In 165 women with breast cancer who were candidates for mastectomy because the largest diameter of the tumor was 3 cm or more, we administered primary chemotherapy in the attempt to substitute conservative for mutilating surgery. We then systematically quantitated tumor reduction by clinical, radiologic, and histopathologic evaluations. Five consecutive groups of 33 patients received cyclophosphamide, methotrexate, and fluorouracil (CMF); fluorouracil, doxorubicin (Adriamycin), and cyclophosphamide (FAC); or fluorouracil, epirubicin, and cyclophosphamide (FEC). The regimens for the five groups were as follows: group 1, three cycles of CMF; group 2, four cycles of CMF; group 3, three cycles of FAC; group 4, four cycles of FAC; and group 5, three cycles of FEC. In response to primary chemotherapy, 157 of the 161 assessable patients showed measurable tumor shrinkage; progressive disease was documented in four. Tumor shrinkage to less than 3 cm was documented in 127 (81%) of the 157 women subjected to surgery, thus allowing a breast-saving procedure, rather than modified radical mastectomy, in these 127 women. Histopathologic complete remission was documented in seven patients. Tumor response was unrelated to age, menopausal status, DNA content (ploidy), [3H]thymidine-labeling index, drug combination used, or number of treatment cycles in excess of three. The degree of response was inversely proportional to the initial tumor size, and the frequency of response was greater in receptor-negative tumors. Severe vomiting and hair loss were less frequent with CMF than with anthracycline-containing regimens, and the frequency of severe leukopenia and thrombocytopenia was minimal. Our results challenge the classical indication for primary mastectomy by showing that use of full-dose primary chemotherapy, sequentially combined with conservative surgery and radiation, can offer an effective and safe alternative to women concerned about the preservation of body integrity.

RANK expression is associated with poor prognosis in breast cancer even though its therapeutic potential remains unknown. RANKL and its receptor RANK are downstream effectors of the progesterone signaling pathway. However, RANK expression is enriched in hormone receptor negative adenocarcinomas, suggesting additional roles for RANK signaling beyond its hormonedependent function. Here, to explore the role of RANK signaling once tumors have developed, we use the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT), which mimics RANK and RANKL expression patterns seen in human breast adenocarcinomas. Complementary genetic and pharmacologic approaches demonstrate that therapeutic inhibition of RANK signaling drastically reduces the cancer stem cell pool, decreases tumor and metastasis initiation, and enhances sensitivity to chemotherapy. Mechanistically, genome-wide expression analyses show that anti-RANKL therapy promotes lactogenic differentiation of tumor cells. Moreover, RANK signaling in tumor cells negatively regulates the expression of Ap2 transcription factors, and enhances the Wnt agonist Rspo1 and the Sca1-population, enriched in tumor-initiating cells. In addition, we found that expression of TFAP2B and the RANK inhibitor, OPG, in human breast cancer correlate and are associated with relapse-free tumors. These results support the use of RANKL inhibitors to reduce recurrence and metastasis in breast cancer patients based on its ability to induce tumor cell differentiation. Cancer Res; 76(19); 5857-69. Ó2016 AACR.

The anticancer drug ABTL0812 induces ER stress-mediated cytotoxic autophagy by increasing dihydroceramide levels in cancer cells-Manuscript Draft-Manuscript Number: KAUP-2019-0426R3 Full Title: The anticancer drug ABTL0812 induces ER stress-mediated cytotoxic autophagy by increasing dihydroceramide levels in cancer cells

SummaryTaxanes are a mainstay of treatment for breast cancer, but resistance often develops followed by metastatic disease and mortality. Aiming to reveal the mechanisms underlying taxane resistance, we used breast cancer patient-derived orthoxenografts (PDX). Mimicking clinical behavior, triple-negative breast tumors (TNBCs) from PDX models were more sensitive to docetaxel than luminal tumors, but they progressively acquired resistance upon continuous drug administration. Mechanistically, we found that a CD49f+ chemoresistant population with tumor-initiating ability is present in sensitive tumors and expands during the acquisition of drug resistance. In the absence of the drug, the resistant CD49f+ population shrinks and taxane sensitivity is restored. We describe a transcriptional signature of resistance, predictive of recurrent disease after chemotherapy in TNBC. Together, these findings identify a CD49f+ population enriched in tumor-initiating ability and chemoresistance properties and evidence a drug holiday effect on the acquired resistance to docetaxel in triple-negative breast cancer.

Most breast cancers exhibit low immune infiltration and are unresponsive to immunotherapy. We hypothesized that inhibition of the receptor activator of nuclear factor-κB (RANK) signaling pathway may enhance immune activation. Here we report that loss of RANK signaling in mouse tumor cells increases leukocytes, lymphocytes, and CD8+ T cells, and reduces macrophage and neutrophil infiltration. CD8+ T cells mediate the attenuated tumor phenotype observed upon RANK loss, whereas neutrophils, supported by RANK-expressing tumor cells, induce immunosuppression. RANKL inhibition increases the anti-tumor effect of immunotherapies in breast cancer through a tumor cell mediated effect. Comparably, pre-operative single-agent denosumab in premenopausal early-stage breast cancer patients from the Phase-II D-BEYOND clinical trial (NCT01864798) is well tolerated, inhibits RANK pathway and increases tumor infiltrating lymphocytes and CD8+ T cells. Higher RANK signaling activation in tumors and serum RANKL levels at baseline predict these immune-modulatory effects. No changes in tumor cell proliferation (primary endpoint) or other secondary endpoints are observed. Overall, our preclinical and clinical findings reveal that tumor cells exploit RANK pathway as a mechanism to evade immune surveillance and support the use of RANK pathway inhibitors to prime luminal breast cancer for immunotherapy.