HER3 V104 mutations regulate cell signaling, growth, and drug sensitivity in cancer.

HER3 is mutated in ~2%-10% of cancers depending on the cancer type. We found the HER3-V104L mutation to be activating from patient-derived mutations introduced via lentiviral transduction in HER3KO HER2 + HCC1569 breast cancer cells in which endogenous HER3 was eliminated by CRISPR/Cas9. Cells expressing HER3-V104L showed higher p-HER3 and p-ERK1/2 expression versus cells expressing wild-type HER3 or HER3-V104M. Patients whose tumor expressed the HER3 V104L variant had a reduced probability of overall survival compared to patients lacking a HER3 mutation whereas we did not find a statistically significant difference in overall survival of various cancer patients with the HER3 V104M mutation. Our data showed that HER2 inhibitors suppressed cell growth of HCC1569HER3KO cells stably expressing the HER3-V104L mutation. Cancer cell lines (SNU407, UC15 and DV90) with endogenous HER3-V104M mutation showed reduced cell proliferation and p-HER2/p-ERK1/2 expression with HER2 inhibitor treatment. Knock down of HER3 abrogated cell proliferation in the above cell lines which were overall more sensitive to the ERK inhibitor SCH779284 versus PI3K inhibitors. HER3-V104L mutation stabilized HER3 protein expression in COS7 and SNUC5 cells. COS7 cells transiently transfected with the HER3-V104L mutation in the presence of HER binding partners showed higher expression of p-HER3, p-ERK1/2 versus HER3-WT in a NRG-independent manner without any change in AKT signaling. Overall, this study shows the clinical relevance of the HER3 V104L and the V104M mutations and its response to HER2, PI3K and ERK inhibitors.

Metabolic complications in lung transplantation for cystic fibrosis - A case control study.

Background: Metabolic complications post-lung transplant are poorly understood and little is known about how these complications differ between patients with or without cystic fibrosis (pwCF and pwoCF). This study compared post-lung transplant outcomes between pwCF and pwoCF relating to survival and incidence of diabetes, dyslipidaemia, hypertension, and renal impairment. Methods: A retrospective (2004-2017) case-control study involving 90 pwCF and 90 pwoCF (age, sex and year of transplant matched) was conducted. Demographic variables, pre/post-transplant metabolic diseases, blood investigations and medications were extracted. Descriptive statistics were used to describe the cohort. Mann-Whitney U and Chi-squared tests were used to analyse morbidity and mortality data. Regression analyses were used to identity independent variables that impacted clinical outcomes. Kaplan Meier analysis with log-rank testing was used to compare survival. Results: PwCF were younger, had lower BMIs, and were less likely to have pre-transplant extracorporeal membrane oxygenation (ECMO) use. A total of 37 pwCF and 41 pwoCF died (p = 0.65) during the period of observation with no differences in survival. Adjusting for covariates of age, sex and BMI via multiple logistic regression, CF status was associated with a dramatic increased risk of new-onset diabetes post-transplant (adjusted odds ratio 28.7; 95 % CI, 28.76 to 108.7). No other differences in adjusted risk were found. Conclusions: As pwCF had a greater adjusted risk of developing new post-transplant diabetes and experienced metabolic complications at similar rates as pwoCF, the findings highlight the need for rigorous monitoring of pwCF for possible metabolic complications post-transplant.

Acquired Secondary HER2 Mutations Enhance HER2/MAPK Signaling and Promote Resistance to HER2 Kinase Inhibition in Breast Cancer.

HER2 mutations drive the growth of a subset of breast cancers and are targeted with HER2 tyrosine kinase inhibitors (TKI) such as neratinib. However, acquired resistance is common and limits the durability of clinical responses. Most HER2-mutant breast cancers progressing on neratinib-based therapy acquire secondary mutations in HER2. It is unknown whether these secondary HER2 mutations, other than the HER2T798I gatekeeper mutation, are causal to neratinib resistance. Herein, we show that secondary acquired HER2T862A and HER2L755S mutations promote resistance to HER2 TKIs via enhanced HER2 activation and impaired neratinib binding. While cells expressing each acquired HER2 mutation alone were sensitive to neratinib, expression of acquired double mutations enhanced HER2 signaling and reduced neratinib sensitivity. Computational structural modeling suggested that secondary HER2 mutations stabilize the HER2 active state and reduce neratinib binding affinity. Cells expressing double HER2 mutations exhibited resistance to most HER2 TKIs but retained sensitivity to mobocertinib and poziotinib. Double-mutant cells showed enhanced MEK/ERK signaling, which was blocked by combined inhibition of HER2 and MEK. Together, these findings reveal the driver function of secondary HER2 mutations in resistance to HER2 inhibition and provide a potential treatment strategy to overcome acquired resistance to HER2 TKIs in HER2-mutant breast cancer. SIGNIFICANCE: HER2-mutant breast cancers acquire secondary HER2 mutations that drive resistance to HER2 tyrosine kinase inhibitors, which can be overcome by combined inhibition of HER2 and MEK.

HER2 inhibition increases non-muscle myosin IIA to promote tumorigenesis in HER2+ breast cancers.

HER2 is over-expressed in around 15% to 20% of breast cancers. HER3 plays a critical role in HER2 mediated tumorigenesis. Increased HER3 transcription and protein levels occur upon inhibition of HER2. We aimed to identify proteins that bound to HER3 upon inhibition of the HER family with the pan-HER inhibitor neratinib in HER2+ breast cancer cells. Immunoprecipitation of HER3 followed by mass spectrometry experiments found non-muscle myosin IIA (NMIIA) increased upon neratinib treatment relative to vehicle DMSO treatment. MYH9 is the gene that encodes for the heavy chain of NMIIA. Breast cancer patients with high MYH9 were significantly associated with a shorter disease specific survival compared to patients with low MYH9 expression from the METABRIC cohort of patients. In addition, high MYH9 expression was associated with HER2+ tumors from this cohort. Immunoblots of whole cell lysates of BT474 and MDA-MB-453 HER2+ breast cancer cells demonstrated elevated HER3 and NMIIA protein levels upon neratinib treatment for 24 hours. To examine the role of NMIIA in HER2+ breast cancer, we modulated NMIIA levels in BT474 and MDA-MB-453 cells using doxycycline inducible shRNA targeting MYH9. MYH9 knockdown reduces HER3 protein levels and concomitant reduction in downstream P-Akt. In addition, loss of MYH9 suppresses cell growth, proliferation, migration, and invasion. Our data reveals that NMIIA regulates HER3 and loss of NMIIA reduces HER2+ breast cancer growth.

RIDR-PI-103, ROS-activated prodrug PI3K inhibitor inhibits cell growth and impairs the PI3K/Akt pathway in BRAF and MEK inhibitor-resistant BRAF-mutant melanoma cells.

Reactive oxygen species (ROS) levels are elevated after acquisition of resistance to v-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors including dabrafenib and MEK inhibitors such as trametinib in BRAF-mutant melanoma. To circumvent toxicity to PI-103 (a pan PI3K inhibitor), we utilized a novel ROS-induced drug release (RIDR)-PI-103, with a self-cyclizing moiety linked to PI-103. Under high ROS conditions, RIDR-PI-103 releases PI-103, which inhibits conversion of phosphatidylinositol 4,5-bisphosphate (PIP 2 ) to phosphatidylinositol 3,4,5-triphosphate (PIP 3 ). Previous findings demonstrate that trametinib and dabrafenib-resistant (TDR) cells maintain p-Akt levels compared to parental counterparts and have significantly higher ROS. This is a rationale to explore the efficacy RIDR-PI-103 in TDR cells. We tested the effect of RIDR-PI-103 on melanocytes and TDR cells. RIDR-PI-103 exhibited less toxicity compared to PI-103 at 5 µM in melanocytes. RIDR-PI-103 significantly inhibited TDR cell proliferation at 5 and 10 µM. Twenty-four hour treatment with RIDR-PI-103 inhibited p-Akt, p-S6 (Ser240/244) and p-S6 (Ser235/236). We assessed the mechanism of activation of RIDR-PI-103, using glutathione or t-butyl hydrogen peroxide (TBHP) on the TDR cells in the presence or absence of RIDR-PI-103. Addition of the ROS scavenger glutathione to RIDR-PI-103 significantly rescued the cell proliferation in TDR cell lines while addition of the ROS inducer TBHP and RIDR-PI-103 inhibited cell proliferation in WM115 and WM983B TDR cell lines. Examining the efficacy of RIDR-PI-103 on BRAF and MEK inhibitor-resistant cells will expand possible treatment options and open avenues for the development of new ROS-based treatment therapies for BRAF-mutant melanoma patients.

HER3 Alterations in Cancer and Potential Clinical Implications.

In recent years, the third member of the HER family, kinase impaired HER3, has become a target of interest in cancer as there is accumulating evidence that HER3 plays a role in tumor growth and progression. This review focuses on HER3 activation in bladder, breast, colorectal, and lung cancer disease progression. HER3 mutations occur at a rate up to ~10% of tumors dependent on the tumor type. With patient tumors routinely sequenced for gene alterations in recent years, we have focused on HER3 mutations in bladder, breast, colon, and lung cancers particularly in response to targeted therapies and the potential to become a resistance mechanism. There are currently several HER3 targeting drugs in the pipeline, possibly improving outcomes for cancer patients with tumors containing HER3 activation and/or alterations.

Feasibility and Acceptability of Virtual Implementation of a Sexual Reproductive Health Teen Pregnancy Prevention Program for Native Youth.

American Indian/Alaska Native (Native) youth face high rates of substance use, teen pregnancy and sexually transmitted infections. In response to the COVID-19 pandemic, Respecting the Circle of Life (RCL), a sexual reproductive health and teen pregnancy prevention program for Native youth and their trusted adult, was adapted and delivered in a virtual format with Native youth in a rural, reservation-based Native community. This manuscript describes the adaptation process, feasibility, and acceptability of virtual program implementation. The manuscript describes the process of rapidly shifting the RCL program into a virtual format. In addition, a mixed-methods process evaluation of implementation forms, program feedback forms, in-depth interviews with participants, and staff debriefing sessions was completed. Results show virtual implementation of RCL is both feasible and acceptable for Native youth and their trusted adults. A key benefit of virtual implementation is the flexibility in scheduling and ability to have smaller groups of youth, which offers greater privacy for youth participants compared to in-person implementation with larger groups. However, internet connectivity did present a challenge for virtual implementation. Ultimately, sexual and reproductive health programs seeking to reach Native youth and families should consider virtual implementation methods, both during and outside of pandemic situations.

Improving communication between American Indian youth and caregivers to prevent teenage pregnancy.

American Indian (AI) youth are at increased risk for poor reproductive health outcomes. Parental communication and monitoring are established predictors of sexual risk-taking among adolescents. No program evaluations of sexual risk avoidance programs have focused exclusively on AI youth and parents. This study assesses the impact of the Respecting the Circle of Life (RCL) Teenage Pregnancy Prevention program on parent-youth communication and parental monitoring through a randomized controlled trial with AI youth ages 11-19 and their trusted adults (parents/caregivers) (N = 518). RCL consists of 8-peer group and one parent-youth session. Trusted adult participants completed the Parental Monitoring Scale and the Parent Adolescent Communication Scale at baseline and 3 and 9 months post-intervention via self-report. Intervention impact was evaluated using linear regression models, which included an indicator for study group. At 3 months post, trusted adults in the intervention reported significantly higher levels of sexual health communication (P = 0.042) and spoke to their child more often about how to get condoms (P = 0.001), get birth control (P = 0.014) and protect themselves from human immunodeficiency virus (P = 0.005) compared with trusted adults in the control condition. Program impact varied by age and sex. This study adds to literature and extends findings on RCL impact.

The impact of biosimilar insulins on the diabetes landscape.

The cost of diabetes care in the United States continues to rise, with insulin costs growing rapidly. Accessibility and affordability of these life-saving medications are concerns for providers and patients that need to be addressed. Availability of biosimilar insulin products may help address these issues by introducing additional competition to the insulin market, but they may also face adoption challenges from patients and health care providers alike. In addition, policymakers at state and federal levels are examining and addressing rising insulin costs through legislative and administrative actions. The purpose of this paper is to review the current US diabetes landscape, highlight the differences between biosimilar insulins and follow-on insulins and considerations for successful adoption of biosimilar insulins, and review the current policy landscape regarding rising insulin costs. DISCLOSURES: This Viewpoints article was supported by Sandoz, Inc. Wagner and Patel are employees of Sandoz, Inc. White was employed by Sandoz, Inc., at the time of this study.

Empowering our people: Predictors of retention in an STI risk reduction program among rural Native Americans with binge substance use.

PURPOSE: Substance use and sexual risk-taking have been shown to co-occur. Programs focused on sexually transmitted infections (STIs) reduction may benefit substance-using, particularly binge substance-using, adults. This is especially true for rural Native American communities who endure sexual and substance use disparities and have few STI risk reduction programs. This study explores factors predicting retention in an STI risk reduction program among rural Native adults engaged in binge substance use. METHODS: We analyzed data from 150 Native adults ages 18-55 participating in an evaluation of "EMPWR," a 2-session STI risk reduction program in a rural, reservation-based community. Multivariate logistic regression models were used to estimate associations between independent variables and program completion across demographics, sexual behaviors, substance use behaviors, mental health, recent health care utilization, and perceived enculturation and discrimination. FINDINGS: The sample was 49.2% (n = 59) female with a mean age of 33.61 years (SD = 8.25). Twenty-six completed only the first EMPWR session, 94 completed both EMPWR sessions, and 30 were randomized but completed 0 sessions. Being married/cohabiting (adjusted odds ratio [AOR] = 6.40, P = .0063) and living with an older generation (AOR = 4.86, P = .0058) were significantly associated with higher odds of completing EMPWR. CONCLUSIONS: Findings provide insight on factors driving retention of Natives with recent binge substance use in STI risk reduction programming. An important contribution to Native health literature is that living with an older generation positively predicted EMPWR program completion, suggesting that STI risk reduction programs should harness the strength of families to ensure program attendance and optimize impacts in rural reservation contexts.

IGF1R/IR Mediates Resistance to BRAF and MEK Inhibitors in BRAF-Mutant Melanoma.

The use of BRAF and MEK inhibitors for patients with BRAF-mutant melanoma is limited as patients relapse on treatment as quickly as 6 months due to acquired resistance. We generated trametinib and dabrafenib resistant melanoma (TDR) cell lines to the MEK and BRAF inhibitors, respectively. TDR cells exhibited increased viability and maintenance of downstream p-ERK and p-Akt as compared to parental cells. Receptor tyrosine kinase arrays revealed an increase in p-IGF1R and p-IR in the drug resistant cells versus drug sensitive cells. RNA-sequencing analysis identified IGF1R and INSR upregulated in resistant cell lines compared to parental cells. Analysis of TCGA PanCancer Atlas (skin cutaneous melanoma) showed that patients with a BRAF mutation and high levels of IGF1R and INSR had a worse overall survival. BMS-754807, an IGF1R/IR inhibitor, suppressed cell proliferation along with inhibition of intracellular p-Akt in TDR cells. Dual inhibition of IGF1R and INSR using siRNA reduced cell proliferation. The combination of dabrafenib, trametinib, and BMS-754807 treatment reduced in vivo xenograft tumor growth. Examining the role of IGF1R and IR in mediating resistance to BRAF and MEK inhibitors will expand possible treatment options to aid in long-term success for BRAF-mutant melanoma patients.

Prevention of Sexually Transmitted Diseases and Pregnancy Prevention Among Native American Youths: A Randomized Controlled Trial, 2016-2018.

Objectives. To evaluate the efficacy of the Respecting the Circle of Life program (RCL) among Native American youths 11 to 19 years of age residing in a rural reservation community in the southwestern United States. Methods. Between 2016 and 2018, we conducted a randomized controlled trial of the RCL program with 534 Native youths. Participants completed assessments at baseline and 9 and 12 months after the intervention. We conducted intention-to-treat analyses based on study group randomization. Results. At 9 months, intervention participants had significantly better condom use self-efficacy (P < .001), higher intentions to use condoms (P = .024) and abstain from sex (P = .008), and better contraceptive use self-efficacy (P < .001) than control participants, as well as better condom use (P = .032) and contraceptive use (P = .002) negotiation skills. At 12 months, intervention participants had significantly better sexual and reproductive health knowledge (P = .021), condom use self-efficacy (P < .001), contraceptive use self-efficacy (P < .001), and contraceptive use negotiation skills (P = .004) than control participants. Intervention participants reported significantly more communication with their parents about sexual and reproductive health than control participants at both 9 and 12 months (P = .042 and P = .001, respectively). Conclusions. The RCL program has a significant impact on key factors associated with pregnancy prevention among Native youths and should be used as an adolescent pregnancy prevention strategy. Trial Registration.  Clinical Trials.gov identifier: NCT02904629. (Am J Public Health. 2021;111(10): 1874-1884. https://doi.org/10.2105/AJPH.2021.306447).

Diné (Navajo) female perspectives on mother-daughter communication and cultural assets around the transition to womanhood: a cross-sectional survey.

BACKGROUND: The inclusion of protective factors ("assets") are increasingly supported in developing culturally grounded interventions for American Indian (AI) populations. This study sought to explore AI women's cultural assets, perspectives, and teachings to inform the development of a culturally grounded, intergenerational intervention to prevent substance abuse and teenage pregnancy among AI females. METHODS: Adult self-identified AI women (N = 201) who reside on the Navajo Nation completed a cross-sectional survey between May and October 2018. The 21-question survey explored health communication around the transition to womanhood, cultural assets, perceptions of mother-daughter reproductive health communication, and intervention health topics. Univariate descriptive analyses, chi squared, and fisher's exact tests were conducted. RESULTS: Respondents ranged in age from 18 to 82 years, with a mean age of 44 ± 15.5 years. Women self-identified as mothers (95; 48%), aunts (59; 30%), older sisters (55; 28%), grandmothers (37; 19%), and/or all of the aforementioned (50; 25%). 66% (N = 95) of women admired their mother/grandmother most during puberty; 29% (N = 58) of women were 10-11 years old when someone first spoke to them about menarche; and 86% (N=172) felt their culture was a source of strength. 70% (N = 139) would have liked to learn more about reproductive health when they were a teenager; 67% (N = 134) felt Diné mothers are able to provide reproductive health education; 51% (N = 101) reported having a rite of passage event, with younger women desiring an event significantly more than older women. Responses also indicate a disruption of cultural practices due to government assimilation policies, as well as the support of male relatives during puberty. CONCLUSIONS: Results informed intervention content and delivery, including target age group, expanded caregiver eligibility criteria, lesson delivery structure and format, and protective cultural teachings. Other implications include the development of a complementary fatherhood and/or family-based intervention to prevent Native girls' substance use and teen pregnancy.

Impacts of the respecting the circle of life teen pregnancy prevention program on risk and protective factors for early substance use among native American youth.

BACKGROUND: Early substance use disproportionately impacts Native American (Native) youth and increases their risk for future abuse and dependence. The literature urges for interventions to move beyond focusing on single risk behaviors (e.g. substance use) and instead have capacity to improve health risk behaviors co-occuring during adolescence, particularly among Native populations for whom few evidence-based interventions (EBI) exist. We evaluated the effectiveness of the Respecting the Circle of Life program (RCL) on risk and protective factors for early substance use. RCL is a culturally tailored EBI shown to improve sexual health outcomes among Native youth. METHODS: We conducted secondary analyses of data collected through a community-based randomized controlled trial of RCL evaluated among Native youth (ages 11-19) residing on a rural reservation between 2015-2020 (N = 534, 47.4 % male). We used linear regression, controlling for baseline age and sex, to test between study group differences in outcomes at 3-, 9-, and 12-month post-intervention. Models were stratified by sex and age (11-12, 13-14, and 15+ years of age) to examine differences within these subgroups. RESULTS: Youth receiving RCL reported lower intention to use substances through 12-months follow-up (p = 0.006). Statistically significant improvements were also observed across peer, parent, and sexual partner risk and protective factors to delay substance use initiation, with notable differences among boys and participants ages 13-14. CONCLUSIONS: RCL is a primary prevention, skills-based program effective in preventing risks for substance use. This evaluation underscores the value in developing programs that influence concurrent adolescent risk behaviors, especially for Native communities who endure multiple health disparities.

Rigorous evaluation of a substance use and teen pregnancy prevention program for American Indian girls and their female caregivers: a study protocol for a randomized controlled trial.

BACKGROUND: Early sexual initiation is associated with higher risk for sexually transmitted infection, teen pregnancy, domestic violence and substance use in later adolescence and early adulthood. Native American adolescents are more likely to have early sexual initiation compared to other racial/ethnic groups. Few programs designed with and for Native adolescents to delay sexual initiation and substance use have been tested through rigorous evaluations. This is the protocol for the randomized controlled trial of the Asdzáán Be'eena' program, a teen pregnancy and substance use prevention program for young Native girls and their female caregivers. METHODS: N = 410 female adolescents ages 10-14 and their female caregivers will be enrolled in the study and randomized to the intervention or control arm. The intervention consists of the 11-session Asdzáán Be'eena' program. The control arm consists of mailed non-monetary incentives. All participants will complete evaluations at baseline and 3 follow-up timepoints (immediate, 6 and 12 months post intervention). Evaluations include measures to assess protective factors associated with delayed sexual initiation and substance use. DISCUSSION: This is one of the first rigorous evaluations of a gender-specific, culturally tailored teen pregnancy and substance use primary prevention program for Native girls and their female caregivers. If proven efficacious, Native communities will have a culturally appropriate program for promoting protective factors associated with delayed substance use and sexual risk taking. TRIAL REGISTRATION: NCT04863729 ; April 27, 2021.

Feasibility, Acceptability, and Preliminary Impact of Asdzáán Be'eená: An Intergenerational, Strength-Based, and Culturally Grounded Program to Improve the Health of Navajo Families.

Native American youth endure a complex interplay of factors that portend greater risk-taking behaviors and contribute to marked health disparities experienced in adolescence. The Asdzáán Be'eená ("Female Pathways" in Navajo) program was developed as a primary prevention program to prevent substance use and teen pregnancy among Navajo girls. The Asdzáán Be'eená program consists of 11 lessons delivered to dyads of girls ages 8 to 11 years and their female caregivers. Feasibility, acceptability, and preliminary impact on risk and protective factors were assessed through a pre-/post study design. Data were collected from girls and their female caregivers at baseline, immediate, and 3 months postprogram completion. Forty-seven dyads enrolled in the study, and 36 completed the 3-month evaluation. At 3 months postprogram, girls reported significant increases in self-esteem, self-efficacy, parent-child relationship, social support, cultural, and sexual health knowledge. Caregivers reported increased family engagement in Navajo culture and parent-child communication and improved child functioning (fewer internalizing and externalizing behaviors). Findings suggest Asdzáán Be'eená has potential to break the cycle of substance use and teen pregnancy in Native communities by improving protective and reducing risk factors associated with these adverse health outcomes. Additional rigorous efficacy trials are necessary to establish program effectiveness.

PI3K Inhibitors in Cancer: Clinical Implications and Adverse Effects.

The phospatidylinositol-3 kinase (PI3K) pathway is a crucial intracellular signaling pathway which is mutated or amplified in a wide variety of cancers including breast, gastric, ovarian, colorectal, prostate, glioblastoma and endometrial cancers. PI3K signaling plays an important role in cancer cell survival, angiogenesis and metastasis, making it a promising therapeutic target. There are several ongoing and completed clinical trials involving PI3K inhibitors (pan, isoform-specific and dual PI3K/mTOR) with the goal to find efficient PI3K inhibitors that could overcome resistance to current therapies. This review focuses on the current landscape of various PI3K inhibitors either as monotherapy or in combination therapies and the treatment outcomes involved in various phases of clinical trials in different cancer types. There is a discussion of the drug-related toxicities, challenges associated with these PI3K inhibitors and the adverse events leading to treatment failure. In addition, novel PI3K drugs that have potential to be translated in the clinic are highlighted.

Phosphoinositide 3-Kinase (PI3K) Reactive Oxygen Species (ROS)-Activated Prodrug in Combination with Anthracycline Impairs PI3K Signaling, Increases DNA Damage Response and Reduces Breast Cancer Cell Growth.

RIDR-PI-103 is a novel reactive oxygen species (ROS)-induced drug release prodrug with a self-cyclizing moiety linked to a pan-PI3K inhibitor (PI-103). Under high ROS, PI-103 is released in a controlled manner to inhibit PI3K. The efficacy and bioavailability of RIDR-PI-103 in breast cancer remains unexplored. Cell viability of RIDR-PI-103 was assessed on breast cancer cells (MDA-MB-231, MDA-MB-361 and MDA-MB-453), non-tumorigenic MCF10A and fibroblasts. Matrigel colony formation, cell proliferation and migration assays examined the migratory properties of breast cancers upon treatment with RIDR-PI-103 and doxorubicin. Western blots determined the effect of doxorubicin ± RIDR-PI-103 on AKT activation and DNA damage response. Pharmacokinetic (PK) studies using C57BL/6J mice determined systemic exposure (plasma concentrations and overall area under the curve) and T1/2 of RIDR-PI-103. MDA-MB-453, MDA-MB-231 and MDA-MB-361 cells were sensitive to RIDR-PI-103 vs. MCF10A and normal fibroblast. Combination of doxorubicin and RIDR-PI-103 suppressed cancer cell growth and proliferation. Doxorubicin with RIDR-PI-103 inhibited p-AktS473, upregulated p-CHK1/2 and p-P53. PK studies showed that ~200 ng/mL (0.43 µM) RIDR-PI-103 is achievable in mice plasma with an initial dose of 20 mg/kg and a 10 h T1/2. (4) The prodrug RIDR-PI-103 could be a potential therapeutic for treatment of breast cancer patients.

Azhe'é Bidziil (Strong Fathers): Study Protocol for the Pilot Evaluation of an American Indian Fatherhood Program to Improve the Health and Wellbeing of Diné (Navajo) Fathers.

INTRODUCTION: Considering the critical role that American Indian and Alaska Native (Native) men play in family and child health, there is an urgent need to collaborate with Native communities in developing interventions and policies to improve Native men's health status. This study aims to address a significant gap in research by designing and implementing a culturally grounded health promotion program to increase economic stability, promote positive parenting, and build healthy relationships among Native fathers. The Azhe'é Bidziil ("Strong Fathers") study protocol, developed in response to community advisory board feedback, illustrates a community-engaged approach to developing and implementing a fatherhood program in two Diné (Navajo) communities. METHODS/ANALYSIS: Azhe'é Bidziil was adapted from three evidence-based interventions developed in collaboration with Native communities. Intervention lessons were iteratively reviewed by a tribal working group to ensure that the content is culturally appropriate and relevant. A pre-post study will assess feasibility, acceptability, and satisfaction with the Azhe'é Bidziil intervention, as well as short-term impacts on positive parenting, economic stability, and healthy relationship outcomes. The intervention is composed of 12 weekly group sessions conducted with fathers (n = 750) that focus on developing knowledge and skills for positive father involvement, economic stability, and healthy relationships. Lesson content includes: honoring our roles as fathers, building healthy relationships, understanding the impact of historical trauma, goal-setting, and budgeting basics. Each of the 12 group lessons, consisting of 8-12 participants per group, last approximately 2 h. Eligible fathers or father figures are age ≥18 years, live within 50 miles of the participating Diné communities, and must be caregivers of at least one child ≤ 24 years. The outcomes for this study are acceptability, feasibility, and satisfaction with the intervention, as well as father involvement, quality of (co-) parenting communication, healthy relationships, fathers' engagement and communication with their children, protective factors (e.g., cultural connectedness and educational/career aspirations), and economic empowerment and stability. Participants will complete an outcome assessment at pre- and post-intervention (12 weeks later). DISCUSSION: This study protocol presents one of the few evaluations of a fatherhood intervention to increase economic stability, promote positive parenting, and build healthy relationships among Native fathers in rural tribal communities. Such a study is sorely needed to address the health disparities perpetuated by social and Indigenous determinants of health that Native men experience today. If proven efficacious, this pre- post-study will inform a large scale randomized controlled trial to evaluate intervention impact, and if proven efficacious may be disseminated widely in tribal nations. Study findings may also deepen our understanding of peer mentoring, Native men's health status, involvement with their children, co-parenting relationships, family relationships, cultural connectedness, and economic status. The data collected may also inform strategies to ensure acceptability, feasibility, and satisfaction of an intervention designed specifically for Native fathers.

BRAF Mutant Melanoma Adjusts to BRAF/MEK Inhibitors via Dependence on Increased Antioxidant SOD2 and Increased Reactive Oxygen Species Levels.

B-Rapidly Accelerated Fibrosarcoma (BRAF) mutations are found in about 50% of melanoma patients. Treatment with Food and Drug Administration (FDA)-approved BRAF and MAP/ERK kinase (MEK) inhibitors has improved progression free and overall survival of patients with BRAF mutant melanoma. However, all responders develop resistance typically within 1 year of treatment with these inhibitors. Evidence indicates that reactive oxygen species (ROS) levels are elevated after BRAF pathway inhibition treatment. We aim to decipher the role of mitochondrial antioxidant proteins relative to ROS levels and BRAF pathway inhibitor resistance. We observed BRAF mutant melanoma cells treated with the combination of a MEK inhibitor (trametinib) and a BRAF inhibitor (dabrafenib), exhibited elevated ROS levels, both in in vitro and in vivo melanoma models. We next generated trametinib- and dabrafenib-resistant (TDR) cells and found increased ROS levels after acquisition of resistance. An immunofluorescence experiment showed an increase of DNA damage in TDR cell lines. Furthermore, we observed that TDR cells increased superoxide dismutase 2 (SOD2), an antioxidant, at both mRNA and protein levels, with the upregulation of the transcription factor Nuclear Factor (NF)-κB. Knockdown of SOD2 significantly reduced the growth of BRAF pathway inhibitor-resistant cells. In addition, the results indicate that TDR cells can be re-sensitized to BRAF pathway inhibitors by the ROS scavenger, N-Acetyl Cysteine (NAC). Overall, these data indicate that BRAF pathway inhibitor-resistant cells can compensate for elevated ROS via increased expression of the antioxidant SOD2.