Cryptotanshinone-Induced p53-Dependent Sensitization of Colon Cancer Cells to Apoptotic Drive by Regulation of Calpain and Calcium Homeostasis

Yue Wang, Zhu Zhang, Kathy K W AU YEUNG, Chi Hin Cho, Kin Lam YUNG, Joshua KO*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Over-expression of calpains in tumor tissues can be associated with cancer progression. Thus, inhibition of calpain activity using specific inhibitors has become a novel approach to control tumor growth. In this study, the anticancer potential of cryptotanshinone in combination with calpain inhibitor had been investigated in colon cancer cells and tumor xenograft. Cryptotanshinone elicited an initial endoplasmic reticular (ER) stress response, whereas prolonged stress would result in the promotion of apoptosis. It was then discovered that cryptotanshinone could cause rapid and sustained increase in cytosolic calcium in colon cancer cells accompanied by early GRP78 overexpression, which could be attenuated by pre-treatment of the calcium chelator BAPTA-AM. Cryptotanshinone also facilitated an early increase in calpain activity, which could be blocked by BAPTA-AM or the calpain inhibitor PD150606. A dynamic interaction between GRP78 and calpain during the action of cryptotanshinone was unveiled. This together with the altered NF-κB signaling could be abolished by calpain inhibitor. GRP78 knockdown increased the sensitivity of cancer cells to cryptotanshinone-evoked apoptosis and reduction of cancer cell colony formation. Such sensitization of drug action had been confirmed to be p53-dependent by using p53-mutated (HT-29) and p53-deficient (HCT116 p53-) cells. The synergistic antitumor effect of cryptotanshinone and calpain inhibitor was further exhibited in vivo. Taken together, findings in this study exemplify a new chemotherapeutic regimen comprising cryptotanshinone and calpain inhibitor by regulation of calpain and calcium homeostasis. This has provided us with new insights in the search of a potential target-specific neoadjuvant therapy against colon cancer.

Original languageEnglish
Pages (from-to)1179-1202
Number of pages24
JournalAmerican Journal of Chinese Medicine
Volume48
Issue number5
DOIs
Publication statusPublished - 2020

Scopus Subject Areas

  • Complementary and alternative medicine

User-Defined Keywords

  • Apoptosis
  • Calcium Homeostasis
  • Calpain Inhibitor
  • Colon Cancer
  • Cryptotanshinone
  • ER Stress
  • p53

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