Lysosomal dysfunction and autophagy blockade contribute to autophagy-related cancer suppressing peptide-induced cytotoxic death of cervical cancer cells through the AMPK/mTOR pathway

Abstract

Background Autophagy is an intracellular process through which intracellular components are recycled in response to nutrient or growth factor deficiency to maintain homeostasis. We identified the peptide autophagy-related cancer-suppressing peptide (ARCSP), a potential antitumor peptide that disrupts intracellular homeostasis by blocking autophagic flux and causes cytotoxic death. Methods The proliferative ability of ARCSP-treated cervical cancer cells was examined by the CCK8, EdU, and colony formation assays. The TUNEL assay was used to detect apoptosis. Mitochondrial function was evaluated based on the mitochondrial membrane potential. Autophagic flux was detected by immunofluorescence and confocal microscopy. The autophagy-related proteins AMPK, Raptor, mTOR, p62, LC3B, atg7, Rab7, LAMP1, LAMP2, and cathepsin D were detected by Immunoblotting. The antitumor effect of ARCSP was explored in vivo by establishing a transplant tumor model in nude mice. Results The results demonstrated that ARCSP induced cell death and inhibited proliferation. ARCSP induced AMPK/mTOR activation, resulting in the accumulation of the proteins LC3B, p62 and Atg7. ARCSP also blocked autophagosome-lysosome fusion by inhibiting endosomal maturation and increasing the lysosomal pH. The accumulation of nonfused autophagosomes exacerbated cytotoxic death, whereas knocking down Atg7 reversed the cytotoxic death induced by ARCSP. ARCSP-treated cells exhibited increased cytotoxic death after cotreatment with an autophagy inhibitor (Chloroquine CQ). Furthermore, the tumors of ARCSP-treated nude mice were significantly smaller than those of untreated mice. Conclusions Our findings demonstrate that ARCSP, a novel lethal nonfused autophagosome inducer, might cause mitochondrial dysfunction and autophagy-related cytotoxic death and is thus a prospective agent for cancer therapy.

Identification of Tumor Microenvironment and DNA Methylation-Related Prognostic Signature for Predicting Clinical Outcomes and Therapeutic Responses in Cervical Cancer

“…Many studies have found that the destruction of mTOR leads to the suppression of the cell cycle and angiogenesis, thereby inhibiting the development of cervical cancer. These studies also validated the reliability of our results ( Bossler et al, 2019 ; Sun et al, 2020 ; Yang et al, 2020 ).…”

Reactive Oxygen Species Mediate 6c-Induced Mitochondrial and Lysosomal Dysfunction, Autophagic Cell Death, and DNA Damage in Hepatocellular Carcinoma

“…The changes in lysosomal pH and cathepsin expression illustrated that the lysosomal functions were altered in the 6c-treated system. A recent paper reported that lysosomes are dysfunctional with the decreased expression of LAMP1 and LAMP2 [52]. Interestingly, the expression of LAMP1 and LAMP2 was increased after 6c treatment; however, the fluorescence intensity of AO (red), lyso-tracker, and DND-189 was reduced.…”

[6]-Gingerol Suppresses Oral Cancer Cell Growth by Inducing the Activation of AMPK and Suppressing the AKT/mTOR Signaling Pathway

“…There is evidence that AMPK inhibits the mTOR complex 1 (mTORC1) through the phosphorylation of the tuberous sclerosis complex protein-2 (TSC2) and raptor (36). Furthermore, the AMPK/mTOR pathway plays a crucial role in the progression of various tumors (9,11,37). For example, trifolirhizin induces colorectal cancer cell autophagy and apoptosis through activating AMPK and suppressing the mTOR pathway in vivo and in vitro (9).…”