Human bronchial carcinoid tumor initiating cells are targeted by the combination of acetazolamide and sulforaphane

Reza Bayat Mokhtari, Narges Baluch, Evgeniya Morgatskaya, Sushil Kumar, Angelo Sparaneo, Lucia Anna Muscarella, Sheyun Zhao, Hai Ling Cheng, Bikul Das, Herman Yeger

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Background: Bronchial carcinoids are neuroendocrine tumors that present as typical (TC) and atypical (AC) variants, the latter being more aggressive, invasive and metastatic. Studies of tumor initiating cell (TIC) biology in bronchial carcinoids has been hindered by the lack of appropriate in-vitro and xenograft models representing the bronchial carcinoid phenotype and behavior. Methods: Bronchial carcinoid cell lines (H727, TC and H720, AC) were cultured in serum-free growth factor supplemented medium to form 3D spheroids and serially passaged up to the 3rd generation permitting expansion of the TIC population as verified by expression of stemness markers, clonogenicity in-vitro and tumorigenicity in both subcutaneous and orthotopic (lung) models. Acetazolamide (AZ), sulforaphane (SFN) and the AZ + SFN combination were evaluated for targeting TIC in bronchial carcinoids. Results: Data demonstrate that bronchial carcinoid cell line 3rd generation spheroid cells show increased drug resistance, clonogenicity, and tumorigenic potential compared with the parental cells, suggesting selection and expansion of a TIC fraction. Gene expression and immunolabeling studies demonstrated that the TIC expressed stemness factors Oct-4, Sox-2 and Nanog. In a lung orthotopic model bronchial carcinoid, cell line derived spheroids, and patient tumor derived 3rd generation spheroids when supported by a stroma, showed robust tumor formation. SFN and especially the AZ + SFN combination were effective in inhibiting tumor cell growth, spheroid formation and in reducing tumor formation in immunocompromised mice. Conclusions: Human bronchial carcinoid tumor cells serially passaged as spheroids contain a higher fraction of TIC exhibiting a stemness phenotype. This TIC population can be effectively targeted by the combination of AZ + SFN. Our work portends clinical relevance and supports the therapeutic use of the novel AZ+ SFN combination that may target the TIC population of bronchial carcinoids.

Original languageEnglish (US)
Article number864
JournalBMC cancer
Issue number1
StatePublished - Aug 30 2019


  • 3D spheroids
  • Acetazolamide
  • Bronchial carcinoid
  • Combination therapy
  • Orthotopic lung model
  • Sulforaphane

ASJC Scopus subject areas

  • Oncology
  • Genetics
  • Cancer Research


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