Recent progress in understanding the importance and origins of lipid rafts in microbial cell membranes has focused attention on membranes containing branched-chain fatty acids. The working hypothesis is that branched fatty acids increase the fluidity of the bilayer, analogous to unsaturated fatty acids in membranes of higher organisms. Here, we perform a series of 7 μs long atomistic simulations on biomimetic, branched-chain lipid containing bilayer patches, systematically varying the amount of the straight-chain fatty acid component, n16:0, from 7.0 to 47.3 mol %. The simulations reveal thickening and ordering of the bilayer as well as higher bilayer viscosity and bending modulus with increasing n16:0 content, thus providing quantitative support that branched fatty acids increase the bilayer fluidity. A sharp transition in these properties is observed at ∼20% n16:0 content, resembling a phase change. The simulations provide the first access to ordered and disordered phases in a bacterial cell membrane mimic containing branched-chain lipids. Granted several assumptions, a comparison of these phases provides estimates of physical properties such as hydrophobic mismatch (∼1.2 Å), difference in bending moduli (∼15.7 k B T), and the line tension (∼0.6 pN) for a putative lipid raft in the cell membrane of an organism such as Bacillus subtilis or Staphylococcus aureus.

BackgroundAdvanced penile squamous cell carcinoma (pSCC) is a rare and aggressive malignancy with limited success of immune‐checkpoint inhibitors (ICIs). Approximately half of pSCC cases are associated with human papillomavirus (HPV) infection.MethodsEvaluation was done retrospectively of the landscape of somatic alterations and ICI‐related biomarkers in pSCC by using the Caris Life Sciences data set with the aim to establish signatures for HPV‐dependent oncogenesis. The pSCC tumors were analyzed by using next‐generation sequencing (NGS) of DNA and RNA. Programmed death ligand 1 (PD‐L1) expression was evaluated by immunohistochemistry (IHC). Microsatellite instability (MSI) was tested by fragment analysis, IHC (SP142; ≥1%), and NGS. Tumor mutational burden (TMB)–high was defined as ≥10 mutations/Mb. HPV16/18 status was determined by using whole‐exome sequencing (WES) when available. Significance was adjusted for multiple comparisons (q value < .05).ResultsNGS of the overall cohort (N = 108) revealed TP53 (46%), CDKN2A (26%), and PIK3CA (25%) to be the most common mutations. Overall, 51% of tumors were PD‐L1+, 10.7% had high TMB, and 1.1% had mismatch repair–deficient (dMMR)/MSI‐high status. Twenty‐nine patients had their HPV status made available by WES (HPV16/18+, n = 13; HPV16/18−, n = 16). KMT2C mutations (33% vs. 0%) and FGF3 amplifications (30.8% vs. 0%) were specific to HPV16/18+ tumors, whereas CDKN2A mutations (0% vs. 37.5%) were exclusive to HPV16/18− tumors. TMB‐high was exclusively found in the HPV16/18+ group (30.8%). The two groups had comparable PD‐L1 and dMMR/MSI‐H status.ConclusionsIn a large and comprehensive NGS‐based evaluation of somatic alterations in pSCC, HPV16/18+ versus HPV16/18− pSCCs were molecularly distinct tumors. Our finding that TMB‐high is exclusive to HPV16/18+ tumors requires confirmation in larger data sets.Plain Language Summary Penile squamous cell carcinoma (pSCC) is a rare and aggressive malignancy in the advanced setting, with poor prognosis and little success with immune‐checkpoint inhibitors (ICIs) in an unselected patient approach. Human papillomavirus (HPV) infection is a known risk factor for pSCC; its impact on genomic tumor profiling is less defined. Using next‐generation sequencing, we explored the genetic landscape and ICI‐related biomarkers of pSCC and HPV‐driven oncogenic molecular signatures. Our results indicate that HPV‐positive and HPV‐negative pSCCs are molecularly distinct tumors. Increased tumor mutational burden is associated with HPV‐positive tumors, and could serve as a biomarker for predicting therapeutic response to ICI‐based therapies. Our results support the growing literature indicating that HPV status in pSCC can be used to guide patient stratification in ICI‐based clinical trials.

Immune-oncologic (IO) therapy has revolutionized the treatment and management of oncologic disease. Immunotherapy functions by enhancing the host immune-systems ability to endogenously clear malignant cells, however, this activation can also lead to immune-mediated damage to healthy native tissues. These side effects are known as immune-related adverse events or irAEs and can even present with phenotypes similar to autoimmune diseases. IrAEs are the major consequence of checkpoint inhibitors and can have a significant impact on a patient’s cancer treatment and long-term quality of life. The management of these irAEs follows a similar approach to autoimmune diseases. More specifically, the management is akin to that of autoimmune disease exacerbations. While there is an array of immune-suppressing agents that can be used, steroids, immunomodulators and IO discontinuation are cornerstones of irAE management. The exact approach and dosing are based on the severity and subtype of irAE presented. Within recent years, there has been a push to better prevent and manage irAEs when they arise. There has been an additional effort to increase the number of steroid-sparing agents available for irAE treatment given the consequences of long-term steroid therapy as well as patient contraindications to steroids. The goals of this review are to summarize irAE management, highlight significant advances made in recent years and emphasize the future directions that will optimize the use of IO therapy in oncology.

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Thermostable α-amylases are widely used in industry. The α-amylase from Bacillus licheniformis (BLA) with six potential glycosylation sites possessed excellent thermal and pH stability and high activity. Here, it was expressed in Pichia pastoris. The Pic-BLA-producing yeast without any antibiotics-resistant gene was cultivated in flasks and the amylase activity in fermentation supernatant reached 900 U/mL. The recombinant α-amylase Pic-BLA produced in P. pastoris was deeply glycosylated with 30% increase in molecular mass (MM). The deglycosylation treatment by Endoglycosidase H (Endo H) reduced the MM of Pic-BLA. Thermostability analysis showed that Pic-BLA and deglycosylated Pic-BLA were similar in heat tolerance. In order to eliminate the extra impact of Endo H, the BLA was also expressed in Escherichia coli to get non-glycosylated Eco-BLA. A comparative study between non-glycosylated Eco-BLA and glycosylated Pic-BLA showed no obvious difference in thermostability. It is speculated that the glycosylation has little effect on the thermostability of α-amylase BLA.