Blocking AMPK/ULK1-dependent autophagy promoted apoptosis and suppressed colon cancer growth.

BACKGROUND: Autophagy is an evolutionarily conserved process through which cells degrade and recycle cytoplasm. The relation among autophagy, apoptosis and tumor is highly controversial until now and the molecular mechanism is poorly understood. METHODS: Cell viability and apoptosis were detected by CCK8, crystal violet staining, Hoechst333342 staining and flow cytometry. The expression of AMPK and ULK1 was analyzed by western blotting. Colon cancer growth suppression by NVP-BEZ235 or CQ in vivo was studied in a tumor xenograft mouse model. RESULTS: Our previous study revealed that NVP-BEZ235 suppressed colorectal cancer growth via inducing apoptosis, however later, we found it also initiated autophagy simultaneously. In this present study, our results show that NVP-BEZ235 induced autophagy through AMPK/ULK1 pathway in colon cancer cells. Blocking autophagy by knocking down AMPK or ULK1 inhibited cell proliferation and further promoted NVP-BEZ235 induced apoptosis. Meantime, the autophagy inhibitor chloroquine (CQ) shows obvious effect on inhibiting cell proliferation but not on inducing apoptosis, while it significantly increased NVP-BEZ235 induced apoptosis. Furthermore, the combinational therapy of NVP-BEZ235 and CQ shows synergistic antitumor effects in colon cancer in vivo. CONCLUSION: NVP-BEZ235 induced AMPK/ULK1-dependent autophagy. Targeting this autophagy suppressed colon cancer growth through further promoting apoptosis, which is a potential therapeutic option for clinical patients.

LncRNA CARMN m6A demethylation by ALKBH5 inhibits mutant p53-driven tumour progression through miR-5683/FGF2.

N-methyladenosine (m6A) represents a prevalent RNA modification observed in colorectal cancer. Despite its abundance, the biological implications of m6A methylation on the lncRNA CARMN remain elusive in colorectal cancer, especially for mutant p53 gain-of-function. Here, we elucidate that CARMN exhibits diminished expression levels in colorectal cancer patients with mutant p53, attributed to its rich m6A methylation, which promotes cancer proliferation, invasion and metastasis in vitro and in vivo. Further investigation illustrates that ALKBH5 acts as a direct demethylase of CARMN, targeting 477 methylation sites, thereby preserving CARMN expression. However, the interaction of mutant p53 with the ALKBH5 promoter impedes its transcription, enhancing m6A methylation levels on CARMN. Subsequently, YTHDF2/YTHDF3 recognise and degrade m6A-modified CARMN. Concurrently, overexpressing CARMN significantly suppressed colorectal cancer progression in vitro and in vivo. Additionally, miR-5683 was identified as a direct downstream target of lncRNA CARMN, exerting an antitumour effect by cooperatively downregulating FGF2 expression. Our findings revealed the regulator and functional mechanism of CARMN in colorectal cancer with mutant p53, potentially offering insights into demethylation-based strategies for cancer diagnosis and therapy. The m6A methylation of CARMN that is prime for mutant p53 gain-of-function-induced malignant progression of colorectal cancer, identifying a promising approach for cancer therapy.

Prefrontal brain activity and self-injurious behavior in adolescents with major depressive disorder: A functional near-infrared spectroscopy (fNIRS) study.

In clinical practice, accurately identifying self-injurious behavior among adolescents with major depressive disorder (MDD) is crucial for individualized treatment. This study aimed to examine the differences in prefrontal cortex activation using the functional near-infrared spectroscopy (fNIRS) during the verbal fluency task (VFT) assessment of adolescents with MDD and self-harm (SH) compared with those without SH. A total of 60 eligible patients were included for final analysis, with the SH group containing 36 participants, and the Non-SH group containing 24 participants. We found that right middle frontal gyrus (rMFG) was more activated in the SH group than that in the Non-SH group during the VFT assessments (z = -3.591, p = 0.004, FDR correction). The z-scores of beta values of rMFG exhibited a good discriminatory power with the area under the curve (AUC) in distinguishing the two groups (AUC = 0.775, p < 0.001). These findings reveal that the fNIRS-VFT paradigm may be a useful tool for discovering neurobiological differences among adolescents with MDD.

In situ injectable hydrogel-loaded drugs induce anti-tumor immune responses in melanoma immunochemotherapy.

Melanoma is a highly aggressive tumor located in the skin, with limited traditional therapies. In order to reduce the side effects caused by traditional administration method and amplify the killing effect of immune system against tumor cells, an in situ injectable hydrogel drug delivery system is developed for the first time which co-delivers doxorubicin (Dox) and imiquimod (R837) for the synergistic therapy of melanoma. The mechanical properties and stability of the hydrogel are characterized and the optimal doses of hydrogel and drugs are also identified. As a result, the co-delivery system effectively suppresses melanoma growth and metastatic progression both in vitro and in vivo. Further studies show that the co-delivery system causes immunogenic cell death, activation of antigen presenting cells, comprising dendritic cells and M1 macrophages, and secretion of related cytokines consisted of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), subsequently with the activation of T lymphocytes and natural killer cells in spleen and tumor area. The co-delivery system also decreases the suppressive immune responses, including infiltration of M2 macrophages and secretion of interleukin-10 (IL-10), in vivo. Besides, other death modes are induced by the co-delivery system, including apoptosis and non-apoptotic cell death. In a word, this co-delivery system induces melanoma cell death directly and activates immune system for further tumor killing simultaneously, which shows probability for precise targeted tumor therapy.

Mutant p53 drives cancer chemotherapy resistance due to loss of function on activating transcription of PUMA.

P53 is a critical tumor suppressor gene, activating p53 and its downstream targets to induce apoptosis is a promising way for cancer therapy. However, more than 50% of cancer patients have p53 mutations, which may cause cancer therapy resistance, and the underline mechanism is poorly understood. Here, we found that cell viability decrease and apoptosis induced by p53-dependent traditional drugs in colon cancer cells were eliminated in p53 mutant cells. Mutant p53 did not up-regulate the expression of its direct downstream targets PUMA and p21, due to the inhibition of PUMA transcription. Furthermore, mutant p53 could not bind to the promoter of PUMA to activate its transcription like WT p53 did, while overexpressed WT p53 rescued PUMA-induced subsequent apoptosis. In conclusion, our findings demonstrate mutant p53 may cause chemo-resistance of tumor because of inactivating PUMA transcription, which prompts some new insights for clinical therapy of cancer patients with mutant p53.Abbreviations: CRC: Colorectal cancer; CDKs: Cyclin-dependent kinases; PUMA: p53 up-regulated modulator of apoptosis; PDGF: the platelet-derived growth factor; WT p53: wild-type p53 protein; mutp53: mutant p53 proteins; BAX: Bcl-2-associated X protein; NOXA: Phorbol-12-myristate-13-acetate-induced protein 1.