Joshua Mammen

Honokiol in Combination with Radiation Targets Notch Signaling to Inhibit Colon Cancer Stem Cells

Cancer stem cells are implicated in resistance to ionizing radiation (IR) and chemotherapy. Honokiol, a biphenolic compound has been used in traditional Chinese medicine for treating various ailments. In this study, we determined the ability of honokiol to enhance the sensitivity of colon cancer stem cells to IR. The combination of honokiol and IR suppressed proliferation and colony formation while inducing apoptosis of colon cancer cells in culture. There were also reduced numbers and size of spheroids, which was coupled with reduced expression of cancer stem cell marker protein DCLK1. Flow cytometry studies confirmed that the honokiol–IR combination reduced the number of DCLK1+ cells. In addition, there were reduced levels of activated Notch-1, its ligand Jagged-1, and the downstream target gene Hes-1. Furthermore, expression of components of the Notch-1 activating γ-secretase complex, presenilin 1, nicastrin, Pen2, and APH-1 was also suppressed. On the other hand, the honokiol effects were mitigated when the Notch intracellular domain was expressed. To determine the effect of honokiol–IR combination on tumor growth in vivo, nude mice tumor xenografts were administered honokiol intraperitoneally and exposed to IR. The honokiol–IR combination significantly inhibited tumor xenograft growth. In addition, there were reduced levels of DCLK1 and the Notch signaling–related proteins in the xenograft tissues. Together, these data suggest that honokiol is a potent inhibitor of colon cancer growth that targets the stem cells by inhibiting the γ-secretase complex and the Notch signaling pathway. These studies warrant further clinical evaluation for the combination of honokiol and IR for treating colon cancers. Mol Cancer Ther; 11(4); 963–72. ©2012 AACR.

Honokiol inhibits melanoma stem cells by targeting notch signaling

Melanoma is an aggressive disease with limited therapeutic options. Here, we determined the effects of honokiol (HNK), a biphenolic natural compound on melanoma cells and stemness. HNK significantly inhibited melanoma cell proliferation, viability, clonogenicity and induced autophagy. In addition, HNK significantly inhibited melanosphere formation in a dose dependent manner. Western blot analyses also demonstrated reduction in stem cell markers CD271, CD166, Jarid1b, and ABCB5. We next examined the effect of HNK on Notch signaling, a pathway involved in stem cell self‐renewal. Four different Notch receptors exist in cells, which when cleaved by a series of enzymatic reactions catalyzed by Tumor Necrosis Factor‐α‐Converting Enzyme (TACE) and γ‐secretase protein complex, results in the release of the Notch intracellular domain (NICD), which then translocates to the nucleus and induces target gene expression. Western blot analyses demonstrated that in HNK treated cells there is a significant reduction in the expression of cleaved Notch‐2. In addition, there was a reduction in the expression of downstream target proteins, Hes‐1 and cyclin D1. Moreover, HNK treatment suppressed the expression of TACE and γ‐secretase complex proteins in melanoma cells. To confirm that suppression of Notch‐2 activation is critical for HNK activity, we overexpressed NICD1, NICD2, and performed HNK treatment. NICD2, but not NICD1, partially restored the expression of Hes‐1 and cyclin D1, and increased melanosphere formation. Taken together, these data suggest that HNK is a potent inhibitor of melanoma cells, in part, through the targeting of melanoma stem cells by suppressing Notch‐2 signaling.

Honokiol induces cytotoxic and cytostatic effects in malignant melanoma cancer cells

BACKGROUND Melanomas are aggressive neoplasms with limited therapeutic options. Therefore, developing new therapies with low toxicity is of utmost importance. Honokiol is a natural compound that recently has shown promise as an effective anticancer agent. METHODS The effect of honokiol on melanoma cancer cells was assessed in vitro. Proliferation and physiologic changes were determined using hexosaminidase assay and transmission electron microscopy. Protein expression was assessed by immunoblotting. RESULTS Honokiol treatment inhibited cell proliferation and induced death. Electron microscopy showed autophagosome formation. Reduced levels of cyclin D1 accompanied cell-cycle arrest. Honokiol also decreased phosphorylation of AKT (known as protein kinase B) and mammalian target of rapamycin, and inhibited γ-secretase activity by down-regulating the expression of γ-secretase complex proteins, especially anterior pharynx-defective 1. CONCLUSIONS Honokiol is highly effective in inhibiting melanoma cancer cells by attenuating AKT/mammalian target of rapamycin and Notch signaling. These studies warrant further clinical evaluation for honokiol alone or with present chemotherapeutic regimens for the treatment of melanomas.

Efficacy of Neoadjuvant Carboplatin plus Docetaxel in Triple-Negative Breast Cancer: Combined Analysis of Two Cohorts

Purpose: Recent studies demonstrate that addition of neoadjuvant (NA) carboplatin to anthracycline/taxane chemotherapy improves pathologic complete response (pCR) in triple-negative breast cancer (TNBC). Effectiveness of anthracycline-free platinum combinations in TNBC is not well known. Here, we report efficacy of NA carboplatin + docetaxel (CbD) in TNBC. Experimental Design: The study population includes 190 patients with stage I–III TNBC treated uniformly on two independent prospective cohorts. All patients were prescribed NA chemotherapy regimen of carboplatin (AUC 6) + docetaxel (75 mg/m2) given every 21 days × 6 cycles. pCR (no evidence of invasive tumor in the breast and axilla) and residual cancer burden (RCB) were evaluated. Results: Among 190 patients, median tumor size was 35 mm, 52% were lymph node positive, and 16% had germline BRCA1/2 mutation. The overall pCR and RCB 0 + 1 rates were 55% and 68%, respectively. pCRs in patients with BRCA-associated and wild-type TNBC were 59% and 56%, respectively (P = 0.83). On multivariable analysis, stage III disease was the only factor associated with a lower likelihood of achieving a pCR. Twenty-one percent and 7% of patients, respectively, experienced at least one grade 3 or 4 adverse event. Conclusions: The CbD regimen was well tolerated and yielded high pCR rates in both BRCA-associated and wild-type TNBC. These results are comparable with pCR achieved with the addition of carboplatin to anthracycline–taxane chemotherapy. Our study adds to the existing data on the efficacy of platinum agents in TNBC and supports further exploration of the CbD regimen in randomized studies. Clin Cancer Res; 23(3); 649–57. ©2016 AACR.

Impact of neoadjuvant chemotherapy on axillary nodal involvement in patients with clinically node negative triple negative breast cancer.

We evaluated the impact of Neoadjuvant Chemotherapy (NAC) versus primary surgery (PS) on axillary disease burden/surgery in clinically node negative Triple Negative Breast Cancer (TNBC).

Are university-based residency training programs lacking in resident education of proper diagnosis and treatment for common skin and breast lesions?

BACKGROUND Skin and breast cancers are the 2 most common malignancies in US women. Early detection with appropriate therapy is essential in improving survival rates. The aim of this study was to evaluate and compare general surgery (GS) and family medicine (FM) residents in their ability to identify and appropriately treat common skin and breast lesions. METHODS Thirty-three-question, institutional review board-approved, Web-based surveys (1 breast and 1 skin survey) were each sent to 244 GS and 452 FM training programs (both university-based and community-based programs) uniformly distributed across the United States. Each survey included demographics and 20 multiple-choice questions (10 lesion identification questions and 10 corresponding treatment questions). RESULTS A total of 374 completed resident surveys were collected (242 FM, 132 GS). Respondents were uniformly distributed geographically (55.9% women, 44.1% men; 54.2% community based, 45.8% university based). GS residents correctly identified 82.7% of lesions compared with 83.3% for FM residents (P = .89) and correctly treated 76.8% of lesions compared with 75.4% for FM residents (P = .81). No significant identification or treatment differences were noted by postgraduate year (PGY), but both GS and FM residents had lower accuracy of correct treatment identification compared with lesion identification, which was significant for GS PGY 2 residents (P = .02), FM PGY 2 residents (P = .03), and FM PGY 2 residents (P = .03). University-based GS residents had a more significant disparity between correct identification and correct treatment (83.6% vs 74.6%, P = .03) compared with community-based GS residents (80.4% vs 74.6%, P = .11). Both university-based and community-based FM residents had significant disparities in this comparison (university-based FM residents with 82.4% vs 69.8%, P = .02, vs community-based FM residents with 86.7% vs 74.5%, P = .04). CONCLUSIONS Both GS and FM residents incorrectly treated more lesions than they diagnosed. This diagnosis-treatment disparity was more pronounced among university-based residents. Validation of this observation may better identify potential training deficiencies in breast and skin oncology to enhance GS resident education.

Secondary review of external histopathology on cutaneous oncology patients referred for sentinel lymph node biopsy: how often does it happen and is it worth it?

We reviewed the data on external histopathology review for patients referred to our institution for sentinel lymph node biopsy (SLNB) associated with melanoma, Merkel cell carcinoma and adnexal carcinoma.

Abstract P3-06-16: Thrombocytopenia is associated with pathological complete response to neoadjuvant carboplatin/docetaxel chemotherapy in BRCA wild type triple negative breast cancer

Introduction: Growing evidence demonstrates activity of neoadjuvant carboplatin in triple negative breast cancer (TNBC). Underlying germline and somatic Homologous Recombination (HR) repair deficiency may predict response to DNA damaging agents like platinum compounds in TNBC. Certain DNA repair machinery genes (Fanconi Anemia gene) are also involved in the maintenance of hematopoetic stem cell (HSC) function and impaired repair of DNA double strand breaks can lead to HSC and progenitor cell dysfunction. Thus, in presence of HR defects DNA damaging chemotherapy may lead to unique hematological toxicity. It is also possible that in presence of HR defects breast cancer response and hematological toxicity with DNA damaging agents will parallel each other. Aim: To evaluate the impact of hematological toxicity on response to neoadjuvant Carboplatin/Docetaxel chemotherapy in patients with sporadic and BRCA associated TNBC utilizing clinical and BRCA mutation data from a prospective TNBC registry. Methods: 288 patients with Stage I (T>1cm) II and III TNBC were enrolled on a multisite prospective registry between 3/2011 to 4/2014, out of which 49 patients received neoadjuvant Carboplatin AUC 6 + Docetaxel 75mg/m 2 every 21 days (4-6 cycles) and have undergone breast surgery. Carboplatin was dosed using the modified Cockcroft-Gault formula. Hematologic toxicity was graded using the CTCAE version 4.03. All patients received prophylactic pegfilgrastim on day 2. Pathological complete response (pCR) was defined as absence of invasive disease in the breast and axilla. All patients underwent comprehensive BRACAnalysis®(Myriad). Results: For the 49 eligible patients median age was 50 years, median weight was 172 lbs, 18% were African American, and 37% had LN+ disease. 26% (13 /49) of patients carried deleterious BRCA mutation (9 BRCA 1, 4 BRCA 2). pCR of the cohort was 65%. Overall 61%, 96%, and 12 % patients demonstrated > Grade1 thrombocytopenia (Tp), anemia, or neutropenia, respectively; 4%, 6%, and 6% patients demonstrated grade 3/4 thrombocytopenia, anemia, or neutropenia, respectively. There was no association between pCR and anemia or neutropenia. Carboplatin dose reductions/delays/omission was more common in patients with Tp compared to patients without Tp (33% vs. 5%; p=0.02). Patients with Tp were more likely to achieve a pCR compared to patients without Tp (85% vs. 47%; p=0.013). 77% of BRCA carriers and 64% of BRCA wild type TNBC demonstrated Tp (NS). pCR rates in BRCA wild type patients with and without Tp were 82% and 47%, respectively (p=0.041). pCR rates in BRCA mutation carriers with and without Tp were 89% and 50%, respectively (p=0.20). On multivariable platelet count was independently associated with pCR (p=0.001)Conclusions: Tp was associated with decreased dose delivery of carboplatin but an improved pCR in BRCA wild type TNBC. Comprehensive assessment of HR defects beyond germline BRCA mutation status may be required to elucidate the biological process that explains this observation. Tp may be a harbinger of underlying HR deficiency and further correlative studies exploring this association of Tp with pathological response to carboplatin in TNBC are warranted. Citation Format: Priyanka Sharma, Benjamin C Powers, Bruce F Kimler, Claire Ward, Jennifer R Klemp, Carol S Connor, Marilee K McGinness, Joshua MV Mammen, Jamie L Wagner, Qamar J Khan, Roy A Jensen, Andrew K Godwin, Carol J Fabian. Thrombocytopenia is associated with pathological complete response to neoadjuvant carboplatin/docetaxel chemotherapy in BRCA wild type triple negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-16.

Speed Mentoring: An Innovative Method to Meet the Needs of the Young Surgeon

OBJECTIVE Speed mentoring has recently been used by several medical organizations as a strategy to establish mentoring relationships, which are felt to be critically important in the development of the surgeon. This study assesses a surgical speed-mentoring program at the 2015 American College of Surgeons (ACS) Clinical Congress. DESIGN A steering committee designed the speed-mentoring program to match 60 ACS Resident and Associate Society mentees with a mix of junior and senior leadership of ACS. Each mentee met with 5 mentors for 10 minutes each during the 1 hour session. After participation in the activity, surveys were provided to assess the event. The survey included forced-choice questions using Likert-scales as well as open-ended questions. Mentor and mentee responses were compared using Medcalc software using comparison of means and comparison of proportion, with p < 0.05 considered significant. SETTING The study was undertaken at the 2015 ACS Clinical Congress. PARTICIPANTS A total of 60 mentors and 49 mentees participated in the inaugural ACS Speed-Mentoring activity. The postactivity survey was completed by 54 mentors (90%) and 39 mentees (79.5%). RESULTS There was a high level of satisfaction with the activity, with 100% of mentors and mentees stating that they would recommend the activity to a colleague. There was overall high satisfaction with the organization of the session by both the mentors and the mentees although the mentors were more likely to feel that they needed more time for each interaction. More mentees (93%) than mentors (68.5%) felt they were likely to develop a mentoring relationship with one of their matches outside of the organized session. CONCLUSIONS We demonstrated that a speed-mentoring event at a national surgical meeting offers an effective platform for mentoring and is mutually beneficial to both mentors and mentees. Data collected here will be used to modify and improve the design of future speed-mentoring sessions.

Abstract P1-01-02: Axillary Reverse Mapping: A Prospective Study on Feasibility, Oncologic Safety, and Lymphedema Prevention.

Withdrawn by Author Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-02.