Malignant cells often demonstrate a proliferative advantage when compared to non-malignant cells. However, the rapid growth and metabolism required for survival can also highlight vulnerabilities specific to these malignant cells. One such vulnerability exhibited by cancer is an increased demand for amino acids (AAs), which often results in a dependency on exogenous sources of AAs or requires upregulation of de novo synthesis. These metabolic alterations can be exploited by therapy, which aims to improve treatment outcome and decrease relapse and reoccurrence. One clinically utilised strategy targeting AA dependency is the use of asparaginase in the treatment of acute lymphoblastic leukaemia (ALL), which results in a depletion of exogenous asparagine and subsequent cancer cell death. Examples of other successful strategies include the exploitation of arginine deiminase and methioninase, nutrient restriction of methionine and the inhibition of glutaminase. In this review, we summarise these treatment strategies into three promising avenues: AA restriction, enzymatic depletion and inhibition of metabolism. This review provides an insight into the complexity of metabolism in cancer, whilst highlighting these three current research avenues that have support in both preclinical and clinical settings.
The adeno-associated virus (AAV) non-structural Rep proteins catalyze all the DNA transactions required for virus viability including, DNA replication, transcription regulation, genome packaging, and during the latent phase, site-specific integration. Rep proteins contain two multifunctional domains: an Origin Binding Domain (OBD) and a SF3 helicase domain (HD). Studies have shown that Rep proteins have a dynamic oligomeric behavior where the nature of the DNA substrate molecule modulates its oligomeric state. In the presence of ssDNA, Rep68 forms a large double-octameric ring complex. To understand the mechanisms underlying AAV Rep function, we investigated the cryo-EM and X-ray structures of Rep68–ssDNA complexes. Surprisingly, Rep68 generates hybrid ring structures where the OBD forms octameric rings while the HD forms heptamers. Moreover, the binding to ATPγS promotes a large conformational change in the entire AAA+ domain that leads the HD to form both heptamer and hexamers. The HD oligomerization is driven by an interdomain linker region that acts as a latch to ‘catch’ the neighboring HD subunit and is flexible enough to permit the formation of different stoichiometric ring structures. Overall, our studies show the structural basis of AAV Rep's structural flexibility required to fulfill its multifunctional role during the AAV life cycle.
Diabetes and cancer are two heterogenous diseases which are rapidly increasing in prevalence globally. A link between these two non-communicable diseases was first identified over 100 years ago however, recent epidemiological studies and advances in genomic research have provided greater insight into the association between diabetes and cancer. Epidemiological studies have suggested that individuals with diabetes have an increased risk of several types of cancer (including liver, pancreas, colorectal, breast and endometrial) and an increased risk of cancer mortality. However, this increased risk is not observed in all cancers, for example, there is a reduced risk of prostate cancer in individuals with diabetes. It has also been observed that cancer patients have an increased risk of developing diabetes, highlighting that the relationship between these diseases is not straightforward. Evidence of a shared genetic aetiology along with numerous lifestyle and clinical factors have made it challenging to establish if the relationship between the two diseases is causal or a result of confounding factors. This review takes a pan-cancer approach to highlight the complexities of the interactions between type 2 diabetes (T2D) and cancer development indicating where advances in genomic research have enabled a greater insight into these two diseases.
The adeno-associated virus (AAV) Rep proteins use a unique AAA + domain to catalyze DNA replication, transcription regulation, and genome packaging. Also, they mediate sitespecific integration during a latent phase. To understand the mechanisms underlying AAV Rep function, we investigated the cryo-EM and X-ray structures of Rep68-ssDNA complexes. Surprisingly, Rep68 generates hybrid ring structures where the Origin-Binding-Domain (OBD) forms octameric rings while the helicase domain (HD) forms heptamers. Moreover, the binding to ATPgS promotes a large conformational change in the entire AAA + domain that leads the HD to form both heptamer and hexamers. The HD oligomerization is driven by an interdomain linker region that acts as a latch to 'catch' the neighboring HD subunit and is flexible enough to permit the formation of different stoichiometric ring structures. Overall, our studies show the structural basis of AAV Rep's structural flexibility required to fulfill its multifunctional role during the AAV life cycle. We would like to thank Ed Eng, Venkata Dandey, Elina Kopylov and outstanding staff from the National Center for Cryo-EM access and Training (NCCAT). We would like to acknowledge Lauren Hales Beck, Nancy Meyer from the Pacific Northwest Cryo-EM Center (PNCC) supported by NIH grant U24GM129547. Declaration of interest.Els Henckaerts has a sponsored research agreement with Handl Therapeutics. Data availabilityAll cryo-EM densities and atomic coordinates have been deposited to EMDB. Densities for the DOC apo and ATPgS-bound structures are EMD-XXXX and EMD-XXXX respectively. Rep68-ssAAVS1-ATPgS density is EMD-XXX and PDB: XXXX. Rep68-ssdT25 hexamer density is EMD-XXX and PDB:XXXX. Xray structure coordinates for AAV2 OBD-ssRBS complex is PDB:XXXX.
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