was to determine the synergy of A1-R plus chloroquine on HT1080 human fibrosarcoma cells in vitro and in a nude-mouse model.

Materials and methods: HT1080 human fibrosarcoma cells were used for in vitro experiments. Four groups were analysed in vitro: No-treatment control; A1-R; chloroquine; A1-R plus chloroquine. The nude-mouse models of HT1080 human fibrosarcoma were randomly assigned into four groups: G1: untreated control; G2: Oral A1-R [5×107 colony forming units (CFU)/body, twice a week, 2 weeks]; G3: Chloroquine [100 mg/kg/body, intraperitoneal (IP) administration, twice a week, 2 weeks]; G4: Oral A1-R (5×107 CFU/body), twice a week, 2 weeks plus chloroquine (100 mg/kg/body, IP), twice a week, 2 weeks. Each cohort consisted of five mice. Tumor volume and body weight were assessed biweekly.

Results: A1-R combined with chloroquine synergistically decreased the viability of HT1080 cells in vitro compared to other groups. Orally-administered A1-R at 5×107 CFU combined with IP-administered chloroquine eradicated HT1080 tumors in nude mice, without body-weight decrease.

Conclusion: The combination treatment of A1-R plus chloroquine demonstrated synergy against HT1080 cancer cells in vitro and in vivo. A1-R was administered orally, suggesting its potential as a probiotic. The present results suggest the clinical potential of the combination of A1-R and chloroquine for soft-tissue sarcoma therapy, a recalcitrant disease.

Keywords: Salmonella typhimurium A1-R; autophagy-inhibitor; chloroquine; combination; fibrosarcoma; nude mice; oral administration; synergy HT1080; tumor eradication.

PubMed Disclaimer

Conflict of interest statement

The Authors declare no competing interests in relation to this study.

Figures

Figure 1
Figure 1
IC50 determination of Salmonella typhimurium A1-R (A1-R) and chloroquine on the viability of HT1080 cells (mean±SD). A) IC50 of A1-R on HT1080 cells. B) IC50 of chloroquine on HT1080 cells.
Figure 2
Figure 2
Efficacy of the combination of Salmonella typhimurium A1-R (A1-R) plus chloroquine in inhibiting the viability of HT1080 cells in vitro. The combination of A1-R (0.53×106 CFU/ml [IC50]) and chloroquine (40.7 μM [IC50]) was synergistic against the viability of HT1080 cells (*p<0.05).
Figure 3
Figure 3
Efficacy of Salmonella typhimurium A1-R (A1-R) and chloroquine on HT1080 tumor growth. (A) Time course efficacy of A1-R and chloroquine alone and in combination on HT1080 human fibrosarcoma tumors in nude mice. (B) HT1080 human fibrosarcoma tumor volume on day 14 of treatment with A1-R and chloroquine alone, and in combination, on nude mice. Data are shown as the mean±standard deviation. A1-R was administered PO by gavage at 5×107 CFU in 100 μL PBS twice per week. Chloroquine was administered IP at 100 mg/kg, twice per week.
Figure 4
Figure 4
Images of HT1080-tumors in nude mice on day 14 of treatment with Salmonella typhimurium A1-R (A1-R) and chloroquine alone, and in combination. White arrows indicate remaining tumors. The combination of A1-R plus chloroquine eradicated the tumor. Please see Materials & Methods for dosing details.
Figure 5
Figure 5
Effect of treatment with A1-R and chloroquine alone, and in combination on body weight of nude mice with HT1080 human-fibrosarcoma tumors. Data are shown as the mean±standard deviation. Please see the Materials and Methods for dosing details.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Zhao M, Yang M, Li XM, Jiang P, Baranov E, Li S, Xu M, Penman S, Hoffman RM. Tumor-targeting bacterial therapy with amino acid auxotrophs of GFP-expressing Salmonella typhimurium. Proc Natl Acad Sci U S A. 2005;102(3):755–760. doi: 10.1073/pnas.0408422102. - DOI - PMC - PubMed
    1. Zhao M, Yang M, Ma H, Li X, Tan X, Li S, Yang Z, Hoffman RM. Targeted therapy with a Salmonella typhimurium leucine-arginine auxotroph cures orthotopic human breast tumors in nude mice. Cancer Res. 2006;66(15):7647–7652. doi: 10.1158/0008-5472.CAN-06-0716. - DOI - PubMed
    1. Zhao M, Geller J, Ma H, Yang M, Penman S, Hoffman RM. Monotherapy with a tumor-targeting mutant of Salmonella typhimurium cures orthotopic metastatic mouse models of human prostate cancer. Proc Natl Acad Sci U.S.A. 2007;104(24):10170–10174. doi: 10.1073/pnas.0703867104. - DOI - PMC - PubMed
    1. Zhang Y, Tome Y, Suetsugu A, Zhang L, Zhang N, Hoffman RM, Zhao M. Determination of the optimal route of administration of Salmonella typhimurium A1-R to target breast cancer in nude mice. Anticancer Res. 2012;32:2501–2508. - PubMed
    1. Zhang Y, Miwa S, Zhang N, Hoffman RM, Zhao M. Tumor-targeting Salmonella typhimurium A1-R arrests growth of breast-cancer brain metastasis. Oncotarget. 2015;6(5):2615–2622. doi: 10.18632/oncotarget.2811. - DOI - PMC - PubMed

LinkOut - more resources