Translation stalling induced mitochondrial entrapment of ribosomal quality control related proteins offers cancer cell vulnerability.

Ribosome-associated quality control (RQC) monitors ribosomes for aberrant translation. While the role of RQC in neurodegenerative disease is beginning to be appreciated, its involvement in cancer is understudied. Here, we show a positive correlation between RQC proteins ABCE1 and ZNF598 and high-grade muscle-invasive bladder cancer.

Non-coding RNA and reprogrammed mitochondrial metabolism in genitourinary cancer.

Non-coding ribonucleic acids (ncRNAs) have been recently shown to contribute to tumorigenesis by mediating changes in metabolism. ncRNAs act as key molecules in metabolic pathways regulation. The dysregulation of ncRNAs during cancer progression contributes to altered metabolic phenotypes leading to reprogrammed metabolism.

Non-coding RNA and autophagy: Finding novel ways to improve the diagnostic management of bladder cancer.

Major fraction of the human genome is transcribed in to the RNA but is not translated in to any specific functional protein. These transcribed but not translated RNA molecules are called as non-coding RNA (ncRNA). There are thousands of different non-coding RNAs present inside the cells, each regulating different cellular pathway/pathways.

Regulation of reverse electron transfer at mitochondrial complex I by unconventional Notch action in cancer stem cells.

Metabolic flexibility is a hallmark of many cancers where mitochondrial respiration is critically involved, but the molecular underpinning of mitochondrial control of cancer metabolic reprogramming is poorly understood. Here, we show that reverse electron transfer (RET) through respiratory chain complex I (RC-I) is particularly active in brain cancer stem cells (CSCs). Although RET generates ROS, NAD/NADH ratio turns out to be key in mediating RET effect on CSC proliferation, in part through the NAD-dependent Sirtuin.

PPT1 inhibition enhances the antitumor activity of anti-PD-1 antibody in melanoma.

New strategies are needed to enhance the efficacy of anti-programmed cell death protein antibody (anti-PD-1 Ab) in cancer. Here, we report that inhibiting palmitoyl-protein thioesterase 1 (PPT1), a target of chloroquine derivatives like hydroxychloroquine (HCQ), enhances the antitumor efficacy of anti-PD-1 Ab in melanoma. The combination resulted in tumor growth impairment and improved survival in mouse models.

Autophagy in cancer: Recent advances and future directions.

Autophagy is being explored as a potential therapeutic target for enhancing the cytotoxic effects of chemotherapeutic regimens in various malignancies. Autophagy plays a very important role in cancer pathogenesis. Here, we discuss the updates on the modulation of autophagy via dynamic interactions with different organelles and the exploitation of selective autophagy for exploring therapeutic strategies.

Author Correction: ATF4 couples MYC-dependent translational activity to bioenergetic demands during tumour progression.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

ATF4 couples MYC-dependent translational activity to bioenergetic demands during tumour progression.

The c-Myc oncogene drives malignant progression and induces robust anabolic and proliferative programmes leading to intrinsic stress. The mechanisms enabling adaptation to MYC-induced stress are not fully understood. Here we reveal an essential role for activating transcription factor 4 (ATF4) in survival following MYC activation.

ER Translocation of the MAPK Pathway Drives Therapy Resistance in BRAF-Mutant Melanoma.

Resistance to BRAF and MEK inhibitors (BRAFi + MEKi) in -mutant tumors occurs through heterogeneous mechanisms, including ERK reactivation and autophagy. Little is known about the mechanisms by which ERK reactivation or autophagy is induced by BRAFi + MEKi. Here, we report that in -mutant melanoma cells, BRAFi + MEKi induced SEC61-dependent endoplasmic reticulum (ER) translocation of the MAPK pathway via GRP78 and KSR2.

PPT1 Promotes Tumor Growth and Is the Molecular Target of Chloroquine Derivatives in Cancer.

Clinical trials repurposing lysosomotropic chloroquine (CQ) derivatives as autophagy inhibitors in cancer demonstrate encouraging results, but the underlying mechanism of action remains unknown. Here, we report a novel dimeric CQ (DC661) capable of deacidifying the lysosome and inhibiting autophagy significantly better than hydroxychloroquine (HCQ). Using an photoaffinity pulldown strategy, we identified palmitoyl-protein thioesterase 1 (PPT1) as a molecular target shared across monomeric and dimeric CQ derivatives.

Speckle-type POZ protein as a diagnostic biomarker in renal cell carcinoma.

Background: Renal cell carcinoma (RCC) is the most common kidney neoplasm and requires an early diagnosis because of poor response to conventional cancer treatments. However, till date, there is no reliable tumor marker available for the diagnosis of RCC.

Objective: The aim of the study was to evaluate the expression of speckle-type POZ protein (SPOP) as a biomarker in patients with RCC.

Targeting autophagy in cancer.

Autophagy is a conserved, self-degradation system that is critical for maintaining cellular homeostasis during stress conditions. Dysregulated autophagy has implications in health and disease. Specifically, in cancer, autophagy plays a dichotomous role by inhibiting tumor initiation but supporting tumor progression.

ALDH1A1 and HLTF modulate the activity of lysosomal autophagy inhibitors in cancer cells.

Lysosomal autophagy inhibitors (LAI) such as hydroxychloroquine (HCQ) have significant activity in a subset of cancer cell lines. LAIs are being evaluated in cancer clinical trials, but genetic determinants of sensitivity to LAIs are unknown, making it difficult to predict which tumors would be most susceptible. Here we characterize differentially expressed genes in HCQ-sensitive (-S) and -resistant (-R) cancer cells.

A Unified Approach to Targeting the Lysosome's Degradative and Growth Signaling Roles.

Lysosomes serve dual roles in cancer metabolism, executing catabolic programs (i.e., autophagy and macropinocytosis) while promoting mTORC1-dependent anabolism.

Targeting the unfolded protein response in cancer.

Cancer cells are exposed to various intrinsic and extrinsic factors that disrupt protein homeostasis, producing endoplasmic reticulum (ER) stress. To cope with these situations, cancer cells evoke a highly conserved adaptive mechanism called the unfolded protein response (UPR) to restore the ER homeostasis. Recently, several pharmacological agents have been found to exhibit anti-tumor activity by targeting the UPR components.

Combined Treatment with CCI779 and SB203580 Induces Cellular Senescence in Renal Cell Carcinoma Cell Line via p53 Pathway.

Background: Renal cell carcinoma (RCC) is one of the most common neoplasms that occurs in the kidney and is marked by a unique biology, with a long history of poor response to conventional cancer treatments. In recent years, there have been significant advancements implemented to understanding the biology of RCC, which has led to the introduction of novel targeted therapies in the management of patients with metastatic disease.

Objective: The present study was designed to evaluate the effects of p38 MAPK inhibitor (SB203580), alone and in combination with mTOR inhibitor (CCI779) on apoptosis and cell proliferation.

Functional inhibition of Hsp70 by Pifithrin-μ switches Gambogic acid induced caspase dependent cell death to caspase independent cell death in human bladder cancer cells.

Heat shock protein-70kDa (Hsp70) is a member of molecular chaperone family, involved in the proper folding of various proteins. Hsp70 is important for tumor cell survival and is also reported to be involved in enhancing the drug resistance of various cancer types. Hsp70 controls apoptosis both upstream and downstream of the mitochondria by regulating the mitochondrial membrane permeabilization (MMP) and apoptosome formation respectively.

Gemcitabine and mitomycin induced autophagy regulates cancer stem cell pool in urothelial carcinoma cells.

Urothelial carcinoma (UC) is characterized by therapeutic resistance and frequent tumor relapse. It has been suggested that UC are driven by a rare subset of cancer stem cells (CSCs). In order to understand UC recurrence post therapy, we investigated the behavior of urothelial CSCs after exposure to commonly used chemotherapeutic agents, gemcitabine (GC) and mitomycin (MM).

Caspase-mediated crosstalk between autophagy and apoptosis: Mutual adjustment or matter of dominance.

In the last decade, it has been well established that programmed cell death (PCD) is not confined to apoptosis (type-I PCD) but cells may use different mechanisms of active self-destruction. One such mechanism is autophagy also called as type-II PCD, which is characterized by different morphological and biochemical features. It is not surprising that the demise of a cell either by PCD-I or by PCD-II is a well-controlled and complex process.

Autophagy in Cancer Stem Cells: A Potential Link Between Chemoresistance, Recurrence, and Metastasis.

Cancer cells require an uninterrupted nutritional supply for maintaining their proliferative needs and this high demand in concurrence with inadequate supply of blood and nutrition induces stress in these cells. These cells utilize various strategies like high glycolytic flux, redox signaling, and modulation of autophagy to avoid cell death and overcome nutritional deficiency. Autophagy allows the cell to generate ATP and other essential biochemical building blocks necessary under such adverse conditions.

Autophagy inhibition suppresses the tumorigenic potential of cancer stem cell enriched side population in bladder cancer.

The mechanisms that underlie tumor formation and progression have not been elucidated in detail in cancer biology. Recently, the identification of a tumor cell subset defined as cancer stem cells (CSCs), which is enriched for tumor initiating capacity, has engendered new perspectives towards selective targeting of tumors. In this study, we isolated the side population (SP) cells which share characteristics of CSCs from bladder cancer cell lines, T24 and UM-UC-3 by fluorescence activated cell sorting.

Inhibition of grade dependent autophagy in urothelial carcinoma increases cell death under nutritional limiting condition and potentiates the cytotoxicity of chemotherapeutic agent.

Purpose: We evaluated the status of autophagy in different grades of urothelial carcinoma and explored autophagy modulators as a potential adjunctive therapeutic agent for urothelial carcinoma.

Materials And Methods: The study was performed in tumor tissue from patients with low and high grade urothelial carcinoma, in normal urothelial tissue and in the T24 cell line. Autophagic vesicles and the expression of various autophagic proteins were studied in tissue samples by transmission electron microscopy and Western blot, respectively.