Persistent disparities of cervical cancer among American Indians/Alaska natives: Are we maximizing prevention tools?

BACKGROUND: Cervical cancer incidence and mortality disparities experienced by American Indian/Alaska Native (AI/AN) women have persisted for decades. Pap smear screening and HPV vaccination are powerful tools to prevent cervical cancer. We evaluated the utilization of these tools among AI/ANs living in the Pacific Northwest (PNW). METHODS: The Indian Health Service (IHS) National Data Warehouse's Epi Data Mart was analyzed using all healthcare visits from 2010 to 2020 from IHS, Tribal, and Urban Indian clinics in the PNW. Women ages 21-64 were included and considered up-to-date on pap smears if they had either cytology within 3 years or cytology with HPV testing within 5 years of the most recent clinical encounter. HPV vaccination rates for both sexes were calculated for individuals ages 9-26. HPV vaccination was considered complete if: two vaccines were received prior to age 15 or after three vaccinations if initiated after age 15. FINDINGS: Cervical cancer screening rates are below the national average of 73.5% ranging between 57.1% - 65.0%. Sub-analysis of age groups shows substantially lower rates of up-to-date pap smear screening in the 50-64 age group. HPV vaccination rates have increased over time for both sexes across all age groups. However, the current vaccination rate of 58.6% is well below the Healthy People 2030 goal of 84.3%. INTERPRETATION: Cervical cancer screening and HPV vaccination are the cornerstones of cervical cancer prevention and early detection. These tools are underutilized and public health efforts can be strengthened to improve cervical cancer disparities in AI/AN women. FUNDING: Author ASB: Funding for this project has been provided through the Robert Wood Johnson Foundation Harold Amos Minority Faculty Development Grant and the National Cancer Institute K08 Mentored Clinical Scientist Development Award.

Pathological glycogenesis through glycogen synthase 1 and suppression of excessive AMP kinase activity in myeloid leukemia cells.

The rapid proliferation of myeloid leukemia cells is highly dependent on increased glucose metabolism. Through an unbiased metabolomics analysis of leukemia cells, we found that the glycogenic precursor UDP-D-glucose is pervasively upregulated, despite low glycogen levels. Targeting the rate-limiting glycogen synthase 1 (GYS1) not only decreased glycolytic flux but also increased activation of the glycogen-responsive AMP kinase (AMPK), leading to significant growth suppression. Further, genetic and pharmacological hyper-activation of AMPK was sufficient to induce the changes observed with GYS1 targeting. Cancer genomics data also indicate that elevated levels of the glycogenic enzymes GYS1/2 or GBE1 (glycogen branching enzyme 1) are associated with poor survival in AML. These results suggest a novel mechanism whereby leukemic cells sustain aberrant proliferation by suppressing excess AMPK activity through elevated glycogenic flux and provide a therapeutic entry point for targeting leukemia cell metabolism.

Capturing the herpes simplex virus core fusion complex (gB-gH/gL) in an acidic environment.

Herpes simplex virus (HSV) entry requires the core fusion machinery of gH/gL and gB as well as gD and a gD receptor. When gD binds receptor, it undergoes conformational changes that presumably activate gH/gL, which then activates gB to carry out fusion. gB is a class III viral fusion protein, while gH/gL does not resemble any known viral fusion protein. One hallmark of fusion proteins is their ability to bind lipid membranes. We previously used a liposome coflotation assay to show that truncated soluble gB, but not gH/gL or gD, can associate with liposomes at neutral pH. Here, we show that gH/gL cofloats with liposomes but only when it is incubated with gB at pH 5. When gB mutants with single amino acid changes in the fusion loops (known to inhibit the binding of soluble gB to liposomes) were mixed with gH/gL and liposomes at pH 5, gH/gL failed to cofloat with liposomes. These data suggest that gH/gL does not directly associate with liposomes but instead binds to gB, which then binds to liposomes via its fusion loops. Using monoclonal antibodies, we found that many gH and gL epitopes were altered by low pH, whereas the effect on gB epitopes was more limited. Our liposome data support the concept that low pH triggers conformational changes to both proteins that allow gH/gL to physically interact with gB.

Crystal structure of the conserved herpesvirus fusion regulator complex gH-gL.

Herpesviruses, which cause many incurable diseases, infect cells by fusing viral and cellular membranes. Whereas most other enveloped viruses use a single viral catalyst called a fusogen, herpesviruses, inexplicably, require two conserved fusion-machinery components, gB and the heterodimer gH-gL, plus other nonconserved components. gB is a class III viral fusogen, but unlike other members of its class, it does not function alone. We determined the crystal structure of the gH ectodomain bound to gL from herpes simplex virus 2. gH-gL is an unusually tight complex with a unique architecture that, unexpectedly, does not resemble any known viral fusogen. Instead, we propose that gH-gL activates gB for fusion, possibly through direct binding. Formation of a gB-gH-gL complex is critical for fusion and is inhibited by a neutralizing antibody, making the gB-gH-gL interface a promising antiviral target.