Future treatment strategies for metastatic breast cancer: curable or incurable?

ERCC6L facilitates the onset of mammary neoplasia and promotes the high malignance of breast cancer by accelerating the cell cycle

BACKGROUND

Breast cancer (BC) is the leading cause of morbidity and the second leading cause of death among female malignant tumors. Although available drugs have been approved for the corresponding breast cancer subtypes (ER-positive, HER2+) currently, there are still no effective targeted drugs or treatment strategies for metastatic breast cancer or triple-negative breast cancer that lack targets. Therefore, it is urgent to discover new potential targets. ERCC6L is an essential protein involved in chromosome separation during cell mitosis. However, the effect of ERCC6L on the tumorigenesis and progression of breast cancer is unclear.

METHODS AND RESULTS

Here, we found that ERCC6L was highly expressed in breast cancer, especially in TNBC, which was closely related to poor outcomes of patients. An ERCC6L conditional knockout mouse model was first established in this study, and the results confirmed that ERCC6L was required for the development of the mammary gland and the tumorigenesis and progression of mammary gland cancers. In in vitro cell culture, ERCC6L acted as a tumor promoter in the malignant progression of breast cancer cells. Overexpression of ERCC6L promoted cell proliferation, migration and invasion, while knockdown of ERCC6L caused the opposite results. Mechanistically, ERCC6L accelerated the cell cycle by regulating the G2/M checkpoint signalling pathway. Additionally, we demonstrated that there is an interaction between ERCC6L and KIF4A, both of which are closely related factors in mitosis and are involved in the malignant progression of breast cancer.

CONCLUSIONS

We first demonstrated that ERCC6L deficiency can significantly inhibit the occurrence and development of mammary gland tumors. ERCC6L was found to accelerate the cell cycle by regulating the p53/p21/CDK1/Cyclin B and PLK/CDC25C/CDK1/Cyclin B signalling pathways, thereby promoting the malignant progression of breast cancer cell lines. There was a direct interaction between KIF4A and ERCC6L, and both are closely associated with mitosis and contribute to growth and metastasis of breast tumor. To sum up, our results suggest that ERCC6L may be used as a promising target for the treatment of BC.

The therapeutic potential of immunotherapy in the treatment of breast cancer: Rational strategies and recent progress

The second leading cause of cancer death in women worldwide is breast cancer (BC), and despite significant advances in BC therapies, a significant proportion of patients develop metastasis and disease recurrence. Currently used treatments, like radiotherapy, chemotherapy, and hormone replacement therapy, result in poor responses and high recurrence rates. Alternative therapies are therefore needed for this type of cancer. Cancer patients may benefit from immunotherapy, a novel treatment strategy in cancer treatment. Even though immunotherapy has been successful in many cases, some patients do not respond to the treatment or those who do respond relapse or progress. The purpose of this review is to discuss several different immunotherapy approaches approved for the treatment of BC, as well as different strategies for immunotherapy for the treatment of BC.

Efficacy of Metformin as Adjuvant Therapy in Metastatic Breast Cancer Treatment

Background: Metformin has been reported to have an anti-tumorigenic impact against metastatic breast cancer (MBC) cells through several mechanisms. Its effect can be evaluated by using many variables such as the response rate (RR) as well as the progression-free survival (PFS). Materials and methods: A prospective study was conducted to investigate and estimate the metformin effect on MBC. About 107 subjects were included in the study and were divided into two groups: Group A included non-diabetic MBC patients treated with metformin in conjunction with chemotherapy and group B included those treated with chemotherapy alone. Both PFS and RR were used as a criteria to evaluate the treatment outcome. Associated adverse effects of metformin were also assessed. Results: The average age of the participants in group A and group B was 50 vs. 47.5, respectively. No significant differences were detected between both cohorts concerning RR levels (regression disease (RD) 27.8% vs. 12.5%, stationary disease (SD) 44.4% vs. 41.7%, progression disease (PD) 27.8% vs. 45.8%, respectively, p = 0.074). Moreover, PFS showed no significant difference between both groups (p = 0.753). There was no significant correlation between metformin concentration and their adverse effects on the study participants. Conclusion: Metformin as an adjuvant therapy to MBC undergoing chemotherapy showed no significant survival benefit as determined by RR and PFS.

Platelet isoform of phosphofructokinase accelerates malignant features in breast cancer

The platelet isoform of phosphofructokinase (PFKP) is one of the key enzymes in the glycolytic pathway. PFKP is highly expressed in several cancers, and it has been reported to be involved in the progression of cancer cells. However, its oncological role in breast cancer (BC) remains unclear. The present study aimed to evaluate the function of PFKP in BC cells and its expression level in patients with BC. Firstly, the mRNA and protein expression of PFKP was evaluated in BC and non‑cancerous mammary cell lines. Polymerase chain reaction (PCR) array analysis was conducted to evaluate the correlation between PFKP and 84 cancer‑related genes. Then, PFKP knockdown was conducted using small interfering RNA, and cell proliferation, invasiveness and migration were analyzed. Furthermore, the association between PFKP mRNA expression and clinicopathological factors was investigated in 167 patients with BC. PFKP was highly expressed in estrogen receptor‑negative and human epidermal growth factor receptor 2‑negative BC cell lines. PCR array analysis demonstrated that the expression level of PFKP was significantly correlated with that of transforming growth factor‑β1 and MYC proto‑oncogene. PFKP knockdown significantly decreased the proliferation and invasiveness of MCF7, SK‑BR‑3, and MDA‑MB‑231 cells. Furthermore, cell migration was inhibited in SK‑BR‑3 and MDA‑MB‑231 cells. In the clinical specimens, patients with T2/T3/T4, lymph node metastasis, or stage II/III/IV exhibited higher expression of PFKP mRNA than patients with less severe disease. In conclusion, the present findings indicated that PFKP is involved in promoting tumor‑progressive oncological roles in BC cells across different subtypes and is considered a possible novel therapeutic target for BC.

Synaptotagmin 13 Is Highly Expressed in Estrogen Receptor-Positive Breast Cancer

Background: Accumulating evidence indicates tumor-promoting roles of synaptotagmin 13 (SYT13) in several cancers; however, no studies have investigated its expression in breast cancer (BC). This study aimed to clarify the significance of SYT13 in BC. Methods: SYT13 mRNA expression levels were evaluated in BC cell lines. Polymerase chain reaction (PCR) array analysis was conducted to determine the correlation between expression levels of SYT13 and other tumor-associated genes. Then, the association of SYT13 expression levels in the clinical BC specimens with patients’ clinicopathological factors was evaluated. These findings were subsequently validated using The Cancer Genome Atlas (TCGA) database. Results: Among 13 BC cell lines, estrogen receptor (ER)-positive cells showed higher SYT13 mRNA levels than ER-negative cells. PCR array analysis revealed positive correlations between SYT13 and several oncogenes predominantly expressed in ER-positive BC, such as estrogen receptor 1, AKT serine/threonine kinase 1, and cyclin-dependent kinases 4. In 165 patients, ER-positive specimens exhibited higher SYT13 mRNA expression levels than ER-negative specimens. The TCGA database analysis confirmed that patients with ER-positive BC expressed higher SYT13 levels than ER-negative patients. Conclusion: This study suggests that SYT13 is highly expressed in ER-positive BC cells and clinical specimens, and there is a positive association of SYT13 with the ER signaling pathways.

MZB1 expression indicates poor prognosis in estrogen receptor-positive breast cancer

Breast cancer (BC) is the most common malignant tumor in females. Development of novel biomarkers or therapeutic targets may contribute toward the improvement of a patient's prognosis. Marginal zone B and B1 cell-specific protein (MZB1) is an unfolded protein response-related chaperone and mainly exists in the endoplasmic reticulum of B lymphocytes, although little is known regarding its role in BC cells. The present study aimed to investigate the significance of MZB1 expression in BC. To begin with, MZB1 mRNA expression levels in 13 BC cell lines and two non-cancerous mammary cell lines were evaluated. Next, mRNA and protein expression of MZB1 in BC patient tumor specimens was evaluated to assess the association between expression and clinicopathological factors or prognosis. MZB1 mRNA expression levels were detectable in four estrogen receptor (ER)-positive BC cell lines. When ratios of MZB1 mRNA expression levels between BC and non-cancerous specimens were evaluated, patients with stage III disease exhibited a higher ratio than patients with stage 0/I/II disease (P=0.009). Using immunohistochemistry, patients with ER-positive BC more frequently expressed MZB1, compared with patients with ER-negative BC (P=0.003). In patients with ER-positive BC, patients with MZB1-positive BC experienced shorter disease-free survival (DFS) times than patients with negative BC (P=0.026). Multivariate analysis of DFS demonstrated that MZB1 positivity was an independent prognostic factor (P=0.022). The results of the present study suggested that MZB1 expression may be associated with a more advanced stage of BC. Furthermore, in patients with ER-positive BC, MZB1 may be a potential prognostic marker.

"I'd Want to Know, Because a Year's Not a Long Time to Prepare for a Death": Role of Prognostic Information in Shared Decision Making among Women with Metastatic Breast Cancer

Context: Increasing emphasis on patient-centered care has led to highlighted importance of shared decision making, which better aligns medical decisions with patient care preferences. Effective shared decision making in metastatic breast cancer (MBC) treatment requires prognostic understanding, without which patients may receive treatment inconsistent with personal preferences. Objectives: To assess MBC patient and provider perspectives on the role of prognostic information in treatment decision making. Methods: We conducted semi-structured interviews with MBC patients and community oncologists and separate focus groups involving lay navigators, nurses, and academic oncologists. Qualitative analysis utilized a content analysis approach that included a constant comparative method to generate themes. Results: Of 20 interviewed patients with MBC, 30% were African American. Academic oncologists were mostly women (60%), community oncologists were all Caucasian, and nurses were all women and 28% African American. Lay navigators were all African American and predominately women (86%). Five emergent themes were identified. (1) Most patients wanted prognostic information but differed in when they wanted to have this conversation, (2) Emotional distress and discomfort was a critical reason for not discussing prognosis, (3) Religious beliefs shaped preferences for prognostic information, (4) Health care professionals differed on prognostic information delivery timing, and (5) Providers acknowledged that an individualized approach taking into account patient values and preferences would be beneficial. Conclusion: Most MBC patients wanted prognostic information, yet varied in when they wanted this information. Understanding why patients want limited or unrestricted prognostic information can inform oncologists' efforts toward shared decision making.

PSMA-Targeting Positron Emission Agents for Imaging Solid Tumors Other Than Non-Prostate Carcinoma: A Systematic Review

Despite its name, prostate-specific membrane antigen (PSMA) has been shown using immunohistochemistry (IHC) to also be over-expressed in the tumor neovasculature of a wide variety of solid tumors other than prostate carcinoma. Accordingly, positron-emitting radiolabeled small molecules targeting PSMA, initially developed for positron emission tomography in prostate carcinomas, are currently being explored for their staging and restaging potential as an alternative imaging modality in other solid tumor types where 18-F-fluorodeoxyglucose (FDG)-PET imaging has low diagnostic accuracy. In this paper, the currently available literature in this field is reviewed. Preliminary, mainly retrospective studies are encouraging, with evidence of improved diagnostic sensitivity and specificity in clear cell renal carcinoma, glioma, and hepatocellular carcinoma, leading to a change in patient management in several patients. However, the results published thus far warrant confirmation by larger prospective studies additionally assessing the longitudinal impact on patient outcomes.

Overexpression of Derlin 3 is associated with malignant phenotype of breast cancer cells

Breast cancer (BC) is the most common malignant tumor among women worldwide. Development of novel molecular targets is important to improve prognosis of BC patients. Derlin 3 (DERL3) gene is a member of derlin family, and its coding protein is critical to the endoplasmic reticulum-associated degradation mechanism. However, its oncological role in breast cancer remains unclear. This study evaluated DERL3 expression and function in BC. We analyzed DERL3 mRNA in 13 BC and two non-cancerous cell lines, and explored effects of DERL3 knockdown on BC proliferation, invasion and migration. We also evaluated correlation of DERL3 mRNA expression levels with clinicopathological factors and prognosis in 167 BC patients. DERL3 mRNA expression was detected in five (38%) BC cell lines. Inhibiting DERL3 expression significantly decreased proliferation and invasion in BC cells. Specimens from patients with lymph node metastasis had higher DERL3 mRNA expression than those without (P=0.030). Patients in the highest quartile for DERL3 mRNA expression (n=42) were more likely to experience shorter overall survival than other patients (P=0.032). These findings indicate that DERL3 promotes malignant phenotype in BC cells. DERL3 may serve as a potential prognostic marker and therapeutic target for BC.

乳腺癌肝转移治疗现状及射频消融的应用及前景

乳腺癌是女性发病率和死亡率最高的恶性肿瘤. 乳腺癌晚期常发生转移, 好发转移部位依次为骨、肺、肝等. 近年来, 虽然乳腺癌肝转移(breast cancer liver metastases, BCLM)治疗成功率逐渐提高, 但是BCLM的预后仍然较差. 目前, BCLM的治疗方式尚未成熟, 主要以手术切除、化疗、射频消融(radiofrequency ablation, RFA)治疗、肝动脉栓塞灌注化疗等为主. 本文回顾分析了国内外有关治疗BCLM治疗的文献, 其中重点关注BCLM局部治疗中的RFA治疗, 分析RFA治疗BCLM的应用及前景.

Sonographic Detection of Metastatic Breast Cancer in the Liver

Sonography is an effective imaging modality for detecting the presence of breast cancer that has metastasized to other organs. Early determination of the presence of these metastatic lesions has proved essential in improving the survival of patients with this disease. This case study presents a patient who was diagnosed with breast cancer, treated, and considered cancer free 9 months prior to the sonogram presented. Within these 9 months, the breast cancer had metastasized to the liver, where it was initially detected on a right upper quadrant sonogram, evaluated further by computed tomography, and definitively diagnosed by histopathology following core needle biopsy.

A retrospective analysis of the activity and safety of oral Etoposide in heavily pretreated metastatic breast cancer patients

Metastatic breast cancer (MBC) patients derive benefit from chemotherapy, but options become limited after several prior chemotherapeutic regimens. Oral etoposide (VP-16) has previously been found to be clinically active in MBC patients in phase II trials. However, with increasing availability of other drugs, etoposide use has declined in spite of its unfavorable toxicity profile probably being overestimated. We therefore evaluated the clinical benefit and safety of oral etoposide in a population of MBC patients who had failed multiple regimens of currently used therapies. Sixty-six patients with MBC previously treated with a median of eight (range 2-13) regimens of therapy were eligible for the study. Patients received 50 mg/day oral etoposide in 20-day cycles with 1-week of rest. All patients were evaluated for clinical benefit (clinical benefit rate [CBR], complete response, partial response, and disease stabilization >24 weeks), progression-free survival (PFS), overall survival (OS), and toxicities. Median PFS was 4 months, CBR was 18% (overall response rate 4%), and median OS from the start of treatment was 11 months. Little clinically significant or high-grade toxicity were observed. No patients withdrew from treatment due to etoposide-induced toxicity. The favorable clinical response, low toxicity, and low cost of the drug suggest that etoposide is a viable option for patients with heavily pretreated MBC.

Early detection of metastatic disease in asymptomatic breast cancer patients with whole-body imaging and defined tumour marker increase

BACKGROUND

Follow-up care in breast cancer is still an issue of debate. Diagnostic methods are more sensitive, and more effective therapeutic options are now available. The risk of recurrence is not only influenced by tumour stage but also by the different molecular subtypes. This study was performed to evaluate the use of whole-body imaging combined with tumour marker monitoring for the early detection of asymptomatic metastatic breast cancer (MBC).

METHODS

This analysis was performed as part of a follow-up study evaluating 813 patients with a median follow-up of 63 months. After primary therapy, all patients underwent tumour marker monitoring for CEA, CA 15-3 and CA 125 at 6-week intervals within an intensified diagnostic aftercare algorithm. A reproducible previously defined increase was considered as a strong indicator of MBC. From 2007 to 2010, 44 patients with tumour marker increase underwent whole-body magnetic resonance imaging and/or an FDG-PET/CT scan. Histological clarification and/or imaging follow-up were done.

RESULTS

Metastases were detected in 65.9% (29/44) of patients, 13.6% (6/44) had secondary malignancies besides breast cancer and 20.5% (9/44) had no detectable malignancy. Limited disease was found in 24.1% (7/29) of patients. Median progression-free survival of MBC was 9.2 months and median overall survival was 41.1 months. The 3- and 5-year survival rates were 64.2% and 40.0%, respectively.

CONCLUSIONS

A reproducible tumour marker increase followed by whole-body imaging is highly effective for early detection. By consequence, patients might benefit from earlier detection and improved therapeutic options with a prolonged survival.

Optimal surveillance for postoperative metastasis in breast cancer patients

PURPOSE

To establish an optimal surveillance schedule after surgery for breast cancer, patients included in an institutional database were retrospectively investigated with respect to the first metastatic site and timing of recurrence.

PATIENTS AND METHODS

We investigated 11,676 pT1-4pN0-2M0 breast cancer patients treated from 1985 to 2009 and followed up until June 2014. Our surveillance protocol included physician visits and examinations with bone scans, liver echography, chest roentgenography and laboratory tests. We evaluated the liver, bones, lungs and pleura as surveillance covering sites (SCS) in addition to parameters such as time points exceeding 80 % with respect to the accumulated percentage of patients of recurrence and the number of surveillance per one recurrence (NSR), calculated by dividing the number of patients at risk of recurrence at the start of a particular time frame by the number of patients of recurrence at SCS within that period.

RESULTS

There were a total of 1,962 recurrent patients, including 601 patients with locoregional recurrence, nine patients with recurrence in the opposite breast, 1,349 patients with recurrence at distant sites and three unknown patients. The number of patients with the bones, lungs, liver and pleura as the first site of recurrence was 447, 324, 144 and 69, respectively, and 72.9 % of the distant metastatic lesions belonged to SCS. The five-year overall survival rate after recurrence among the patients with single recurrent site was longer than that observed among the patients with multiple sites of recurrence (43.3 vs 25.3 %; p < 0.0001). In addition, more than 80 % of the patients of liver metastasis were detected within 5 years after surgery, while 80 % of the patients of pleura metastasis were detected within 10 years. The NSR was below 200 for the 10-year period, as was the NSR of the patients with lymph node metastasis and a positive hormone receptor status. In contrast, the NSR of the patients with a negative hormone receptor status was above 200 after 5 years.

CONCLUSIONS

In this study, the prognosis of the patients with a single site of recurrence was superior to that of the patients with multiple sites. Curable patients with distant metastases included those with single metastatic sites. The optimal surveillance schedule should be established taking into consideration that the incidence of metastasis differs among metastatic sites during follow-up.

Bilateral synchronous adrenal metastasis of invasive ductal carcinoma treated with multimodality therapy including adrenalectomy and oophorectomy

A 38-year-old woman presented with a mass in the left breast. Biopsy of the lesion revealed invasive ductal carcinoma. Bilateral adrenal metastasis was detected in whole body positron emission tomography scanning. Needle biopsy of the left adrenal lesion proved infiltration of malignant cells from breast carcinoma. After eight cycles of neoadjuvant (preoperative) chemotherapy, mastectomy, bilateral adrenalectomy, and bilateral oopherectomy were performed. No further hormonal treatment was recommended due to the resection of both adrenal glands and ovaries. The patient is still followed without any sign of progression. To our knowledge, this is the first case representing multimodality approach to breast cancer with bilateral synchronous adrenal metastasis. Patients with oligometastatic disease may benefit from aggressive treatment including local therapies.

Epithelial-to-mesenchymal transition: what is the impact on breast cancer stem cells and drug resistance

There is increasing interest in cancer stem cells (CSCs) and their role in cancer progression. Recently, CSCs have been identified in brain, skin, and intestinal tumors and it has been suggested that these CSCs are responsible for tumor growth and metastasis. In breast cancer fatality is often due to the development of metastatic disease (MBC). Almost 30% of early breast cancer patients eventually develop MBC and in 90% of these multi-drug resistance (MDR) occurs. This could be attributed to the presence of breast cancer stem cells (BCSCs). Epithelial-to-mesenchymal transition (EMT) is a process known to contribute to metastasis in cancer and it is mainly characterized by loss of E-cadherin expression. The TGF-β signaling pathway has an established role in promoting EMT by down-regulating E-cadherin via a number of transcription factors, such as Twist, Snail and Slug. EMT has also been reported to produce cells with stem cell-like properties. Definition of the exact molecular mechanisms that are involved in the generation of stem cells through EMT could lead to the identification of new potential therapeutic targets and enable the development of more efficient strategies for particular patient groups. In this review we discuss what is known about the relationship between EMT, BCSCs and MDR.

Moscatilin inhibits migration and metastasis of human breast cancer MDA-MB-231 cells through inhibition of Akt and Twist signaling pathway

Breast cancer metastasis is more resistant to chemotherapy and radiotherapy than is cancer of the visceral tissues; therefore, new treatment strategies are urgently needed. Moscatilin, derived from the orchid Dendrobrium loddigesii, has shown anticancer activity. We evaluated the mechanism by which moscatilin suppresses the migration and metastasis of human breast cancer MDA-MB-231 cells in vitro and in vivo. We demonstrated that moscatilin significantly inhibits MDA-MB-231 cell migration by using scratch assays and Boyden chambers. Transcriptional factors inducing epithelial-mesenchymal transition, such as Twist, Snail, and Akt, play important roles in cell migration and cancer metastasis. Moscatilin inhibited the mRNA and protein expression of Twist, but not that of Snail, and subsequently inhibited N-cadherin expression. However, these effects were reversed by constitutively expressing active myristoylated (myr)-Akt and Twist overexpression. Moscatilin also suppressed Akt phosphorylation. However, Akt overexpression reversed the inhibitory effects of moscatilin on phospho-Akt protein expression but not its effects on Twist. The moscatilin-mediated inhibition of cell migration was reversed by Akt and Twist overexpression, demonstrating that moscatilin blocked cell migration by inhibiting Akt and Twist. In an MDA-MB-231 metastatic animal model, moscatilin (100 mg/kg) significantly suppressed breast cancer metastasis to the lungs and reduced the number of metastatic lung nodules and lung weight without causing any toxicity. These results indicated that moscatilin inhibited MDA-MB-231 cell migration via Akt- and Twist-dependent pathways; this finding was consistent with moscatilin's antimetastatic activity in vivo. Therefore, moscatilin may be an effective compound for the prevention of human breast cancer metastasis.