Erianin,a novel dibenzyl compound in Dendrobium extract,inhibits lung cancer cell growth and migration via calcium/calmodulin-dependent ferroptosis

Ferroptosis,a novel form of programmed cell death,is characterized by iron-dependent lipid peroxidation and has been shown to be involved in multiple diseases,including cancer.Stimulating ferroptosis in cancer cells may be a potential strategy for cancer therapy.Therefore,ferroptosis-inducing drugs are attracting more attention for cancer treatment.Here,we showed that erianin,a natural product isolated from Dendrobium chrysotoxum Lindl,exerted its anticancer activity by inducing cell death and inhibiting cell migration in lung cancer cells.Subsequently,we demonstrated for the first time that erianin induced ferroptotic cell death in lung cancer cells,which was accompanied by ROS accumulation,lipid peroxidation,and GSH depletion.The ferroptosis inhibitors Fer-1 and Lip-1 but not Z-VAD-FMK,CQ,or necrostatin-1 rescued erianin-induced cell death,indicating that ferroptosis contributed to erianin-induced cell death.Furthermore,we demonstrated that Ca^(2+)/CaM signaling was a critical mediator of erianin-induced ferroptosis and that blockade of this signaling significantly rescued cell death induced by erianin treatment by suppressing ferroptosis.Taken together,our data suggest that the natural product erianin exerts its anticancer effects by inducing Ca^(2+)/CaMdependent ferroptosis and inhibiting cell migration,and erianin will hopefully serve as a prospective compound for lung cancer treatment.

PCDH17 increases the sensitivity of colorectal cancer to 5-fluorouracil treatment by inducing apoptosis and autophagic cell death

5-Fluorouracil(5-FU)is known as a first-line chemotherapeutic agent against colorectal cancer(CRC),but drug resistance occurs frequently and significantly limits its clinical success.Our previous study showed that the protocadherin 17(PCDH17)gene was frequently methylated and functioned as a tumor suppressor in CRC.However,the relationship between PCDH17 and 5-FU resistance in CRC remains unclear.Here,we revealed that PCDH17 was more highly expressed in 5-FU-sensitive CRC tissues than in 5-FU-resistant CRC tissues,and high expression of PCDH17 was correlated with high BECN1 expression.Moreover,this expression profile contributed to superior prognosis and increased survival in CRC patients.Restoring PCDH17 expression augmented the 5-FU sensitivity of CRC in vitro and in vivo by promoting apoptosis and autophagic cell death.Furthermore,autophagy played a dominant role in PCDH17-induced cell death,as an autophagy inhibitor blocked cell death to a greater extent than the pancaspase inhibitor Z-VAD-FMK.PCDH17 inhibition by siRNA decreased the autophagy response and 5-FU sensitivity.Mechanistically,we showed that c-Jun NH2-terminal kinase(JNK)activation was a key determinant in PCDH17-induced autophagy.The compound SP600125,an inhibitor of JNK,suppressed autophagy and 5-FU-induced cell death in PCDH17-reexpressing CRC cells.Taken together,our findings suggest for the first time that PCDH17 increases the sensitivity of CRC to 5-FU treatment by inducing apoptosis and JNK-dependent autophagic cell death.PCDH17 may be a potential prognostic marker for predicting 5-FU sensitivity in CRC patients.