Related Experiment Video

Updated: Oct 18, 2025

siRNA Electroporation to Modulate Autophagy in Herpes Simplex Virus Type 1-Infected Monocyte-Derived Dendritic Cells

siRNA Electroporation to Modulate Autophagy in Herpes Simplex Virus Type 1-Infected Monocyte-Derived Dendritic Cells

Published on: October 28, 2019

Rapalogs induce non-apoptotic, autophagy-dependent cell death in HPV-negative TP53 mutant head and neck squamous cell

Md Maksudul Alam¹, Janmaris Marin Fermin¹, Patrick T Spiller¹

¹Department of Otolaryngology-Head and Neck Surgery, LSU-Health Sciences Center, Shreveport, Louisiana, USA.

Molecular Carcinogenesis

|October 1, 2021

Abstract:

TP53 is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSCC). Patients with HPV-negative TP53 mutant HNSCC have the worst prognosis, necessitating additional agents for treatment. Since mutant p53 causes sustained activation of the PI3K/AKT/mTOR signaling pathway, we investigated the effect of rapalogs RAD001 and CCI-779 on HPV-negative mutTP53 HNSCC cell lines and xenografts. Rapalogs significantly reduced cell viability and colony formation. Interestingly, rapalogs-induced autophagy with no effect on apoptosis. Pretreatment with autophagy inhibitors, 3-methyladenine (3-MA) and ULK-101 rescued the cell viability by inhibiting rapalog-induced autophagy, suggesting that both RAD001 and CCI-779 induce non-apoptotic autophagy-dependent cell death (ADCD). Moreover, rapalogs upregulated the levels of ULK1 and pULK1 S555 with concomitant downregulation of the mTORC1 pathway. However, pretreatment of cells with rapalogs prevented the ULK-101-mediated inhibition of ULK1 to sustained autophagy, suggesting that rapalogs induce ADCD through the activation of ULK1. To further translate our in vitro studies, we investigated the effect of RAD001 in HPV-negative mutTP53 (HN31 and FaDu) tumor cell xenograft model in nude mice. Mice treated with RAD001 exhibited a significant tumor volume reduction without induction of apoptosis, and with a concomitant increase in autophagy. Further, treatment with RAD001 was associated with a considerable increase in pULK1 S555 and ULK1 levels through the inhibition of mTORC1. 3-MA reversed the effect of RAD001 on FaDu tumor growth suggesting that RAD001 promotes ACDC in HPV-negative mutTP53 xenograft. This is the first report demonstrating that rapalogs promote non-apoptotic ADCD in HPV-negative mutTP53 HNSCC via the ULK1 pathway. Further studies are required to establish the promising role of rapalogs in preventing the regrowth of HPV-negative mutTP53 HNSCC.

Insights

Rapalogs like RAD001 and CCI-779 induce autophagy-dependent cell death (ADCD) in HPV-negative TP53 mutant head and neck squamous cell carcinoma (HNSCC). This study shows rapalogs activate ULK1, promoting non-apoptotic cell death in HNSCC.

Area of Science:

Oncology
Molecular Biology
Cancer Research

Background:

TP53 mutations are common in head and neck squamous cell carcinoma (HNSCC), particularly in HPV-negative cases with poor prognosis.
Mutant p53 protein sustains PI3K/AKT/mTOR pathway activation, presenting a therapeutic target.

Purpose of the Study:

To investigate the efficacy of rapalogs (RAD001, CCI-779) in HPV-negative TP53 mutant HNSCC.
To elucidate the mechanism of rapalog-induced cell death, focusing on autophagy and apoptosis.

Main Methods:

Treatment of HPV-negative mutTP53 HNSCC cell lines and xenografts with rapalogs.
Assessment of cell viability, colony formation, apoptosis, and autophagy.
Inhibition of autophagy using 3-methyladenine (3-MA) and ULK-101.
Analysis of ULK1, pULK1 S555, and mTORC1 pathway components.
Xenograft studies in nude mice using RAD001 and 3-MA.

Main Results:

Rapalogs significantly reduced HNSCC cell viability and colony formation.
Rapalogs induced autophagy but not apoptosis.
Autophagy inhibition by 3-MA or ULK-101 rescued cell viability, confirming autophagy-dependent cell death (ADCD).
Rapalogs upregulated ULK1 and pULK1 S555 while downregulating mTORC1.
RAD001 treatment in xenografts reduced tumor volume with increased autophagy and ULK1 activation, without inducing apoptosis.

Conclusions:

Rapalogs promote non-apoptotic autophagy-dependent cell death (ADCD) in HPV-negative mutTP53 HNSCC.
The ULK1 pathway is crucial for mediating rapalog-induced ADCD.
Rapalogs demonstrate potential as a therapeutic strategy for HPV-negative mutTP53 HNSCC by inducing ADCD.

Read full analysis

Keywords:

HNSCC TP53 autophagy mTOR rapalog

More Related Videos

Enhancement of Apoptotic and Autophagic Induction by a Novel Synthetic C-1 Analogue of 7-deoxypancratistatin in Human Breast Adenocarcinoma and Neuroblastoma Cells with Tamoxifen

Enhancement of Apoptotic and Autophagic Induction by a Novel Synthetic C-1 Analogue of 7-deoxypancratistatin in Human Breast Adenocarcinoma and Neuroblastoma Cells with Tamoxifen

Published on: May 30, 2012

RNAscope for In situ Detection of Transcriptionally Active Human Papillomavirus in Head and Neck Squamous Cell Carcinoma

RNAscope for In situ Detection of Transcriptionally Active Human Papillomavirus in Head and Neck Squamous Cell Carcinoma

Published on: March 11, 2014

Related Concept Videos

Autophagic Cell Death

Autophagic Cell Death

Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...

The Intrinsic Apoptotic Pathway

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...

Abnormal Proliferation

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the...

Apoptosis

Apoptosis

Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size...

The Extrinsic Apoptotic Pathway

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...

Negative Regulator Molecules

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.

Articles linked to this work by shared authors, journal, and citation graph.

Serum and Tumor PD-L1 Expression and Aggressive Clinicopathologic Features in Papillary Thyroid Carcinoma.

JAMA otolaryngology-- head & neck surgery·2026

mTOR inhibition augments antitumor immune effector response by reprogramming the TP53-mutant, immune-cold HNSCC tumor microenvironment.

Neoplasia (New York, N.Y.)·2026

mTOR inhibition augments antitumor immune effector response by reprogramming the TP53-mutant, immune-cold HNSCC tumor microenvironment.

bioRxiv : the preprint server for biology·2026

Impact of Genetic and Molecular Alterations on Clinical Outcomes in Sinonasal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

International forum of allergy & rhinology·2026

DGAT1 Drives Racially Divergent Fibroblast Activation via ERK1/2-Dependent Tumorigenic Signaling in Prostate Cancer.

Cancer research communications·2026

Breast Cancer Knowledge and Preventive Practice Among Graduate Students: A Scoping Review.

Cancers·2026

See all related articles